1 <!DOCTYPE article PUBLIC "-//OASIS//DTD DocBook V3.1//EN" [
2 <!entity % dummy "IGNORE">
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">
9 <!entity history SYSTEM "history.sgml">
10 <!entity copyright SYSTEM "copyright.sgml">
11 <!entity license SYSTEM "license.sgml">
12 <!entity p-authors SYSTEM "p-authors.sgml">
13 <!entity config SYSTEM "p-config.sgml">
14 <!entity changelog SYSTEM "changelog.sgml">
15 <!entity p-version "3.0.20">
16 <!entity p-status "beta">
17 <!entity % p-authors-formal "INCLUDE"> <!-- include additional text, etc -->
18 <!entity % p-not-stable "INCLUDE">
19 <!entity % p-stable "IGNORE">
20 <!entity % p-text "IGNORE"> <!-- define we are not a text only doc -->
21 <!entity % p-doc "INCLUDE"> <!-- and we are a formal doc -->
22 <!entity % p-readme "IGNORE">
23 <!entity % user-man "IGNORE">
24 <!entity % config-file "IGNORE">
25 <!entity % p-supp-userman "IGNORE"> <!-- Omit some from supported.sgml -->
26 <!entity my-copy "©"> <!-- kludge for docbook2man -->
27 <!entity % draft "IGNORE"> <!-- WIP stuff -->
28 <!entity % seealso-extra "INCLUDE"> <!-- extra stuff from seealso.sgml -->
29 <!entity my-app "<application>Privoxy</application>">
32 File : $Source: /cvsroot/ijbswa/current/doc/source/user-manual.sgml,v $
35 This file belongs into
36 ijbswa.sourceforge.net:/home/groups/i/ij/ijbswa/htdocs/
38 $Id: user-manual.sgml,v 2.165 2013/01/20 18:10:28 fabiankeil Exp $
40 Copyright (C) 2001-2013 Privoxy Developers http://www.privoxy.org/
43 ========================================================================
44 NOTE: Please read developer-manual/documentation.html before touching
45 anything in this, or other Privoxy documentation.
46 ========================================================================
53 <title>Privoxy &p-version; User Manual</title>
57 <!-- Completely the wrong markup, but very little is allowed -->
58 <!-- in this part of an article. FIXME -->
59 <link linkend="copyright">Copyright</link> &my-copy; 2001-2013 by
60 <ulink url="http://www.privoxy.org/">Privoxy Developers</ulink>
64 <pubdate>$Id: user-manual.sgml,v 2.165 2013/01/20 18:10:28 fabiankeil Exp $</pubdate>
68 Note: the following should generate a separate page, and a live link to it,
69 all nicely done. But it doesn't for some mysterious reason. Please leave
70 commented unless it can be fixed proper. For the time being, the
71 copyright/license declarations will be in their own sgml.
84 This is here to keep vim syntax file from breaking :/
85 If I knew enough to fix it, I would.
86 PLEASE DO NOT REMOVE! HB: hal@foobox.net
92 The <citetitle>Privoxy User Manual</citetitle> gives users information on how to
93 install, configure and use <ulink
94 url="http://www.privoxy.org/">Privoxy</ulink>.
97 <!-- Include privoxy.sgml boilerplate: -->
99 <!-- end privoxy.sgml -->
102 You can find the latest version of the <citetitle>Privoxy User Manual</citetitle> at <ulink
103 url="http://www.privoxy.org/user-manual/">http://www.privoxy.org/user-manual/</ulink>.
104 Please see the <link linkend="contact">Contact section</link> on how to
105 contact the developers.
109 <!-- Feel free to send a note to the developers at <email>ijbswa-developers@lists.sourceforge.net</email>. -->
115 <!-- ~~~~~ New section ~~~~~ -->
116 <sect1 label="1" id="introduction"><title>Introduction</title>
118 This documentation is included with the current &p-status; version of
119 <application>Privoxy</application>, v.&p-version;<![%p-not-stable;[,
120 and is mostly complete at this point. The most up to date reference for the
121 time being is still the comments in the source files and in the individual
122 configuration files. Development of a new version is currently nearing
123 completion, and includes significant changes and enhancements over
127 <!-- include only in non-stable versions -->
130 Since this is a &p-status; version, not all new features are well tested. This
131 documentation may be slightly out of sync as a result (especially with
132 CVS sources). And there <emphasis>may be</emphasis> bugs, though hopefully
137 <!-- ~~~~~ New section ~~~~~ -->
138 <sect2 id="features"><title>Features</title>
140 In addition to the core
141 features of ad blocking and
142 <ulink url="http://en.wikipedia.org/wiki/Browser_cookie">cookie</ulink> management,
143 <application>Privoxy</application> provides many supplemental
144 features<![%p-not-stable;[, some of them currently under development]]>,
145 that give the end-user more control, more privacy and more freedom:
147 <!-- Include newfeatures.sgml boilerplate here: -->
149 <!-- end boilerplate -->
154 <!-- ~ End section ~ -->
157 <!-- ~~~~~ New section ~~~~~ -->
158 <sect1 id="installation"><title>Installation</title>
161 <application>Privoxy</application> is available both in convenient pre-compiled
162 packages for a wide range of operating systems, and as raw source code.
163 For most users, we recommend using the packages, which can be downloaded from our
164 <ulink url="http://sourceforge.net/projects/ijbswa/">Privoxy Project
170 On some platforms, the installer may remove previously installed versions, if
171 found. (See below for your platform). In any case <emphasis>be sure to backup
172 your old configuration if it is valuable to you.</emphasis> See the <link
173 linkend="upgradersnote">note to upgraders</link> section below.
176 <!-- ~~~~~ New section ~~~~~ -->
177 <sect2 id="installation-packages"><title>Binary Packages</title>
179 How to install the binary packages depends on your operating system:
182 <!-- XXX: The installation sections should be sorted -->
184 <!-- ~~~~~ New section ~~~~~ -->
185 <sect3 id="installation-deb"><title>Debian and Ubuntu</title>
187 DEBs can be installed with <literal>apt-get install privoxy</literal>,
188 and will use <filename>/etc/privoxy</filename> for the location of
193 <!-- ~~~~~ New section ~~~~~ -->
194 <sect3 id="installation-pack-win"><title>Windows</title>
197 Just double-click the installer, which will guide you through
198 the installation process. You will find the configuration files
199 in the same directory as you installed <application>Privoxy</application> in.
202 Version 3.0.5 beta introduced full <application>Windows</application> service
203 functionality. On Windows only, the <application>Privoxy</application>
204 program has two new command line arguments to install and uninstall
205 <application>Privoxy</application> as a <emphasis>service</emphasis>.
209 <term>Arguments:</term>
212 <replaceable class="parameter">--install</replaceable>[:<replaceable class="parameter">service_name</replaceable>]
215 <replaceable class="parameter">--uninstall</replaceable>[:<replaceable class="parameter">service_name</replaceable>]
221 After invoking <application>Privoxy</application> with
222 <command>--install</command>, you will need to bring up the
223 <application>Windows</application> service console to assign the user you
224 want <application>Privoxy</application> to run under, and whether or not you
225 want it to run whenever the system starts. You can start the
226 <application>Windows</application> services console with the following
227 command: <command>services.msc</command>. If you do not take the manual step
228 of modifying <application>Privoxy's</application> service settings, it will
229 not start. Note too that you will need to give Privoxy a user account that
230 actually exists, or it will not be permitted to
231 write to its log and configuration files.
236 <!-- ~~~~~ New section ~~~~~ -->
237 <sect3 id="installation-os2"><title>OS/2</title>
240 First, make sure that no previous installations of
241 <application>Junkbuster</application> and / or
242 <application>Privoxy</application> are left on your
243 system. Check that no <application>Junkbuster</application>
244 or <application>Privoxy</application> objects are in
250 Then, just double-click the WarpIN self-installing archive, which will
251 guide you through the installation process. A shadow of the
252 <application>Privoxy</application> executable will be placed in your
253 startup folder so it will start automatically whenever OS/2 starts.
257 The directory you choose to install <application>Privoxy</application>
258 into will contain all of the configuration files.
262 <!-- ~~~~~ New section ~~~~~ -->
263 <sect3 id="installation-mac"><title>Mac OS X</title>
265 Installation instructions for the OS X platform depend upon whether
266 you downloaded a ready-built installation package (.pkg or .mpkg) or have
267 downloaded the source code.
270 <sect3 renderas="sect4" id="OS-X-install-from-package">
271 <title>Installation from ready-built package</title>
273 The downloaded file will either be a .pkg (for OS X 10.5 upwards) or a bzipped
274 .mpkg file (for OS X 10.4). The former can be double-clicked as is and the
275 installation will start; double-clicking the latter will unzip the .mpkg file
276 which can then be double-clicked to commence the installation.
279 The privoxy service will automatically start after a successful installation
280 (and thereafter every time your computer starts up) however you will need to
281 configure your web browser(s) to use it. To do so, configure them to use a
282 proxy for HTTP and HTTPS at the address 127.0.0.1:8118.
285 To prevent the privoxy service from automatically starting when your computer
286 starts up, remove or rename the file <literal>/Library/LaunchDaemons/org.ijbswa.privoxy.plist</literal>
287 (on OS X 10.5 and higher) or the folder named
288 <literal>/Library/StartupItems/Privoxy</literal> (on OS X 10.4 'Tiger').
291 To manually start or stop the privoxy service, use the scripts startPrivoxy.sh
292 and stopPrivoxy.sh supplied in /Applications/Privoxy. They must be run from an
293 administrator account, using sudo.
296 To uninstall, run /Applications/Privoxy/uninstall.command as sudo from an
297 administrator account.
300 <sect3 renderas="sect4" id="OS-X-install-from-source">
301 <title>Installation from source</title>
303 To build and install the Privoxy source code on OS X you will need to obtain
304 the macsetup module from the Privoxy Sourceforge CVS repository (refer to
305 Sourceforge help for details of how to set up a CVS client to have read-only
306 access to the repository). This module contains scripts that leverage the usual
307 open-source tools (available as part of Apple's free of charge Xcode
308 distribution or via the usual open-source software package managers for OS X
309 (MacPorts, Homebrew, Fink etc.) to build and then install the privoxy binary
310 and associated files. The macsetup module's README file contains complete
311 instructions for its use.
314 The privoxy service will automatically start after a successful installation
315 (and thereafter every time your computer starts up) however you will need to
316 configure your web browser(s) to use it. To do so, configure them to use a
317 proxy for HTTP and HTTPS at the address 127.0.0.1:8118.
320 To prevent the privoxy service from automatically starting when your computer
321 starts up, remove or rename the file <literal>/Library/LaunchDaemons/org.ijbswa.privoxy.plist</literal>
322 (on OS X 10.5 and higher) or the folder named
323 <literal>/Library/StartupItems/Privoxy</literal> (on OS X 10.4 'Tiger').
326 To manually start or stop the privoxy service, use the Privoxy Utility
327 for Mac OS X (also part of the macsetup module). This application can start
328 and stop the privoxy service and display its log and configuration files.
331 To uninstall, run the macsetup module's uninstall.sh as sudo from an
332 administrator account.
336 <!-- ~~~~~ New section ~~~~~ -->
337 <sect3 id="installation-tbz"><title>FreeBSD</title>
340 Privoxy is part of FreeBSD's Ports Collection, you can build and install
341 it with <literal>cd /usr/ports/www/privoxy; make install clean</literal>.
344 If you don't use the ports, you can fetch and install
345 the package with <literal>pkg_add -r privoxy</literal>.
348 The port skeleton and the package can also be downloaded from the
349 <ulink url="https://sourceforge.net/project/showfiles.php?group_id=11118">File Release
350 Page</ulink>, but there's no reason to use them unless you're interested in the
351 beta releases which are only available there.
357 <!-- ~~~~~ New section ~~~~~ -->
358 <sect2 id="installation-source"><title>Building from Source</title>
361 The most convenient way to obtain the <application>Privoxy</application> sources
362 is to download the source tarball from our
363 <ulink url="http://sourceforge.net/project/showfiles.php?group_id=11118&package_id=10571">project download
368 If you like to live on the bleeding edge and are not afraid of using
369 possibly unstable development versions, you can check out the up-to-the-minute
370 version directly from <ulink url="http://sourceforge.net/cvs/?group_id=11118">the
371 CVS repository</ulink>.
373 deprecated...out of business.
374 or simply download <ulink
375 url="http://cvs.sourceforge.net/cvstarballs/ijbswa-cvsroot.tar.bz2">the nightly CVS
380 <!-- include buildsource.sgml boilerplate: -->
382 <!-- end boilerplate -->
385 <!-- ~~~~~ New section ~~~~~ -->
386 <sect2 id="installation-keepupdated"><title>Keeping your Installation Up-to-Date</title>
389 If you wish to receive an email notification whenever we release updates of
390 <application>Privoxy</application> or the actions file, <ulink
391 url="http://lists.sourceforge.net/lists/listinfo/ijbswa-announce/">subscribe
392 to our announce mailing list</ulink>, ijbswa-announce@lists.sourceforge.net.
396 In order not to lose your personal changes and adjustments when updating
397 to the latest <literal>default.action</literal> file we <emphasis>strongly
398 recommend</emphasis> that you use <literal>user.action</literal> and
399 <literal>user.filter</literal> for your local
400 customizations of <application>Privoxy</application>. See the <link
401 linkend="actions-file">Chapter on actions files</link> for details.
409 <!-- ~ End section ~ -->
411 <!-- ~~~~~ New section ~~~~~ -->
412 <sect1 id="whatsnew">
413 <title>What's New in this Release</title>
417 <!-- ~~~~~ New section ~~~~~ -->
419 <sect2 id="upgradersnote">
420 <title>Note to Upgraders</title>
423 A quick list of things to be aware of before upgrading from earlier
424 versions of <application>Privoxy</application>:
432 The recommended way to upgrade &my-app; is to backup your old
433 configuration files, install the new ones, verify that &my-app;
434 is working correctly and finally merge back your changes using
435 <application>diff</application> and maybe <application>patch</application>.
438 There are a number of new features in each &my-app; release and
439 most of them have to be explicitly enabled in the configuration
440 files. Old configuration files obviously don't do that and due
441 to syntax changes using old configuration files with a new
442 &my-app; isn't always possible anyway.
447 Note that some installers remove earlier versions completely,
448 including configuration files, therefore you should really save
449 any important configuration files!
454 On the other hand, other installers don't overwrite existing configuration
455 files, thinking you will want to do that yourself.
460 In the default configuration only fatal errors are logged now.
461 You can change that in the <link linkend="DEBUG">debug section</link>
462 of the configuration file. You may also want to enable more verbose
463 logging until you verified that the new &my-app; version is working
470 Three other config file settings are now off by default:
471 <link linkend="enable-remote-toggle">enable-remote-toggle</link>,
472 <link linkend="enable-remote-http-toggle">enable-remote-http-toggle</link>,
473 and <link linkend="enable-edit-actions">enable-edit-actions</link>.
474 If you use or want these, you will need to explicitly enable them, and
475 be aware of the security issues involved.
482 What constitutes a <quote>default</quote> configuration has changed,
483 and you may want to review which actions are <quote>on</quote> by
484 default. This is primarily a matter of emphasis, but some features
485 you may have been used to, may now be <quote>off</quote> by default.
486 There are also a number of new actions and filters you may want to
487 consider, most of which are not fully incorporated into the default
488 settings as yet (see above).
495 The default actions setting is now <literal>Cautious</literal>. Previous
496 releases had a default setting of <literal>Medium</literal>. Experienced
497 users may want to adjust this, as it is fairly conservative by &my-app;
498 standards and past practices. See <ulink
499 url="http://config.privoxy.org/edit-actions-list?f=default">
500 http://config.privoxy.org/edit-actions-list?f=default</ulink>. New users
501 should try the default settings for a while before turning up the volume.
507 The default setting has filtering turned <emphasis>off</emphasis>, which
508 subsequently means that compression is <emphasis>on</emphasis>. Remember
509 that filtering does not work on compressed pages, so if you use, or want to
510 use, filtering, you will need to force compression off. Example:
514 { +<link linkend="filter">filter</link>{google} +<link linkend="prevent-compression">prevent-compression</link> }
518 Or if you use a number of filters, or filter many sites, you may just want
519 to turn off compression for all sites in
520 <filename>default.action</filename> (or
521 <filename>user.action</filename>).
528 Also, <link linkend="SESSION-COOKIES-ONLY">session-cookies-only</link> is
529 off by default now. If you've liked this feature in the past, you may want
530 to turn it back on in <filename>user.action</filename> now.
537 Some installers may not automatically start
538 <application>Privoxy</application> after installation.
549 <!-- ~~~~~ New section ~~~~~ -->
550 <sect1 id="quickstart"><title>Quickstart to Using Privoxy</title>
556 Install <application>Privoxy</application>. See the <link
557 linkend="installation">Installation Section</link> below for platform specific
564 Advanced users and those who want to offer <application>Privoxy</application>
565 service to more than just their local machine should check the <link
566 linkend="config">main config file</link>, especially the <link
567 linkend="access-control">security-relevant</link> options. These are
574 Start <application>Privoxy</application>, if the installation program has
575 not done this already (may vary according to platform). See the section
576 <link linkend="startup">Starting <application>Privoxy</application></link>.
582 Set your browser to use <application>Privoxy</application> as HTTP and
583 HTTPS (SSL) <ulink url="http://en.wikipedia.org/wiki/Proxy_server">proxy</ulink>
584 by setting the proxy configuration for address of
585 <literal>127.0.0.1</literal> and port <literal>8118</literal>.
586 <emphasis>DO NOT</emphasis> activate proxying for <literal>FTP</literal> or
587 any protocols besides HTTP and HTTPS (SSL) unless you intend to prevent your
588 browser from using these protocols.
594 Flush your browser's disk and memory caches, to remove any cached ad images.
595 If using <application>Privoxy</application> to manage
596 <ulink url="http://en.wikipedia.org/wiki/Browser_cookie">cookies</ulink>,
597 you should remove any currently stored cookies too.
603 A default installation should provide a reasonable starting point for
604 most. There will undoubtedly be occasions where you will want to adjust the
605 configuration, but that can be dealt with as the need arises. Little
606 to no initial configuration is required in most cases, you may want
608 <ulink url="config.html#ENABLE-EDIT-ACTIONS">web-based action editor</ulink> though.
609 Be sure to read the warnings first.
612 See the <link linkend="configuration">Configuration section</link> for more
613 configuration options, and how to customize your installation.
614 You might also want to look at the <link
615 linkend="quickstart-ad-blocking">next section</link> for a quick
616 introduction to how <application>Privoxy</application> blocks ads and
623 If you experience ads that slip through, innocent images that are
624 blocked, or otherwise feel the need to fine-tune
625 <application>Privoxy's</application> behavior, take a look at the <link
626 linkend="actions-file">actions files</link>. As a quick start, you might
627 find the <link linkend="act-examples">richly commented examples</link>
628 helpful. You can also view and edit the actions files through the <ulink
629 url="http://config.privoxy.org">web-based user interface</ulink>. The
630 Appendix <quote><link linkend="actionsanat">Troubleshooting: Anatomy of an
631 Action</link></quote> has hints on how to understand and debug actions that
632 <quote>misbehave</quote>.
637 Did anyone test these lately?
641 For easy access to &my-app;'s most important controls, drag the provided
642 <link linkend="bookmarklets">Bookmarklets</link> into your browser's
650 Please see the section <link linkend="contact">Contacting the
651 Developers</link> on how to report bugs, problems with websites or to get
658 Now enjoy surfing with enhanced control, comfort and privacy!
666 <!-- ~~~~~ New section ~~~~~ -->
668 <sect2 id="quickstart-ad-blocking">
669 <title>Quickstart to Ad Blocking</title>
671 NOTE: This section is deliberately redundant for those that don't
672 want to read the whole thing (which is getting lengthy).
675 Ad blocking is but one of <application>Privoxy's</application>
676 array of features. Many of these features are for the technically minded advanced
677 user. But, ad and banner blocking is surely common ground for everybody.
680 This section will provide a quick summary of ad blocking so
681 you can get up to speed quickly without having to read the more extensive
682 information provided below, though this is highly recommended.
685 First a bit of a warning ... blocking ads is much like blocking SPAM: the
686 more aggressive you are about it, the more likely you are to block
687 things that were not intended. And the more likely that some things
688 may not work as intended. So there is a trade off here. If you want
689 extreme ad free browsing, be prepared to deal with more
690 <quote>problem</quote> sites, and to spend more time adjusting the
691 configuration to solve these unintended consequences. In short, there is
692 not an easy way to eliminate <emphasis>all</emphasis> ads. Either take
693 the easy way and settle for <emphasis>most</emphasis> ads blocked with the
694 default configuration, or jump in and tweak it for your personal surfing
695 habits and preferences.
698 Secondly, a brief explanation of <application>Privoxy's </application>
699 <quote>actions</quote>. <quote>Actions</quote> in this context, are
700 the directives we use to tell <application>Privoxy</application> to perform
701 some task relating to HTTP transactions (i.e. web browsing). We tell
702 <application>Privoxy</application> to take some <quote>action</quote>. Each
703 action has a unique name and function. While there are many potential
704 <application>actions</application> in <application>Privoxy's</application>
705 arsenal, only a few are used for ad blocking. <link
706 linkend="actions">Actions</link>, and <link linkend="actions-file">action
707 configuration files</link>, are explained in depth below.
710 Actions are specified in <application>Privoxy's</application> configuration,
711 followed by one or more URLs to which the action should apply. URLs
712 can actually be URL type <link linkend="af-patterns">patterns</link> that use
713 wildcards so they can apply potentially to a range of similar URLs. The
714 actions, together with the URL patterns are called a section.
717 When you connect to a website, the full URL will either match one or more
718 of the sections as defined in <application>Privoxy's</application> configuration,
719 or not. If so, then <application>Privoxy</application> will perform the
720 respective actions. If not, then nothing special happens. Furthermore, web
721 pages may contain embedded, secondary URLs that your web browser will
722 use to load additional components of the page, as it parses the
723 original page's HTML content. An ad image for instance, is just an URL
724 embedded in the page somewhere. The image itself may be on the same server,
725 or a server somewhere else on the Internet. Complex web pages will have many
726 such embedded URLs. &my-app; can deal with each URL individually, so, for
727 instance, the main page text is not touched, but images from such-and-such
732 The most important actions for basic ad blocking are: <literal><link
733 linkend="block">block</link></literal>, <literal><link
734 linkend="handle-as-image">handle-as-image</link></literal>,
736 linkend="handle-as-empty-document">handle-as-empty-document</link></literal>,and
737 <literal><link linkend="set-image-blocker">set-image-blocker</link></literal>:
745 <literal><link linkend="block">block</link></literal> - this is perhaps
746 the single most used action, and is particularly important for ad blocking.
747 This action stops any contact between your browser and any URL patterns
748 that match this action's configuration. It can be used for blocking ads,
749 but also anything that is determined to be unwanted. By itself, it simply
750 stops any communication with the remote server and sends
751 <application>Privoxy</application>'s own built-in BLOCKED page instead to
752 let you now what has happened (with some exceptions, see below).
758 <literal><link linkend="handle-as-image">handle-as-image</link></literal> -
759 tells <application>Privoxy</application> to treat this URL as an image.
760 <application>Privoxy</application>'s default configuration already does this
761 for all common image types (e.g. GIF), but there are many situations where this
762 is not so easy to determine. So we'll force it in these cases. This is particularly
763 important for ad blocking, since only if we know that it's an image of
764 some kind, can we replace it with an image of our choosing, instead of the
765 <application>Privoxy</application> BLOCKED page (which would only result in
766 a <quote>broken image</quote> icon). There are some limitations to this
767 though. For instance, you can't just brute-force an image substitution for
768 an entire HTML page in most situations.
774 <literal><link linkend="handle-as-empty-document">handle-as-empty-document</link></literal> -
775 sends an empty document instead of <application>Privoxy's</application>
776 normal BLOCKED HTML page. This is useful for file types that are neither
777 HTML nor images, such as blocking JavaScript files.
784 linkend="set-image-blocker">set-image-blocker</link></literal> - tells
785 <application>Privoxy</application> what to display in place of an ad image that
786 has hit a block rule. For this to come into play, the URL must match a
787 <literal><link linkend="block">block</link></literal> action somewhere in the
788 configuration, <emphasis>and</emphasis>, it must also match an
789 <literal><link linkend="handle-as-image">handle-as-image</link></literal> action.
792 The configuration options on what to display instead of the ad are:
796 <emphasis>pattern</emphasis> - a checkerboard pattern, so that an ad
797 replacement is obvious. This is the default.
802 <emphasis>blank</emphasis> - A very small empty GIF image is displayed.
803 This is the so-called <quote>invisible</quote> configuration option.
808 <emphasis>http://<URL></emphasis> - A redirect to any image anywhere
809 of the user's choosing (advanced usage).
818 Advanced users will eventually want to explore &my-app;
819 <literal><link linkend="filter">filters</link></literal> as well. Filters
820 are very different from <literal><link
821 linkend="block">blocks</link></literal>.
822 A <quote>block</quote> blocks a site, page, or unwanted contented. Filters
823 are a way of filtering or modifying what is actually on the page. An example
824 filter usage: a text replacement of <quote>no-no</quote> for
825 <quote>nasty-word</quote>. That is a very simple example. This process can be
826 used for ad blocking, but it is more in the realm of advanced usage and has
827 some pitfalls to be wary off.
831 The quickest way to adjust any of these settings is with your browser through
832 the special <application>Privoxy</application> editor at <ulink
833 url="http://config.privoxy.org/show-status">http://config.privoxy.org/show-status</ulink>
834 (shortcut: <ulink url="http://p.p/">http://p.p/show-status</ulink>). This
835 is an internal page, and does not require Internet access.
839 Note that as of <application>Privoxy</application> 3.0.7 beta the
840 action editor is disabled by default. Check the
841 <ulink url="config.html#ENABLE-EDIT-ACTIONS">enable-edit-actions
842 section in the configuration file</ulink> to learn why and in which
843 cases it's safe to enable again.
847 If you decided to enable the action editor, select the appropriate
848 <quote>actions</quote> file, and click
849 <quote><guibutton>Edit</guibutton></quote>. It is best to put personal or
850 local preferences in <filename>user.action</filename> since this is not
851 meant to be overwritten during upgrades, and will over-ride the settings in
852 other files. Here you can insert new <quote>actions</quote>, and URLs for ad
853 blocking or other purposes, and make other adjustments to the configuration.
854 <application>Privoxy</application> will detect these changes automatically.
858 A quick and simple step by step example:
866 Right click on the ad image to be blocked, then select
867 <quote><guimenuitem>Copy Link Location</guimenuitem></quote> from the
875 url="http://config.privoxy.org/show-status">http://config.privoxy.org/show-status</ulink>
880 Find <filename>user.action</filename> in the top section, and click
881 on <quote><guibutton>Edit</guibutton></quote>:
884 <!-- image of editor and actions files selections -->
886 <figure pgwide="0" float="0"><title>Actions Files in Use</title>
889 <imagedata fileref="files-in-use.jpg" format="jpg">
892 <phrase>[ Screenshot of Actions Files in Use ]</phrase>
901 You should have a section with only
902 <literal><link linkend="block">block</link></literal> listed under
903 <quote>Actions:</quote>.
904 If not, click a <quote><guibutton>Insert new section below</guibutton></quote>
905 button, and in the new section that just appeared, click the
906 <guibutton>Edit</guibutton> button right under the word <quote>Actions:</quote>.
907 This will bring up a list of all actions. Find
908 <literal><link linkend="block">block</link></literal> near the top, and click
909 in the <quote>Enabled</quote> column, then <quote><guibutton>Submit</guibutton></quote>
915 Now, in the <literal><link linkend="block">block</link></literal> actions section,
916 click the <quote><guibutton>Add</guibutton></quote> button, and paste the URL the
917 browser got from <quote><guimenuitem>Copy Link Location</guimenuitem></quote>.
918 Remove the <literal>http://</literal> at the beginning of the URL. Then, click
919 <quote><guibutton>Submit</guibutton></quote> (or
920 <quote><guibutton>OK</guibutton></quote> if in a pop-up window).
925 Now go back to the original page, and press <keycap>SHIFT-Reload</keycap>
926 (or flush all browser caches). The image should be gone now.
934 This is a very crude and simple example. There might be good reasons to use a
935 wildcard pattern match to include potentially similar images from the same
936 site. For a more extensive explanation of <quote>patterns</quote>, and
937 the entire actions concept, see <link linkend="actions-file">the Actions
942 For advanced users who want to hand edit their config files, you might want
943 to now go to the <link linkend="act-examples">Actions Files Tutorial</link>.
944 The ideas explained therein also apply to the web-based editor.
947 There are also various
948 <link linkend="filter">filters</link> that can be used for ad blocking
949 (filters are a special subset of actions). These
950 fall into the <quote>advanced</quote> usage category, and are explained in
951 depth in later sections.
958 <!-- ~ End section ~ -->
961 <!-- ~~~~~ New section ~~~~~ -->
963 <title>Starting Privoxy</title>
965 Before launching <application>Privoxy</application> for the first time, you
966 will want to configure your browser(s) to use
967 <application>Privoxy</application> as a HTTP and HTTPS (SSL)
968 <ulink url="http://en.wikipedia.org/wiki/Proxy_server">proxy</ulink>. The default is
969 127.0.0.1 (or localhost) for the proxy address, and port 8118 (earlier versions
970 used port 8000). This is the one configuration step <emphasis>that must be done
974 Please note that <application>Privoxy</application> can only proxy HTTP and
975 HTTPS traffic. It will not work with FTP or other protocols.
978 <!-- image of Mozilla Proxy configuration -->
980 <figure pgwide="0" float="0"><title>Proxy Configuration Showing
981 Mozilla/Netscape HTTP and HTTPS (SSL) Settings</title>
984 <imagedata fileref="proxy_setup.jpg" format="jpg">
987 <phrase>[ Screenshot of Mozilla Proxy Configuration ]</phrase>
995 With <application>Firefox</application>, this is typically set under:
999 <guibutton>Tools</guibutton> -> <guibutton>Options</guibutton> -> <guibutton>Advanced</guibutton> -> <guibutton>Network</guibutton> -><guibutton>Connection</guibutton> -> <guibutton>Settings</guibutton>
1004 Or optionally on some platforms:
1008 <guibutton>Edit</guibutton> -> <guibutton>Preferences</guibutton> -> <guibutton>General</guibutton> -> <guibutton>Connection Settings</guibutton> -> <guibutton>Manual Proxy Configuration</guibutton>
1014 With <application>Netscape</application> (and
1015 <application>Mozilla</application>), this can be set under:
1020 <!-- Mix ascii and gui art, something for everybody -->
1021 <!-- spacing on this is tricky -->
1022 <guibutton>Edit</guibutton> -> <guibutton>Preferences</guibutton> -> <guibutton>Advanced</guibutton> -> <guibutton>Proxies</guibutton> -> <guibutton>HTTP Proxy</guibutton>
1027 For <application>Internet Explorer v.5-7</application>:
1031 <guibutton>Tools</guibutton> -> <guibutton>Internet Options</guibutton> -> <guibutton>Connections</guibutton> -> <guibutton>LAN Settings</guibutton>
1035 Then, check <quote>Use Proxy</quote> and fill in the appropriate info
1036 (Address: 127.0.0.1, Port: 8118). Include HTTPS (SSL), if you want HTTPS
1037 proxy support too (sometimes labeled <quote>Secure</quote>). Make sure any
1038 checkboxes like <quote>Use the same proxy server for all protocols</quote> is
1039 <emphasis>UNCHECKED</emphasis>. You want only HTTP and HTTPS (SSL)!
1042 <!-- image of IE Proxy configuration -->
1044 <figure pgwide="0" float="0"><title>Proxy Configuration Showing
1045 Internet Explorer HTTP and HTTPS (Secure) Settings</title>
1048 <imagedata fileref="proxy2.jpg" format="jpg">
1051 <phrase>[ Screenshot of IE Proxy Configuration ]</phrase>
1059 After doing this, flush your browser's disk and memory caches to force a
1060 re-reading of all pages and to get rid of any ads that may be cached. Remove
1061 any <ulink url="http://en.wikipedia.org/wiki/Browser_cookie">cookies</ulink>,
1062 if you want <application>Privoxy</application> to manage that. You are now
1063 ready to start enjoying the benefits of using
1064 <application>Privoxy</application>!
1068 <application>Privoxy</application> itself is typically started by specifying the
1069 main configuration file to be used on the command line. If no configuration
1070 file is specified on the command line, <application>Privoxy</application>
1071 will look for a file named <filename>config</filename> in the current
1072 directory. Except on Win32 where it will try <filename>config.txt</filename>.
1075 <sect2 id="start-redhat">
1076 <title>Red Hat and Fedora</title>
1078 A default Red Hat installation may not start &my-app; upon boot. It will use
1079 the file <filename>/etc/privoxy/config</filename> as its main configuration
1084 # /etc/rc.d/init.d/privoxy start
1092 # service privoxy start
1097 <sect2 id="start-debian">
1098 <title>Debian</title>
1100 We use a script. Note that Debian typically starts &my-app; upon booting per
1101 default. It will use the file
1102 <filename>/etc/privoxy/config</filename> as its main configuration
1107 # /etc/init.d/privoxy start
1112 <sect2 id="start-windows">
1113 <title>Windows</title>
1115 Click on the &my-app; Icon to start <application>Privoxy</application>. If no configuration file is
1116 specified on the command line, <application>Privoxy</application> will look
1117 for a file named <filename>config.txt</filename>. Note that Windows will
1118 automatically start &my-app; when the system starts if you chose that option
1122 <application>Privoxy</application> can run with full Windows service functionality.
1123 On Windows only, the &my-app; program has two new command line arguments
1124 to install and uninstall &my-app; as a service. See the
1125 <link linkend="installation-pack-win">Windows Installation
1126 instructions</link> for details.
1130 <sect2 id="start-unices">
1131 <title>Solaris, NetBSD, FreeBSD, HP-UX and others</title>
1133 Example Unix startup command:
1137 # /usr/sbin/privoxy /etc/privoxy/config
1142 <sect2 id="start-os2">
1145 During installation, <application>Privoxy</application> is configured to
1146 start automatically when the system restarts. You can start it manually by
1147 double-clicking on the <application>Privoxy</application> icon in the
1148 <application>Privoxy</application> folder.
1152 <sect2 id="start-macosx">
1153 <title>Mac OS X</title>
1155 After downloading the privoxy software, unzip the downloaded file by
1156 double-clicking on the zip file icon. Then, double-click on the
1157 installer package icon and follow the installation process.
1160 The privoxy service will automatically start after a successful
1161 installation. In addition, the privoxy service will automatically
1162 start every time your computer starts up.
1165 To prevent the privoxy service from automatically starting when your
1166 computer starts up, remove or rename the folder named
1167 /Library/StartupItems/Privoxy.
1170 A simple application named Privoxy Utility has been created which
1171 enables administrators to easily start and stop the privoxy service.
1174 In addition, the Privoxy Utility presents a simple way for
1175 administrators to edit the various privoxy config files. A method
1176 to uninstall the software is also available.
1179 An administrator username and password must be supplied in order for
1180 the Privoxy Utility to perform any of the tasks.
1185 <sect2 id="start-amigaos">
1186 <title>AmigaOS</title>
1188 Start <application>Privoxy</application> (with RUN <>NIL:) in your
1189 <filename>startnet</filename> script (AmiTCP), in
1190 <filename>s:user-startup</filename> (RoadShow), as startup program in your
1191 startup script (Genesis), or as startup action (Miami and MiamiDx).
1192 <application>Privoxy</application> will automatically quit when you quit your
1193 TCP/IP stack (just ignore the harmless warning your TCP/IP stack may display that
1194 <application>Privoxy</application> is still running).
1198 <sect2 id="start-gentoo">
1199 <title>Gentoo</title>
1201 A script is again used. It will use the file <filename>/etc/privoxy/config
1202 </filename> as its main configuration file.
1206 /etc/init.d/privoxy start
1210 Note that <application>Privoxy</application> is not automatically started at
1211 boot time by default. You can change this with the <literal>rc-update</literal>
1216 rc-update add privoxy default
1224 See the section <link linkend="cmdoptions">Command line options</link> for
1228 must find a better place for this paragraph
1231 The included default configuration files should give a reasonable starting
1232 point. Most of the per site configuration is done in the
1233 <ulink url="actions-file.html"><quote>actions</quote></ulink> files. These are
1234 where various cookie actions are defined, ad and banner blocking, and other
1235 aspects of <application>Privoxy</application> configuration. There are several
1236 such files included, with varying levels of aggressiveness.
1240 You will probably want to keep an eye out for sites for which you may prefer
1241 persistent cookies, and add these to your actions configuration as needed. By
1242 default, most of these will be accepted only during the current browser
1243 session (aka <quote>session cookies</quote>), unless you add them to the
1244 configuration. If you want the browser to handle this instead, you will need
1245 to edit <filename>user.action</filename> (or through the web based interface)
1246 and disable this feature. If you use more than one browser, it would make
1247 more sense to let <application>Privoxy</application> handle this. In which
1248 case, the browser(s) should be set to accept all cookies.
1252 Another feature where you will probably want to define exceptions for trusted
1253 sites is the popup-killing (through <ulink
1254 url="actions-file.html#FILTER-POPUPS"><quote>+filter{popups}</quote></ulink>),
1255 because your favorite shopping, banking, or leisure site may need
1256 popups (explained below).
1260 <application>Privoxy</application> does not support all of the optional HTTP/1.1
1261 features yet. In the unlikely event that you experience inexplicable problems
1262 with browsers that use HTTP/1.1 per default
1263 (like <application>Mozilla</application> or recent versions of I.E.), you might
1264 try to force HTTP/1.0 compatibility. For Mozilla, look under <literal>Edit ->
1265 Preferences -> Debug -> Networking</literal>.
1266 Alternatively, set the <quote>+downgrade-http-version</quote> config option in
1267 <filename>default.action</filename> which will downgrade your browser's HTTP
1268 requests from HTTP/1.1 to HTTP/1.0 before processing them.
1272 After running <application>Privoxy</application> for a while, you can
1273 start to fine tune the configuration to suit your personal, or site,
1274 preferences and requirements. There are many, many aspects that can
1275 be customized. <quote>Actions</quote>
1276 can be adjusted by pointing your browser to
1277 <ulink url="http://config.privoxy.org/">http://config.privoxy.org/</ulink>
1278 (shortcut: <ulink url="http://p.p/">http://p.p/</ulink>),
1279 and then follow the link to <quote>View & Change the Current Configuration</quote>.
1280 (This is an internal page and does not require Internet access.)
1284 In fact, various aspects of <application>Privoxy</application>
1285 configuration can be viewed from this page, including
1286 current configuration parameters, source code version numbers,
1287 the browser's request headers, and <quote>actions</quote> that apply
1288 to a given URL. In addition to the actions file
1289 editor mentioned above, <application>Privoxy</application> can also
1290 be turned <quote>on</quote> and <quote>off</quote> (toggled) from this page.
1294 If you encounter problems, try loading the page without
1295 <application>Privoxy</application>. If that helps, enter the URL where
1296 you have the problems into <ulink url="http://p.p/show-url-info">the browser
1297 based rule tracing utility</ulink>. See which rules apply and why, and
1298 then try turning them off for that site one after the other, until the problem
1299 is gone. When you have found the culprit, you might want to turn the rest on
1304 If the above paragraph sounds gibberish to you, you might want to <link
1305 linkend="actions-file">read more about the actions concept</link>
1306 or even dive deep into the <link linkend="actionsanat">Appendix
1311 If you can't get rid of the problem at all, think you've found a bug in
1312 Privoxy, want to propose a new feature or smarter rules, please see the
1313 section <link linkend="contact"><quote>Contacting the
1314 Developers</quote></link> below.
1319 <!-- ~~~~~ New section ~~~~~ -->
1320 <sect2 id="cmdoptions">
1321 <title>Command Line Options</title>
1323 <application>Privoxy</application> may be invoked with the following
1324 command-line options:
1332 <emphasis>--config-test</emphasis>
1335 Exit after loading the configuration files before binding to
1336 the listen address. The exit code signals whether or not the
1337 configuration files have been successfully loaded.
1340 If the exit code is 1, at least one of the configuration files
1341 is invalid, if it is 0, all the configuration files have been
1342 successfully loaded (but may still contain errors that can
1343 currently only be detected at run time).
1346 This option doesn't affect the log setting, combination with
1347 <emphasis>--no-daemon</emphasis> is recommended if a configured
1348 log file shouldn't be used.
1353 <emphasis>--version</emphasis>
1356 Print version info and exit. Unix only.
1361 <emphasis>--help</emphasis>
1364 Print short usage info and exit. Unix only.
1369 <emphasis>--no-daemon</emphasis>
1372 Don't become a daemon, i.e. don't fork and become process group
1373 leader, and don't detach from controlling tty. Unix only.
1378 <emphasis>--pidfile FILE</emphasis>
1381 On startup, write the process ID to <emphasis>FILE</emphasis>. Delete the
1382 <emphasis>FILE</emphasis> on exit. Failure to create or delete the
1383 <emphasis>FILE</emphasis> is non-fatal. If no <emphasis>FILE</emphasis>
1384 option is given, no PID file will be used. Unix only.
1389 <emphasis>--user USER[.GROUP]</emphasis>
1392 After (optionally) writing the PID file, assume the user ID of
1393 <emphasis>USER</emphasis>, and if included the GID of GROUP. Exit if the
1394 privileges are not sufficient to do so. Unix only.
1399 <emphasis>--chroot</emphasis>
1402 Before changing to the user ID given in the <emphasis>--user</emphasis> option,
1403 chroot to that user's home directory, i.e. make the kernel pretend to the &my-app;
1404 process that the directory tree starts there. If set up carefully, this can limit
1405 the impact of possible vulnerabilities in &my-app; to the files contained in that hierarchy.
1411 <emphasis>--pre-chroot-nslookup hostname</emphasis>
1414 Specifies a hostname to look up before doing a chroot. On some systems, initializing the
1415 resolver library involves reading config files from /etc and/or loading additional shared
1416 libraries from /lib. On these systems, doing a hostname lookup before the chroot reduces
1417 the number of files that must be copied into the chroot tree.
1420 For fastest startup speed, a good value is a hostname that is not in /etc/hosts but that
1421 your local name server (listed in /etc/resolv.conf) can resolve without recursion
1422 (that is, without having to ask any other name servers). The hostname need not exist,
1423 but if it doesn't, an error message (which can be ignored) will be output.
1429 <emphasis>configfile</emphasis>
1432 If no <emphasis>configfile</emphasis> is included on the command line,
1433 <application>Privoxy</application> will look for a file named
1434 <quote>config</quote> in the current directory (except on Win32
1435 where it will look for <quote>config.txt</quote> instead). Specify
1436 full path to avoid confusion. If no config file is found,
1437 <application>Privoxy</application> will fail to start.
1445 On <application>MS Windows</application> only there are two additional
1446 command-line options to allow <application>Privoxy</application> to install and
1447 run as a <emphasis>service</emphasis>. See the
1448 <link linkend="installation-pack-win">Window Installation section</link>
1456 <!-- ~ End section ~ -->
1459 <!-- ~~~~~ New section ~~~~~ -->
1460 <sect1 id="configuration"><title>Privoxy Configuration</title>
1462 All <application>Privoxy</application> configuration is stored
1463 in text files. These files can be edited with a text editor.
1464 Many important aspects of <application>Privoxy</application> can
1465 also be controlled easily with a web browser.
1469 <!-- ~~~~~ New section ~~~~~ -->
1472 <title>Controlling Privoxy with Your Web Browser</title>
1474 <application>Privoxy</application>'s user interface can be reached through the special
1475 URL <ulink url="http://config.privoxy.org/">http://config.privoxy.org/</ulink>
1476 (shortcut: <ulink url="http://p.p/">http://p.p/</ulink>),
1477 which is a built-in page and works without Internet access.
1478 You will see the following section:
1482 <!-- Needs to be put in a table and colorized -->
1485 <bridgehead renderas="sect2"> Privoxy Menu</bridgehead>
1489 ▪ <ulink url="http://config.privoxy.org/show-status">View & change the current configuration</ulink>
1492 ▪ <ulink url="http://config.privoxy.org/show-version">View the source code version numbers</ulink>
1495 ▪ <ulink url="http://config.privoxy.org/show-request">View the request headers.</ulink>
1498 ▪ <ulink url="http://config.privoxy.org/show-url-info">Look up which actions apply to a URL and why</ulink>
1501 ▪ <ulink url="http://config.privoxy.org/toggle">Toggle Privoxy on or off</ulink>
1504 ▪ <ulink
1505 url="http://www.privoxy.org/&p-version;/user-manual/">Documentation</ulink>
1513 This should be self-explanatory. Note the first item leads to an editor for the
1514 <link linkend="actions-file">actions files</link>, which is where the ad, banner,
1515 cookie, and URL blocking magic is configured as well as other advanced features of
1516 <application>Privoxy</application>. This is an easy way to adjust various
1517 aspects of <application>Privoxy</application> configuration. The actions
1518 file, and other configuration files, are explained in detail below.
1522 <quote>Toggle Privoxy On or Off</quote> is handy for sites that might
1523 have problems with your current actions and filters. You can in fact use
1524 it as a test to see whether it is <application>Privoxy</application>
1525 causing the problem or not. <application>Privoxy</application> continues
1526 to run as a proxy in this case, but all manipulation is disabled, i.e.
1527 <application>Privoxy</application> acts like a normal forwarding proxy. There
1528 is even a toggle <link linkend="bookmarklets">Bookmarklet</link> offered, so
1529 that you can toggle <application>Privoxy</application> with one click from
1534 Note that several of the features described above are disabled by default
1535 in <application>Privoxy</application> 3.0.7 beta and later.
1537 <ulink url="config.html">configuration file</ulink> to learn why
1538 and in which cases it's safe to enable them again.
1543 <!-- ~ End section ~ -->
1548 <!-- ~~~~~ New section ~~~~~ -->
1550 <sect2 id="confoverview">
1551 <title>Configuration Files Overview</title>
1553 For Unix, *BSD and Linux, all configuration files are located in
1554 <filename>/etc/privoxy/</filename> by default. For MS Windows, OS/2, and
1555 AmigaOS these are all in the same directory as the
1556 <application>Privoxy</application> executable. <![%p-not-stable;[ The name
1557 and number of configuration files has changed from previous versions, and is
1558 subject to change as development progresses.]]>
1562 The installed defaults provide a reasonable starting point, though
1563 some settings may be aggressive by some standards. For the time being, the
1564 principle configuration files are:
1572 The <link linkend="config">main configuration file</link> is named <filename>config</filename>
1573 on Linux, Unix, BSD, OS/2, and AmigaOS and <filename>config.txt</filename>
1574 on Windows. This is a required file.
1580 <filename>match-all.action</filename> is used to define which <quote>actions</quote>
1581 relating to banner-blocking, images, pop-ups, content modification, cookie handling
1582 etc should be applied by default. It should be the first actions file loaded.
1585 <filename>default.action</filename> defines many exceptions (both positive and negative)
1586 from the default set of actions that's configured in <filename>match-all.action</filename>.
1587 It should be the second actions file loaded and shouldn't be edited by the user.
1590 Multiple actions files may be defined in <filename>config</filename>. These
1591 are processed in the order they are defined. Local customizations and locally
1592 preferred exceptions to the default policies as defined in
1593 <filename>match-all.action</filename> (which you will most probably want
1594 to define sooner or later) are best applied in <filename>user.action</filename>,
1595 where you can preserve them across upgrades. The file isn't installed by all
1596 installers, but you can easily create it yourself with a text editor.
1599 There is also a web based editor that can be accessed from
1601 url="http://config.privoxy.org/show-status">http://config.privoxy.org/show-status</ulink>
1603 url="http://p.p/show-status">http://p.p/show-status</ulink>) for the
1604 various actions files.
1610 <quote>Filter files</quote> (the <link linkend="filter-file">filter
1611 file</link>) can be used to re-write the raw page content, including
1612 viewable text as well as embedded HTML and JavaScript, and whatever else
1613 lurks on any given web page. The filtering jobs are only pre-defined here;
1614 whether to apply them or not is up to the actions files.
1615 <filename>default.filter</filename> includes various filters made
1616 available for use by the developers. Some are much more intrusive than
1617 others, and all should be used with caution. You may define additional
1618 filter files in <filename>config</filename> as you can with
1619 actions files. We suggest <filename>user.filter</filename> for any
1620 locally defined filters or customizations.
1628 The syntax of the configuration and filter files may change between different
1629 Privoxy versions, unfortunately some enhancements cost backwards compatibility.
1630 <!-- Add link to documentation-->
1634 All files use the <quote><literal>#</literal></quote> character to denote a
1635 comment (the rest of the line will be ignored) and understand line continuation
1636 through placing a backslash ("<literal>\</literal>") as the very last character
1637 in a line. If the <literal>#</literal> is preceded by a backslash, it looses
1638 its special function. Placing a <literal>#</literal> in front of an otherwise
1639 valid configuration line to prevent it from being interpreted is called "commenting
1640 out" that line. Blank lines are ignored.
1644 The actions files and filter files
1645 can use Perl style <link linkend="regex">regular expressions</link> for
1646 maximum flexibility.
1650 After making any changes, there is no need to restart
1651 <application>Privoxy</application> in order for the changes to take
1652 effect. <application>Privoxy</application> detects such changes
1653 automatically. Note, however, that it may take one or two additional
1654 requests for the change to take effect. When changing the listening address
1655 of <application>Privoxy</application>, these <quote>wake up</quote> requests
1656 must obviously be sent to the <emphasis>old</emphasis> listening address.
1661 While under development, the configuration content is subject to change.
1662 The below documentation may not be accurate by the time you read this.
1663 Also, what constitutes a <quote>default</quote> setting, may change, so
1664 please check all your configuration files on important issues.
1670 <!-- ~ End section ~ -->
1673 <!-- ~~~~~~~~ New section Header ~~~~~~~~~ -->
1675 <!-- **************************************************** -->
1676 <!-- Include config.sgml here -->
1677 <!-- This is where the entire config file is detailed. -->
1679 <!-- end include -->
1682 <!-- ~ End section ~ -->
1686 <!-- ~~~~~~~~ New section Header ~~~~~~~~~ -->
1688 <sect1 id="actions-file"><title>Actions Files</title>
1692 XXX: similar descriptions are in the Configuration Files sections.
1693 We should only describe them at one place.
1696 The actions files are used to define what <emphasis>actions</emphasis>
1697 <application>Privoxy</application> takes for which URLs, and thus determines
1698 how ad images, cookies and various other aspects of HTTP content and
1699 transactions are handled, and on which sites (or even parts thereof).
1700 There are a number of such actions, with a wide range of functionality.
1701 Each action does something a little different.
1702 These actions give us a veritable arsenal of tools with which to exert
1703 our control, preferences and independence. Actions can be combined so that
1704 their effects are aggregated when applied against a given set of URLs.
1708 are three action files included with <application>Privoxy</application> with
1715 <filename>match-all.action</filename> - is used to define which
1716 <quote>actions</quote> relating to banner-blocking, images, pop-ups,
1717 content modification, cookie handling etc should be applied by default.
1718 It should be the first actions file loaded
1723 <filename>default.action</filename> - defines many exceptions (both
1724 positive and negative) from the default set of actions that's configured
1725 in <filename>match-all.action</filename>. It is a set of rules that should
1726 work reasonably well as-is for most users. This file is only supposed to
1727 be edited by the developers. It should be the second actions file loaded.
1732 <filename>user.action</filename> - is intended to be for local site
1733 preferences and exceptions. As an example, if your ISP or your bank
1734 has specific requirements, and need special handling, this kind of
1735 thing should go here. This file will not be upgraded.
1740 <guibutton>Edit</guibutton> <guibutton>Set to Cautious</guibutton> <guibutton>Set to Medium</guibutton> <guibutton>Set to Advanced</guibutton>
1743 These have increasing levels of aggressiveness <emphasis>and have no
1744 influence on your browsing unless you select them explicitly in the
1745 editor</emphasis>. A default installation should be pre-set to
1746 <literal>Cautious</literal>. New users should try this for a while before
1747 adjusting the settings to more aggressive levels. The more aggressive
1748 the settings, then the more likelihood there is of problems such as sites
1749 not working as they should.
1752 The <guibutton>Edit</guibutton> button allows you to turn each
1753 action on/off individually for fine-tuning. The <guibutton>Cautious</guibutton>
1754 button changes the actions list to low/safe settings which will activate
1755 ad blocking and a minimal set of &my-app;'s features, and subsequently
1756 there will be less of a chance for accidental problems. The
1757 <guibutton>Medium</guibutton> button sets the list to a medium level of
1758 other features and a low level set of privacy features. The
1759 <guibutton>Advanced</guibutton> button sets the list to a high level of
1760 ad blocking and medium level of privacy. See the chart below. The latter
1761 three buttons over-ride any changes via with the
1762 <guibutton>Edit</guibutton> button. More fine-tuning can be done in the
1763 lower sections of this internal page.
1766 While the actions file editor allows to enable these settings in all
1767 actions files, they are only supposed to be enabled in the first one
1768 to make sure you don't unintentionally overrule earlier rules.
1771 The default profiles, and their associated actions, as pre-defined in
1772 <filename>default.action</filename> are:
1775 <table frame=all><title>Default Configurations</title>
1776 <tgroup cols=4 align=left colsep=1 rowsep=1>
1777 <colspec colname=c1>
1778 <colspec colname=c2>
1779 <colspec colname=c3>
1780 <colspec colname=c4>
1783 <entry>Feature</entry>
1784 <entry>Cautious</entry>
1785 <entry>Medium</entry>
1786 <entry>Advanced</entry>
1791 <!-- <entry>f1</entry> -->
1792 <!-- <entry>f2</entry> -->
1793 <!-- <entry>f3</entry> -->
1794 <!-- <entry>f4</entry> -->
1800 <entry>Ad-blocking Aggressiveness</entry>
1801 <entry>medium</entry>
1807 <entry>Ad-filtering by size</entry>
1814 <entry>Ad-filtering by link</entry>
1820 <entry>Pop-up killing</entry>
1821 <entry>blocks only</entry>
1822 <entry>blocks only</entry>
1823 <entry>blocks only</entry>
1827 <entry>Privacy Features</entry>
1829 <entry>medium</entry>
1830 <entry>medium/high</entry>
1834 <entry>Cookie handling</entry>
1836 <entry>session-only</entry>
1841 <entry>Referer forging</entry>
1848 <entry>GIF de-animation</entry>
1855 <entry>Fast redirects</entry>
1862 <entry>HTML taming</entry>
1869 <entry>JavaScript taming</entry>
1876 <entry>Web-bug killing</entry>
1883 <entry>Image tag reordering</entry>
1899 The list of actions files to be used are defined in the main configuration
1900 file, and are processed in the order they are defined (e.g.
1901 <filename>default.action</filename> is typically processed before
1902 <filename>user.action</filename>). The content of these can all be viewed and
1904 url="http://config.privoxy.org/show-status">http://config.privoxy.org/show-status</ulink>.
1905 The over-riding principle when applying actions, is that the last action that
1906 matches a given URL wins. The broadest, most general rules go first
1907 (defined in <filename>default.action</filename>),
1908 followed by any exceptions (typically also in
1909 <filename>default.action</filename>), which are then followed lastly by any
1910 local preferences (typically in <emphasis>user</emphasis><filename>.action</filename>).
1911 Generally, <filename>user.action</filename> has the last word.
1915 An actions file typically has multiple sections. If you want to use
1916 <quote>aliases</quote> in an actions file, you have to place the (optional)
1917 <link linkend="aliases">alias section</link> at the top of that file.
1918 Then comes the default set of rules which will apply universally to all
1919 sites and pages (be <emphasis>very careful</emphasis> with using such a
1920 universal set in <filename>user.action</filename> or any other actions file after
1921 <filename>default.action</filename>, because it will override the result
1922 from consulting any previous file). And then below that,
1923 exceptions to the defined universal policies. You can regard
1924 <filename>user.action</filename> as an appendix to <filename>default.action</filename>,
1925 with the advantage that it is a separate file, which makes preserving your
1926 personal settings across <application>Privoxy</application> upgrades easier.
1930 Actions can be used to block anything you want, including ads, banners, or
1931 just some obnoxious URL whose content you would rather not see. Cookies can be accepted
1932 or rejected, or accepted only during the current browser session (i.e. not
1933 written to disk), content can be modified, some JavaScripts tamed, user-tracking
1934 fooled, and much more. See below for a <link linkend="actions">complete list
1938 <!-- ~~~~~ New section ~~~~~ -->
1940 <title>Finding the Right Mix</title>
1942 Note that some <link linkend="actions">actions</link>, like cookie suppression
1943 or script disabling, may render some sites unusable that rely on these
1944 techniques to work properly. Finding the right mix of actions is not always easy and
1945 certainly a matter of personal taste. And, things can always change, requiring
1946 refinements in the configuration. In general, it can be said that the more
1947 <quote>aggressive</quote> your default settings (in the top section of the
1948 actions file) are, the more exceptions for <quote>trusted</quote> sites you
1949 will have to make later. If, for example, you want to crunch all cookies per
1950 default, you'll have to make exceptions from that rule for sites that you
1951 regularly use and that require cookies for actually useful purposes, like maybe
1952 your bank, favorite shop, or newspaper.
1956 We have tried to provide you with reasonable rules to start from in the
1957 distribution actions files. But there is no general rule of thumb on these
1958 things. There just are too many variables, and sites are constantly changing.
1959 Sooner or later you will want to change the rules (and read this chapter again :).
1963 <!-- ~~~~~ New section ~~~~~ -->
1965 <title>How to Edit</title>
1967 The easiest way to edit the actions files is with a browser by
1968 using our browser-based editor, which can be reached from <ulink
1969 url="http://config.privoxy.org/show-status">http://config.privoxy.org/show-status</ulink>.
1970 Note: the config file option <link
1971 linkend="enable-edit-actions">enable-edit-actions</link> must be enabled for
1972 this to work. The editor allows both fine-grained control over every single
1973 feature on a per-URL basis, and easy choosing from wholesale sets of defaults
1974 like <quote>Cautious</quote>, <quote>Medium</quote> or
1975 <quote>Advanced</quote>. Warning: the <quote>Advanced</quote> setting is more
1976 aggressive, and will be more likely to cause problems for some sites.
1977 Experienced users only!
1981 If you prefer plain text editing to GUIs, you can of course also directly edit the
1982 the actions files with your favorite text editor. Look at
1983 <filename>default.action</filename> which is richly commented with many
1989 <sect2 id="actions-apply">
1990 <title>How Actions are Applied to Requests</title>
1992 Actions files are divided into sections. There are special sections,
1993 like the <quote><link linkend="aliases">alias</link></quote> sections which will
1994 be discussed later. For now let's concentrate on regular sections: They have a
1995 heading line (often split up to multiple lines for readability) which consist
1996 of a list of actions, separated by whitespace and enclosed in curly braces.
1997 Below that, there is a list of URL and tag patterns, each on a separate line.
2001 To determine which actions apply to a request, the URL of the request is
2002 compared to all URL patterns in each <quote>action file</quote>.
2003 Every time it matches, the list of applicable actions for the request is
2004 incrementally updated, using the heading of the section in which the
2005 pattern is located. The same is done again for tags and tag patterns later on.
2009 If multiple applying sections set the same action differently,
2010 the last match wins. If not, the effects are aggregated.
2011 E.g. a URL might match a regular section with a heading line of <literal>{
2012 +<link linkend="handle-as-image">handle-as-image</link> }</literal>,
2013 then later another one with just <literal>{
2014 +<link linkend="block">block</link> }</literal>, resulting
2015 in <emphasis>both</emphasis> actions to apply. And there may well be
2016 cases where you will want to combine actions together. Such a section then
2022 { +<literal>handle-as-image</literal> +<literal>block{Banner ads.}</literal> }
2023 # Block these as if they were images. Send no block page.
2025 media.example.com/.*banners
2026 .example.com/images/ads/</screen>
2030 You can trace this process for URL patterns and any given URL by visiting <ulink
2031 url="http://config.privoxy.org/show-url-info">http://config.privoxy.org/show-url-info</ulink>.
2035 Examples and more detail on this is provided in the Appendix, <link linkend="ACTIONSANAT">
2036 Troubleshooting: Anatomy of an Action</link> section.
2040 <!-- ~~~~~ New section ~~~~~ -->
2041 <sect2 id="af-patterns">
2042 <title>Patterns</title>
2044 As mentioned, <application>Privoxy</application> uses <quote>patterns</quote>
2045 to determine what <emphasis>actions</emphasis> might apply to which sites and
2046 pages your browser attempts to access. These <quote>patterns</quote> use wild
2047 card type <emphasis>pattern</emphasis> matching to achieve a high degree of
2048 flexibility. This allows one expression to be expanded and potentially match
2049 against many similar patterns.
2053 Generally, an URL pattern has the form
2054 <literal><domain><port>/<path></literal>, where the
2055 <literal><domain></literal>, the <literal><port></literal>
2056 and the <literal><path></literal> are optional. (This is why the special
2057 <literal>/</literal> pattern matches all URLs). Note that the protocol
2058 portion of the URL pattern (e.g. <literal>http://</literal>) should
2059 <emphasis>not</emphasis> be included in the pattern. This is assumed already!
2062 The pattern matching syntax is different for the domain and path parts of
2063 the URL. The domain part uses a simple globbing type matching technique,
2064 while the path part uses more flexible
2065 <ulink url="http://en.wikipedia.org/wiki/Regular_expressions"><quote>Regular
2066 Expressions</quote></ulink> (POSIX 1003.2).
2069 The port part of a pattern is a decimal port number preceded by a colon
2070 (<literal>:</literal>). If the domain part contains a numerical IPv6 address,
2071 it has to be put into angle brackets
2072 (<literal><</literal>, <literal>></literal>).
2077 <term><literal>www.example.com/</literal></term>
2080 is a domain-only pattern and will match any request to <literal>www.example.com</literal>,
2081 regardless of which document on that server is requested. So ALL pages in
2082 this domain would be covered by the scope of this action. Note that a
2083 simple <literal>example.com</literal> is different and would NOT match.
2088 <term><literal>www.example.com</literal></term>
2091 means exactly the same. For domain-only patterns, the trailing <literal>/</literal> may
2097 <term><literal>www.example.com/index.html</literal></term>
2100 matches all the documents on <literal>www.example.com</literal>
2101 whose name starts with <literal>/index.html</literal>.
2106 <term><literal>www.example.com/index.html$</literal></term>
2109 matches only the single document <literal>/index.html</literal>
2110 on <literal>www.example.com</literal>.
2115 <term><literal>/index.html$</literal></term>
2118 matches the document <literal>/index.html</literal>, regardless of the domain,
2119 i.e. on <emphasis>any</emphasis> web server anywhere.
2124 <term><literal>/</literal></term>
2127 Matches any URL because there's no requirement for either the
2128 domain or the path to match anything.
2133 <term><literal>:8000/</literal></term>
2136 Matches any URL pointing to TCP port 8000.
2141 <term><literal><2001:db8::1>/</literal></term>
2144 Matches any URL with the host address <literal>2001:db8::1</literal>.
2145 (Note that the real URL uses plain brackets, not angle brackets.)
2150 <term><literal>index.html</literal></term>
2153 matches nothing, since it would be interpreted as a domain name and
2154 there is no top-level domain called <literal>.html</literal>. So its
2162 <!-- ~~~~~ New section ~~~~~ -->
2163 <sect3><title>The Domain Pattern</title>
2166 The matching of the domain part offers some flexible options: if the
2167 domain starts or ends with a dot, it becomes unanchored at that end.
2173 <term><literal>.example.com</literal></term>
2176 matches any domain with first-level domain <literal>com</literal>
2177 and second-level domain <literal>example</literal>.
2178 For example <literal>www.example.com</literal>,
2179 <literal>example.com</literal> and <literal>foo.bar.baz.example.com</literal>.
2180 Note that it wouldn't match if the second-level domain was <literal>another-example</literal>.
2185 <term><literal>www.</literal></term>
2188 matches any domain that <emphasis>STARTS</emphasis> with
2189 <literal>www.</literal> (It also matches the domain
2190 <literal>www</literal> but most of the time that doesn't matter.)
2195 <term><literal>.example.</literal></term>
2198 matches any domain that <emphasis>CONTAINS</emphasis> <literal>.example.</literal>.
2199 And, by the way, also included would be any files or documents that exist
2200 within that domain since no path limitations are specified. (Correctly
2201 speaking: It matches any FQDN that contains <literal>example</literal> as
2202 a domain.) This might be <literal>www.example.com</literal>,
2203 <literal>news.example.de</literal>, or
2204 <literal>www.example.net/cgi/testing.pl</literal> for instance. All these
2212 Additionally, there are wild-cards that you can use in the domain names
2213 themselves. These work similarly to shell globbing type wild-cards:
2214 <quote>*</quote> represents zero or more arbitrary characters (this is
2216 <ulink url="http://en.wikipedia.org/wiki/Regular_expressions"><quote>Regular
2217 Expression</quote></ulink> based syntax of <quote>.*</quote>),
2218 <quote>?</quote> represents any single character (this is equivalent to the
2219 regular expression syntax of a simple <quote>.</quote>), and you can define
2220 <quote>character classes</quote> in square brackets which is similar to
2221 the same regular expression technique. All of this can be freely mixed:
2226 <term><literal>ad*.example.com</literal></term>
2229 matches <quote>adserver.example.com</quote>,
2230 <quote>ads.example.com</quote>, etc but not <quote>sfads.example.com</quote>
2235 <term><literal>*ad*.example.com</literal></term>
2238 matches all of the above, and then some.
2243 <term><literal>.?pix.com</literal></term>
2246 matches <literal>www.ipix.com</literal>,
2247 <literal>pictures.epix.com</literal>, <literal>a.b.c.d.e.upix.com</literal> etc.
2252 <term><literal>www[1-9a-ez].example.c*</literal></term>
2255 matches <literal>www1.example.com</literal>,
2256 <literal>www4.example.cc</literal>, <literal>wwwd.example.cy</literal>,
2257 <literal>wwwz.example.com</literal> etc., but <emphasis>not</emphasis>
2258 <literal>wwww.example.com</literal>.
2265 While flexible, this is not the sophistication of full regular expression based syntax.
2270 <!-- ~ End section ~ -->
2273 <!-- ~~~~~ New section ~~~~~ -->
2274 <sect3><title>The Path Pattern</title>
2277 <application>Privoxy</application> uses <quote>modern</quote> POSIX 1003.2
2278 <ulink url="http://en.wikipedia.org/wiki/Regular_expressions"><quote>Regular
2279 Expressions</quote></ulink> for matching the path portion (after the slash),
2280 and is thus more flexible.
2284 There is an <link linkend="regex">Appendix</link> with a brief quick-start into regular
2285 expressions, you also might want to have a look at your operating system's documentation
2286 on regular expressions (try <literal>man re_format</literal>).
2290 Note that the path pattern is automatically left-anchored at the <quote>/</quote>,
2291 i.e. it matches as if it would start with a <quote>^</quote> (regular expression speak
2292 for the beginning of a line).
2296 Please also note that matching in the path is <emphasis>CASE INSENSITIVE</emphasis>
2297 by default, but you can switch to case sensitive at any point in the pattern by using the
2298 <quote>(?-i)</quote> switch: <literal>www.example.com/(?-i)PaTtErN.*</literal> will match
2299 only documents whose path starts with <literal>PaTtErN</literal> in
2300 <emphasis>exactly</emphasis> this capitalization.
2305 <term><literal>.example.com/.*</literal></term>
2308 Is equivalent to just <quote>.example.com</quote>, since any documents
2309 within that domain are matched with or without the <quote>.*</quote>
2310 regular expression. This is redundant
2315 <term><literal>.example.com/.*/index.html$</literal></term>
2318 Will match any page in the domain of <quote>example.com</quote> that is
2319 named <quote>index.html</quote>, and that is part of some path. For
2320 example, it matches <quote>www.example.com/testing/index.html</quote> but
2321 NOT <quote>www.example.com/index.html</quote> because the regular
2322 expression called for at least two <quote>/'s</quote>, thus the path
2323 requirement. It also would match
2324 <quote>www.example.com/testing/index_html</quote>, because of the
2325 special meta-character <quote>.</quote>.
2330 <term><literal>.example.com/(.*/)?index\.html$</literal></term>
2333 This regular expression is conditional so it will match any page
2334 named <quote>index.html</quote> regardless of path which in this case can
2335 have one or more <quote>/'s</quote>. And this one must contain exactly
2336 <quote>.html</quote> (but does not have to end with that!).
2341 <term><literal>.example.com/(.*/)(ads|banners?|junk)</literal></term>
2344 This regular expression will match any path of <quote>example.com</quote>
2345 that contains any of the words <quote>ads</quote>, <quote>banner</quote>,
2346 <quote>banners</quote> (because of the <quote>?</quote>) or <quote>junk</quote>.
2347 The path does not have to end in these words, just contain them.
2352 <term><literal>.example.com/(.*/)(ads|banners?|junk)/.*\.(jpe?g|gif|png)$</literal></term>
2355 This is very much the same as above, except now it must end in either
2356 <quote>.jpg</quote>, <quote>.jpeg</quote>, <quote>.gif</quote> or <quote>.png</quote>. So this
2357 one is limited to common image formats.
2364 There are many, many good examples to be found in <filename>default.action</filename>,
2365 and more tutorials below in <link linkend="regex">Appendix on regular expressions</link>.
2370 <!-- ~ End section ~ -->
2373 <!-- ~~~~~ New section ~~~~~ -->
2374 <sect3 id="tag-pattern"><title>The Tag Pattern</title>
2377 Tag patterns are used to change the applying actions based on the
2378 request's tags. Tags can be created with either the
2379 <link linkend="CLIENT-HEADER-TAGGER">client-header-tagger</link>
2380 or the <link linkend="SERVER-HEADER-TAGGER">server-header-tagger</link> action.
2384 Tag patterns have to start with <quote>TAG:</quote>, so &my-app;
2385 can tell them apart from URL patterns. Everything after the colon
2386 including white space, is interpreted as a regular expression with
2387 path pattern syntax, except that tag patterns aren't left-anchored
2388 automatically (&my-app; doesn't silently add a <quote>^</quote>,
2389 you have to do it yourself if you need it).
2393 To match all requests that are tagged with <quote>foo</quote>
2394 your pattern line should be <quote>TAG:^foo$</quote>,
2395 <quote>TAG:foo</quote> would work as well, but it would also
2396 match requests whose tags contain <quote>foo</quote> somewhere.
2397 <quote>TAG: foo</quote> wouldn't work as it requires white space.
2401 Sections can contain URL and tag patterns at the same time,
2402 but tag patterns are checked after the URL patterns and thus
2403 always overrule them, even if they are located before the URL patterns.
2407 Once a new tag is added, Privoxy checks right away if it's matched by one
2408 of the tag patterns and updates the action settings accordingly. As a result
2409 tags can be used to activate other tagger actions, as long as these other
2410 taggers look for headers that haven't already be parsed.
2414 For example you could tag client requests which use the
2415 <literal>POST</literal> method,
2416 then use this tag to activate another tagger that adds a tag if cookies
2417 are sent, and then use a block action based on the cookie tag. This allows
2418 the outcome of one action, to be input into a subsequent action. However if
2419 you'd reverse the position of the described taggers, and activated the
2420 method tagger based on the cookie tagger, no method tags would be created.
2421 The method tagger would look for the request line, but at the time
2422 the cookie tag is created, the request line has already been parsed.
2426 While this is a limitation you should be aware of, this kind of
2427 indirection is seldom needed anyway and even the example doesn't
2428 make too much sense.
2435 <!-- ~ End section ~ -->
2438 <!-- ~~~~~ New section ~~~~~ -->
2440 <sect2 id="actions">
2441 <title>Actions</title>
2443 All actions are disabled by default, until they are explicitly enabled
2444 somewhere in an actions file. Actions are turned on if preceded with a
2445 <quote>+</quote>, and turned off if preceded with a <quote>-</quote>. So a
2446 <literal>+action</literal> means <quote>do that action</quote>, e.g.
2447 <literal>+block</literal> means <quote>please block URLs that match the
2448 following patterns</quote>, and <literal>-block</literal> means <quote>don't
2449 block URLs that match the following patterns, even if <literal>+block</literal>
2450 previously applied.</quote>
2455 Again, actions are invoked by placing them on a line, enclosed in curly braces and
2456 separated by whitespace, like in
2457 <literal>{+some-action -some-other-action{some-parameter}}</literal>,
2458 followed by a list of URL patterns, one per line, to which they apply.
2459 Together, the actions line and the following pattern lines make up a section
2460 of the actions file.
2464 Actions fall into three categories:
2471 Boolean, i.e the action can only be <quote>enabled</quote> or
2472 <quote>disabled</quote>. Syntax:
2476 +<replaceable class="function">name</replaceable> # enable action <replaceable class="parameter">name</replaceable>
2477 -<replaceable class="function">name</replaceable> # disable action <replaceable class="parameter">name</replaceable></screen>
2480 Example: <literal>+handle-as-image</literal>
2487 Parameterized, where some value is required in order to enable this type of action.
2492 +<replaceable class="function">name</replaceable>{<replaceable class="parameter">param</replaceable>} # enable action and set parameter to <replaceable class="parameter">param</replaceable>,
2493 # overwriting parameter from previous match if necessary
2494 -<replaceable class="function">name</replaceable> # disable action. The parameter can be omitted</screen>
2497 Note that if the URL matches multiple positive forms of a parameterized action,
2498 the last match wins, i.e. the params from earlier matches are simply ignored.
2501 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>
2507 Multi-value. These look exactly like parameterized actions,
2508 but they behave differently: If the action applies multiple times to the
2509 same URL, but with different parameters, <emphasis>all</emphasis> the parameters
2510 from <emphasis>all</emphasis> matches are remembered. This is used for actions
2511 that can be executed for the same request repeatedly, like adding multiple
2512 headers, or filtering through multiple filters. Syntax:
2516 +<replaceable class="function">name</replaceable>{<replaceable class="parameter">param</replaceable>} # enable action and add <replaceable class="parameter">param</replaceable> to the list of parameters
2517 -<replaceable class="function">name</replaceable>{<replaceable class="parameter">param</replaceable>} # remove the parameter <replaceable class="parameter">param</replaceable> from the list of parameters
2518 # If it was the last one left, disable the action.
2519 <replaceable class="parameter">-name</replaceable> # disable this action completely and remove all parameters from the list</screen>
2522 Examples: <literal>+add-header{X-Fun-Header: Some text}</literal> and
2523 <literal>+filter{html-annoyances}</literal>
2531 If nothing is specified in any actions file, no <quote>actions</quote> are
2532 taken. So in this case <application>Privoxy</application> would just be a
2533 normal, non-blocking, non-filtering proxy. You must specifically enable the
2534 privacy and blocking features you need (although the provided default actions
2535 files will give a good starting point).
2539 Later defined action sections always over-ride earlier ones of the same type.
2540 So exceptions to any rules you make, should come in the latter part of the file (or
2541 in a file that is processed later when using multiple actions files such
2542 as <filename>user.action</filename>). For multi-valued actions, the actions
2543 are applied in the order they are specified. Actions files are processed in
2544 the order they are defined in <filename>config</filename> (the default
2545 installation has three actions files). It also quite possible for any given
2546 URL to match more than one <quote>pattern</quote> (because of wildcards and
2547 regular expressions), and thus to trigger more than one set of actions! Last
2551 <!-- start actions listing -->
2553 The list of valid <application>Privoxy</application> actions are:
2557 <!-- ********************************************************** -->
2558 <!-- Please note the below defined actions use id's that are -->
2559 <!-- probably linked from other places, so please don't change. -->
2561 <!-- ********************************************************** -->
2564 <!-- ~~~~~ New section ~~~~~ -->
2566 <sect3 renderas="sect4" id="add-header">
2567 <title>add-header</title>
2571 <term>Typical use:</term>
2573 <para>Confuse log analysis, custom applications</para>
2578 <term>Effect:</term>
2581 Sends a user defined HTTP header to the web server.
2588 <!-- boolean, parameterized, Multi-value -->
2590 <para>Multi-value.</para>
2595 <term>Parameter:</term>
2598 Any string value is possible. Validity of the defined HTTP headers is not checked.
2599 It is recommended that you use the <quote><literal>X-</literal></quote> prefix
2609 This action may be specified multiple times, in order to define multiple
2610 headers. This is rarely needed for the typical user. If you don't know what
2611 <quote>HTTP headers</quote> are, you definitely don't need to worry about this
2615 Headers added by this action are not modified by other actions.
2621 <term>Example usage:</term>
2624 <screen>+add-header{X-User-Tracking: sucks}</screen>
2632 <!-- ~~~~~ New section ~~~~~ -->
2633 <sect3 renderas="sect4" id="block">
2634 <title>block</title>
2638 <term>Typical use:</term>
2640 <para>Block ads or other unwanted content</para>
2645 <term>Effect:</term>
2648 Requests for URLs to which this action applies are blocked, i.e. the
2649 requests are trapped by &my-app; and the requested URL is never retrieved,
2650 but is answered locally with a substitute page or image, as determined by
2652 linkend="handle-as-image">handle-as-image</link></literal>,
2654 linkend="set-image-blocker">set-image-blocker</link></literal>, and
2656 linkend="handle-as-empty-document">handle-as-empty-document</link></literal> actions.
2664 <!-- boolean, parameterized, Multi-value -->
2666 <para>Parameterized.</para>
2671 <term>Parameter:</term>
2673 <para>A block reason that should be given to the user.</para>
2681 <application>Privoxy</application> sends a special <quote>BLOCKED</quote> page
2682 for requests to blocked pages. This page contains the block reason given as
2683 parameter, a link to find out why the block action applies, and a click-through
2684 to the blocked content (the latter only if the force feature is available and
2688 A very important exception occurs if <emphasis>both</emphasis>
2689 <literal>block</literal> and <literal><link linkend="handle-as-image">handle-as-image</link></literal>,
2690 apply to the same request: it will then be replaced by an image. If
2691 <literal><link linkend="set-image-blocker">set-image-blocker</link></literal>
2692 (see below) also applies, the type of image will be determined by its parameter,
2693 if not, the standard checkerboard pattern is sent.
2696 It is important to understand this process, in order
2697 to understand how <application>Privoxy</application> deals with
2698 ads and other unwanted content. Blocking is a core feature, and one
2699 upon which various other features depend.
2702 The <literal><link linkend="filter">filter</link></literal>
2703 action can perform a very similar task, by <quote>blocking</quote>
2704 banner images and other content through rewriting the relevant URLs in the
2705 document's HTML source, so they don't get requested in the first place.
2706 Note that this is a totally different technique, and it's easy to confuse the two.
2712 <term>Example usage (section):</term>
2715 <screen>{+block{No nasty stuff for you.}}
2716 # Block and replace with "blocked" page
2717 .nasty-stuff.example.com
2719 {+block{Doubleclick banners.} +handle-as-image}
2720 # Block and replace with image
2724 {+block{Layered ads.} +handle-as-empty-document}
2725 # Block and then ignore
2726 adserver.example.net/.*\.js$</screen>
2736 <!-- ~~~~~ New section ~~~~~ -->
2737 <sect3 renderas="sect4" id="change-x-forwarded-for">
2738 <title>change-x-forwarded-for</title>
2742 <term>Typical use:</term>
2744 <para>Improve privacy by not forwarding the source of the request in the HTTP headers.</para>
2749 <term>Effect:</term>
2752 Deletes the <quote>X-Forwarded-For:</quote> HTTP header from the client request,
2760 <!-- Boolean, Parameterized, Multi-value -->
2762 <para>Parameterized.</para>
2767 <term>Parameter:</term>
2771 <para><quote>block</quote> to delete the header.</para>
2775 <quote>add</quote> to create the header (or append
2776 the client's IP address to an already existing one).
2787 It is safe and recommended to use <literal>block</literal>.
2790 Forwarding the source address of the request may make
2791 sense in some multi-user setups but is also a privacy risk.
2796 <term>Example usage:</term>
2799 <screen>+change-x-forwarded-for{block}</screen>
2806 <!-- ~~~~~ New section ~~~~~ -->
2807 <sect3 renderas="sect4" id="client-header-filter">
2808 <title>client-header-filter</title>
2812 <term>Typical use:</term>
2815 Rewrite or remove single client headers.
2821 <term>Effect:</term>
2824 All client headers to which this action applies are filtered on-the-fly through
2825 the specified regular expression based substitutions.
2832 <!-- boolean, parameterized, Multi-value -->
2834 <para>Parameterized.</para>
2839 <term>Parameter:</term>
2842 The name of a client-header filter, as defined in one of the
2843 <link linkend="filter-file">filter files</link>.
2852 Client-header filters are applied to each header on its own, not to
2853 all at once. This makes it easier to diagnose problems, but on the downside
2854 you can't write filters that only change header x if header y's value is z.
2855 You can do that by using tags though.
2858 Client-header filters are executed after the other header actions have finished
2859 and use their output as input.
2862 If the request URI gets changed, &my-app; will detect that and use the new
2863 one. This can be used to rewrite the request destination behind the client's
2864 back, for example to specify a Tor exit relay for certain requests.
2867 Please refer to the <link linkend="filter-file">filter file chapter</link>
2868 to learn which client-header filters are available by default, and how to
2876 <term>Example usage (section):</term>
2880 # Hide Tor exit notation in Host and Referer Headers
2881 {+client-header-filter{hide-tor-exit-notation}}
2892 <!-- ~~~~~ New section ~~~~~ -->
2893 <sect3 renderas="sect4" id="client-header-tagger">
2894 <title>client-header-tagger</title>
2898 <term>Typical use:</term>
2901 Block requests based on their headers.
2907 <term>Effect:</term>
2910 Client headers to which this action applies are filtered on-the-fly through
2911 the specified regular expression based substitutions, the result is used as
2919 <!-- boolean, parameterized, Multi-value -->
2921 <para>Parameterized.</para>
2926 <term>Parameter:</term>
2929 The name of a client-header tagger, as defined in one of the
2930 <link linkend="filter-file">filter files</link>.
2939 Client-header taggers are applied to each header on its own,
2940 and as the header isn't modified, each tagger <quote>sees</quote>
2944 Client-header taggers are the first actions that are executed
2945 and their tags can be used to control every other action.
2951 <term>Example usage (section):</term>
2955 # Tag every request with the User-Agent header
2956 {+client-header-tagger{user-agent}}
2959 # Tagging itself doesn't change the action
2960 # settings, sections with TAG patterns do:
2962 # If it's a download agent, use a different forwarding proxy,
2963 # show the real User-Agent and make sure resume works.
2964 {+forward-override{forward-socks5 10.0.0.2:2222 .} \
2965 -hide-if-modified-since \
2966 -overwrite-last-modified \
2971 TAG:^User-Agent: NetBSD-ftp/
2972 TAG:^User-Agent: Novell ZYPP Installer
2973 TAG:^User-Agent: RPM APT-HTTP/
2974 TAG:^User-Agent: fetch libfetch/
2975 TAG:^User-Agent: Ubuntu APT-HTTP/
2976 TAG:^User-Agent: MPlayer/
2981 # Tag all requests with the Range header set
2982 {+client-header-tagger{range-requests}}
2985 # Disable filtering for the tagged requests.
2987 # With filtering enabled Privoxy would remove the Range headers
2988 # to be able to filter the whole response. The downside is that
2989 # it prevents clients from resuming downloads or skipping over
2990 # parts of multimedia files.
2991 {-filter -deanimate-gifs}
3002 <!-- ~~~~~ New section ~~~~~ -->
3003 <sect3 renderas="sect4" id="content-type-overwrite">
3004 <title>content-type-overwrite</title>
3008 <term>Typical use:</term>
3010 <para>Stop useless download menus from popping up, or change the browser's rendering mode</para>
3015 <term>Effect:</term>
3018 Replaces the <quote>Content-Type:</quote> HTTP server header.
3025 <!-- Boolean, Parameterized, Multi-value -->
3027 <para>Parameterized.</para>
3032 <term>Parameter:</term>
3044 The <quote>Content-Type:</quote> HTTP server header is used by the
3045 browser to decide what to do with the document. The value of this
3046 header can cause the browser to open a download menu instead of
3047 displaying the document by itself, even if the document's format is
3048 supported by the browser.
3051 The declared content type can also affect which rendering mode
3052 the browser chooses. If XHTML is delivered as <quote>text/html</quote>,
3053 many browsers treat it as yet another broken HTML document.
3054 If it is send as <quote>application/xml</quote>, browsers with
3055 XHTML support will only display it, if the syntax is correct.
3058 If you see a web site that proudly uses XHTML buttons, but sets
3059 <quote>Content-Type: text/html</quote>, you can use &my-app;
3060 to overwrite it with <quote>application/xml</quote> and validate
3061 the web master's claim inside your XHTML-supporting browser.
3062 If the syntax is incorrect, the browser will complain loudly.
3065 You can also go the opposite direction: if your browser prints
3066 error messages instead of rendering a document falsely declared
3067 as XHTML, you can overwrite the content type with
3068 <quote>text/html</quote> and have it rendered as broken HTML document.
3071 By default <literal>content-type-overwrite</literal> only replaces
3072 <quote>Content-Type:</quote> headers that look like some kind of text.
3073 If you want to overwrite it unconditionally, you have to combine it with
3074 <literal><link linkend="force-text-mode">force-text-mode</link></literal>.
3075 This limitation exists for a reason, think twice before circumventing it.
3078 Most of the time it's easier to replace this action with a custom
3079 <literal><link linkend="server-header-filter">server-header filter</link></literal>.
3080 It allows you to activate it for every document of a certain site and it will still
3081 only replace the content types you aimed at.
3084 Of course you can apply <literal>content-type-overwrite</literal>
3085 to a whole site and then make URL based exceptions, but it's a lot
3086 more work to get the same precision.
3092 <term>Example usage (sections):</term>
3095 <screen># Check if www.example.net/ really uses valid XHTML
3096 { +content-type-overwrite{application/xml} }
3099 # but leave the content type unmodified if the URL looks like a style sheet
3100 {-content-type-overwrite}
3101 www.example.net/.*\.css$
3102 www.example.net/.*style
3111 <!-- ~~~~~ New section ~~~~~ -->
3112 <sect3 renderas="sect4" id="crunch-client-header">
3116 <title>crunch-client-header</title>
3120 <term>Typical use:</term>
3122 <para>Remove a client header <application>Privoxy</application> has no dedicated action for.</para>
3127 <term>Effect:</term>
3130 Deletes every header sent by the client that contains the string the user supplied as parameter.
3137 <!-- Boolean, Parameterized, Multi-value -->
3139 <para>Parameterized.</para>
3144 <term>Parameter:</term>
3156 This action allows you to block client headers for which no dedicated
3157 <application>Privoxy</application> action exists.
3158 <application>Privoxy</application> will remove every client header that
3159 contains the string you supplied as parameter.
3162 Regular expressions are <emphasis>not supported</emphasis> and you can't
3163 use this action to block different headers in the same request, unless
3164 they contain the same string.
3167 <literal>crunch-client-header</literal> is only meant for quick tests.
3168 If you have to block several different headers, or only want to modify
3169 parts of them, you should use a
3170 <literal><link linkend="client-header-filter">client-header filter</link></literal>.
3174 Don't block any header without understanding the consequences.
3181 <term>Example usage (section):</term>
3184 <screen># Block the non-existent "Privacy-Violation:" client header
3185 { +crunch-client-header{Privacy-Violation:} }
3195 <!-- ~~~~~ New section ~~~~~ -->
3196 <sect3 renderas="sect4" id="crunch-if-none-match">
3197 <title>crunch-if-none-match</title>
3203 <term>Typical use:</term>
3205 <para>Prevent yet another way to track the user's steps between sessions.</para>
3210 <term>Effect:</term>
3213 Deletes the <quote>If-None-Match:</quote> HTTP client header.
3220 <!-- Boolean, Parameterized, Multi-value -->
3222 <para>Boolean.</para>
3227 <term>Parameter:</term>
3239 Removing the <quote>If-None-Match:</quote> HTTP client header
3240 is useful for filter testing, where you want to force a real
3241 reload instead of getting status code <quote>304</quote> which
3242 would cause the browser to use a cached copy of the page.
3245 It is also useful to make sure the header isn't used as a cookie
3246 replacement (unlikely but possible).
3249 Blocking the <quote>If-None-Match:</quote> header shouldn't cause any
3250 caching problems, as long as the <quote>If-Modified-Since:</quote> header
3251 isn't blocked or missing as well.
3254 It is recommended to use this action together with
3255 <literal><link linkend="hide-if-modified-since">hide-if-modified-since</link></literal>
3257 <literal><link linkend="overwrite-last-modified">overwrite-last-modified</link></literal>.
3263 <term>Example usage (section):</term>
3266 <screen># Let the browser revalidate cached documents but don't
3267 # allow the server to use the revalidation headers for user tracking.
3268 {+hide-if-modified-since{-60} \
3269 +overwrite-last-modified{randomize} \
3270 +crunch-if-none-match}
3279 <!-- ~~~~~ New section ~~~~~ -->
3280 <sect3 renderas="sect4" id="crunch-incoming-cookies">
3281 <title>crunch-incoming-cookies</title>
3285 <term>Typical use:</term>
3288 Prevent the web server from setting HTTP cookies on your system
3294 <term>Effect:</term>
3297 Deletes any <quote>Set-Cookie:</quote> HTTP headers from server replies.
3304 <!-- Boolean, Parameterized, Multi-value -->
3306 <para>Boolean.</para>
3311 <term>Parameter:</term>
3323 This action is only concerned with <emphasis>incoming</emphasis> HTTP cookies. For
3324 <emphasis>outgoing</emphasis> HTTP cookies, use
3325 <literal><link linkend="crunch-outgoing-cookies">crunch-outgoing-cookies</link></literal>.
3326 Use <emphasis>both</emphasis> to disable HTTP cookies completely.
3329 It makes <emphasis>no sense at all</emphasis> to use this action in conjunction
3330 with the <literal><link linkend="session-cookies-only">session-cookies-only</link></literal> action,
3331 since it would prevent the session cookies from being set. See also
3332 <literal><link linkend="filter-content-cookies">filter-content-cookies</link></literal>.
3338 <term>Example usage:</term>
3341 <screen>+crunch-incoming-cookies</screen>
3349 <!-- ~~~~~ New section ~~~~~ -->
3350 <sect3 renderas="sect4" id="crunch-server-header">
3351 <title>crunch-server-header</title>
3357 <term>Typical use:</term>
3359 <para>Remove a server header <application>Privoxy</application> has no dedicated action for.</para>
3364 <term>Effect:</term>
3367 Deletes every header sent by the server that contains the string the user supplied as parameter.
3374 <!-- Boolean, Parameterized, Multi-value -->
3376 <para>Parameterized.</para>
3381 <term>Parameter:</term>
3393 This action allows you to block server headers for which no dedicated
3394 <application>Privoxy</application> action exists. <application>Privoxy</application>
3395 will remove every server header that contains the string you supplied as parameter.
3398 Regular expressions are <emphasis>not supported</emphasis> and you can't
3399 use this action to block different headers in the same request, unless
3400 they contain the same string.
3403 <literal>crunch-server-header</literal> is only meant for quick tests.
3404 If you have to block several different headers, or only want to modify
3405 parts of them, you should use a custom
3406 <literal><link linkend="server-header-filter">server-header filter</link></literal>.
3410 Don't block any header without understanding the consequences.
3417 <term>Example usage (section):</term>
3420 <screen># Crunch server headers that try to prevent caching
3421 { +crunch-server-header{no-cache} }
3430 <!-- ~~~~~ New section ~~~~~ -->
3431 <sect3 renderas="sect4" id="crunch-outgoing-cookies">
3432 <title>crunch-outgoing-cookies</title>
3436 <term>Typical use:</term>
3439 Prevent the web server from reading any HTTP cookies from your system
3445 <term>Effect:</term>
3448 Deletes any <quote>Cookie:</quote> HTTP headers from client requests.
3455 <!-- Boolean, Parameterized, Multi-value -->
3457 <para>Boolean.</para>
3462 <term>Parameter:</term>
3474 This action is only concerned with <emphasis>outgoing</emphasis> HTTP cookies. For
3475 <emphasis>incoming</emphasis> HTTP cookies, use
3476 <literal><link linkend="crunch-incoming-cookies">crunch-incoming-cookies</link></literal>.
3477 Use <emphasis>both</emphasis> to disable HTTP cookies completely.
3480 It makes <emphasis>no sense at all</emphasis> to use this action in conjunction
3481 with the <literal><link linkend="session-cookies-only">session-cookies-only</link></literal> action,
3482 since it would prevent the session cookies from being read.
3488 <term>Example usage:</term>
3491 <screen>+crunch-outgoing-cookies</screen>
3500 <!-- ~~~~~ New section ~~~~~ -->
3501 <sect3 renderas="sect4" id="deanimate-gifs">
3502 <title>deanimate-gifs</title>
3506 <term>Typical use:</term>
3508 <para>Stop those annoying, distracting animated GIF images.</para>
3513 <term>Effect:</term>
3516 De-animate GIF animations, i.e. reduce them to their first or last image.
3523 <!-- boolean, parameterized, Multi-value -->
3525 <para>Parameterized.</para>
3530 <term>Parameter:</term>
3533 <quote>last</quote> or <quote>first</quote>
3542 This will also shrink the images considerably (in bytes, not pixels!). If
3543 the option <quote>first</quote> is given, the first frame of the animation
3544 is used as the replacement. If <quote>last</quote> is given, the last
3545 frame of the animation is used instead, which probably makes more sense for
3546 most banner animations, but also has the risk of not showing the entire
3547 last frame (if it is only a delta to an earlier frame).
3550 You can safely use this action with patterns that will also match non-GIF
3551 objects, because no attempt will be made at anything that doesn't look like
3558 <term>Example usage:</term>
3561 <screen>+deanimate-gifs{last}</screen>
3568 <!-- ~~~~~ New section ~~~~~ -->
3569 <sect3 renderas="sect4" id="downgrade-http-version">
3570 <title>downgrade-http-version</title>
3574 <term>Typical use:</term>
3576 <para>Work around (very rare) problems with HTTP/1.1</para>
3581 <term>Effect:</term>
3584 Downgrades HTTP/1.1 client requests and server replies to HTTP/1.0.
3591 <!-- boolean, parameterized, Multi-value -->
3593 <para>Boolean.</para>
3598 <term>Parameter:</term>
3610 This is a left-over from the time when <application>Privoxy</application>
3611 didn't support important HTTP/1.1 features well. It is left here for the
3612 unlikely case that you experience HTTP/1.1-related problems with some server
3616 Note that enabling this action is only a workaround. It should not
3617 be enabled for sites that work without it. While it shouldn't break
3618 any pages, it has an (usually negative) performance impact.
3621 If you come across a site where enabling this action helps, please report it,
3622 so the cause of the problem can be analyzed. If the problem turns out to be
3623 caused by a bug in <application>Privoxy</application> it should be
3624 fixed so the following release works without the work around.
3630 <term>Example usage (section):</term>
3633 <screen>{+downgrade-http-version}
3634 problem-host.example.com</screen>
3642 <!-- ~~~~~ New section ~~~~~ -->
3643 <sect3 renderas="sect4" id="fast-redirects">
3644 <title>fast-redirects</title>
3648 <term>Typical use:</term>
3650 <para>Fool some click-tracking scripts and speed up indirect links.</para>
3655 <term>Effect:</term>
3658 Detects redirection URLs and redirects the browser without contacting
3659 the redirection server first.
3666 <!-- boolean, parameterized, Multi-value -->
3668 <para>Parameterized.</para>
3673 <term>Parameter:</term>
3678 <quote>simple-check</quote> to just search for the string <quote>http://</quote>
3679 to detect redirection URLs.
3684 <quote>check-decoded-url</quote> to decode URLs (if necessary) before searching
3685 for redirection URLs.
3696 Many sites, like yahoo.com, don't just link to other sites. Instead, they
3697 will link to some script on their own servers, giving the destination as a
3698 parameter, which will then redirect you to the final target. URLs
3699 resulting from this scheme typically look like:
3700 <quote>http://www.example.org/click-tracker.cgi?target=http%3a//www.example.net/</quote>.
3703 Sometimes, there are even multiple consecutive redirects encoded in the
3704 URL. These redirections via scripts make your web browsing more traceable,
3705 since the server from which you follow such a link can see where you go
3706 to. Apart from that, valuable bandwidth and time is wasted, while your
3707 browser asks the server for one redirect after the other. Plus, it feeds
3711 This feature is currently not very smart and is scheduled for improvement.
3712 If it is enabled by default, you will have to create some exceptions to
3713 this action. It can lead to failures in several ways:
3716 Not every URLs with other URLs as parameters is evil.
3717 Some sites offer a real service that requires this information to work.
3718 For example a validation service needs to know, which document to validate.
3719 <literal>fast-redirects</literal> assumes that every URL parameter that
3720 looks like another URL is a redirection target, and will always redirect to
3721 the last one. Most of the time the assumption is correct, but if it isn't,
3722 the user gets redirected anyway.
3725 Another failure occurs if the URL contains other parameters after the URL parameter.
3727 <quote>http://www.example.org/?redirect=http%3a//www.example.net/&foo=bar</quote>.
3728 contains the redirection URL <quote>http://www.example.net/</quote>,
3729 followed by another parameter. <literal>fast-redirects</literal> doesn't know that
3730 and will cause a redirect to <quote>http://www.example.net/&foo=bar</quote>.
3731 Depending on the target server configuration, the parameter will be silently ignored
3732 or lead to a <quote>page not found</quote> error. You can prevent this problem by
3733 first using the <literal><link linkend="redirect">redirect</link></literal> action
3734 to remove the last part of the URL, but it requires a little effort.
3737 To detect a redirection URL, <literal>fast-redirects</literal> only
3738 looks for the string <quote>http://</quote>, either in plain text
3739 (invalid but often used) or encoded as <quote>http%3a//</quote>.
3740 Some sites use their own URL encoding scheme, encrypt the address
3741 of the target server or replace it with a database id. In theses cases
3742 <literal>fast-redirects</literal> is fooled and the request reaches the
3743 redirection server where it probably gets logged.
3749 <term>Example usage:</term>
3753 { +fast-redirects{simple-check} }
3756 { +fast-redirects{check-decoded-url} }
3757 another.example.com/testing</screen>
3766 <!-- ~~~~~ New section ~~~~~ -->
3767 <sect3 renderas="sect4" id="filter">
3768 <title>filter</title>
3772 <term>Typical use:</term>
3774 <para>Get rid of HTML and JavaScript annoyances, banner advertisements (by size),
3775 do fun text replacements, add personalized effects, etc.</para>
3780 <term>Effect:</term>
3783 All instances of text-based type, most notably HTML and JavaScript, to which
3784 this action applies, can be filtered on-the-fly through the specified regular
3785 expression based substitutions. (Note: as of version 3.0.3 plain text documents
3786 are exempted from filtering, because web servers often use the
3787 <literal>text/plain</literal> MIME type for all files whose type they don't know.)
3794 <!-- boolean, parameterized, Multi-value -->
3796 <para>Parameterized.</para>
3801 <term>Parameter:</term>
3804 The name of a content filter, as defined in the <link linkend="filter-file">filter file</link>.
3805 Filters can be defined in one or more files as defined by the
3806 <literal><link linkend="filterfile">filterfile</link></literal>
3807 option in the <link linkend="config">config file</link>.
3808 <filename>default.filter</filename> is the collection of filters
3809 supplied by the developers. Locally defined filters should go
3810 in their own file, such as <filename>user.filter</filename>.
3813 When used in its negative form,
3814 and without parameters, <emphasis>all</emphasis> filtering is completely disabled.
3823 For your convenience, there are a number of pre-defined filters available
3824 in the distribution filter file that you can use. See the examples below for
3828 Filtering requires buffering the page content, which may appear to
3829 slow down page rendering since nothing is displayed until all content has
3830 passed the filters. (The total time until the page is completely rendered
3831 doesn't change much, but it may be perceived as slower since the page is
3832 not incrementally displayed.)
3833 This effect will be more noticeable on slower connections.
3836 <quote>Rolling your own</quote>
3837 filters requires a knowledge of
3838 <ulink url="http://en.wikipedia.org/wiki/Regular_expressions"><quote>Regular
3839 Expressions</quote></ulink> and
3840 <ulink url="http://en.wikipedia.org/wiki/Html"><quote>HTML</quote></ulink>.
3841 This is very powerful feature, and potentially very intrusive.
3842 Filters should be used with caution, and where an equivalent
3843 <quote>action</quote> is not available.
3846 The amount of data that can be filtered is limited to the
3847 <literal><link linkend="buffer-limit">buffer-limit</link></literal>
3848 option in the main <link linkend="config">config file</link>. The
3849 default is 4096 KB (4 Megs). Once this limit is exceeded, the buffered
3850 data, and all pending data, is passed through unfiltered.
3853 Inappropriate MIME types, such as zipped files, are not filtered at all.
3854 (Again, only text-based types except plain text). Encrypted SSL data
3855 (from HTTPS servers) cannot be filtered either, since this would violate
3856 the integrity of the secure transaction. In some situations it might
3857 be necessary to protect certain text, like source code, from filtering
3858 by defining appropriate <literal>-filter</literal> exceptions.
3861 Compressed content can't be filtered either, but if &my-app;
3862 is compiled with zlib support and a supported compression algorithm
3863 is used (gzip or deflate), &my-app; can first decompress the content
3867 If you use a &my-app; version without zlib support, but want filtering to work on
3868 as much documents as possible, even those that would normally be sent compressed,
3869 you must use the <literal><link linkend="prevent-compression">prevent-compression</link></literal>
3870 action in conjunction with <literal>filter</literal>.
3873 Content filtering can achieve some of the same effects as the
3874 <literal><link linkend="block">block</link></literal>
3875 action, i.e. it can be used to block ads and banners. But the mechanism
3876 works quite differently. One effective use, is to block ad banners
3877 based on their size (see below), since many of these seem to be somewhat
3881 <link linkend="contact">Feedback</link> with suggestions for new or
3882 improved filters is particularly welcome!
3885 The below list has only the names and a one-line description of each
3886 predefined filter. There are <link linkend="predefined-filters">more
3887 verbose explanations</link> of what these filters do in the <link
3888 linkend="filter-file">filter file chapter</link>.
3894 <term>Example usage (with filters from the distribution <filename>default.filter</filename> file).
3895 See <link linkend="PREDEFINED-FILTERS">the Predefined Filters section</link> for
3896 more explanation on each:</term>
3899 <anchor id="filter-js-annoyances">
3900 <screen>+filter{js-annoyances} # Get rid of particularly annoying JavaScript abuse.</screen>
3903 <anchor id="filter-js-events">
3904 <screen>+filter{js-events} # Kill all JS event bindings and timers (Radically destructive! Only for extra nasty sites).</screen>
3907 <anchor id="filter-html-annoyances">
3908 <screen>+filter{html-annoyances} # Get rid of particularly annoying HTML abuse.</screen>
3911 <anchor id="filter-content-cookies">
3912 <screen>+filter{content-cookies} # Kill cookies that come in the HTML or JS content.</screen>
3915 <anchor id="filter-refresh-tags">
3916 <screen>+filter{refresh-tags} # Kill automatic refresh tags (for dial-on-demand setups).</screen>
3919 <anchor id="filter-unsolicited-popups">
3920 <screen>+filter{unsolicited-popups} # Disable only unsolicited pop-up windows. Useful if your browser lacks this ability.</screen>
3923 <anchor id="filter-all-popups">
3924 <screen>+filter{all-popups} # Kill all popups in JavaScript and HTML. Useful if your browser lacks this ability.</screen>
3927 <anchor id="filter-img-reorder">
3928 <screen>+filter{img-reorder} # Reorder attributes in <img> tags to make the banners-by-* filters more effective.</screen>
3931 <anchor id="filter-banners-by-size">
3932 <screen>+filter{banners-by-size} # Kill banners by size.</screen>
3935 <anchor id="filter-banners-by-link">
3936 <screen>+filter{banners-by-link} # Kill banners by their links to known clicktrackers.</screen>
3939 <anchor id="filter-webbugs">
3940 <screen>+filter{webbugs} # Squish WebBugs (1x1 invisible GIFs used for user tracking).</screen>
3943 <anchor id="filter-tiny-textforms">
3944 <screen>+filter{tiny-textforms} # Extend those tiny textareas up to 40x80 and kill the hard wrap.</screen>
3947 <anchor id="filter-jumping-windows">
3948 <screen>+filter{jumping-windows} # Prevent windows from resizing and moving themselves.</screen>
3951 <anchor id="filter-frameset-borders">
3952 <screen>+filter{frameset-borders} # Give frames a border and make them resizable.</screen>
3955 <anchor id="filter-demoronizer">
3956 <screen>+filter{demoronizer} # Fix MS's non-standard use of standard charsets.</screen>
3959 <anchor id="filter-shockwave-flash">
3960 <screen>+filter{shockwave-flash} # Kill embedded Shockwave Flash objects.</screen>
3963 <anchor id="filter-quicktime-kioskmode">
3964 <screen>+filter{quicktime-kioskmode} # Make Quicktime movies saveable.</screen>
3967 <anchor id="filter-fun">
3968 <screen>+filter{fun} # Text replacements for subversive browsing fun!</screen>
3971 <anchor id="filter-crude-parental">
3972 <screen>+filter{crude-parental} # Crude parental filtering. Note that this filter doesn't work reliably.</screen>
3975 <anchor id="filter-ie-exploits">
3976 <screen>+filter{ie-exploits} # Disable some known Internet Explorer bug exploits.</screen>
3979 <anchor id="filter-site-specifics">
3980 <screen>+filter{site-specifics} # Cure for site-specific problems. Don't apply generally!</screen>
3983 <anchor id="filter-no-ping">
3984 <screen>+filter{no-ping} # Removes non-standard ping attributes in <a> and <area> tags.</screen>
3987 <anchor id="filter-google">
3988 <screen>+filter{google} # CSS-based block for Google text ads. Also removes a width limitation and the toolbar advertisement.</screen>
3991 <anchor id="filter-yahoo">
3992 <screen>+filter{yahoo} # CSS-based block for Yahoo text ads. Also removes a width limitation.</screen>
3995 <anchor id="filter-msn">
3996 <screen>+filter{msn} # CSS-based block for MSN text ads. Also removes tracking URLs and a width limitation.</screen>
3999 <anchor id="filter-blogspot">
4000 <screen>+filter{blogspot} # Cleans up some Blogspot blogs. Read the fine print before using this.</screen>
4008 <!-- ~~~~~ New section ~~~~~ -->
4009 <sect3 renderas="sect4" id="force-text-mode">
4010 <title>force-text-mode</title>
4016 <term>Typical use:</term>
4018 <para>Force <application>Privoxy</application> to treat a document as if it was in some kind of <emphasis>text</emphasis> format. </para>
4023 <term>Effect:</term>
4026 Declares a document as text, even if the <quote>Content-Type:</quote> isn't detected as such.
4033 <!-- Boolean, Parameterized, Multi-value -->
4035 <para>Boolean.</para>
4040 <term>Parameter:</term>
4052 As explained <literal><link linkend="filter">above</link></literal>,
4053 <application>Privoxy</application> tries to only filter files that are
4054 in some kind of text format. The same restrictions apply to
4055 <literal><link linkend="content-type-overwrite">content-type-overwrite</link></literal>.
4056 <literal>force-text-mode</literal> declares a document as text,
4057 without looking at the <quote>Content-Type:</quote> first.
4061 Think twice before activating this action. Filtering binary data
4062 with regular expressions can cause file damage.
4069 <term>Example usage:</term>
4082 <!-- ~~~~~ New section ~~~~~ -->
4083 <sect3 renderas="sect4" id="forward-override">
4084 <title>forward-override</title>
4090 <term>Typical use:</term>
4092 <para>Change the forwarding settings based on User-Agent or request origin</para>
4097 <term>Effect:</term>
4100 Overrules the forward directives in the configuration file.
4107 <!-- Boolean, Parameterized, Multi-value -->
4109 <para>Multi-value.</para>
4114 <term>Parameter:</term>
4118 <para><quote>forward .</quote> to use a direct connection without any additional proxies.</para>
4122 <quote>forward 127.0.0.1:8123</quote> to use the HTTP proxy listening at 127.0.0.1 port 8123.
4127 <quote>forward-socks4a 127.0.0.1:9050 .</quote> to use the socks4a proxy listening at
4128 127.0.0.1 port 9050. Replace <quote>forward-socks4a</quote> with <quote>forward-socks4</quote>
4129 to use a socks4 connection (with local DNS resolution) instead, use <quote>forward-socks5</quote>
4130 for socks5 connections (with remote DNS resolution).
4135 <quote>forward-socks4a 127.0.0.1:9050 proxy.example.org:8000</quote> to use the socks4a proxy
4136 listening at 127.0.0.1 port 9050 to reach the HTTP proxy listening at proxy.example.org port 8000.
4137 Replace <quote>forward-socks4a</quote> with <quote>forward-socks4</quote> to use a socks4 connection
4138 (with local DNS resolution) instead, use <quote>forward-socks5</quote>
4139 for socks5 connections (with remote DNS resolution).
4150 This action takes parameters similar to the
4151 <link linkend="forwarding">forward</link> directives in the configuration
4152 file, but without the URL pattern. It can be used as replacement, but normally it's only
4153 used in cases where matching based on the request URL isn't sufficient.
4157 Please read the description for the <link linkend="forwarding">forward</link> directives before
4158 using this action. Forwarding to the wrong people will reduce your privacy and increase the
4159 chances of man-in-the-middle attacks.
4162 If the ports are missing or invalid, default values will be used. This might change
4163 in the future and you shouldn't rely on it. Otherwise incorrect syntax causes Privoxy
4167 Use the <ulink url="http://config.privoxy.org/show-url-info">show-url-info CGI page</ulink>
4168 to verify that your forward settings do what you thought the do.
4175 <term>Example usage:</term>
4179 # Always use direct connections for requests previously tagged as
4180 # <quote>User-Agent: fetch libfetch/2.0</quote> and make sure
4181 # resuming downloads continues to work.
4182 # This way you can continue to use Tor for your normal browsing,
4183 # without overloading the Tor network with your FreeBSD ports updates
4184 # or downloads of bigger files like ISOs.
4185 # Note that HTTP headers are easy to fake and therefore their
4186 # values are as (un)trustworthy as your clients and users.
4187 {+forward-override{forward .} \
4188 -hide-if-modified-since \
4189 -overwrite-last-modified \
4191 TAG:^User-Agent: fetch libfetch/2\.0$
4200 <!-- ~~~~~ New section ~~~~~ -->
4201 <sect3 renderas="sect4" id="handle-as-empty-document">
4202 <title>handle-as-empty-document</title>
4208 <term>Typical use:</term>
4210 <para>Mark URLs that should be replaced by empty documents <emphasis>if they get blocked</emphasis></para>
4215 <term>Effect:</term>
4218 This action alone doesn't do anything noticeable. It just marks URLs.
4219 If the <literal><link linkend="block">block</link></literal> action <emphasis>also applies</emphasis>,
4220 the presence or absence of this mark decides whether an HTML <quote>BLOCKED</quote>
4221 page, or an empty document will be sent to the client as a substitute for the blocked content.
4222 The <emphasis>empty</emphasis> document isn't literally empty, but actually contains a single space.
4229 <!-- Boolean, Parameterized, Multi-value -->
4231 <para>Boolean.</para>
4236 <term>Parameter:</term>
4248 Some browsers complain about syntax errors if JavaScript documents
4249 are blocked with <application>Privoxy's</application>
4250 default HTML page; this option can be used to silence them.
4251 And of course this action can also be used to eliminate the &my-app;
4252 BLOCKED message in frames.
4255 The content type for the empty document can be specified with
4256 <literal><link linkend="content-type-overwrite">content-type-overwrite{}</link></literal>,
4257 but usually this isn't necessary.
4263 <term>Example usage:</term>
4266 <screen># Block all documents on example.org that end with ".js",
4267 # but send an empty document instead of the usual HTML message.
4268 {+block{Blocked JavaScript} +handle-as-empty-document}
4278 <!-- ~~~~~ New section ~~~~~ -->
4279 <sect3 renderas="sect4" id="handle-as-image">
4280 <title>handle-as-image</title>
4284 <term>Typical use:</term>
4286 <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>
4291 <term>Effect:</term>
4294 This action alone doesn't do anything noticeable. It just marks URLs as images.
4295 If the <literal><link linkend="block">block</link></literal> action <emphasis>also applies</emphasis>,
4296 the presence or absence of this mark decides whether an HTML <quote>blocked</quote>
4297 page, or a replacement image (as determined by the <literal><link
4298 linkend="set-image-blocker">set-image-blocker</link></literal> action) will be sent to the
4299 client as a substitute for the blocked content.
4306 <!-- Boolean, Parameterized, Multi-value -->
4308 <para>Boolean.</para>
4313 <term>Parameter:</term>
4325 The below generic example section is actually part of <filename>default.action</filename>.
4326 It marks all URLs with well-known image file name extensions as images and should
4330 Users will probably only want to use the handle-as-image action in conjunction with
4331 <literal><link linkend="block">block</link></literal>, to block sources of banners, whose URLs don't
4332 reflect the file type, like in the second example section.
4335 Note that you cannot treat HTML pages as images in most cases. For instance, (in-line) ad
4336 frames require an HTML page to be sent, or they won't display properly.
4337 Forcing <literal>handle-as-image</literal> in this situation will not replace the
4338 ad frame with an image, but lead to error messages.
4344 <term>Example usage (sections):</term>
4347 <screen># Generic image extensions:
4350 /.*\.(gif|jpg|jpeg|png|bmp|ico)$
4352 # These don't look like images, but they're banners and should be
4353 # blocked as images:
4355 {+block{Nasty banners.} +handle-as-image}
4356 nasty-banner-server.example.com/junk.cgi\?output=trash
4365 <!-- ~~~~~ New section ~~~~~ -->
4366 <sect3 renderas="sect4" id="hide-accept-language">
4367 <title>hide-accept-language</title>
4373 <term>Typical use:</term>
4375 <para>Pretend to use different language settings.</para>
4380 <term>Effect:</term>
4383 Deletes or replaces the <quote>Accept-Language:</quote> HTTP header in client requests.
4390 <!-- Boolean, Parameterized, Multi-value -->
4392 <para>Parameterized.</para>
4397 <term>Parameter:</term>
4400 Keyword: <quote>block</quote>, or any user defined value.
4409 Faking the browser's language settings can be useful to make a
4410 foreign User-Agent set with
4411 <literal><link linkend="hide-user-agent">hide-user-agent</link></literal>
4415 However some sites with content in different languages check the
4416 <quote>Accept-Language:</quote> to decide which one to take by default.
4417 Sometimes it isn't possible to later switch to another language without
4418 changing the <quote>Accept-Language:</quote> header first.
4421 Therefore it's a good idea to either only change the
4422 <quote>Accept-Language:</quote> header to languages you understand,
4423 or to languages that aren't wide spread.
4426 Before setting the <quote>Accept-Language:</quote> header
4427 to a rare language, you should consider that it helps to
4428 make your requests unique and thus easier to trace.
4429 If you don't plan to change this header frequently,
4430 you should stick to a common language.
4436 <term>Example usage (section):</term>
4439 <screen># Pretend to use Canadian language settings.
4440 {+hide-accept-language{en-ca} \
4441 +hide-user-agent{Mozilla/5.0 (X11; U; OpenBSD i386; en-CA; rv:1.8.0.4) Gecko/20060628 Firefox/1.5.0.4} \
4451 <!-- ~~~~~ New section ~~~~~ -->
4452 <sect3 renderas="sect4" id="hide-content-disposition">
4453 <title>hide-content-disposition</title>
4459 <term>Typical use:</term>
4461 <para>Prevent download menus for content you prefer to view inside the browser.</para>
4466 <term>Effect:</term>
4469 Deletes or replaces the <quote>Content-Disposition:</quote> HTTP header set by some servers.
4476 <!-- Boolean, Parameterized, Multi-value -->
4478 <para>Parameterized.</para>
4483 <term>Parameter:</term>
4486 Keyword: <quote>block</quote>, or any user defined value.
4495 Some servers set the <quote>Content-Disposition:</quote> HTTP header for
4496 documents they assume you want to save locally before viewing them.
4497 The <quote>Content-Disposition:</quote> header contains the file name
4498 the browser is supposed to use by default.
4501 In most browsers that understand this header, it makes it impossible to
4502 <emphasis>just view</emphasis> the document, without downloading it first,
4503 even if it's just a simple text file or an image.
4506 Removing the <quote>Content-Disposition:</quote> header helps
4507 to prevent this annoyance, but some browsers additionally check the
4508 <quote>Content-Type:</quote> header, before they decide if they can
4509 display a document without saving it first. In these cases, you have
4510 to change this header as well, before the browser stops displaying
4514 It is also possible to change the server's file name suggestion
4515 to another one, but in most cases it isn't worth the time to set
4519 This action will probably be removed in the future,
4520 use server-header filters instead.
4526 <term>Example usage:</term>
4529 <screen># Disarm the download link in Sourceforge's patch tracker
4531 +content-type-overwrite{text/plain}\
4532 +hide-content-disposition{block} }
4533 .sourceforge.net/tracker/download\.php</screen>
4541 <!-- ~~~~~ New section ~~~~~ -->
4542 <sect3 renderas="sect4" id="hide-if-modified-since">
4543 <title>hide-if-modified-since</title>
4549 <term>Typical use:</term>
4551 <para>Prevent yet another way to track the user's steps between sessions.</para>
4556 <term>Effect:</term>
4559 Deletes the <quote>If-Modified-Since:</quote> HTTP client header or modifies its value.
4566 <!-- Boolean, Parameterized, Multi-value -->
4568 <para>Parameterized.</para>
4573 <term>Parameter:</term>
4576 Keyword: <quote>block</quote>, or a user defined value that specifies a range of hours.
4585 Removing this header is useful for filter testing, where you want to force a real
4586 reload instead of getting status code <quote>304</quote>, which would cause the
4587 browser to use a cached copy of the page.
4590 Instead of removing the header, <literal>hide-if-modified-since</literal> can
4591 also add or subtract a random amount of time to/from the header's value.
4592 You specify a range of minutes where the random factor should be chosen from and
4593 <application>Privoxy</application> does the rest. A negative value means
4594 subtracting, a positive value adding.
4597 Randomizing the value of the <quote>If-Modified-Since:</quote> makes
4598 it less likely that the server can use the time as a cookie replacement,
4599 but you will run into caching problems if the random range is too high.
4602 It is a good idea to only use a small negative value and let
4603 <literal><link linkend="overwrite-last-modified">overwrite-last-modified</link></literal>
4604 handle the greater changes.
4607 It is also recommended to use this action together with
4608 <literal><link linkend="crunch-if-none-match">crunch-if-none-match</link></literal>,
4609 otherwise it's more or less pointless.
4615 <term>Example usage (section):</term>
4618 <screen># Let the browser revalidate but make tracking based on the time less likely.
4619 {+hide-if-modified-since{-60} \
4620 +overwrite-last-modified{randomize} \
4621 +crunch-if-none-match}
4630 <!-- ~~~~~ New section ~~~~~ -->
4631 <sect3 renderas="sect4" id="hide-from-header">
4632 <title>hide-from-header</title>
4636 <term>Typical use:</term>
4638 <para>Keep your (old and ill) browser from telling web servers your email address</para>
4643 <term>Effect:</term>
4646 Deletes any existing <quote>From:</quote> HTTP header, or replaces it with the
4654 <!-- Boolean, Parameterized, Multi-value -->
4656 <para>Parameterized.</para>
4661 <term>Parameter:</term>
4664 Keyword: <quote>block</quote>, or any user defined value.
4673 The keyword <quote>block</quote> will completely remove the header
4674 (not to be confused with the <literal><link linkend="block">block</link></literal>
4678 Alternately, you can specify any value you prefer to be sent to the web
4679 server. If you do, it is a matter of fairness not to use any address that
4680 is actually used by a real person.
4683 This action is rarely needed, as modern web browsers don't send
4684 <quote>From:</quote> headers anymore.
4690 <term>Example usage:</term>
4693 <screen>+hide-from-header{block}</screen> or
4694 <screen>+hide-from-header{spam-me-senseless@sittingduck.example.com}</screen>
4702 <!-- ~~~~~ New section ~~~~~ -->
4703 <sect3 renderas="sect4" id="hide-referrer">
4704 <title>hide-referrer</title>
4705 <anchor id="hide-referer">
4708 <term>Typical use:</term>
4710 <para>Conceal which link you followed to get to a particular site</para>
4715 <term>Effect:</term>
4718 Deletes the <quote>Referer:</quote> (sic) HTTP header from the client request,
4719 or replaces it with a forged one.
4726 <!-- Boolean, Parameterized, Multi-value -->
4728 <para>Parameterized.</para>
4733 <term>Parameter:</term>
4737 <para><quote>conditional-block</quote> to delete the header completely if the host has changed.</para>
4740 <para><quote>conditional-forge</quote> to forge the header if the host has changed.</para>
4743 <para><quote>block</quote> to delete the header unconditionally.</para>
4746 <para><quote>forge</quote> to pretend to be coming from the homepage of the server we are talking to.</para>
4749 <para>Any other string to set a user defined referrer.</para>
4759 <literal>conditional-block</literal> is the only parameter,
4760 that isn't easily detected in the server's log file. If it blocks the
4761 referrer, the request will look like the visitor used a bookmark or
4762 typed in the address directly.
4765 Leaving the referrer unmodified for requests on the same host
4766 allows the server owner to see the visitor's <quote>click path</quote>,
4767 but in most cases she could also get that information by comparing
4768 other parts of the log file: for example the User-Agent if it isn't
4769 a very common one, or the user's IP address if it doesn't change between
4773 Always blocking the referrer, or using a custom one, can lead to
4774 failures on servers that check the referrer before they answer any
4775 requests, in an attempt to prevent their content from being
4776 embedded or linked to elsewhere.
4779 Both <literal>conditional-block</literal> and <literal>forge</literal>
4780 will work with referrer checks, as long as content and valid referring page
4781 are on the same host. Most of the time that's the case.
4784 <literal>hide-referer</literal> is an alternate spelling of
4785 <literal>hide-referrer</literal> and the two can be can be freely
4786 substituted with each other. (<quote>referrer</quote> is the
4787 correct English spelling, however the HTTP specification has a bug - it
4788 requires it to be spelled as <quote>referer</quote>.)
4794 <term>Example usage:</term>
4797 <screen>+hide-referrer{forge}</screen> or
4798 <screen>+hide-referrer{http://www.yahoo.com/}</screen>
4806 <!-- ~~~~~ New section ~~~~~ -->
4807 <sect3 renderas="sect4" id="hide-user-agent">
4808 <title>hide-user-agent</title>
4812 <term>Typical use:</term>
4814 <para>Try to conceal your type of browser and client operating system</para>
4819 <term>Effect:</term>
4822 Replaces the value of the <quote>User-Agent:</quote> HTTP header
4823 in client requests with the specified value.
4830 <!-- Boolean, Parameterized, Multi-value -->
4832 <para>Parameterized.</para>
4837 <term>Parameter:</term>
4840 Any user-defined string.
4850 This can lead to problems on web sites that depend on looking at this header in
4851 order to customize their content for different browsers (which, by the
4852 way, is <emphasis>NOT</emphasis> the right thing to do: good web sites
4853 work browser-independently).
4857 Using this action in multi-user setups or wherever different types of
4858 browsers will access the same <application>Privoxy</application> is
4859 <emphasis>not recommended</emphasis>. In single-user, single-browser
4860 setups, you might use it to delete your OS version information from
4861 the headers, because it is an invitation to exploit known bugs for your
4862 OS. It is also occasionally useful to forge this in order to access
4863 sites that won't let you in otherwise (though there may be a good
4864 reason in some cases).
4867 More information on known user-agent strings can be found at
4868 <ulink url="http://www.user-agents.org/">http://www.user-agents.org/</ulink>
4870 <ulink url="http://en.wikipedia.org/wiki/User_agent">http://en.wikipedia.org/wiki/User_agent</ulink>.
4876 <term>Example usage:</term>
4879 <screen>+hide-user-agent{Netscape 6.1 (X11; I; Linux 2.4.18 i686)}</screen>
4887 <!-- ~~~~~ New section ~~~~~ -->
4888 <sect3 renderas="sect4" id="limit-connect">
4889 <title>limit-connect</title>
4893 <term>Typical use:</term>
4895 <para>Prevent abuse of <application>Privoxy</application> as a TCP proxy relay or disable SSL for untrusted sites</para>
4900 <term>Effect:</term>
4903 Specifies to which ports HTTP CONNECT requests are allowable.
4910 <!-- Boolean, Parameterized, Multi-value -->
4912 <para>Parameterized.</para>
4917 <term>Parameter:</term>
4920 A comma-separated list of ports or port ranges (the latter using dashes, with the minimum
4921 defaulting to 0 and the maximum to 65K).
4930 By default, i.e. if no <literal>limit-connect</literal> action applies,
4931 <application>Privoxy</application> allows HTTP CONNECT requests to all
4932 ports. Use <literal>limit-connect</literal> if fine-grained control
4933 is desired for some or all destinations.
4936 The CONNECT methods exists in HTTP to allow access to secure websites
4937 (<quote>https://</quote> URLs) through proxies. It works very simply:
4938 the proxy connects to the server on the specified port, and then
4939 short-circuits its connections to the client and to the remote server.
4940 This means CONNECT-enabled proxies can be used as TCP relays very easily.
4943 <application>Privoxy</application> relays HTTPS traffic without seeing
4944 the decoded content. Websites can leverage this limitation to circumvent &my-app;'s
4945 filters. By specifying an invalid port range you can disable HTTPS entirely.
4951 <term>Example usages:</term>
4953 <!-- I had trouble getting the spacing to look right in my browser -->
4954 <!-- I probably have the wrong font setup, bollocks. -->
4955 <!-- Apparently the emphasis tag uses a proportional font no matter what -->
4957 <screen>+limit-connect{443} # Port 443 is OK.
4958 +limit-connect{80,443} # Ports 80 and 443 are OK.
4959 +limit-connect{-3, 7, 20-100, 500-} # Ports less than 3, 7, 20 to 100 and above 500 are OK.
4960 +limit-connect{-} # All ports are OK
4961 +limit-connect{,} # No HTTPS/SSL traffic is allowed</screen>
4969 <!-- ~~~~~ New section ~~~~~ -->
4970 <sect3 renderas="sect4" id="limit-cookie-lifetime">
4971 <title>limit-cookie-lifetime</title>
4975 <term>Typical use:</term>
4977 <para>Limit the lifetime of HTTP cookies to a couple of minutes or hours.</para>
4982 <term>Effect:</term>
4985 Overwrites the expires field in Set-Cookie server headers if it's above the specified limit.
4992 <!-- Boolean, Parameterized, Multi-value -->
4994 <para>Parameterized.</para>
4999 <term>Parameter:</term>
5002 The lifetime limit in minutes, or 0.
5011 This action reduces the lifetime of HTTP cookies coming from the
5012 server to the specified number of minutes, starting from the time
5013 the cookie passes Privoxy.
5016 Cookies with a lifetime below the limit are not modified.
5017 The lifetime of session cookies is set to the specified limit.
5020 The effect of this action depends on the server.
5023 In case of servers which refresh their cookies with each response
5024 (or at least frequently), the lifetime limit set by this action
5026 Thus, a session associated with the cookie continues to work with
5027 this action enabled, as long as a new request is made before the
5028 last limit set is reached.
5031 However, some servers send their cookies once, with a lifetime of several
5032 years (the year 2037 is a popular choice), and do not refresh them
5033 until a certain event in the future, for example the user logging out.
5034 In this case this action may limit the absolute lifetime of the session,
5035 even if requests are made frequently.
5038 If the parameter is <quote>0</quote>, this action behaves like
5039 <literal><link linkend="session-cookies-only">session-cookies-only</link></literal>.
5045 <term>Example usages:</term>
5048 <screen>+limit-cookie-lifetime{60}
5056 <!-- ~~~~~ New section ~~~~~ -->
5057 <sect3 renderas="sect4" id="prevent-compression">
5058 <title>prevent-compression</title>
5062 <term>Typical use:</term>
5065 Ensure that servers send the content uncompressed, so it can be
5066 passed through <literal><link linkend="filter">filter</link></literal>s.
5072 <term>Effect:</term>
5075 Removes the Accept-Encoding header which can be used to ask for compressed transfer.
5082 <!-- Boolean, Parameterized, Multi-value -->
5084 <para>Boolean.</para>
5089 <term>Parameter:</term>
5101 More and more websites send their content compressed by default, which
5102 is generally a good idea and saves bandwidth. But the <literal><link
5103 linkend="filter">filter</link></literal> and
5104 <literal><link linkend="deanimate-gifs">deanimate-gifs</link></literal>
5105 actions need access to the uncompressed data.
5108 When compiled with zlib support (available since &my-app; 3.0.7), content that should be
5109 filtered is decompressed on-the-fly and you don't have to worry about this action.
5110 If you are using an older &my-app; version, or one that hasn't been compiled with zlib
5111 support, this action can be used to convince the server to send the content uncompressed.
5114 Most text-based instances compress very well, the size is seldom decreased by less than 50%,
5115 for markup-heavy instances like news feeds saving more than 90% of the original size isn't
5119 Not using compression will therefore slow down the transfer, and you should only
5120 enable this action if you really need it. As of &my-app; 3.0.7 it's disabled in all
5121 predefined action settings.
5124 Note that some (rare) ill-configured sites don't handle requests for uncompressed
5125 documents correctly. Broken PHP applications tend to send an empty document body,
5126 some IIS versions only send the beginning of the content. If you enable
5127 <literal>prevent-compression</literal> per default, you might want to add
5128 exceptions for those sites. See the example for how to do that.
5134 <term>Example usage (sections):</term>
5138 # Selectively turn off compression, and enable a filter
5140 { +filter{tiny-textforms} +prevent-compression }
5141 # Match only these sites
5146 # Or instead, we could set a universal default:
5148 { +prevent-compression }
5151 # Then maybe make exceptions for broken sites:
5153 { -prevent-compression }
5154 .compusa.com/</screen>
5163 <!-- ~~~~~ New section ~~~~~ -->
5164 <sect3 renderas="sect4" id="overwrite-last-modified">
5165 <title>overwrite-last-modified</title>
5171 <term>Typical use:</term>
5173 <para>Prevent yet another way to track the user's steps between sessions.</para>
5178 <term>Effect:</term>
5181 Deletes the <quote>Last-Modified:</quote> HTTP server header or modifies its value.
5188 <!-- Boolean, Parameterized, Multi-value -->
5190 <para>Parameterized.</para>
5195 <term>Parameter:</term>
5198 One of the keywords: <quote>block</quote>, <quote>reset-to-request-time</quote>
5199 and <quote>randomize</quote>
5208 Removing the <quote>Last-Modified:</quote> header is useful for filter
5209 testing, where you want to force a real reload instead of getting status
5210 code <quote>304</quote>, which would cause the browser to reuse the old
5211 version of the page.
5214 The <quote>randomize</quote> option overwrites the value of the
5215 <quote>Last-Modified:</quote> header with a randomly chosen time
5216 between the original value and the current time. In theory the server
5217 could send each document with a different <quote>Last-Modified:</quote>
5218 header to track visits without using cookies. <quote>Randomize</quote>
5219 makes it impossible and the browser can still revalidate cached documents.
5222 <quote>reset-to-request-time</quote> overwrites the value of the
5223 <quote>Last-Modified:</quote> header with the current time. You could use
5224 this option together with
5225 <literal><link linkend="hide-if-modified-since">hide-if-modified-since</link></literal>
5226 to further customize your random range.
5229 The preferred parameter here is <quote>randomize</quote>. It is safe
5230 to use, as long as the time settings are more or less correct.
5231 If the server sets the <quote>Last-Modified:</quote> header to the time
5232 of the request, the random range becomes zero and the value stays the same.
5233 Therefore you should later randomize it a second time with
5234 <literal><link linkend="hide-if-modified-since">hided-if-modified-since</link></literal>,
5238 It is also recommended to use this action together with
5239 <literal><link linkend="crunch-if-none-match">crunch-if-none-match</link></literal>.
5245 <term>Example usage:</term>
5248 <screen># Let the browser revalidate without being tracked across sessions
5249 { +hide-if-modified-since{-60} \
5250 +overwrite-last-modified{randomize} \
5251 +crunch-if-none-match}
5260 <!-- ~~~~~ New section ~~~~~ -->
5261 <sect3 renderas="sect4" id="redirect">
5262 <title>redirect</title>
5268 <term>Typical use:</term>
5271 Redirect requests to other sites.
5277 <term>Effect:</term>
5280 Convinces the browser that the requested document has been moved
5281 to another location and the browser should get it from there.
5288 <!-- Boolean, Parameterized, Multi-value -->
5290 <para>Parameterized</para>
5295 <term>Parameter:</term>
5298 An absolute URL or a single pcrs command.
5307 Requests to which this action applies are answered with a
5308 HTTP redirect to URLs of your choosing. The new URL is
5309 either provided as parameter, or derived by applying a
5310 single pcrs command to the original URL.
5313 The syntax for pcrs commands is documented in the
5314 <link linkend="filter-file">filter file</link> section.
5317 This action will be ignored if you use it together with
5318 <literal><link linkend="block">block</link></literal>.
5319 It can be combined with
5320 <literal><link linkend="fast-redirects">fast-redirects{check-decoded-url}</link></literal>
5321 to redirect to a decoded version of a rewritten URL.
5324 Use this action carefully, make sure not to create redirection loops
5325 and be aware that using your own redirects might make it
5326 possible to fingerprint your requests.
5329 In case of problems with your redirects, or simply to watch
5330 them working, enable <link linkend="DEBUG">debug 128</link>.
5336 <term>Example usages:</term>
5339 <screen># Replace example.com's style sheet with another one
5340 { +redirect{http://localhost/css-replacements/example.com.css} }
5341 example.com/stylesheet\.css
5343 # Create a short, easy to remember nickname for a favorite site
5344 # (relies on the browser accept and forward invalid URLs to &my-app;)
5345 { +redirect{http://www.privoxy.org/user-manual/actions-file.html} }
5348 # Always use the expanded view for Undeadly.org articles
5349 # (Note the $ at the end of the URL pattern to make sure
5350 # the request for the rewritten URL isn't redirected as well)
5351 {+redirect{s@$@&mode=expanded@}}
5352 undeadly.org/cgi\?action=article&sid=\d*$
5354 # Redirect Google search requests to MSN
5355 {+redirect{s@^http://[^/]*/search\?q=([^&]*).*@http://search.msn.com/results.aspx?q=$1@}}
5358 # Redirect MSN search requests to Yahoo
5359 {+redirect{s@^http://[^/]*/results\.aspx\?q=([^&]*).*@http://search.yahoo.com/search?p=$1@}}
5360 search.msn.com//results\.aspx\?q=
5362 # Redirect remote requests for this manual
5363 # to the local version delivered by Privoxy
5364 {+redirect{s@^http://www@http://config@}}
5365 www.privoxy.org/user-manual/</screen>
5374 <!-- ~~~~~ New section ~~~~~ -->
5375 <sect3 renderas="sect4" id="server-header-filter">
5376 <title>server-header-filter</title>
5380 <term>Typical use:</term>
5383 Rewrite or remove single server headers.
5389 <term>Effect:</term>
5392 All server headers to which this action applies are filtered on-the-fly
5393 through the specified regular expression based substitutions.
5400 <!-- boolean, parameterized, Multi-value -->
5402 <para>Parameterized.</para>
5407 <term>Parameter:</term>
5410 The name of a server-header filter, as defined in one of the
5411 <link linkend="filter-file">filter files</link>.
5420 Server-header filters are applied to each header on its own, not to
5421 all at once. This makes it easier to diagnose problems, but on the downside
5422 you can't write filters that only change header x if header y's value is z.
5423 You can do that by using tags though.
5426 Server-header filters are executed after the other header actions have finished
5427 and use their output as input.
5430 Please refer to the <link linkend="filter-file">filter file chapter</link>
5431 to learn which server-header filters are available by default, and how to
5438 <term>Example usage (section):</term>
5442 {+server-header-filter{html-to-xml}}
5443 example.org/xml-instance-that-is-delivered-as-html
5445 {+server-header-filter{xml-to-html}}
5446 example.org/instance-that-is-delivered-as-xml-but-is-not
5456 <!-- ~~~~~ New section ~~~~~ -->
5457 <sect3 renderas="sect4" id="server-header-tagger">
5458 <title>server-header-tagger</title>
5462 <term>Typical use:</term>
5465 Enable or disable filters based on the Content-Type header.
5471 <term>Effect:</term>
5474 Server headers to which this action applies are filtered on-the-fly through
5475 the specified regular expression based substitutions, the result is used as
5483 <!-- boolean, parameterized, Multi-value -->
5485 <para>Parameterized.</para>
5490 <term>Parameter:</term>
5493 The name of a server-header tagger, as defined in one of the
5494 <link linkend="filter-file">filter files</link>.
5503 Server-header taggers are applied to each header on its own,
5504 and as the header isn't modified, each tagger <quote>sees</quote>
5508 Server-header taggers are executed before all other header actions
5509 that modify server headers. Their tags can be used to control
5510 all of the other server-header actions, the content filters
5511 and the crunch actions (<link linkend="redirect">redirect</link>
5512 and <link linkend="block">block</link>).
5515 Obviously crunching based on tags created by server-header taggers
5516 doesn't prevent the request from showing up in the server's log file.
5523 <term>Example usage (section):</term>
5527 # Tag every request with the content type declared by the server
5528 {+server-header-tagger{content-type}}
5539 <!-- ~~~~~ New section ~~~~~ -->
5540 <sect3 renderas="sect4" id="session-cookies-only">
5541 <title>session-cookies-only</title>
5545 <term>Typical use:</term>
5548 Allow only temporary <quote>session</quote> cookies (for the current
5549 browser session <emphasis>only</emphasis>).
5555 <term>Effect:</term>
5558 Deletes the <quote>expires</quote> field from <quote>Set-Cookie:</quote>
5559 server headers. Most browsers will not store such cookies permanently and
5560 forget them in between sessions.
5567 <!-- Boolean, Parameterized, Multi-value -->
5569 <para>Boolean.</para>
5574 <term>Parameter:</term>
5586 This is less strict than <literal><link linkend="crunch-incoming-cookies">crunch-incoming-cookies</link></literal> /
5587 <literal><link linkend="crunch-outgoing-cookies">crunch-outgoing-cookies</link></literal> and allows you to browse
5588 websites that insist or rely on setting cookies, without compromising your privacy too badly.
5591 Most browsers will not permanently store cookies that have been processed by
5592 <literal>session-cookies-only</literal> and will forget about them between sessions.
5593 This makes profiling cookies useless, but won't break sites which require cookies so
5594 that you can log in for transactions. This is generally turned on for all
5595 sites, and is the recommended setting.
5598 It makes <emphasis>no sense at all</emphasis> to use <literal>session-cookies-only</literal>
5599 together with <literal><link linkend="crunch-incoming-cookies">crunch-incoming-cookies</link></literal> or
5600 <literal><link linkend="crunch-outgoing-cookies">crunch-outgoing-cookies</link></literal>. If you do, cookies
5601 will be plainly killed.
5604 Note that it is up to the browser how it handles such cookies without an <quote>expires</quote>
5605 field. If you use an exotic browser, you might want to try it out to be sure.
5608 This setting also has no effect on cookies that may have been stored
5609 previously by the browser before starting <application>Privoxy</application>.
5610 These would have to be removed manually.
5613 <application>Privoxy</application> also uses
5614 the <link linkend="filter-content-cookies">content-cookies filter</link>
5615 to block some types of cookies. Content cookies are not effected by
5616 <literal>session-cookies-only</literal>.
5622 <term>Example usage:</term>
5625 <screen>+session-cookies-only</screen>
5633 <!-- ~~~~~ New section ~~~~~ -->
5634 <sect3 renderas="sect4" id="set-image-blocker">
5635 <title>set-image-blocker</title>
5639 <term>Typical use:</term>
5641 <para>Choose the replacement for blocked images</para>
5646 <term>Effect:</term>
5649 This action alone doesn't do anything noticeable. If <emphasis>both</emphasis>
5650 <literal><link linkend="block">block</link></literal> <emphasis>and</emphasis> <literal><link
5651 linkend="handle-as-image">handle-as-image</link></literal> <emphasis>also</emphasis>
5652 apply, i.e. if the request is to be blocked as an image,
5653 <emphasis>then</emphasis> the parameter of this action decides what will be
5654 sent as a replacement.
5661 <!-- Boolean, Parameterized, Multi-value -->
5663 <para>Parameterized.</para>
5668 <term>Parameter:</term>
5673 <quote>pattern</quote> to send a built-in checkerboard pattern image. The image is visually
5674 decent, scales very well, and makes it obvious where banners were busted.
5679 <quote>blank</quote> to send a built-in transparent image. This makes banners disappear
5680 completely, but makes it hard to detect where <application>Privoxy</application> has blocked
5681 images on a given page and complicates troubleshooting if <application>Privoxy</application>
5682 has blocked innocent images, like navigation icons.
5687 <quote><replaceable class="parameter">target-url</replaceable></quote> to
5688 send a redirect to <replaceable class="parameter">target-url</replaceable>. You can redirect
5689 to any image anywhere, even in your local filesystem via <quote>file:///</quote> URL.
5690 (But note that not all browsers support redirecting to a local file system).
5693 A good application of redirects is to use special <application>Privoxy</application>-built-in
5694 URLs, which send the built-in images, as <replaceable class="parameter">target-url</replaceable>.
5695 This has the same visual effect as specifying <quote>blank</quote> or <quote>pattern</quote> in
5696 the first place, but enables your browser to cache the replacement image, instead of requesting
5697 it over and over again.
5708 The URLs for the built-in images are <quote>http://config.privoxy.org/send-banner?type=<replaceable
5709 class="parameter">type</replaceable></quote>, where <replaceable class="parameter">type</replaceable> is
5710 either <quote>blank</quote> or <quote>pattern</quote>.
5713 There is a third (advanced) type, called <quote>auto</quote>. It is <emphasis>NOT</emphasis> to be
5714 used in <literal>set-image-blocker</literal>, but meant for use from <link linkend="filter-file">filters</link>.
5715 Auto will select the type of image that would have applied to the referring page, had it been an image.
5721 <term>Example usage:</term>
5727 <screen>+set-image-blocker{pattern}</screen>
5730 Redirect to the BSD daemon:
5733 <screen>+set-image-blocker{http://www.freebsd.org/gifs/dae_up3.gif}</screen>
5736 Redirect to the built-in pattern for better caching:
5739 <screen>+set-image-blocker{http://config.privoxy.org/send-banner?type=pattern}</screen>
5747 <!-- ~~~~~ New section ~~~~~ -->
5749 <title>Summary</title>
5751 Note that many of these actions have the potential to cause a page to
5752 misbehave, possibly even not to display at all. There are many ways
5753 a site designer may choose to design his site, and what HTTP header
5754 content, and other criteria, he may depend on. There is no way to have hard
5755 and fast rules for all sites. See the <link
5756 linkend="ACTIONSANAT">Appendix</link> for a brief example on troubleshooting
5762 <!-- ~~~~~ New section ~~~~~ -->
5763 <sect2 id="aliases">
5764 <title>Aliases</title>
5766 Custom <quote>actions</quote>, known to <application>Privoxy</application>
5767 as <quote>aliases</quote>, can be defined by combining other actions.
5768 These can in turn be invoked just like the built-in actions.
5769 Currently, an alias name can contain any character except space, tab,
5771 <quote>{</quote> and <quote>}</quote>, but we <emphasis>strongly
5772 recommend</emphasis> that you only use <quote>a</quote> to <quote>z</quote>,
5773 <quote>0</quote> to <quote>9</quote>, <quote>+</quote>, and <quote>-</quote>.
5774 Alias names are not case sensitive, and are not required to start with a
5775 <quote>+</quote> or <quote>-</quote> sign, since they are merely textually
5779 Aliases can be used throughout the actions file, but they <emphasis>must be
5780 defined in a special section at the top of the file!</emphasis>
5781 And there can only be one such section per actions file. Each actions file may
5782 have its own alias section, and the aliases defined in it are only visible
5786 There are two main reasons to use aliases: One is to save typing for frequently
5787 used combinations of actions, the other one is a gain in flexibility: If you
5788 decide once how you want to handle shops by defining an alias called
5789 <quote>shop</quote>, you can later change your policy on shops in
5790 <emphasis>one</emphasis> place, and your changes will take effect everywhere
5791 in the actions file where the <quote>shop</quote> alias is used. Calling aliases
5792 by their purpose also makes your actions files more readable.
5795 Currently, there is one big drawback to using aliases, though:
5796 <application>Privoxy</application>'s built-in web-based action file
5797 editor honors aliases when reading the actions files, but it expands
5798 them before writing. So the effects of your aliases are of course preserved,
5799 but the aliases themselves are lost when you edit sections that use aliases
5804 Now let's define some aliases...
5809 # Useful custom aliases we can use later.
5811 # Note the (required!) section header line and that this section
5812 # must be at the top of the actions file!
5816 # These aliases just save typing later:
5817 # (Note that some already use other aliases!)
5819 +crunch-all-cookies = +<link linkend="CRUNCH-INCOMING-COOKIES">crunch-incoming-cookies</link> +<link linkend="CRUNCH-OUTGOING-COOKIES">crunch-outgoing-cookies</link>
5820 -crunch-all-cookies = -<link linkend="CRUNCH-INCOMING-COOKIES">crunch-incoming-cookies</link> -<link linkend="CRUNCH-OUTGOING-COOKIES">crunch-outgoing-cookies</link>
5821 +block-as-image = +block{Blocked image.} +handle-as-image
5822 allow-all-cookies = -crunch-all-cookies -<link linkend="SESSION-COOKIES-ONLY">session-cookies-only</link> -<link linkend="FILTER-CONTENT-COOKIES">filter{content-cookies}</link>
5824 # These aliases define combinations of actions
5825 # that are useful for certain types of sites:
5827 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>
5829 shop = -crunch-all-cookies -<link linkend="FILTER-ALL-POPUPS">filter{all-popups}</link>
5831 # Short names for other aliases, for really lazy people ;-)
5833 c0 = +crunch-all-cookies
5834 c1 = -crunch-all-cookies</screen>
5838 ...and put them to use. These sections would appear in the lower part of an
5839 actions file and define exceptions to the default actions (as specified further
5840 up for the <quote>/</quote> pattern):
5845 # These sites are either very complex or very keen on
5846 # user data and require minimal interference to work:
5849 .office.microsoft.com
5850 .windowsupdate.microsoft.com
5851 # Gmail is really mail.google.com, not gmail.com
5855 # Allow cookies (for setting and retrieving your customer data)
5859 .worldpay.com # for quietpc.com
5862 # These shops require pop-ups:
5864 {-filter{all-popups} -filter{unsolicited-popups}}
5866 .overclockers.co.uk</screen>
5870 Aliases like <quote>shop</quote> and <quote>fragile</quote> are typically used for
5871 <quote>problem</quote> sites that require more than one action to be disabled
5872 in order to function properly.
5878 <!-- ~~~~~ New section ~~~~~ -->
5879 <sect2 id="act-examples">
5880 <title>Actions Files Tutorial</title>
5882 The above chapters have shown <link linkend="actions-file">which actions files
5883 there are and how they are organized</link>, how actions are <link
5884 linkend="actions">specified</link> and <link linkend="actions-apply">applied
5885 to URLs</link>, how <link linkend="af-patterns">patterns</link> work, and how to
5886 define and use <link linkend="aliases">aliases</link>. Now, let's look at an
5887 example <filename>match-all.action</filename>, <filename>default.action</filename>
5888 and <filename>user.action</filename> file and see how all these pieces come together:
5892 <title>match-all.action</title>
5894 Remember <emphasis>all actions are disabled when matching starts</emphasis>,
5895 so we have to explicitly enable the ones we want.
5899 While the <filename>match-all.action</filename> file only contains a
5900 single section, it is probably the most important one. It has only one
5901 pattern, <quote><literal>/</literal></quote>, but this pattern
5902 <link linkend="af-patterns">matches all URLs</link>. Therefore, the set of
5903 actions used in this <quote>default</quote> section <emphasis>will
5904 be applied to all requests as a start</emphasis>. It can be partly or
5905 wholly overridden by other actions files like <filename>default.action</filename>
5906 and <filename>user.action</filename>, but it will still be largely responsible
5907 for your overall browsing experience.
5911 Again, at the start of matching, all actions are disabled, so there is
5912 no need to disable any actions here. (Remember: a <quote>+</quote>
5913 preceding the action name enables the action, a <quote>-</quote> disables!).
5914 Also note how this long line has been made more readable by splitting it into
5915 multiple lines with line continuation.
5921 +<link linkend="CHANGE-X-FORWARDED-FOR">change-x-forwarded-for{block}</link> \
5922 +<link linkend="HIDE-FROM-HEADER">hide-from-header{block}</link> \
5923 +<link linkend="SET-IMAGE-BLOCKER">set-image-blocker{pattern}</link> \
5930 The default behavior is now set.
5935 <title>default.action</title>
5938 If you aren't a developer, there's no need for you to edit the
5939 <filename>default.action</filename> file. It is maintained by
5940 the &my-app; developers and if you disagree with some of the
5941 sections, you should overrule them in your <filename>user.action</filename>.
5945 Understanding the <filename>default.action</filename> file can
5946 help you with your <filename>user.action</filename>, though.
5950 The first section in this file is a special section for internal use
5951 that prevents older &my-app; versions from reading the file:
5956 ##########################################################################
5957 # Settings -- Don't change! For internal Privoxy use ONLY.
5958 ##########################################################################
5960 for-privoxy-version=3.0.11</screen>
5964 After that comes the (optional) alias section. We'll use the example
5965 section from the above <link linkend="aliases">chapter on aliases</link>,
5966 that also explains why and how aliases are used:
5971 ##########################################################################
5973 ##########################################################################
5976 # These aliases just save typing later:
5977 # (Note that some already use other aliases!)
5979 +crunch-all-cookies = +<link linkend="CRUNCH-INCOMING-COOKIES">crunch-incoming-cookies</link> +<link linkend="CRUNCH-OUTGOING-COOKIES">crunch-outgoing-cookies</link>
5980 -crunch-all-cookies = -<link linkend="CRUNCH-INCOMING-COOKIES">crunch-incoming-cookies</link> -<link linkend="CRUNCH-OUTGOING-COOKIES">crunch-outgoing-cookies</link>
5981 +block-as-image = +block{Blocked image.} +handle-as-image
5982 mercy-for-cookies = -crunch-all-cookies -<link linkend="SESSION-COOKIES-ONLY">session-cookies-only</link> -<link linkend="FILTER-CONTENT-COOKIES">filter{content-cookies}</link>
5984 # These aliases define combinations of actions
5985 # that are useful for certain types of sites:
5987 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>
5988 shop = -crunch-all-cookies -<link linkend="FILTER-ALL-POPUPS">filter{all-popups}</link></screen>
5992 The first of our specialized sections is concerned with <quote>fragile</quote>
5993 sites, i.e. sites that require minimum interference, because they are either
5994 very complex or very keen on tracking you (and have mechanisms in place that
5995 make them unusable for people who avoid being tracked). We will simply use
5996 our pre-defined <literal>fragile</literal> alias instead of stating the list
5997 of actions explicitly:
6002 ##########################################################################
6003 # Exceptions for sites that'll break under the default action set:
6004 ##########################################################################
6006 # "Fragile" Use a minimum set of actions for these sites (see alias above):
6009 .office.microsoft.com # surprise, surprise!
6010 .windowsupdate.microsoft.com
6011 mail.google.com</screen>
6015 Shopping sites are not as fragile, but they typically
6016 require cookies to log in, and pop-up windows for shopping
6017 carts or item details. Again, we'll use a pre-defined alias:
6026 .worldpay.com # for quietpc.com
6028 .scan.co.uk</screen>
6032 The <literal><link linkend="FAST-REDIRECTS">fast-redirects</link></literal>
6033 action, which may have been enabled in <filename>match-all.action</filename>,
6034 breaks some sites. So disable it for popular sites where we know it misbehaves:
6039 { -<link linkend="FAST-REDIRECTS">fast-redirects</link> }
6043 .altavista.com/.*(like|url|link):http
6044 .altavista.com/trans.*urltext=http
6045 .nytimes.com</screen>
6049 It is important that <application>Privoxy</application> knows which
6050 URLs belong to images, so that <emphasis>if</emphasis> they are to
6051 be blocked, a substitute image can be sent, rather than an HTML page.
6052 Contacting the remote site to find out is not an option, since it
6053 would destroy the loading time advantage of banner blocking, and it
6054 would feed the advertisers information about you. We can mark any
6055 URL as an image with the <literal><link
6056 linkend="handle-as-image">handle-as-image</link></literal> action,
6057 and marking all URLs that end in a known image file extension is a
6063 ##########################################################################
6065 ##########################################################################
6067 # Define which file types will be treated as images, in case they get
6068 # blocked further down this file:
6070 { +<link linkend="HANDLE-AS-IMAGE">handle-as-image</link> }
6071 /.*\.(gif|jpe?g|png|bmp|ico)$</screen>
6075 And then there are known banner sources. They often use scripts to
6076 generate the banners, so it won't be visible from the URL that the
6077 request is for an image. Hence we block them <emphasis>and</emphasis>
6078 mark them as images in one go, with the help of our
6079 <literal>+block-as-image</literal> alias defined above. (We could of
6080 course just as well use <literal>+<link linkend="block">block</link>
6081 +<link linkend="handle-as-image">handle-as-image</link></literal> here.)
6082 Remember that the type of the replacement image is chosen by the
6083 <literal><link linkend="set-image-blocker">set-image-blocker</link></literal>
6084 action. Since all URLs have matched the default section with its
6085 <literal>+<link linkend="set-image-blocker">set-image-blocker</link>{pattern}</literal>
6086 action before, it still applies and needn't be repeated:
6091 # Known ad generators:
6096 .ad.*.doubleclick.net
6097 .a.yimg.com/(?:(?!/i/).)*$
6098 .a[0-9].yimg.com/(?:(?!/i/).)*$
6104 One of the most important jobs of <application>Privoxy</application>
6105 is to block banners. Many of these can be <quote>blocked</quote>
6106 by the <literal><link linkend="filter">filter</link>{banners-by-size}</literal>
6107 action, which we enabled above, and which deletes the references to banner
6108 images from the pages while they are loaded, so the browser doesn't request
6109 them anymore, and hence they don't need to be blocked here. But this naturally
6110 doesn't catch all banners, and some people choose not to use filters, so we
6111 need a comprehensive list of patterns for banner URLs here, and apply the
6112 <literal><link linkend="block">block</link></literal> action to them.
6115 First comes many generic patterns, which do most of the work, by
6116 matching typical domain and path name components of banners. Then comes
6117 a list of individual patterns for specific sites, which is omitted here
6118 to keep the example short:
6123 ##########################################################################
6124 # Block these fine banners:
6125 ##########################################################################
6126 { <link linkend="BLOCK">+block{Banner ads.}</link> }
6134 /.*count(er)?\.(pl|cgi|exe|dll|asp|php[34]?)
6135 /(?:.*/)?(publicite|werbung|rekla(ma|me|am)|annonse|maino(kset|nta|s)?)/
6137 # Site-specific patterns (abbreviated):
6139 .hitbox.com</screen>
6143 It's quite remarkable how many advertisers actually call their banner
6144 servers ads.<replaceable>company</replaceable>.com, or call the directory
6145 in which the banners are stored simply <quote>banners</quote>. So the above
6146 generic patterns are surprisingly effective.
6149 But being very generic, they necessarily also catch URLs that we don't want
6150 to block. The pattern <literal>.*ads.</literal> e.g. catches
6151 <quote>nasty-<emphasis>ads</emphasis>.nasty-corp.com</quote> as intended,
6152 but also <quote>downlo<emphasis>ads</emphasis>.sourcefroge.net</quote> or
6153 <quote><emphasis>ads</emphasis>l.some-provider.net.</quote> So here come some
6154 well-known exceptions to the <literal>+<link linkend="BLOCK">block</link></literal>
6158 Note that these are exceptions to exceptions from the default! Consider the URL
6159 <quote>downloads.sourcefroge.net</quote>: Initially, all actions are deactivated,
6160 so it wouldn't get blocked. Then comes the defaults section, which matches the
6161 URL, but just deactivates the <literal><link linkend="BLOCK">block</link></literal>
6162 action once again. Then it matches <literal>.*ads.</literal>, an exception to the
6163 general non-blocking policy, and suddenly
6164 <literal><link linkend="BLOCK">+block</link></literal> applies. And now, it'll match
6165 <literal>.*loads.</literal>, where <literal><link linkend="BLOCK">-block</link></literal>
6166 applies, so (unless it matches <emphasis>again</emphasis> further down) it ends up
6167 with no <literal><link linkend="BLOCK">block</link></literal> action applying.
6172 ##########################################################################
6173 # Save some innocent victims of the above generic block patterns:
6174 ##########################################################################
6178 { -<link linkend="BLOCK">block</link> }
6179 adv[io]*. # (for advogato.org and advice.*)
6180 adsl. # (has nothing to do with ads)
6181 adobe. # (has nothing to do with ads either)
6182 ad[ud]*. # (adult.* and add.*)
6183 .edu # (universities don't host banners (yet!))
6184 .*loads. # (downloads, uploads etc)
6192 www.globalintersec.com/adv # (adv = advanced)
6193 www.ugu.com/sui/ugu/adv</screen>
6197 Filtering source code can have nasty side effects,
6198 so make an exception for our friends at sourceforge.net,
6199 and all paths with <quote>cvs</quote> in them. Note that
6200 <literal>-<link linkend="FILTER">filter</link></literal>
6201 disables <emphasis>all</emphasis> filters in one fell swoop!
6206 # Don't filter code!
6208 { -<link linkend="FILTER">filter</link> }
6213 .sourceforge.net</screen>
6217 The actual <filename>default.action</filename> is of course much more
6218 comprehensive, but we hope this example made clear how it works.
6223 <sect3><title>user.action</title>
6226 So far we are painting with a broad brush by setting general policies,
6227 which would be a reasonable starting point for many people. Now,
6228 you might want to be more specific and have customized rules that
6229 are more suitable to your personal habits and preferences. These would
6230 be for narrowly defined situations like your ISP or your bank, and should
6231 be placed in <filename>user.action</filename>, which is parsed after all other
6232 actions files and hence has the last word, over-riding any previously
6233 defined actions. <filename>user.action</filename> is also a
6234 <emphasis>safe</emphasis> place for your personal settings, since
6235 <filename>default.action</filename> is actively maintained by the
6236 <application>Privoxy</application> developers and you'll probably want
6237 to install updated versions from time to time.
6241 So let's look at a few examples of things that one might typically do in
6242 <filename>user.action</filename>:
6246 <!-- brief sample user.action here -->
6250 # My user.action file. <fred@example.com></screen>
6254 As <link linkend="aliases">aliases</link> are local to the actions
6255 file that they are defined in, you can't use the ones from
6256 <filename>default.action</filename>, unless you repeat them here:
6261 # Aliases are local to the file they are defined in.
6262 # (Re-)define aliases for this file:
6266 # These aliases just save typing later, and the alias names should
6267 # be self explanatory.
6269 +crunch-all-cookies = +crunch-incoming-cookies +crunch-outgoing-cookies
6270 -crunch-all-cookies = -crunch-incoming-cookies -crunch-outgoing-cookies
6271 allow-all-cookies = -crunch-all-cookies -session-cookies-only
6272 allow-popups = -filter{all-popups}
6273 +block-as-image = +block{Blocked as image.} +handle-as-image
6274 -block-as-image = -block
6276 # These aliases define combinations of actions that are useful for
6277 # certain types of sites:
6279 fragile = -block -crunch-all-cookies -filter -fast-redirects -hide-referrer
6280 shop = -crunch-all-cookies allow-popups
6282 # Allow ads for selected useful free sites:
6284 allow-ads = -block -filter{banners-by-size} -filter{banners-by-link}
6286 # Alias for specific file types that are text, but might have conflicting
6287 # MIME types. We want the browser to force these to be text documents.
6288 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>
6293 Say you have accounts on some sites that you visit regularly, and
6294 you don't want to have to log in manually each time. So you'd like
6295 to allow persistent cookies for these sites. The
6296 <literal>allow-all-cookies</literal> alias defined above does exactly
6297 that, i.e. it disables crunching of cookies in any direction, and the
6298 processing of cookies to make them only temporary.
6303 { allow-all-cookies }
6307 .redhat.com</screen>
6311 Your bank is allergic to some filter, but you don't know which, so you disable them all:
6316 { -<link linkend="FILTER">filter</link> }
6317 .your-home-banking-site.com</screen>
6321 Some file types you may not want to filter for various reasons:
6326 # Technical documentation is likely to contain strings that might
6327 # erroneously get altered by the JavaScript-oriented filters:
6332 # And this stupid host sends streaming video with a wrong MIME type,
6333 # so that Privoxy thinks it is getting HTML and starts filtering:
6335 stupid-server.example.com/</screen>
6339 Example of a simple <link linkend="BLOCK">block</link> action. Say you've
6340 seen an ad on your favourite page on example.com that you want to get rid of.
6341 You have right-clicked the image, selected <quote>copy image location</quote>
6342 and pasted the URL below while removing the leading http://, into a
6343 <literal>{ +block{} }</literal> section. Note that <literal>{ +handle-as-image
6344 }</literal> need not be specified, since all URLs ending in
6345 <literal>.gif</literal> will be tagged as images by the general rules as set
6346 in default.action anyway:
6351 { +<link linkend="BLOCK">block</link>{Nasty ads.} }
6352 www.example.com/nasty-ads/sponsor\.gif
6353 another.example.net/more/junk/here/</screen>
6357 The URLs of dynamically generated banners, especially from large banner
6358 farms, often don't use the well-known image file name extensions, which
6359 makes it impossible for <application>Privoxy</application> to guess
6360 the file type just by looking at the URL.
6361 You can use the <literal>+block-as-image</literal> alias defined above for
6363 Note that objects which match this rule but then turn out NOT to be an
6364 image are typically rendered as a <quote>broken image</quote> icon by the
6365 browser. Use cautiously.
6374 ar.atwola.com/</screen>
6378 Now you noticed that the default configuration breaks Forbes Magazine,
6379 but you were too lazy to find out which action is the culprit, and you
6380 were again too lazy to give <link linkend="contact">feedback</link>, so
6381 you just used the <literal>fragile</literal> alias on the site, and
6382 -- <emphasis>whoa!</emphasis> -- it worked. The <literal>fragile</literal>
6383 aliases disables those actions that are most likely to break a site. Also,
6384 good for testing purposes to see if it is <application>Privoxy</application>
6385 that is causing the problem or not. We later find other regular sites
6386 that misbehave, and add those to our personalized list of troublemakers:
6394 .mybank.com</screen>
6398 You like the <quote>fun</quote> text replacements in <filename>default.filter</filename>,
6399 but it is disabled in the distributed actions file.
6400 So you'd like to turn it on in your private,
6401 update-safe config, once and for all:
6406 { +<link linkend="filter-fun">filter{fun}</link> }
6407 / # For ALL sites!</screen>
6411 Note that the above is not really a good idea: There are exceptions
6412 to the filters in <filename>default.action</filename> for things that
6413 really shouldn't be filtered, like code on CVS->Web interfaces. Since
6414 <filename>user.action</filename> has the last word, these exceptions
6415 won't be valid for the <quote>fun</quote> filtering specified here.
6419 You might also worry about how your favourite free websites are
6420 funded, and find that they rely on displaying banner advertisements
6421 to survive. So you might want to specifically allow banners for those
6422 sites that you feel provide value to you:
6434 Note that <literal>allow-ads</literal> has been aliased to
6435 <literal>-<link linkend="block">block</link></literal>,
6436 <literal>-<link linkend="filter-banners-by-size">filter{banners-by-size}</link></literal>, and
6437 <literal>-<link linkend="filter-banners-by-link">filter{banners-by-link}</link></literal> above.
6441 Invoke another alias here to force an over-ride of the MIME type <literal>
6442 application/x-sh</literal> which typically would open a download type
6443 dialog. In my case, I want to look at the shell script, and then I can save
6444 it should I choose to.
6454 <filename>user.action</filename> is generally the best place to define
6455 exceptions and additions to the default policies of
6456 <filename>default.action</filename>. Some actions are safe to have their
6457 default policies set here though. So let's set a default policy to have a
6458 <quote>blank</quote> image as opposed to the checkerboard pattern for
6459 <emphasis>ALL</emphasis> sites. <quote>/</quote> of course matches all URL
6465 { +<link linkend="set-image-blocker">set-image-blocker{blank}</link> }
6466 / # ALL sites</screen>
6472 <!-- ~ End section ~ -->
6476 <!-- ~ End section ~ -->
6478 <!-- ~~~~~~~~ New section Header ~~~~~~~~~ -->
6480 <sect1 id="filter-file">
6481 <title>Filter Files</title>
6484 On-the-fly text substitutions need
6485 to be defined in a <quote>filter file</quote>. Once defined, they
6486 can then be invoked as an <quote>action</quote>.
6490 &my-app; supports three different filter actions:
6491 <literal><link linkend="filter">filter</link></literal> to
6492 rewrite the content that is send to the client,
6493 <literal><link linkend="client-header-filter">client-header-filter</link></literal>
6494 to rewrite headers that are send by the client, and
6495 <literal><link linkend="server-header-filter">server-header-filter</link></literal>
6496 to rewrite headers that are send by the server.
6500 &my-app; also supports two tagger actions:
6501 <literal><link linkend="client-header-tagger">client-header-tagger</link></literal>
6503 <literal><link linkend="server-header-tagger">server-header-tagger</link></literal>.
6504 Taggers and filters use the same syntax in the filter files, the difference
6505 is that taggers don't modify the text they are filtering, but use a rewritten
6506 version of the filtered text as tag. The tags can then be used to change the
6507 applying actions through sections with <link linkend="tag-pattern">tag-patterns</link>.
6512 Multiple filter files can be defined through the <literal> <link
6513 linkend="filterfile">filterfile</link></literal> config directive. The filters
6514 as supplied by the developers are located in
6515 <filename>default.filter</filename>. It is recommended that any locally
6516 defined or modified filters go in a separately defined file such as
6517 <filename>user.filter</filename>.
6521 Common tasks for content filters are to eliminate common annoyances in
6522 HTML and JavaScript, such as pop-up windows,
6523 exit consoles, crippled windows without navigation tools, the
6524 infamous <BLINK> tag etc, to suppress images with certain
6525 width and height attributes (standard banner sizes or web-bugs),
6526 or just to have fun.
6530 Enabled content filters are applied to any content whose
6531 <quote>Content Type</quote> header is recognised as a sign
6532 of text-based content, with the exception of <literal>text/plain</literal>.
6533 Use the <link linkend="FORCE-TEXT-MODE">force-text-mode</link> action
6534 to also filter other content.
6538 Substitutions are made at the source level, so if you want to <quote>roll
6539 your own</quote> filters, you should first be familiar with HTML syntax,
6540 and, of course, regular expressions.
6544 Just like the <link linkend="actions-file">actions files</link>, the
6545 filter file is organized in sections, which are called <emphasis>filters</emphasis>
6546 here. Each filter consists of a heading line, that starts with one of the
6547 <emphasis>keywords</emphasis> <literal>FILTER:</literal>,
6548 <literal>CLIENT-HEADER-FILTER:</literal> or <literal>SERVER-HEADER-FILTER:</literal>
6549 followed by the filter's <emphasis>name</emphasis>, and a short (one line)
6550 <emphasis>description</emphasis> of what it does. Below that line
6551 come the <emphasis>jobs</emphasis>, i.e. lines that define the actual
6552 text substitutions. By convention, the name of a filter
6553 should describe what the filter <emphasis>eliminates</emphasis>. The
6554 comment is used in the <ulink url="http://config.privoxy.org/">web-based
6555 user interface</ulink>.
6559 Once a filter called <replaceable>name</replaceable> has been defined
6560 in the filter file, it can be invoked by using an action of the form
6561 +<literal><link linkend="filter">filter</link>{<replaceable>name</replaceable>}</literal>
6562 in any <link linkend="actions-file">actions file</link>.
6566 Filter definitions start with a header line that contains the filter
6567 type, the filter name and the filter description.
6568 A content filter header line for a filter called <quote>foo</quote> could look
6573 <screen>FILTER: foo Replace all "foo" with "bar"</screen>
6577 Below that line, and up to the next header line, come the jobs that
6578 define what text replacements the filter executes. They are specified
6579 in a syntax that imitates <ulink url="http://www.perl.org/">Perl</ulink>'s
6580 <literal>s///</literal> operator. If you are familiar with Perl, you
6581 will find this to be quite intuitive, and may want to look at the
6582 PCRS documentation for the subtle differences to Perl behaviour. Most
6583 notably, the non-standard option letter <literal>U</literal> is supported,
6584 which turns the default to ungreedy matching.
6589 <ulink url="http://en.wikipedia.org/wiki/Regular_expressions"><quote>Regular
6590 Expressions</quote></ulink>, you might want to take a look at
6591 the <link linkend="regex">Appendix on regular expressions</link>, and
6592 see the <ulink url="http://perldoc.perl.org/perlre.html">Perl
6594 <ulink url="http://perldoc.perl.org/perlop.html">the
6595 <literal>s///</literal> operator's syntax</ulink> and <ulink
6596 url="http://perldoc.perl.org/perlre.html">Perl-style regular
6597 expressions</ulink> in general.
6598 The below examples might also help to get you started.
6602 <!-- ~~~~~~~~ New section Header ~~~~~~~~~ -->
6604 <sect2><title>Filter File Tutorial</title>
6606 Now, let's complete our <quote>foo</quote> content filter. We have already defined
6607 the heading, but the jobs are still missing. Since all it does is to replace
6608 <quote>foo</quote> with <quote>bar</quote>, there is only one (trivial) job
6613 <screen>s/foo/bar/</screen>
6617 But wait! Didn't the comment say that <emphasis>all</emphasis> occurrences
6618 of <quote>foo</quote> should be replaced? Our current job will only take
6619 care of the first <quote>foo</quote> on each page. For global substitution,
6620 we'll need to add the <literal>g</literal> option:
6624 <screen>s/foo/bar/g</screen>
6628 Our complete filter now looks like this:
6631 <screen>FILTER: foo Replace all "foo" with "bar"
6632 s/foo/bar/g</screen>
6636 Let's look at some real filters for more interesting examples. Here you see
6637 a filter that protects against some common annoyances that arise from JavaScript
6638 abuse. Let's look at its jobs one after the other:
6644 FILTER: js-annoyances Get rid of particularly annoying JavaScript abuse
6646 # Get rid of JavaScript referrer tracking. Test page: http://www.randomoddness.com/untitled.htm
6648 s|(<script.*)document\.referrer(.*</script>)|$1"Not Your Business!"$2|Usg</screen>
6652 Following the header line and a comment, you see the job. Note that it uses
6653 <literal>|</literal> as the delimiter instead of <literal>/</literal>, because
6654 the pattern contains a forward slash, which would otherwise have to be escaped
6655 by a backslash (<literal>\</literal>).
6659 Now, let's examine the pattern: it starts with the text <literal><script.*</literal>
6660 enclosed in parentheses. Since the dot matches any character, and <literal>*</literal>
6661 means: <quote>Match an arbitrary number of the element left of myself</quote>, this
6662 matches <quote><script</quote>, followed by <emphasis>any</emphasis> text, i.e.
6663 it matches the whole page, from the start of the first <script> tag.
6667 That's more than we want, but the pattern continues: <literal>document\.referrer</literal>
6668 matches only the exact string <quote>document.referrer</quote>. The dot needed to
6669 be <emphasis>escaped</emphasis>, i.e. preceded by a backslash, to take away its
6670 special meaning as a joker, and make it just a regular dot. So far, the meaning is:
6671 Match from the start of the first <script> tag in a the page, up to, and including,
6672 the text <quote>document.referrer</quote>, if <emphasis>both</emphasis> are present
6673 in the page (and appear in that order).
6677 But there's still more pattern to go. The next element, again enclosed in parentheses,
6678 is <literal>.*</script></literal>. You already know what <literal>.*</literal>
6679 means, so the whole pattern translates to: Match from the start of the first <script>
6680 tag in a page to the end of the last <script> tag, provided that the text
6681 <quote>document.referrer</quote> appears somewhere in between.
6685 This is still not the whole story, since we have ignored the options and the parentheses:
6686 The portions of the page matched by sub-patterns that are enclosed in parentheses, will be
6687 remembered and be available through the variables <literal>$1, $2, ...</literal> in
6688 the substitute. The <literal>U</literal> option switches to ungreedy matching, which means
6689 that the first <literal>.*</literal> in the pattern will only <quote>eat up</quote> all
6690 text in between <quote><script</quote> and the <emphasis>first</emphasis> occurrence
6691 of <quote>document.referrer</quote>, and that the second <literal>.*</literal> will
6692 only span the text up to the <emphasis>first</emphasis> <quote></script></quote>
6693 tag. Furthermore, the <literal>s</literal> option says that the match may span
6694 multiple lines in the page, and the <literal>g</literal> option again means that the
6695 substitution is global.
6699 So, to summarize, the pattern means: Match all scripts that contain the text
6700 <quote>document.referrer</quote>. Remember the parts of the script from
6701 (and including) the start tag up to (and excluding) the string
6702 <quote>document.referrer</quote> as <literal>$1</literal>, and the part following
6703 that string, up to and including the closing tag, as <literal>$2</literal>.
6707 Now the pattern is deciphered, but wasn't this about substituting things? So
6708 lets look at the substitute: <literal>$1"Not Your Business!"$2</literal> is
6709 easy to read: The text remembered as <literal>$1</literal>, followed by
6710 <literal>"Not Your Business!"</literal> (<emphasis>including</emphasis>
6711 the quotation marks!), followed by the text remembered as <literal>$2</literal>.
6712 This produces an exact copy of the original string, with the middle part
6713 (the <quote>document.referrer</quote>) replaced by <literal>"Not Your
6714 Business!"</literal>.
6718 The whole job now reads: Replace <quote>document.referrer</quote> by
6719 <literal>"Not Your Business!"</literal> wherever it appears inside a
6720 <script> tag. Note that this job won't break JavaScript syntax,
6721 since both the original and the replacement are syntactically valid
6722 string objects. The script just won't have access to the referrer
6723 information anymore.
6727 We'll show you two other jobs from the JavaScript taming department, but
6728 this time only point out the constructs of special interest:
6733 # The status bar is for displaying link targets, not pointless blahblah
6735 s/window\.status\s*=\s*(['"]).*?\1/dUmMy=1/ig</screen>
6739 <literal>\s</literal> stands for whitespace characters (space, tab, newline,
6740 carriage return, form feed), so that <literal>\s*</literal> means: <quote>zero
6741 or more whitespace</quote>. The <literal>?</literal> in <literal>.*?</literal>
6742 makes this matching of arbitrary text ungreedy. (Note that the <literal>U</literal>
6743 option is not set). The <literal>['"]</literal> construct means: <quote>a single
6744 <emphasis>or</emphasis> a double quote</quote>. Finally, <literal>\1</literal> is
6745 a back-reference to the first parenthesis just like <literal>$1</literal> above,
6746 with the difference that in the <emphasis>pattern</emphasis>, a backslash indicates
6747 a back-reference, whereas in the <emphasis>substitute</emphasis>, it's the dollar.
6751 So what does this job do? It replaces assignments of single- or double-quoted
6752 strings to the <quote>window.status</quote> object with a dummy assignment
6753 (using a variable name that is hopefully odd enough not to conflict with
6754 real variables in scripts). Thus, it catches many cases where e.g. pointless
6755 descriptions are displayed in the status bar instead of the link target when
6756 you move your mouse over links.
6761 # Kill OnUnload popups. Yummy. Test: http://www.zdnet.com/zdsubs/yahoo/tree/yfs.html
6763 s/(<body [^>]*)onunload(.*>)/$1never$2/iU</screen>
6768 <ulink url="http://www.w3.org/TR/2000/REC-DOM-Level-2-Events-20001113/events.html#Events-eventgroupings-htmlevents">OnUnload
6769 event binding</ulink> in the HTML DOM was a <emphasis>CRIME</emphasis>.
6770 When I close a browser window, I want it to close and die. Basta.
6771 This job replaces the <quote>onunload</quote> attribute in
6772 <quote><body></quote> tags with the dummy word <literal>never</literal>.
6773 Note that the <literal>i</literal> option makes the pattern matching
6774 case-insensitive. Also note that ungreedy matching alone doesn't always guarantee
6775 a minimal match: In the first parenthesis, we had to use <literal>[^>]*</literal>
6776 instead of <literal>.*</literal> to prevent the match from exceeding the
6777 <body> tag if it doesn't contain <quote>OnUnload</quote>, but the page's
6782 The last example is from the fun department:
6787 FILTER: fun Fun text replacements
6789 # Spice the daily news:
6791 s/microsoft(?!\.com)/MicroSuck/ig</screen>
6795 Note the <literal>(?!\.com)</literal> part (a so-called negative lookahead)
6796 in the job's pattern, which means: Don't match, if the string
6797 <quote>.com</quote> appears directly following <quote>microsoft</quote>
6798 in the page. This prevents links to microsoft.com from being trashed, while
6799 still replacing the word everywhere else.
6804 # Buzzword Bingo (example for extended regex syntax)
6806 s* industry[ -]leading \
6808 | customer[ -]focused \
6809 | market[ -]driven \
6810 | award[ -]winning # Comments are OK, too! \
6811 | high[ -]performance \
6812 | solutions[ -]based \
6816 *<font color="red"><b>BINGO!</b></font> \
6821 The <literal>x</literal> option in this job turns on extended syntax, and allows for
6822 e.g. the liberal use of (non-interpreted!) whitespace for nicer formatting.
6830 <!-- ~~~~~~~~ New section Header ~~~~~~~~~ -->
6832 <sect2 id="predefined-filters"><title>The Pre-defined Filters</title>
6836 Note each filter is also listed in the +filter action section above. Please
6837 keep these listings in sync.
6842 The distribution <filename>default.filter</filename> file contains a selection of
6843 pre-defined filters for your convenience:
6848 <term><emphasis>js-annoyances</emphasis></term>
6851 The purpose of this filter is to get rid of particularly annoying JavaScript abuse.
6856 replaces JavaScript references to the browser's referrer information
6857 with the string "Not Your Business!". This compliments the <literal><link
6858 linkend="hide-referrer">hide-referrer</link></literal> action on the content level.
6863 removes the bindings to the DOM's
6864 <ulink url="http://www.w3.org/TR/2000/REC-DOM-Level-2-Events-20001113/events.html#Events-eventgroupings-htmlevents">unload
6865 event</ulink> which we feel has no right to exist and is responsible for most <quote>exit consoles</quote>, i.e.
6866 nasty windows that pop up when you close another one.
6871 removes code that causes new windows to be opened with undesired properties, such as being
6872 full-screen, non-resizeable, without location, status or menu bar etc.
6878 Use with caution. This is an aggressive filter, and can break sites that
6879 rely heavily on JavaScript.
6885 <term><emphasis>js-events</emphasis></term>
6888 This is a very radical measure. It removes virtually all JavaScript event bindings, which
6889 means that scripts can not react to user actions such as mouse movements or clicks, window
6890 resizing etc, anymore. Use with caution!
6893 We <emphasis>strongly discourage</emphasis> using this filter as a default since it breaks
6894 many legitimate scripts. It is meant for use only on extra-nasty sites (should you really
6901 <term><emphasis>html-annoyances</emphasis></term>
6904 This filter will undo many common instances of HTML based abuse.
6907 The <literal>BLINK</literal> and <literal>MARQUEE</literal> tags
6908 are neutralized (yeah baby!), and browser windows will be created as
6909 resizeable (as of course they should be!), and will have location,
6910 scroll and menu bars -- even if specified otherwise.
6916 <term><emphasis>content-cookies</emphasis></term>
6919 Most cookies are set in the HTTP dialog, where they can be intercepted
6921 <literal><link linkend="crunch-incoming-cookies">crunch-incoming-cookies</link></literal>
6922 and <literal><link linkend="crunch-outgoing-cookies">crunch-outgoing-cookies</link></literal>
6923 actions. But web sites increasingly make use of HTML meta tags and JavaScript
6924 to sneak cookies to the browser on the content level.
6927 This filter disables most HTML and JavaScript code that reads or sets
6928 cookies. It cannot detect all clever uses of these types of code, so it
6929 should not be relied on as an absolute fix. Use it wherever you would also
6930 use the cookie crunch actions.
6936 <term><emphasis>refresh-tags</emphasis></term>
6939 Disable any refresh tags if the interval is greater than nine seconds (so
6940 that redirections done via refresh tags are not destroyed). This is useful
6941 for dial-on-demand setups, or for those who find this HTML feature
6948 <term><emphasis>unsolicited-popups</emphasis></term>
6951 This filter attempts to prevent only <quote>unsolicited</quote> pop-up
6952 windows from opening, yet still allow pop-up windows that the user
6953 has explicitly chosen to open. It was added in version 3.0.1,
6954 as an improvement over earlier such filters.
6957 Technical note: The filter works by redefining the window.open JavaScript
6958 function to a dummy function, <literal>PrivoxyWindowOpen()</literal>,
6959 during the loading and rendering phase of each HTML page access, and
6960 restoring the function afterward.
6963 This is recommended only for browsers that cannot perform this function
6964 reliably themselves. And be aware that some sites require such windows
6965 in order to function normally. Use with caution.
6971 <term><emphasis>all-popups</emphasis></term>
6974 Attempt to prevent <emphasis>all</emphasis> pop-up windows from opening.
6975 Note this should be used with even more discretion than the above, since
6976 it is more likely to break some sites that require pop-ups for normal
6977 usage. Use with caution.
6983 <term><emphasis>img-reorder</emphasis></term>
6986 This is a helper filter that has no value if used alone. It makes the
6987 <literal>banners-by-size</literal> and <literal>banners-by-link</literal>
6988 (see below) filters more effective and should be enabled together with them.
6994 <term><emphasis>banners-by-size</emphasis></term>
6997 This filter removes image tags purely based on what size they are. Fortunately
6998 for us, many ads and banner images tend to conform to certain standardized
6999 sizes, which makes this filter quite effective for ad stripping purposes.
7002 Occasionally this filter will cause false positives on images that are not ads,
7003 but just happen to be of one of the standard banner sizes.
7006 Recommended only for those who require extreme ad blocking. The default
7007 block rules should catch 95+% of all ads <emphasis>without</emphasis> this filter enabled.
7013 <term><emphasis>banners-by-link</emphasis></term>
7016 This is an experimental filter that attempts to kill any banners if
7017 their URLs seem to point to known or suspected click trackers. It is currently
7018 not of much value and is not recommended for use by default.
7024 <term><emphasis>webbugs</emphasis></term>
7027 Webbugs are small, invisible images (technically 1X1 GIF images), that
7028 are used to track users across websites, and collect information on them.
7029 As an HTML page is loaded by the browser, an embedded image tag causes the
7030 browser to contact a third-party site, disclosing the tracking information
7031 through the requested URL and/or cookies for that third-party domain, without
7032 the user ever becoming aware of the interaction with the third-party site.
7033 HTML-ized spam also uses a similar technique to verify email addresses.
7036 This filter removes the HTML code that loads such <quote>webbugs</quote>.
7042 <term><emphasis>tiny-textforms</emphasis></term>
7045 A rather special-purpose filter that can be used to enlarge textareas (those
7046 multi-line text boxes in web forms) and turn off hard word wrap in them.
7047 It was written for the sourceforge.net tracker system where such boxes are
7048 a nuisance, but it can be handy on other sites, too.
7051 It is not recommended to use this filter as a default.
7057 <term><emphasis>jumping-windows</emphasis></term>
7060 Many consider windows that move, or resize themselves to be abusive. This filter
7061 neutralizes the related JavaScript code. Note that some sites might not display
7062 or behave as intended when using this filter. Use with caution.
7068 <term><emphasis>frameset-borders</emphasis></term>
7071 Some web designers seem to assume that everyone in the world will view their
7072 web sites using the same browser brand and version, screen resolution etc,
7073 because only that assumption could explain why they'd use static frame sizes,
7074 yet prevent their frames from being resized by the user, should they be too
7075 small to show their whole content.
7078 This filter removes the related HTML code. It should only be applied to sites
7085 <term><emphasis>demoronizer</emphasis></term>
7088 Many Microsoft products that generate HTML use non-standard extensions (read:
7089 violations) of the ISO 8859-1 aka Latin-1 character set. This can cause those
7090 HTML documents to display with errors on standard-compliant platforms.
7093 This filter translates the MS-only characters into Latin-1 equivalents.
7094 It is not necessary when using MS products, and will cause corruption of
7095 all documents that use 8-bit character sets other than Latin-1. It's mostly
7096 worthwhile for Europeans on non-MS platforms, if weird garbage characters
7097 sometimes appear on some pages, or user agents that don't correct for this on
7100 My version of Mozilla (ancient) shows litte square boxes for quote
7101 characters, and apostrophes on moronized pages. So many pages have this, I
7102 can read them fine now. HB 08/27/06
7109 <term><emphasis>shockwave-flash</emphasis></term>
7112 A filter for shockwave haters. As the name suggests, this filter strips code
7113 out of web pages that is used to embed shockwave flash objects.
7121 <term><emphasis>quicktime-kioskmode</emphasis></term>
7124 Change HTML code that embeds Quicktime objects so that kioskmode, which
7125 prevents saving, is disabled.
7131 <term><emphasis>fun</emphasis></term>
7134 Text replacements for subversive browsing fun. Make fun of your favorite
7135 Monopolist or play buzzword bingo.
7141 <term><emphasis>crude-parental</emphasis></term>
7144 A demonstration-only filter that shows how <application>Privoxy</application>
7145 can be used to delete web content on a keyword basis.
7151 <term><emphasis>ie-exploits</emphasis></term>
7154 An experimental collection of text replacements to disable malicious HTML and JavaScript
7155 code that exploits known security holes in Internet Explorer.
7158 Presently, it only protects against Nimda and a cross-site scripting bug, and
7159 would need active maintenance to provide more substantial protection.
7165 <term><emphasis>site-specifics</emphasis></term>
7168 Some web sites have very specific problems, the cure for which doesn't apply
7169 anywhere else, or could even cause damage on other sites.
7172 This is a collection of such site-specific cures which should only be applied
7173 to the sites they were intended for, which is what the supplied
7174 <filename>default.action</filename> file does. Users shouldn't need to change
7175 anything regarding this filter.
7181 <term><emphasis>google</emphasis></term>
7184 A CSS based block for Google text ads. Also removes a width limitation
7185 and the toolbar advertisement.
7191 <term><emphasis>yahoo</emphasis></term>
7194 Another CSS based block, this time for Yahoo text ads. And removes
7195 a width limitation as well.
7201 <term><emphasis>msn</emphasis></term>
7204 Another CSS based block, this time for MSN text ads. And removes
7205 tracking URLs, as well as a width limitation.
7211 <term><emphasis>blogspot</emphasis></term>
7214 Cleans up some Blogspot blogs. Read the fine print before using this one!
7217 This filter also intentionally removes some navigation stuff and sets the
7218 page width to 100%. As a result, some rounded <quote>corners</quote> would
7219 appear to early or not at all and as fixing this would require a browser
7220 that understands background-size (CSS3), they are removed instead.
7226 <term><emphasis>xml-to-html</emphasis></term>
7229 Server-header filter to change the Content-Type from xml to html.
7235 <term><emphasis>html-to-xml</emphasis></term>
7238 Server-header filter to change the Content-Type from html to xml.
7244 <term><emphasis>no-ping</emphasis></term>
7247 Removes the non-standard <literal>ping</literal> attribute from
7248 anchor and area HTML tags.
7254 <term><emphasis>hide-tor-exit-notation</emphasis></term>
7257 Client-header filter to remove the <command>Tor</command> exit node notation
7258 found in Host and Referer headers.
7261 If &my-app; and <command>Tor</command> are chained and &my-app;
7262 is configured to use socks4a, one can use <quote>http://www.example.org.foobar.exit/</quote>
7263 to access the host <quote>www.example.org</quote> through the
7264 <command>Tor</command> exit node <quote>foobar</quote>.
7267 As the HTTP client isn't aware of this notation, it treats the
7268 whole string <quote>www.example.org.foobar.exit</quote> as host and uses it
7269 for the <quote>Host</quote> and <quote>Referer</quote> headers. From the
7270 server's point of view the resulting headers are invalid and can cause problems.
7273 An invalid <quote>Referer</quote> header can trigger <quote>hot-linking</quote>
7274 protections, an invalid <quote>Host</quote> header will make it impossible for
7275 the server to find the right vhost (several domains hosted on the same IP address).
7278 This client-header filter removes the <quote>foo.exit</quote> part in those headers
7279 to prevent the mentioned problems. Note that it only modifies
7280 the HTTP headers, it doesn't make it impossible for the server
7281 to detect your <command>Tor</command> exit node based on the IP address
7282 the request is coming from.
7289 <term><emphasis> </emphasis></term>
7303 <!-- ~ End section ~ -->
7307 <!-- ~~~~~ New section ~~~~~ -->
7309 <sect1 id="templates">
7310 <title>Privoxy's Template Files</title>
7312 All <application>Privoxy</application> built-in pages, i.e. error pages such as the
7313 <ulink url="http://show-the-404-error.page"><quote>404 - No Such Domain</quote>
7314 error page</ulink>, the <ulink
7315 url="http://ads.bannerserver.example.com/nasty-ads/sponsor.html"><quote>BLOCKED</quote>
7317 and all pages of its <ulink url="http://config.privoxy.org/">web-based
7318 user interface</ulink>, are generated from <emphasis>templates</emphasis>.
7319 (<application>Privoxy</application> must be running for the above links to work as
7324 These templates are stored in a subdirectory of the <link linkend="confdir">configuration
7325 directory</link> called <filename>templates</filename>. On Unixish platforms,
7327 <ulink url="file:///etc/privoxy/templates/"><filename>/etc/privoxy/templates/</filename></ulink>.
7331 The templates are basically normal HTML files, but with place-holders (called symbols
7332 or exports), which <application>Privoxy</application> fills at run time. It
7333 is possible to edit the templates with a normal text editor, should you want
7334 to customize them. (<emphasis>Not recommended for the casual
7335 user</emphasis>). Should you create your own custom templates, you should use
7336 the <filename>config</filename> setting <link linkend="templdir">templdir</link>
7337 to specify an alternate location, so your templates do not get overwritten
7341 Note that just like in configuration files, lines starting
7342 with <literal>#</literal> are ignored when the templates are filled in.
7346 The place-holders are of the form <literal>@name@</literal>, and you will
7347 find a list of available symbols, which vary from template to template,
7348 in the comments at the start of each file. Note that these comments are not
7349 always accurate, and that it's probably best to look at the existing HTML
7350 code to find out which symbols are supported and what they are filled in with.
7354 A special application of this substitution mechanism is to make whole
7355 blocks of HTML code disappear when a specific symbol is set. We use this
7356 for many purposes, one of them being to include the beta warning in all
7357 our user interface (CGI) pages when <application>Privoxy</application>
7358 is in an alpha or beta development stage:
7363 <!-- @if-unstable-start -->
7365 ... beta warning HTML code goes here ...
7367 <!-- if-unstable-end@ --></screen>
7371 If the "unstable" symbol is set, everything in between and including
7372 <literal>@if-unstable-start</literal> and <literal>if-unstable-end@</literal>
7373 will disappear, leaving nothing but an empty comment:
7377 <screen><!-- --></screen>
7381 There's also an if-then-else construct and an <literal>#include</literal>
7382 mechanism, but you'll sure find out if you are inclined to edit the
7387 All templates refer to a style located at
7388 <ulink url="http://config.privoxy.org/send-stylesheet"><literal>http://config.privoxy.org/send-stylesheet</literal></ulink>.
7389 This is, of course, locally served by <application>Privoxy</application>
7390 and the source for it can be found and edited in the
7391 <filename>cgi-style.css</filename> template.
7396 <!-- ~ End section ~ -->
7400 <!-- ~~~~~ New section ~~~~~ -->
7402 <sect1 id="contact"><title>Contacting the Developers, Bug Reporting and Feature
7405 <!-- Include contacting.sgml boilerplate: -->
7407 <!-- end boilerplate -->
7411 <!-- ~ End section ~ -->
7414 <!-- ~~~~~ New section ~~~~~ -->
7415 <sect1 id="copyright"><title>Privoxy Copyright, License and History</title>
7417 <!-- Include copyright.sgml: -->
7419 <!-- end copyright -->
7421 <!-- ~~~~~ New section ~~~~~ -->
7422 <sect2><title>License</title>
7423 <!-- Include copyright.sgml: -->
7425 <!-- end copyright -->
7427 <!-- ~ End section ~ -->
7430 <!-- ~~~~~ New section ~~~~~ -->
7432 <sect2 id="history"><title>History</title>
7433 <!-- Include history.sgml: -->
7435 <!-- end history -->
7438 <sect2 id="authors"><title>Authors</title>
7439 <!-- Include p-authors.sgml: -->
7441 <!-- end authors -->
7446 <!-- ~ End section ~ -->
7449 <!-- ~~~~~ New section ~~~~~ -->
7450 <sect1 id="seealso"><title>See Also</title>
7451 <!-- Include seealso.sgml: -->
7453 <!-- end seealso -->
7458 <!-- ~~~~~ New section ~~~~~ -->
7459 <sect1 id="appendix"><title>Appendix</title>
7462 <!-- ~~~~~ New section ~~~~~ -->
7464 <title>Regular Expressions</title>
7466 <application>Privoxy</application> uses Perl-style <quote>regular
7467 expressions</quote> in its <link linkend="actions-file">actions
7468 files</link> and <link linkend="filter-file">filter file</link>,
7469 through the <ulink url="http://www.pcre.org/">PCRE</ulink> and
7472 <ulink url="http://www.oesterhelt.org/pcrs/">PCRS</ulink> libraries.
7474 <application>PCRS</application> libraries.
7478 If you are reading this, you probably don't understand what <quote>regular
7479 expressions</quote> are, or what they can do. So this will be a very brief
7480 introduction only. A full explanation would require a <ulink
7481 url="http://www.oreilly.com/catalog/regex/">book</ulink> ;-)
7485 Regular expressions provide a language to describe patterns that can be
7486 run against strings of characters (letter, numbers, etc), to see if they
7487 match the string or not. The patterns are themselves (sometimes complex)
7488 strings of literal characters, combined with wild-cards, and other special
7489 characters, called meta-characters. The <quote>meta-characters</quote> have
7490 special meanings and are used to build complex patterns to be matched against.
7491 Perl Compatible Regular Expressions are an especially convenient
7492 <quote>dialect</quote> of the regular expression language.
7496 To make a simple analogy, we do something similar when we use wild-card
7497 characters when listing files with the <command>dir</command> command in DOS.
7498 <literal>*.*</literal> matches all filenames. The <quote>special</quote>
7499 character here is the asterisk which matches any and all characters. We can be
7500 more specific and use <literal>?</literal> to match just individual
7501 characters. So <quote>dir file?.text</quote> would match
7502 <quote>file1.txt</quote>, <quote>file2.txt</quote>, etc. We are pattern
7503 matching, using a similar technique to <quote>regular expressions</quote>!
7507 Regular expressions do essentially the same thing, but are much, much more
7508 powerful. There are many more <quote>special characters</quote> and ways of
7509 building complex patterns however. Let's look at a few of the common ones,
7510 and then some examples:
7515 <emphasis>.</emphasis> - Matches any single character, e.g. <quote>a</quote>,
7516 <quote>A</quote>, <quote>4</quote>, <quote>:</quote>, or <quote>@</quote>.
7518 </simplelist></para>
7522 <emphasis>?</emphasis> - The preceding character or expression is matched ZERO or ONE
7525 </simplelist></para>
7529 <emphasis>+</emphasis> - The preceding character or expression is matched ONE or MORE
7532 </simplelist></para>
7536 <emphasis>*</emphasis> - The preceding character or expression is matched ZERO or MORE
7539 </simplelist></para>
7543 <emphasis>\</emphasis> - The <quote>escape</quote> character denotes that
7544 the following character should be taken literally. This is used where one of the
7545 special characters (e.g. <quote>.</quote>) needs to be taken literally and
7546 not as a special meta-character. Example: <quote>example\.com</quote>, makes
7547 sure the period is recognized only as a period (and not expanded to its
7548 meta-character meaning of any single character).
7550 </simplelist></para>
7554 <emphasis>[ ]</emphasis> - Characters enclosed in brackets will be matched if
7555 any of the enclosed characters are encountered. For instance, <quote>[0-9]</quote>
7556 matches any numeric digit (zero through nine). As an example, we can combine
7557 this with <quote>+</quote> to match any digit one of more times: <quote>[0-9]+</quote>.
7559 </simplelist></para>
7563 <emphasis>( )</emphasis> - parentheses are used to group a sub-expression,
7564 or multiple sub-expressions.
7566 </simplelist></para>
7570 <emphasis>|</emphasis> - The <quote>bar</quote> character works like an
7571 <quote>or</quote> conditional statement. A match is successful if the
7572 sub-expression on either side of <quote>|</quote> matches. As an example:
7573 <quote>/(this|that) example/</quote> uses grouping and the bar character
7574 and would match either <quote>this example</quote> or <quote>that
7575 example</quote>, and nothing else.
7577 </simplelist></para>
7580 These are just some of the ones you are likely to use when matching URLs with
7581 <application>Privoxy</application>, and is a long way from a definitive
7582 list. This is enough to get us started with a few simple examples which may
7583 be more illuminating:
7587 <emphasis><literal>/.*/banners/.*</literal></emphasis> - A simple example
7588 that uses the common combination of <quote>.</quote> and <quote>*</quote> to
7589 denote any character, zero or more times. In other words, any string at all.
7590 So we start with a literal forward slash, then our regular expression pattern
7591 (<quote>.*</quote>) another literal forward slash, the string
7592 <quote>banners</quote>, another forward slash, and lastly another
7593 <quote>.*</quote>. We are building
7594 a directory path here. This will match any file with the path that has a
7595 directory named <quote>banners</quote> in it. The <quote>.*</quote> matches
7596 any characters, and this could conceivably be more forward slashes, so it
7597 might expand into a much longer looking path. For example, this could match:
7598 <quote>/eye/hate/spammers/banners/annoy_me_please.gif</quote>, or just
7599 <quote>/banners/annoying.html</quote>, or almost an infinite number of other
7600 possible combinations, just so it has <quote>banners</quote> in the path
7605 And now something a little more complex:
7609 <emphasis><literal>/.*/adv((er)?ts?|ertis(ing|ements?))?/</literal></emphasis> -
7610 We have several literal forward slashes again (<quote>/</quote>), so we are
7611 building another expression that is a file path statement. We have another
7612 <quote>.*</quote>, so we are matching against any conceivable sub-path, just so
7613 it matches our expression. The only true literal that <emphasis>must
7614 match</emphasis> our pattern is <application>adv</application>, together with
7615 the forward slashes. What comes after the <quote>adv</quote> string is the
7620 Remember the <quote>?</quote> means the preceding expression (either a
7621 literal character or anything grouped with <quote>(...)</quote> in this case)
7622 can exist or not, since this means either zero or one match. So
7623 <quote>((er)?ts?|ertis(ing|ements?))</quote> is optional, as are the
7624 individual sub-expressions: <quote>(er)</quote>,
7625 <quote>(ing|ements?)</quote>, and the <quote>s</quote>. The <quote>|</quote>
7626 means <quote>or</quote>. We have two of those. For instance,
7627 <quote>(ing|ements?)</quote>, can expand to match either <quote>ing</quote>
7628 <emphasis>OR</emphasis> <quote>ements?</quote>. What is being done here, is an
7629 attempt at matching as many variations of <quote>advertisement</quote>, and
7630 similar, as possible. So this would expand to match just <quote>adv</quote>,
7631 or <quote>advert</quote>, or <quote>adverts</quote>, or
7632 <quote>advertising</quote>, or <quote>advertisement</quote>, or
7633 <quote>advertisements</quote>. You get the idea. But it would not match
7634 <quote>advertizements</quote> (with a <quote>z</quote>). We could fix that by
7635 changing our regular expression to:
7636 <quote>/.*/adv((er)?ts?|erti(s|z)(ing|ements?))?/</quote>, which would then match
7641 <emphasis><literal>/.*/advert[0-9]+\.(gif|jpe?g)</literal></emphasis> - Again
7642 another path statement with forward slashes. Anything in the square brackets
7643 <quote>[ ]</quote> can be matched. This is using <quote>0-9</quote> as a
7644 shorthand expression to mean any digit one through nine. It is the same as
7645 saying <quote>0123456789</quote>. So any digit matches. The <quote>+</quote>
7646 means one or more of the preceding expression must be included. The preceding
7647 expression here is what is in the square brackets -- in this case, any digit
7648 one through nine. Then, at the end, we have a grouping: <quote>(gif|jpe?g)</quote>.
7649 This includes a <quote>|</quote>, so this needs to match the expression on
7650 either side of that bar character also. A simple <quote>gif</quote> on one side, and the other
7651 side will in turn match either <quote>jpeg</quote> or <quote>jpg</quote>,
7652 since the <quote>?</quote> means the letter <quote>e</quote> is optional and
7653 can be matched once or not at all. So we are building an expression here to
7654 match image GIF or JPEG type image file. It must include the literal
7655 string <quote>advert</quote>, then one or more digits, and a <quote>.</quote>
7656 (which is now a literal, and not a special character, since it is escaped
7657 with <quote>\</quote>), and lastly either <quote>gif</quote>, or
7658 <quote>jpeg</quote>, or <quote>jpg</quote>. Some possible matches would
7659 include: <quote>//advert1.jpg</quote>,
7660 <quote>/nasty/ads/advert1234.gif</quote>,
7661 <quote>/banners/from/hell/advert99.jpg</quote>. It would not match
7662 <quote>advert1.gif</quote> (no leading slash), or
7663 <quote>/adverts232.jpg</quote> (the expression does not include an
7664 <quote>s</quote>), or <quote>/advert1.jsp</quote> (<quote>jsp</quote> is not
7665 in the expression anywhere).
7669 We are barely scratching the surface of regular expressions here so that you
7670 can understand the default <application>Privoxy</application>
7671 configuration files, and maybe use this knowledge to customize your own
7672 installation. There is much, much more that can be done with regular
7673 expressions. Now that you know enough to get started, you can learn more on
7678 More reading on Perl Compatible Regular expressions:
7679 <ulink url="http://perldoc.perl.org/perlre.html">http://perldoc.perl.org/perlre.html</ulink>
7683 For information on regular expression based substitutions and their applications
7684 in filters, please see the <link linkend="filter-file">filter file tutorial</link>
7689 <!-- ~ End section ~ -->
7692 <!-- ~~~~~ New section ~~~~~ -->
7694 <title>Privoxy's Internal Pages</title>
7697 Since <application>Privoxy</application> proxies each requested
7698 web page, it is easy for <application>Privoxy</application> to
7699 trap certain special URLs. In this way, we can talk directly to
7700 <application>Privoxy</application>, and see how it is
7701 configured, see how our rules are being applied, change these
7702 rules and other configuration options, and even turn
7703 <application>Privoxy's</application> filtering off, all with
7709 The URLs listed below are the special ones that allow direct access
7710 to <application>Privoxy</application>. Of course,
7711 <application>Privoxy</application> must be running to access these. If
7712 not, you will get a friendly error message. Internet access is not
7725 <ulink url="http://config.privoxy.org/">http://config.privoxy.org/</ulink>
7729 There is a shortcut: <ulink url="http://p.p/">http://p.p/</ulink> (But it
7730 doesn't provide a fall-back to a real page, in case the request is not
7731 sent through <application>Privoxy</application>)
7737 Show information about the current configuration, including viewing and
7738 editing of actions files:
7742 <ulink url="http://config.privoxy.org/show-status">http://config.privoxy.org/show-status</ulink>
7749 Show the source code version numbers:
7753 <ulink url="http://config.privoxy.org/show-version">http://config.privoxy.org/show-version</ulink>
7760 Show the browser's request headers:
7764 <ulink url="http://config.privoxy.org/show-request">http://config.privoxy.org/show-request</ulink>
7771 Show which actions apply to a URL and why:
7775 <ulink url="http://config.privoxy.org/show-url-info">http://config.privoxy.org/show-url-info</ulink>
7782 Toggle Privoxy on or off. This feature can be turned off/on in the main
7783 <filename>config</filename> file. When toggled <quote>off</quote>, <quote>Privoxy</quote>
7784 continues to run, but only as a pass-through proxy, with no actions taking
7789 <ulink url="http://config.privoxy.org/toggle">http://config.privoxy.org/toggle</ulink>
7793 Short cuts. Turn off, then on:
7797 <ulink url="http://config.privoxy.org/toggle?set=disable">http://config.privoxy.org/toggle?set=disable</ulink>
7802 <ulink url="http://config.privoxy.org/toggle?set=enable">http://config.privoxy.org/toggle?set=enable</ulink>
7811 These may be bookmarked for quick reference. See next.
7815 <sect3 id="bookmarklets">
7816 <title>Bookmarklets</title>
7818 Below are some <quote>bookmarklets</quote> to allow you to easily access a
7819 <quote>mini</quote> version of some of <application>Privoxy's</application>
7820 special pages. They are designed for MS Internet Explorer, but should work
7821 equally well in Netscape, Mozilla, and other browsers which support
7822 JavaScript. They are designed to run directly from your bookmarks - not by
7823 clicking the links below (although that should work for testing).
7826 To save them, right-click the link and choose <quote>Add to Favorites</quote>
7827 (IE) or <quote>Add Bookmark</quote> (Netscape). You will get a warning that
7828 the bookmark <quote>may not be safe</quote> - just click OK. Then you can run the
7829 Bookmarklet directly from your favorites/bookmarks. For even faster access,
7830 you can put them on the <quote>Links</quote> bar (IE) or the <quote>Personal
7831 Toolbar</quote> (Netscape), and run them with a single click.
7840 url="javascript:void(window.open('http://config.privoxy.org/toggle?mini=y&set=enabled','ijbstatus','width=250,height=100,resizable=yes,scrollbars=no,toolbar=no,location=no,directories=no,status=no,menubar=no,copyhistory=no').focus());">Privoxy - Enable</ulink>
7847 url="javascript:void(window.open('http://config.privoxy.org/toggle?mini=y&set=disabled','ijbstatus','width=250,height=100,resizable=yes,scrollbars=no,toolbar=no,location=no,directories=no,status=no,menubar=no,copyhistory=no').focus());">Privoxy - Disable</ulink>
7854 url="javascript:void(window.open('http://config.privoxy.org/toggle?mini=y&set=toggle','ijbstatus','width=250,height=100,resizable=yes,scrollbars=no,toolbar=no,location=no,directories=no,status=no,menubar=no,copyhistory=no').focus());">Privoxy - Toggle Privoxy</ulink> (Toggles between enabled and disabled)
7861 url="javascript:void(window.open('http://config.privoxy.org/toggle?mini=y','ijbstatus','width=250,height=2,resizable=yes,scrollbars=no,toolbar=no,location=no,directories=no,status=no,menubar=no,copyhistory=no').focus());">Privoxy- View Status</ulink>
7867 <ulink url="javascript:w=Math.floor(screen.width/2);h=Math.floor(screen.height*0.9);void(window.open('http://www.privoxy.org/actions/index.php?url='+escape(location.href),'Feedback','screenx='+w+',width='+w+',height='+h+',scrollbars=yes,toolbar=no,location=no,directories=no,status=no,menubar=no,copyhistory=no').focus());">Privoxy - Submit Actions File Feedback</ulink>
7873 <ulink url="javascript:void(window.open('http://config.privoxy.org/show-url-info?url='+escape(location.href),'Why').focus());">Privoxy - Why?</ulink>
7880 Credit: The site which gave us the general idea for these bookmarklets is
7881 <ulink url="http://www.bookmarklets.com/">www.bookmarklets.com</ulink>. They
7882 have more information about bookmarklets.
7891 <!-- ~~~~~ New section ~~~~~ -->
7893 <title>Chain of Events</title>
7895 Let's take a quick look at how some of <application>Privoxy's</application>
7896 core features are triggered, and the ensuing sequence of events when a web
7897 page is requested by your browser:
7904 First, your web browser requests a web page. The browser knows to send
7905 the request to <application>Privoxy</application>, which will in turn,
7906 relay the request to the remote web server after passing the following
7912 <application>Privoxy</application> traps any request for its own internal CGI
7913 pages (e.g <ulink url="http://p.p/">http://p.p/</ulink>) and sends the CGI page back to the browser.
7918 Next, <application>Privoxy</application> checks to see if the URL
7920 linkend="BLOCK"><quote>+block</quote></link> patterns. If
7921 so, the URL is then blocked, and the remote web server will not be contacted.
7922 <link linkend="HANDLE-AS-IMAGE"><quote>+handle-as-image</quote></link>
7924 <link linkend="HANDLE-AS-EMPTY-DOCUMENT"><quote>+handle-as-empty-document</quote></link>
7925 are then checked, and if there is no match, an
7926 HTML <quote>BLOCKED</quote> page is sent back to the browser. Otherwise, if
7927 it does match, an image is returned for the former, and an empty text
7928 document for the latter. The type of image would depend on the setting of
7929 <link linkend="SET-IMAGE-BLOCKER"><quote>+set-image-blocker</quote></link>
7930 (blank, checkerboard pattern, or an HTTP redirect to an image elsewhere).
7935 Untrusted URLs are blocked. If URLs are being added to the
7936 <filename>trust</filename> file, then that is done.
7941 If the URL pattern matches the <link
7942 linkend="FAST-REDIRECTS"><quote>+fast-redirects</quote></link> action,
7943 it is then processed. Unwanted parts of the requested URL are stripped.
7948 Now the rest of the client browser's request headers are processed. If any
7949 of these match any of the relevant actions (e.g. <link
7950 linkend="HIDE-USER-AGENT"><quote>+hide-user-agent</quote></link>,
7951 etc.), headers are suppressed or forged as determined by these actions and
7957 Now the web server starts sending its response back (i.e. typically a web
7963 First, the server headers are read and processed to determine, among other
7964 things, the MIME type (document type) and encoding. The headers are then
7965 filtered as determined by the
7966 <link linkend="CRUNCH-INCOMING-COOKIES"><quote>+crunch-incoming-cookies</quote></link>,
7967 <link linkend="SESSION-COOKIES-ONLY"><quote>+session-cookies-only</quote></link>,
7968 and <link linkend="DOWNGRADE-HTTP-VERSION"><quote>+downgrade-http-version</quote></link>
7974 If any <link linkend="FILTER"><quote>+filter</quote></link> action
7976 linkend="DEANIMATE-GIFS"><quote>+deanimate-gifs</quote></link>
7977 action applies (and the document type fits the action), the rest of the page is
7978 read into memory (up to a configurable limit). Then the filter rules (from
7979 <filename>default.filter</filename> and any other filter files) are
7980 processed against the buffered content. Filters are applied in the order
7981 they are specified in one of the filter files. Animated GIFs, if present,
7982 are reduced to either the first or last frame, depending on the action
7983 setting.The entire page, which is now filtered, is then sent by
7984 <application>Privoxy</application> back to your browser.
7987 If neither a <link linkend="FILTER"><quote>+filter</quote></link> action
7989 linkend="DEANIMATE-GIFS"><quote>+deanimate-gifs</quote></link>
7990 matches, then <application>Privoxy</application> passes the raw data through
7991 to the client browser as it becomes available.
7996 As the browser receives the now (possibly filtered) page content, it
7997 reads and then requests any URLs that may be embedded within the page
7998 source, e.g. ad images, stylesheets, JavaScript, other HTML documents (e.g.
7999 frames), sounds, etc. For each of these objects, the browser issues a
8000 separate request (this is easily viewable in <application>Privoxy's</application>
8001 logs). And each such request is in turn processed just as above. Note that a
8002 complex web page will have many, many such embedded URLs. If these
8003 secondary requests are to a different server, then quite possibly a very
8004 differing set of actions is triggered.
8011 NOTE: This is somewhat of a simplistic overview of what happens with each URL
8012 request. For the sake of brevity and simplicity, we have focused on
8013 <application>Privoxy's</application> core features only.
8019 <!-- ~~~~~ New section ~~~~~ -->
8020 <sect2 id="actionsanat">
8021 <title>Troubleshooting: Anatomy of an Action</title>
8024 The way <application>Privoxy</application> applies
8025 <link linkend="ACTIONS">actions</link> and <link linkend="FILTER">filters</link>
8026 to any given URL can be complex, and not always so
8027 easy to understand what is happening. And sometimes we need to be able to
8028 <emphasis>see</emphasis> just what <application>Privoxy</application> is
8029 doing. Especially, if something <application>Privoxy</application> is doing
8030 is causing us a problem inadvertently. It can be a little daunting to look at
8031 the actions and filters files themselves, since they tend to be filled with
8032 <link linkend="regex">regular expressions</link> whose consequences are not
8037 One quick test to see if <application>Privoxy</application> is causing a problem
8038 or not, is to disable it temporarily. This should be the first troubleshooting
8039 step. See <link linkend="bookmarklets">the Bookmarklets</link> section on a quick
8040 and easy way to do this (be sure to flush caches afterward!). Looking at the
8041 logs is a good idea too. (Note that both the toggle feature and logging are
8042 enabled via <filename>config</filename> file settings, and may need to be
8043 turned <quote>on</quote>.)
8046 Another easy troubleshooting step to try is if you have done any
8047 customization of your installation, revert back to the installed
8048 defaults and see if that helps. There are times the developers get complaints
8049 about one thing or another, and the problem is more related to a customized
8050 configuration issue.
8054 <application>Privoxy</application> also provides the
8055 <ulink url="http://config.privoxy.org/show-url-info">http://config.privoxy.org/show-url-info</ulink>
8056 page that can show us very specifically how <application>actions</application>
8057 are being applied to any given URL. This is a big help for troubleshooting.
8061 First, enter one URL (or partial URL) at the prompt, and then
8062 <application>Privoxy</application> will tell us
8063 how the current configuration will handle it. This will not
8064 help with filtering effects (i.e. the <link
8065 linkend="FILTER"><quote>+filter</quote></link> action) from
8066 one of the filter files since this is handled very
8067 differently and not so easy to trap! It also will not tell you about any other
8068 URLs that may be embedded within the URL you are testing. For instance, images
8069 such as ads are expressed as URLs within the raw page source of HTML pages. So
8070 you will only get info for the actual URL that is pasted into the prompt area
8071 -- not any sub-URLs. If you want to know about embedded URLs like ads, you
8072 will have to dig those out of the HTML source. Use your browser's <quote>View
8073 Page Source</quote> option for this. Or right click on the ad, and grab the
8078 Let's try an example, <ulink url="http://google.com">google.com</ulink>,
8079 and look at it one section at a time in a sample configuration (your real
8080 configuration may vary):
8085 Matches for http://www.google.com:
8087 In file: default.action <guibutton>[ View ]</guibutton> <guibutton>[ Edit ]</guibutton>
8089 {+change-x-forwarded-for{block}
8090 +deanimate-gifs {last}
8091 +fast-redirects {check-decoded-url}
8092 +filter {refresh-tags}
8093 +filter {img-reorder}
8094 +filter {banners-by-size}
8096 +filter {jumping-windows}
8097 +filter {ie-exploits}
8098 +hide-from-header {block}
8099 +hide-referrer {forge}
8100 +session-cookies-only
8101 +set-image-blocker {pattern}
8104 { -session-cookies-only }
8110 In file: user.action <guibutton>[ View ]</guibutton> <guibutton>[ Edit ]</guibutton>
8111 (no matches in this file)
8116 This is telling us how we have defined our
8117 <link linkend="ACTIONS"><quote>actions</quote></link>, and
8118 which ones match for our test case, <quote>google.com</quote>.
8119 Displayed is all the actions that are available to us. Remember,
8120 the <literal>+</literal> sign denotes <quote>on</quote>. <literal>-</literal>
8121 denotes <quote>off</quote>. So some are <quote>on</quote> here, but many
8122 are <quote>off</quote>. Each example we try may provide a slightly different
8123 end result, depending on our configuration directives.
8127 is for our <filename>default.action</filename> file. The large, multi-line
8128 listing, is how the actions are set to match for all URLs, i.e. our default
8129 settings. If you look at your <quote>actions</quote> file, this would be the
8130 section just below the <quote>aliases</quote> section near the top. This
8131 will apply to all URLs as signified by the single forward slash at the end
8132 of the listing -- <quote> / </quote>.
8136 But we have defined additional actions that would be exceptions to these general
8137 rules, and then we list specific URLs (or patterns) that these exceptions
8138 would apply to. Last match wins. Just below this then are two explicit
8139 matches for <quote>.google.com</quote>. The first is negating our previous
8140 cookie setting, which was for <link
8141 linkend="SESSION-COOKIES-ONLY"><quote>+session-cookies-only</quote></link>
8142 (i.e. not persistent). So we will allow persistent cookies for google, at
8143 least that is how it is in this example. The second turns
8144 <emphasis>off</emphasis> any <link
8145 linkend="FAST-REDIRECTS"><quote>+fast-redirects</quote></link>
8146 action, allowing this to take place unmolested. Note that there is a leading
8147 dot here -- <quote>.google.com</quote>. This will match any hosts and
8148 sub-domains, in the google.com domain also, such as
8149 <quote>www.google.com</quote> or <quote>mail.google.com</quote>. But it would not
8150 match <quote>www.google.de</quote>! So, apparently, we have these two actions
8151 defined as exceptions to the general rules at the top somewhere in the lower
8152 part of our <filename>default.action</filename> file, and
8153 <quote>google.com</quote> is referenced somewhere in these latter sections.
8157 Then, for our <filename>user.action</filename> file, we again have no hits.
8158 So there is nothing google-specific that we might have added to our own, local
8159 configuration. If there was, those actions would over-rule any actions from
8160 previously processed files, such as <filename>default.action</filename>.
8161 <filename>user.action</filename> typically has the last word. This is the
8162 best place to put hard and fast exceptions,
8166 And finally we pull it all together in the bottom section and summarize how
8167 <application>Privoxy</application> is applying all its <quote>actions</quote>
8168 to <quote>google.com</quote>:
8179 +change-x-forwarded-for{block}
8180 -client-header-filter{hide-tor-exit-notation}
8181 -content-type-overwrite
8182 -crunch-client-header
8183 -crunch-if-none-match
8184 -crunch-incoming-cookies
8185 -crunch-outgoing-cookies
8186 -crunch-server-header
8187 +deanimate-gifs {last}
8188 -downgrade-http-version
8191 -filter {content-cookies}
8192 -filter {all-popups}
8193 -filter {banners-by-link}
8194 -filter {tiny-textforms}
8195 -filter {frameset-borders}
8196 -filter {demoronizer}
8197 -filter {shockwave-flash}
8198 -filter {quicktime-kioskmode}
8200 -filter {crude-parental}
8201 -filter {site-specifics}
8202 -filter {js-annoyances}
8203 -filter {html-annoyances}
8204 +filter {refresh-tags}
8205 -filter {unsolicited-popups}
8206 +filter {img-reorder}
8207 +filter {banners-by-size}
8209 +filter {jumping-windows}
8210 +filter {ie-exploits}
8217 -handle-as-empty-document
8219 -hide-accept-language
8220 -hide-content-disposition
8221 +hide-from-header {block}
8222 -hide-if-modified-since
8223 +hide-referrer {forge}
8226 -overwrite-last-modified
8227 -prevent-compression
8229 -server-header-filter{xml-to-html}
8230 -server-header-filter{html-to-xml}
8231 -session-cookies-only
8232 +set-image-blocker {pattern} </screen>
8236 Notice the only difference here to the previous listing, is to
8237 <quote>fast-redirects</quote> and <quote>session-cookies-only</quote>,
8238 which are activated specifically for this site in our configuration,
8239 and thus show in the <quote>Final Results</quote>.
8243 Now another example, <quote>ad.doubleclick.net</quote>:
8249 { +block{Domains starts with "ad"} }
8252 { +block{Domain contains "ad"} }
8255 { +block{Doubleclick banner server} +handle-as-image }
8256 .[a-vx-z]*.doubleclick.net
8261 We'll just show the interesting part here - the explicit matches. It is
8262 matched three different times. Two <quote>+block{}</quote> sections,
8263 and a <quote>+block{} +handle-as-image</quote>,
8264 which is the expanded form of one of our aliases that had been defined as:
8265 <quote>+block-as-image</quote>. (<link
8266 linkend="ALIASES"><quote>Aliases</quote></link> are defined in
8267 the first section of the actions file and typically used to combine more
8272 Any one of these would have done the trick and blocked this as an unwanted
8273 image. This is unnecessarily redundant since the last case effectively
8274 would also cover the first. No point in taking chances with these guys
8275 though ;-) Note that if you want an ad or obnoxious
8276 URL to be invisible, it should be defined as <quote>ad.doubleclick.net</quote>
8277 is done here -- as both a <link
8278 linkend="BLOCK"><quote>+block{}</quote></link>
8279 <emphasis>and</emphasis> an
8280 <link linkend="HANDLE-AS-IMAGE"><quote>+handle-as-image</quote></link>.
8281 The custom alias <quote><literal>+block-as-image</literal></quote> just
8282 simplifies the process and make it more readable.
8286 One last example. Let's try <quote>http://www.example.net/adsl/HOWTO/</quote>.
8287 This one is giving us problems. We are getting a blank page. Hmmm ...
8293 Matches for http://www.example.net/adsl/HOWTO/:
8295 In file: default.action <guibutton>[ View ]</guibutton> <guibutton>[ Edit ]</guibutton>
8299 +change-x-forwarded-for{block}
8300 -client-header-filter{hide-tor-exit-notation}
8301 -content-type-overwrite
8302 -crunch-client-header
8303 -crunch-if-none-match
8304 -crunch-incoming-cookies
8305 -crunch-outgoing-cookies
8306 -crunch-server-header
8308 -downgrade-http-version
8309 +fast-redirects {check-decoded-url}
8311 -filter {content-cookies}
8312 -filter {all-popups}
8313 -filter {banners-by-link}
8314 -filter {tiny-textforms}
8315 -filter {frameset-borders}
8316 -filter {demoronizer}
8317 -filter {shockwave-flash}
8318 -filter {quicktime-kioskmode}
8320 -filter {crude-parental}
8321 -filter {site-specifics}
8322 -filter {js-annoyances}
8323 -filter {html-annoyances}
8324 +filter {refresh-tags}
8325 -filter {unsolicited-popups}
8326 +filter {img-reorder}
8327 +filter {banners-by-size}
8329 +filter {jumping-windows}
8330 +filter {ie-exploits}
8337 -handle-as-empty-document
8339 -hide-accept-language
8340 -hide-content-disposition
8341 +hide-from-header{block}
8342 +hide-referer{forge}
8344 -overwrite-last-modified
8345 +prevent-compression
8347 -server-header-filter{xml-to-html}
8348 -server-header-filter{html-to-xml}
8349 +session-cookies-only
8350 +set-image-blocker{blank} }
8353 { +block{Path contains "ads".} +handle-as-image }
8359 Ooops, the <quote>/adsl/</quote> is matching <quote>/ads</quote> in our
8360 configuration! But we did not want this at all! Now we see why we get the
8361 blank page. It is actually triggering two different actions here, and
8362 the effects are aggregated so that the URL is blocked, and &my-app; is told
8363 to treat the block as if it were an image. But this is, of course, all wrong.
8364 We could now add a new action below this (or better in our own
8365 <filename>user.action</filename> file) that explicitly
8366 <emphasis>un</emphasis> blocks (
8367 <link linkend="BLOCK"><quote>{-block}</quote></link>) paths with
8368 <quote>adsl</quote> in them (remember, last match in the configuration
8369 wins). There are various ways to handle such exceptions. Example:
8381 Now the page displays ;-)
8382 Remember to flush your browser's caches when making these kinds of changes to
8383 your configuration to insure that you get a freshly delivered page! Or, try
8384 using <literal>Shift+Reload</literal>.
8388 But now what about a situation where we get no explicit matches like
8395 { +block{Path starts with "ads".} +handle-as-image }
8401 That actually was very helpful and pointed us quickly to where the problem
8402 was. If you don't get this kind of match, then it means one of the default
8403 rules in the first section of <filename>default.action</filename> is causing
8404 the problem. This would require some guesswork, and maybe a little trial and
8405 error to isolate the offending rule. One likely cause would be one of the
8406 <link linkend="FILTER"><quote>+filter</quote></link> actions.
8407 These tend to be harder to troubleshoot.
8408 Try adding the URL for the site to one of aliases that turn off
8409 <link linkend="FILTER"><quote>+filter</quote></link>:
8417 .worldpay.com # for quietpc.com
8425 <quote><literal>{ shop }</literal></quote> is an <quote>alias</quote> that expands to
8426 <quote><literal>{ -filter -session-cookies-only }</literal></quote>.
8427 Or you could do your own exception to negate filtering:
8435 # Disable ALL filter actions for sites in this section
8443 This would turn off all filtering for these sites. This is best
8444 put in <filename>user.action</filename>, for local site
8445 exceptions. Note that when a simple domain pattern is used by itself (without
8446 the subsequent path portion), all sub-pages within that domain are included
8447 automatically in the scope of the action.
8451 Images that are inexplicably being blocked, may well be hitting the
8452 <link linkend="FILTER-BANNERS-BY-SIZE"><quote>+filter{banners-by-size}</quote></link>
8454 that images of certain sizes are ad banners (works well
8455 <emphasis>most of the time</emphasis> since these tend to be standardized).
8459 <quote><literal>{ fragile }</literal></quote> is an alias that disables most
8460 actions that are the most likely to cause trouble. This can be used as a
8461 last resort for problem sites.
8467 # Handle with care: easy to break
8469 mybank.example.com</screen>
8474 <emphasis>Remember to flush caches!</emphasis> Note that the
8475 <literal>mail.google</literal> reference lacks the TLD portion (e.g.
8476 <quote>.com</quote>). This will effectively match any TLD with
8477 <literal>google</literal> in it, such as <literal>mail.google.de.</literal>,
8481 If this still does not work, you will have to go through the remaining
8482 actions one by one to find which one(s) is causing the problem.
8491 This program is free software; you can redistribute it
8492 and/or modify it under the terms of the GNU General
8493 Public License as published by the Free Software
8494 Foundation; either version 2 of the License, or (at
8495 your option) any later version.
8497 This program is distributed in the hope that it will
8498 be useful, but WITHOUT ANY WARRANTY; without even the
8499 implied warranty of MERCHANTABILITY or FITNESS FOR A
8500 PARTICULAR PURPOSE. See the GNU General Public
8501 License for more details.
8503 The GNU General Public License should be included with
8504 this file. If not, you can view it at
8505 http://www.gnu.org/copyleft/gpl.html
8506 or write to the Free Software Foundation, Inc.,
8507 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301,