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3 <!entity supported SYSTEM "supported.sgml">
4 <!entity newfeatures SYSTEM "newfeatures.sgml">
5 <!entity p-intro SYSTEM "privoxy.sgml">
6 <!entity seealso SYSTEM "seealso.sgml">
7 <!entity buildsource SYSTEM "buildsource.sgml">
8 <!entity contacting SYSTEM "contacting.sgml">
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10 <!entity copyright SYSTEM "copyright.sgml">
11 <!entity license SYSTEM "license.sgml">
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15 <!entity config SYSTEM "p-config.sgml">
16 <!entity changelog SYSTEM "changelog.sgml">
17 <!entity p-version "3.0.34">
18 <!entity p-status "stable">
19 <!entity % p-authors-formal "INCLUDE"> <!-- include additional text, etc -->
20 <!entity % p-not-stable "IGNORE">
21 <!entity % p-stable "INCLUDE">
22 <!entity % p-text "IGNORE"> <!-- define we are not a text only doc -->
23 <!entity % p-doc "INCLUDE"> <!-- and we are a formal doc -->
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25 <!entity % user-man "IGNORE">
26 <!entity % config-file "IGNORE">
27 <!entity % p-supp-userman "IGNORE"> <!-- Omit some from supported.sgml -->
28 <!entity my-copy "©"> <!-- kludge for docbook2man -->
29 <!entity % draft "IGNORE"> <!-- WIP stuff -->
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31 <!entity my-app "<application>Privoxy</application>">
34 File : doc/source/user-manual.sgml
38 Copyright (C) 2001-2023 Privoxy Developers https://www.privoxy.org/
41 ========================================================================
42 NOTE: Please read developer-manual/documentation.html before touching
43 anything in this, or other Privoxy documentation.
44 ========================================================================
51 <title>Privoxy &p-version; User Manual</title>
55 <!-- Completely the wrong markup, but very little is allowed -->
56 <!-- in this part of an article. FIXME -->
57 <link linkend="copyright">Copyright</link> &my-copy; 2001-2023 by
58 <ulink url="https://www.privoxy.org/">Privoxy Developers</ulink>
64 Note: the following should generate a separate page, and a live link to it,
65 all nicely done. But it doesn't for some mysterious reason. Please leave
66 commented unless it can be fixed proper. For the time being, the
67 copyright/license declarations will be in their own sgml.
80 This is here to keep vim syntax file from breaking :/
81 If I knew enough to fix it, I would.
82 PLEASE DO NOT REMOVE! HB: hal@foobox.net
88 The <citetitle>Privoxy User Manual</citetitle> gives users information on how to
89 install, configure and use <ulink
90 url="https://www.privoxy.org/">Privoxy</ulink>.
93 <!-- Include privoxy.sgml boilerplate: -->
95 <!-- end privoxy.sgml -->
98 You can find the latest version of the <citetitle>Privoxy User Manual</citetitle> at <ulink
99 url="https://www.privoxy.org/user-manual/">https://www.privoxy.org/user-manual/</ulink>.
100 Please see the <link linkend="contact">Contact section</link> on how to
101 contact the developers.
108 <!-- ~~~~~ New section ~~~~~ -->
109 <sect1 label="1" id="introduction"><title>Introduction</title>
111 This documentation is included with the current &p-status; version of
112 <application>Privoxy</application>, &p-version;<![%p-not-stable;[,
113 and is mostly complete at this point. The most up to date reference for the
114 time being is still the comments in the source files and in the individual
115 configuration files. Development of a new version is currently nearing
116 completion, and includes significant changes and enhancements over
120 <!-- include only in non-stable versions -->
123 Since this is a &p-status; version, not all new features are well tested. This
124 documentation may be slightly out of sync as a result (especially with
125 <ulink url="https://www.privoxy.org/gitweb/?p=privoxy.git;a=summary">git sources</ulink>).
126 And there <emphasis>may be</emphasis> bugs, though hopefully
131 <!-- ~~~~~ New section ~~~~~ -->
132 <sect2 id="features"><title>Features</title>
134 In addition to the core
135 features of ad blocking and
136 <ulink url="https://en.wikipedia.org/wiki/Browser_cookie">cookie</ulink> management,
137 <application>Privoxy</application> provides many supplemental
138 features<![%p-not-stable;[, some of them currently under development]]>,
139 that give the end-user more control, more privacy and more freedom:
141 <!-- Include newfeatures.sgml boilerplate here: -->
143 <!-- end boilerplate -->
148 <!-- ~ End section ~ -->
151 <!-- ~~~~~ New section ~~~~~ -->
152 <sect1 id="installation"><title>Installation</title>
155 <application>Privoxy</application> is available both in convenient pre-compiled
156 packages for a wide range of operating systems, and as raw source code.
157 For most users, we recommend using the packages, which can be downloaded from our
158 <ulink url="https://sourceforge.net/projects/ijbswa/">Privoxy Project
164 On some platforms, the installer may remove previously installed versions, if
165 found. (See below for your platform). In any case <emphasis>be sure to backup
166 your old configuration if it is valuable to you.</emphasis> See the <link
167 linkend="upgradersnote">note to upgraders</link> section below.
170 <!-- ~~~~~ New section ~~~~~ -->
171 <sect2 id="installation-packages"><title>Binary Packages</title>
173 How to install the binary packages depends on your operating system:
176 <!-- XXX: The installation sections should be sorted -->
178 <!-- ~~~~~ New section ~~~~~ -->
179 <sect3 id="installation-deb"><title>Debian and Ubuntu</title>
181 DEBs can be installed with <literal>apt-get install privoxy</literal>,
182 and will use <filename>/etc/privoxy</filename> for the location of
187 <!-- ~~~~~ New section ~~~~~ -->
188 <sect3 id="installation-pack-win"><title>Windows</title>
191 Just double-click the installer, which will guide you through
192 the installation process. You will find the configuration files
193 in the same directory as you installed <application>Privoxy</application> in.
196 Version 3.0.5 beta introduced full <application>Windows</application> service
197 functionality. On Windows only, the <application>Privoxy</application>
198 program has two new command line arguments to install and uninstall
199 <application>Privoxy</application> as a <emphasis>service</emphasis>.
203 <term>Arguments:</term>
206 <replaceable class="parameter">--install</replaceable>[:<replaceable class="parameter">service_name</replaceable>]
209 <replaceable class="parameter">--uninstall</replaceable>[:<replaceable class="parameter">service_name</replaceable>]
215 After invoking <application>Privoxy</application> with
216 <command>--install</command>, you will need to bring up the
217 <application>Windows</application> service console to assign the user you
218 want <application>Privoxy</application> to run under, and whether or not you
219 want it to run whenever the system starts. You can start the
220 <application>Windows</application> services console with the following
221 command: <command>services.msc</command>. If you do not take the manual step
222 of modifying <application>Privoxy's</application> service settings, it will
223 not start. Note too that you will need to give Privoxy a user account that
224 actually exists, or it will not be permitted to
225 write to its log and configuration files.
230 <!-- ~~~~~ New section ~~~~~ -->
231 <sect3 id="installation-mac"><title>Mac OS X</title>
233 Installation instructions for the OS X platform depend upon whether
234 you downloaded a ready-built installation package (.pkg or .mpkg) or have
235 downloaded the source code.
238 <sect3 renderas="sect4" id="OS-X-install-from-package">
239 <title>Installation from ready-built package</title>
241 The downloaded file will either be a .pkg (for OS X 10.5 upwards) or a bzipped
242 .mpkg file (for OS X 10.4). The former can be double-clicked as is and the
243 installation will start; double-clicking the latter will unzip the .mpkg file
244 which can then be double-clicked to commence the installation.
247 The privoxy service will automatically start after a successful installation
248 (and thereafter every time your computer starts up) however you will need to
249 configure your web browser(s) to use it. To do so, configure them to use a
250 proxy for HTTP and HTTPS at the address 127.0.0.1:8118.
253 To prevent the privoxy service from automatically starting when your computer
254 starts up, remove or rename the file <literal>/Library/LaunchDaemons/org.ijbswa.privoxy.plist</literal>
255 (on OS X 10.5 and higher) or the folder named
256 <literal>/Library/StartupItems/Privoxy</literal> (on OS X 10.4 'Tiger').
259 To manually start or stop the privoxy service, use the scripts startPrivoxy.sh
260 and stopPrivoxy.sh supplied in /Applications/Privoxy. They must be run from an
261 administrator account, using sudo.
264 To uninstall, run /Applications/Privoxy/uninstall.command as sudo from an
265 administrator account.
268 <sect3 renderas="sect4" id="OS-X-install-from-source">
269 <title>Installation from source</title>
271 To build and install the Privoxy source code on OS X you will need to obtain
272 the macsetup module from the Privoxy Sourceforge CVS repository (refer to
273 Sourceforge help for details of how to set up a CVS client to have read-only
274 access to the repository). This module contains scripts that leverage the usual
275 open-source tools (available as part of Apple's free of charge Xcode
276 distribution or via the usual open-source software package managers for OS X
277 (MacPorts, Homebrew, Fink etc.) to build and then install the privoxy binary
278 and associated files. The macsetup module's README file contains complete
279 instructions for its use.
282 The privoxy service will automatically start after a successful installation
283 (and thereafter every time your computer starts up) however you will need to
284 configure your web browser(s) to use it. To do so, configure them to use a
285 proxy for HTTP and HTTPS at the address 127.0.0.1:8118.
288 To prevent the privoxy service from automatically starting when your computer
289 starts up, remove or rename the file <literal>/Library/LaunchDaemons/org.ijbswa.privoxy.plist</literal>
290 (on OS X 10.5 and higher) or the folder named
291 <literal>/Library/StartupItems/Privoxy</literal> (on OS X 10.4 'Tiger').
294 To manually start or stop the privoxy service, use the Privoxy Utility
295 for Mac OS X (also part of the macsetup module). This application can start
296 and stop the privoxy service and display its log and configuration files.
299 To uninstall, run the macsetup module's uninstall.sh as sudo from an
300 administrator account.
304 <!-- ~~~~~ New section ~~~~~ -->
305 <sect3 id="installation-freebsd"><title>FreeBSD and ElectroBSD</title>
308 Privoxy is part of FreeBSD's Ports Collection, you can build and install
309 it with <literal>cd /usr/ports/www/privoxy; make install clean</literal>.
312 If your system is configured to install binary packages you can
313 try to install &my-app; with <literal>pkg install privoxy</literal>.
319 <!-- ~~~~~ New section ~~~~~ -->
320 <sect2 id="installation-source"><title>Building from Source</title>
323 The most convenient way to obtain the <application>Privoxy</application> source
324 code is to download the source tarball from our
325 <ulink url="https://sourceforge.net/projects/ijbswa/files/Sources/">
326 project download page</ulink>,
327 or you can get the up-to-the-minute, possibly unstable, development version from
328 <ulink url="https://www.privoxy.org/">https://www.privoxy.org/</ulink>.
331 <!-- include buildsource.sgml boilerplate: -->
333 <!-- end boilerplate -->
336 <sect3 id="WINBUILD-CYGWIN"><title>Windows</title>
338 <sect4 id="WINBUILD-SETUP"><title>Setup</title>
340 Install the Cygwin utilities needed to build <application>Privoxy</application>.
341 If you have a 64 bit CPU (which most people do by now), get the
342 Cygwin setup-x86_64.exe program <ulink url="https://cygwin.com/setup-x86_64.exe">here</ulink>
343 (the .sig file is <ulink url="https://cygwin.com/setup-x86_64.exe.sig">here</ulink>).
346 Run the setup program and from View / Category select:
358 mingw64-i686-gcc-core
363 libxslt: GNOME XSLT library (runtime)
379 If you haven't already downloaded the Privoxy source code, get it now:
384 git clone https://www.privoxy.org/git/privoxy.git
388 Get the source code (.zip or .tar.gz) for tidy from
389 <ulink url="https://github.com/htacg/tidy-html5/releases">
390 https://github.com/htacg/tidy-html5/releases</ulink>,
391 unzip into <root-dir> and build the software:
395 cd tidy-html5-x.y.z/build/cmake
396 cmake ../.. -DCMAKE_BUILD_TYPE=Release -DBUILD_SHARED_LIB:BOOL=OFF -DCMAKE_INSTALL_PREFIX=/usr/local
401 If you want to be able to make a Windows release package, get the NSIS .zip file from
402 <!-- FIXME: which version(s) are known to work? -->
403 <ulink url="https://sourceforge.net/projects/nsis/files/NSIS%203/">
404 https://sourceforge.net/projects/nsis/files/NSIS%203/</ulink>
405 and extract the NSIS directory to <literal>/<root-dir>/nsis/</literal>.
406 Then edit the <filename>windows/GNUmakefile</filename> to set the location
407 of the NSIS executable - eg:
411 MAKENSIS = /<root-dir>/nsis/makensis.exe
415 Get the latest 8.x PCRE code from
416 <ulink url="https://sourceforge.net/projects/pcre/files/pcre/">PCRE
417 https://sourceforge.net/projects/pcre/files/pcre/</ulink>
418 and build the static PCRE libraries with
421 export CFLAGS="-O2 -fstack-protector-strong -D_FORTIFY_SOURCE=2"
422 export LDFLAGS="-fstack-protector-strong"
423 export CPPFLAGS="-DPCRE_STATIC"
425 ./configure --host=i686-w64-mingw32 \
426 --prefix=/usr/local/i686-w64-mingw32 \
427 --enable-utf --enable-unicode-properties \
429 --enable-newline-is-anycrlf \
432 --disable-pcregrep-libbz2 \
433 --disable-pcregrep-libz \
434 --disable-pcretest-libreadline \
435 --disable-stack-for-recursion \
436 --enable-static --disable-shared \
443 If you want to be able to have Privoxy do TLS Inspection, get the latest
444 2.28.x MBED-TLS library source code from
445 <ulink url="https://github.com/Mbed-TLS/mbedtls/tags">
446 https://github.com/Mbed-TLS/mbedtls/tags</ulink>,
447 extract the tar file into <literal><root-dir></literal>
448 and build the static libraries with
450 export WINDOWS_BUILD=1
451 # build for a Windows platform
455 export CC=i686-w64-mingw32-gcc
456 export LD=i686-w64-mingw32-gcc
457 export CFLAGS="-O2 -fstack-protector-strong -D_FORTIFY_SOURCE=2"
458 export LDFLAGS="${LDFLAGS} -fstack-protector-strong"
461 # build the libraries
467 Get the brotli library from
468 <ulink url="https://github.com/google/brotli/releases">
469 https://github.com/google/brotli/releases</ulink>
470 and build the static libraries with
473 # to create the GNU autotools files
477 export CFLAGS="-O2 -fstack-protector-strong -D_FORTIFY_SOURCE=2"
478 export LDFLAGS="${LDFLAGS} -fstack-protector-strong"
480 ./configure --host=i686-w64-mingw32 \
481 --prefix=/usr/local/i686-w64-mingw32 \
485 --disable-silent-rules \
494 <sect4 id="WINBUILD-BUILD"><title>Build</title>
497 To build just the Privoxy executable and not the whole installation package, do:
500 cd <root-dir>/privoxy
501 ./windows/MYconfigure && make
505 Privoxy uses the <ulink url="https://en.wikipedia.org/wiki/GNU_build_system">GNU Autotools</ulink>
506 for building software, so the process is:
509 autoheader # creates config.h.in
510 autoconf # uses config.h.in to create the configure shell script
511 ./configure [options] # creates GNUmakefile
512 make [options] # builds the program
516 The usual <literal>configure</literal> options for building a native Windows application under cygwin are
519 <literallayout class="Monospaced">
520 --host=i686-w64-mingw32
523 --enable-static-linking
530 You can set the <literal>CFLAGS</literal> and <literal>LDFLAGS</literal> envars before
531 running <literal>configure</literal> to set compiler and linker flags. For example:
535 $ export CFLAGS="-O2" # set gcc optimization level
536 $ export LDFLAGS="-Wl,--nxcompat" # Enable DEP
537 $ ./configure --host=i686-w64-mingw32 --enable-mingw32 --enable-zlib \
538 > --enable-static-linking --disable-pthread
539 $ make # build Privoxy
543 See the <ulink url="../developer-manual/newrelease.html#NEWRELEASE-WINDOWS">Developer's Manual</ulink>
544 for building a Windows release package.
552 <!-- ~~~~~ New section ~~~~~ -->
553 <sect2 id="installation-keepupdated"><title>Keeping your Installation Up-to-Date</title>
556 If you wish to receive an email notification whenever we release updates of
557 <application>Privoxy</application> or the actions file, <ulink
558 url="https://lists.privoxy.org/mailman/listinfo/privoxy-announce">subscribe
559 to our announce mailing list</ulink>, privoxy-announce@lists.privoxy.org.
563 In order not to lose your personal changes and adjustments when updating
564 to the latest <literal>default.action</literal> file we <emphasis>strongly
565 recommend</emphasis> that you use <literal>user.action</literal> and
566 <literal>user.filter</literal> for your local
567 customizations of <application>Privoxy</application>. See the <link
568 linkend="actions-file">Chapter on actions files</link> for details.
576 <!-- ~ End section ~ -->
578 <!-- ~~~~~ New section ~~~~~ -->
579 <sect1 id="whatsnew">
580 <title>What's New in this Release</title>
584 <!-- ~~~~~ New section ~~~~~ -->
586 <sect2 id="upgradersnote">
587 <title>Note to Upgraders</title>
590 A quick list of things to be aware of before upgrading from earlier
591 versions of <application>Privoxy</application>:
598 The recommended way to upgrade &my-app; is to backup your old
599 configuration files, install the new ones, verify that &my-app;
600 is working correctly and finally merge back your changes using
601 <application>diff</application> and maybe <application>patch</application>.
604 There are a number of new features in each &my-app; release and
605 most of them have to be explicitly enabled in the configuration
606 files. Old configuration files obviously don't do that and due
607 to syntax changes using old configuration files with a new
608 &my-app; isn't always possible anyway.
613 Note that some installers remove earlier versions completely,
614 including configuration files, therefore you should really save
615 any important configuration files!
620 On the other hand, other installers don't overwrite existing configuration
621 files, thinking you will want to do that yourself.
626 In the default configuration only fatal errors are logged now.
627 You can change that in the <link linkend="DEBUG">debug section</link>
628 of the configuration file. You may also want to enable more verbose
629 logging until you verified that the new &my-app; version is working
636 Three other config file settings are now off by default:
637 <link linkend="enable-remote-toggle">enable-remote-toggle</link>,
638 <link linkend="enable-remote-http-toggle">enable-remote-http-toggle</link>,
639 and <link linkend="enable-edit-actions">enable-edit-actions</link>.
640 If you use or want these, you will need to explicitly enable them, and
641 be aware of the security issues involved.
648 What constitutes a <quote>default</quote> configuration has changed,
649 and you may want to review which actions are <quote>on</quote> by
650 default. This is primarily a matter of emphasis, but some features
651 you may have been used to, may now be <quote>off</quote> by default.
652 There are also a number of new actions and filters you may want to
653 consider, most of which are not fully incorporated into the default
654 settings as yet (see above).
661 The default actions setting is now <literal>Cautious</literal>. Previous
662 releases had a default setting of <literal>Medium</literal>. Experienced
663 users may want to adjust this, as it is fairly conservative by &my-app;
664 standards and past practices. See <ulink
665 url="http://config.privoxy.org/edit-actions-list?f=default">
666 http://config.privoxy.org/edit-actions-list?f=default</ulink>. New users
667 should try the default settings for a while before turning up the volume.
673 The default setting has filtering turned <emphasis>off</emphasis>, which
674 subsequently means that compression is <emphasis>on</emphasis>. Remember
675 that filtering does not work on compressed pages, so if you use, or want to
676 use, filtering, you will need to force compression off. Example:
679 { +<link linkend="filter">filter</link>{google} +<link linkend="prevent-compression">prevent-compression</link> }
683 Or if you use a number of filters, or filter many sites, you may just want
684 to turn off compression for all sites in
685 <filename>default.action</filename> (or
686 <filename>user.action</filename>).
693 Also, <link linkend="SESSION-COOKIES-ONLY">session-cookies-only</link> is
694 off by default now. If you've liked this feature in the past, you may want
695 to turn it back on in <filename>user.action</filename> now.
702 Some installers may not automatically start
703 <application>Privoxy</application> after installation.
713 <!-- ~~~~~ New section ~~~~~ -->
714 <sect1 id="quickstart"><title>Quickstart to Using Privoxy</title>
720 Install <application>Privoxy</application>. See the <link
721 linkend="installation">Installation Section</link> below for platform specific
728 Advanced users and those who want to offer <application>Privoxy</application>
729 service to more than just their local machine should check the <link
730 linkend="config">main config file</link>, especially the <link
731 linkend="access-control">security-relevant</link> options. These are
738 Start <application>Privoxy</application>, if the installation program has
739 not done this already (may vary according to platform). See the section
740 <link linkend="startup">Starting <application>Privoxy</application></link>.
746 Set your browser to use <application>Privoxy</application> as HTTP and
747 HTTPS (SSL) <ulink url="https://en.wikipedia.org/wiki/Proxy_server">proxy</ulink>
748 by setting the proxy configuration for address of
749 <literal>127.0.0.1</literal> and port <literal>8118</literal>.
750 <emphasis>DO NOT</emphasis> activate proxying for <literal>FTP</literal> or
751 any protocols besides HTTP and HTTPS (SSL) unless you intend to prevent your
752 browser from using these protocols.
758 Flush your browser's disk and memory caches, to remove any cached ad images.
759 If using <application>Privoxy</application> to manage
760 <ulink url="https://en.wikipedia.org/wiki/Browser_cookie">cookies</ulink>,
761 you should remove any currently stored cookies too.
767 A default installation should provide a reasonable starting point for
768 most. There will undoubtedly be occasions where you will want to adjust the
769 configuration, but that can be dealt with as the need arises. Little
770 to no initial configuration is required in most cases, you may want
772 <ulink url="config.html#ENABLE-EDIT-ACTIONS">web-based action editor</ulink> though.
773 Be sure to read the warnings first.
776 See the <link linkend="configuration">Configuration section</link> for more
777 configuration options, and how to customize your installation.
778 You might also want to look at the <link
779 linkend="quickstart-ad-blocking">next section</link> for a quick
780 introduction to how <application>Privoxy</application> blocks ads and
787 If you experience ads that slip through, innocent images that are
788 blocked, or otherwise feel the need to fine-tune
789 <application>Privoxy's</application> behavior, take a look at the <link
790 linkend="actions-file">actions files</link>. As a quick start, you might
791 find the <link linkend="act-examples">richly commented examples</link>
792 helpful. You can also view and edit the actions files through the <ulink
793 url="http://config.privoxy.org">web-based user interface</ulink>. The
794 Appendix <quote><link linkend="actionsanat">Troubleshooting: Anatomy of an
795 Action</link></quote> has hints on how to understand and debug actions that
796 <quote>misbehave</quote>.
802 Please see the section <link linkend="contact">Contacting the
803 Developers</link> on how to report bugs, problems with websites or to get
810 Now enjoy surfing with enhanced control, comfort and privacy!
817 <!-- ~~~~~ New section ~~~~~ -->
819 <sect2 id="quickstart-ad-blocking">
820 <title>Quickstart to Ad Blocking</title>
822 NOTE: This section is deliberately redundant for those that don't
823 want to read the whole thing (which is getting lengthy).
826 Ad blocking is but one of <application>Privoxy's</application>
827 array of features. Many of these features are for the technically minded advanced
828 user. But, ad and banner blocking is surely common ground for everybody.
831 This section will provide a quick summary of ad blocking so
832 you can get up to speed quickly without having to read the more extensive
833 information provided below, though this is highly recommended.
836 First a bit of a warning ... blocking ads is much like blocking SPAM: the
837 more aggressive you are about it, the more likely you are to block
838 things that were not intended. And the more likely that some things
839 may not work as intended. So there is a trade off here. If you want
840 extreme ad free browsing, be prepared to deal with more
841 <quote>problem</quote> sites, and to spend more time adjusting the
842 configuration to solve these unintended consequences. In short, there is
843 not an easy way to eliminate <emphasis>all</emphasis> ads. Either take
844 the easy way and settle for <emphasis>most</emphasis> ads blocked with the
845 default configuration, or jump in and tweak it for your personal surfing
846 habits and preferences.
849 Secondly, a brief explanation of <application>Privoxy's </application>
850 <quote>actions</quote>. <quote>Actions</quote> in this context, are
851 the directives we use to tell <application>Privoxy</application> to perform
852 some task relating to HTTP transactions (i.e. web browsing). We tell
853 <application>Privoxy</application> to take some <quote>action</quote>. Each
854 action has a unique name and function. While there are many potential
855 <application>actions</application> in <application>Privoxy's</application>
856 arsenal, only a few are used for ad blocking. <link
857 linkend="actions">Actions</link>, and <link linkend="actions-file">action
858 configuration files</link>, are explained in depth below.
861 Actions are specified in <application>Privoxy's</application> configuration,
862 followed by one or more URLs to which the action should apply. URLs
863 can actually be URL type <link linkend="af-patterns">patterns</link> that use
864 wildcards so they can apply potentially to a range of similar URLs. The
865 actions, together with the URL patterns are called a section.
868 When you connect to a website, the full URL will either match one or more
869 of the sections as defined in <application>Privoxy's</application> configuration,
870 or not. If so, then <application>Privoxy</application> will perform the
871 respective actions. If not, then nothing special happens. Furthermore, web
872 pages may contain embedded, secondary URLs that your web browser will
873 use to load additional components of the page, as it parses the
874 original page's HTML content. An ad image for instance, is just an URL
875 embedded in the page somewhere. The image itself may be on the same server,
876 or a server somewhere else on the Internet. Complex web pages will have many
877 such embedded URLs. &my-app; can deal with each URL individually, so, for
878 instance, the main page text is not touched, but images from such-and-such
883 The most important actions for basic ad blocking are: <literal><link
884 linkend="block">block</link></literal>, <literal><link
885 linkend="handle-as-image">handle-as-image</link></literal>,
887 linkend="handle-as-empty-document">handle-as-empty-document</link></literal>,and
888 <literal><link linkend="set-image-blocker">set-image-blocker</link></literal>:
895 <literal><link linkend="block">block</link></literal> - this is perhaps
896 the single most used action, and is particularly important for ad blocking.
897 This action stops any contact between your browser and any URL patterns
898 that match this action's configuration. It can be used for blocking ads,
899 but also anything that is determined to be unwanted. By itself, it simply
900 stops any communication with the remote server and sends
901 <application>Privoxy</application>'s own built-in BLOCKED page instead to
902 let you now what has happened (with some exceptions, see below).
908 <literal><link linkend="handle-as-image">handle-as-image</link></literal> -
909 tells <application>Privoxy</application> to treat this URL as an image.
910 <application>Privoxy</application>'s default configuration already does this
911 for all common image types (e.g. GIF), but there are many situations where this
912 is not so easy to determine. So we'll force it in these cases. This is particularly
913 important for ad blocking, since only if we know that it's an image of
914 some kind, can we replace it with an image of our choosing, instead of the
915 <application>Privoxy</application> BLOCKED page (which would only result in
916 a <quote>broken image</quote> icon). There are some limitations to this
917 though. For instance, you can't just brute-force an image substitution for
918 an entire HTML page in most situations.
924 <literal><link linkend="handle-as-empty-document">handle-as-empty-document</link></literal> -
925 sends an empty document instead of <application>Privoxy's</application>
926 normal BLOCKED HTML page. This is useful for file types that are neither
927 HTML nor images, such as blocking JavaScript files.
934 linkend="set-image-blocker">set-image-blocker</link></literal> - tells
935 <application>Privoxy</application> what to display in place of an ad image that
936 has hit a block rule. For this to come into play, the URL must match a
937 <literal><link linkend="block">block</link></literal> action somewhere in the
938 configuration, <emphasis>and</emphasis>, it must also match an
939 <literal><link linkend="handle-as-image">handle-as-image</link></literal> action.
942 The configuration options on what to display instead of the ad are:
946 <emphasis>pattern</emphasis> - a checkerboard pattern, so that an ad
947 replacement is obvious. This is the default.
952 <emphasis>blank</emphasis> - A very small empty GIF image is displayed.
953 This is the so-called <quote>invisible</quote> configuration option.
958 <emphasis>http://<URL></emphasis> - A redirect to any image anywhere
959 of the user's choosing (advanced usage).
967 Advanced users will eventually want to explore &my-app;
968 <literal><link linkend="filter">filters</link></literal> as well. Filters
969 are very different from <literal><link
970 linkend="block">blocks</link></literal>.
971 A <quote>block</quote> blocks a site, page, or unwanted contented. Filters
972 are a way of filtering or modifying what is actually on the page. An example
973 filter usage: a text replacement of <quote>no-no</quote> for
974 <quote>nasty-word</quote>. That is a very simple example. This process can be
975 used for ad blocking, but it is more in the realm of advanced usage and has
976 some pitfalls to be wary off.
980 The quickest way to adjust any of these settings is with your browser through
981 the special <application>Privoxy</application> editor at <ulink
982 url="http://config.privoxy.org/show-status">http://config.privoxy.org/show-status</ulink>
983 (shortcut: <ulink url="http://p.p/">http://p.p/show-status</ulink>). This
984 is an internal page, and does not require Internet access.
988 Note that as of <application>Privoxy</application> 3.0.7 beta the
989 action editor is disabled by default. Check the
990 <ulink url="config.html#ENABLE-EDIT-ACTIONS">enable-edit-actions
991 section in the configuration file</ulink> to learn why and in which
992 cases it's safe to enable again.
996 If you decided to enable the action editor, select the appropriate
997 <quote>actions</quote> file, and click
998 <quote><guibutton>Edit</guibutton></quote>. It is best to put personal or
999 local preferences in <filename>user.action</filename> since this is not
1000 meant to be overwritten during upgrades, and will over-ride the settings in
1001 other files. Here you can insert new <quote>actions</quote>, and URLs for ad
1002 blocking or other purposes, and make other adjustments to the configuration.
1003 <application>Privoxy</application> will detect these changes automatically.
1007 A quick and simple step by step example:
1014 Right click on the ad image to be blocked, then select
1015 <quote><guimenuitem>Copy Link Location</guimenuitem></quote> from the
1023 url="http://config.privoxy.org/show-status">http://config.privoxy.org/show-status</ulink>
1028 Find <filename>user.action</filename> in the top section, and click
1029 on <quote><guibutton>Edit</guibutton></quote>:
1032 <!-- image of editor and actions files selections -->
1033 <figure pgwide="0" float="0"><title>Actions Files in Use</title>
1036 <imagedata fileref="files-in-use.jpg" format="jpg">
1039 <phrase>[ Screenshot of Actions Files in Use ]</phrase>
1047 You should have a section with only
1048 <literal><link linkend="block">block</link></literal> listed under
1049 <quote>Actions:</quote>.
1050 If not, click a <quote><guibutton>Insert new section below</guibutton></quote>
1051 button, and in the new section that just appeared, click the
1052 <guibutton>Edit</guibutton> button right under the word <quote>Actions:</quote>.
1053 This will bring up a list of all actions. Find
1054 <literal><link linkend="block">block</link></literal> near the top, and click
1055 in the <quote>Enabled</quote> column, then <quote><guibutton>Submit</guibutton></quote>
1056 just below the list.
1061 Now, in the <literal><link linkend="block">block</link></literal> actions section,
1062 click the <quote><guibutton>Add</guibutton></quote> button, and paste the URL the
1063 browser got from <quote><guimenuitem>Copy Link Location</guimenuitem></quote>.
1064 Remove the <literal>http://</literal> at the beginning of the URL. Then, click
1065 <quote><guibutton>Submit</guibutton></quote> (or
1066 <quote><guibutton>OK</guibutton></quote> if in a pop-up window).
1071 Now go back to the original page, and press <keycap>SHIFT-Reload</keycap>
1072 (or flush all browser caches). The image should be gone now.
1079 This is a very crude and simple example. There might be good reasons to use a
1080 wildcard pattern match to include potentially similar images from the same
1081 site. For a more extensive explanation of <quote>patterns</quote>, and
1082 the entire actions concept, see <link linkend="actions-file">the Actions
1087 For advanced users who want to hand edit their config files, you might want
1088 to now go to the <link linkend="act-examples">Actions Files Tutorial</link>.
1089 The ideas explained therein also apply to the web-based editor.
1092 There are also various
1093 <link linkend="filter">filters</link> that can be used for ad blocking
1094 (filters are a special subset of actions). These
1095 fall into the <quote>advanced</quote> usage category, and are explained in
1096 depth in later sections.
1103 <!-- ~ End section ~ -->
1106 <!-- ~~~~~ New section ~~~~~ -->
1107 <sect1 id="startup">
1108 <title>Starting Privoxy</title>
1110 Before launching <application>Privoxy</application> for the first time, you
1111 will want to configure your browser(s) to use
1112 <application>Privoxy</application> as a HTTP and HTTPS (SSL)
1113 <ulink url="https://en.wikipedia.org/wiki/Proxy_server">proxy</ulink>. The default is
1114 127.0.0.1 (or localhost) for the proxy address, and port 8118 (earlier versions
1115 used port 8000). This is the one configuration step <emphasis>that must be done
1119 Please note that <application>Privoxy</application> can only proxy HTTP and
1120 HTTPS traffic. It will not work with FTP or other protocols.
1123 <!-- image of Mozilla Proxy configuration -->
1124 <figure pgwide="0" float="0"><title>Proxy Configuration Showing
1125 Mozilla Firefox HTTP and HTTPS (SSL) Settings</title>
1128 <imagedata fileref="proxy_setup.jpg" format="jpg">
1131 <phrase>[ Screenshot of Mozilla Firefox Proxy Configuration ]</phrase>
1138 With <application>Firefox</application>, this is typically set under:
1142 <guibutton>Edit</guibutton> -> <guibutton>Preferences</guibutton> -> <guibutton>Network Settings</guibutton> -> <guibutton>Settings</guibutton>
1146 Or optionally on some platforms:
1150 <guibutton>Edit</guibutton> -> <guibutton>Preferences</guibutton> -> <guibutton>General</guibutton> -> <guibutton>Connection Settings</guibutton> -> <guibutton>Manual Proxy Configuration</guibutton>
1155 With <application>Netscape</application> (and
1156 <application>Mozilla</application>), this can be set under:
1161 <!-- Mix ascii and gui art, something for everybody -->
1162 <!-- spacing on this is tricky -->
1163 <guibutton>Edit</guibutton> -> <guibutton>Preferences</guibutton> -> <guibutton>Advanced</guibutton> -> <guibutton>Proxies</guibutton> -> <guibutton>HTTP Proxy</guibutton>
1167 For <application>Internet Explorer v.5-7</application>:
1171 <guibutton>Tools</guibutton> -> <guibutton>Internet Options</guibutton> -> <guibutton>Connections</guibutton> -> <guibutton>LAN Settings</guibutton>
1175 Then, check <quote>Use Proxy</quote> and fill in the appropriate info
1176 (Address: 127.0.0.1, Port: 8118). Include HTTPS (SSL), if you want HTTPS
1177 proxy support too (sometimes labeled <quote>Secure</quote>). Make sure any
1178 checkboxes like <quote>Use the same proxy server for all protocols</quote> is
1179 <emphasis>UNCHECKED</emphasis>. You want only HTTP and HTTPS (SSL)!
1182 <!-- image of IE Proxy configuration -->
1183 <figure pgwide="0" float="0"><title>Proxy Configuration Showing
1184 Internet Explorer HTTP and HTTPS (Secure) Settings</title>
1187 <imagedata fileref="proxy2.jpg" format="jpg">
1190 <phrase>[ Screenshot of IE Proxy Configuration ]</phrase>
1197 After doing this, flush your browser's disk and memory caches to force a
1198 re-reading of all pages and to get rid of any ads that may be cached. Remove
1199 any <ulink url="https://en.wikipedia.org/wiki/Browser_cookie">cookies</ulink>,
1200 if you want <application>Privoxy</application> to manage that. You are now
1201 ready to start enjoying the benefits of using
1202 <application>Privoxy</application>!
1206 <application>Privoxy</application> itself is typically started by specifying the
1207 main configuration file to be used on the command line. If no configuration
1208 file is specified on the command line, <application>Privoxy</application>
1209 will look for a file named <filename>config</filename> in the current
1210 directory. Except on Win32 where it will try <filename>config.txt</filename>.
1213 <sect2 id="start-debian">
1214 <title>Debian</title>
1216 We use a script. Note that Debian typically starts &my-app; upon booting per
1217 default. It will use the file
1218 <filename>/etc/privoxy/config</filename> as its main configuration
1222 # /etc/init.d/privoxy start
1226 <sect2 id="start-freebsd">
1227 <title>FreeBSD and ElectroBSD</title>
1229 To start <application>Privoxy</application> upon booting, add
1230 "privoxy_enable='YES'" to <filename>/etc/rc.conf</filename>.
1231 <application>Privoxy</application> will use
1232 <filename>/usr/local/etc/privoxy/config</filename> as its main
1236 If you installed <application>Privoxy</application> into a jail, the
1237 paths above are relative to the jail root.
1240 To start <application>Privoxy</application> manually, run:
1243 # service privoxy onestart
1247 <sect2 id="start-windows">
1248 <title>Windows</title>
1250 Click on the &my-app; Icon to start <application>Privoxy</application>. If no configuration file is
1251 specified on the command line, <application>Privoxy</application> will look
1252 for a file named <filename>config.txt</filename>. Note that Windows will
1253 automatically start &my-app; when the system starts if you chose that option
1257 <application>Privoxy</application> can run with full Windows service functionality.
1258 On Windows only, the &my-app; program has two new command line arguments
1259 to install and uninstall &my-app; as a service. See the
1260 <link linkend="installation-pack-win">Windows Installation
1261 instructions</link> for details.
1265 <sect2 id="start-unices">
1266 <title>Generic instructions for Unix derivates (Solaris, NetBSD, HP-UX etc.)</title>
1268 Example Unix startup command:
1271 # /usr/sbin/privoxy --user privoxy /etc/privoxy/config
1274 Note that if you installed <application>Privoxy</application> through
1275 a package manager, the package will probably contain a platform-specific
1276 script or configuration file to start <application>Privoxy</application>
1281 <sect2 id="start-macosx">
1282 <title>Mac OS X</title>
1284 The privoxy service will automatically start after a successful installation
1285 (and thereafter every time your computer starts up) however you will need to
1286 configure your web browser(s) to use it. To do so, configure them to use a
1287 proxy for HTTP and HTTPS at the address 127.0.0.1:8118.
1290 To prevent the privoxy service from automatically starting when your computer
1291 starts up, remove or rename the file <literal>/Library/LaunchDaemons/org.ijbswa.privoxy.plist</literal>
1292 (on OS X 10.5 and higher) or the folder named
1293 <literal>/Library/StartupItems/Privoxy</literal> (on OS X 10.4 'Tiger').
1296 To manually start or stop the privoxy service, use the scripts startPrivoxy.sh
1297 and stopPrivoxy.sh supplied in /Applications/Privoxy. They must be run from an
1298 administrator account, using sudo.
1306 See the section <link linkend="cmdoptions">Command line options</link> for
1310 must find a better place for this paragraph
1313 The included default configuration files should give a reasonable starting
1314 point. Most of the per site configuration is done in the
1315 <ulink url="actions-file.html"><quote>actions</quote></ulink> files. These are
1316 where various cookie actions are defined, ad and banner blocking, and other
1317 aspects of <application>Privoxy</application> configuration. There are several
1318 such files included, with varying levels of aggressiveness.
1322 You will probably want to keep an eye out for sites for which you may prefer
1323 persistent cookies, and add these to your actions configuration as needed. By
1324 default, most of these will be accepted only during the current browser
1325 session (aka <quote>session cookies</quote>), unless you add them to the
1326 configuration. If you want the browser to handle this instead, you will need
1327 to edit <filename>user.action</filename> (or through the web based interface)
1328 and disable this feature. If you use more than one browser, it would make
1329 more sense to let <application>Privoxy</application> handle this. In which
1330 case, the browser(s) should be set to accept all cookies.
1334 Another feature where you will probably want to define exceptions for trusted
1335 sites is the popup-killing (through <ulink
1336 url="actions-file.html#FILTER-POPUPS"><quote>+filter{popups}</quote></ulink>),
1337 because your favorite shopping, banking, or leisure site may need
1338 popups (explained below).
1342 <application>Privoxy</application> does not support all of the optional HTTP/1.1
1343 features yet. In the unlikely event that you experience inexplicable problems
1344 with browsers that use HTTP/1.1 per default
1345 (like <application>Mozilla</application> or recent versions of I.E.), you might
1346 try to force HTTP/1.0 compatibility. For Mozilla, look under <literal>Edit ->
1347 Preferences -> Debug -> Networking</literal>.
1348 Alternatively, set the <quote>+downgrade-http-version</quote> config option in
1349 <filename>default.action</filename> which will downgrade your browser's HTTP
1350 requests from HTTP/1.1 to HTTP/1.0 before processing them.
1354 After running <application>Privoxy</application> for a while, you can
1355 start to fine tune the configuration to suit your personal, or site,
1356 preferences and requirements. There are many, many aspects that can
1357 be customized. <quote>Actions</quote>
1358 can be adjusted by pointing your browser to
1359 <ulink url="http://config.privoxy.org/">http://config.privoxy.org/</ulink>
1360 (shortcut: <ulink url="http://p.p/">http://p.p/</ulink>),
1361 and then follow the link to <quote>View & Change the Current Configuration</quote>.
1362 (This is an internal page and does not require Internet access.)
1366 In fact, various aspects of <application>Privoxy</application>
1367 configuration can be viewed from this page, including
1368 current configuration parameters, source code version numbers,
1369 the browser's request headers, and <quote>actions</quote> that apply
1370 to a given URL. In addition to the actions file
1371 editor mentioned above, <application>Privoxy</application> can also
1372 be turned <quote>on</quote> and <quote>off</quote> (toggled) from this page.
1376 If you encounter problems, try loading the page without
1377 <application>Privoxy</application>. If that helps, enter the URL where
1378 you have the problems into <ulink url="http://p.p/show-url-info">the browser
1379 based rule tracing utility</ulink>. See which rules apply and why, and
1380 then try turning them off for that site one after the other, until the problem
1381 is gone. When you have found the culprit, you might want to turn the rest on
1386 If the above paragraph sounds gibberish to you, you might want to <link
1387 linkend="actions-file">read more about the actions concept</link>
1388 or even dive deep into the <link linkend="actionsanat">Appendix
1393 If you can't get rid of the problem at all, think you've found a bug in
1394 Privoxy, want to propose a new feature or smarter rules, please see the
1395 section <link linkend="contact"><quote>Contacting the
1396 Developers</quote></link> below.
1401 <!-- ~~~~~ New section ~~~~~ -->
1402 <sect2 id="cmdoptions">
1403 <title>Command Line Options</title>
1405 <application>Privoxy</application> may be invoked with the following
1406 command-line options:
1413 <emphasis>--config-test</emphasis>
1416 Exit after loading the configuration files before binding to
1417 the listen address. The exit code signals whether or not the
1418 configuration files have been successfully loaded.
1421 If the exit code is 1, at least one of the configuration files
1422 is invalid, if it is 0, all the configuration files have been
1423 successfully loaded (but may still contain errors that can
1424 currently only be detected at run time).
1427 This option doesn't affect the log setting, combination with
1428 <emphasis>--no-daemon</emphasis> is recommended if a configured
1429 log file shouldn't be used.
1434 <emphasis>--version</emphasis>
1437 Print version info and exit. Unix only.
1442 <emphasis>--help</emphasis>
1445 Print short usage info and exit. Unix only.
1450 <emphasis>--no-daemon</emphasis>
1453 Don't become a daemon, i.e. don't fork and become process group
1454 leader, and don't detach from controlling tty. Unix only.
1459 <emphasis>--pidfile FILE</emphasis>
1462 On startup, write the process ID to <emphasis>FILE</emphasis>. Delete the
1463 <emphasis>FILE</emphasis> on exit. Failure to create or delete the
1464 <emphasis>FILE</emphasis> is non-fatal. If no <emphasis>FILE</emphasis>
1465 option is given, no PID file will be used. Unix only.
1470 <emphasis>--user USER[.GROUP]</emphasis>
1473 After (optionally) writing the PID file, assume the user ID of
1474 <emphasis>USER</emphasis>, and if included the GID of GROUP. Exit if the
1475 privileges are not sufficient to do so. Unix only.
1480 <emphasis>--chroot</emphasis>
1483 Before changing to the user ID given in the <emphasis>--user</emphasis> option,
1484 chroot to that user's home directory, i.e. make the kernel pretend to the &my-app;
1485 process that the directory tree starts there. If set up carefully, this can limit
1486 the impact of possible vulnerabilities in &my-app; to the files contained in that hierarchy.
1492 <emphasis>--pre-chroot-nslookup hostname</emphasis>
1495 Specifies a hostname (for example www.privoxy.org) to look up before doing a chroot.
1496 On some systems, initializing the resolver library involves reading config files from
1497 /etc and/or loading additional shared libraries from /lib.
1498 On these systems, doing a hostname lookup before the chroot reduces
1499 the number of files that must be copied into the chroot tree.
1502 For fastest startup speed, a good value is a hostname that is not in /etc/hosts but that
1503 your local name server (listed in /etc/resolv.conf) can resolve without recursion
1504 (that is, without having to ask any other name servers). The hostname need not exist,
1505 but if it doesn't, an error message (which can be ignored) will be output.
1511 <emphasis>configfile</emphasis>
1514 If no <emphasis>configfile</emphasis> is included on the command line,
1515 <application>Privoxy</application> will look for a file named
1516 <quote>config</quote> in the current directory (except on Win32
1517 where it will look for <quote>config.txt</quote> instead). Specify
1518 full path to avoid confusion. If no config file is found,
1519 <application>Privoxy</application> will fail to start.
1526 On <application>MS Windows</application> only there are two additional
1527 command-line options to allow <application>Privoxy</application> to install and
1528 run as a <emphasis>service</emphasis>. See the
1529 <link linkend="installation-pack-win">Window Installation section</link>
1537 <!-- ~ End section ~ -->
1540 <!-- ~~~~~ New section ~~~~~ -->
1541 <sect1 id="configuration"><title>Privoxy Configuration</title>
1543 All <application>Privoxy</application> configuration is stored
1544 in text files. These files can be edited with a text editor.
1545 Many important aspects of <application>Privoxy</application> can
1546 also be controlled easily with a web browser.
1550 <!-- ~~~~~ New section ~~~~~ -->
1552 <sect2 id="control-with-webbrowser">
1553 <title>Controlling Privoxy with Your Web Browser</title>
1555 <application>Privoxy</application>'s user interface can be reached through the special
1556 URL <ulink url="http://config.privoxy.org/">http://config.privoxy.org/</ulink>
1557 (shortcut: <ulink url="http://p.p/">http://p.p/</ulink>),
1558 which is a built-in page and works without Internet access.
1559 You will see the following section:
1562 <!-- Needs to be put in a table and colorized -->
1563 <screen><!-- want the background color that goes with screen -->
1565 <bridgehead renderas="sect2"> Privoxy Menu</bridgehead>
1568 ▪ <ulink url="http://config.privoxy.org/show-status">View & change the current configuration</ulink>
1571 ▪ <ulink url="http://config.privoxy.org/client-tags">View or toggle the tags that can be set based on the client's address</ulink>
1574 ▪ <ulink url="http://config.privoxy.org/show-request">View the request headers.</ulink>
1577 ▪ <ulink url="http://config.privoxy.org/show-url-info">Look up which actions apply to a URL and why</ulink>
1580 ▪ <ulink url="http://config.privoxy.org/toggle">Toggle Privoxy on or off</ulink>
1583 ▪ <ulink
1584 url="https://www.privoxy.org/&p-version;/user-manual/">Documentation</ulink>
1592 This should be self-explanatory. Note the first item leads to an editor for the
1593 <link linkend="actions-file">actions files</link>, which is where the ad, banner,
1594 cookie, and URL blocking magic is configured as well as other advanced features of
1595 <application>Privoxy</application>. This is an easy way to adjust various
1596 aspects of <application>Privoxy</application> configuration. The actions
1597 file, and other configuration files, are explained in detail below.
1601 <quote>Toggle Privoxy On or Off</quote> is handy for sites that might
1602 have problems with your current actions and filters. You can in fact use
1603 it as a test to see whether it is <application>Privoxy</application>
1604 causing the problem or not. <application>Privoxy</application> continues
1605 to run as a proxy in this case, but all manipulation is disabled, i.e.
1606 <application>Privoxy</application> acts like a normal forwarding proxy.
1610 Note that several of the features described above are disabled by default
1611 in <application>Privoxy</application> 3.0.7 beta and later.
1613 <ulink url="config.html">configuration file</ulink> to learn why
1614 and in which cases it's safe to enable them again.
1619 <!-- ~ End section ~ -->
1624 <!-- ~~~~~ New section ~~~~~ -->
1626 <sect2 id="confoverview">
1627 <title>Configuration Files Overview</title>
1629 For Unix, *BSD and GNU/Linux, all configuration files are located in
1630 <filename>/etc/privoxy/</filename> by default. For MS Windows
1631 these are all in the same directory as the
1632 <application>Privoxy</application> executable. <![%p-not-stable;[ The name
1633 and number of configuration files has changed from previous versions, and is
1634 subject to change as development progresses.]]>
1638 The installed defaults provide a reasonable starting point, though
1639 some settings may be aggressive by some standards. For the time being, the
1640 principle configuration files are:
1647 The <link linkend="config">main configuration file</link> is named <filename>config</filename>
1648 on GNU/Linux, Unix, BSD, and <filename>config.txt</filename>
1649 on Windows. This is a required file.
1655 <filename>match-all.action</filename> is used to define which <quote>actions</quote>
1656 relating to banner-blocking, images, pop-ups, content modification, cookie handling
1657 etc should be applied by default. It should be the first actions file loaded.
1660 <filename>default.action</filename> defines many exceptions (both positive and negative)
1661 from the default set of actions that's configured in <filename>match-all.action</filename>.
1662 It should be the second actions file loaded and shouldn't be edited by the user.
1665 Multiple actions files may be defined in <filename>config</filename>. These
1666 are processed in the order they are defined. Local customizations and locally
1667 preferred exceptions to the default policies as defined in
1668 <filename>match-all.action</filename> (which you will most probably want
1669 to define sooner or later) are best applied in <filename>user.action</filename>,
1670 where you can preserve them across upgrades. The file isn't installed by all
1671 installers, but you can easily create it yourself with a text editor.
1674 There is also a web based editor that can be accessed from
1676 url="http://config.privoxy.org/show-status">http://config.privoxy.org/show-status</ulink>
1678 url="http://p.p/show-status">http://p.p/show-status</ulink>) for the
1679 various actions files.
1685 <quote>Filter files</quote> (the <link linkend="filter-file">filter
1686 file</link>) can be used to re-write the raw page content, including
1687 viewable text as well as embedded HTML and JavaScript, and whatever else
1688 lurks on any given web page. The filtering jobs are only pre-defined here;
1689 whether to apply them or not is up to the actions files.
1690 <filename>default.filter</filename> includes various filters made
1691 available for use by the developers. Some are much more intrusive than
1692 others, and all should be used with caution. You may define additional
1693 filter files in <filename>config</filename> as you can with
1694 actions files. We suggest <filename>user.filter</filename> for any
1695 locally defined filters or customizations.
1702 The syntax of the configuration and filter files may change between different
1703 Privoxy versions, unfortunately some enhancements cost backwards compatibility.
1704 <!-- Add link to documentation-->
1708 All files use the <quote><literal>#</literal></quote> character to denote a
1709 comment (the rest of the line will be ignored) and understand line continuation
1710 through placing a backslash ("<literal>\</literal>") as the very last character
1711 in a line. If the <literal>#</literal> is preceded by a backslash, it looses
1712 its special function. Placing a <literal>#</literal> in front of an otherwise
1713 valid configuration line to prevent it from being interpreted is called "commenting
1714 out" that line. Blank lines are ignored.
1718 The actions files and filter files
1719 can use Perl style <link linkend="regex">regular expressions</link> for
1720 maximum flexibility.
1724 After making any changes, there is no need to restart
1725 <application>Privoxy</application> in order for the changes to take
1726 effect. <application>Privoxy</application> detects such changes
1727 automatically. Note, however, that it may take one or two additional
1728 requests for the change to take effect. When changing the listening address
1729 of <application>Privoxy</application>, these <quote>wake up</quote> requests
1730 must obviously be sent to the <emphasis>old</emphasis> listening address.
1735 While under development, the configuration content is subject to change.
1736 The below documentation may not be accurate by the time you read this.
1737 Also, what constitutes a <quote>default</quote> setting, may change, so
1738 please check all your configuration files on important issues.
1744 <!-- ~ End section ~ -->
1747 <!-- ~~~~~~~~ New section Header ~~~~~~~~~ -->
1749 <!-- **************************************************** -->
1750 <!-- Include config.sgml here -->
1751 <!-- This is where the entire config file is detailed. -->
1753 <!-- end include -->
1756 <!-- ~ End section ~ -->
1760 <!-- ~~~~~~~~ New section Header ~~~~~~~~~ -->
1762 <sect1 id="actions-file"><title>Actions Files</title>
1766 XXX: similar descriptions are in the Configuration Files sections.
1767 We should only describe them at one place.
1770 The actions files are used to define what <emphasis>actions</emphasis>
1771 <application>Privoxy</application> takes for which URLs, and thus determines
1772 how ad images, cookies and various other aspects of HTTP content and
1773 transactions are handled, and on which sites (or even parts thereof).
1774 There are a number of such actions, with a wide range of functionality.
1775 Each action does something a little different.
1776 These actions give us a veritable arsenal of tools with which to exert
1777 our control, preferences and independence. Actions can be combined so that
1778 their effects are aggregated when applied against a given set of URLs.
1782 are three action files included with <application>Privoxy</application> with
1788 <filename>match-all.action</filename> - is used to define which
1789 <quote>actions</quote> relating to banner-blocking, images, pop-ups,
1790 content modification, cookie handling etc should be applied by default.
1791 It should be the first actions file loaded
1796 <filename>default.action</filename> - defines many exceptions (both
1797 positive and negative) from the default set of actions that's configured
1798 in <filename>match-all.action</filename>. It is a set of rules that should
1799 work reasonably well as-is for most users. This file is only supposed to
1800 be edited by the developers. It should be the second actions file loaded.
1805 <filename>user.action</filename> - is intended to be for local site
1806 preferences and exceptions. As an example, if your ISP or your bank
1807 has specific requirements, and need special handling, this kind of
1808 thing should go here. This file will not be upgraded.
1813 <guibutton>Edit</guibutton> <guibutton>Set to Cautious</guibutton> <guibutton>Set to Medium</guibutton> <guibutton>Set to Advanced</guibutton>
1816 These have increasing levels of aggressiveness <emphasis>and have no
1817 influence on your browsing unless you select them explicitly in the
1818 editor</emphasis>. A default installation should be pre-set to
1819 <literal>Cautious</literal>. New users should try this for a while before
1820 adjusting the settings to more aggressive levels. The more aggressive
1821 the settings, then the more likelihood there is of problems such as sites
1822 not working as they should.
1825 The <guibutton>Edit</guibutton> button allows you to turn each
1826 action on/off individually for fine-tuning. The <guibutton>Cautious</guibutton>
1827 button changes the actions list to low/safe settings which will activate
1828 ad blocking and a minimal set of &my-app;'s features, and subsequently
1829 there will be less of a chance for accidental problems. The
1830 <guibutton>Medium</guibutton> button sets the list to a medium level of
1831 other features and a low level set of privacy features. The
1832 <guibutton>Advanced</guibutton> button sets the list to a high level of
1833 ad blocking and medium level of privacy. See the chart below. The latter
1834 three buttons over-ride any changes via with the
1835 <guibutton>Edit</guibutton> button. More fine-tuning can be done in the
1836 lower sections of this internal page.
1839 While the actions file editor allows to enable these settings in all
1840 actions files, they are only supposed to be enabled in the first one
1841 to make sure you don't unintentionally overrule earlier rules.
1844 The default profiles, and their associated actions, as pre-defined in
1845 <filename>default.action</filename> are:
1847 <table frame=all id="default-configurations"><title>Default Configurations</title>
1848 <tgroup cols=4 align=left colsep=1 rowsep=1>
1849 <colspec colname=c1>
1850 <colspec colname=c2>
1851 <colspec colname=c3>
1852 <colspec colname=c4>
1855 <entry>Feature</entry>
1856 <entry>Cautious</entry>
1857 <entry>Medium</entry>
1858 <entry>Advanced</entry>
1863 <!-- <entry>f1</entry> -->
1864 <!-- <entry>f2</entry> -->
1865 <!-- <entry>f3</entry> -->
1866 <!-- <entry>f4</entry> -->
1872 <entry>Ad-blocking Aggressiveness</entry>
1873 <entry>medium</entry>
1879 <entry>Ad-filtering by size</entry>
1886 <entry>Ad-filtering by link</entry>
1892 <entry>Pop-up killing</entry>
1893 <entry>blocks only</entry>
1894 <entry>blocks only</entry>
1895 <entry>blocks only</entry>
1899 <entry>Privacy Features</entry>
1901 <entry>medium</entry>
1902 <entry>medium/high</entry>
1906 <entry>Cookie handling</entry>
1908 <entry>session-only</entry>
1913 <entry>Referer forging</entry>
1920 <entry>GIF de-animation</entry>
1927 <entry>Fast redirects</entry>
1934 <entry>HTML taming</entry>
1941 <entry>JavaScript taming</entry>
1948 <entry>Web-bug killing</entry>
1955 <entry>Image tag reordering</entry>
1969 The list of actions files to be used are defined in the main configuration
1970 file, and are processed in the order they are defined (e.g.
1971 <filename>default.action</filename> is typically processed before
1972 <filename>user.action</filename>). The content of these can all be viewed and
1974 url="http://config.privoxy.org/show-status">http://config.privoxy.org/show-status</ulink>.
1975 The over-riding principle when applying actions, is that the last action that
1976 matches a given URL wins. The broadest, most general rules go first
1977 (defined in <filename>default.action</filename>),
1978 followed by any exceptions (typically also in
1979 <filename>default.action</filename>), which are then followed lastly by any
1980 local preferences (typically in <emphasis>user</emphasis><filename>.action</filename>).
1981 Generally, <filename>user.action</filename> has the last word.
1985 An actions file typically has multiple sections. If you want to use
1986 <quote>aliases</quote> in an actions file, you have to place the (optional)
1987 <link linkend="aliases">alias section</link> at the top of that file.
1988 Then comes the default set of rules which will apply universally to all
1989 sites and pages (be <emphasis>very careful</emphasis> with using such a
1990 universal set in <filename>user.action</filename> or any other actions file after
1991 <filename>default.action</filename>, because it will override the result
1992 from consulting any previous file). And then below that,
1993 exceptions to the defined universal policies. You can regard
1994 <filename>user.action</filename> as an appendix to <filename>default.action</filename>,
1995 with the advantage that it is a separate file, which makes preserving your
1996 personal settings across <application>Privoxy</application> upgrades easier.
2000 Actions can be used to block anything you want, including ads, banners, or
2001 just some obnoxious URL whose content you would rather not see. Cookies can be accepted
2002 or rejected, or accepted only during the current browser session (i.e. not
2003 written to disk), content can be modified, some JavaScripts tamed, user-tracking
2004 fooled, and much more. See below for a <link linkend="actions">complete list
2008 <!-- ~~~~~ New section ~~~~~ -->
2009 <sect2 id="right-mix">
2010 <title>Finding the Right Mix</title>
2012 Note that some <link linkend="actions">actions</link>, like cookie suppression
2013 or script disabling, may render some sites unusable that rely on these
2014 techniques to work properly. Finding the right mix of actions is not always easy and
2015 certainly a matter of personal taste. And, things can always change, requiring
2016 refinements in the configuration. In general, it can be said that the more
2017 <quote>aggressive</quote> your default settings (in the top section of the
2018 actions file) are, the more exceptions for <quote>trusted</quote> sites you
2019 will have to make later. If, for example, you want to crunch all cookies per
2020 default, you'll have to make exceptions from that rule for sites that you
2021 regularly use and that require cookies for actually useful purposes, like maybe
2022 your bank, favorite shop, or newspaper.
2026 We have tried to provide you with reasonable rules to start from in the
2027 distribution actions files. But there is no general rule of thumb on these
2028 things. There just are too many variables, and sites are constantly changing.
2029 Sooner or later you will want to change the rules (and read this chapter again :).
2033 <!-- ~~~~~ New section ~~~~~ -->
2034 <sect2 id="how-to-edit">
2035 <title>How to Edit</title>
2037 The easiest way to edit the actions files is with a browser by
2038 using our browser-based editor, which can be reached from <ulink
2039 url="http://config.privoxy.org/show-status">http://config.privoxy.org/show-status</ulink>.
2040 Note: the config file option <link
2041 linkend="enable-edit-actions">enable-edit-actions</link> must be enabled for
2042 this to work. The editor allows both fine-grained control over every single
2043 feature on a per-URL basis, and easy choosing from wholesale sets of defaults
2044 like <quote>Cautious</quote>, <quote>Medium</quote> or
2045 <quote>Advanced</quote>. Warning: the <quote>Advanced</quote> setting is more
2046 aggressive, and will be more likely to cause problems for some sites.
2047 Experienced users only!
2051 If you prefer plain text editing to GUIs, you can of course also directly edit the
2052 the actions files with your favorite text editor. Look at
2053 <filename>default.action</filename> which is richly commented with many
2059 <sect2 id="actions-apply">
2060 <title>How Actions are Applied to Requests</title>
2062 Actions files are divided into sections. There are special sections,
2063 like the <quote><link linkend="aliases">alias</link></quote> sections which will
2064 be discussed later. For now let's concentrate on regular sections: They have a
2065 heading line (often split up to multiple lines for readability) which consist
2066 of a list of actions, separated by whitespace and enclosed in curly braces.
2067 Below that, there is a list of URL and tag patterns, each on a separate line.
2071 To determine which actions apply to a request, the URL of the request is
2072 compared to all URL patterns in each <quote>action file</quote>.
2073 Every time it matches, the list of applicable actions for the request is
2074 incrementally updated, using the heading of the section in which the
2075 pattern is located. The same is done again for tags and tag patterns later on.
2079 If multiple applying sections set the same action differently,
2080 the last match wins. If not, the effects are aggregated.
2081 E.g. a URL might match a regular section with a heading line of <literal>{
2082 +<link linkend="handle-as-image">handle-as-image</link> }</literal>,
2083 then later another one with just <literal>{
2084 +<link linkend="block">block</link> }</literal>, resulting
2085 in <emphasis>both</emphasis> actions to apply. And there may well be
2086 cases where you will want to combine actions together. Such a section then
2091 { +<literal>handle-as-image</literal> +<literal>block{Banner ads.}</literal> }
2092 # Block these as if they were images. Send no block page.
2094 media.example.com/.*banners
2095 .example.com/images/ads/
2099 You can trace this process for URL patterns and any given URL by visiting <ulink
2100 url="http://config.privoxy.org/show-url-info">http://config.privoxy.org/show-url-info</ulink>.
2104 Examples and more detail on this is provided in the Appendix, <link linkend="ACTIONSANAT">
2105 Troubleshooting: Anatomy of an Action</link> section.
2109 <!-- ~~~~~ New section ~~~~~ -->
2110 <sect2 id="af-patterns">
2111 <title>Patterns</title>
2113 As mentioned, <application>Privoxy</application> uses <quote>patterns</quote>
2114 to determine what <emphasis>actions</emphasis> might apply to which sites and
2115 pages your browser attempts to access. These <quote>patterns</quote> use wild
2116 card type <emphasis>pattern</emphasis> matching to achieve a high degree of
2117 flexibility. This allows one expression to be expanded and potentially match
2118 against many similar patterns.
2122 Generally, an URL pattern has the form
2123 <literal><host><port>/<path></literal>, where the
2124 <literal><host></literal>, the <literal><port></literal>
2125 and the <literal><path></literal> are optional. (This is why the special
2126 <literal>/</literal> pattern matches all URLs). Note that the protocol
2127 portion of the URL pattern (e.g. <literal>http://</literal>) should
2128 <emphasis>not</emphasis> be included in the pattern. This is assumed already!
2131 The pattern matching syntax is different for the host and path parts of
2132 the URL. The host part uses a simple globbing type matching technique,
2133 while the path part uses more flexible
2134 <ulink url="https://en.wikipedia.org/wiki/Regular_expressions"><quote>Regular
2135 Expressions</quote></ulink> (POSIX 1003.2).
2138 The port part of a pattern is a decimal port number preceded by a colon
2139 (<literal>:</literal>). If the host part contains a numerical IPv6 address,
2140 it has to be put into angle brackets
2141 (<literal><</literal>, <literal>></literal>).
2146 <term><literal>www.example.com/</literal></term>
2149 is a host-only pattern and will match any request to <literal>www.example.com</literal>,
2150 regardless of which document on that server is requested. So ALL pages in
2151 this domain would be covered by the scope of this action. Note that a
2152 simple <literal>example.com</literal> is different and would NOT match.
2157 <term><literal>www.example.com</literal></term>
2160 means exactly the same. For host-only patterns, the trailing <literal>/</literal> may
2166 <term><literal>www.example.com/index.html</literal></term>
2169 matches all the documents on <literal>www.example.com</literal>
2170 whose name starts with <literal>/index.html</literal>.
2175 <term><literal>www.example.com/index.html$</literal></term>
2178 matches only the single document <literal>/index.html</literal>
2179 on <literal>www.example.com</literal>.
2184 <term><literal>/index.html$</literal></term>
2187 matches the document <literal>/index.html</literal>, regardless of the domain,
2188 i.e. on <emphasis>any</emphasis> web server anywhere.
2193 <term><literal>/</literal></term>
2196 Matches any URL because there's no requirement for either the
2197 domain or the path to match anything.
2202 <term><literal>:8000/</literal></term>
2205 Matches any URL pointing to TCP port 8000.
2210 <term><literal>10.0.0.1/</literal></term>
2213 Matches any URL with the host address <literal>10.0.0.1</literal>.
2214 (Note that the real URL uses plain brackets, not angle brackets.)
2219 <term><literal><2001:db8::1>/</literal></term>
2222 Matches any URL with the host address <literal>2001:db8::1</literal>.
2223 (Note that the real URL uses plain brackets, not angle brackets.)
2228 <term><literal>index.html</literal></term>
2231 matches nothing, since it would be interpreted as a domain name and
2232 there is no top-level domain called <literal>.html</literal>. So its
2240 <!-- ~~~~~ New section ~~~~~ -->
2241 <sect3 id="host-pattern"><title>The Host Pattern</title>
2244 The matching of the host part offers some flexible options: if the
2245 host pattern starts or ends with a dot, it becomes unanchored at that end.
2246 The host pattern is often referred to as domain pattern as it is usually
2247 used to match domain names and not IP addresses.
2253 <term><literal>.example.com</literal></term>
2256 matches any domain with first-level domain <literal>com</literal>
2257 and second-level domain <literal>example</literal>.
2258 For example <literal>www.example.com</literal>,
2259 <literal>example.com</literal> and <literal>foo.bar.baz.example.com</literal>.
2260 Note that it wouldn't match if the second-level domain was <literal>another-example</literal>.
2265 <term><literal>www.</literal></term>
2268 matches any domain that <emphasis>STARTS</emphasis> with
2269 <literal>www.</literal> (It also matches the domain
2270 <literal>www</literal> but most of the time that doesn't matter.)
2275 <term><literal>.example.</literal></term>
2278 matches any domain that <emphasis>CONTAINS</emphasis> <literal>.example.</literal>.
2279 And, by the way, also included would be any files or documents that exist
2280 within that domain since no path limitations are specified. (Correctly
2281 speaking: It matches any FQDN that contains <literal>example</literal> as
2282 a domain.) This might be <literal>www.example.com</literal>,
2283 <literal>news.example.de</literal>, or
2284 <literal>www.example.net/cgi/testing.pl</literal> for instance. All these
2292 Additionally, there are wild-cards that you can use in the domain names
2293 themselves. These work similarly to shell globbing type wild-cards:
2294 <quote>*</quote> represents zero or more arbitrary characters (this is
2296 <ulink url="https://en.wikipedia.org/wiki/Regular_expressions"><quote>Regular
2297 Expression</quote></ulink> based syntax of <quote>.*</quote>),
2298 <quote>?</quote> represents any single character (this is equivalent to the
2299 regular expression syntax of a simple <quote>.</quote>), and you can define
2300 <quote>character classes</quote> in square brackets which is similar to
2301 the same regular expression technique. All of this can be freely mixed:
2306 <term><literal>ad*.example.com</literal></term>
2309 matches <quote>adserver.example.com</quote>,
2310 <quote>ads.example.com</quote>, etc but not <quote>sfads.example.com</quote>
2315 <term><literal>*ad*.example.com</literal></term>
2318 matches all of the above, and then some.
2323 <term><literal>.?pix.com</literal></term>
2326 matches <literal>www.ipix.com</literal>,
2327 <literal>pictures.epix.com</literal>, <literal>a.b.c.d.e.upix.com</literal> etc.
2332 <term><literal>www[1-9a-ez].example.c*</literal></term>
2335 matches <literal>www1.example.com</literal>,
2336 <literal>www4.example.cc</literal>, <literal>wwwd.example.cy</literal>,
2337 <literal>wwwz.example.com</literal> etc., but <emphasis>not</emphasis>
2338 <literal>wwww.example.com</literal>.
2345 While flexible, this is not the sophistication of full regular expression based syntax.
2349 When compiled with FEATURE_PCRE_HOST_PATTERNS patterns can be prefixed with
2350 <quote>PCRE-HOST-PATTERN:</quote> in which case full regular expression
2351 (PCRE) can be used for the host pattern as well.
2356 <!-- ~ End section ~ -->
2359 <!-- ~~~~~ New section ~~~~~ -->
2360 <sect3 id="path-pattern"><title>The Path Pattern</title>
2363 <application>Privoxy</application> uses <quote>modern</quote> POSIX 1003.2
2364 <ulink url="https://en.wikipedia.org/wiki/Regular_expressions"><quote>Regular
2365 Expressions</quote></ulink> for matching the path portion (after the slash),
2366 and is thus more flexible.
2370 There is an <link linkend="regex">Appendix</link> with a brief quick-start into regular
2371 expressions, you also might want to have a look at your operating system's documentation
2372 on regular expressions (try <literal>man re_format</literal>).
2376 Note that the path pattern is automatically left-anchored at the <quote>/</quote>,
2377 i.e. it matches as if it would start with a <quote>^</quote> (regular expression speak
2378 for the beginning of a line).
2382 Please also note that matching in the path is <emphasis>CASE INSENSITIVE</emphasis>
2383 by default, but you can switch to case sensitive at any point in the pattern by using the
2384 <quote>(?-i)</quote> switch: <literal>www.example.com/(?-i)PaTtErN.*</literal> will match
2385 only documents whose path starts with <literal>PaTtErN</literal> in
2386 <emphasis>exactly</emphasis> this capitalization.
2391 <term><literal>.example.com/.*</literal></term>
2394 Is equivalent to just <quote>.example.com</quote>, since any documents
2395 within that domain are matched with or without the <quote>.*</quote>
2396 regular expression. This is redundant
2401 <term><literal>.example.com/.*/index.html$</literal></term>
2404 Will match any page in the domain of <quote>example.com</quote> that is
2405 named <quote>index.html</quote>, and that is part of some path. For
2406 example, it matches <quote>www.example.com/testing/index.html</quote> but
2407 NOT <quote>www.example.com/index.html</quote> because the regular
2408 expression called for at least two <quote>/'s</quote>, thus the path
2409 requirement. It also would match
2410 <quote>www.example.com/testing/index_html</quote>, because of the
2411 special meta-character <quote>.</quote>.
2416 <term><literal>.example.com/(.*/)?index\.html$</literal></term>
2419 This regular expression is conditional so it will match any page
2420 named <quote>index.html</quote> regardless of path which in this case can
2421 have one or more <quote>/'s</quote>. And this one must contain exactly
2422 <quote>.html</quote> (and end with that!).
2427 <term><literal>.example.com/(.*/)(ads|banners?|junk)</literal></term>
2430 This regular expression will match any path of <quote>example.com</quote>
2431 that contains any of the words <quote>ads</quote>, <quote>banner</quote>,
2432 <quote>banners</quote> (because of the <quote>?</quote>) or <quote>junk</quote>.
2433 The path does not have to end in these words, just contain them.
2434 The path has to contain at least two slashes (including the one at the beginning).
2439 <term><literal>.example.com/(.*/)(ads|banners?|junk)/.*\.(jpe?g|gif|png)$</literal></term>
2442 This is very much the same as above, except now it must end in either
2443 <quote>.jpg</quote>, <quote>.jpeg</quote>, <quote>.gif</quote> or <quote>.png</quote>. So this
2444 one is limited to common image formats.
2451 There are many, many good examples to be found in <filename>default.action</filename>,
2452 and more tutorials below in <link linkend="regex">Appendix on regular expressions</link>.
2457 <!-- ~ End section ~ -->
2460 <!-- ~~~~~ New section ~~~~~ -->
2461 <sect3 id="tag-pattern"><title>The Request Tag Pattern</title>
2464 Request tag patterns are used to change the applying actions based on the
2465 request's tags. Tags can be created based on HTTP headers with either
2466 the <link linkend="CLIENT-HEADER-TAGGER">client-header-tagger</link>
2467 or the <link linkend="SERVER-HEADER-TAGGER">server-header-tagger</link> action.
2471 Request tag patterns have to start with <quote>TAG:</quote>, so &my-app;
2472 can tell them apart from other patterns. Everything after the colon
2473 including white space, is interpreted as a regular expression with
2474 path pattern syntax, except that tag patterns aren't left-anchored
2475 automatically (&my-app; doesn't silently add a <quote>^</quote>,
2476 you have to do it yourself if you need it).
2480 To match all requests that are tagged with <quote>foo</quote>
2481 your pattern line should be <quote>TAG:^foo$</quote>,
2482 <quote>TAG:foo</quote> would work as well, but it would also
2483 match requests whose tags contain <quote>foo</quote> somewhere.
2484 <quote>TAG: foo</quote> wouldn't work as it requires white space.
2488 Sections can contain URL and request tag patterns at the same time,
2489 but request tag patterns are checked after the URL patterns and thus
2490 always overrule them, even if they are located before the URL patterns.
2494 Once a new request tag is added, Privoxy checks right away if it's matched by one
2495 of the request tag patterns and updates the action settings accordingly. As a result
2496 request tags can be used to activate other tagger actions, as long as these other
2497 taggers look for headers that haven't already be parsed.
2501 For example you could tag client requests which use the
2502 <literal>POST</literal> method,
2503 then use this tag to activate another tagger that adds a tag if cookies
2504 are sent, and then use a block action based on the cookie tag. This allows
2505 the outcome of one action, to be input into a subsequent action. However if
2506 you'd reverse the position of the described taggers, and activated the
2507 method tagger based on the cookie tagger, no method tags would be created.
2508 The method tagger would look for the request line, but at the time
2509 the cookie tag is created, the request line has already been parsed.
2513 While this is a limitation you should be aware of, this kind of
2514 indirection is seldom needed anyway and even the example doesn't
2515 make too much sense.
2520 <!-- ~~~~~ New section ~~~~~ -->
2521 <sect3 id="negative-tag-patterns"><title>The Negative Request Tag Patterns</title>
2524 To match requests that do not have a certain request tag, specify a negative tag pattern
2525 by prefixing the tag pattern line with either <quote>NO-REQUEST-TAG:</quote>
2526 or <quote>NO-RESPONSE-TAG:</quote> instead of <quote>TAG:</quote>.
2530 Negative request tag patterns created with <quote>NO-REQUEST-TAG:</quote> are checked
2531 after all client headers are scanned, the ones created with <quote>NO-RESPONSE-TAG:</quote>
2532 are checked after all server headers are scanned. In both cases all the created
2533 tags are considered.
2537 <!-- ~~~~~ New section ~~~~~ -->
2538 <sect3 id="client-tag-pattern"><title>The Client Tag Pattern</title>
2540 <!-- XXX: This section contains duplicates content from the
2541 client-specific-tag documentation. -->
2544 Client tag patterns are not set based on HTTP headers but based on
2545 the client's IP address. Users can enable them themselves, but the
2546 Privoxy admin controls which tags are available and what their effect
2551 After a client-specific tag has been defined with the
2552 <link linkend="client-specific-tag">client-specific-tag</link>,
2553 directive, action sections can be activated based on the tag by using a
2554 CLIENT-TAG pattern. The CLIENT-TAG pattern is evaluated at the same priority
2555 as URL patterns, as a result the last matching pattern wins. Tags that
2556 are created based on client or server headers are evaluated later on
2557 and can overrule CLIENT-TAG and URL patterns!
2560 The tag is set for all requests that come from clients that requested
2561 it to be set. Note that "clients" are differentiated by IP address,
2562 if the IP address changes the tag has to be requested again.
2565 Clients can request tags to be set by using the CGI interface <ulink
2566 url="http://config.privoxy.org/client-tags">http://config.privoxy.org/client-tags</ulink>.
2574 # If the admin defined the client-specific-tag circumvent-blocks,
2575 # and the request comes from a client that previously requested
2576 # the tag to be set, overrule all previous +block actions that
2577 # are enabled based on URL to CLIENT-TAG patterns.
2579 CLIENT-TAG:^circumvent-blocks$
2581 # This section is not overruled because it's located after
2583 {+block{Nobody is supposed to request this.}}
2584 example.org/blocked-example-page</screen>
2590 <!-- ~ End section ~ -->
2593 <!-- ~~~~~ New section ~~~~~ -->
2595 <sect2 id="actions">
2596 <title>Actions</title>
2598 All actions are disabled by default, until they are explicitly enabled
2599 somewhere in an actions file. Actions are turned on if preceded with a
2600 <quote>+</quote>, and turned off if preceded with a <quote>-</quote>. So a
2601 <literal>+action</literal> means <quote>do that action</quote>, e.g.
2602 <literal>+block</literal> means <quote>please block URLs that match the
2603 following patterns</quote>, and <literal>-block</literal> means <quote>don't
2604 block URLs that match the following patterns, even if <literal>+block</literal>
2605 previously applied.</quote>
2609 Again, actions are invoked by placing them on a line, enclosed in curly braces and
2610 separated by whitespace, like in
2611 <literal>{+some-action -some-other-action{some-parameter}}</literal>,
2612 followed by a list of URL patterns, one per line, to which they apply.
2613 Together, the actions line and the following pattern lines make up a section
2614 of the actions file.
2618 Actions fall into three categories:
2624 Boolean, i.e the action can only be <quote>enabled</quote> or
2625 <quote>disabled</quote>. Syntax:
2628 +<replaceable class="function">name</replaceable> # enable action <replaceable class="parameter">name</replaceable>
2629 -<replaceable class="function">name</replaceable> # disable action <replaceable class="parameter">name</replaceable>
2632 Example: <literal>+handle-as-image</literal>
2639 Parameterized, where some value is required in order to enable this type of action.
2643 +<replaceable class="function">name</replaceable>{<replaceable class="parameter">param</replaceable>} # enable action and set parameter to <replaceable class="parameter">param</replaceable>,
2644 # overwriting parameter from previous match if necessary
2645 -<replaceable class="function">name</replaceable> # disable action. The parameter can be omitted
2648 Note that if the URL matches multiple positive forms of a parameterized action,
2649 the last match wins, i.e. the params from earlier matches are simply ignored.
2652 Example: <literal>+hide-user-agent{Mozilla/5.0 (X11; U; FreeBSD i386; en-US; rv:1.8.1.4) Gecko/20070602 Firefox/2.0.0.4}</literal>
2658 Multi-value. These look exactly like parameterized actions,
2659 but they behave differently: If the action applies multiple times to the
2660 same URL, but with different parameters, <emphasis>all</emphasis> the parameters
2661 from <emphasis>all</emphasis> matches are remembered. This is used for actions
2662 that can be executed for the same request repeatedly, like adding multiple
2663 headers, or filtering through multiple filters. Syntax:
2666 +<replaceable class="function">name</replaceable>{<replaceable class="parameter">param</replaceable>} # enable action and add <replaceable class="parameter">param</replaceable> to the list of parameters
2667 -<replaceable class="function">name</replaceable>{<replaceable class="parameter">param</replaceable>} # remove the parameter <replaceable class="parameter">param</replaceable> from the list of parameters
2668 # If it was the last one left, disable the action.
2669 <replaceable class="parameter">-name</replaceable> # disable this action completely and remove all parameters from the list
2672 Examples: <literal>+add-header{X-Fun-Header: Some text}</literal> and
2673 <literal>+filter{html-annoyances}</literal>
2680 If nothing is specified in any actions file, no <quote>actions</quote> are
2681 taken. So in this case <application>Privoxy</application> would just be a
2682 normal, non-blocking, non-filtering proxy. You must specifically enable the
2683 privacy and blocking features you need (although the provided default actions
2684 files will give a good starting point).
2688 Later defined action sections always over-ride earlier ones of the same type.
2689 So exceptions to any rules you make, should come in the latter part of the file (or
2690 in a file that is processed later when using multiple actions files such
2691 as <filename>user.action</filename>). For multi-valued actions, the actions
2692 are applied in the order they are specified. Actions files are processed in
2693 the order they are defined in <filename>config</filename> (the default
2694 installation has three actions files). It also quite possible for any given
2695 URL to match more than one <quote>pattern</quote> (because of wildcards and
2696 regular expressions), and thus to trigger more than one set of actions! Last
2700 <!-- start actions listing -->
2702 The list of valid <application>Privoxy</application> actions are:
2706 <!-- ********************************************************** -->
2707 <!-- Please note the below defined actions use id's that are -->
2708 <!-- probably linked from other places, so please don't change. -->
2710 <!-- ********************************************************** -->
2713 <!-- ~~~~~ New section ~~~~~ -->
2715 <sect3 renderas="sect4" id="add-header">
2716 <title>add-header</title>
2720 <term>Typical use:</term>
2722 <para>Confuse log analysis, custom applications</para>
2727 <term>Effect:</term>
2730 Sends a user defined HTTP header to the web server.
2737 <!-- boolean, parameterized, Multi-value -->
2739 <para>Multi-value.</para>
2744 <term>Parameter:</term>
2747 Any string value is possible. Validity of the defined HTTP headers is not checked.
2748 It is recommended that you use the <quote><literal>X-</literal></quote> prefix
2758 This action may be specified multiple times, in order to define multiple
2759 headers. This is rarely needed for the typical user. If you don't know what
2760 <quote>HTTP headers</quote> are, you definitely don't need to worry about this
2764 Headers added by this action are not modified by other actions.
2770 <term>Example usage:</term>
2772 <screen># Add a DNT ("Do not track") header to all requests,
2773 # event to those that already have one.
2775 # This is just an example, not a recommendation.
2777 # There is no reason to believe that user-tracking websites care
2778 # about the DNT header and depending on the User-Agent, adding the
2779 # header may make user-tracking easier.
2780 {+add-header{DNT: 1}}
2788 <!-- ~~~~~ New section ~~~~~ -->
2789 <sect3 renderas="sect4" id="block">
2790 <title>block</title>
2794 <term>Typical use:</term>
2796 <para>Block ads or other unwanted content</para>
2801 <term>Effect:</term>
2804 Requests for URLs to which this action applies are blocked, i.e. the
2805 requests are trapped by &my-app; and the requested URL is never retrieved,
2806 but is answered locally with a substitute page or image, as determined by
2808 linkend="handle-as-image">handle-as-image</link></literal>,
2810 linkend="set-image-blocker">set-image-blocker</link></literal>, and
2812 linkend="handle-as-empty-document">handle-as-empty-document</link></literal> actions.
2820 <!-- boolean, parameterized, Multi-value -->
2822 <para>Parameterized.</para>
2827 <term>Parameter:</term>
2829 <para>A block reason that should be given to the user.</para>
2837 <application>Privoxy</application> sends a special <quote>BLOCKED</quote> page
2838 for requests to blocked pages. This page contains the block reason given as
2839 parameter, a link to find out why the block action applies, and a click-through
2840 to the blocked content (the latter only if the force feature is available and
2844 A very important exception occurs if <emphasis>both</emphasis>
2845 <literal>block</literal> and <literal><link linkend="handle-as-image">handle-as-image</link></literal>,
2846 apply to the same request: it will then be replaced by an image. If
2847 <literal><link linkend="set-image-blocker">set-image-blocker</link></literal>
2848 (see below) also applies, the type of image will be determined by its parameter,
2849 if not, the standard checkerboard pattern is sent.
2852 It is important to understand this process, in order
2853 to understand how <application>Privoxy</application> deals with
2854 ads and other unwanted content. Blocking is a core feature, and one
2855 upon which various other features depend.
2858 The <literal><link linkend="filter">filter</link></literal>
2859 action can perform a very similar task, by <quote>blocking</quote>
2860 banner images and other content through rewriting the relevant URLs in the
2861 document's HTML source, so they don't get requested in the first place.
2862 Note that this is a totally different technique, and it's easy to confuse the two.
2868 <term>Example usage (section):</term>
2871 {+block{No nasty stuff for you.}}
2872 # Block and replace with "blocked" page
2873 .nasty-stuff.example.com
2875 {+block{Doubleclick banners.} +handle-as-image}
2876 # Block and replace with image
2880 {+block{Layered ads.} +handle-as-empty-document}
2881 # Block and then ignore
2882 adserver.example.net/.*\.js$
2892 <!-- ~~~~~ New section ~~~~~ -->
2893 <sect3 renderas="sect4" id="change-x-forwarded-for">
2894 <title>change-x-forwarded-for</title>
2898 <term>Typical use:</term>
2900 <para>Improve privacy by not forwarding the source of the request in the HTTP headers.</para>
2905 <term>Effect:</term>
2908 Deletes the <quote>X-Forwarded-For:</quote> HTTP header from the client request,
2916 <!-- Boolean, Parameterized, Multi-value -->
2918 <para>Parameterized.</para>
2923 <term>Parameter:</term>
2927 <para><quote>block</quote> to delete the header.</para>
2931 <quote>add</quote> to create the header (or append
2932 the client's IP address to an already existing one).
2943 It is safe and recommended to use <literal>block</literal>.
2946 Forwarding the source address of the request may make
2947 sense in some multi-user setups but is also a privacy risk.
2952 <term>Example usage:</term>
2954 <screen>+change-x-forwarded-for{block}</screen>
2960 <!-- ~~~~~ New section ~~~~~ -->
2961 <sect3 renderas="sect4" id="client-header-filter">
2962 <title>client-header-filter</title>
2966 <term>Typical use:</term>
2969 Rewrite or remove single client headers.
2975 <term>Effect:</term>
2978 All client headers to which this action applies are filtered on-the-fly through
2979 the specified regular expression based substitutions.
2986 <!-- boolean, parameterized, Multi-value -->
2988 <para>Multi-value.</para>
2993 <term>Parameter:</term>
2996 The name of a client-header filter, as defined in one of the
2997 <link linkend="filter-file">filter files</link>.
3006 Client-header filters are applied to each header on its own, not to
3007 all at once. This makes it easier to diagnose problems, but on the downside
3008 you can't write filters that only change header x if header y's value is z.
3009 You can do that by using tags though.
3012 Client-header filters are executed after the other header actions have finished
3013 and use their output as input.
3016 If the request URI gets changed, &my-app; will detect that and use the new
3017 one. This can be used to rewrite the request destination behind the client's
3018 back, for example to specify a Tor exit relay for certain requests.
3021 Note that to change the destination host for
3022 <link linkend="HTTPS-INSPECTION">https-inspected</link>
3023 requests a protocol and host has to be added to the URI.
3026 If <link linkend="HTTPS-INSPECTION">https inspection</link>
3027 is enabled, the protocol can be downgraded from https to http
3028 but upgrading a request from http to https is currently not
3032 After detecting a rewrite, &my-app; does not update the actions
3033 used for the request based on the new host.
3036 Please refer to the <link linkend="filter-file">filter file chapter</link>
3037 to learn which client-header filters are available by default, and how to
3045 <term>Example usage (section):</term>
3048 # Hide Tor exit notation in Host and Referer Headers
3049 {+client-header-filter{hide-tor-exit-notation}}
3058 <!-- ~~~~~ New section ~~~~~ -->
3059 <sect3 renderas="sect4" id="client-body-filter">
3060 <title>client-body-filter</title>
3064 <term>Typical use:</term>
3067 Rewrite or remove client request body.
3073 <term>Effect:</term>
3076 All request bodies to which this action applies are filtered on-the-fly through
3077 the specified regular expression based substitutions.
3084 <!-- boolean, parameterized, Multi-value -->
3086 <para>Multi-value.</para>
3091 <term>Parameter:</term>
3094 The name of a client-body filter, as defined in one of the
3095 <link linkend="filter-file">filter files</link>.
3104 Please refer to the <link linkend="filter-file">filter file chapter</link>
3105 to learn how to create your own client-body filters.
3108 The distribution <filename>default.filter</filename> file contains a selection of
3109 client-body filters for example purposes.
3112 The amount of data that can be filtered is limited by the
3113 <literal><link linkend="buffer-limit">buffer-limit</link></literal>
3114 option in the main <link linkend="config">config file</link>. The
3115 default is 4096 KB (4 Megs). Once this limit is exceeded, the whole
3116 request body is passed through unfiltered.
3122 <term>Example usage (section):</term>
3125 # Remove "test" everywhere in the request body
3126 {+client-body-filter{remove-test}}
3136 <!-- ~~~~~ New section ~~~~~ -->
3137 <sect3 renderas="sect4" id="client-body-tagger">
3138 <title>client-body-tagger</title>
3142 <term>Typical use:</term>
3145 Block requests based on the content of the body data.
3151 <term>Effect:</term>
3154 Client request bodies to which this action applies are filtered on-the-fly through
3155 the specified regular expression based substitutions, the result is used as tag.
3162 <!-- boolean, parameterized, Multi-value -->
3164 <para>Multi-value.</para>
3169 <term>Parameter:</term>
3172 The name of a client-body tagger, as defined in one of the
3173 <link linkend="filter-file">filter files</link>.
3182 Please refer to the <link linkend="filter-file">filter file chapter</link>
3183 to learn how to create your own client-body tagger.
3186 Client-body taggers are applied to each request body on its own,
3187 and as the body isn't modified, each tagger "sees" the original.
3190 Chunk-encoded request bodies currently can't be tagged.
3191 Request bodies larger than the buffer-limit can't be tagged either.
3197 <term>Example usage (section):</term>
3200 # Apply blafasel tagger.
3201 {+client-body-tagger{blafasel}}
3204 # Block request based on the tag created by the blafasel tagger.
3205 {+block{Request body contains blafasel}}
3206 TAG:^content contains blafasel$
3215 <!-- ~~~~~ New section ~~~~~ -->
3216 <sect3 renderas="sect4" id="client-header-tagger">
3217 <title>client-header-tagger</title>
3221 <term>Typical use:</term>
3224 Block requests based on their headers.
3230 <term>Effect:</term>
3233 Client headers to which this action applies are filtered on-the-fly through
3234 the specified regular expression based substitutions, the result is used as
3242 <!-- boolean, parameterized, Multi-value -->
3244 <para>Multi-value.</para>
3249 <term>Parameter:</term>
3252 The name of a client-header tagger, as defined in one of the
3253 <link linkend="filter-file">filter files</link>.
3262 Client-header taggers are applied to each header on its own,
3263 and as the header isn't modified, each tagger <quote>sees</quote>
3267 Client-header taggers are the first actions that are executed
3268 and their tags can be used to control every other action.
3274 <term>Example usage (section):</term>
3277 # Tag every request with the User-Agent header
3278 {+client-header-tagger{user-agent}}
3281 # Tagging itself doesn't change the action
3282 # settings, sections with TAG patterns do:
3284 # If it's a download agent, use a different forwarding proxy,
3285 # show the real User-Agent and make sure resume works.
3286 {+forward-override{forward-socks5 10.0.0.2:2222 .} \
3287 -hide-if-modified-since \
3288 -overwrite-last-modified \
3293 TAG:^User-Agent: NetBSD-ftp/
3294 TAG:^User-Agent: Novell ZYPP Installer
3295 TAG:^User-Agent: RPM APT-HTTP/
3296 TAG:^User-Agent: fetch libfetch/
3297 TAG:^User-Agent: Ubuntu APT-HTTP/
3298 TAG:^User-Agent: MPlayer/
3302 # Tag all requests with the Range header set
3303 {+client-header-tagger{range-requests}}
3306 # Disable filtering for the tagged requests.
3308 # With filtering enabled Privoxy would remove the Range headers
3309 # to be able to filter the whole response. The downside is that
3310 # it prevents clients from resuming downloads or skipping over
3311 # parts of multimedia files.
3312 {-filter -deanimate-gifs}
3317 # Tag all requests with the client IP address
3319 # (Technically the client IP address isn't included in the
3320 # client headers but client-header taggers can set it anyway.
3321 # For details see the tagger in default.filter)
3322 {+client-header-tagger{client-ip-address}}
3325 # Change forwarding settings for requests coming from address 10.0.0.1
3326 {+forward-override{forward-socks5 127.0.1.2:2222 .}}
3327 TAG:^IP-ADDRESS: 10\.0\.0\.1$
3336 <!-- ~~~~~ New section ~~~~~ -->
3337 <sect3 renderas="sect4" id="content-type-overwrite">
3338 <title>content-type-overwrite</title>
3342 <term>Typical use:</term>
3344 <para>Stop useless download menus from popping up, or change the browser's rendering mode</para>
3349 <term>Effect:</term>
3352 Replaces the <quote>Content-Type:</quote> HTTP server header.
3359 <!-- Boolean, Parameterized, Multi-value -->
3361 <para>Parameterized.</para>
3366 <term>Parameter:</term>
3378 The <quote>Content-Type:</quote> HTTP server header is used by the
3379 browser to decide what to do with the document. The value of this
3380 header can cause the browser to open a download menu instead of
3381 displaying the document by itself, even if the document's format is
3382 supported by the browser.
3385 The declared content type can also affect which rendering mode
3386 the browser chooses. If XHTML is delivered as <quote>text/html</quote>,
3387 many browsers treat it as yet another broken HTML document.
3388 If it is send as <quote>application/xml</quote>, browsers with
3389 XHTML support will only display it, if the syntax is correct.
3392 If you see a web site that proudly uses XHTML buttons, but sets
3393 <quote>Content-Type: text/html</quote>, you can use &my-app;
3394 to overwrite it with <quote>application/xml</quote> and validate
3395 the web master's claim inside your XHTML-supporting browser.
3396 If the syntax is incorrect, the browser will complain loudly.
3399 You can also go the opposite direction: if your browser prints
3400 error messages instead of rendering a document falsely declared
3401 as XHTML, you can overwrite the content type with
3402 <quote>text/html</quote> and have it rendered as broken HTML document.
3405 By default <literal>content-type-overwrite</literal> only replaces
3406 <quote>Content-Type:</quote> headers that look like some kind of text.
3407 If you want to overwrite it unconditionally, you have to combine it with
3408 <literal><link linkend="force-text-mode">force-text-mode</link></literal>.
3409 This limitation exists for a reason, think twice before circumventing it.
3412 Most of the time it's easier to replace this action with a custom
3413 <literal><link linkend="server-header-filter">server-header filter</link></literal>.
3414 It allows you to activate it for every document of a certain site and it will still
3415 only replace the content types you aimed at.
3418 Of course you can apply <literal>content-type-overwrite</literal>
3419 to a whole site and then make URL based exceptions, but it's a lot
3420 more work to get the same precision.
3426 <term>Example usage (sections):</term>
3428 <screen># Check if www.example.net/ really uses valid XHTML
3429 { +content-type-overwrite{application/xml} }
3432 # but leave the content type unmodified if the URL looks like a style sheet
3433 {-content-type-overwrite}
3434 www.example.net/.*\.css$
3435 www.example.net/.*style
3443 <!-- ~~~~~ New section ~~~~~ -->
3444 <sect3 renderas="sect4" id="crunch-client-header">
3448 <title>crunch-client-header</title>
3452 <term>Typical use:</term>
3454 <para>Remove a client header <application>Privoxy</application> has no dedicated action for.</para>
3459 <term>Effect:</term>
3462 Deletes every header sent by the client that contains the string the user supplied as parameter.
3469 <!-- Boolean, Parameterized, Multi-value -->
3471 <para>Parameterized.</para>
3476 <term>Parameter:</term>
3488 This action allows you to block client headers for which no dedicated
3489 <application>Privoxy</application> action exists.
3490 <application>Privoxy</application> will remove every client header that
3491 contains the string you supplied as parameter.
3494 Regular expressions are <emphasis>not supported</emphasis> and you can't
3495 use this action to block different headers in the same request, unless
3496 they contain the same string.
3499 <literal>crunch-client-header</literal> is only meant for quick tests.
3500 If you have to block several different headers, or only want to modify
3501 parts of them, you should use a
3502 <literal><link linkend="client-header-filter">client-header filter</link></literal>.
3506 Don't block any header without understanding the consequences.
3513 <term>Example usage (section):</term>
3515 <screen># Block the non-existent "Privacy-Violation:" client header
3516 { +crunch-client-header{Privacy-Violation:} }
3525 <!-- ~~~~~ New section ~~~~~ -->
3526 <sect3 renderas="sect4" id="crunch-if-none-match">
3527 <title>crunch-if-none-match</title>
3533 <term>Typical use:</term>
3535 <para>Prevent yet another way to track the user's steps between sessions.</para>
3540 <term>Effect:</term>
3543 Deletes the <quote>If-None-Match:</quote> HTTP client header.
3550 <!-- Boolean, Parameterized, Multi-value -->
3552 <para>Boolean.</para>
3557 <term>Parameter:</term>
3569 Removing the <quote>If-None-Match:</quote> HTTP client header
3570 is useful for filter testing, where you want to force a real
3571 reload instead of getting status code <quote>304</quote> which
3572 would cause the browser to use a cached copy of the page.
3575 It is also useful to make sure the header isn't used as a cookie
3576 replacement (unlikely but possible).
3579 Blocking the <quote>If-None-Match:</quote> header shouldn't cause any
3580 caching problems, as long as the <quote>If-Modified-Since:</quote> header
3581 isn't blocked or missing as well.
3584 It is recommended to use this action together with
3585 <literal><link linkend="hide-if-modified-since">hide-if-modified-since</link></literal>
3587 <literal><link linkend="overwrite-last-modified">overwrite-last-modified</link></literal>.
3593 <term>Example usage (section):</term>
3595 <screen># Let the browser revalidate cached documents but don't
3596 # allow the server to use the revalidation headers for user tracking.
3597 {+hide-if-modified-since{-60} \
3598 +overwrite-last-modified{randomize} \
3599 +crunch-if-none-match}
3608 <!-- ~~~~~ New section ~~~~~ -->
3609 <sect3 renderas="sect4" id="crunch-incoming-cookies">
3610 <title>crunch-incoming-cookies</title>
3614 <term>Typical use:</term>
3617 Prevent the web server from setting HTTP cookies on your system
3623 <term>Effect:</term>
3626 Deletes any <quote>Set-Cookie:</quote> HTTP headers from server replies.
3633 <!-- Boolean, Parameterized, Multi-value -->
3635 <para>Boolean.</para>
3640 <term>Parameter:</term>
3652 This action is only concerned with <emphasis>incoming</emphasis> HTTP cookies. For
3653 <emphasis>outgoing</emphasis> HTTP cookies, use
3654 <literal><link linkend="crunch-outgoing-cookies">crunch-outgoing-cookies</link></literal>.
3655 Use <emphasis>both</emphasis> to disable HTTP cookies completely.
3658 It makes <emphasis>no sense at all</emphasis> to use this action in conjunction
3659 with the <literal><link linkend="session-cookies-only">session-cookies-only</link></literal> action,
3660 since it would prevent the session cookies from being set. See also
3661 <literal><link linkend="filter-content-cookies">filter-content-cookies</link></literal>.
3667 <term>Example usage:</term>
3669 <screen>+crunch-incoming-cookies</screen>
3676 <!-- ~~~~~ New section ~~~~~ -->
3677 <sect3 renderas="sect4" id="crunch-server-header">
3678 <title>crunch-server-header</title>
3684 <term>Typical use:</term>
3686 <para>Remove a server header <application>Privoxy</application> has no dedicated action for.</para>
3691 <term>Effect:</term>
3694 Deletes every header sent by the server that contains the string the user supplied as parameter.
3701 <!-- Boolean, Parameterized, Multi-value -->
3703 <para>Parameterized.</para>
3708 <term>Parameter:</term>
3720 This action allows you to block server headers for which no dedicated
3721 <application>Privoxy</application> action exists. <application>Privoxy</application>
3722 will remove every server header that contains the string you supplied as parameter.
3725 Regular expressions are <emphasis>not supported</emphasis> and you can't
3726 use this action to block different headers in the same request, unless
3727 they contain the same string.
3730 <literal>crunch-server-header</literal> is only meant for quick tests.
3731 If you have to block several different headers, or only want to modify
3732 parts of them, you should use a custom
3733 <literal><link linkend="server-header-filter">server-header filter</link></literal>.
3737 Don't block any header without understanding the consequences.
3744 <term>Example usage (section):</term>
3746 <screen># Crunch server headers that try to prevent caching
3747 { +crunch-server-header{no-cache} }
3756 <!-- ~~~~~ New section ~~~~~ -->
3757 <sect3 renderas="sect4" id="crunch-outgoing-cookies">
3758 <title>crunch-outgoing-cookies</title>
3762 <term>Typical use:</term>
3765 Prevent the web server from reading any HTTP cookies from your system
3771 <term>Effect:</term>
3774 Deletes any <quote>Cookie:</quote> HTTP headers from client requests.
3781 <!-- Boolean, Parameterized, Multi-value -->
3783 <para>Boolean.</para>
3788 <term>Parameter:</term>
3800 This action is only concerned with <emphasis>outgoing</emphasis> HTTP cookies. For
3801 <emphasis>incoming</emphasis> HTTP cookies, use
3802 <literal><link linkend="crunch-incoming-cookies">crunch-incoming-cookies</link></literal>.
3803 Use <emphasis>both</emphasis> to disable HTTP cookies completely.
3806 It makes <emphasis>no sense at all</emphasis> to use this action in conjunction
3807 with the <literal><link linkend="session-cookies-only">session-cookies-only</link></literal> action,
3808 since it would prevent the session cookies from being read.
3814 <term>Example usage:</term>
3816 <screen>+crunch-outgoing-cookies</screen>
3824 <!-- ~~~~~ New section ~~~~~ -->
3825 <sect3 renderas="sect4" id="deanimate-gifs">
3826 <title>deanimate-gifs</title>
3830 <term>Typical use:</term>
3832 <para>Stop those annoying, distracting animated GIF images.</para>
3837 <term>Effect:</term>
3840 De-animate GIF animations, i.e. reduce them to their first or last image.
3847 <!-- boolean, parameterized, Multi-value -->
3849 <para>Parameterized.</para>
3854 <term>Parameter:</term>
3857 <quote>last</quote> or <quote>first</quote>
3866 This will also shrink the images considerably (in bytes, not pixels!). If
3867 the option <quote>first</quote> is given, the first frame of the animation
3868 is used as the replacement. If <quote>last</quote> is given, the last
3869 frame of the animation is used instead, which probably makes more sense for
3870 most banner animations, but also has the risk of not showing the entire
3871 last frame (if it is only a delta to an earlier frame).
3874 You can safely use this action with patterns that will also match non-GIF
3875 objects, because no attempt will be made at anything that doesn't look like
3882 <term>Example usage:</term>
3884 <screen>+deanimate-gifs{last}</screen>
3891 <!-- ~~~~~ New section ~~~~~ -->
3892 <sect3 renderas="sect4" id="delay-response">
3893 <title>delay-response</title>
3897 <term>Typical use:</term>
3899 <para>Delay responses to the client to reduce the load</para>
3904 <term>Effect:</term>
3907 Delays responses to the client by sending the response in ca. 10 byte chunks.
3914 <!-- boolean, parameterized, Multi-value -->
3916 <para>Parameterized.</para>
3921 <term>Parameter:</term>
3924 <quote>Number of milliseconds</quote>
3933 Sometimes when JavaScript code is used to fetch advertisements
3934 it doesn't respect Privoxy's blocks and retries to fetch the
3935 same resource again causing unnecessary load on the client.
3938 This action delays responses to the client and can be combined
3939 with <literal><link linkend="block">blocks</link></literal>
3940 to slow down the JavaScript code, thus reducing
3941 the load on the client.
3944 When used without <literal><link linkend="block">blocks</link></literal>
3945 the action can also be used to simulate a slow internet connection.
3951 <term>Example usage:</term>
3953 <screen>+delay-response{100}</screen>
3960 <!-- ~~~~~ New section ~~~~~ -->
3961 <sect3 renderas="sect4" id="downgrade-http-version">
3962 <title>downgrade-http-version</title>
3966 <term>Typical use:</term>
3968 <para>Work around (very rare) problems with HTTP/1.1</para>
3973 <term>Effect:</term>
3976 Downgrades HTTP/1.1 client requests and server replies to HTTP/1.0.
3983 <!-- boolean, parameterized, Multi-value -->
3985 <para>Boolean.</para>
3990 <term>Parameter:</term>
4002 This is a left-over from the time when <application>Privoxy</application>
4003 didn't support important HTTP/1.1 features well. It is left here for the
4004 unlikely case that you experience HTTP/1.1-related problems with some server
4008 Note that enabling this action is only a workaround. It should not
4009 be enabled for sites that work without it. While it shouldn't break
4010 any pages, it has an (usually negative) performance impact.
4013 If you come across a site where enabling this action helps, please report it,
4014 so the cause of the problem can be analyzed. If the problem turns out to be
4015 caused by a bug in <application>Privoxy</application> it should be
4016 fixed so the following release works without the work around.
4022 <term>Example usage (section):</term>
4024 <screen>{+downgrade-http-version}
4025 problem-host.example.com</screen>
4033 <!-- ~~~~~ New section ~~~~~ -->
4034 <sect3 renderas="sect4" id="external-filter">
4035 <title>external-filter</title>
4039 <term>Typical use:</term>
4041 <para>Modify content using a programming language of your choice.</para>
4046 <term>Effect:</term>
4049 All instances of text-based type, most notably HTML and JavaScript, to which
4050 this action applies, can be filtered on-the-fly through the specified external
4052 By default plain text documents are exempted from filtering, because web
4053 servers often use the <literal>text/plain</literal> MIME type for all files
4054 whose type they don't know.)
4061 <!-- boolean, parameterized, Multi-value -->
4063 <para>Multi-value.</para>
4068 <term>Parameter:</term>
4071 The name of an external content filter, as defined in the
4072 <link linkend="filter-file">filter file</link>.
4073 External filters can be defined in one or more files as defined by the
4074 <literal><link linkend="filterfile">filterfile</link></literal>
4075 option in the <link linkend="config">config file</link>.
4078 When used in its negative form,
4079 and without parameters, <emphasis>all</emphasis> filtering with external
4080 filters is completely disabled.
4089 External filters are scripts or programs that can modify the content in
4090 case common <literal><link linkend="filter">filters</link></literal>
4091 aren't powerful enough. With the exception that this action doesn't
4092 use pcrs-based filters, the notes in the
4093 <literal><link linkend="filter">filter</link></literal> section apply.
4097 Currently external filters are executed with &my-app;'s privileges.
4098 Only use external filters you understand and trust.
4102 This feature is experimental, the <literal><link
4103 linkend="external-filter-syntax">syntax</link></literal>
4104 may change in the future.
4111 <term>Example usage:</term>
4113 <screen>+external-filter{fancy-filter}</screen>
4119 <!-- ~~~~~ New section ~~~~~ -->
4120 <sect3 renderas="sect4" id="fast-redirects">
4121 <title>fast-redirects</title>
4125 <term>Typical use:</term>
4127 <para>Fool some click-tracking scripts and speed up indirect links.</para>
4132 <term>Effect:</term>
4135 Detects redirection URLs and redirects the browser without contacting
4136 the redirection server first.
4143 <!-- boolean, parameterized, Multi-value -->
4145 <para>Parameterized.</para>
4150 <term>Parameter:</term>
4155 <quote>simple-check</quote> to just search for the string <quote>http://</quote>
4156 to detect redirection URLs.
4161 <quote>check-decoded-url</quote> to decode URLs (if necessary) before searching
4162 for redirection URLs.
4173 Many sites, like yahoo.com, don't just link to other sites. Instead, they
4174 will link to some script on their own servers, giving the destination as a
4175 parameter, which will then redirect you to the final target. URLs
4176 resulting from this scheme typically look like:
4177 <quote>http://www.example.org/click-tracker.cgi?target=http%3a//www.example.net/</quote>.
4180 Sometimes, there are even multiple consecutive redirects encoded in the
4181 URL. These redirections via scripts make your web browsing more traceable,
4182 since the server from which you follow such a link can see where you go
4183 to. Apart from that, valuable bandwidth and time is wasted, while your
4184 browser asks the server for one redirect after the other. Plus, it feeds
4188 This feature is currently not very smart and is scheduled for improvement.
4189 If it is enabled by default, you will have to create some exceptions to
4190 this action. It can lead to failures in several ways:
4193 Not every URLs with other URLs as parameters is evil.
4194 Some sites offer a real service that requires this information to work.
4195 For example a validation service needs to know, which document to validate.
4196 <literal>fast-redirects</literal> assumes that every URL parameter that
4197 looks like another URL is a redirection target, and will always redirect to
4198 the last one. Most of the time the assumption is correct, but if it isn't,
4199 the user gets redirected anyway.
4202 Another failure occurs if the URL contains other parameters after the URL parameter.
4204 <quote>http://www.example.org/?redirect=http%3a//www.example.net/&foo=bar</quote>.
4205 contains the redirection URL <quote>http://www.example.net/</quote>,
4206 followed by another parameter. <literal>fast-redirects</literal> doesn't know that
4207 and will cause a redirect to <quote>http://www.example.net/&foo=bar</quote>.
4208 Depending on the target server configuration, the parameter will be silently ignored
4209 or lead to a <quote>page not found</quote> error. You can prevent this problem by
4210 first using the <literal><link linkend="redirect">redirect</link></literal> action
4211 to remove the last part of the URL, but it requires a little effort.
4214 To detect a redirection URL, <literal>fast-redirects</literal> only
4215 looks for the string <quote>http://</quote>, either in plain text
4216 (invalid but often used) or encoded as <quote>http%3a//</quote>.
4217 Some sites use their own URL encoding scheme, encrypt the address
4218 of the target server or replace it with a database id. In these cases
4219 <literal>fast-redirects</literal> is fooled and the request reaches the
4220 redirection server where it probably gets logged.
4226 <term>Example usage:</term>
4229 { +fast-redirects{simple-check} }
4232 { +fast-redirects{check-decoded-url} }
4233 another.example.com/testing
4242 <!-- ~~~~~ New section ~~~~~ -->
4243 <sect3 renderas="sect4" id="filter">
4244 <title>filter</title>
4248 <term>Typical use:</term>
4250 <para>Get rid of HTML and JavaScript annoyances, banner advertisements (by size),
4251 do fun text replacements, add personalized effects, etc.</para>
4256 <term>Effect:</term>
4259 All instances of text-based type, most notably HTML and JavaScript, to which
4260 this action applies, can be filtered on-the-fly through the specified regular
4261 expression based substitutions. (Note: as of version 3.0.3 plain text documents
4262 are exempted from filtering, because web servers often use the
4263 <literal>text/plain</literal> MIME type for all files whose type they don't know.)
4270 <!-- boolean, parameterized, Multi-value -->
4272 <para>Multi-value.</para>
4277 <term>Parameter:</term>
4280 The name of a content filter, as defined in the <link linkend="filter-file">filter file</link>.
4281 Filters can be defined in one or more files as defined by the
4282 <literal><link linkend="filterfile">filterfile</link></literal>
4283 option in the <link linkend="config">config file</link>.
4284 <filename>default.filter</filename> is the collection of filters
4285 supplied by the developers. Locally defined filters should go
4286 in their own file, such as <filename>user.filter</filename>.
4289 When used in its negative form,
4290 and without parameters, <emphasis>all</emphasis> filtering is completely disabled.
4299 For your convenience, there are a number of pre-defined filters available
4300 in the distribution filter file that you can use. See the examples below for
4304 Filtering requires buffering the page content, which may appear to
4305 slow down page rendering since nothing is displayed until all content has
4306 passed the filters. (The total time until the page is completely rendered
4307 doesn't change much, but it may be perceived as slower since the page is
4308 not incrementally displayed.)
4309 This effect will be more noticeable on slower connections.
4312 <quote>Rolling your own</quote>
4313 filters requires a knowledge of
4314 <ulink url="https://en.wikipedia.org/wiki/Regular_expressions"><quote>Regular
4315 Expressions</quote></ulink> and
4316 <ulink url="https://en.wikipedia.org/wiki/Html"><quote>HTML</quote></ulink>.
4317 This is very powerful feature, and potentially very intrusive.
4318 Filters should be used with caution, and where an equivalent
4319 <quote>action</quote> is not available.
4322 The amount of data that can be filtered is limited by the
4323 <literal><link linkend="buffer-limit">buffer-limit</link></literal>
4324 option in the main <link linkend="config">config file</link>. The
4325 default is 4096 KB (4 Megs). Once this limit is exceeded, the buffered
4326 data, and all pending data, is passed through unfiltered.
4329 Inappropriate MIME types, such as zipped files, are not filtered at all.
4330 (Again, only text-based types except plain text). Encrypted SSL data
4331 (from HTTPS servers) cannot be filtered either, since this would violate
4332 the integrity of the secure transaction. In some situations it might
4333 be necessary to protect certain text, like source code, from filtering
4334 by defining appropriate <literal>-filter</literal> exceptions.
4337 Compressed content can't be filtered either, but if &my-app;
4338 is compiled with zlib support and a supported compression algorithm
4339 is used (gzip or deflate), &my-app; can first decompress the content
4343 If you use a &my-app; version without zlib support, but want filtering to work on
4344 as much documents as possible, even those that would normally be sent compressed,
4345 you must use the <literal><link linkend="prevent-compression">prevent-compression</link></literal>
4346 action in conjunction with <literal>filter</literal>.
4349 Content filtering can achieve some of the same effects as the
4350 <literal><link linkend="block">block</link></literal>
4351 action, i.e. it can be used to block ads and banners. But the mechanism
4352 works quite differently. One effective use, is to block ad banners
4353 based on their size (see below), since many of these seem to be somewhat
4357 <link linkend="contact">Feedback</link> with suggestions for new or
4358 improved filters is particularly welcome!
4361 The below list has only the names and a one-line description of each
4362 predefined filter. There are <link linkend="predefined-filters">more
4363 verbose explanations</link> of what these filters do in the <link
4364 linkend="filter-file">filter file chapter</link>.
4370 <term>Example usage (with filters from the distribution <filename>default.filter</filename> file).
4371 See <link linkend="PREDEFINED-FILTERS">the Predefined Filters section</link> for
4372 more explanation on each:</term>
4375 <anchor id="filter-js-annoyances">
4377 <screen>+filter{js-annoyances} # Get rid of particularly annoying JavaScript abuse.</screen>
4379 <anchor id="filter-js-events">
4381 <screen>+filter{js-events} # Kill JavaScript event bindings and timers (Radically destructive! Only for extra nasty sites).</screen>
4383 <anchor id="filter-html-annoyances">
4385 <screen>+filter{html-annoyances} # Get rid of particularly annoying HTML abuse.</screen>
4387 <anchor id="filter-content-cookies">
4389 <screen>+filter{content-cookies} # Kill cookies that come in the HTML or JS content.</screen>
4391 <anchor id="filter-refresh-tags">
4393 <screen>+filter{refresh-tags} # Kill automatic refresh tags if refresh time is larger than 9 seconds.</screen>
4395 <anchor id="filter-unsolicited-popups">
4397 <screen>+filter{unsolicited-popups} # Disable only unsolicited pop-up windows.</screen>
4399 <anchor id="filter-all-popups">
4401 <screen>+filter{all-popups} # Kill all popups in JavaScript and HTML.</screen>
4403 <anchor id="filter-img-reorder">
4405 <screen>+filter{img-reorder} # Reorder attributes in <img> tags to make the banners-by-* filters more effective.</screen>
4407 <anchor id="filter-banners-by-size">
4409 <screen>+filter{banners-by-size} # Kill banners by size.</screen>
4411 <anchor id="filter-banners-by-link">
4413 <screen>+filter{banners-by-link} # Kill banners by their links to known clicktrackers.</screen>
4415 <anchor id="filter-webbugs">
4417 <screen>+filter{webbugs} # Squish WebBugs (1x1 invisible GIFs used for user tracking).</screen>
4419 <anchor id="filter-tiny-textforms">
4421 <screen>+filter{tiny-textforms} # Extend those tiny textareas up to 40x80 and kill the hard wrap.</screen>
4423 <anchor id="filter-jumping-windows">
4425 <screen>+filter{jumping-windows} # Prevent windows from resizing and moving themselves.</screen>
4427 <anchor id="filter-frameset-borders">
4429 <screen>+filter{frameset-borders} # Give frames a border and make them resizable.</screen>
4431 <anchor id="filter-iframes">
4433 <screen>+filter{iframes} # Removes all detected iframes. Should only be enabled for individual sites.</screen>
4435 <anchor id="filter-demoronizer">
4437 <screen>+filter{demoronizer} # Fix MS's non-standard use of standard charsets.</screen>
4439 <anchor id="filter-shockwave-flash">
4441 <screen>+filter{shockwave-flash} # Kill embedded Shockwave Flash objects.</screen>
4443 <anchor id="filter-quicktime-kioskmode">
4445 <screen>+filter{quicktime-kioskmode} # Make Quicktime movies saveable.</screen>
4447 <anchor id="filter-fun">
4449 <screen>+filter{fun} # Text replacements for subversive browsing fun!</screen>
4451 <anchor id="filter-crude-parental">
4453 <screen>+filter{crude-parental} # Crude parental filtering. Note that this filter doesn't work reliably.</screen>
4455 <anchor id="filter-ie-exploits">
4457 <screen>+filter{ie-exploits} # Disable some known Internet Explorer bug exploits.</screen>
4459 <anchor id="filter-site-specifics">
4461 <screen>+filter{site-specifics} # Cure for site-specific problems. Don't apply generally!</screen>
4463 <anchor id="filter-no-ping">
4465 <screen>+filter{no-ping} # Removes non-standard ping attributes in <a> and <area> tags.</screen>
4467 <anchor id="filter-bundeswehr.de">
4469 <screen>+filter{bundeswehr.de} # Hide the cookie and privacy info banner on bundeswehr.de.</screen>
4471 <anchor id="filter-github">
4473 <screen>+filter{github} # Removes the annoying "Sign-Up" banner and the Cookie disclaimer.</screen>
4475 <anchor id="filter-google">
4477 <screen>+filter{google} # CSS-based block for Google text ads. Also removes a width limitation and the toolbar advertisement.</screen>
4479 <anchor id="filter-imdb">
4481 <screen>+filter{imdb} # Removes some ads on IMDb.</screen>
4483 <anchor id="filter-yahoo">
4485 <screen>+filter{yahoo} # CSS-based block for Yahoo text ads. Also removes a width limitation.</screen>
4487 <anchor id="filter-msn">
4489 <screen>+filter{msn} # CSS-based block for MSN text ads. Also removes tracking URLs and a width limitation.</screen>
4491 <anchor id="filter-blogspot">
4493 <screen>+filter{blogspot} # Cleans up some Blogspot blogs. Read the fine print before using this.</screen>
4495 <anchor id="filter-sourceforge">
4497 <screen>+filter{sourceforge} # Reduces the amount of ads for proprietary software on SourceForge.</screen>
4504 <!-- ~~~~~ New section ~~~~~ -->
4505 <sect3 renderas="sect4" id="force-text-mode">
4506 <title>force-text-mode</title>
4512 <term>Typical use:</term>
4514 <para>Force <application>Privoxy</application> to treat a document as if it was in some kind of <emphasis>text</emphasis> format. </para>
4519 <term>Effect:</term>
4522 Declares a document as text, even if the <quote>Content-Type:</quote> isn't detected as such.
4529 <!-- Boolean, Parameterized, Multi-value -->
4531 <para>Boolean.</para>
4536 <term>Parameter:</term>
4548 As explained <literal><link linkend="filter">above</link></literal>,
4549 <application>Privoxy</application> tries to only filter files that are
4550 in some kind of text format. The same restrictions apply to
4551 <literal><link linkend="content-type-overwrite">content-type-overwrite</link></literal>.
4552 <literal>force-text-mode</literal> declares a document as text,
4553 without looking at the <quote>Content-Type:</quote> first.
4557 Think twice before activating this action. Filtering binary data
4558 with regular expressions can cause file damage.
4565 <term>Example usage:</term>
4576 <!-- ~~~~~ New section ~~~~~ -->
4577 <sect3 renderas="sect4" id="forward-override">
4578 <title>forward-override</title>
4584 <term>Typical use:</term>
4586 <para>Change the forwarding settings based on User-Agent or request origin</para>
4591 <term>Effect:</term>
4594 Overrules the forward directives in the configuration file.
4601 <!-- Boolean, Parameterized, Multi-value -->
4603 <para>Parameterized.</para>
4608 <term>Parameter:</term>
4612 <para><quote>forward .</quote> to use a direct connection without any additional proxies.</para>
4616 <quote>forward 127.0.0.1:8123</quote> to use the HTTP proxy listening at 127.0.0.1 port 8123.
4621 <quote>forward-socks4a 127.0.0.1:9050 .</quote> to use the socks4a proxy listening at
4622 127.0.0.1 port 9050. Replace <quote>forward-socks4a</quote> with <quote>forward-socks4</quote>
4623 to use a socks4 connection (with local DNS resolution) instead, use <quote>forward-socks5</quote>
4624 for socks5 connections (with remote DNS resolution).
4629 <quote>forward-socks4a 127.0.0.1:9050 proxy.example.org:8000</quote> to use the socks4a proxy
4630 listening at 127.0.0.1 port 9050 to reach the HTTP proxy listening at proxy.example.org port 8000.
4631 Replace <quote>forward-socks4a</quote> with <quote>forward-socks4</quote> to use a socks4 connection
4632 (with local DNS resolution) instead, use <quote>forward-socks5</quote>
4633 for socks5 connections (with remote DNS resolution).
4638 <quote>forward-webserver 127.0.0.1:80</quote> to use the HTTP
4639 server listening at 127.0.0.1 port 80 without adjusting the
4643 This makes it more convenient to use Privoxy to make
4644 existing websites available as onion services as well.
4647 Many websites serve content with hardcoded URLs and
4648 can't be easily adjusted to change the domain based
4649 on the one used by the client.
4652 Putting Privoxy between Tor and the webserver (or an stunnel
4653 that forwards to the webserver) allows to rewrite headers and
4654 content to make client and server happy at the same time.
4657 Using Privoxy for webservers that are only reachable through
4658 onion addresses and whose location is supposed to be secret
4659 is not recommended and should not be necessary anyway.
4670 This action takes parameters similar to the
4671 <link linkend="forwarding">forward</link> directives in the configuration
4672 file, but without the URL pattern. It can be used as replacement, but normally it's only
4673 used in cases where matching based on the request URL isn't sufficient.
4677 Please read the description for the <link linkend="forwarding">forward</link> directives before
4678 using this action. Forwarding to the wrong people will reduce your privacy and increase the
4679 chances of man-in-the-middle attacks.
4682 If the ports are missing or invalid, default values will be used. This might change
4683 in the future and you shouldn't rely on it. Otherwise incorrect syntax causes Privoxy
4684 to exit. Due to design limitations, invalid parameter syntax isn't detected until the
4685 action is used the first time.
4688 Use the <ulink url="http://config.privoxy.org/show-url-info">show-url-info CGI page</ulink>
4689 to verify that your forward settings do what you thought the do.
4696 <term>Example usage:</term>
4699 # Use an ssh tunnel for requests previously tagged as
4700 # <quote>User-Agent: fetch libfetch/2.0</quote> and make sure
4701 # resuming downloads continues to work.
4703 # This way you can continue to use Tor for your normal browsing,
4704 # without overloading the Tor network with your FreeBSD ports updates
4705 # or downloads of bigger files like ISOs.
4707 # Note that HTTP headers are easy to fake and therefore their
4708 # values are as (un)trustworthy as your clients and users.
4709 {+forward-override{forward-socks5 10.0.0.2:2222 .} \
4710 -hide-if-modified-since \
4711 -overwrite-last-modified \
4713 TAG:^User-Agent: fetch libfetch/2\.0$
4721 <!-- ~~~~~ New section ~~~~~ -->
4722 <sect3 renderas="sect4" id="handle-as-empty-document">
4723 <title>handle-as-empty-document</title>
4729 <term>Typical use:</term>
4731 <para>Mark URLs that should be replaced by empty documents <emphasis>if they get blocked</emphasis></para>
4736 <term>Effect:</term>
4739 This action alone doesn't do anything noticeable. It just marks URLs.
4740 If the <literal><link linkend="block">block</link></literal> action <emphasis>also applies</emphasis>,
4741 the presence or absence of this mark decides whether an HTML <quote>BLOCKED</quote>
4742 page, or an empty document will be sent to the client as a substitute for the blocked content.
4743 The <emphasis>empty</emphasis> document isn't literally empty, but actually contains a single space.
4750 <!-- Boolean, Parameterized, Multi-value -->
4752 <para>Boolean.</para>
4757 <term>Parameter:</term>
4769 Some browsers complain about syntax errors if JavaScript documents
4770 are blocked with <application>Privoxy's</application>
4771 default HTML page; this option can be used to silence them.
4772 And of course this action can also be used to eliminate the &my-app;
4773 BLOCKED message in frames.
4776 The content type for the empty document can be specified with
4777 <literal><link linkend="content-type-overwrite">content-type-overwrite{}</link></literal>,
4778 but usually this isn't necessary.
4784 <term>Example usage:</term>
4786 <screen># Block all documents on example.org that end with ".js",
4787 # but send an empty document instead of the usual HTML message.
4788 {+block{Blocked JavaScript} +handle-as-empty-document}
4797 <!-- ~~~~~ New section ~~~~~ -->
4798 <sect3 renderas="sect4" id="handle-as-image">
4799 <title>handle-as-image</title>
4803 <term>Typical use:</term>
4805 <para>Mark URLs as belonging to images (so they'll be replaced by images <emphasis>if they do get blocked</emphasis>, rather than HTML pages)</para>
4810 <term>Effect:</term>
4813 This action alone doesn't do anything noticeable. It just marks URLs as images.
4814 If the <literal><link linkend="block">block</link></literal> action <emphasis>also applies</emphasis>,
4815 the presence or absence of this mark decides whether an HTML <quote>blocked</quote>
4816 page, or a replacement image (as determined by the <literal><link
4817 linkend="set-image-blocker">set-image-blocker</link></literal> action) will be sent to the
4818 client as a substitute for the blocked content.
4825 <!-- Boolean, Parameterized, Multi-value -->
4827 <para>Boolean.</para>
4832 <term>Parameter:</term>
4844 The below generic example section is actually part of <filename>default.action</filename>.
4845 It marks all URLs with well-known image file name extensions as images and should
4849 Users will probably only want to use the handle-as-image action in conjunction with
4850 <literal><link linkend="block">block</link></literal>, to block sources of banners, whose URLs don't
4851 reflect the file type, like in the second example section.
4854 Note that you cannot treat HTML pages as images in most cases. For instance, (in-line) ad
4855 frames require an HTML page to be sent, or they won't display properly.
4856 Forcing <literal>handle-as-image</literal> in this situation will not replace the
4857 ad frame with an image, but lead to error messages.
4863 <term>Example usage (sections):</term>
4865 <screen># Generic image extensions:
4868 /.*\.(gif|jpg|jpeg|png|bmp|ico)$
4870 # These don't look like images, but they're banners and should be
4871 # blocked as images:
4873 {+block{Nasty banners.} +handle-as-image}
4874 nasty-banner-server.example.com/junk.cgi\?output=trash
4882 <!-- ~~~~~ New section ~~~~~ -->
4883 <sect3 renderas="sect4" id="hide-accept-language">
4884 <title>hide-accept-language</title>
4890 <term>Typical use:</term>
4892 <para>Pretend to use different language settings.</para>
4897 <term>Effect:</term>
4900 Deletes or replaces the <quote>Accept-Language:</quote> HTTP header in client requests.
4907 <!-- Boolean, Parameterized, Multi-value -->
4909 <para>Parameterized.</para>
4914 <term>Parameter:</term>
4917 Keyword: <quote>block</quote>, or any user defined value.
4926 Faking the browser's language settings can be useful to make a
4927 foreign User-Agent set with
4928 <literal><link linkend="hide-user-agent">hide-user-agent</link></literal>
4932 However some sites with content in different languages check the
4933 <quote>Accept-Language:</quote> to decide which one to take by default.
4934 Sometimes it isn't possible to later switch to another language without
4935 changing the <quote>Accept-Language:</quote> header first.
4938 Therefore it's a good idea to either only change the
4939 <quote>Accept-Language:</quote> header to languages you understand,
4940 or to languages that aren't wide spread.
4943 Before setting the <quote>Accept-Language:</quote> header
4944 to a rare language, you should consider that it helps to
4945 make your requests unique and thus easier to trace.
4946 If you don't plan to change this header frequently,
4947 you should stick to a common language.
4953 <term>Example usage (section):</term>
4955 <screen># Pretend to use Canadian language settings.
4956 {+hide-accept-language{en-ca} \
4957 +hide-user-agent{Mozilla/5.0 (X11; U; OpenBSD i386; en-CA; rv:1.8.0.4) Gecko/20060628 Firefox/1.5.0.4} \
4967 <!-- ~~~~~ New section ~~~~~ -->
4968 <sect3 renderas="sect4" id="hide-content-disposition">
4969 <title>hide-content-disposition</title>
4975 <term>Typical use:</term>
4977 <para>Prevent download menus for content you prefer to view inside the browser.</para>
4982 <term>Effect:</term>
4985 Deletes or replaces the <quote>Content-Disposition:</quote> HTTP header set by some servers.
4992 <!-- Boolean, Parameterized, Multi-value -->
4994 <para>Parameterized.</para>
4999 <term>Parameter:</term>
5002 Keyword: <quote>block</quote>, or any user defined value.
5011 Some servers set the <quote>Content-Disposition:</quote> HTTP header for
5012 documents they assume you want to save locally before viewing them.
5013 The <quote>Content-Disposition:</quote> header contains the file name
5014 the browser is supposed to use by default.
5017 In most browsers that understand this header, it makes it impossible to
5018 <emphasis>just view</emphasis> the document, without downloading it first,
5019 even if it's just a simple text file or an image.
5022 Removing the <quote>Content-Disposition:</quote> header helps
5023 to prevent this annoyance, but some browsers additionally check the
5024 <quote>Content-Type:</quote> header, before they decide if they can
5025 display a document without saving it first. In these cases, you have
5026 to change this header as well, before the browser stops displaying
5030 It is also possible to change the server's file name suggestion
5031 to another one, but in most cases it isn't worth the time to set
5035 This action will probably be removed in the future,
5036 use server-header filters instead.
5042 <term>Example usage:</term>
5045 # Disarm the download link in Sourceforge's patch tracker
5047 +content-type-overwrite{text/plain} \
5048 +hide-content-disposition{block} \
5050 .sourceforge.net/tracker/download\.php
5058 <!-- ~~~~~ New section ~~~~~ -->
5059 <sect3 renderas="sect4" id="hide-if-modified-since">
5060 <title>hide-if-modified-since</title>
5066 <term>Typical use:</term>
5068 <para>Prevent yet another way to track the user's steps between sessions.</para>
5073 <term>Effect:</term>
5076 Deletes the <quote>If-Modified-Since:</quote> HTTP client header or modifies its value.
5083 <!-- Boolean, Parameterized, Multi-value -->
5085 <para>Parameterized.</para>
5090 <term>Parameter:</term>
5093 Keyword: <quote>block</quote>, or a user defined value that specifies a range of hours.
5102 Removing this header is useful for filter testing, where you want to force a real
5103 reload instead of getting status code <quote>304</quote>, which would cause the
5104 browser to use a cached copy of the page.
5107 Instead of removing the header, <literal>hide-if-modified-since</literal> can
5108 also add or subtract a random amount of time to/from the header's value.
5109 You specify a range of minutes where the random factor should be chosen from and
5110 <application>Privoxy</application> does the rest. A negative value means
5111 subtracting, a positive value adding.
5114 Randomizing the value of the <quote>If-Modified-Since:</quote> makes
5115 it less likely that the server can use the time as a cookie replacement,
5116 but you will run into caching problems if the random range is too high.
5119 It is a good idea to only use a small negative value and let
5120 <literal><link linkend="overwrite-last-modified">overwrite-last-modified</link></literal>
5121 handle the greater changes.
5124 It is also recommended to use this action together with
5125 <literal><link linkend="crunch-if-none-match">crunch-if-none-match</link></literal>,
5126 otherwise it's more or less pointless.
5132 <term>Example usage (section):</term>
5134 <screen># Let the browser revalidate but make tracking based on the time less likely.
5135 {+hide-if-modified-since{-60} \
5136 +overwrite-last-modified{randomize} \
5137 +crunch-if-none-match}
5145 <!-- ~~~~~ New section ~~~~~ -->
5146 <sect3 renderas="sect4" id="hide-from-header">
5147 <title>hide-from-header</title>
5151 <term>Typical use:</term>
5153 <para>Keep your (old and ill) browser from telling web servers your email address</para>
5158 <term>Effect:</term>
5161 Deletes any existing <quote>From:</quote> HTTP header, or replaces it with the
5169 <!-- Boolean, Parameterized, Multi-value -->
5171 <para>Parameterized.</para>
5176 <term>Parameter:</term>
5179 Keyword: <quote>block</quote>, or any user defined value.
5188 The keyword <quote>block</quote> will completely remove the header
5189 (not to be confused with the <literal><link linkend="block">block</link></literal>
5193 Alternately, you can specify any value you prefer to be sent to the web
5194 server. If you do, it is a matter of fairness not to use any address that
5195 is actually used by a real person.
5198 This action is rarely needed, as modern web browsers don't send
5199 <quote>From:</quote> headers anymore.
5205 <term>Example usage:</term>
5207 <screen>+hide-from-header{block}</screen>
5209 <screen>+hide-from-header{spam-me-senseless@sittingduck.example.com}</screen>
5216 <!-- ~~~~~ New section ~~~~~ -->
5217 <sect3 renderas="sect4" id="hide-referrer">
5218 <title>hide-referrer</title>
5219 <anchor id="hide-referer">
5222 <term>Typical use:</term>
5224 <para>Conceal which link you followed to get to a particular site</para>
5229 <term>Effect:</term>
5232 Deletes the <quote>Referer:</quote> (sic) HTTP header from the client request,
5233 or replaces it with a forged one.
5240 <!-- Boolean, Parameterized, Multi-value -->
5242 <para>Parameterized.</para>
5247 <term>Parameter:</term>
5251 <para><quote>conditional-block</quote> to delete the header completely if the host has changed.</para>
5254 <para><quote>conditional-forge</quote> to forge the header if the host has changed.</para>
5257 <para><quote>block</quote> to delete the header unconditionally.</para>
5260 <para><quote>forge</quote> to pretend to be coming from the homepage of the server we are talking to.</para>
5263 <para>Any other string to set a user defined referrer.</para>
5273 <literal>conditional-block</literal> is the only parameter,
5274 that isn't easily detected in the server's log file. If it blocks the
5275 referrer, the request will look like the visitor used a bookmark or
5276 typed in the address directly.
5279 Leaving the referrer unmodified for requests on the same host
5280 allows the server owner to see the visitor's <quote>click path</quote>,
5281 but in most cases she could also get that information by comparing
5282 other parts of the log file: for example the User-Agent if it isn't
5283 a very common one, or the user's IP address if it doesn't change between
5287 Always blocking the referrer, or using a custom one, can lead to
5288 failures on servers that check the referrer before they answer any
5289 requests, in an attempt to prevent their content from being
5290 embedded or linked to elsewhere.
5293 Both <literal>conditional-block</literal> and <literal>forge</literal>
5294 will work with referrer checks, as long as content and valid referring page
5295 are on the same host. Most of the time that's the case.
5298 <literal>hide-referer</literal> is an alternate spelling of
5299 <literal>hide-referrer</literal> and the two can be can be freely
5300 substituted with each other. (<quote>referrer</quote> is the
5301 correct English spelling, however the HTTP specification has a bug - it
5302 requires it to be spelled as <quote>referer</quote>.)
5308 <term>Example usage:</term>
5310 <screen>+hide-referrer{forge}</screen>
5312 <screen>+hide-referrer{http://www.yahoo.com/}</screen>
5319 <!-- ~~~~~ New section ~~~~~ -->
5320 <sect3 renderas="sect4" id="hide-user-agent">
5321 <title>hide-user-agent</title>
5325 <term>Typical use:</term>
5327 <para>Try to conceal your type of browser and client operating system</para>
5332 <term>Effect:</term>
5335 Replaces the value of the <quote>User-Agent:</quote> HTTP header
5336 in client requests with the specified value.
5343 <!-- Boolean, Parameterized, Multi-value -->
5345 <para>Parameterized.</para>
5350 <term>Parameter:</term>
5353 Any user-defined string.
5363 This can lead to problems on web sites that depend on looking at this header in
5364 order to customize their content for different browsers (which, by the
5365 way, is <emphasis>NOT</emphasis> the right thing to do: good web sites
5366 work browser-independently).
5370 Using this action in multi-user setups or wherever different types of
5371 browsers will access the same <application>Privoxy</application> is
5372 <emphasis>not recommended</emphasis>. In single-user, single-browser
5373 setups, you might use it to delete your OS version information from
5374 the headers, because it is an invitation to exploit known bugs for your
5375 OS. It is also occasionally useful to forge this in order to access
5376 sites that won't let you in otherwise (though there may be a good
5377 reason in some cases).
5380 More information on known user-agent strings can be found at
5381 <ulink url="http://www.user-agents.org/">http://www.user-agents.org/</ulink>
5383 <ulink url="https://en.wikipedia.org/wiki/User_agent">http://en.wikipedia.org/wiki/User_agent</ulink>.
5389 <term>Example usage:</term>
5391 <screen>+hide-user-agent{Mozilla/5.0 (X11; ElectroBSD i386; rv:78.0) Gecko/20100101 Firefox/78.0}</screen>
5398 <!-- ~~~~~ New section ~~~~~ -->
5399 <sect3 renderas="sect4" id="https-inspection">
5400 <title>https-inspection</title>
5404 <term>Typical use:</term>
5406 <para>Filter encrypted requests and responses</para>
5411 <term>Effect:</term>
5414 Encrypted requests are decrypted, filtered and forwarded encrypted.
5421 <!-- boolean, parameterized, Multi-value -->
5423 <para>Boolean.</para>
5428 <term>Parameter:</term>
5440 This action allows &my-app; to filter encrypted requests and responses.
5441 For this to work &my-app; has to generate a certificate for the web site
5442 and send it to the client which has to accept it.
5445 Before this works the directives in the
5446 <literal><ulink url="config.html#HTTPS-INSPECTION-DIRECTIVES">HTTPS inspection section</ulink></literal>
5447 of the config file have to be configured.
5450 Note that the action has to be enabled based on the CONNECT
5451 request which doesn't contain a path. Enabling it based on
5452 a pattern with path doesn't work as the path is only seen
5453 by &my-app; if the action is already enabled.
5459 <term>Example usage (section):</term>
5461 <screen>{+https-inspection}
5462 www.example.com</screen>
5470 <!-- ~~~~~ New section ~~~~~ -->
5471 <sect3 renderas="sect4" id="ignore-certificate-errors">
5472 <title>ignore-certificate-errors</title>
5476 <term>Typical use:</term>
5478 <para>Filter encrypted requests and responses without verifying the certificate</para>
5483 <term>Effect:</term>
5486 Encrypted requests are forwarded to sites without verifying the certificate.
5493 <!-- Boolean, Parameterized, Multi-value -->
5495 <para>Boolean.</para>
5500 <term>Parameter:</term>
5513 <link linkend="HTTPS-INSPECTION"><quote>+https-inspection</quote></link>
5514 action is used &my-app; by default verifies that the remote site uses a valid
5518 If the certificate can't be validated by &my-app; the connection is aborted.
5521 This action disables the certificate check so requests to sites
5522 with certificates that can't be validated are allowed.
5525 Note that enabling this action allows Man-in-the-middle attacks.
5531 <term>Example usage:</term>
5534 {+ignore-certificate-errors}
5543 <!-- ~~~~~ New section ~~~~~ -->
5544 <sect3 renderas="sect4" id="limit-connect">
5545 <title>limit-connect</title>
5549 <term>Typical use:</term>
5551 <para>Prevent abuse of <application>Privoxy</application> as a TCP proxy relay or disable SSL for untrusted sites</para>
5556 <term>Effect:</term>
5559 Specifies to which ports HTTP CONNECT requests are allowable.
5566 <!-- Boolean, Parameterized, Multi-value -->
5568 <para>Parameterized.</para>
5573 <term>Parameter:</term>
5576 A comma-separated list of ports or port ranges (the latter using dashes, with the minimum
5577 defaulting to 0 and the maximum to 65K).
5586 By default, i.e. if no <literal>limit-connect</literal> action applies,
5587 <application>Privoxy</application> allows HTTP CONNECT requests to all
5588 ports. Use <literal>limit-connect</literal> if fine-grained control
5589 is desired for some or all destinations.
5592 The CONNECT methods exists in HTTP to allow access to secure websites
5593 (<quote>https://</quote> URLs) through proxies. It works very simply:
5594 the proxy connects to the server on the specified port, and then
5595 short-circuits its connections to the client and to the remote server.
5596 This means CONNECT-enabled proxies can be used as TCP relays very easily.
5599 <application>Privoxy</application> relays HTTPS traffic without seeing
5600 the decoded content. Websites can leverage this limitation to circumvent &my-app;'s
5601 filters. By specifying an invalid port range you can disable HTTPS entirely.
5607 <term>Example usages:</term>
5609 <!-- I had trouble getting the spacing to look right in my browser -->
5610 <!-- I probably have the wrong font setup, bollocks. -->
5611 <!-- Apparently the emphasis tag uses a proportional font no matter what -->
5612 <screen>+limit-connect{443} # Port 443 is OK.
5613 +limit-connect{80,443} # Ports 80 and 443 are OK.
5614 +limit-connect{-3, 7, 20-100, 500-} # Ports less than 3, 7, 20 to 100 and above 500 are OK.
5615 +limit-connect{-} # All ports are OK
5616 +limit-connect{,} # No HTTPS/SSL traffic is allowed</screen>
5623 <!-- ~~~~~ New section ~~~~~ -->
5624 <sect3 renderas="sect4" id="limit-cookie-lifetime">
5625 <title>limit-cookie-lifetime</title>
5629 <term>Typical use:</term>
5631 <para>Limit the lifetime of HTTP cookies to a couple of minutes or hours.</para>
5636 <term>Effect:</term>
5639 Overwrites the expires field in Set-Cookie server headers if it's above the specified limit.
5646 <!-- Boolean, Parameterized, Multi-value -->
5648 <para>Parameterized.</para>
5653 <term>Parameter:</term>
5656 The lifetime limit in minutes, or 0.
5665 This action reduces the lifetime of HTTP cookies coming from the
5666 server to the specified number of minutes, starting from the time
5667 the cookie passes Privoxy.
5670 Cookies with a lifetime below the limit are not modified.
5671 The lifetime of session cookies is set to the specified limit.
5674 The effect of this action depends on the server.
5677 In case of servers which refresh their cookies with each response
5678 (or at least frequently), the lifetime limit set by this action
5680 Thus, a session associated with the cookie continues to work with
5681 this action enabled, as long as a new request is made before the
5682 last limit set is reached.
5685 However, some servers send their cookies once, with a lifetime of several
5686 years (the year 2037 is a popular choice), and do not refresh them
5687 until a certain event in the future, for example the user logging out.
5688 In this case this action may limit the absolute lifetime of the session,
5689 even if requests are made frequently.
5692 If the parameter is <quote>0</quote>, this action behaves like
5693 <literal><link linkend="session-cookies-only">session-cookies-only</link></literal>.
5699 <term>Example usages:</term>
5701 <screen>+limit-cookie-lifetime{60}</screen>
5707 <!-- ~~~~~ New section ~~~~~ -->
5708 <sect3 renderas="sect4" id="prevent-compression">
5709 <title>prevent-compression</title>
5713 <term>Typical use:</term>
5716 Ensure that servers send the content uncompressed, so it can be
5717 passed through <literal><link linkend="filter">filter</link></literal>s.
5723 <term>Effect:</term>
5726 Removes the Accept-Encoding header which can be used to ask for compressed transfer.
5733 <!-- Boolean, Parameterized, Multi-value -->
5735 <para>Boolean.</para>
5740 <term>Parameter:</term>
5752 More and more websites send their content compressed by default, which
5753 is generally a good idea and saves bandwidth. But the <literal><link
5754 linkend="filter">filter</link></literal> and
5755 <literal><link linkend="deanimate-gifs">deanimate-gifs</link></literal>
5756 actions need access to the uncompressed data.
5759 When compiled with zlib support (available since &my-app; 3.0.7), content that should be
5760 filtered is decompressed on-the-fly and you don't have to worry about this action.
5761 If you are using an older &my-app; version, or one that hasn't been compiled with zlib
5762 support, this action can be used to convince the server to send the content uncompressed.
5765 Most text-based instances compress very well, the size is seldom decreased by less than 50%,
5766 for markup-heavy instances like news feeds saving more than 90% of the original size isn't
5770 Not using compression will therefore slow down the transfer, and you should only
5771 enable this action if you really need it. As of &my-app; 3.0.7 it's disabled in all
5772 predefined action settings.
5775 Note that some (rare) ill-configured sites don't handle requests for uncompressed
5776 documents correctly. Broken PHP applications tend to send an empty document body,
5777 some IIS versions only send the beginning of the content and some content delivery
5778 networks let the connection time out.
5779 If you enable <literal>prevent-compression</literal> per default, you might
5780 want to add exceptions for those sites. See the example for how to do that.
5786 <term>Example usage (sections):</term>
5789 # Selectively turn off compression, and enable a filter
5791 { +filter{tiny-textforms} +prevent-compression }
5792 # Match only these sites
5797 # Or instead, we could set a universal default:
5799 { +prevent-compression }
5802 # Then maybe make exceptions for broken sites:
5804 { -prevent-compression }
5814 <!-- ~~~~~ New section ~~~~~ -->
5815 <sect3 renderas="sect4" id="overwrite-last-modified">
5816 <title>overwrite-last-modified</title>
5822 <term>Typical use:</term>
5824 <para>Prevent yet another way to track the user's steps between sessions.</para>
5829 <term>Effect:</term>
5832 Deletes the <quote>Last-Modified:</quote> HTTP server header or modifies its value.
5839 <!-- Boolean, Parameterized, Multi-value -->
5841 <para>Parameterized.</para>
5846 <term>Parameter:</term>
5849 One of the keywords: <quote>block</quote>, <quote>reset-to-request-time</quote>
5850 and <quote>randomize</quote>
5859 Removing the <quote>Last-Modified:</quote> header is useful for filter
5860 testing, where you want to force a real reload instead of getting status
5861 code <quote>304</quote>, which would cause the browser to reuse the old
5862 version of the page.
5865 The <quote>randomize</quote> option overwrites the value of the
5866 <quote>Last-Modified:</quote> header with a randomly chosen time
5867 between the original value and the current time. In theory the server
5868 could send each document with a different <quote>Last-Modified:</quote>
5869 header to track visits without using cookies. <quote>Randomize</quote>
5870 makes it impossible and the browser can still revalidate cached documents.
5873 <quote>reset-to-request-time</quote> overwrites the value of the
5874 <quote>Last-Modified:</quote> header with the current time. You could use
5875 this option together with
5876 <literal><link linkend="hide-if-modified-since">hide-if-modified-since</link></literal>
5877 to further customize your random range.
5880 The preferred parameter here is <quote>randomize</quote>. It is safe
5881 to use, as long as the time settings are more or less correct.
5882 If the server sets the <quote>Last-Modified:</quote> header to the time
5883 of the request, the random range becomes zero and the value stays the same.
5884 Therefore you should later randomize it a second time with
5885 <literal><link linkend="hide-if-modified-since">hided-if-modified-since</link></literal>,
5889 It is also recommended to use this action together with
5890 <literal><link linkend="crunch-if-none-match">crunch-if-none-match</link></literal>.
5896 <term>Example usage:</term>
5899 # Let the browser revalidate without being tracked across sessions
5900 { +hide-if-modified-since{-60} \
5901 +overwrite-last-modified{randomize} \
5902 +crunch-if-none-match \
5912 <!-- ~~~~~ New section ~~~~~ -->
5913 <sect3 renderas="sect4" id="redirect">
5914 <title>redirect</title>
5920 <term>Typical use:</term>
5923 Redirect requests to other sites.
5929 <term>Effect:</term>
5932 Convinces the browser that the requested document has been moved
5933 to another location and the browser should get it from there.
5940 <!-- Boolean, Parameterized, Multi-value -->
5942 <para>Parameterized</para>
5947 <term>Parameter:</term>
5950 An absolute URL or a single pcrs command.
5959 Requests to which this action applies are answered with a
5960 HTTP redirect to URLs of your choosing. The new URL is
5961 either provided as parameter, or derived by applying a
5962 single pcrs command to the original URL.
5965 The syntax for pcrs commands is documented in the
5966 <link linkend="filter-file">filter file</link> section.
5969 Requests can't be blocked and redirected at the same time,
5970 applying this action together with
5971 <literal><link linkend="block">block</link></literal>
5972 is a configuration error. Currently the request is blocked
5973 and an error message logged, the behavior may change in the
5974 future and result in Privoxy rejecting the action file.
5977 This action can be combined with
5978 <literal><link linkend="fast-redirects">fast-redirects{check-decoded-url}</link></literal>
5979 to redirect to a decoded version of a rewritten URL.
5982 Use this action carefully, make sure not to create redirection loops
5983 and be aware that using your own redirects might make it
5984 possible to fingerprint your requests.
5987 In case of problems with your redirects, or simply to watch
5988 them working, enable <link linkend="DEBUG">debug 128</link>.
5994 <term>Example usages:</term>
5997 # Replace example.com's style sheet with another one
5998 { +redirect{http://localhost/css-replacements/example.com.css} }
5999 example.com/stylesheet\.css
6001 # Create a short, easy to remember nickname for a favorite site
6002 # (relies on the browser to accept and forward invalid URLs to &my-app;)
6003 { +redirect{https://www.privoxy.org/user-manual/actions-file.html} }
6006 # Always use the expanded view for Undeadly.org articles
6007 # (Note the $ at the end of the URL pattern to make sure
6008 # the request for the rewritten URL isn't redirected as well)
6009 {+redirect{s@$@&mode=expanded@}}
6010 undeadly.org/cgi\?action=article&sid=\d*$
6012 # Redirect Google search requests to MSN
6013 {+redirect{s@^http://[^/]*/search\?q=([^&]*).*@http://search.msn.com/results.aspx?q=$1@}}
6016 # Redirect MSN search requests to Yahoo
6017 {+redirect{s@^http://[^/]*/results\.aspx\?q=([^&]*).*@http://search.yahoo.com/search?p=$1@}}
6018 search.msn.com//results\.aspx\?q=
6020 # Redirect http://example.com/&bla=fasel&toChange=foo (and any other value but "bar")
6021 # to http://example.com/&bla=fasel&toChange=bar
6023 # The URL pattern makes sure that the following request isn't redirected again.
6024 {+redirect{s@toChange=[^&]+@toChange=bar@}}
6025 example.com/.*toChange=(?!bar)
6027 # Add a shortcut to look up illumos bugs
6028 {+redirect{s@^http://i([0-9]+)/.*@https://www.illumos.org/issues/$1@}}
6029 # Redirected URL = http://i4974/
6030 # Redirect Destination = https://www.illumos.org/issues/4974
6031 i[0-9][0-9][0-9][0-9]*/
6033 # Redirect requests for the old Tor Hidden Service of the Privoxy website to the new one
6034 {+redirect{s@^http://jvauzb4sb3bwlsnc.onion/@http://l3tczdiiwoo63iwxty4lhs6p7eaxop5micbn7vbliydgv63x5zrrrfyd.onion/@}}
6035 jvauzb4sb3bwlsnc.onion/
6037 # Redirect remote requests for this manual
6038 # to the local version delivered by Privoxy
6039 {+redirect{s@^http://www@http://config@}}
6040 www.privoxy.org/user-manual/</screen>
6048 <!-- ~~~~~ New section ~~~~~ -->
6049 <sect3 renderas="sect4" id="server-header-filter">
6050 <title>server-header-filter</title>
6054 <term>Typical use:</term>
6057 Rewrite or remove single server headers.
6063 <term>Effect:</term>
6066 All server headers to which this action applies are filtered on-the-fly
6067 through the specified regular expression based substitutions.
6074 <!-- boolean, parameterized, Multi-value -->
6076 <para>Multi-value.</para>
6081 <term>Parameter:</term>
6084 The name of a server-header filter, as defined in one of the
6085 <link linkend="filter-file">filter files</link>.
6094 Server-header filters are applied to each header on its own, not to
6095 all at once. This makes it easier to diagnose problems, but on the downside
6096 you can't write filters that only change header x if header y's value is z.
6097 You can do that by using tags though.
6100 Server-header filters are executed after the other header actions have finished
6101 and use their output as input.
6104 Please refer to the <link linkend="filter-file">filter file chapter</link>
6105 to learn which server-header filters are available by default, and how to
6112 <term>Example usage (section):</term>
6115 {+server-header-filter{html-to-xml}}
6116 example.org/xml-instance-that-is-delivered-as-html
6118 {+server-header-filter{xml-to-html}}
6119 example.org/instance-that-is-delivered-as-xml-but-is-not
6128 <!-- ~~~~~ New section ~~~~~ -->
6129 <sect3 renderas="sect4" id="server-header-tagger">
6130 <title>server-header-tagger</title>
6134 <term>Typical use:</term>
6137 Enable or disable filters based on the Content-Type header.
6143 <term>Effect:</term>
6146 Server headers to which this action applies are filtered on-the-fly through
6147 the specified regular expression based substitutions, the result is used as
6155 <!-- boolean, parameterized, Multi-value -->
6157 <para>Multi-value.</para>
6162 <term>Parameter:</term>
6165 The name of a server-header tagger, as defined in one of the
6166 <link linkend="filter-file">filter files</link>.
6175 Server-header taggers are applied to each header on its own,
6176 and as the header isn't modified, each tagger <quote>sees</quote>
6180 Server-header taggers are executed before all other header actions
6181 that modify server headers. Their tags can be used to control
6182 all of the other server-header actions, the content filters
6183 and the crunch actions (<link linkend="redirect">redirect</link>
6184 and <link linkend="block">block</link>).
6187 Obviously crunching based on tags created by server-header taggers
6188 doesn't prevent the request from showing up in the server's log file.
6195 <term>Example usage (section):</term>
6198 # Tag every request with the content type declared by the server
6199 {+server-header-tagger{content-type}}
6202 # If the response has a tag starting with 'image/' enable an external
6203 # filter that only applies to images.
6205 # Note that the filter is not available by default, it's just a
6206 # <literal><link linkend="external-filter-syntax">silly example</link></literal>.
6207 {+external-filter{rotate-image} +force-text-mode}
6217 <!-- ~~~~~ New section ~~~~~ -->
6218 <sect3 renderas="sect4" id="suppress-tag">
6219 <title>suppress-tag</title>
6223 <term>Typical use:</term>
6226 Suppress client or server tag.
6232 <term>Effect:</term>
6235 Server or client tags to which this action applies are not added to the request,
6236 thus making all actions that are specific to these request tags inactive.
6243 <!-- boolean, parameterized, Multi-value -->
6245 <para>Multi-value.</para>
6250 <term>Parameter:</term>
6253 The result tag of a server-header or client-header tagger, as defined in one of the
6254 <link linkend="filter-file">filter files</link>.
6260 <term>Example usage (section):</term>
6263 # Suppress tag produced by range-requests client-header tagger for requests coming from address 10.0.0.1
6264 {+suppress-tag{RANGE-REQUEST}}
6265 TAG:^IP-ADDRESS: 10\.0\.0\.1$
6274 <!-- ~~~~~ New section ~~~~~ -->
6275 <sect3 renderas="sect4" id="session-cookies-only">
6276 <title>session-cookies-only</title>
6280 <term>Typical use:</term>
6283 Allow only temporary <quote>session</quote> cookies (for the current
6284 browser session <emphasis>only</emphasis>).
6290 <term>Effect:</term>
6293 Deletes the <quote>expires</quote> field from <quote>Set-Cookie:</quote>
6294 server headers. Most browsers will not store such cookies permanently and
6295 forget them in between sessions.
6302 <!-- Boolean, Parameterized, Multi-value -->
6304 <para>Boolean.</para>
6309 <term>Parameter:</term>
6321 This is less strict than <literal><link linkend="crunch-incoming-cookies">crunch-incoming-cookies</link></literal> /
6322 <literal><link linkend="crunch-outgoing-cookies">crunch-outgoing-cookies</link></literal> and allows you to browse
6323 websites that insist or rely on setting cookies, without compromising your privacy too badly.
6326 Most browsers will not permanently store cookies that have been processed by
6327 <literal>session-cookies-only</literal> and will forget about them between sessions.
6328 This makes profiling cookies useless, but won't break sites which require cookies so
6329 that you can log in for transactions. This is generally turned on for all
6330 sites, and is the recommended setting.
6333 It makes <emphasis>no sense at all</emphasis> to use <literal>session-cookies-only</literal>
6334 together with <literal><link linkend="crunch-incoming-cookies">crunch-incoming-cookies</link></literal> or
6335 <literal><link linkend="crunch-outgoing-cookies">crunch-outgoing-cookies</link></literal>. If you do, cookies
6336 will be plainly killed.
6339 Note that it is up to the browser how it handles such cookies without an <quote>expires</quote>
6340 field. If you use an exotic browser, you might want to try it out to be sure.
6343 This setting also has no effect on cookies that may have been stored
6344 previously by the browser before starting <application>Privoxy</application>.
6345 These would have to be removed manually.
6348 <application>Privoxy</application> also uses
6349 the <link linkend="filter-content-cookies">content-cookies filter</link>
6350 to block some types of cookies. Content cookies are not effected by
6351 <literal>session-cookies-only</literal>.
6357 <term>Example usage:</term>
6359 <screen>+session-cookies-only</screen>
6366 <!-- ~~~~~ New section ~~~~~ -->
6367 <sect3 renderas="sect4" id="set-image-blocker">
6368 <title>set-image-blocker</title>
6372 <term>Typical use:</term>
6374 <para>Choose the replacement for blocked images</para>
6379 <term>Effect:</term>
6382 This action alone doesn't do anything noticeable. If <emphasis>both</emphasis>
6383 <literal><link linkend="block">block</link></literal> <emphasis>and</emphasis> <literal><link
6384 linkend="handle-as-image">handle-as-image</link></literal> <emphasis>also</emphasis>
6385 apply, i.e. if the request is to be blocked as an image,
6386 <emphasis>then</emphasis> the parameter of this action decides what will be
6387 sent as a replacement.
6394 <!-- Boolean, Parameterized, Multi-value -->
6396 <para>Parameterized.</para>
6401 <term>Parameter:</term>
6406 <quote>pattern</quote> to send a built-in checkerboard pattern image. The image is visually
6407 decent, scales very well, and makes it obvious where banners were busted.
6412 <quote>blank</quote> to send a built-in transparent image. This makes banners disappear
6413 completely, but makes it hard to detect where <application>Privoxy</application> has blocked
6414 images on a given page and complicates troubleshooting if <application>Privoxy</application>
6415 has blocked innocent images, like navigation icons.
6420 <quote><replaceable class="parameter">target-url</replaceable></quote> to
6421 send a redirect to <replaceable class="parameter">target-url</replaceable>. You can redirect
6422 to any image anywhere, even in your local filesystem via <quote>file:///</quote> URL.
6423 (But note that not all browsers support redirecting to a local file system).
6426 A good application of redirects is to use special <application>Privoxy</application>-built-in
6427 URLs, which send the built-in images, as <replaceable class="parameter">target-url</replaceable>.
6428 This has the same visual effect as specifying <quote>blank</quote> or <quote>pattern</quote> in
6429 the first place, but enables your browser to cache the replacement image, instead of requesting
6430 it over and over again.
6441 The URLs for the built-in images are <quote>http://config.privoxy.org/send-banner?type=<replaceable
6442 class="parameter">type</replaceable></quote>, where <replaceable class="parameter">type</replaceable> is
6443 either <quote>blank</quote> or <quote>pattern</quote>.
6446 There is a third (advanced) type, called <quote>auto</quote>. It is <emphasis>NOT</emphasis> to be
6447 used in <literal>set-image-blocker</literal>, but meant for use from <link linkend="filter-file">filters</link>.
6448 Auto will select the type of image that would have applied to the referring page, had it been an image.
6454 <term>Example usage:</term>
6459 <screen>+set-image-blocker{pattern}</screen>
6461 Redirect to the BSD daemon:
6463 <screen>+set-image-blocker{http://www.freebsd.org/gifs/dae_up3.gif}</screen>
6465 Redirect to the built-in pattern for better caching:
6467 <screen>+set-image-blocker{http://config.privoxy.org/send-banner?type=pattern}</screen>
6474 <!-- ~~~~~ New section ~~~~~ -->
6475 <sect3 id="summary">
6476 <title>Summary</title>
6478 Note that many of these actions have the potential to cause a page to
6479 misbehave, possibly even not to display at all. There are many ways
6480 a site designer may choose to design his site, and what HTTP header
6481 content, and other criteria, he may depend on. There is no way to have hard
6482 and fast rules for all sites. See the <link
6483 linkend="ACTIONSANAT">Appendix</link> for a brief example on troubleshooting
6489 <!-- ~~~~~ New section ~~~~~ -->
6490 <sect2 id="aliases">
6491 <title>Aliases</title>
6493 Custom <quote>actions</quote>, known to <application>Privoxy</application>
6494 as <quote>aliases</quote>, can be defined by combining other actions.
6495 These can in turn be invoked just like the built-in actions.
6496 Currently, an alias name can contain any character except space, tab,
6498 <quote>{</quote> and <quote>}</quote>, but we <emphasis>strongly
6499 recommend</emphasis> that you only use <quote>a</quote> to <quote>z</quote>,
6500 <quote>0</quote> to <quote>9</quote>, <quote>+</quote>, and <quote>-</quote>.
6501 Alias names are not case sensitive, and are not required to start with a
6502 <quote>+</quote> or <quote>-</quote> sign, since they are merely textually
6506 Aliases can be used throughout the actions file, but they <emphasis>must be
6507 defined in a special section at the top of the file!</emphasis>
6508 And there can only be one such section per actions file. Each actions file may
6509 have its own alias section, and the aliases defined in it are only visible
6513 There are two main reasons to use aliases: One is to save typing for frequently
6514 used combinations of actions, the other one is a gain in flexibility: If you
6515 decide once how you want to handle shops by defining an alias called
6516 <quote>shop</quote>, you can later change your policy on shops in
6517 <emphasis>one</emphasis> place, and your changes will take effect everywhere
6518 in the actions file where the <quote>shop</quote> alias is used. Calling aliases
6519 by their purpose also makes your actions files more readable.
6522 Currently, there is one big drawback to using aliases, though:
6523 <application>Privoxy</application>'s built-in web-based action file
6524 editor honors aliases when reading the actions files, but it expands
6525 them before writing. So the effects of your aliases are of course preserved,
6526 but the aliases themselves are lost when you edit sections that use aliases
6531 Now let's define some aliases...
6535 # Useful custom aliases we can use later.
6537 # Note the (required!) section header line and that this section
6538 # must be at the top of the actions file!
6542 # These aliases just save typing later:
6543 # (Note that some already use other aliases!)
6545 +crunch-all-cookies = +<link linkend="CRUNCH-INCOMING-COOKIES">crunch-incoming-cookies</link> +<link linkend="CRUNCH-OUTGOING-COOKIES">crunch-outgoing-cookies</link>
6546 -crunch-all-cookies = -<link linkend="CRUNCH-INCOMING-COOKIES">crunch-incoming-cookies</link> -<link linkend="CRUNCH-OUTGOING-COOKIES">crunch-outgoing-cookies</link>
6547 +block-as-image = +block{Blocked image.} +handle-as-image
6548 allow-all-cookies = -crunch-all-cookies -<link linkend="SESSION-COOKIES-ONLY">session-cookies-only</link> -<link linkend="FILTER-CONTENT-COOKIES">filter{content-cookies}</link>
6550 # These aliases define combinations of actions
6551 # that are useful for certain types of sites:
6553 fragile = -<link linkend="BLOCK">block</link> -<link linkend="FILTER">filter</link> -crunch-all-cookies -<link linkend="FAST-REDIRECTS">fast-redirects</link> -<link linkend="HIDE-REFERER">hide-referrer</link> -<link linkend="PREVENT-COMPRESSION">prevent-compression</link>
6555 shop = -crunch-all-cookies -<link linkend="FILTER-ALL-POPUPS">filter{all-popups}</link>
6557 # Short names for other aliases, for really lazy people ;-)
6559 c0 = +crunch-all-cookies
6560 c1 = -crunch-all-cookies
6564 ...and put them to use. These sections would appear in the lower part of an
6565 actions file and define exceptions to the default actions (as specified further
6566 up for the <quote>/</quote> pattern):
6570 # These sites are either very complex or very keen on
6571 # user data and require minimal interference to work:
6574 .office.microsoft.com
6575 .windowsupdate.microsoft.com
6576 # Gmail is really mail.google.com, not gmail.com
6580 # Allow cookies (for setting and retrieving your customer data)
6584 .worldpay.com # for quietpc.com
6587 # These shops require pop-ups:
6589 {-filter{all-popups} -filter{unsolicited-popups}}
6595 Aliases like <quote>shop</quote> and <quote>fragile</quote> are typically used for
6596 <quote>problem</quote> sites that require more than one action to be disabled
6597 in order to function properly.
6603 <!-- ~~~~~ New section ~~~~~ -->
6604 <sect2 id="act-examples">
6605 <title>Actions Files Tutorial</title>
6607 The above chapters have shown <link linkend="actions-file">which actions files
6608 there are and how they are organized</link>, how actions are <link
6609 linkend="actions">specified</link> and <link linkend="actions-apply">applied
6610 to URLs</link>, how <link linkend="af-patterns">patterns</link> work, and how to
6611 define and use <link linkend="aliases">aliases</link>. Now, let's look at an
6612 example <filename>match-all.action</filename>, <filename>default.action</filename>
6613 and <filename>user.action</filename> file and see how all these pieces come together:
6616 <sect3 id="match-all">
6617 <title>match-all.action</title>
6619 Remember <emphasis>all actions are disabled when matching starts</emphasis>,
6620 so we have to explicitly enable the ones we want.
6624 While the <filename>match-all.action</filename> file only contains a
6625 single section, it is probably the most important one. It has only one
6626 pattern, <quote><literal>/</literal></quote>, but this pattern
6627 <link linkend="af-patterns">matches all URLs</link>. Therefore, the set of
6628 actions used in this <quote>default</quote> section <emphasis>will
6629 be applied to all requests as a start</emphasis>. It can be partly or
6630 wholly overridden by other actions files like <filename>default.action</filename>
6631 and <filename>user.action</filename>, but it will still be largely responsible
6632 for your overall browsing experience.
6636 Again, at the start of matching, all actions are disabled, so there is
6637 no need to disable any actions here. (Remember: a <quote>+</quote>
6638 preceding the action name enables the action, a <quote>-</quote> disables!).
6639 Also note how this long line has been made more readable by splitting it into
6640 multiple lines with line continuation.
6645 +<link linkend="CHANGE-X-FORWARDED-FOR">change-x-forwarded-for{block}</link> \
6646 +<link linkend="HIDE-FROM-HEADER">hide-from-header{block}</link> \
6647 +<link linkend="SET-IMAGE-BLOCKER">set-image-blocker{pattern}</link> \
6653 The default behavior is now set.
6657 <sect3 id="default-action">
6658 <title>default.action</title>
6661 If you aren't a developer, there's no need for you to edit the
6662 <filename>default.action</filename> file. It is maintained by
6663 the &my-app; developers and if you disagree with some of the
6664 sections, you should overrule them in your <filename>user.action</filename>.
6668 Understanding the <filename>default.action</filename> file can
6669 help you with your <filename>user.action</filename>, though.
6673 The first section in this file is a special section for internal use
6674 that prevents older &my-app; versions from reading the file:
6678 ##########################################################################
6679 # Settings -- Don't change! For internal Privoxy use ONLY.
6680 ##########################################################################
6682 for-privoxy-version=3.0.11</screen>
6685 After that comes the (optional) alias section. We'll use the example
6686 section from the above <link linkend="aliases">chapter on aliases</link>,
6687 that also explains why and how aliases are used:
6691 ##########################################################################
6693 ##########################################################################
6696 # These aliases just save typing later:
6697 # (Note that some already use other aliases!)
6699 +crunch-all-cookies = +<link linkend="CRUNCH-INCOMING-COOKIES">crunch-incoming-cookies</link> +<link linkend="CRUNCH-OUTGOING-COOKIES">crunch-outgoing-cookies</link>
6700 -crunch-all-cookies = -<link linkend="CRUNCH-INCOMING-COOKIES">crunch-incoming-cookies</link> -<link linkend="CRUNCH-OUTGOING-COOKIES">crunch-outgoing-cookies</link>
6701 +block-as-image = +block{Blocked image.} +handle-as-image
6702 mercy-for-cookies = -crunch-all-cookies -<link linkend="SESSION-COOKIES-ONLY">session-cookies-only</link> -<link linkend="FILTER-CONTENT-COOKIES">filter{content-cookies}</link>
6704 # These aliases define combinations of actions
6705 # that are useful for certain types of sites:
6707 fragile = -<link linkend="BLOCK">block</link> -<link linkend="FILTER">filter</link> -crunch-all-cookies -<link linkend="FAST-REDIRECTS">fast-redirects</link> -<link linkend="HIDE-REFERER">hide-referrer</link>
6708 shop = -crunch-all-cookies -<link linkend="FILTER-ALL-POPUPS">filter{all-popups}</link></screen>
6711 The first of our specialized sections is concerned with <quote>fragile</quote>
6712 sites, i.e. sites that require minimum interference, because they are either
6713 very complex or very keen on tracking you (and have mechanisms in place that
6714 make them unusable for people who avoid being tracked). We will use
6715 our pre-defined <literal>fragile</literal> alias instead of stating the list
6716 of actions explicitly:
6720 ##########################################################################
6721 # Exceptions for sites that'll break under the default action set:
6722 ##########################################################################
6724 # "Fragile" Use a minimum set of actions for these sites (see alias above):
6727 .office.microsoft.com # surprise, surprise!
6728 .windowsupdate.microsoft.com
6729 mail.google.com</screen>
6732 Shopping sites are not as fragile, but they typically
6733 require cookies to log in, and pop-up windows for shopping
6734 carts or item details. Again, we'll use a pre-defined alias:
6742 .worldpay.com # for quietpc.com
6744 .scan.co.uk</screen>
6747 The <literal><link linkend="FAST-REDIRECTS">fast-redirects</link></literal>
6748 action, which may have been enabled in <filename>match-all.action</filename>,
6749 breaks some sites. So disable it for popular sites where we know it misbehaves:
6753 { -<link linkend="FAST-REDIRECTS">fast-redirects</link> }
6757 .altavista.com/.*(like|url|link):http
6758 .altavista.com/trans.*urltext=http
6759 .nytimes.com</screen>
6762 It is important that <application>Privoxy</application> knows which
6763 URLs belong to images, so that <emphasis>if</emphasis> they are to
6764 be blocked, a substitute image can be sent, rather than an HTML page.
6765 Contacting the remote site to find out is not an option, since it
6766 would destroy the loading time advantage of banner blocking, and it
6767 would feed the advertisers information about you. We can mark any
6768 URL as an image with the <literal><link
6769 linkend="handle-as-image">handle-as-image</link></literal> action,
6770 and marking all URLs that end in a known image file extension is a
6775 ##########################################################################
6777 ##########################################################################
6779 # Define which file types will be treated as images, in case they get
6780 # blocked further down this file:
6782 { +<link linkend="HANDLE-AS-IMAGE">handle-as-image</link> }
6783 /.*\.(gif|jpe?g|png|bmp|ico)$</screen>
6786 And then there are known banner sources. They often use scripts to
6787 generate the banners, so it won't be visible from the URL that the
6788 request is for an image. Hence we block them <emphasis>and</emphasis>
6789 mark them as images in one go, with the help of our
6790 <literal>+block-as-image</literal> alias defined above. (We could of
6791 course just as well use <literal>+<link linkend="block">block</link>
6792 +<link linkend="handle-as-image">handle-as-image</link></literal> here.)
6793 Remember that the type of the replacement image is chosen by the
6794 <literal><link linkend="set-image-blocker">set-image-blocker</link></literal>
6795 action. Since all URLs have matched the default section with its
6796 <literal>+<link linkend="set-image-blocker">set-image-blocker</link>{pattern}</literal>
6797 action before, it still applies and needn't be repeated:
6801 # Known ad generators:
6806 .ad.*.doubleclick.net
6807 .a.yimg.com/(?:(?!/i/).)*$
6808 .a[0-9].yimg.com/(?:(?!/i/).)*$
6813 One of the most important jobs of <application>Privoxy</application>
6814 is to block banners. Many of these can be <quote>blocked</quote>
6815 by the <literal><link linkend="filter">filter</link>{banners-by-size}</literal>
6816 action, which we enabled above, and which deletes the references to banner
6817 images from the pages while they are loaded, so the browser doesn't request
6818 them anymore, and hence they don't need to be blocked here. But this naturally
6819 doesn't catch all banners, and some people choose not to use filters, so we
6820 need a comprehensive list of patterns for banner URLs here, and apply the
6821 <literal><link linkend="block">block</link></literal> action to them.
6824 First comes many generic patterns, which do most of the work, by
6825 matching typical domain and path name components of banners. Then comes
6826 a list of individual patterns for specific sites, which is omitted here
6827 to keep the example short:
6831 ##########################################################################
6832 # Block these fine banners:
6833 ##########################################################################
6834 { <link linkend="BLOCK">+block{Banner ads.}</link> }
6842 /.*count(er)?\.(pl|cgi|exe|dll|asp|php[34]?)
6843 /(?:.*/)?(publicite|werbung|rekla(ma|me|am)|annonse|maino(kset|nta|s)?)/
6845 # Site-specific patterns (abbreviated):
6847 .hitbox.com</screen>
6850 It's quite remarkable how many advertisers actually call their banner
6851 servers ads.<replaceable>company</replaceable>.com, or call the directory
6852 in which the banners are stored literally <quote>banners</quote>. So the above
6853 generic patterns are surprisingly effective.
6856 But being very generic, they necessarily also catch URLs that we don't want
6857 to block. The pattern <literal>.*ads.</literal> e.g. catches
6858 <quote>nasty-<emphasis>ads</emphasis>.nasty-corp.com</quote> as intended,
6859 but also <quote>downlo<emphasis>ads</emphasis>.sourcefroge.net</quote> or
6860 <quote><emphasis>ads</emphasis>l.some-provider.net.</quote> So here come some
6861 well-known exceptions to the <literal>+<link linkend="BLOCK">block</link></literal>
6865 Note that these are exceptions to exceptions from the default! Consider the URL
6866 <quote>downloads.sourcefroge.net</quote>: Initially, all actions are deactivated,
6867 so it wouldn't get blocked. Then comes the defaults section, which matches the
6868 URL, but just deactivates the <literal><link linkend="BLOCK">block</link></literal>
6869 action once again. Then it matches <literal>.*ads.</literal>, an exception to the
6870 general non-blocking policy, and suddenly
6871 <literal><link linkend="BLOCK">+block</link></literal> applies. And now, it'll match
6872 <literal>.*loads.</literal>, where <literal><link linkend="BLOCK">-block</link></literal>
6873 applies, so (unless it matches <emphasis>again</emphasis> further down) it ends up
6874 with no <literal><link linkend="BLOCK">block</link></literal> action applying.
6878 ##########################################################################
6879 # Save some innocent victims of the above generic block patterns:
6880 ##########################################################################
6884 { -<link linkend="BLOCK">block</link> }
6885 adv[io]*. # (for advogato.org and advice.*)
6886 adsl. # (has nothing to do with ads)
6887 adobe. # (has nothing to do with ads either)
6888 ad[ud]*. # (adult.* and add.*)
6889 .edu # (universities don't host banners (yet!))
6890 .*loads. # (downloads, uploads etc)
6898 www.globalintersec.com/adv # (adv = advanced)
6899 www.ugu.com/sui/ugu/adv</screen>
6902 Filtering source code can have nasty side effects,
6903 so make an exception for our friends at sourceforge.net,
6904 and all paths with <quote>cvs</quote> in them. Note that
6905 <literal>-<link linkend="FILTER">filter</link></literal>
6906 disables <emphasis>all</emphasis> filters in one fell swoop!
6910 # Don't filter code!
6912 { -<link linkend="FILTER">filter</link> }
6917 .sourceforge.net</screen>
6920 The actual <filename>default.action</filename> is of course much more
6921 comprehensive, but we hope this example made clear how it works.
6926 <sect3 id="user-action"><title>user.action</title>
6929 So far we are painting with a broad brush by setting general policies,
6930 which would be a reasonable starting point for many people. Now,
6931 you might want to be more specific and have customized rules that
6932 are more suitable to your personal habits and preferences. These would
6933 be for narrowly defined situations like your ISP or your bank, and should
6934 be placed in <filename>user.action</filename>, which is parsed after all other
6935 actions files and hence has the last word, over-riding any previously
6936 defined actions. <filename>user.action</filename> is also a
6937 <emphasis>safe</emphasis> place for your personal settings, since
6938 <filename>default.action</filename> is actively maintained by the
6939 <application>Privoxy</application> developers and you'll probably want
6940 to install updated versions from time to time.
6944 So let's look at a few examples of things that one might typically do in
6945 <filename>user.action</filename>:
6949 <!-- brief sample user.action here -->
6952 # My user.action file. <fred@example.com></screen>
6955 As <link linkend="aliases">aliases</link> are local to the actions
6956 file that they are defined in, you can't use the ones from
6957 <filename>default.action</filename>, unless you repeat them here:
6961 # Aliases are local to the file they are defined in.
6962 # (Re-)define aliases for this file:
6966 # These aliases just save typing later, and the alias names should
6967 # be self explanatory.
6969 +crunch-all-cookies = +crunch-incoming-cookies +crunch-outgoing-cookies
6970 -crunch-all-cookies = -crunch-incoming-cookies -crunch-outgoing-cookies
6971 allow-all-cookies = -crunch-all-cookies -session-cookies-only
6972 allow-popups = -filter{all-popups}
6973 +block-as-image = +block{Blocked as image.} +handle-as-image
6974 -block-as-image = -block
6976 # These aliases define combinations of actions that are useful for
6977 # certain types of sites:
6979 fragile = -block -crunch-all-cookies -filter -fast-redirects -hide-referrer
6980 shop = -crunch-all-cookies allow-popups
6982 # Allow ads for selected useful free sites:
6984 allow-ads = -block -filter{banners-by-size} -filter{banners-by-link}
6986 # Alias for specific file types that are text, but might have conflicting
6987 # MIME types. We want the browser to force these to be text documents.
6988 handle-as-text = -<link linkend="FILTER">filter</link> +-<link linkend="content-type-overwrite">content-type-overwrite{text/plain}</link> +-<link linkend="FORCE-TEXT-MODE">force-text-mode</link> -<link linkend="HIDE-CONTENT-DISPOSITION">hide-content-disposition</link></screen>
6991 Say you have accounts on some sites that you visit regularly, and
6992 you don't want to have to log in manually each time. So you'd like
6993 to allow persistent cookies for these sites. The
6994 <literal>allow-all-cookies</literal> alias defined above does exactly
6995 that, i.e. it disables crunching of cookies in any direction, and the
6996 processing of cookies to make them only temporary.
7000 { allow-all-cookies }
7008 Your bank is allergic to some filter, but you don't know which, so you disable them all:
7012 { -<link linkend="FILTER">filter</link> }
7013 .your-home-banking-site.com
7017 Some file types you may not want to filter for various reasons:
7021 # Technical documentation is likely to contain strings that might
7022 # erroneously get altered by the JavaScript-oriented filters:
7027 # And this stupid host sends streaming video with a wrong MIME type,
7028 # so that Privoxy thinks it is getting HTML and starts filtering:
7030 stupid-server.example.com/</screen>
7033 Example of a simple <link linkend="BLOCK">block</link> action. Say you've
7034 seen an ad on your favourite page on example.com that you want to get rid of.
7035 You have right-clicked the image, selected <quote>copy image location</quote>
7036 and pasted the URL below while removing the leading http://, into a
7037 <literal>{ +block{} }</literal> section. Note that <literal>{ +handle-as-image
7038 }</literal> need not be specified, since all URLs ending in
7039 <literal>.gif</literal> will be tagged as images by the general rules as set
7040 in default.action anyway:
7044 { +<link linkend="BLOCK">block</link>{Nasty ads.} }
7045 www.example.com/nasty-ads/sponsor\.gif
7046 another.example.net/more/junk/here/
7050 The URLs of dynamically generated banners, especially from large banner
7051 farms, often don't use the well-known image file name extensions, which
7052 makes it impossible for <application>Privoxy</application> to guess
7053 the file type just by looking at the URL.
7054 You can use the <literal>+block-as-image</literal> alias defined above for
7056 Note that objects which match this rule but then turn out NOT to be an
7057 image are typically rendered as a <quote>broken image</quote> icon by the
7058 browser. Use cautiously.
7070 Now you noticed that the default configuration breaks Forbes Magazine,
7071 but you were too lazy to find out which action is the culprit, and you
7072 were again too lazy to give <link linkend="contact">feedback</link>, so
7073 you just used the <literal>fragile</literal> alias on the site, and
7074 -- <emphasis>whoa!</emphasis> -- it worked. The <literal>fragile</literal>
7075 aliases disables those actions that are most likely to break a site. Also,
7076 good for testing purposes to see if it is <application>Privoxy</application>
7077 that is causing the problem or not. We later find other regular sites
7078 that misbehave, and add those to our personalized list of troublemakers:
7089 You like the <quote>fun</quote> text replacements in <filename>default.filter</filename>,
7090 but it is disabled in the distributed actions file.
7091 So you'd like to turn it on in your private,
7092 update-safe config, once and for all:
7096 { +<link linkend="filter-fun">filter{fun}</link> }
7101 Note that the above is not really a good idea: There are exceptions
7102 to the filters in <filename>default.action</filename> for things that
7103 really shouldn't be filtered, like code on CVS->Web interfaces. Since
7104 <filename>user.action</filename> has the last word, these exceptions
7105 won't be valid for the <quote>fun</quote> filtering specified here.
7109 You might also worry about how your favourite free websites are
7110 funded, and find that they rely on displaying banner advertisements
7111 to survive. So you might want to specifically allow banners for those
7112 sites that you feel provide value to you:
7123 Note that <literal>allow-ads</literal> has been aliased to
7124 <literal>-<link linkend="block">block</link></literal>,
7125 <literal>-<link linkend="filter-banners-by-size">filter{banners-by-size}</link></literal>, and
7126 <literal>-<link linkend="filter-banners-by-link">filter{banners-by-link}</link></literal> above.
7130 Invoke another alias here to force an over-ride of the MIME type <literal>
7131 application/x-sh</literal> which typically would open a download type
7132 dialog. In my case, I want to look at the shell script, and then I can save
7133 it should I choose to.
7142 <filename>user.action</filename> is generally the best place to define
7143 exceptions and additions to the default policies of
7144 <filename>default.action</filename>. Some actions are safe to have their
7145 default policies set here though. So let's set a default policy to have a
7146 <quote>blank</quote> image as opposed to the checkerboard pattern for
7147 <emphasis>ALL</emphasis> sites. <quote>/</quote> of course matches all URL
7152 { +<link linkend="set-image-blocker">set-image-blocker{blank}</link> }
7153 / # ALL sites</screen>
7158 <!-- ~ End section ~ -->
7162 <!-- ~ End section ~ -->
7164 <!-- ~~~~~~~~ New section Header ~~~~~~~~~ -->
7166 <sect1 id="filter-file">
7167 <title>Filter Files</title>
7170 On-the-fly text substitutions need
7171 to be defined in a <quote>filter file</quote>. Once defined, they
7172 can then be invoked as an <quote>action</quote>.
7176 &my-app; supports four different pcrs-based filter actions:
7177 <literal><link linkend="filter">filter</link></literal> to
7178 rewrite the content that is send to the client,
7179 <literal><link linkend="client-header-filter">client-header-filter</link></literal>
7180 to rewrite headers that are send by the client,
7181 <literal><link linkend="server-header-filter">server-header-filter</link></literal>
7182 to rewrite headers that are send by the server, and
7183 <literal><link linkend="client-body-filter">client-body-filter</link></literal>
7184 to rewrite client request body.
7188 &my-app; also supports three tagger actions:
7189 <literal><link linkend="client-header-tagger">client-header-tagger</link></literal>,
7190 <literal><link linkend="client-body-tagger">client-body-tagger</link></literal>
7192 <literal><link linkend="server-header-tagger">server-header-tagger</link></literal>.
7193 Taggers and filters use the same syntax in the filter files, the difference
7194 is that taggers don't modify the text they are filtering, but use a rewritten
7195 version of the filtered text as tag. The tags can then be used to change the
7196 applying actions through sections with <link linkend="tag-pattern">tag-patterns</link>.
7200 Finally &my-app; supports the
7201 <literal><link linkend="external-filter">external-filter</link></literal> action
7202 to enable <literal><link linkend="external-filter-syntax">external filters</link></literal>
7203 written in proper programming languages.
7208 Multiple filter files can be defined through the <literal> <link
7209 linkend="filterfile">filterfile</link></literal> config directive. The filters
7210 as supplied by the developers are located in
7211 <filename>default.filter</filename>. It is recommended that any locally
7212 defined or modified filters go in a separately defined file such as
7213 <filename>user.filter</filename>.
7217 Common tasks for content filters are to eliminate common annoyances in
7218 HTML and JavaScript, such as pop-up windows,
7219 exit consoles, crippled windows without navigation tools, the
7220 infamous <BLINK> tag etc, to suppress images with certain
7221 width and height attributes (standard banner sizes or web-bugs),
7222 or just to have fun.
7226 Enabled content filters are applied to any content whose
7227 <quote>Content Type</quote> header is recognised as a sign
7228 of text-based content, with the exception of <literal>text/plain</literal>.
7229 Use the <link linkend="FORCE-TEXT-MODE">force-text-mode</link> action
7230 to also filter other content.
7234 Substitutions are made at the source level, so if you want to <quote>roll
7235 your own</quote> filters, you should first be familiar with HTML syntax,
7236 and, of course, regular expressions.
7240 Just like the <link linkend="actions-file">actions files</link>, the
7241 filter file is organized in sections, which are called <emphasis>filters</emphasis>
7242 here. Each filter consists of a heading line, that starts with one of the
7243 <emphasis>keywords</emphasis> <literal>FILTER:</literal>,
7244 <literal>CLIENT-HEADER-FILTER:</literal>, <literal>SERVER-HEADER-FILTER:</literal> or
7245 <literal>CLIENT-BODY-FILTER:</literal>
7246 followed by the filter's <emphasis>name</emphasis>, and a short (one line)
7247 <emphasis>description</emphasis> of what it does. Below that line
7248 come the <emphasis>jobs</emphasis>, i.e. lines that define the actual
7249 text substitutions. By convention, the name of a filter
7250 should describe what the filter <emphasis>eliminates</emphasis>. The
7251 comment is used in the <ulink url="http://config.privoxy.org/">web-based
7252 user interface</ulink>.
7256 Once a filter called <replaceable>name</replaceable> has been defined
7257 in the filter file, it can be invoked by using an action of the form
7258 +<literal><link linkend="filter">filter</link>{<replaceable>name</replaceable>}</literal>
7259 in any <link linkend="actions-file">actions file</link>.
7263 Filter definitions start with a header line that contains the filter
7264 type, the filter name and the filter description.
7265 A content filter header line for a filter called <quote>foo</quote> could look
7269 <screen>FILTER: foo Replace all "foo" with "bar"</screen>
7272 Below that line, and up to the next header line, come the jobs that
7273 define what text replacements the filter executes. They are specified
7274 in a syntax that imitates <ulink url="http://www.perl.org/">Perl</ulink>'s
7275 <literal>s///</literal> operator. If you are familiar with Perl, you
7276 will find this to be quite intuitive, and may want to look at the
7277 PCRS documentation for the subtle differences to Perl behaviour.
7281 Most notably, the non-standard option letter <literal>U</literal> is supported,
7282 which turns the default to ungreedy matching (add <literal>?</literal> to
7283 quantifiers to turn them greedy again).
7287 The non-standard option letter <literal>D</literal> (dynamic) allows
7288 to use the variables $host, $origin (the IP address the request came from),
7289 $path, $url and $listen-address (the address on which Privoxy accepted the
7290 client request. Example: 127.0.0.1:8118).
7291 They will be replaced with the value they refer to before the filter
7296 Note that '$' is a bad choice for a delimiter in a dynamic filter as you
7297 might end up with unintended variables if you use a variable name
7298 directly after the delimiter. Variables will be resolved without
7299 escaping anything, therefore you also have to be careful not to chose
7300 delimiters that appear in the replacement text. For example '<' should
7301 be save, while '?' will sooner or later cause conflicts with $url.
7305 The non-standard option letter <literal>T</literal> (trivial) prevents
7306 parsing for backreferences in the substitute. Use it if you want to include
7307 text like '$&' in your substitute without quoting.
7312 <ulink url="https://en.wikipedia.org/wiki/Regular_expressions"><quote>Regular
7313 Expressions</quote></ulink>, you might want to take a look at
7314 the <link linkend="regex">Appendix on regular expressions</link>, and
7315 see the <ulink url="http://perldoc.perl.org/perlre.html">Perl
7317 <ulink url="http://perldoc.perl.org/perlop.html">the
7318 <literal>s///</literal> operator's syntax</ulink> and <ulink
7319 url="http://perldoc.perl.org/perlre.html">Perl-style regular
7320 expressions</ulink> in general.
7321 The below examples might also help to get you started.
7325 <!-- ~~~~~~~~ New section Header ~~~~~~~~~ -->
7327 <sect2 id="filter-file-tut"><title>Filter File Tutorial</title>
7329 Now, let's complete our <quote>foo</quote> content filter. We have already defined
7330 the heading, but the jobs are still missing. Since all it does is to replace
7331 <quote>foo</quote> with <quote>bar</quote>, there is only one (trivial) job
7335 <screen>s/foo/bar/</screen>
7338 But wait! Didn't the comment say that <emphasis>all</emphasis> occurrences
7339 of <quote>foo</quote> should be replaced? Our current job will only take
7340 care of the first <quote>foo</quote> on each page. For global substitution,
7341 we'll need to add the <literal>g</literal> option:
7344 <screen>s/foo/bar/g</screen>
7347 Our complete filter now looks like this:
7350 <screen>FILTER: foo Replace all "foo" with "bar"
7351 s/foo/bar/g</screen>
7354 Let's look at some real filters for more interesting examples. Here you see
7355 a filter that protects against some common annoyances that arise from JavaScript
7356 abuse. Let's look at its jobs one after the other:
7361 FILTER: js-annoyances Get rid of particularly annoying JavaScript abuse
7363 # Get rid of JavaScript referrer tracking. Test page: http://www.randomoddness.com/untitled.htm
7365 s|(<script.*)document\.referrer(.*</script>)|$1"Not Your Business!"$2|Usg</screen>
7368 Following the header line and a comment, you see the job. Note that it uses
7369 <literal>|</literal> as the delimiter instead of <literal>/</literal>, because
7370 the pattern contains a forward slash, which would otherwise have to be escaped
7371 by a backslash (<literal>\</literal>).
7375 Now, let's examine the pattern: it starts with the text <literal><script.*</literal>
7376 enclosed in parentheses. Since the dot matches any character, and <literal>*</literal>
7377 means: <quote>Match an arbitrary number of the element left of myself</quote>, this
7378 matches <quote><script</quote>, followed by <emphasis>any</emphasis> text, i.e.
7379 it matches the whole page, from the start of the first <script> tag.
7383 That's more than we want, but the pattern continues: <literal>document\.referrer</literal>
7384 matches only the exact string <quote>document.referrer</quote>. The dot needed to
7385 be <emphasis>escaped</emphasis>, i.e. preceded by a backslash, to take away its
7386 special meaning as a joker, and make it just a regular dot. So far, the meaning is:
7387 Match from the start of the first <script> tag in a the page, up to, and including,
7388 the text <quote>document.referrer</quote>, if <emphasis>both</emphasis> are present
7389 in the page (and appear in that order).
7393 But there's still more pattern to go. The next element, again enclosed in parentheses,
7394 is <literal>.*</script></literal>. You already know what <literal>.*</literal>
7395 means, so the whole pattern translates to: Match from the start of the first <script>
7396 tag in a page to the end of the last <script> tag, provided that the text
7397 <quote>document.referrer</quote> appears somewhere in between.
7401 This is still not the whole story, since we have ignored the options and the parentheses:
7402 The portions of the page matched by sub-patterns that are enclosed in parentheses, will be
7403 remembered and be available through the variables <literal>$1, $2, ...</literal> in
7404 the substitute. The <literal>U</literal> option switches to ungreedy matching, which means
7405 that the first <literal>.*</literal> in the pattern will only <quote>eat up</quote> all
7406 text in between <quote><script</quote> and the <emphasis>first</emphasis> occurrence
7407 of <quote>document.referrer</quote>, and that the second <literal>.*</literal> will
7408 only span the text up to the <emphasis>first</emphasis> <quote></script></quote>
7409 tag. Furthermore, the <literal>s</literal> option says that the match may span
7410 multiple lines in the page, and the <literal>g</literal> option again means that the
7411 substitution is global.
7415 So, to summarize, the pattern means: Match all scripts that contain the text
7416 <quote>document.referrer</quote>. Remember the parts of the script from
7417 (and including) the start tag up to (and excluding) the string
7418 <quote>document.referrer</quote> as <literal>$1</literal>, and the part following
7419 that string, up to and including the closing tag, as <literal>$2</literal>.
7423 Now the pattern is deciphered, but wasn't this about substituting things? So
7424 lets look at the substitute: <literal>$1"Not Your Business!"$2</literal> is
7425 easy to read: The text remembered as <literal>$1</literal>, followed by
7426 <literal>"Not Your Business!"</literal> (<emphasis>including</emphasis>
7427 the quotation marks!), followed by the text remembered as <literal>$2</literal>.
7428 This produces an exact copy of the original string, with the middle part
7429 (the <quote>document.referrer</quote>) replaced by <literal>"Not Your
7430 Business!"</literal>.
7434 The whole job now reads: Replace <quote>document.referrer</quote> by
7435 <literal>"Not Your Business!"</literal> wherever it appears inside a
7436 <script> tag. Note that this job won't break JavaScript syntax,
7437 since both the original and the replacement are syntactically valid
7438 string objects. The script just won't have access to the referrer
7439 information anymore.
7443 We'll show you two other jobs from the JavaScript taming department, but
7444 this time only point out the constructs of special interest:
7448 # The status bar is for displaying link targets, not pointless blahblah
7450 s/window\.status\s*=\s*(['"]).*?\1/dUmMy=1/ig</screen>
7453 <literal>\s</literal> stands for whitespace characters (space, tab, newline,
7454 carriage return, form feed), so that <literal>\s*</literal> means: <quote>zero
7455 or more whitespace</quote>. The <literal>?</literal> in <literal>.*?</literal>
7456 makes this matching of arbitrary text ungreedy. (Note that the <literal>U</literal>
7457 option is not set). The <literal>['"]</literal> construct means: <quote>a single
7458 <emphasis>or</emphasis> a double quote</quote>. Finally, <literal>\1</literal> is
7459 a back-reference to the first parenthesis just like <literal>$1</literal> above,
7460 with the difference that in the <emphasis>pattern</emphasis>, a backslash indicates
7461 a back-reference, whereas in the <emphasis>substitute</emphasis>, it's the dollar.
7465 So what does this job do? It replaces assignments of single- or double-quoted
7466 strings to the <quote>window.status</quote> object with a dummy assignment
7467 (using a variable name that is hopefully odd enough not to conflict with
7468 real variables in scripts). Thus, it catches many cases where e.g. pointless
7469 descriptions are displayed in the status bar instead of the link target when
7470 you move your mouse over links.
7474 # Kill OnUnload popups. Yummy. Test: http://www.zdnet.com/zdsubs/yahoo/tree/yfs.html
7476 s/(<body [^>]*)onunload(.*>)/$1never$2/iU</screen>
7480 <ulink url="http://www.w3.org/TR/2000/REC-DOM-Level-2-Events-20001113/events.html#Events-eventgroupings-htmlevents">OnUnload
7481 event binding</ulink> in the HTML DOM was a <emphasis>CRIME</emphasis>.
7482 When I close a browser window, I want it to close and die. Basta.
7483 This job replaces the <quote>onunload</quote> attribute in
7484 <quote><body></quote> tags with the dummy word <literal>never</literal>.
7485 Note that the <literal>i</literal> option makes the pattern matching
7486 case-insensitive. Also note that ungreedy matching alone doesn't always guarantee
7487 a minimal match: In the first parenthesis, we had to use <literal>[^>]*</literal>
7488 instead of <literal>.*</literal> to prevent the match from exceeding the
7489 <body> tag if it doesn't contain <quote>OnUnload</quote>, but the page's
7494 The last example is from the fun department:
7498 FILTER: fun Fun text replacements
7500 # Spice the daily news:
7502 s/microsoft(?!\.com)/MicroSuck/ig</screen>
7505 Note the <literal>(?!\.com)</literal> part (a so-called negative lookahead)
7506 in the job's pattern, which means: Don't match, if the string
7507 <quote>.com</quote> appears directly following <quote>microsoft</quote>
7508 in the page. This prevents links to microsoft.com from being trashed, while
7509 still replacing the word everywhere else.
7513 # Buzzword Bingo (example for extended regex syntax)
7515 s* industry[ -]leading \
7517 | customer[ -]focused \
7518 | market[ -]driven \
7519 | award[ -]winning # Comments are OK, too! \
7520 | high[ -]performance \
7521 | solutions[ -]based \
7525 *<font color="red"><b>BINGO!</b></font> \
7529 The <literal>x</literal> option in this job turns on extended syntax, and allows for
7530 e.g. the liberal use of (non-interpreted!) whitespace for nicer formatting.
7538 <!-- ~~~~~~~~ New section Header ~~~~~~~~~ -->
7540 <sect2 id="predefined-filters"><title>The Pre-defined Filters</title>
7544 Note each filter is also listed in the +filter action section above. Please
7545 keep these listings in sync.
7550 The distribution <filename>default.filter</filename> file contains a selection of
7551 pre-defined filters for your convenience:
7556 <term><emphasis>js-annoyances</emphasis></term>
7559 The purpose of this filter is to get rid of particularly annoying JavaScript abuse.
7565 replaces JavaScript references to the browser's referrer information
7566 with the string "Not Your Business!". This compliments the <literal><link
7567 linkend="hide-referrer">hide-referrer</link></literal> action on the content level.
7572 removes the bindings to the DOM's
7573 <ulink url="http://www.w3.org/TR/2000/REC-DOM-Level-2-Events-20001113/events.html#Events-eventgroupings-htmlevents">unload
7574 event</ulink> which we feel has no right to exist and is responsible for most <quote>exit consoles</quote>, i.e.
7575 nasty windows that pop up when you close another one.
7580 removes code that causes new windows to be opened with undesired properties, such as being
7581 full-screen, non-resizeable, without location, status or menu bar etc.
7586 Use with caution. This is an aggressive filter, and can break sites that
7587 rely heavily on JavaScript.
7593 <term><emphasis>js-events</emphasis></term>
7596 This is a very radical measure. It removes virtually all JavaScript event bindings, which
7597 means that scripts can not react to user actions such as mouse movements or clicks, window
7598 resizing etc, anymore. Use with caution!
7601 We <emphasis>strongly discourage</emphasis> using this filter as a default since it breaks
7602 many legitimate scripts. It is meant for use only on extra-nasty sites (should you really
7609 <term><emphasis>html-annoyances</emphasis></term>
7612 This filter will undo many common instances of HTML based abuse.
7615 The <literal>BLINK</literal> and <literal>MARQUEE</literal> tags
7616 are neutralized (yeah baby!), and browser windows will be created as
7617 resizeable (as of course they should be!), and will have location,
7618 scroll and menu bars -- even if specified otherwise.
7624 <term><emphasis>content-cookies</emphasis></term>
7627 Most cookies are set in the HTTP dialog, where they can be intercepted
7629 <literal><link linkend="crunch-incoming-cookies">crunch-incoming-cookies</link></literal>
7630 and <literal><link linkend="crunch-outgoing-cookies">crunch-outgoing-cookies</link></literal>
7631 actions. But web sites increasingly make use of HTML meta tags and JavaScript
7632 to sneak cookies to the browser on the content level.
7635 This filter disables most HTML and JavaScript code that reads or sets
7636 cookies. It cannot detect all clever uses of these types of code, so it
7637 should not be relied on as an absolute fix. Use it wherever you would also
7638 use the cookie crunch actions.
7644 <term><emphasis>refresh-tags</emphasis></term>
7647 Disable any refresh tags if the interval is greater than nine seconds (so
7648 that redirections done via refresh tags are not destroyed). This is useful
7649 for dial-on-demand setups, or for those who find this HTML feature
7656 <term><emphasis>unsolicited-popups</emphasis></term>
7659 This filter attempts to prevent only <quote>unsolicited</quote> pop-up
7660 windows from opening, yet still allow pop-up windows that the user
7661 has explicitly chosen to open. It was added in version 3.0.1,
7662 as an improvement over earlier such filters.
7665 Technical note: The filter works by redefining the window.open JavaScript
7666 function to a dummy function, <literal>PrivoxyWindowOpen()</literal>,
7667 during the loading and rendering phase of each HTML page access, and
7668 restoring the function afterward.
7671 This is recommended only for browsers that cannot perform this function
7672 reliably themselves. And be aware that some sites require such windows
7673 in order to function normally. Use with caution.
7679 <term><emphasis>all-popups</emphasis></term>
7682 Attempt to prevent <emphasis>all</emphasis> pop-up windows from opening.
7683 Note this should be used with even more discretion than the above, since
7684 it is more likely to break some sites that require pop-ups for normal
7685 usage. Use with caution.
7691 <term><emphasis>img-reorder</emphasis></term>
7694 This is a helper filter that has no value if used alone. It makes the
7695 <literal>banners-by-size</literal> and <literal>banners-by-link</literal>
7696 (see below) filters more effective and should be enabled together with them.
7702 <term><emphasis>banners-by-size</emphasis></term>
7705 This filter removes image tags purely based on what size they are. Fortunately
7706 for us, many ads and banner images tend to conform to certain standardized
7707 sizes, which makes this filter quite effective for ad stripping purposes.
7710 Occasionally this filter will cause false positives on images that are not ads,
7711 but just happen to be of one of the standard banner sizes.
7714 Recommended only for those who require extreme ad blocking. The default
7715 block rules should catch 95+% of all ads <emphasis>without</emphasis> this filter enabled.
7721 <term><emphasis>banners-by-link</emphasis></term>
7724 This filter attempts to kill any banners if their URLs seem to point
7725 to known or suspected click trackers. It is currently not of much value
7726 and is not recommended for use by default.
7732 <term><emphasis>webbugs</emphasis></term>
7735 Webbugs are small, invisible images (technically 1X1 GIF images), that
7736 are used to track users across websites, and collect information on them.
7737 As an HTML page is loaded by the browser, an embedded image tag causes the
7738 browser to contact a third-party site, disclosing the tracking information
7739 through the requested URL and/or cookies for that third-party domain, without
7740 the user ever becoming aware of the interaction with the third-party site.
7741 HTML-ized spam also uses a similar technique to verify email addresses.
7744 This filter removes the HTML code that loads such <quote>webbugs</quote>.
7750 <term><emphasis>tiny-textforms</emphasis></term>
7753 A rather special-purpose filter that can be used to enlarge textareas (those
7754 multi-line text boxes in web forms) and turn off hard word wrap in them.
7755 It was written for the sourceforge.net tracker system where such boxes are
7756 a nuisance, but it can be handy on other sites, too.
7759 It is not recommended to use this filter as a default.
7765 <term><emphasis>jumping-windows</emphasis></term>
7768 Many consider windows that move, or resize themselves to be abusive. This filter
7769 neutralizes the related JavaScript code. Note that some sites might not display
7770 or behave as intended when using this filter. Use with caution.
7776 <term><emphasis>frameset-borders</emphasis></term>
7779 Some web designers seem to assume that everyone in the world will view their
7780 web sites using the same browser brand and version, screen resolution etc,
7781 because only that assumption could explain why they'd use static frame sizes,
7782 yet prevent their frames from being resized by the user, should they be too
7783 small to show their whole content.
7786 This filter removes the related HTML code. It should only be applied to sites
7793 <term><emphasis>demoronizer</emphasis></term>
7796 Many Microsoft products that generate HTML use non-standard extensions (read:
7797 violations) of the ISO 8859-1 aka Latin-1 character set. This can cause those
7798 HTML documents to display with errors on standard-compliant platforms.
7801 This filter translates the MS-only characters into Latin-1 equivalents.
7802 It is not necessary when using MS products, and will cause corruption of
7803 all documents that use 8-bit character sets other than Latin-1. It's mostly
7804 worthwhile for Europeans on non-MS platforms, if weird garbage characters
7805 sometimes appear on some pages, or user agents that don't correct for this on
7808 My version of Mozilla (ancient) shows little square boxes for quote
7809 characters, and apostrophes on moronized pages. So many pages have this, I
7810 can read them fine now. HB 08/27/06
7817 <term><emphasis>shockwave-flash</emphasis></term>
7820 A filter for shockwave haters. As the name suggests, this filter strips code
7821 out of web pages that is used to embed shockwave flash objects.
7829 <term><emphasis>quicktime-kioskmode</emphasis></term>
7832 Change HTML code that embeds Quicktime objects so that kioskmode, which
7833 prevents saving, is disabled.
7839 <term><emphasis>fun</emphasis></term>
7842 Text replacements for subversive browsing fun. Make fun of your favorite
7843 Monopolist or play buzzword bingo.
7849 <term><emphasis>crude-parental</emphasis></term>
7852 A demonstration-only filter that shows how <application>Privoxy</application>
7853 can be used to delete web content on a keyword basis.
7859 <term><emphasis>ie-exploits</emphasis></term>
7862 An experimental collection of text replacements to disable malicious HTML and JavaScript
7863 code that exploits known security holes in Internet Explorer.
7866 Presently, it only protects against Nimda and a cross-site scripting bug, and
7867 would need active maintenance to provide more substantial protection.
7873 <term><emphasis>site-specifics</emphasis></term>
7876 Some web sites have very specific problems, the cure for which doesn't apply
7877 anywhere else, or could even cause damage on other sites.
7880 This is a collection of such site-specific cures which should only be applied
7881 to the sites they were intended for, which is what the supplied
7882 <filename>default.action</filename> file does. Users shouldn't need to change
7883 anything regarding this filter.
7889 <term><emphasis>google</emphasis></term>
7892 A CSS based block for Google text ads. Also removes a width limitation
7893 and the toolbar advertisement.
7899 <term><emphasis>yahoo</emphasis></term>
7902 Another CSS based block, this time for Yahoo text ads. And removes
7903 a width limitation as well.
7909 <term><emphasis>msn</emphasis></term>
7912 Another CSS based block, this time for MSN text ads. And removes
7913 tracking URLs, as well as a width limitation.
7919 <term><emphasis>blogspot</emphasis></term>
7922 Cleans up some Blogspot blogs. Read the fine print before using this one!
7925 This filter also intentionally removes some navigation stuff and sets the
7926 page width to 100%. As a result, some rounded <quote>corners</quote> would
7927 appear to early or not at all and as fixing this would require a browser
7928 that understands background-size (CSS3), they are removed instead.
7934 <term><emphasis>xml-to-html</emphasis></term>
7937 Server-header filter to change the Content-Type from xml to html.
7943 <term><emphasis>html-to-xml</emphasis></term>
7946 Server-header filter to change the Content-Type from html to xml.
7952 <term><emphasis>no-ping</emphasis></term>
7955 Removes the non-standard <literal>ping</literal> attribute from
7956 anchor and area HTML tags.
7962 <term><emphasis>hide-tor-exit-notation</emphasis></term>
7965 Client-header filter to remove the <command>Tor</command> exit node notation
7966 found in Host and Referer headers.
7969 If &my-app; and <command>Tor</command> are chained and &my-app;
7970 is configured to use socks4a, one can use <quote>http://www.example.org.foobar.exit/</quote>
7971 to access the host <quote>www.example.org</quote> through the
7972 <command>Tor</command> exit node <quote>foobar</quote>.
7975 As the HTTP client isn't aware of this notation, it treats the
7976 whole string <quote>www.example.org.foobar.exit</quote> as host and uses it
7977 for the <quote>Host</quote> and <quote>Referer</quote> headers. From the
7978 server's point of view the resulting headers are invalid and can cause problems.
7981 An invalid <quote>Referer</quote> header can trigger <quote>hot-linking</quote>
7982 protections, an invalid <quote>Host</quote> header will make it impossible for
7983 the server to find the right vhost (several domains hosted on the same IP address).
7986 This client-header filter removes the <quote>foo.exit</quote> part in those headers
7987 to prevent the mentioned problems. Note that it only modifies
7988 the HTTP headers, it doesn't make it impossible for the server
7989 to detect your <command>Tor</command> exit node based on the IP address
7990 the request is coming from.
7997 <term><emphasis> </emphasis></term>
8010 <!-- ~~~~~~~~ New section Header ~~~~~~~~~ -->
8011 <sect2 id="external-filter-syntax"><title>External filter syntax</title>
8013 External filters are scripts or programs that can modify the content in
8014 case common <literal><link linkend="filter">filters</link></literal>
8015 aren't powerful enough.
8018 External filters can be written in any language the platform &my-app; runs
8022 They are controlled with the
8023 <literal><link linkend="external-filter">external-filter</link></literal> action
8024 and have to be defined in the <literal><link linkend="filterfile">filterfile</link></literal>
8028 The header looks like any other filter, but instead of pcrs jobs, external
8029 filters contain a single job which can be a program or a shell script (which
8030 may call other scripts or programs).
8033 External filters read the content from STDIN and write the rewritten
8035 The environment variables PRIVOXY_URL, PRIVOXY_PATH, PRIVOXY_HOST,
8036 PRIVOXY_ORIGIN, PRIVOXY_LISTEN_ADDRESS can be used to get some details
8037 about the client request.
8040 &my-app; will temporary store the content to filter in the
8041 <literal><link linkend="temporary-directory">temporary-directory</link></literal>.
8045 EXTERNAL-FILTER: cat Pointless example filter that doesn't actually modify the content
8048 # Incorrect reimplementation of the filter above in POSIX shell.
8050 # Note that it's a single job that spans multiple lines, the line
8051 # breaks are not passed to the shell, thus the semicolons are required.
8053 # If the script isn't trivial, it is recommended to put it into an external file.
8055 # In general, writing external filters entirely in POSIX shell is not
8056 # considered a good idea.
8057 EXTERNAL-FILTER: cat2 Pointless example filter that despite its name may actually modify the content
8063 EXTERNAL-FILTER: rotate-image Rotate an image by 180 degree. Test filter with limited value.
8064 /usr/local/bin/convert - -rotate 180 -
8066 EXTERNAL-FILTER: citation-needed Adds a "[citation needed]" tag to an image. The coordinates may need adjustment.
8067 /usr/local/bin/convert - -pointsize 16 -fill white -annotate +17+418 "[citation needed]" -
8072 Currently external filters are executed with &my-app;'s privileges!
8073 Only use external filters you understand and trust.
8077 External filters are experimental and the syntax may change in the future.
8083 <!-- ~ End section ~ -->
8087 <!-- ~~~~~ New section ~~~~~ -->
8089 <sect1 id="templates">
8090 <title>Privoxy's Template Files</title>
8092 All <application>Privoxy</application> built-in pages, i.e. error pages such as the
8093 <ulink url="http://show-the-404-error.page"><quote>404 - No Such Domain</quote>
8094 error page</ulink>, the <ulink
8095 url="http://ads.bannerserver.example.com/nasty-ads/sponsor.html"><quote>BLOCKED</quote>
8097 and all pages of its <ulink url="http://config.privoxy.org/">web-based
8098 user interface</ulink>, are generated from <emphasis>templates</emphasis>.
8099 (<application>Privoxy</application> must be running for the above links to work as
8104 These templates are stored in a subdirectory of the <link linkend="confdir">configuration
8105 directory</link> called <filename>templates</filename>. On Unixish platforms,
8107 <ulink url="file:///etc/privoxy/templates/"><filename>/etc/privoxy/templates/</filename></ulink>.
8111 The templates are basically normal HTML files, but with place-holders (called symbols
8112 or exports), which <application>Privoxy</application> fills at run time. It
8113 is possible to edit the templates with a normal text editor, should you want
8114 to customize them. (<emphasis>Not recommended for the casual
8115 user</emphasis>). Should you create your own custom templates, you should use
8116 the <filename>config</filename> setting <link linkend="templdir">templdir</link>
8117 to specify an alternate location, so your templates do not get overwritten
8121 Note that just like in configuration files, lines starting
8122 with <literal>#</literal> are ignored when the templates are filled in.
8126 The place-holders are of the form <literal>@name@</literal>, and you will
8127 find a list of available symbols, which vary from template to template,
8128 in the comments at the start of each file. Note that these comments are not
8129 always accurate, and that it's probably best to look at the existing HTML
8130 code to find out which symbols are supported and what they are filled in with.
8134 A special application of this substitution mechanism is to make whole
8135 blocks of HTML code disappear when a specific symbol is set. We use this
8136 for many purposes, one of them being to include the beta warning in all
8137 our user interface (CGI) pages when <application>Privoxy</application>
8138 is in an alpha or beta development stage:
8142 <!-- @if-unstable-start -->
8144 ... beta warning HTML code goes here ...
8146 <!-- if-unstable-end@ --></screen>
8149 If the "unstable" symbol is set, everything in between and including
8150 <literal>@if-unstable-start</literal> and <literal>if-unstable-end@</literal>
8151 will disappear, leaving nothing but an empty comment:
8154 <screen><!-- --></screen>
8157 There's also an if-then-else construct and an <literal>#include</literal>
8158 mechanism, but you'll sure find out if you are inclined to edit the
8163 All templates refer to a style located at
8164 <ulink url="http://config.privoxy.org/send-stylesheet"><literal>http://config.privoxy.org/send-stylesheet</literal></ulink>.
8165 This is, of course, locally served by <application>Privoxy</application>
8166 and the source for it can be found and edited in the
8167 <filename>cgi-style.css</filename> template.
8172 <!-- ~ End section ~ -->
8176 <!-- ~~~~~ New section ~~~~~ -->
8178 <sect1 id="contact"><title>Contacting the Developers, Bug Reporting and Feature
8181 <!-- Include contacting.sgml boilerplate: -->
8183 <!-- end boilerplate -->
8187 <!-- ~ End section ~ -->
8190 <!-- ~~~~~ New section ~~~~~ -->
8191 <sect1 id="copyright"><title>Privoxy Copyright, License and History</title>
8193 <!-- Include copyright.sgml: -->
8195 <!-- end copyright -->
8198 <application>Privoxy</application> is free software; you can
8199 redistribute and/or modify its source code under the terms
8200 of the <citetitle>GNU General Public License</citetitle>
8201 as published by the Free Software Foundation, either version 2
8202 of the license, or (at your option) any later version.
8206 The same is true for <application>Privoxy</application> binaries
8207 unless they are linked with a
8208 <ulink url="https://www.trustedfirmware.org/projects/mbed-tls/">mbed TLS</ulink> version
8209 that is licensed under the Apache 2.0 license in which
8210 case you can redistribute and/or modify the <application>Privoxy</application>
8211 binaries under the terms of the <citetitle>GNU General Public License</citetitle>
8212 as published by the Free Software Foundation, either version 3
8213 of the license, or (at your option) any later version.
8217 Both licenses are included in the next section.
8220 <!-- ~~~~~ New section ~~~~~ -->
8221 <sect2 id="license"><title>License</title>
8223 <sect3 id="gplv2"><title>GNU General Public License version 2</title>
8224 <literallayout class="Monospaced"><![ RCDATA [ &GPLv2; ]]></literallayout>
8227 <sect3 id="gplv3"><title>GNU General Public License version 3</title>
8228 <literallayout class="Monospaced"><![ RCDATA [ &GPLv3; ]]></literallayout>
8231 <sect3 id="third-party-licenses"><title>Third-party licenses and copyrights</title>
8233 Privoxy depends on a couple of third-party libraries which have seperate licenses.
8234 Please refer to the third-party websites for up-to-date license and copyright
8238 Privoxy depends on <ulink url="https://pcre.org/">pcre</ulink>.
8241 When compiled with FEATURE_BROTLI (optional), Privoxy depends on
8242 <ulink url="https://www.brotli.org/">brotli</ulink>.
8245 When compiled with FEATURE_HTTPS_INSPECTION (optional),
8246 Privoxy depends on a TLS library. The supported libraries are
8247 <ulink url="https://www.openssl.org/">LibreSSL</ulink>,
8248 <ulink url="https://github.com/Mbed-TLS/mbedtls/tags">mbed TLS 2.28.x</ulink> and
8249 <ulink url="https://www.openssl.org/">OpenSSL</ulink>.
8252 When compiled with FEATURE_ZLIB (optional),
8253 Privoxy depends on <ulink url="https://zlib.net/">zlib</ulink>.
8258 <!-- ~ End section ~ -->
8261 <!-- ~~~~~ New section ~~~~~ -->
8263 <sect2 id="history"><title>History</title>
8264 <!-- Include history.sgml: -->
8266 <!-- end history -->
8269 <sect2 id="authors"><title>Authors</title>
8270 <!-- Include p-authors.sgml: -->
8272 <!-- end authors -->
8277 <!-- ~ End section ~ -->
8280 <!-- ~~~~~ New section ~~~~~ -->
8281 <sect1 id="seealso"><title>See Also</title>
8282 <!-- Include seealso.sgml: -->
8284 <!-- end seealso -->
8289 <!-- ~~~~~ New section ~~~~~ -->
8290 <sect1 id="appendix"><title>Appendix</title>
8293 <!-- ~~~~~ New section ~~~~~ -->
8295 <title>Regular Expressions</title>
8297 <application>Privoxy</application> uses Perl-style <quote>regular
8298 expressions</quote> in its <link linkend="actions-file">actions
8299 files</link> and <link linkend="filter-file">filter file</link>,
8300 through the <ulink url="http://www.pcre.org/">PCRE</ulink> and
8303 <ulink url="http://www.oesterhelt.org/pcrs/">PCRS</ulink> libraries.
8305 <application>PCRS</application> libraries.
8309 If you are reading this, you probably don't understand what <quote>regular
8310 expressions</quote> are, or what they can do. So this will be a very brief
8311 introduction only. A full explanation would require a <ulink
8312 url="http://www.oreilly.com/catalog/regex/">book</ulink> ;-)
8316 Regular expressions provide a language to describe patterns that can be
8317 run against strings of characters (letter, numbers, etc), to see if they
8318 match the string or not. The patterns are themselves (sometimes complex)
8319 strings of literal characters, combined with wild-cards, and other special
8320 characters, called meta-characters. The <quote>meta-characters</quote> have
8321 special meanings and are used to build complex patterns to be matched against.
8322 Perl Compatible Regular Expressions are an especially convenient
8323 <quote>dialect</quote> of the regular expression language.
8327 To make a simple analogy, we do something similar when we use wild-card
8328 characters when listing files with the <command>dir</command> command in DOS.
8329 <literal>*.*</literal> matches all filenames. The <quote>special</quote>
8330 character here is the asterisk which matches any and all characters. We can be
8331 more specific and use <literal>?</literal> to match just individual
8332 characters. So <quote>dir file?.text</quote> would match
8333 <quote>file1.txt</quote>, <quote>file2.txt</quote>, etc. We are pattern
8334 matching, using a similar technique to <quote>regular expressions</quote>!
8338 Regular expressions do essentially the same thing, but are much, much more
8339 powerful. There are many more <quote>special characters</quote> and ways of
8340 building complex patterns however. Let's look at a few of the common ones,
8341 and then some examples:
8346 <emphasis>.</emphasis> - Matches any single character, e.g. <quote>a</quote>,
8347 <quote>A</quote>, <quote>4</quote>, <quote>:</quote>, or <quote>@</quote>.
8353 <emphasis>?</emphasis> - The preceding character or expression is matched ZERO or ONE
8360 <emphasis>+</emphasis> - The preceding character or expression is matched ONE or MORE
8367 <emphasis>*</emphasis> - The preceding character or expression is matched ZERO or MORE
8374 <emphasis>\</emphasis> - The <quote>escape</quote> character denotes that
8375 the following character should be taken literally. This is used where one of the
8376 special characters (e.g. <quote>.</quote>) needs to be taken literally and
8377 not as a special meta-character. Example: <quote>example\.com</quote>, makes
8378 sure the period is recognized only as a period (and not expanded to its
8379 meta-character meaning of any single character).
8385 <emphasis>[ ]</emphasis> - Characters enclosed in brackets will be matched if
8386 any of the enclosed characters are encountered. For instance, <quote>[0-9]</quote>
8387 matches any numeric digit (zero through nine). As an example, we can combine
8388 this with <quote>+</quote> to match any digit one of more times: <quote>[0-9]+</quote>.
8394 <emphasis>( )</emphasis> - parentheses are used to group a sub-expression,
8395 or multiple sub-expressions.
8401 <emphasis>|</emphasis> - The <quote>bar</quote> character works like an
8402 <quote>or</quote> conditional statement. A match is successful if the
8403 sub-expression on either side of <quote>|</quote> matches. As an example:
8404 <quote>/(this|that) example/</quote> uses grouping and the bar character
8405 and would match either <quote>this example</quote> or <quote>that
8406 example</quote>, and nothing else.
8411 These are just some of the ones you are likely to use when matching URLs with
8412 <application>Privoxy</application>, and is a long way from a definitive
8413 list. This is enough to get us started with a few simple examples which may
8414 be more illuminating:
8418 <emphasis><literal>/.*/banners/.*</literal></emphasis> - A simple example
8419 that uses the common combination of <quote>.</quote> and <quote>*</quote> to
8420 denote any character, zero or more times. In other words, any string at all.
8421 So we start with a literal forward slash, then our regular expression pattern
8422 (<quote>.*</quote>) another literal forward slash, the string
8423 <quote>banners</quote>, another forward slash, and lastly another
8424 <quote>.*</quote>. We are building
8425 a directory path here. This will match any file with the path that has a
8426 directory named <quote>banners</quote> in it. The <quote>.*</quote> matches
8427 any characters, and this could conceivably be more forward slashes, so it
8428 might expand into a much longer looking path. For example, this could match:
8429 <quote>/eye/hate/spammers/banners/annoy_me_please.gif</quote>, or just
8430 <quote>/banners/annoying.html</quote>, or almost an infinite number of other
8431 possible combinations, just so it has <quote>banners</quote> in the path
8436 And now something a little more complex:
8440 <emphasis><literal>/.*/adv((er)?ts?|ertis(ing|ements?))?/</literal></emphasis> -
8441 We have several literal forward slashes again (<quote>/</quote>), so we are
8442 building another expression that is a file path statement. We have another
8443 <quote>.*</quote>, so we are matching against any conceivable sub-path, just so
8444 it matches our expression. The only true literal that <emphasis>must
8445 match</emphasis> our pattern is <application>adv</application>, together with
8446 the forward slashes. What comes after the <quote>adv</quote> string is the
8451 Remember the <quote>?</quote> means the preceding expression (either a
8452 literal character or anything grouped with <quote>(...)</quote> in this case)
8453 can exist or not, since this means either zero or one match. So
8454 <quote>((er)?ts?|ertis(ing|ements?))</quote> is optional, as are the
8455 individual sub-expressions: <quote>(er)</quote>,
8456 <quote>(ing|ements?)</quote>, and the <quote>s</quote>. The <quote>|</quote>
8457 means <quote>or</quote>. We have two of those. For instance,
8458 <quote>(ing|ements?)</quote>, can expand to match either <quote>ing</quote>
8459 <emphasis>OR</emphasis> <quote>ements?</quote>. What is being done here, is an
8460 attempt at matching as many variations of <quote>advertisement</quote>, and
8461 similar, as possible. So this would expand to match just <quote>adv</quote>,
8462 or <quote>advert</quote>, or <quote>adverts</quote>, or
8463 <quote>advertising</quote>, or <quote>advertisement</quote>, or
8464 <quote>advertisements</quote>. You get the idea. But it would not match
8465 <quote>advertizements</quote> (with a <quote>z</quote>). We could fix that by
8466 changing our regular expression to:
8467 <quote>/.*/adv((er)?ts?|erti(s|z)(ing|ements?))?/</quote>, which would then match
8472 <emphasis><literal>/.*/advert[0-9]+\.(gif|jpe?g)</literal></emphasis> - Again
8473 another path statement with forward slashes. Anything in the square brackets
8474 <quote>[ ]</quote> can be matched. This is using <quote>0-9</quote> as a
8475 shorthand expression to mean any digit one through nine. It is the same as
8476 saying <quote>0123456789</quote>. So any digit matches. The <quote>+</quote>
8477 means one or more of the preceding expression must be included. The preceding
8478 expression here is what is in the square brackets -- in this case, any digit
8479 one through nine. Then, at the end, we have a grouping: <quote>(gif|jpe?g)</quote>.
8480 This includes a <quote>|</quote>, so this needs to match the expression on
8481 either side of that bar character also. A simple <quote>gif</quote> on one side, and the other
8482 side will in turn match either <quote>jpeg</quote> or <quote>jpg</quote>,
8483 since the <quote>?</quote> means the letter <quote>e</quote> is optional and
8484 can be matched once or not at all. So we are building an expression here to
8485 match image GIF or JPEG type image file. It must include the literal
8486 string <quote>advert</quote>, then one or more digits, and a <quote>.</quote>
8487 (which is now a literal, and not a special character, since it is escaped
8488 with <quote>\</quote>), and lastly either <quote>gif</quote>, or
8489 <quote>jpeg</quote>, or <quote>jpg</quote>. Some possible matches would
8490 include: <quote>//advert1.jpg</quote>,
8491 <quote>/nasty/ads/advert1234.gif</quote>,
8492 <quote>/banners/from/hell/advert99.jpg</quote>. It would not match
8493 <quote>advert1.gif</quote> (no leading slash), or
8494 <quote>/adverts232.jpg</quote> (the expression does not include an
8495 <quote>s</quote>), or <quote>/advert1.jsp</quote> (<quote>jsp</quote> is not
8496 in the expression anywhere).
8500 We are barely scratching the surface of regular expressions here so that you
8501 can understand the default <application>Privoxy</application>
8502 configuration files, and maybe use this knowledge to customize your own
8503 installation. There is much, much more that can be done with regular
8504 expressions. Now that you know enough to get started, you can learn more on
8509 More reading on Perl Compatible Regular expressions:
8510 <ulink url="http://perldoc.perl.org/perlre.html">http://perldoc.perl.org/perlre.html</ulink>
8514 For information on regular expression based substitutions and their applications
8515 in filters, please see the <link linkend="filter-file">filter file tutorial</link>
8520 <!-- ~ End section ~ -->
8523 <!-- ~~~~~ New section ~~~~~ -->
8524 <sect2 id="internal-pages">
8525 <title>Privoxy's Internal Pages</title>
8528 Since <application>Privoxy</application> proxies each requested
8529 web page, it is easy for <application>Privoxy</application> to
8530 trap certain special URLs. In this way, we can talk directly to
8531 <application>Privoxy</application>, and see how it is
8532 configured, see how our rules are being applied, change these
8533 rules and other configuration options, and even turn
8534 <application>Privoxy's</application> filtering off, all with
8539 The URLs listed below are the special ones that allow direct access
8540 to <application>Privoxy</application>. Of course,
8541 <application>Privoxy</application> must be running to access these. If
8542 not, you will get a friendly error message. Internet access is not
8554 <ulink url="http://config.privoxy.org/">http://config.privoxy.org/</ulink>
8558 There is a shortcut: <ulink url="http://p.p/">http://p.p/</ulink> (But it
8559 doesn't provide a fall-back to a real page, in case the request is not
8560 sent through <application>Privoxy</application>)
8566 View and toggle client tags:
8570 <ulink url="http://config.privoxy.org/client-tags">http://config.privoxy.org/client-tags</ulink>
8577 Show information about the current configuration, including viewing and
8578 editing of actions files:
8582 <ulink url="http://config.privoxy.org/show-status">http://config.privoxy.org/show-status</ulink>
8589 Show the browser's request headers:
8593 <ulink url="http://config.privoxy.org/show-request">http://config.privoxy.org/show-request</ulink>
8600 Show which actions apply to a URL and why:
8604 <ulink url="http://config.privoxy.org/show-url-info">http://config.privoxy.org/show-url-info</ulink>
8611 Toggle Privoxy on or off. This feature can be turned off/on in the main
8612 <filename>config</filename> file. When toggled <quote>off</quote>, <quote>Privoxy</quote>
8613 continues to run, but only as a pass-through proxy, with no actions taking
8618 <ulink url="http://config.privoxy.org/toggle">http://config.privoxy.org/toggle</ulink>
8622 Short cuts. Turn off, then on:
8626 <ulink url="http://config.privoxy.org/toggle?set=disable">http://config.privoxy.org/toggle?set=disable</ulink>
8631 <ulink url="http://config.privoxy.org/toggle?set=enable">http://config.privoxy.org/toggle?set=enable</ulink>
8641 <!-- ~~~~~ New section ~~~~~ -->
8643 <title>Chain of Events</title>
8645 Let's take a quick look at how some of <application>Privoxy's</application>
8646 core features are triggered, and the ensuing sequence of events when a web
8647 page is requested by your browser:
8653 First, your web browser requests a web page. The browser knows to send
8654 the request to <application>Privoxy</application>, which will in turn,
8655 relay the request to the remote web server after passing the following
8661 <application>Privoxy</application> traps any request for its own internal CGI
8662 pages (e.g <ulink url="http://p.p/">http://p.p/</ulink>) and sends the CGI page back to the browser.
8667 Next, <application>Privoxy</application> checks to see if the URL
8669 linkend="BLOCK"><quote>+block</quote></link> patterns. If
8670 so, the URL is then blocked, and the remote web server will not be contacted.
8671 <link linkend="HANDLE-AS-IMAGE"><quote>+handle-as-image</quote></link>
8673 <link linkend="HANDLE-AS-EMPTY-DOCUMENT"><quote>+handle-as-empty-document</quote></link>
8674 are then checked, and if there is no match, an
8675 HTML <quote>BLOCKED</quote> page is sent back to the browser. Otherwise, if
8676 it does match, an image is returned for the former, and an empty text
8677 document for the latter. The type of image would depend on the setting of
8678 <link linkend="SET-IMAGE-BLOCKER"><quote>+set-image-blocker</quote></link>
8679 (blank, checkerboard pattern, or an HTTP redirect to an image elsewhere).
8684 Untrusted URLs are blocked. If URLs are being added to the
8685 <filename>trust</filename> file, then that is done.
8690 If the URL pattern matches the <link
8691 linkend="FAST-REDIRECTS"><quote>+fast-redirects</quote></link> action,
8692 it is then processed. Unwanted parts of the requested URL are stripped.
8697 Now the rest of the client browser's request headers are processed. If any
8698 of these match any of the relevant actions (e.g. <link
8699 linkend="HIDE-USER-AGENT"><quote>+hide-user-agent</quote></link>,
8700 etc.), headers are suppressed or forged as determined by these actions and
8706 Now the web server starts sending its response back (i.e. typically a web
8712 First, the server headers are read and processed to determine, among other
8713 things, the MIME type (document type) and encoding. The headers are then
8714 filtered as determined by the
8715 <link linkend="CRUNCH-INCOMING-COOKIES"><quote>+crunch-incoming-cookies</quote></link>,
8716 <link linkend="SESSION-COOKIES-ONLY"><quote>+session-cookies-only</quote></link>,
8717 and <link linkend="DOWNGRADE-HTTP-VERSION"><quote>+downgrade-http-version</quote></link>
8723 If any <link linkend="FILTER"><quote>+filter</quote></link> action
8725 linkend="DEANIMATE-GIFS"><quote>+deanimate-gifs</quote></link>
8726 action applies (and the document type fits the action), the rest of the page is
8727 read into memory (up to a configurable limit). Then the filter rules (from
8728 <filename>default.filter</filename> and any other filter files) are
8729 processed against the buffered content. Filters are applied in the order
8730 they are specified in one of the filter files. Animated GIFs, if present,
8731 are reduced to either the first or last frame, depending on the action
8732 setting.The entire page, which is now filtered, is then sent by
8733 <application>Privoxy</application> back to your browser.
8736 If neither a <link linkend="FILTER"><quote>+filter</quote></link> action
8738 linkend="DEANIMATE-GIFS"><quote>+deanimate-gifs</quote></link>
8739 matches, then <application>Privoxy</application> passes the raw data through
8740 to the client browser as it becomes available.
8745 As the browser receives the now (possibly filtered) page content, it
8746 reads and then requests any URLs that may be embedded within the page
8747 source, e.g. ad images, stylesheets, JavaScript, other HTML documents (e.g.
8748 frames), sounds, etc. For each of these objects, the browser issues a
8749 separate request (this is easily viewable in <application>Privoxy's</application>
8750 logs). And each such request is in turn processed just as above. Note that a
8751 complex web page will have many, many such embedded URLs. If these
8752 secondary requests are to a different server, then quite possibly a very
8753 differing set of actions is triggered.
8760 NOTE: This is somewhat of a simplistic overview of what happens with each URL
8761 request. For the sake of brevity and simplicity, we have focused on
8762 <application>Privoxy's</application> core features only.
8768 <!-- ~~~~~ New section ~~~~~ -->
8769 <sect2 id="actionsanat">
8770 <title>Troubleshooting: Anatomy of an Action</title>
8773 The way <application>Privoxy</application> applies
8774 <link linkend="ACTIONS">actions</link> and <link linkend="FILTER">filters</link>
8775 to any given URL can be complex, and not always so
8776 easy to understand what is happening. And sometimes we need to be able to
8777 <emphasis>see</emphasis> just what <application>Privoxy</application> is
8778 doing. Especially, if something <application>Privoxy</application> is doing
8779 is causing us a problem inadvertently. It can be a little daunting to look at
8780 the actions and filters files themselves, since they tend to be filled with
8781 <link linkend="regex">regular expressions</link> whose consequences are not
8786 One quick test to see if <application>Privoxy</application> is causing a problem
8787 or not, is to disable it temporarily. This should be the first troubleshooting
8788 step (be sure to flush caches afterward!). Looking at the
8789 logs is a good idea too. (Note that both the toggle feature and logging are
8790 enabled via <filename>config</filename> file settings, and may need to be
8791 turned <quote>on</quote>.)
8794 Another easy troubleshooting step to try is if you have done any
8795 customization of your installation, revert back to the installed
8796 defaults and see if that helps. There are times the developers get complaints
8797 about one thing or another, and the problem is more related to a customized
8798 configuration issue.
8802 <application>Privoxy</application> also provides the
8803 <ulink url="http://config.privoxy.org/show-url-info">http://config.privoxy.org/show-url-info</ulink>
8804 page that can show us very specifically how <application>actions</application>
8805 are being applied to any given URL. This is a big help for troubleshooting.
8809 First, enter one URL (or partial URL) at the prompt, and then
8810 <application>Privoxy</application> will tell us
8811 how the current configuration will handle it. This will not
8812 help with filtering effects (i.e. the <link
8813 linkend="FILTER"><quote>+filter</quote></link> action) from
8814 one of the filter files since this is handled very
8815 differently and not so easy to trap! It also will not tell you about any other
8816 URLs that may be embedded within the URL you are testing. For instance, images
8817 such as ads are expressed as URLs within the raw page source of HTML pages. So
8818 you will only get info for the actual URL that is pasted into the prompt area
8819 -- not any sub-URLs. If you want to know about embedded URLs like ads, you
8820 will have to dig those out of the HTML source. Use your browser's <quote>View
8821 Page Source</quote> option for this. Or right click on the ad, and grab the
8826 Let's try an example, <ulink url="http://google.com">google.com</ulink>,
8827 and look at it one section at a time in a sample configuration (your real
8828 configuration may vary):
8832 Matches for http://www.google.com:
8834 In file: default.action <guibutton>[ View ]</guibutton> <guibutton>[ Edit ]</guibutton>
8836 {+change-x-forwarded-for{block}
8837 +deanimate-gifs {last}
8838 +fast-redirects {check-decoded-url}
8839 +filter {refresh-tags}
8840 +filter {img-reorder}
8841 +filter {banners-by-size}
8843 +filter {jumping-windows}
8844 +filter {ie-exploits}
8845 +hide-from-header {block}
8846 +hide-referrer {forge}
8847 +session-cookies-only
8848 +set-image-blocker {pattern} }
8851 { -session-cookies-only }
8857 In file: user.action <guibutton>[ View ]</guibutton> <guibutton>[ Edit ]</guibutton>
8858 (no matches in this file)
8862 This is telling us how we have defined our
8863 <link linkend="ACTIONS"><quote>actions</quote></link>, and
8864 which ones match for our test case, <quote>google.com</quote>.
8865 Displayed is all the actions that are available to us. Remember,
8866 the <literal>+</literal> sign denotes <quote>on</quote>. <literal>-</literal>
8867 denotes <quote>off</quote>. So some are <quote>on</quote> here, but many
8868 are <quote>off</quote>. Each example we try may provide a slightly different
8869 end result, depending on our configuration directives.
8873 is for our <filename>default.action</filename> file. The large, multi-line
8874 listing, is how the actions are set to match for all URLs, i.e. our default
8875 settings. If you look at your <quote>actions</quote> file, this would be the
8876 section just below the <quote>aliases</quote> section near the top. This
8877 will apply to all URLs as signified by the single forward slash at the end
8878 of the listing -- <quote> / </quote>.
8882 But we have defined additional actions that would be exceptions to these general
8883 rules, and then we list specific URLs (or patterns) that these exceptions
8884 would apply to. Last match wins. Just below this then are two explicit
8885 matches for <quote>.google.com</quote>. The first is negating our previous
8886 cookie setting, which was for <link
8887 linkend="SESSION-COOKIES-ONLY"><quote>+session-cookies-only</quote></link>
8888 (i.e. not persistent). So we will allow persistent cookies for google, at
8889 least that is how it is in this example. The second turns
8890 <emphasis>off</emphasis> any <link
8891 linkend="FAST-REDIRECTS"><quote>+fast-redirects</quote></link>
8892 action, allowing this to take place unmolested. Note that there is a leading
8893 dot here -- <quote>.google.com</quote>. This will match any hosts and
8894 sub-domains, in the google.com domain also, such as
8895 <quote>www.google.com</quote> or <quote>mail.google.com</quote>. But it would not
8896 match <quote>www.google.de</quote>! So, apparently, we have these two actions
8897 defined as exceptions to the general rules at the top somewhere in the lower
8898 part of our <filename>default.action</filename> file, and
8899 <quote>google.com</quote> is referenced somewhere in these latter sections.
8903 Then, for our <filename>user.action</filename> file, we again have no hits.
8904 So there is nothing google-specific that we might have added to our own, local
8905 configuration. If there was, those actions would over-rule any actions from
8906 previously processed files, such as <filename>default.action</filename>.
8907 <filename>user.action</filename> typically has the last word. This is the
8908 best place to put hard and fast exceptions,
8912 And finally we pull it all together in the bottom section and summarize how
8913 <application>Privoxy</application> is applying all its <quote>actions</quote>
8914 to <quote>google.com</quote>:
8922 +change-x-forwarded-for{block}
8923 -client-header-filter{hide-tor-exit-notation}
8924 -content-type-overwrite
8925 -crunch-client-header
8926 -crunch-if-none-match
8927 -crunch-incoming-cookies
8928 -crunch-outgoing-cookies
8929 -crunch-server-header
8930 +deanimate-gifs {last}
8931 -downgrade-http-version
8934 -filter {content-cookies}
8935 -filter {all-popups}
8936 -filter {banners-by-link}
8937 -filter {tiny-textforms}
8938 -filter {frameset-borders}
8939 -filter {demoronizer}
8940 -filter {shockwave-flash}
8941 -filter {quicktime-kioskmode}
8943 -filter {crude-parental}
8944 -filter {site-specifics}
8945 -filter {js-annoyances}
8946 -filter {html-annoyances}
8947 +filter {refresh-tags}
8948 -filter {unsolicited-popups}
8949 +filter {img-reorder}
8950 +filter {banners-by-size}
8952 +filter {jumping-windows}
8953 +filter {ie-exploits}
8960 -handle-as-empty-document
8962 -hide-accept-language
8963 -hide-content-disposition
8964 +hide-from-header {block}
8965 -hide-if-modified-since
8966 +hide-referrer {forge}
8969 -overwrite-last-modified
8970 -prevent-compression
8972 -server-header-filter{xml-to-html}
8973 -server-header-filter{html-to-xml}
8974 -session-cookies-only
8975 +set-image-blocker {pattern}
8979 Notice the only difference here to the previous listing, is to
8980 <quote>fast-redirects</quote> and <quote>session-cookies-only</quote>,
8981 which are activated specifically for this site in our configuration,
8982 and thus show in the <quote>Final Results</quote>.
8986 Now another example, <quote>ad.doubleclick.net</quote>:
8990 { +block{Domains starts with "ad"} }
8993 { +block{Domain contains "ad"} }
8996 { +block{Doubleclick banner server} +handle-as-image }
8997 .[a-vx-z]*.doubleclick.net
9001 We'll just show the interesting part here - the explicit matches. It is
9002 matched three different times. Two <quote>+block{}</quote> sections,
9003 and a <quote>+block{} +handle-as-image</quote>,
9004 which is the expanded form of one of our aliases that had been defined as:
9005 <quote>+block-as-image</quote>. (<link
9006 linkend="ALIASES"><quote>Aliases</quote></link> are defined in
9007 the first section of the actions file and typically used to combine more
9012 Any one of these would have done the trick and blocked this as an unwanted
9013 image. This is unnecessarily redundant since the last case effectively
9014 would also cover the first. No point in taking chances with these guys
9015 though ;-) Note that if you want an ad or obnoxious
9016 URL to be invisible, it should be defined as <quote>ad.doubleclick.net</quote>
9017 is done here -- as both a <link
9018 linkend="BLOCK"><quote>+block{}</quote></link>
9019 <emphasis>and</emphasis> an
9020 <link linkend="HANDLE-AS-IMAGE"><quote>+handle-as-image</quote></link>.
9021 The custom alias <quote><literal>+block-as-image</literal></quote> just
9022 simplifies the process and make it more readable.
9026 One last example. Let's try <quote>http://www.example.net/adsl/HOWTO/</quote>.
9027 This one is giving us problems. We are getting a blank page. Hmmm ...
9031 Matches for http://www.example.net/adsl/HOWTO/:
9033 In file: default.action <guibutton>[ View ]</guibutton> <guibutton>[ Edit ]</guibutton>
9037 +change-x-forwarded-for{block}
9038 -client-header-filter{hide-tor-exit-notation}
9039 -content-type-overwrite
9040 -crunch-client-header
9041 -crunch-if-none-match
9042 -crunch-incoming-cookies
9043 -crunch-outgoing-cookies
9044 -crunch-server-header
9046 -downgrade-http-version
9047 +fast-redirects {check-decoded-url}
9049 -filter {content-cookies}
9050 -filter {all-popups}
9051 -filter {banners-by-link}
9052 -filter {tiny-textforms}
9053 -filter {frameset-borders}
9054 -filter {demoronizer}
9055 -filter {shockwave-flash}
9056 -filter {quicktime-kioskmode}
9058 -filter {crude-parental}
9059 -filter {site-specifics}
9060 -filter {js-annoyances}
9061 -filter {html-annoyances}
9062 +filter {refresh-tags}
9063 -filter {unsolicited-popups}
9064 +filter {img-reorder}
9065 +filter {banners-by-size}
9067 +filter {jumping-windows}
9068 +filter {ie-exploits}
9075 -handle-as-empty-document
9077 -hide-accept-language
9078 -hide-content-disposition
9079 +hide-from-header{block}
9080 +hide-referer{forge}
9082 -overwrite-last-modified
9083 +prevent-compression
9085 -server-header-filter{xml-to-html}
9086 -server-header-filter{html-to-xml}
9087 +session-cookies-only
9088 +set-image-blocker{blank} }
9091 { +block{Path contains "ads".} +handle-as-image }
9096 Ooops, the <quote>/adsl/</quote> is matching <quote>/ads</quote> in our
9097 configuration! But we did not want this at all! Now we see why we get the
9098 blank page. It is actually triggering two different actions here, and
9099 the effects are aggregated so that the URL is blocked, and &my-app; is told
9100 to treat the block as if it were an image. But this is, of course, all wrong.
9101 We could now add a new action below this (or better in our own
9102 <filename>user.action</filename> file) that explicitly
9103 <emphasis>un</emphasis> blocks (
9104 <link linkend="BLOCK"><quote>{-block}</quote></link>) paths with
9105 <quote>adsl</quote> in them (remember, last match in the configuration
9106 wins). There are various ways to handle such exceptions. Example:
9115 Now the page displays ;-)
9116 Remember to flush your browser's caches when making these kinds of changes to
9117 your configuration to insure that you get a freshly delivered page! Or, try
9118 using <literal>Shift+Reload</literal>.
9122 But now what about a situation where we get no explicit matches like
9127 { +block{Path starts with "ads".} +handle-as-image }
9132 That actually was very helpful and pointed us quickly to where the problem
9133 was. If you don't get this kind of match, then it means one of the default
9134 rules in the first section of <filename>default.action</filename> is causing
9135 the problem. This would require some guesswork, and maybe a little trial and
9136 error to isolate the offending rule. One likely cause would be one of the
9137 <link linkend="FILTER"><quote>+filter</quote></link> actions.
9138 These tend to be harder to troubleshoot.
9139 Try adding the URL for the site to one of aliases that turn off
9140 <link linkend="FILTER"><quote>+filter</quote></link>:
9146 .worldpay.com # for quietpc.com
9153 <quote><literal>{ shop }</literal></quote> is an <quote>alias</quote> that expands to
9154 <quote><literal>{ -filter -session-cookies-only }</literal></quote>.
9155 Or you could do your own exception to negate filtering:
9160 # Disable ALL filter actions for sites in this section
9167 This would turn off all filtering for these sites. This is best
9168 put in <filename>user.action</filename>, for local site
9169 exceptions. Note that when a simple domain pattern is used by itself (without
9170 the subsequent path portion), all sub-pages within that domain are included
9171 automatically in the scope of the action.
9175 Images that are inexplicably being blocked, may well be hitting the
9176 <link linkend="FILTER-BANNERS-BY-SIZE"><quote>+filter{banners-by-size}</quote></link>
9178 that images of certain sizes are ad banners (works well
9179 <emphasis>most of the time</emphasis> since these tend to be standardized).
9183 <quote><literal>{ fragile }</literal></quote> is an alias that disables most
9184 actions that are the most likely to cause trouble. This can be used as a
9185 last resort for problem sites.
9190 # Handle with care: easy to break
9197 <emphasis>Remember to flush caches!</emphasis> Note that the
9198 <literal>mail.google</literal> reference lacks the TLD portion (e.g.
9199 <quote>.com</quote>). This will effectively match any TLD with
9200 <literal>google</literal> in it, such as <literal>mail.google.de.</literal>,
9204 If this still does not work, you will have to go through the remaining
9205 actions one by one to find which one(s) is causing the problem.
9214 This program is free software; you can redistribute it
9215 and/or modify it under the terms of the GNU General
9216 Public License as published by the Free Software
9217 Foundation; either version 2 of the License, or (at
9218 your option) any later version.
9220 This program is distributed in the hope that it will
9221 be useful, but WITHOUT ANY WARRANTY; without even the
9222 implied warranty of MERCHANTABILITY or FITNESS FOR A
9223 PARTICULAR PURPOSE. See the GNU General Public
9224 License for more details.
9226 The GNU General Public License should be included with
9227 this file. If not, you can view it at
9228 http://www.gnu.org/copyleft/gpl.html
9229 or write to the Free Software Foundation, Inc.,
9230 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301,