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 p-version "3.0.20">
15 <!entity p-status "beta">
16 <!entity % p-authors-formal "INCLUDE"> <!-- include additional text, etc -->
17 <!entity % p-not-stable "INCLUDE">
18 <!entity % p-stable "IGNORE">
19 <!entity % p-text "IGNORE"> <!-- define we are not a text only doc -->
20 <!entity % p-doc "INCLUDE"> <!-- and we are a formal doc -->
21 <!entity % p-readme "IGNORE">
22 <!entity % user-man "IGNORE">
23 <!entity % config-file "IGNORE">
24 <!entity % p-supp-userman "IGNORE"> <!-- Omit some from supported.sgml -->
25 <!entity my-copy "©"> <!-- kludge for docbook2man -->
26 <!entity % draft "IGNORE"> <!-- WIP stuff -->
27 <!entity % seealso-extra "INCLUDE"> <!-- extra stuff from seealso.sgml -->
28 <!entity my-app "<application>Privoxy</application>">
31 File : $Source: /cvsroot/ijbswa/current/doc/source/user-manual.sgml,v $
34 This file belongs into
35 ijbswa.sourceforge.net:/home/groups/i/ij/ijbswa/htdocs/
37 $Id: user-manual.sgml,v 2.163 2013/01/18 12:31:41 fabiankeil Exp $
39 Copyright (C) 2001-2013 Privoxy Developers http://www.privoxy.org/
42 ========================================================================
43 NOTE: Please read developer-manual/documentation.html before touching
44 anything in this, or other Privoxy documentation.
45 ========================================================================
52 <title>Privoxy &p-version; User Manual</title>
56 <!-- Completely the wrong markup, but very little is allowed -->
57 <!-- in this part of an article. FIXME -->
58 <link linkend="copyright">Copyright</link> &my-copy; 2001-2013 by
59 <ulink url="http://www.privoxy.org/">Privoxy Developers</ulink>
63 <pubdate>$Id: user-manual.sgml,v 2.163 2013/01/18 12:31:41 fabiankeil Exp $</pubdate>
67 Note: the following should generate a separate page, and a live link to it,
68 all nicely done. But it doesn't for some mysterious reason. Please leave
69 commented unless it can be fixed proper. For the time being, the
70 copyright/license declarations will be in their own sgml.
83 This is here to keep vim syntax file from breaking :/
84 If I knew enough to fix it, I would.
85 PLEASE DO NOT REMOVE! HB: hal@foobox.net
91 The <citetitle>Privoxy User Manual</citetitle> gives users information on how to
92 install, configure and use <ulink
93 url="http://www.privoxy.org/">Privoxy</ulink>.
96 <!-- Include privoxy.sgml boilerplate: -->
98 <!-- end privoxy.sgml -->
101 You can find the latest version of the <citetitle>Privoxy User Manual</citetitle> at <ulink
102 url="http://www.privoxy.org/user-manual/">http://www.privoxy.org/user-manual/</ulink>.
103 Please see the <link linkend="contact">Contact section</link> on how to
104 contact the developers.
108 <!-- Feel free to send a note to the developers at <email>ijbswa-developers@lists.sourceforge.net</email>. -->
114 <!-- ~~~~~ New section ~~~~~ -->
115 <sect1 label="1" id="introduction"><title>Introduction</title>
117 This documentation is included with the current &p-status; version of
118 <application>Privoxy</application>, v.&p-version;<![%p-not-stable;[,
119 and is mostly complete at this point. The most up to date reference for the
120 time being is still the comments in the source files and in the individual
121 configuration files. Development of a new version is currently nearing
122 completion, and includes significant changes and enhancements over
126 <!-- include only in non-stable versions -->
129 Since this is a &p-status; version, not all new features are well tested. This
130 documentation may be slightly out of sync as a result (especially with
131 CVS sources). And there <emphasis>may be</emphasis> bugs, though hopefully
136 <!-- ~~~~~ New section ~~~~~ -->
137 <sect2 id="features"><title>Features</title>
139 In addition to the core
140 features of ad blocking and
141 <ulink url="http://en.wikipedia.org/wiki/Browser_cookie">cookie</ulink> management,
142 <application>Privoxy</application> provides many supplemental
143 features<![%p-not-stable;[, some of them currently under development]]>,
144 that give the end-user more control, more privacy and more freedom:
146 <!-- Include newfeatures.sgml boilerplate here: -->
148 <!-- end boilerplate -->
153 <!-- ~ End section ~ -->
156 <!-- ~~~~~ New section ~~~~~ -->
157 <sect1 id="installation"><title>Installation</title>
160 <application>Privoxy</application> is available both in convenient pre-compiled
161 packages for a wide range of operating systems, and as raw source code.
162 For most users, we recommend using the packages, which can be downloaded from our
163 <ulink url="http://sourceforge.net/projects/ijbswa/">Privoxy Project
169 On some platforms, the installer may remove previously installed versions, if
170 found. (See below for your platform). In any case <emphasis>be sure to backup
171 your old configuration if it is valuable to you.</emphasis> See the <link
172 linkend="upgradersnote">note to upgraders</link> section below.
175 <!-- ~~~~~ New section ~~~~~ -->
176 <sect2 id="installation-packages"><title>Binary Packages</title>
178 How to install the binary packages depends on your operating system:
181 <!-- XXX: The installation sections should be sorted -->
183 <!-- ~~~~~ New section ~~~~~ -->
184 <sect3 id="installation-deb"><title>Debian and Ubuntu</title>
186 DEBs can be installed with <literal>apt-get install privoxy</literal>,
187 and will use <filename>/etc/privoxy</filename> for the location of
192 <!-- ~~~~~ New section ~~~~~ -->
193 <sect3 id="installation-pack-win"><title>Windows</title>
196 Just double-click the installer, which will guide you through
197 the installation process. You will find the configuration files
198 in the same directory as you installed <application>Privoxy</application> in.
201 Version 3.0.5 beta introduced full <application>Windows</application> service
202 functionality. On Windows only, the <application>Privoxy</application>
203 program has two new command line arguments to install and uninstall
204 <application>Privoxy</application> as a <emphasis>service</emphasis>.
208 <term>Arguments:</term>
211 <replaceable class="parameter">--install</replaceable>[:<replaceable class="parameter">service_name</replaceable>]
214 <replaceable class="parameter">--uninstall</replaceable>[:<replaceable class="parameter">service_name</replaceable>]
220 After invoking <application>Privoxy</application> with
221 <command>--install</command>, you will need to bring up the
222 <application>Windows</application> service console to assign the user you
223 want <application>Privoxy</application> to run under, and whether or not you
224 want it to run whenever the system starts. You can start the
225 <application>Windows</application> services console with the following
226 command: <command>services.msc</command>. If you do not take the manual step
227 of modifying <application>Privoxy's</application> service settings, it will
228 not start. Note too that you will need to give Privoxy a user account that
229 actually exists, or it will not be permitted to
230 write to its log and configuration files.
235 <!-- ~~~~~ New section ~~~~~ -->
236 <sect3 id="installation-os2"><title>OS/2</title>
239 First, make sure that no previous installations of
240 <application>Junkbuster</application> and / or
241 <application>Privoxy</application> are left on your
242 system. Check that no <application>Junkbuster</application>
243 or <application>Privoxy</application> objects are in
249 Then, just double-click the WarpIN self-installing archive, which will
250 guide you through the installation process. A shadow of the
251 <application>Privoxy</application> executable will be placed in your
252 startup folder so it will start automatically whenever OS/2 starts.
256 The directory you choose to install <application>Privoxy</application>
257 into will contain all of the configuration files.
261 <!-- ~~~~~ New section ~~~~~ -->
262 <sect3 id="installation-mac"><title>Mac OS X</title>
264 Installation instructions for the OS X platform depend upon whether
265 you downloaded a ready-built installation package (.pkg or .mpkg) or have
266 downloaded the source code.
269 <sect3 renderas="sect4" id="OS-X-install-from-package">
270 <title>Installation from ready-built package</title>
272 The downloaded file will either be a .pkg (for OS X 10.5 upwards) or a bzipped
273 .mpkg file (for OS X 10.4). The former can be double-clicked as is and the
274 installation will start; double-clicking the latter will unzip the .mpkg file
275 which can then be double-clicked to commence the installation.
278 The privoxy service will automatically start after a successful installation
279 (and thereafter every time your computer starts up) however you will need to
280 configure your web browser(s) to use it. To do so, configure them to use a
281 proxy for HTTP and HTTPS at the address 127.0.0.1:8118.
284 To prevent the privoxy service from automatically starting when your computer
285 starts up, remove or rename the file <literal>/Library/LaunchDaemons/org.ijbswa.privoxy.plist</literal>
286 (on OS X 10.5 and higher) or the folder named
287 <literal>/Library/StartupItems/Privoxy</literal> (on OS X 10.4 'Tiger').
290 To manually start or stop the privoxy service, use the scripts startPrivoxy.sh
291 and stopPrivoxy.sh supplied in /Applications/Privoxy. They must be run from an
292 administrator account, using sudo.
295 To uninstall, run /Applications/Privoxy/uninstall.command as sudo from an
296 administrator account.
299 <sect3 renderas="sect4" id="OS-X-install-from-source">
300 <title>Installation from source</title>
302 To build and install the Privoxy source code on OS X you will need to obtain
303 the macsetup module from the Privoxy Sourceforge CVS repository (refer to
304 Sourceforge help for details of how to set up a CVS client to have read-only
305 access to the repository). This module contains scripts that leverage the usual
306 open-source tools (available as part of Apple's free of charge Xcode
307 distribution or via the usual open-source software package managers for OS X
308 (MacPorts, Homebrew, Fink etc.) to build and then install the privoxy binary
309 and associated files. The macsetup module's README file contains complete
310 instructions for its use.
313 The privoxy service will automatically start after a successful installation
314 (and thereafter every time your computer starts up) however you will need to
315 configure your web browser(s) to use it. To do so, configure them to use a
316 proxy for HTTP and HTTPS at the address 127.0.0.1:8118.
319 To prevent the privoxy service from automatically starting when your computer
320 starts up, remove or rename the file <literal>/Library/LaunchDaemons/org.ijbswa.privoxy.plist</literal>
321 (on OS X 10.5 and higher) or the folder named
322 <literal>/Library/StartupItems/Privoxy</literal> (on OS X 10.4 'Tiger').
325 To manually start or stop the privoxy service, use the Privoxy Utility
326 for Mac OS X (also part of the macsetup module). This application can start
327 and stop the privoxy service and display its log and configuration files.
330 To uninstall, run the macsetup module's uninstall.sh as sudo from an
331 administrator account.
335 <!-- ~~~~~ New section ~~~~~ -->
336 <sect3 id="installation-tbz"><title>FreeBSD</title>
339 Privoxy is part of FreeBSD's Ports Collection, you can build and install
340 it with <literal>cd /usr/ports/www/privoxy; make install clean</literal>.
343 If you don't use the ports, you can fetch and install
344 the package with <literal>pkg_add -r privoxy</literal>.
347 The port skeleton and the package can also be downloaded from the
348 <ulink url="https://sourceforge.net/project/showfiles.php?group_id=11118">File Release
349 Page</ulink>, but there's no reason to use them unless you're interested in the
350 beta releases which are only available there.
356 <!-- ~~~~~ New section ~~~~~ -->
357 <sect2 id="installation-source"><title>Building from Source</title>
360 The most convenient way to obtain the <application>Privoxy</application> sources
361 is to download the source tarball from our
362 <ulink url="http://sourceforge.net/project/showfiles.php?group_id=11118&package_id=10571">project download
367 If you like to live on the bleeding edge and are not afraid of using
368 possibly unstable development versions, you can check out the up-to-the-minute
369 version directly from <ulink url="http://sourceforge.net/cvs/?group_id=11118">the
370 CVS repository</ulink>.
372 deprecated...out of business.
373 or simply download <ulink
374 url="http://cvs.sourceforge.net/cvstarballs/ijbswa-cvsroot.tar.bz2">the nightly CVS
379 <!-- include buildsource.sgml boilerplate: -->
381 <!-- end boilerplate -->
384 <!-- ~~~~~ New section ~~~~~ -->
385 <sect2 id="installation-keepupdated"><title>Keeping your Installation Up-to-Date</title>
388 If you wish to receive an email notification whenever we release updates of
389 <application>Privoxy</application> or the actions file, <ulink
390 url="http://lists.sourceforge.net/lists/listinfo/ijbswa-announce/">subscribe
391 to our announce mailing list</ulink>, ijbswa-announce@lists.sourceforge.net.
395 In order not to lose your personal changes and adjustments when updating
396 to the latest <literal>default.action</literal> file we <emphasis>strongly
397 recommend</emphasis> that you use <literal>user.action</literal> and
398 <literal>user.filter</literal> for your local
399 customizations of <application>Privoxy</application>. See the <link
400 linkend="actions-file">Chapter on actions files</link> for details.
408 <!-- ~ End section ~ -->
410 <!-- ~~~~~ New section ~~~~~ -->
411 <sect1 id="whatsnew">
412 <title>What's New in this Release</title>
414 <application>Privoxy 3.0.20</application> is a beta release.
415 The changes since 3.0.19 stable are:
426 Client sockets are now properly shutdown and drained before being
427 closed. This fixes page truncation issues with clients that aggressively
428 pipeline data on platforms that otherwise discard already written data.
429 The issue mainly affected Opera users and was initially reported
430 by Kevin in #3464439, szotsaki provided additional information to track
436 Fix latency calculation for shared connections (disabled by default).
437 It was broken since their introduction in 2009. The calculated latency
438 for most connections would be 0 in which case the timeout detection
439 failed to account for the real latency.
444 Reject URLs with invalid port. Previously they were parsed incorrectly and
445 characters between the port number and the first slash were silently
446 dropped as shown by curl test 187.
451 The default-server-timeout and socket-timeout directives accept 0 as
457 Fix a race condition on Windows that could cause Privoxy to become
458 unresponsive after toggling it on or off through the taskbar icon.
459 Reported by Tim H. in #3525694.
464 Fix the compilation on Windows when configured without IPv6 support.
469 Fix an assertion that could cause debug builds to abort() in case of
470 socks5 connection failures with "debug 2" enabled.
475 Fix an assertion that could cause debug builds to abort() if a filter
476 contained nul bytes in the replacement text.
484 General improvements:
488 Significantly improved keep-alive support for both client and server
494 New debug log level 65536 which logs all actions that were applied to
500 New directive client-header-order to forward client headers in a
501 different order than the one in which they arrived.
506 New directive tolerate-pipelining to allow client-side pipelining.
507 If enabled (3.0.20 beta enables it by default), Privoxy will keep
508 pipelined client requests around to deal with them once the current
509 request has been served.
514 New --config-test option to let Privoxy exit after checking whether or not
515 the configuration seems valid. The limitations noted in TODO #22 and #23
516 still apply. Based on a patch by Ramkumar Chinchani.
521 New limit-cookie-lifetime{} action to let cookies expire before the end
522 of the session. Suggested by Rick Sykes in #1049575.
527 Increase the hard-coded maximum number of actions and filter files from
528 10 to 30 (each). It doesn't significantly affect Privoxy's memory usage
529 and recompiling wasn't an option for all Privoxy users that reached the
535 Add support for chunk-encoded client request bodies. Previously
536 chunk-encoded request bodies weren't guaranteed to be forwarded correctly,
537 so this can also be considered a bug fix although chunk-encoded request
538 bodies aren't commonly used in the real world.
543 Add support for Tor's optimistic-data SOCKS extension, which can reduce the
544 latency for requests on newly created connections. Currently only the
545 headers are sent optimistically and only if the client request has already
546 been read completely which rules out requests with large bodies.
551 After preventing the client from pipelining, don't signal keep-alive
552 intentions. When looking at the response headers alone, it previously
553 wasn't obvious from the client's perspective that no additional responses
559 Stop considering client sockets tainted after receiving a request with body.
560 It hasn't been necessary for a while now and unnecessarily causes test
561 failures when using curl's test suite.
566 Allow HTTP/1.0 clients to signal interest in keep-alive through the
567 Proxy-Connection header. While such client are rare in the real world, it
568 doesn't hurt and couple of curl tests rely on it.
573 Only remove duplicated Content-Type headers when filters are enabled.
574 If they are not it doesn't cause ill effects and the user might not want it.
575 Downgrade the removal message to LOG_LEVEL_HEADER to clarify that it's not
576 an error in Privoxy and is unlikely to cause any problems in general.
577 Anonymously reported in #3599335.
582 Set the socket option SO_LINGER for the client socket.
587 Move several variable declarations to the beginning of their code block.
588 It's required when compiling with gcc 2.95 which is still used on some
589 platforms. Initial patch submitted by Simon South in #3564815.
594 Optionally try to sanity-check strptime() results before trusting them.
595 Broken strptime() implementations have caused problems in the past and
596 the most recent offender seems to be FreeBSD's libc (standards/173421).
601 When filtering is enabled, let Range headers pass if the range starts at
602 the beginning. This should work around (or at least reduce) the video
603 playback issues with various Apple clients as reported by Duc in #3426305.
608 Do not confuse a client hanging up with a connection time out. If a client
609 closes its side of the connection without sending a request line, do not
610 send the CLIENT_CONNECTION_TIMEOUT_RESPONSE, but report the condition
616 Allow closing curly braces as part of action values as long as they are
622 On Windows, the logfile is now written before showing the GUI error
623 message which blocks until the user acknowledges it.
624 Reported by Adriaan in #3593603.
629 Remove an unreasonable parameter limit in the CGI interface. The new
630 parameter limit depends on the memory available and is currently unlikely
631 to be reachable, due to other limits in both Privoxy and common clients.
632 Reported by Andrew on ijbswa-users@.
637 Decrease the chances of parse failures after requests with unsupported
638 methods were sent to the CGI interface.
646 Action file improvements:
650 Remove the comment that indicated that updated default.action versions
651 are released on their own.
656 Block 'optimize.indieclick.com/' and 'optimized-by.rubiconproject.com/'
661 Unblock 'adjamblog.wordpress.com/' and 'adjamblog.files.wordpress.com/'.
662 Reported by Ryan Farmer in #3496116.
667 Unblock '/.*Bugtracker'. Reported by pwhk in #3522341.
672 Add test URLs for '.freebsd.org' and '.watson.org'.
677 Unblock '.urbandictionary.com/popular'.
687 Block 'farm.plista.com/widgetdata.php'.
692 Block 'rotation.linuxnewmedia.com/'.
697 Block 'reklamy.sfd.pl/'. Reported by kacperdominik in #3399948.
702 Block 'g.adspeed.net/'.
707 Unblock 'websupport.wdc.com/'. Reported by Adam Piggot in #3577851.
712 Block '/openx/www/delivery/'.
717 Disable fast-redirects for '.googleapis.com/'.
722 Block 'imp.double.net/'. Reported by David Bo in #3070411.
727 Block 'gm-link.com/' which is used for email tracking.
728 Reported by David Bo in #1812733.
733 Verify that requests to "bwp." are blocked. URL taken from #1736879
734 submitted by Francois Marier.
739 Block '/.*bannerid='. Reported by Adam Piggott in #2975779.
744 Block 'cltomedia.info/delivery/' and '.adexprt.com/'.
745 Anonymously reported in #2965254.
750 Block 'de17a.com/'. Reported by David Bo in #3061472.
755 Block 'oskar.tradera.com/'. Reported by David Bo in #3060596.
760 Block '/scripts/webtrends\.js'. Reported by johnd16 in #3002729.
765 Block requests for 'pool.*.adhese.com/'. Reported by johnd16 in #3002716.
770 Update path pattern for Coremetrics and add tests.
771 Pattern and URLs submitted by Adam Piggott #3168443.
776 Enable +fast-redirects{check-decoded-url} for 'tr.anp.se/'.
777 Reported by David Bo in #3268832.
782 Unblock '.conrad.se/newsletter/banners/'. Reported by David Bo in #3413824.
787 Block '.tynt.com/'. Reported by Dan Stahlke in #3421767.
792 Unblock '.bbci.co.uk/radio/'. Reported by Adam Piggott in #3569603.
797 Block requests to 'service.maxymiser.net/'.
798 Reported by johnd16 in #3118401 (with a previous URL).
803 Disable fast-redirects for Google's "let's pretend your computer is
809 Unblock '/.*download' to resolve actionsfile feedback #3498129.
810 Submitted by Steven Kolins (soundcloud.com not working).
815 Unblock '.wlxrs.com/' which is required by hotmail.com.
816 Fixes #3413827 submitted by David Bo.
821 Add two unblock patterns for popup radio and TV players.
822 Submitted by Adam Piggott in #3596089.
830 Filter file improvements & bug fixes:
834 Add a referer tagger.
839 Reduce the likelihood that the google filter messes up HTML-generating
840 JavaScript. Reported by Zeno Kugy in #3520260.
848 Documentation improvements:
852 Revised all OS X sections due to new packaging module (OSXPackageBuilder).
857 Update the list of supported operating systems to clarify that all Windows
858 versions after 95 are expected to work and note that the platform-specific
859 code for AmigaOS and QNX currently isn't maintained.
864 Update 'Signals' section, the only explicitly handled signals are SIGINT,
870 Add Haiku to the list of operating systems on which Privoxy is known to
876 Add DragonFly to the list of BSDs on which Privoxy is known to run.
881 Removed references to redhat-specific documentation set since it no longer
887 Removed references to building PDFs since we no longer do so.
892 Multiple listen-address directives are supported since 3.0.18, correct the
893 documentation to say so.
898 Remove bogus section about long and short being preferable to int.
903 Corrected some Internet JunkBuster references to Privoxy.
908 Removed references to www.junkbusters.com since it is no longer
909 maintained. Reported by Angelina Matson.
914 Various grammar and spelling corrections
919 Add a client-header-tagger{} example for disabling filtering for range
925 Correct a URL in the "Privoxy with Tor" FAQ.
930 Spell 'refresh-tags' correctly. Reported by Don in #3571927.
935 Sort manpage options alphabetically.
940 Remove an incorrect sentence in the toggle section. The toggle state
941 doesn't affect whether or not the Windows version uses the tray icon.
942 Reported by Zeno Kugy in #3596395.
947 Add new contributors since 3.0.19.
955 Log message improvements:
959 When stopping to watch a client socket due to pipelining, additionally log
965 Log the client socket and its condition before closing it. This makes it
966 more obvious that the socket actually gets closed and should help when
967 diagnosing problems like #3464439.
972 In case of SOCKS5 failures, do not explicitly log the server's response.
973 It hasn't helped so far and the response can already be logged by enabling
974 "debug 32768" anyway. This reverts v1.81 and the follow-up bug fix v1.84.
979 Relocate the connection-accepted message from listen_loop() to serve().
980 This way it's printed by the thread that is actually serving the
981 connection which is nice when grepping for thread ids in log files.
993 Remove compatibility layer for versions prior to 3.0 since it has been
994 obsolete for more than 10 years now.
999 Remove the ijb_isupper() and ijb_tolower() macros from parsers.c since
1000 they aren't used in this file.
1005 Removed the 'Functions declared include:' comment sections since they tend
1006 to be incomplete, incorrect and out of date and the benefit seems
1012 Various comment grammar and comprehensibility improvements.
1017 Remove a pointless fflush() call in chat(). Flushing all streams pretty
1018 much all the time for no obvious reason is ridiculous.
1023 Relocate ijb_isupper()'s definition to project.h and get the ijb_tolower()
1024 definition from there, too.
1029 Relocate ijb_isdigit()'s definition to project.h.
1034 Rename ijb_foo macros to privoxy_foo.
1039 Add malloc_or_die() which will allow to simplify code paths where malloc()
1040 failures don't need to be handled gracefully.
1045 Add strdup_or_die() which will allow to simplify code paths where strdup()
1046 failures don't need to be handled gracefully.
1051 Replace strdup() calls with strdup_or_die() calls where it's safe and
1052 simplifies the code.
1057 Fix white-space around parentheses.
1062 Add missing white-space behind if's and the following parentheses.
1067 Unwrap a memcpy() call in resolve_hostname_to_ip().
1072 Declare pcrs_get_delimiter()'s delimiters[] static const.
1077 Various optimisations to remove dead code and merge inefficient code
1078 structures for improved clarity, performance or code compactness.
1083 Various data type corrections.
1088 Change visibility of several code segments when compiling without
1089 FEATURE_CONNECTION_KEEP_ALIVE enabled for clarity.
1094 In pcrs_get_delimiter(), do not use delimiters outside the ASCII range.
1095 Fixes a clang complaint.
1100 Fix an error message in get_last_url() nobody is supposed to see.
1101 Reported by Matthew Fischer in #3507301.
1106 Fix a typo in the no-zlib-support complaint. Patch submitted by Matthew
1107 Fischer in #3507304.
1112 Shorten ssplit()'s prototype by removing the last two arguments. We always
1113 want to skip empty fields and ignore leading delimiters, so having
1114 parameters for this only complicates the API.
1119 Use an enum for the type of the action value.
1124 Rename action_name's member takes_value to value_type as it isn't used as
1130 Turn family mismatches in match_sockaddr() into fatal errors.
1135 Let enlist_unique_header() verify that the caller didn't pass a header
1136 containing either \r or \n.
1141 Change the hashes used in load_config() to unsigned int. That's what
1142 hash_string() actually returns and using a potentially larger type
1148 Use privoxy_tolower() instead of vanilla tolower() with manual casting of
1154 Catch ssplit() failures in parse_cgi_parameters().
1162 Privoxy-Regression-Test:
1166 Add an 'Overwrite condition' directive to skip any matching tests before
1167 it. As it has a global scope, using it is more convenient than clowning
1168 around with the Ignore directive.
1173 Log to STDOUT instead of STDERR.
1178 Include the Privoxy version in the output.
1183 Various grammar and spelling corrections in documentation and code.
1188 Additional tests for range requests with filtering enabled.
1193 Tests with mostly invalid range request.
1198 Add a couple of hide-if-modified-since{} tests with different date formats.
1203 Cleaned up the format of the regression-tests.action file to match the
1204 format of default.action.
1209 Remove the "Copyright" line from print_version(). When using --help, every
1210 line of screen space matters and thus shouldn't be wasted on things the
1211 user doesn't care about.
1223 Improve the --statistics performance by skipping sanity checks for input
1224 that shouldn't affect the results anyway. Add a --strict-checks option
1225 that enables some of the checks again, just in case anybody cares.
1230 The distribution of client requests per connection is included in
1231 the --statistic output.
1236 The --accept-unknown-messages option has been removed and the behavior
1242 Accept and (mostly) highlight new log messages introduced with
1255 Bump generated Firefox version to 17.
1263 GNUmakefile improvements:
1267 The dok-tidy target no longer taints documents with a tidy-mark
1272 Change RA_MODE from 0664 to 0644. Suggested by Markus Dittrich in
1278 Remove tidy's clean flag as it changes the scope of attributes.
1279 Link-specific colors end up being applied to all text. Reported by Adam
1280 Piggott in #3569551.
1285 Leave it up to the user whether or not smart tags are inserted.
1290 Let w3m itself do the line wrapping for the config file. It works better
1291 than fmt as it can honour pre tags causing less unintentional line breaks.
1296 Ditch a pointless '-r' passed to rm to delete files.
1301 The config-file target now requires less manual intervention and updates
1302 the original config.
1307 Change WDUMP to generate ASCII. Add WDUMP_UTF8 to allow UTF-8 in the
1308 AUTHORS file so the names are right.
1313 Stop pretending that lynx and links are supported for the documentation.
1321 configure improvements:
1325 On Haiku, do not pass -lpthread to the compiler. Haiku's pthreads
1326 implementation is contained in its system library, libroot, so no
1327 additional library needs to be searched.
1328 Patch submitted by Simon South in #3564815.
1333 Additional Haiku-specific improvements. Disable checks intended for
1334 multi-user systems as Haiku is presently single-user. Group Haiku-specific
1335 settings in their own section, following the pattern for Solaris, OS/2 and
1336 AmigaOS. Add additional library-related settings to remove the need for
1337 providing configure with custom LDFLAGS.
1338 Submitted by Simon South in #3574538.
1348 <!-- ~~~~~ New section ~~~~~ -->
1350 <sect2 id="upgradersnote">
1351 <title>Note to Upgraders</title>
1354 A quick list of things to be aware of before upgrading from earlier
1355 versions of <application>Privoxy</application>:
1363 The recommended way to upgrade &my-app; is to backup your old
1364 configuration files, install the new ones, verify that &my-app;
1365 is working correctly and finally merge back your changes using
1366 <application>diff</application> and maybe <application>patch</application>.
1369 There are a number of new features in each &my-app; release and
1370 most of them have to be explicitly enabled in the configuration
1371 files. Old configuration files obviously don't do that and due
1372 to syntax changes using old configuration files with a new
1373 &my-app; isn't always possible anyway.
1378 Note that some installers remove earlier versions completely,
1379 including configuration files, therefore you should really save
1380 any important configuration files!
1385 On the other hand, other installers don't overwrite existing configuration
1386 files, thinking you will want to do that yourself.
1391 <filename>standard.action</filename> has been merged into
1392 the <filename>default.action</filename> file.
1397 In the default configuration only fatal errors are logged now.
1398 You can change that in the <link linkend="DEBUG">debug section</link>
1399 of the configuration file. You may also want to enable more verbose
1400 logging until you verified that the new &my-app; version is working
1407 Three other config file settings are now off by default:
1408 <link linkend="enable-remote-toggle">enable-remote-toggle</link>,
1409 <link linkend="enable-remote-http-toggle">enable-remote-http-toggle</link>,
1410 and <link linkend="enable-edit-actions">enable-edit-actions</link>.
1411 If you use or want these, you will need to explicitly enable them, and
1412 be aware of the security issues involved.
1419 What constitutes a <quote>default</quote> configuration has changed,
1420 and you may want to review which actions are <quote>on</quote> by
1421 default. This is primarily a matter of emphasis, but some features
1422 you may have been used to, may now be <quote>off</quote> by default.
1423 There are also a number of new actions and filters you may want to
1424 consider, most of which are not fully incorporated into the default
1425 settings as yet (see above).
1432 The default actions setting is now <literal>Cautious</literal>. Previous
1433 releases had a default setting of <literal>Medium</literal>. Experienced
1434 users may want to adjust this, as it is fairly conservative by &my-app;
1435 standards and past practices. See <ulink
1436 url="http://config.privoxy.org/edit-actions-list?f=default">
1437 http://config.privoxy.org/edit-actions-list?f=default</ulink>. New users
1438 should try the default settings for a while before turning up the volume.
1444 The default setting has filtering turned <emphasis>off</emphasis>, which
1445 subsequently means that compression is <emphasis>on</emphasis>. Remember
1446 that filtering does not work on compressed pages, so if you use, or want to
1447 use, filtering, you will need to force compression off. Example:
1451 { +<link linkend="filter">filter</link>{google} +<link linkend="prevent-compression">prevent-compression</link> }
1455 Or if you use a number of filters, or filter many sites, you may just want
1456 to turn off compression for all sites in
1457 <filename>default.action</filename> (or
1458 <filename>user.action</filename>).
1465 Also, <link linkend="SESSION-COOKIES-ONLY">session-cookies-only</link> is
1466 off by default now. If you've liked this feature in the past, you may want
1467 to turn it back on in <filename>user.action</filename> now.
1474 Some installers may not automatically start
1475 <application>Privoxy</application> after installation.
1486 <!-- ~~~~~ New section ~~~~~ -->
1487 <sect1 id="quickstart"><title>Quickstart to Using Privoxy</title>
1493 Install <application>Privoxy</application>. See the <link
1494 linkend="installation">Installation Section</link> below for platform specific
1501 Advanced users and those who want to offer <application>Privoxy</application>
1502 service to more than just their local machine should check the <link
1503 linkend="config">main config file</link>, especially the <link
1504 linkend="access-control">security-relevant</link> options. These are
1511 Start <application>Privoxy</application>, if the installation program has
1512 not done this already (may vary according to platform). See the section
1513 <link linkend="startup">Starting <application>Privoxy</application></link>.
1519 Set your browser to use <application>Privoxy</application> as HTTP and
1520 HTTPS (SSL) <ulink url="http://en.wikipedia.org/wiki/Proxy_server">proxy</ulink>
1521 by setting the proxy configuration for address of
1522 <literal>127.0.0.1</literal> and port <literal>8118</literal>.
1523 <emphasis>DO NOT</emphasis> activate proxying for <literal>FTP</literal> or
1524 any protocols besides HTTP and HTTPS (SSL) unless you intend to prevent your
1525 browser from using these protocols.
1531 Flush your browser's disk and memory caches, to remove any cached ad images.
1532 If using <application>Privoxy</application> to manage
1533 <ulink url="http://en.wikipedia.org/wiki/Browser_cookie">cookies</ulink>,
1534 you should remove any currently stored cookies too.
1540 A default installation should provide a reasonable starting point for
1541 most. There will undoubtedly be occasions where you will want to adjust the
1542 configuration, but that can be dealt with as the need arises. Little
1543 to no initial configuration is required in most cases, you may want
1545 <ulink url="config.html#ENABLE-EDIT-ACTIONS">web-based action editor</ulink> though.
1546 Be sure to read the warnings first.
1549 See the <link linkend="configuration">Configuration section</link> for more
1550 configuration options, and how to customize your installation.
1551 You might also want to look at the <link
1552 linkend="quickstart-ad-blocking">next section</link> for a quick
1553 introduction to how <application>Privoxy</application> blocks ads and
1560 If you experience ads that slip through, innocent images that are
1561 blocked, or otherwise feel the need to fine-tune
1562 <application>Privoxy's</application> behavior, take a look at the <link
1563 linkend="actions-file">actions files</link>. As a quick start, you might
1564 find the <link linkend="act-examples">richly commented examples</link>
1565 helpful. You can also view and edit the actions files through the <ulink
1566 url="http://config.privoxy.org">web-based user interface</ulink>. The
1567 Appendix <quote><link linkend="actionsanat">Troubleshooting: Anatomy of an
1568 Action</link></quote> has hints on how to understand and debug actions that
1569 <quote>misbehave</quote>.
1574 Did anyone test these lately?
1578 For easy access to &my-app;'s most important controls, drag the provided
1579 <link linkend="bookmarklets">Bookmarklets</link> into your browser's
1587 Please see the section <link linkend="contact">Contacting the
1588 Developers</link> on how to report bugs, problems with websites or to get
1595 Now enjoy surfing with enhanced control, comfort and privacy!
1603 <!-- ~~~~~ New section ~~~~~ -->
1605 <sect2 id="quickstart-ad-blocking">
1606 <title>Quickstart to Ad Blocking</title>
1608 NOTE: This section is deliberately redundant for those that don't
1609 want to read the whole thing (which is getting lengthy).
1612 Ad blocking is but one of <application>Privoxy's</application>
1613 array of features. Many of these features are for the technically minded advanced
1614 user. But, ad and banner blocking is surely common ground for everybody.
1617 This section will provide a quick summary of ad blocking so
1618 you can get up to speed quickly without having to read the more extensive
1619 information provided below, though this is highly recommended.
1622 First a bit of a warning ... blocking ads is much like blocking SPAM: the
1623 more aggressive you are about it, the more likely you are to block
1624 things that were not intended. And the more likely that some things
1625 may not work as intended. So there is a trade off here. If you want
1626 extreme ad free browsing, be prepared to deal with more
1627 <quote>problem</quote> sites, and to spend more time adjusting the
1628 configuration to solve these unintended consequences. In short, there is
1629 not an easy way to eliminate <emphasis>all</emphasis> ads. Either take
1630 the easy way and settle for <emphasis>most</emphasis> ads blocked with the
1631 default configuration, or jump in and tweak it for your personal surfing
1632 habits and preferences.
1635 Secondly, a brief explanation of <application>Privoxy's </application>
1636 <quote>actions</quote>. <quote>Actions</quote> in this context, are
1637 the directives we use to tell <application>Privoxy</application> to perform
1638 some task relating to HTTP transactions (i.e. web browsing). We tell
1639 <application>Privoxy</application> to take some <quote>action</quote>. Each
1640 action has a unique name and function. While there are many potential
1641 <application>actions</application> in <application>Privoxy's</application>
1642 arsenal, only a few are used for ad blocking. <link
1643 linkend="actions">Actions</link>, and <link linkend="actions-file">action
1644 configuration files</link>, are explained in depth below.
1647 Actions are specified in <application>Privoxy's</application> configuration,
1648 followed by one or more URLs to which the action should apply. URLs
1649 can actually be URL type <link linkend="af-patterns">patterns</link> that use
1650 wildcards so they can apply potentially to a range of similar URLs. The
1651 actions, together with the URL patterns are called a section.
1654 When you connect to a website, the full URL will either match one or more
1655 of the sections as defined in <application>Privoxy's</application> configuration,
1656 or not. If so, then <application>Privoxy</application> will perform the
1657 respective actions. If not, then nothing special happens. Furthermore, web
1658 pages may contain embedded, secondary URLs that your web browser will
1659 use to load additional components of the page, as it parses the
1660 original page's HTML content. An ad image for instance, is just an URL
1661 embedded in the page somewhere. The image itself may be on the same server,
1662 or a server somewhere else on the Internet. Complex web pages will have many
1663 such embedded URLs. &my-app; can deal with each URL individually, so, for
1664 instance, the main page text is not touched, but images from such-and-such
1669 The most important actions for basic ad blocking are: <literal><link
1670 linkend="block">block</link></literal>, <literal><link
1671 linkend="handle-as-image">handle-as-image</link></literal>,
1673 linkend="handle-as-empty-document">handle-as-empty-document</link></literal>,and
1674 <literal><link linkend="set-image-blocker">set-image-blocker</link></literal>:
1682 <literal><link linkend="block">block</link></literal> - this is perhaps
1683 the single most used action, and is particularly important for ad blocking.
1684 This action stops any contact between your browser and any URL patterns
1685 that match this action's configuration. It can be used for blocking ads,
1686 but also anything that is determined to be unwanted. By itself, it simply
1687 stops any communication with the remote server and sends
1688 <application>Privoxy</application>'s own built-in BLOCKED page instead to
1689 let you now what has happened (with some exceptions, see below).
1695 <literal><link linkend="handle-as-image">handle-as-image</link></literal> -
1696 tells <application>Privoxy</application> to treat this URL as an image.
1697 <application>Privoxy</application>'s default configuration already does this
1698 for all common image types (e.g. GIF), but there are many situations where this
1699 is not so easy to determine. So we'll force it in these cases. This is particularly
1700 important for ad blocking, since only if we know that it's an image of
1701 some kind, can we replace it with an image of our choosing, instead of the
1702 <application>Privoxy</application> BLOCKED page (which would only result in
1703 a <quote>broken image</quote> icon). There are some limitations to this
1704 though. For instance, you can't just brute-force an image substitution for
1705 an entire HTML page in most situations.
1711 <literal><link linkend="handle-as-empty-document">handle-as-empty-document</link></literal> -
1712 sends an empty document instead of <application>Privoxy's</application>
1713 normal BLOCKED HTML page. This is useful for file types that are neither
1714 HTML nor images, such as blocking JavaScript files.
1721 linkend="set-image-blocker">set-image-blocker</link></literal> - tells
1722 <application>Privoxy</application> what to display in place of an ad image that
1723 has hit a block rule. For this to come into play, the URL must match a
1724 <literal><link linkend="block">block</link></literal> action somewhere in the
1725 configuration, <emphasis>and</emphasis>, it must also match an
1726 <literal><link linkend="handle-as-image">handle-as-image</link></literal> action.
1729 The configuration options on what to display instead of the ad are:
1733 <emphasis>pattern</emphasis> - a checkerboard pattern, so that an ad
1734 replacement is obvious. This is the default.
1739 <emphasis>blank</emphasis> - A very small empty GIF image is displayed.
1740 This is the so-called <quote>invisible</quote> configuration option.
1745 <emphasis>http://<URL></emphasis> - A redirect to any image anywhere
1746 of the user's choosing (advanced usage).
1755 Advanced users will eventually want to explore &my-app;
1756 <literal><link linkend="filter">filters</link></literal> as well. Filters
1757 are very different from <literal><link
1758 linkend="block">blocks</link></literal>.
1759 A <quote>block</quote> blocks a site, page, or unwanted contented. Filters
1760 are a way of filtering or modifying what is actually on the page. An example
1761 filter usage: a text replacement of <quote>no-no</quote> for
1762 <quote>nasty-word</quote>. That is a very simple example. This process can be
1763 used for ad blocking, but it is more in the realm of advanced usage and has
1764 some pitfalls to be wary off.
1768 The quickest way to adjust any of these settings is with your browser through
1769 the special <application>Privoxy</application> editor at <ulink
1770 url="http://config.privoxy.org/show-status">http://config.privoxy.org/show-status</ulink>
1771 (shortcut: <ulink url="http://p.p/">http://p.p/show-status</ulink>). This
1772 is an internal page, and does not require Internet access.
1776 Note that as of <application>Privoxy</application> 3.0.7 beta the
1777 action editor is disabled by default. Check the
1778 <ulink url="config.html#ENABLE-EDIT-ACTIONS">enable-edit-actions
1779 section in the configuration file</ulink> to learn why and in which
1780 cases it's safe to enable again.
1784 If you decided to enable the action editor, select the appropriate
1785 <quote>actions</quote> file, and click
1786 <quote><guibutton>Edit</guibutton></quote>. It is best to put personal or
1787 local preferences in <filename>user.action</filename> since this is not
1788 meant to be overwritten during upgrades, and will over-ride the settings in
1789 other files. Here you can insert new <quote>actions</quote>, and URLs for ad
1790 blocking or other purposes, and make other adjustments to the configuration.
1791 <application>Privoxy</application> will detect these changes automatically.
1795 A quick and simple step by step example:
1803 Right click on the ad image to be blocked, then select
1804 <quote><guimenuitem>Copy Link Location</guimenuitem></quote> from the
1812 url="http://config.privoxy.org/show-status">http://config.privoxy.org/show-status</ulink>
1817 Find <filename>user.action</filename> in the top section, and click
1818 on <quote><guibutton>Edit</guibutton></quote>:
1821 <!-- image of editor and actions files selections -->
1823 <figure pgwide="0" float="0"><title>Actions Files in Use</title>
1826 <imagedata fileref="files-in-use.jpg" format="jpg">
1829 <phrase>[ Screenshot of Actions Files in Use ]</phrase>
1838 You should have a section with only
1839 <literal><link linkend="block">block</link></literal> listed under
1840 <quote>Actions:</quote>.
1841 If not, click a <quote><guibutton>Insert new section below</guibutton></quote>
1842 button, and in the new section that just appeared, click the
1843 <guibutton>Edit</guibutton> button right under the word <quote>Actions:</quote>.
1844 This will bring up a list of all actions. Find
1845 <literal><link linkend="block">block</link></literal> near the top, and click
1846 in the <quote>Enabled</quote> column, then <quote><guibutton>Submit</guibutton></quote>
1847 just below the list.
1852 Now, in the <literal><link linkend="block">block</link></literal> actions section,
1853 click the <quote><guibutton>Add</guibutton></quote> button, and paste the URL the
1854 browser got from <quote><guimenuitem>Copy Link Location</guimenuitem></quote>.
1855 Remove the <literal>http://</literal> at the beginning of the URL. Then, click
1856 <quote><guibutton>Submit</guibutton></quote> (or
1857 <quote><guibutton>OK</guibutton></quote> if in a pop-up window).
1862 Now go back to the original page, and press <keycap>SHIFT-Reload</keycap>
1863 (or flush all browser caches). The image should be gone now.
1871 This is a very crude and simple example. There might be good reasons to use a
1872 wildcard pattern match to include potentially similar images from the same
1873 site. For a more extensive explanation of <quote>patterns</quote>, and
1874 the entire actions concept, see <link linkend="actions-file">the Actions
1879 For advanced users who want to hand edit their config files, you might want
1880 to now go to the <link linkend="act-examples">Actions Files Tutorial</link>.
1881 The ideas explained therein also apply to the web-based editor.
1884 There are also various
1885 <link linkend="filter">filters</link> that can be used for ad blocking
1886 (filters are a special subset of actions). These
1887 fall into the <quote>advanced</quote> usage category, and are explained in
1888 depth in later sections.
1895 <!-- ~ End section ~ -->
1898 <!-- ~~~~~ New section ~~~~~ -->
1899 <sect1 id="startup">
1900 <title>Starting Privoxy</title>
1902 Before launching <application>Privoxy</application> for the first time, you
1903 will want to configure your browser(s) to use
1904 <application>Privoxy</application> as a HTTP and HTTPS (SSL)
1905 <ulink url="http://en.wikipedia.org/wiki/Proxy_server">proxy</ulink>. The default is
1906 127.0.0.1 (or localhost) for the proxy address, and port 8118 (earlier versions
1907 used port 8000). This is the one configuration step <emphasis>that must be done
1911 Please note that <application>Privoxy</application> can only proxy HTTP and
1912 HTTPS traffic. It will not work with FTP or other protocols.
1915 <!-- image of Mozilla Proxy configuration -->
1917 <figure pgwide="0" float="0"><title>Proxy Configuration Showing
1918 Mozilla/Netscape HTTP and HTTPS (SSL) Settings</title>
1921 <imagedata fileref="proxy_setup.jpg" format="jpg">
1924 <phrase>[ Screenshot of Mozilla Proxy Configuration ]</phrase>
1932 With <application>Firefox</application>, this is typically set under:
1936 <guibutton>Tools</guibutton> -> <guibutton>Options</guibutton> -> <guibutton>Advanced</guibutton> -> <guibutton>Network</guibutton> -><guibutton>Connection</guibutton> -> <guibutton>Settings</guibutton>
1941 Or optionally on some platforms:
1945 <guibutton>Edit</guibutton> -> <guibutton>Preferences</guibutton> -> <guibutton>General</guibutton> -> <guibutton>Connection Settings</guibutton> -> <guibutton>Manual Proxy Configuration</guibutton>
1951 With <application>Netscape</application> (and
1952 <application>Mozilla</application>), this can be set under:
1957 <!-- Mix ascii and gui art, something for everybody -->
1958 <!-- spacing on this is tricky -->
1959 <guibutton>Edit</guibutton> -> <guibutton>Preferences</guibutton> -> <guibutton>Advanced</guibutton> -> <guibutton>Proxies</guibutton> -> <guibutton>HTTP Proxy</guibutton>
1964 For <application>Internet Explorer v.5-7</application>:
1968 <guibutton>Tools</guibutton> -> <guibutton>Internet Options</guibutton> -> <guibutton>Connections</guibutton> -> <guibutton>LAN Settings</guibutton>
1972 Then, check <quote>Use Proxy</quote> and fill in the appropriate info
1973 (Address: 127.0.0.1, Port: 8118). Include HTTPS (SSL), if you want HTTPS
1974 proxy support too (sometimes labeled <quote>Secure</quote>). Make sure any
1975 checkboxes like <quote>Use the same proxy server for all protocols</quote> is
1976 <emphasis>UNCHECKED</emphasis>. You want only HTTP and HTTPS (SSL)!
1979 <!-- image of IE Proxy configuration -->
1981 <figure pgwide="0" float="0"><title>Proxy Configuration Showing
1982 Internet Explorer HTTP and HTTPS (Secure) Settings</title>
1985 <imagedata fileref="proxy2.jpg" format="jpg">
1988 <phrase>[ Screenshot of IE Proxy Configuration ]</phrase>
1996 After doing this, flush your browser's disk and memory caches to force a
1997 re-reading of all pages and to get rid of any ads that may be cached. Remove
1998 any <ulink url="http://en.wikipedia.org/wiki/Browser_cookie">cookies</ulink>,
1999 if you want <application>Privoxy</application> to manage that. You are now
2000 ready to start enjoying the benefits of using
2001 <application>Privoxy</application>!
2005 <application>Privoxy</application> itself is typically started by specifying the
2006 main configuration file to be used on the command line. If no configuration
2007 file is specified on the command line, <application>Privoxy</application>
2008 will look for a file named <filename>config</filename> in the current
2009 directory. Except on Win32 where it will try <filename>config.txt</filename>.
2012 <sect2 id="start-redhat">
2013 <title>Red Hat and Fedora</title>
2015 A default Red Hat installation may not start &my-app; upon boot. It will use
2016 the file <filename>/etc/privoxy/config</filename> as its main configuration
2021 # /etc/rc.d/init.d/privoxy start
2029 # service privoxy start
2034 <sect2 id="start-debian">
2035 <title>Debian</title>
2037 We use a script. Note that Debian typically starts &my-app; upon booting per
2038 default. It will use the file
2039 <filename>/etc/privoxy/config</filename> as its main configuration
2044 # /etc/init.d/privoxy start
2049 <sect2 id="start-windows">
2050 <title>Windows</title>
2052 Click on the &my-app; Icon to start <application>Privoxy</application>. If no configuration file is
2053 specified on the command line, <application>Privoxy</application> will look
2054 for a file named <filename>config.txt</filename>. Note that Windows will
2055 automatically start &my-app; when the system starts if you chose that option
2059 <application>Privoxy</application> can run with full Windows service functionality.
2060 On Windows only, the &my-app; program has two new command line arguments
2061 to install and uninstall &my-app; as a service. See the
2062 <link linkend="installation-pack-win">Windows Installation
2063 instructions</link> for details.
2067 <sect2 id="start-unices">
2068 <title>Solaris, NetBSD, FreeBSD, HP-UX and others</title>
2070 Example Unix startup command:
2074 # /usr/sbin/privoxy /etc/privoxy/config
2079 <sect2 id="start-os2">
2082 During installation, <application>Privoxy</application> is configured to
2083 start automatically when the system restarts. You can start it manually by
2084 double-clicking on the <application>Privoxy</application> icon in the
2085 <application>Privoxy</application> folder.
2089 <sect2 id="start-macosx">
2090 <title>Mac OS X</title>
2092 After downloading the privoxy software, unzip the downloaded file by
2093 double-clicking on the zip file icon. Then, double-click on the
2094 installer package icon and follow the installation process.
2097 The privoxy service will automatically start after a successful
2098 installation. In addition, the privoxy service will automatically
2099 start every time your computer starts up.
2102 To prevent the privoxy service from automatically starting when your
2103 computer starts up, remove or rename the folder named
2104 /Library/StartupItems/Privoxy.
2107 A simple application named Privoxy Utility has been created which
2108 enables administrators to easily start and stop the privoxy service.
2111 In addition, the Privoxy Utility presents a simple way for
2112 administrators to edit the various privoxy config files. A method
2113 to uninstall the software is also available.
2116 An administrator username and password must be supplied in order for
2117 the Privoxy Utility to perform any of the tasks.
2122 <sect2 id="start-amigaos">
2123 <title>AmigaOS</title>
2125 Start <application>Privoxy</application> (with RUN <>NIL:) in your
2126 <filename>startnet</filename> script (AmiTCP), in
2127 <filename>s:user-startup</filename> (RoadShow), as startup program in your
2128 startup script (Genesis), or as startup action (Miami and MiamiDx).
2129 <application>Privoxy</application> will automatically quit when you quit your
2130 TCP/IP stack (just ignore the harmless warning your TCP/IP stack may display that
2131 <application>Privoxy</application> is still running).
2135 <sect2 id="start-gentoo">
2136 <title>Gentoo</title>
2138 A script is again used. It will use the file <filename>/etc/privoxy/config
2139 </filename> as its main configuration file.
2143 /etc/init.d/privoxy start
2147 Note that <application>Privoxy</application> is not automatically started at
2148 boot time by default. You can change this with the <literal>rc-update</literal>
2153 rc-update add privoxy default
2161 See the section <link linkend="cmdoptions">Command line options</link> for
2165 must find a better place for this paragraph
2168 The included default configuration files should give a reasonable starting
2169 point. Most of the per site configuration is done in the
2170 <ulink url="actions-file.html"><quote>actions</quote></ulink> files. These are
2171 where various cookie actions are defined, ad and banner blocking, and other
2172 aspects of <application>Privoxy</application> configuration. There are several
2173 such files included, with varying levels of aggressiveness.
2177 You will probably want to keep an eye out for sites for which you may prefer
2178 persistent cookies, and add these to your actions configuration as needed. By
2179 default, most of these will be accepted only during the current browser
2180 session (aka <quote>session cookies</quote>), unless you add them to the
2181 configuration. If you want the browser to handle this instead, you will need
2182 to edit <filename>user.action</filename> (or through the web based interface)
2183 and disable this feature. If you use more than one browser, it would make
2184 more sense to let <application>Privoxy</application> handle this. In which
2185 case, the browser(s) should be set to accept all cookies.
2189 Another feature where you will probably want to define exceptions for trusted
2190 sites is the popup-killing (through <ulink
2191 url="actions-file.html#FILTER-POPUPS"><quote>+filter{popups}</quote></ulink>),
2192 because your favorite shopping, banking, or leisure site may need
2193 popups (explained below).
2197 <application>Privoxy</application> does not support all of the optional HTTP/1.1
2198 features yet. In the unlikely event that you experience inexplicable problems
2199 with browsers that use HTTP/1.1 per default
2200 (like <application>Mozilla</application> or recent versions of I.E.), you might
2201 try to force HTTP/1.0 compatibility. For Mozilla, look under <literal>Edit ->
2202 Preferences -> Debug -> Networking</literal>.
2203 Alternatively, set the <quote>+downgrade-http-version</quote> config option in
2204 <filename>default.action</filename> which will downgrade your browser's HTTP
2205 requests from HTTP/1.1 to HTTP/1.0 before processing them.
2209 After running <application>Privoxy</application> for a while, you can
2210 start to fine tune the configuration to suit your personal, or site,
2211 preferences and requirements. There are many, many aspects that can
2212 be customized. <quote>Actions</quote>
2213 can be adjusted by pointing your browser to
2214 <ulink url="http://config.privoxy.org/">http://config.privoxy.org/</ulink>
2215 (shortcut: <ulink url="http://p.p/">http://p.p/</ulink>),
2216 and then follow the link to <quote>View & Change the Current Configuration</quote>.
2217 (This is an internal page and does not require Internet access.)
2221 In fact, various aspects of <application>Privoxy</application>
2222 configuration can be viewed from this page, including
2223 current configuration parameters, source code version numbers,
2224 the browser's request headers, and <quote>actions</quote> that apply
2225 to a given URL. In addition to the actions file
2226 editor mentioned above, <application>Privoxy</application> can also
2227 be turned <quote>on</quote> and <quote>off</quote> (toggled) from this page.
2231 If you encounter problems, try loading the page without
2232 <application>Privoxy</application>. If that helps, enter the URL where
2233 you have the problems into <ulink url="http://p.p/show-url-info">the browser
2234 based rule tracing utility</ulink>. See which rules apply and why, and
2235 then try turning them off for that site one after the other, until the problem
2236 is gone. When you have found the culprit, you might want to turn the rest on
2241 If the above paragraph sounds gibberish to you, you might want to <link
2242 linkend="actions-file">read more about the actions concept</link>
2243 or even dive deep into the <link linkend="actionsanat">Appendix
2248 If you can't get rid of the problem at all, think you've found a bug in
2249 Privoxy, want to propose a new feature or smarter rules, please see the
2250 section <link linkend="contact"><quote>Contacting the
2251 Developers</quote></link> below.
2256 <!-- ~~~~~ New section ~~~~~ -->
2257 <sect2 id="cmdoptions">
2258 <title>Command Line Options</title>
2260 <application>Privoxy</application> may be invoked with the following
2261 command-line options:
2269 <emphasis>--config-test</emphasis>
2272 Exit after loading the configuration files before binding to
2273 the listen address. The exit code signals whether or not the
2274 configuration files have been successfully loaded.
2277 If the exit code is 1, at least one of the configuration files
2278 is invalid, if it is 0, all the configuration files have been
2279 successfully loaded (but may still contain errors that can
2280 currently only be detected at run time).
2283 This option doesn't affect the log setting, combination with
2284 <emphasis>--no-daemon</emphasis> is recommended if a configured
2285 log file shouldn't be used.
2290 <emphasis>--version</emphasis>
2293 Print version info and exit. Unix only.
2298 <emphasis>--help</emphasis>
2301 Print short usage info and exit. Unix only.
2306 <emphasis>--no-daemon</emphasis>
2309 Don't become a daemon, i.e. don't fork and become process group
2310 leader, and don't detach from controlling tty. Unix only.
2315 <emphasis>--pidfile FILE</emphasis>
2318 On startup, write the process ID to <emphasis>FILE</emphasis>. Delete the
2319 <emphasis>FILE</emphasis> on exit. Failure to create or delete the
2320 <emphasis>FILE</emphasis> is non-fatal. If no <emphasis>FILE</emphasis>
2321 option is given, no PID file will be used. Unix only.
2326 <emphasis>--user USER[.GROUP]</emphasis>
2329 After (optionally) writing the PID file, assume the user ID of
2330 <emphasis>USER</emphasis>, and if included the GID of GROUP. Exit if the
2331 privileges are not sufficient to do so. Unix only.
2336 <emphasis>--chroot</emphasis>
2339 Before changing to the user ID given in the <emphasis>--user</emphasis> option,
2340 chroot to that user's home directory, i.e. make the kernel pretend to the &my-app;
2341 process that the directory tree starts there. If set up carefully, this can limit
2342 the impact of possible vulnerabilities in &my-app; to the files contained in that hierarchy.
2348 <emphasis>--pre-chroot-nslookup hostname</emphasis>
2351 Specifies a hostname to look up before doing a chroot. On some systems, initializing the
2352 resolver library involves reading config files from /etc and/or loading additional shared
2353 libraries from /lib. On these systems, doing a hostname lookup before the chroot reduces
2354 the number of files that must be copied into the chroot tree.
2357 For fastest startup speed, a good value is a hostname that is not in /etc/hosts but that
2358 your local name server (listed in /etc/resolv.conf) can resolve without recursion
2359 (that is, without having to ask any other name servers). The hostname need not exist,
2360 but if it doesn't, an error message (which can be ignored) will be output.
2366 <emphasis>configfile</emphasis>
2369 If no <emphasis>configfile</emphasis> is included on the command line,
2370 <application>Privoxy</application> will look for a file named
2371 <quote>config</quote> in the current directory (except on Win32
2372 where it will look for <quote>config.txt</quote> instead). Specify
2373 full path to avoid confusion. If no config file is found,
2374 <application>Privoxy</application> will fail to start.
2382 On <application>MS Windows</application> only there are two additional
2383 command-line options to allow <application>Privoxy</application> to install and
2384 run as a <emphasis>service</emphasis>. See the
2385 <link linkend="installation-pack-win">Window Installation section</link>
2393 <!-- ~ End section ~ -->
2396 <!-- ~~~~~ New section ~~~~~ -->
2397 <sect1 id="configuration"><title>Privoxy Configuration</title>
2399 All <application>Privoxy</application> configuration is stored
2400 in text files. These files can be edited with a text editor.
2401 Many important aspects of <application>Privoxy</application> can
2402 also be controlled easily with a web browser.
2406 <!-- ~~~~~ New section ~~~~~ -->
2409 <title>Controlling Privoxy with Your Web Browser</title>
2411 <application>Privoxy</application>'s user interface can be reached through the special
2412 URL <ulink url="http://config.privoxy.org/">http://config.privoxy.org/</ulink>
2413 (shortcut: <ulink url="http://p.p/">http://p.p/</ulink>),
2414 which is a built-in page and works without Internet access.
2415 You will see the following section:
2419 <!-- Needs to be put in a table and colorized -->
2422 <bridgehead renderas="sect2"> Privoxy Menu</bridgehead>
2426 ▪ <ulink url="http://config.privoxy.org/show-status">View & change the current configuration</ulink>
2429 ▪ <ulink url="http://config.privoxy.org/show-version">View the source code version numbers</ulink>
2432 ▪ <ulink url="http://config.privoxy.org/show-request">View the request headers.</ulink>
2435 ▪ <ulink url="http://config.privoxy.org/show-url-info">Look up which actions apply to a URL and why</ulink>
2438 ▪ <ulink url="http://config.privoxy.org/toggle">Toggle Privoxy on or off</ulink>
2441 ▪ <ulink
2442 url="http://www.privoxy.org/&p-version;/user-manual/">Documentation</ulink>
2450 This should be self-explanatory. Note the first item leads to an editor for the
2451 <link linkend="actions-file">actions files</link>, which is where the ad, banner,
2452 cookie, and URL blocking magic is configured as well as other advanced features of
2453 <application>Privoxy</application>. This is an easy way to adjust various
2454 aspects of <application>Privoxy</application> configuration. The actions
2455 file, and other configuration files, are explained in detail below.
2459 <quote>Toggle Privoxy On or Off</quote> is handy for sites that might
2460 have problems with your current actions and filters. You can in fact use
2461 it as a test to see whether it is <application>Privoxy</application>
2462 causing the problem or not. <application>Privoxy</application> continues
2463 to run as a proxy in this case, but all manipulation is disabled, i.e.
2464 <application>Privoxy</application> acts like a normal forwarding proxy. There
2465 is even a toggle <link linkend="bookmarklets">Bookmarklet</link> offered, so
2466 that you can toggle <application>Privoxy</application> with one click from
2471 Note that several of the features described above are disabled by default
2472 in <application>Privoxy</application> 3.0.7 beta and later.
2474 <ulink url="config.html">configuration file</ulink> to learn why
2475 and in which cases it's safe to enable them again.
2480 <!-- ~ End section ~ -->
2485 <!-- ~~~~~ New section ~~~~~ -->
2487 <sect2 id="confoverview">
2488 <title>Configuration Files Overview</title>
2490 For Unix, *BSD and Linux, all configuration files are located in
2491 <filename>/etc/privoxy/</filename> by default. For MS Windows, OS/2, and
2492 AmigaOS these are all in the same directory as the
2493 <application>Privoxy</application> executable. <![%p-not-stable;[ The name
2494 and number of configuration files has changed from previous versions, and is
2495 subject to change as development progresses.]]>
2499 The installed defaults provide a reasonable starting point, though
2500 some settings may be aggressive by some standards. For the time being, the
2501 principle configuration files are:
2509 The <link linkend="config">main configuration file</link> is named <filename>config</filename>
2510 on Linux, Unix, BSD, OS/2, and AmigaOS and <filename>config.txt</filename>
2511 on Windows. This is a required file.
2517 <filename>match-all.action</filename> is used to define which <quote>actions</quote>
2518 relating to banner-blocking, images, pop-ups, content modification, cookie handling
2519 etc should be applied by default. It should be the first actions file loaded.
2522 <filename>default.action</filename> defines many exceptions (both positive and negative)
2523 from the default set of actions that's configured in <filename>match-all.action</filename>.
2524 It should be the second actions file loaded and shouldn't be edited by the user.
2527 Multiple actions files may be defined in <filename>config</filename>. These
2528 are processed in the order they are defined. Local customizations and locally
2529 preferred exceptions to the default policies as defined in
2530 <filename>match-all.action</filename> (which you will most probably want
2531 to define sooner or later) are best applied in <filename>user.action</filename>,
2532 where you can preserve them across upgrades. The file isn't installed by all
2533 installers, but you can easily create it yourself with a text editor.
2536 There is also a web based editor that can be accessed from
2538 url="http://config.privoxy.org/show-status">http://config.privoxy.org/show-status</ulink>
2540 url="http://p.p/show-status">http://p.p/show-status</ulink>) for the
2541 various actions files.
2547 <quote>Filter files</quote> (the <link linkend="filter-file">filter
2548 file</link>) can be used to re-write the raw page content, including
2549 viewable text as well as embedded HTML and JavaScript, and whatever else
2550 lurks on any given web page. The filtering jobs are only pre-defined here;
2551 whether to apply them or not is up to the actions files.
2552 <filename>default.filter</filename> includes various filters made
2553 available for use by the developers. Some are much more intrusive than
2554 others, and all should be used with caution. You may define additional
2555 filter files in <filename>config</filename> as you can with
2556 actions files. We suggest <filename>user.filter</filename> for any
2557 locally defined filters or customizations.
2565 The syntax of the configuration and filter files may change between different
2566 Privoxy versions, unfortunately some enhancements cost backwards compatibility.
2567 <!-- Add link to documentation-->
2571 All files use the <quote><literal>#</literal></quote> character to denote a
2572 comment (the rest of the line will be ignored) and understand line continuation
2573 through placing a backslash ("<literal>\</literal>") as the very last character
2574 in a line. If the <literal>#</literal> is preceded by a backslash, it looses
2575 its special function. Placing a <literal>#</literal> in front of an otherwise
2576 valid configuration line to prevent it from being interpreted is called "commenting
2577 out" that line. Blank lines are ignored.
2581 The actions files and filter files
2582 can use Perl style <link linkend="regex">regular expressions</link> for
2583 maximum flexibility.
2587 After making any changes, there is no need to restart
2588 <application>Privoxy</application> in order for the changes to take
2589 effect. <application>Privoxy</application> detects such changes
2590 automatically. Note, however, that it may take one or two additional
2591 requests for the change to take effect. When changing the listening address
2592 of <application>Privoxy</application>, these <quote>wake up</quote> requests
2593 must obviously be sent to the <emphasis>old</emphasis> listening address.
2598 While under development, the configuration content is subject to change.
2599 The below documentation may not be accurate by the time you read this.
2600 Also, what constitutes a <quote>default</quote> setting, may change, so
2601 please check all your configuration files on important issues.
2607 <!-- ~ End section ~ -->
2610 <!-- ~~~~~~~~ New section Header ~~~~~~~~~ -->
2612 <!-- **************************************************** -->
2613 <!-- Include config.sgml here -->
2614 <!-- This is where the entire config file is detailed. -->
2616 <!-- end include -->
2619 <!-- ~ End section ~ -->
2623 <!-- ~~~~~~~~ New section Header ~~~~~~~~~ -->
2625 <sect1 id="actions-file"><title>Actions Files</title>
2629 XXX: similar descriptions are in the Configuration Files sections.
2630 We should only describe them at one place.
2633 The actions files are used to define what <emphasis>actions</emphasis>
2634 <application>Privoxy</application> takes for which URLs, and thus determines
2635 how ad images, cookies and various other aspects of HTTP content and
2636 transactions are handled, and on which sites (or even parts thereof).
2637 There are a number of such actions, with a wide range of functionality.
2638 Each action does something a little different.
2639 These actions give us a veritable arsenal of tools with which to exert
2640 our control, preferences and independence. Actions can be combined so that
2641 their effects are aggregated when applied against a given set of URLs.
2645 are three action files included with <application>Privoxy</application> with
2652 <filename>match-all.action</filename> - is used to define which
2653 <quote>actions</quote> relating to banner-blocking, images, pop-ups,
2654 content modification, cookie handling etc should be applied by default.
2655 It should be the first actions file loaded
2660 <filename>default.action</filename> - defines many exceptions (both
2661 positive and negative) from the default set of actions that's configured
2662 in <filename>match-all.action</filename>. It is a set of rules that should
2663 work reasonably well as-is for most users. This file is only supposed to
2664 be edited by the developers. It should be the second actions file loaded.
2669 <filename>user.action</filename> - is intended to be for local site
2670 preferences and exceptions. As an example, if your ISP or your bank
2671 has specific requirements, and need special handling, this kind of
2672 thing should go here. This file will not be upgraded.
2677 <guibutton>Edit</guibutton> <guibutton>Set to Cautious</guibutton> <guibutton>Set to Medium</guibutton> <guibutton>Set to Advanced</guibutton>
2680 These have increasing levels of aggressiveness <emphasis>and have no
2681 influence on your browsing unless you select them explicitly in the
2682 editor</emphasis>. A default installation should be pre-set to
2683 <literal>Cautious</literal>. New users should try this for a while before
2684 adjusting the settings to more aggressive levels. The more aggressive
2685 the settings, then the more likelihood there is of problems such as sites
2686 not working as they should.
2689 The <guibutton>Edit</guibutton> button allows you to turn each
2690 action on/off individually for fine-tuning. The <guibutton>Cautious</guibutton>
2691 button changes the actions list to low/safe settings which will activate
2692 ad blocking and a minimal set of &my-app;'s features, and subsequently
2693 there will be less of a chance for accidental problems. The
2694 <guibutton>Medium</guibutton> button sets the list to a medium level of
2695 other features and a low level set of privacy features. The
2696 <guibutton>Advanced</guibutton> button sets the list to a high level of
2697 ad blocking and medium level of privacy. See the chart below. The latter
2698 three buttons over-ride any changes via with the
2699 <guibutton>Edit</guibutton> button. More fine-tuning can be done in the
2700 lower sections of this internal page.
2703 While the actions file editor allows to enable these settings in all
2704 actions files, they are only supposed to be enabled in the first one
2705 to make sure you don't unintentionally overrule earlier rules.
2708 The default profiles, and their associated actions, as pre-defined in
2709 <filename>default.action</filename> are:
2712 <table frame=all><title>Default Configurations</title>
2713 <tgroup cols=4 align=left colsep=1 rowsep=1>
2714 <colspec colname=c1>
2715 <colspec colname=c2>
2716 <colspec colname=c3>
2717 <colspec colname=c4>
2720 <entry>Feature</entry>
2721 <entry>Cautious</entry>
2722 <entry>Medium</entry>
2723 <entry>Advanced</entry>
2728 <!-- <entry>f1</entry> -->
2729 <!-- <entry>f2</entry> -->
2730 <!-- <entry>f3</entry> -->
2731 <!-- <entry>f4</entry> -->
2737 <entry>Ad-blocking Aggressiveness</entry>
2738 <entry>medium</entry>
2744 <entry>Ad-filtering by size</entry>
2751 <entry>Ad-filtering by link</entry>
2757 <entry>Pop-up killing</entry>
2758 <entry>blocks only</entry>
2759 <entry>blocks only</entry>
2760 <entry>blocks only</entry>
2764 <entry>Privacy Features</entry>
2766 <entry>medium</entry>
2767 <entry>medium/high</entry>
2771 <entry>Cookie handling</entry>
2773 <entry>session-only</entry>
2778 <entry>Referer forging</entry>
2785 <entry>GIF de-animation</entry>
2792 <entry>Fast redirects</entry>
2799 <entry>HTML taming</entry>
2806 <entry>JavaScript taming</entry>
2813 <entry>Web-bug killing</entry>
2820 <entry>Image tag reordering</entry>
2836 The list of actions files to be used are defined in the main configuration
2837 file, and are processed in the order they are defined (e.g.
2838 <filename>default.action</filename> is typically processed before
2839 <filename>user.action</filename>). The content of these can all be viewed and
2841 url="http://config.privoxy.org/show-status">http://config.privoxy.org/show-status</ulink>.
2842 The over-riding principle when applying actions, is that the last action that
2843 matches a given URL wins. The broadest, most general rules go first
2844 (defined in <filename>default.action</filename>),
2845 followed by any exceptions (typically also in
2846 <filename>default.action</filename>), which are then followed lastly by any
2847 local preferences (typically in <emphasis>user</emphasis><filename>.action</filename>).
2848 Generally, <filename>user.action</filename> has the last word.
2852 An actions file typically has multiple sections. If you want to use
2853 <quote>aliases</quote> in an actions file, you have to place the (optional)
2854 <link linkend="aliases">alias section</link> at the top of that file.
2855 Then comes the default set of rules which will apply universally to all
2856 sites and pages (be <emphasis>very careful</emphasis> with using such a
2857 universal set in <filename>user.action</filename> or any other actions file after
2858 <filename>default.action</filename>, because it will override the result
2859 from consulting any previous file). And then below that,
2860 exceptions to the defined universal policies. You can regard
2861 <filename>user.action</filename> as an appendix to <filename>default.action</filename>,
2862 with the advantage that it is a separate file, which makes preserving your
2863 personal settings across <application>Privoxy</application> upgrades easier.
2867 Actions can be used to block anything you want, including ads, banners, or
2868 just some obnoxious URL whose content you would rather not see. Cookies can be accepted
2869 or rejected, or accepted only during the current browser session (i.e. not
2870 written to disk), content can be modified, some JavaScripts tamed, user-tracking
2871 fooled, and much more. See below for a <link linkend="actions">complete list
2875 <!-- ~~~~~ New section ~~~~~ -->
2877 <title>Finding the Right Mix</title>
2879 Note that some <link linkend="actions">actions</link>, like cookie suppression
2880 or script disabling, may render some sites unusable that rely on these
2881 techniques to work properly. Finding the right mix of actions is not always easy and
2882 certainly a matter of personal taste. And, things can always change, requiring
2883 refinements in the configuration. In general, it can be said that the more
2884 <quote>aggressive</quote> your default settings (in the top section of the
2885 actions file) are, the more exceptions for <quote>trusted</quote> sites you
2886 will have to make later. If, for example, you want to crunch all cookies per
2887 default, you'll have to make exceptions from that rule for sites that you
2888 regularly use and that require cookies for actually useful purposes, like maybe
2889 your bank, favorite shop, or newspaper.
2893 We have tried to provide you with reasonable rules to start from in the
2894 distribution actions files. But there is no general rule of thumb on these
2895 things. There just are too many variables, and sites are constantly changing.
2896 Sooner or later you will want to change the rules (and read this chapter again :).
2900 <!-- ~~~~~ New section ~~~~~ -->
2902 <title>How to Edit</title>
2904 The easiest way to edit the actions files is with a browser by
2905 using our browser-based editor, which can be reached from <ulink
2906 url="http://config.privoxy.org/show-status">http://config.privoxy.org/show-status</ulink>.
2907 Note: the config file option <link
2908 linkend="enable-edit-actions">enable-edit-actions</link> must be enabled for
2909 this to work. The editor allows both fine-grained control over every single
2910 feature on a per-URL basis, and easy choosing from wholesale sets of defaults
2911 like <quote>Cautious</quote>, <quote>Medium</quote> or
2912 <quote>Advanced</quote>. Warning: the <quote>Advanced</quote> setting is more
2913 aggressive, and will be more likely to cause problems for some sites.
2914 Experienced users only!
2918 If you prefer plain text editing to GUIs, you can of course also directly edit the
2919 the actions files with your favorite text editor. Look at
2920 <filename>default.action</filename> which is richly commented with many
2926 <sect2 id="actions-apply">
2927 <title>How Actions are Applied to Requests</title>
2929 Actions files are divided into sections. There are special sections,
2930 like the <quote><link linkend="aliases">alias</link></quote> sections which will
2931 be discussed later. For now let's concentrate on regular sections: They have a
2932 heading line (often split up to multiple lines for readability) which consist
2933 of a list of actions, separated by whitespace and enclosed in curly braces.
2934 Below that, there is a list of URL and tag patterns, each on a separate line.
2938 To determine which actions apply to a request, the URL of the request is
2939 compared to all URL patterns in each <quote>action file</quote>.
2940 Every time it matches, the list of applicable actions for the request is
2941 incrementally updated, using the heading of the section in which the
2942 pattern is located. The same is done again for tags and tag patterns later on.
2946 If multiple applying sections set the same action differently,
2947 the last match wins. If not, the effects are aggregated.
2948 E.g. a URL might match a regular section with a heading line of <literal>{
2949 +<link linkend="handle-as-image">handle-as-image</link> }</literal>,
2950 then later another one with just <literal>{
2951 +<link linkend="block">block</link> }</literal>, resulting
2952 in <emphasis>both</emphasis> actions to apply. And there may well be
2953 cases where you will want to combine actions together. Such a section then
2959 { +<literal>handle-as-image</literal> +<literal>block{Banner ads.}</literal> }
2960 # Block these as if they were images. Send no block page.
2962 media.example.com/.*banners
2963 .example.com/images/ads/</screen>
2967 You can trace this process for URL patterns and any given URL by visiting <ulink
2968 url="http://config.privoxy.org/show-url-info">http://config.privoxy.org/show-url-info</ulink>.
2972 Examples and more detail on this is provided in the Appendix, <link linkend="ACTIONSANAT">
2973 Troubleshooting: Anatomy of an Action</link> section.
2977 <!-- ~~~~~ New section ~~~~~ -->
2978 <sect2 id="af-patterns">
2979 <title>Patterns</title>
2981 As mentioned, <application>Privoxy</application> uses <quote>patterns</quote>
2982 to determine what <emphasis>actions</emphasis> might apply to which sites and
2983 pages your browser attempts to access. These <quote>patterns</quote> use wild
2984 card type <emphasis>pattern</emphasis> matching to achieve a high degree of
2985 flexibility. This allows one expression to be expanded and potentially match
2986 against many similar patterns.
2990 Generally, an URL pattern has the form
2991 <literal><domain><port>/<path></literal>, where the
2992 <literal><domain></literal>, the <literal><port></literal>
2993 and the <literal><path></literal> are optional. (This is why the special
2994 <literal>/</literal> pattern matches all URLs). Note that the protocol
2995 portion of the URL pattern (e.g. <literal>http://</literal>) should
2996 <emphasis>not</emphasis> be included in the pattern. This is assumed already!
2999 The pattern matching syntax is different for the domain and path parts of
3000 the URL. The domain part uses a simple globbing type matching technique,
3001 while the path part uses more flexible
3002 <ulink url="http://en.wikipedia.org/wiki/Regular_expressions"><quote>Regular
3003 Expressions</quote></ulink> (POSIX 1003.2).
3006 The port part of a pattern is a decimal port number preceded by a colon
3007 (<literal>:</literal>). If the domain part contains a numerical IPv6 address,
3008 it has to be put into angle brackets
3009 (<literal><</literal>, <literal>></literal>).
3014 <term><literal>www.example.com/</literal></term>
3017 is a domain-only pattern and will match any request to <literal>www.example.com</literal>,
3018 regardless of which document on that server is requested. So ALL pages in
3019 this domain would be covered by the scope of this action. Note that a
3020 simple <literal>example.com</literal> is different and would NOT match.
3025 <term><literal>www.example.com</literal></term>
3028 means exactly the same. For domain-only patterns, the trailing <literal>/</literal> may
3034 <term><literal>www.example.com/index.html</literal></term>
3037 matches all the documents on <literal>www.example.com</literal>
3038 whose name starts with <literal>/index.html</literal>.
3043 <term><literal>www.example.com/index.html$</literal></term>
3046 matches only the single document <literal>/index.html</literal>
3047 on <literal>www.example.com</literal>.
3052 <term><literal>/index.html$</literal></term>
3055 matches the document <literal>/index.html</literal>, regardless of the domain,
3056 i.e. on <emphasis>any</emphasis> web server anywhere.
3061 <term><literal>/</literal></term>
3064 Matches any URL because there's no requirement for either the
3065 domain or the path to match anything.
3070 <term><literal>:8000/</literal></term>
3073 Matches any URL pointing to TCP port 8000.
3078 <term><literal><2001:db8::1>/</literal></term>
3081 Matches any URL with the host address <literal>2001:db8::1</literal>.
3082 (Note that the real URL uses plain brackets, not angle brackets.)
3087 <term><literal>index.html</literal></term>
3090 matches nothing, since it would be interpreted as a domain name and
3091 there is no top-level domain called <literal>.html</literal>. So its
3099 <!-- ~~~~~ New section ~~~~~ -->
3100 <sect3><title>The Domain Pattern</title>
3103 The matching of the domain part offers some flexible options: if the
3104 domain starts or ends with a dot, it becomes unanchored at that end.
3110 <term><literal>.example.com</literal></term>
3113 matches any domain with first-level domain <literal>com</literal>
3114 and second-level domain <literal>example</literal>.
3115 For example <literal>www.example.com</literal>,
3116 <literal>example.com</literal> and <literal>foo.bar.baz.example.com</literal>.
3117 Note that it wouldn't match if the second-level domain was <literal>another-example</literal>.
3122 <term><literal>www.</literal></term>
3125 matches any domain that <emphasis>STARTS</emphasis> with
3126 <literal>www.</literal> (It also matches the domain
3127 <literal>www</literal> but most of the time that doesn't matter.)
3132 <term><literal>.example.</literal></term>
3135 matches any domain that <emphasis>CONTAINS</emphasis> <literal>.example.</literal>.
3136 And, by the way, also included would be any files or documents that exist
3137 within that domain since no path limitations are specified. (Correctly
3138 speaking: It matches any FQDN that contains <literal>example</literal> as
3139 a domain.) This might be <literal>www.example.com</literal>,
3140 <literal>news.example.de</literal>, or
3141 <literal>www.example.net/cgi/testing.pl</literal> for instance. All these
3149 Additionally, there are wild-cards that you can use in the domain names
3150 themselves. These work similarly to shell globbing type wild-cards:
3151 <quote>*</quote> represents zero or more arbitrary characters (this is
3153 <ulink url="http://en.wikipedia.org/wiki/Regular_expressions"><quote>Regular
3154 Expression</quote></ulink> based syntax of <quote>.*</quote>),
3155 <quote>?</quote> represents any single character (this is equivalent to the
3156 regular expression syntax of a simple <quote>.</quote>), and you can define
3157 <quote>character classes</quote> in square brackets which is similar to
3158 the same regular expression technique. All of this can be freely mixed:
3163 <term><literal>ad*.example.com</literal></term>
3166 matches <quote>adserver.example.com</quote>,
3167 <quote>ads.example.com</quote>, etc but not <quote>sfads.example.com</quote>
3172 <term><literal>*ad*.example.com</literal></term>
3175 matches all of the above, and then some.
3180 <term><literal>.?pix.com</literal></term>
3183 matches <literal>www.ipix.com</literal>,
3184 <literal>pictures.epix.com</literal>, <literal>a.b.c.d.e.upix.com</literal> etc.
3189 <term><literal>www[1-9a-ez].example.c*</literal></term>
3192 matches <literal>www1.example.com</literal>,
3193 <literal>www4.example.cc</literal>, <literal>wwwd.example.cy</literal>,
3194 <literal>wwwz.example.com</literal> etc., but <emphasis>not</emphasis>
3195 <literal>wwww.example.com</literal>.
3202 While flexible, this is not the sophistication of full regular expression based syntax.
3207 <!-- ~ End section ~ -->
3210 <!-- ~~~~~ New section ~~~~~ -->
3211 <sect3><title>The Path Pattern</title>
3214 <application>Privoxy</application> uses <quote>modern</quote> POSIX 1003.2
3215 <ulink url="http://en.wikipedia.org/wiki/Regular_expressions"><quote>Regular
3216 Expressions</quote></ulink> for matching the path portion (after the slash),
3217 and is thus more flexible.
3221 There is an <link linkend="regex">Appendix</link> with a brief quick-start into regular
3222 expressions, you also might want to have a look at your operating system's documentation
3223 on regular expressions (try <literal>man re_format</literal>).
3227 Note that the path pattern is automatically left-anchored at the <quote>/</quote>,
3228 i.e. it matches as if it would start with a <quote>^</quote> (regular expression speak
3229 for the beginning of a line).
3233 Please also note that matching in the path is <emphasis>CASE INSENSITIVE</emphasis>
3234 by default, but you can switch to case sensitive at any point in the pattern by using the
3235 <quote>(?-i)</quote> switch: <literal>www.example.com/(?-i)PaTtErN.*</literal> will match
3236 only documents whose path starts with <literal>PaTtErN</literal> in
3237 <emphasis>exactly</emphasis> this capitalization.
3242 <term><literal>.example.com/.*</literal></term>
3245 Is equivalent to just <quote>.example.com</quote>, since any documents
3246 within that domain are matched with or without the <quote>.*</quote>
3247 regular expression. This is redundant
3252 <term><literal>.example.com/.*/index.html$</literal></term>
3255 Will match any page in the domain of <quote>example.com</quote> that is
3256 named <quote>index.html</quote>, and that is part of some path. For
3257 example, it matches <quote>www.example.com/testing/index.html</quote> but
3258 NOT <quote>www.example.com/index.html</quote> because the regular
3259 expression called for at least two <quote>/'s</quote>, thus the path
3260 requirement. It also would match
3261 <quote>www.example.com/testing/index_html</quote>, because of the
3262 special meta-character <quote>.</quote>.
3267 <term><literal>.example.com/(.*/)?index\.html$</literal></term>
3270 This regular expression is conditional so it will match any page
3271 named <quote>index.html</quote> regardless of path which in this case can
3272 have one or more <quote>/'s</quote>. And this one must contain exactly
3273 <quote>.html</quote> (but does not have to end with that!).
3278 <term><literal>.example.com/(.*/)(ads|banners?|junk)</literal></term>
3281 This regular expression will match any path of <quote>example.com</quote>
3282 that contains any of the words <quote>ads</quote>, <quote>banner</quote>,
3283 <quote>banners</quote> (because of the <quote>?</quote>) or <quote>junk</quote>.
3284 The path does not have to end in these words, just contain them.
3289 <term><literal>.example.com/(.*/)(ads|banners?|junk)/.*\.(jpe?g|gif|png)$</literal></term>
3292 This is very much the same as above, except now it must end in either
3293 <quote>.jpg</quote>, <quote>.jpeg</quote>, <quote>.gif</quote> or <quote>.png</quote>. So this
3294 one is limited to common image formats.
3301 There are many, many good examples to be found in <filename>default.action</filename>,
3302 and more tutorials below in <link linkend="regex">Appendix on regular expressions</link>.
3307 <!-- ~ End section ~ -->
3310 <!-- ~~~~~ New section ~~~~~ -->
3311 <sect3 id="tag-pattern"><title>The Tag Pattern</title>
3314 Tag patterns are used to change the applying actions based on the
3315 request's tags. Tags can be created with either the
3316 <link linkend="CLIENT-HEADER-TAGGER">client-header-tagger</link>
3317 or the <link linkend="SERVER-HEADER-TAGGER">server-header-tagger</link> action.
3321 Tag patterns have to start with <quote>TAG:</quote>, so &my-app;
3322 can tell them apart from URL patterns. Everything after the colon
3323 including white space, is interpreted as a regular expression with
3324 path pattern syntax, except that tag patterns aren't left-anchored
3325 automatically (&my-app; doesn't silently add a <quote>^</quote>,
3326 you have to do it yourself if you need it).
3330 To match all requests that are tagged with <quote>foo</quote>
3331 your pattern line should be <quote>TAG:^foo$</quote>,
3332 <quote>TAG:foo</quote> would work as well, but it would also
3333 match requests whose tags contain <quote>foo</quote> somewhere.
3334 <quote>TAG: foo</quote> wouldn't work as it requires white space.
3338 Sections can contain URL and tag patterns at the same time,
3339 but tag patterns are checked after the URL patterns and thus
3340 always overrule them, even if they are located before the URL patterns.
3344 Once a new tag is added, Privoxy checks right away if it's matched by one
3345 of the tag patterns and updates the action settings accordingly. As a result
3346 tags can be used to activate other tagger actions, as long as these other
3347 taggers look for headers that haven't already be parsed.
3351 For example you could tag client requests which use the
3352 <literal>POST</literal> method,
3353 then use this tag to activate another tagger that adds a tag if cookies
3354 are sent, and then use a block action based on the cookie tag. This allows
3355 the outcome of one action, to be input into a subsequent action. However if
3356 you'd reverse the position of the described taggers, and activated the
3357 method tagger based on the cookie tagger, no method tags would be created.
3358 The method tagger would look for the request line, but at the time
3359 the cookie tag is created, the request line has already been parsed.
3363 While this is a limitation you should be aware of, this kind of
3364 indirection is seldom needed anyway and even the example doesn't
3365 make too much sense.
3372 <!-- ~ End section ~ -->
3375 <!-- ~~~~~ New section ~~~~~ -->
3377 <sect2 id="actions">
3378 <title>Actions</title>
3380 All actions are disabled by default, until they are explicitly enabled
3381 somewhere in an actions file. Actions are turned on if preceded with a
3382 <quote>+</quote>, and turned off if preceded with a <quote>-</quote>. So a
3383 <literal>+action</literal> means <quote>do that action</quote>, e.g.
3384 <literal>+block</literal> means <quote>please block URLs that match the
3385 following patterns</quote>, and <literal>-block</literal> means <quote>don't
3386 block URLs that match the following patterns, even if <literal>+block</literal>
3387 previously applied.</quote>
3392 Again, actions are invoked by placing them on a line, enclosed in curly braces and
3393 separated by whitespace, like in
3394 <literal>{+some-action -some-other-action{some-parameter}}</literal>,
3395 followed by a list of URL patterns, one per line, to which they apply.
3396 Together, the actions line and the following pattern lines make up a section
3397 of the actions file.
3401 Actions fall into three categories:
3408 Boolean, i.e the action can only be <quote>enabled</quote> or
3409 <quote>disabled</quote>. Syntax:
3413 +<replaceable class="function">name</replaceable> # enable action <replaceable class="parameter">name</replaceable>
3414 -<replaceable class="function">name</replaceable> # disable action <replaceable class="parameter">name</replaceable></screen>
3417 Example: <literal>+handle-as-image</literal>
3424 Parameterized, where some value is required in order to enable this type of action.
3429 +<replaceable class="function">name</replaceable>{<replaceable class="parameter">param</replaceable>} # enable action and set parameter to <replaceable class="parameter">param</replaceable>,
3430 # overwriting parameter from previous match if necessary
3431 -<replaceable class="function">name</replaceable> # disable action. The parameter can be omitted</screen>
3434 Note that if the URL matches multiple positive forms of a parameterized action,
3435 the last match wins, i.e. the params from earlier matches are simply ignored.
3438 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>
3444 Multi-value. These look exactly like parameterized actions,
3445 but they behave differently: If the action applies multiple times to the
3446 same URL, but with different parameters, <emphasis>all</emphasis> the parameters
3447 from <emphasis>all</emphasis> matches are remembered. This is used for actions
3448 that can be executed for the same request repeatedly, like adding multiple
3449 headers, or filtering through multiple filters. Syntax:
3453 +<replaceable class="function">name</replaceable>{<replaceable class="parameter">param</replaceable>} # enable action and add <replaceable class="parameter">param</replaceable> to the list of parameters
3454 -<replaceable class="function">name</replaceable>{<replaceable class="parameter">param</replaceable>} # remove the parameter <replaceable class="parameter">param</replaceable> from the list of parameters
3455 # If it was the last one left, disable the action.
3456 <replaceable class="parameter">-name</replaceable> # disable this action completely and remove all parameters from the list</screen>
3459 Examples: <literal>+add-header{X-Fun-Header: Some text}</literal> and
3460 <literal>+filter{html-annoyances}</literal>
3468 If nothing is specified in any actions file, no <quote>actions</quote> are
3469 taken. So in this case <application>Privoxy</application> would just be a
3470 normal, non-blocking, non-filtering proxy. You must specifically enable the
3471 privacy and blocking features you need (although the provided default actions
3472 files will give a good starting point).
3476 Later defined action sections always over-ride earlier ones of the same type.
3477 So exceptions to any rules you make, should come in the latter part of the file (or
3478 in a file that is processed later when using multiple actions files such
3479 as <filename>user.action</filename>). For multi-valued actions, the actions
3480 are applied in the order they are specified. Actions files are processed in
3481 the order they are defined in <filename>config</filename> (the default
3482 installation has three actions files). It also quite possible for any given
3483 URL to match more than one <quote>pattern</quote> (because of wildcards and
3484 regular expressions), and thus to trigger more than one set of actions! Last
3488 <!-- start actions listing -->
3490 The list of valid <application>Privoxy</application> actions are:
3494 <!-- ********************************************************** -->
3495 <!-- Please note the below defined actions use id's that are -->
3496 <!-- probably linked from other places, so please don't change. -->
3498 <!-- ********************************************************** -->
3501 <!-- ~~~~~ New section ~~~~~ -->
3503 <sect3 renderas="sect4" id="add-header">
3504 <title>add-header</title>
3508 <term>Typical use:</term>
3510 <para>Confuse log analysis, custom applications</para>
3515 <term>Effect:</term>
3518 Sends a user defined HTTP header to the web server.
3525 <!-- boolean, parameterized, Multi-value -->
3527 <para>Multi-value.</para>
3532 <term>Parameter:</term>
3535 Any string value is possible. Validity of the defined HTTP headers is not checked.
3536 It is recommended that you use the <quote><literal>X-</literal></quote> prefix
3546 This action may be specified multiple times, in order to define multiple
3547 headers. This is rarely needed for the typical user. If you don't know what
3548 <quote>HTTP headers</quote> are, you definitely don't need to worry about this
3552 Headers added by this action are not modified by other actions.
3558 <term>Example usage:</term>
3561 <screen>+add-header{X-User-Tracking: sucks}</screen>
3569 <!-- ~~~~~ New section ~~~~~ -->
3570 <sect3 renderas="sect4" id="block">
3571 <title>block</title>
3575 <term>Typical use:</term>
3577 <para>Block ads or other unwanted content</para>
3582 <term>Effect:</term>
3585 Requests for URLs to which this action applies are blocked, i.e. the
3586 requests are trapped by &my-app; and the requested URL is never retrieved,
3587 but is answered locally with a substitute page or image, as determined by
3589 linkend="handle-as-image">handle-as-image</link></literal>,
3591 linkend="set-image-blocker">set-image-blocker</link></literal>, and
3593 linkend="handle-as-empty-document">handle-as-empty-document</link></literal> actions.
3601 <!-- boolean, parameterized, Multi-value -->
3603 <para>Parameterized.</para>
3608 <term>Parameter:</term>
3610 <para>A block reason that should be given to the user.</para>
3618 <application>Privoxy</application> sends a special <quote>BLOCKED</quote> page
3619 for requests to blocked pages. This page contains the block reason given as
3620 parameter, a link to find out why the block action applies, and a click-through
3621 to the blocked content (the latter only if the force feature is available and
3625 A very important exception occurs if <emphasis>both</emphasis>
3626 <literal>block</literal> and <literal><link linkend="handle-as-image">handle-as-image</link></literal>,
3627 apply to the same request: it will then be replaced by an image. If
3628 <literal><link linkend="set-image-blocker">set-image-blocker</link></literal>
3629 (see below) also applies, the type of image will be determined by its parameter,
3630 if not, the standard checkerboard pattern is sent.
3633 It is important to understand this process, in order
3634 to understand how <application>Privoxy</application> deals with
3635 ads and other unwanted content. Blocking is a core feature, and one
3636 upon which various other features depend.
3639 The <literal><link linkend="filter">filter</link></literal>
3640 action can perform a very similar task, by <quote>blocking</quote>
3641 banner images and other content through rewriting the relevant URLs in the
3642 document's HTML source, so they don't get requested in the first place.
3643 Note that this is a totally different technique, and it's easy to confuse the two.
3649 <term>Example usage (section):</term>
3652 <screen>{+block{No nasty stuff for you.}}
3653 # Block and replace with "blocked" page
3654 .nasty-stuff.example.com
3656 {+block{Doubleclick banners.} +handle-as-image}
3657 # Block and replace with image
3661 {+block{Layered ads.} +handle-as-empty-document}
3662 # Block and then ignore
3663 adserver.example.net/.*\.js$</screen>
3673 <!-- ~~~~~ New section ~~~~~ -->
3674 <sect3 renderas="sect4" id="change-x-forwarded-for">
3675 <title>change-x-forwarded-for</title>
3679 <term>Typical use:</term>
3681 <para>Improve privacy by not forwarding the source of the request in the HTTP headers.</para>
3686 <term>Effect:</term>
3689 Deletes the <quote>X-Forwarded-For:</quote> HTTP header from the client request,
3697 <!-- Boolean, Parameterized, Multi-value -->
3699 <para>Parameterized.</para>
3704 <term>Parameter:</term>
3708 <para><quote>block</quote> to delete the header.</para>
3712 <quote>add</quote> to create the header (or append
3713 the client's IP address to an already existing one).
3724 It is safe and recommended to use <literal>block</literal>.
3727 Forwarding the source address of the request may make
3728 sense in some multi-user setups but is also a privacy risk.
3733 <term>Example usage:</term>
3736 <screen>+change-x-forwarded-for{block}</screen>
3743 <!-- ~~~~~ New section ~~~~~ -->
3744 <sect3 renderas="sect4" id="client-header-filter">
3745 <title>client-header-filter</title>
3749 <term>Typical use:</term>
3752 Rewrite or remove single client headers.
3758 <term>Effect:</term>
3761 All client headers to which this action applies are filtered on-the-fly through
3762 the specified regular expression based substitutions.
3769 <!-- boolean, parameterized, Multi-value -->
3771 <para>Parameterized.</para>
3776 <term>Parameter:</term>
3779 The name of a client-header filter, as defined in one of the
3780 <link linkend="filter-file">filter files</link>.
3789 Client-header filters are applied to each header on its own, not to
3790 all at once. This makes it easier to diagnose problems, but on the downside
3791 you can't write filters that only change header x if header y's value is z.
3792 You can do that by using tags though.
3795 Client-header filters are executed after the other header actions have finished
3796 and use their output as input.
3799 If the request URI gets changed, &my-app; will detect that and use the new
3800 one. This can be used to rewrite the request destination behind the client's
3801 back, for example to specify a Tor exit relay for certain requests.
3804 Please refer to the <link linkend="filter-file">filter file chapter</link>
3805 to learn which client-header filters are available by default, and how to
3813 <term>Example usage (section):</term>
3817 # Hide Tor exit notation in Host and Referer Headers
3818 {+client-header-filter{hide-tor-exit-notation}}
3829 <!-- ~~~~~ New section ~~~~~ -->
3830 <sect3 renderas="sect4" id="client-header-tagger">
3831 <title>client-header-tagger</title>
3835 <term>Typical use:</term>
3838 Block requests based on their headers.
3844 <term>Effect:</term>
3847 Client headers to which this action applies are filtered on-the-fly through
3848 the specified regular expression based substitutions, the result is used as
3856 <!-- boolean, parameterized, Multi-value -->
3858 <para>Parameterized.</para>
3863 <term>Parameter:</term>
3866 The name of a client-header tagger, as defined in one of the
3867 <link linkend="filter-file">filter files</link>.
3876 Client-header taggers are applied to each header on its own,
3877 and as the header isn't modified, each tagger <quote>sees</quote>
3881 Client-header taggers are the first actions that are executed
3882 and their tags can be used to control every other action.
3888 <term>Example usage (section):</term>
3892 # Tag every request with the User-Agent header
3893 {+client-header-tagger{user-agent}}
3896 # Tagging itself doesn't change the action
3897 # settings, sections with TAG patterns do:
3899 # If it's a download agent, use a different forwarding proxy,
3900 # show the real User-Agent and make sure resume works.
3901 {+forward-override{forward-socks5 10.0.0.2:2222 .} \
3902 -hide-if-modified-since \
3903 -overwrite-last-modified \
3908 TAG:^User-Agent: NetBSD-ftp/
3909 TAG:^User-Agent: Novell ZYPP Installer
3910 TAG:^User-Agent: RPM APT-HTTP/
3911 TAG:^User-Agent: fetch libfetch/
3912 TAG:^User-Agent: Ubuntu APT-HTTP/
3913 TAG:^User-Agent: MPlayer/
3918 # Tag all requests with the Range header set
3919 {+client-header-tagger{range-requests}}
3922 # Disable filtering for the tagged requests.
3924 # With filtering enabled Privoxy would remove the Range headers
3925 # to be able to filter the whole response. The downside is that
3926 # it prevents clients from resuming downloads or skipping over
3927 # parts of multimedia files.
3928 {-filter -deanimate-gifs}
3939 <!-- ~~~~~ New section ~~~~~ -->
3940 <sect3 renderas="sect4" id="content-type-overwrite">
3941 <title>content-type-overwrite</title>
3945 <term>Typical use:</term>
3947 <para>Stop useless download menus from popping up, or change the browser's rendering mode</para>
3952 <term>Effect:</term>
3955 Replaces the <quote>Content-Type:</quote> HTTP server header.
3962 <!-- Boolean, Parameterized, Multi-value -->
3964 <para>Parameterized.</para>
3969 <term>Parameter:</term>
3981 The <quote>Content-Type:</quote> HTTP server header is used by the
3982 browser to decide what to do with the document. The value of this
3983 header can cause the browser to open a download menu instead of
3984 displaying the document by itself, even if the document's format is
3985 supported by the browser.
3988 The declared content type can also affect which rendering mode
3989 the browser chooses. If XHTML is delivered as <quote>text/html</quote>,
3990 many browsers treat it as yet another broken HTML document.
3991 If it is send as <quote>application/xml</quote>, browsers with
3992 XHTML support will only display it, if the syntax is correct.
3995 If you see a web site that proudly uses XHTML buttons, but sets
3996 <quote>Content-Type: text/html</quote>, you can use &my-app;
3997 to overwrite it with <quote>application/xml</quote> and validate
3998 the web master's claim inside your XHTML-supporting browser.
3999 If the syntax is incorrect, the browser will complain loudly.
4002 You can also go the opposite direction: if your browser prints
4003 error messages instead of rendering a document falsely declared
4004 as XHTML, you can overwrite the content type with
4005 <quote>text/html</quote> and have it rendered as broken HTML document.
4008 By default <literal>content-type-overwrite</literal> only replaces
4009 <quote>Content-Type:</quote> headers that look like some kind of text.
4010 If you want to overwrite it unconditionally, you have to combine it with
4011 <literal><link linkend="force-text-mode">force-text-mode</link></literal>.
4012 This limitation exists for a reason, think twice before circumventing it.
4015 Most of the time it's easier to replace this action with a custom
4016 <literal><link linkend="server-header-filter">server-header filter</link></literal>.
4017 It allows you to activate it for every document of a certain site and it will still
4018 only replace the content types you aimed at.
4021 Of course you can apply <literal>content-type-overwrite</literal>
4022 to a whole site and then make URL based exceptions, but it's a lot
4023 more work to get the same precision.
4029 <term>Example usage (sections):</term>
4032 <screen># Check if www.example.net/ really uses valid XHTML
4033 { +content-type-overwrite{application/xml} }
4036 # but leave the content type unmodified if the URL looks like a style sheet
4037 {-content-type-overwrite}
4038 www.example.net/.*\.css$
4039 www.example.net/.*style
4048 <!-- ~~~~~ New section ~~~~~ -->
4049 <sect3 renderas="sect4" id="crunch-client-header">
4053 <title>crunch-client-header</title>
4057 <term>Typical use:</term>
4059 <para>Remove a client header <application>Privoxy</application> has no dedicated action for.</para>
4064 <term>Effect:</term>
4067 Deletes every header sent by the client that contains the string the user supplied as parameter.
4074 <!-- Boolean, Parameterized, Multi-value -->
4076 <para>Parameterized.</para>
4081 <term>Parameter:</term>
4093 This action allows you to block client headers for which no dedicated
4094 <application>Privoxy</application> action exists.
4095 <application>Privoxy</application> will remove every client header that
4096 contains the string you supplied as parameter.
4099 Regular expressions are <emphasis>not supported</emphasis> and you can't
4100 use this action to block different headers in the same request, unless
4101 they contain the same string.
4104 <literal>crunch-client-header</literal> is only meant for quick tests.
4105 If you have to block several different headers, or only want to modify
4106 parts of them, you should use a
4107 <literal><link linkend="client-header-filter">client-header filter</link></literal>.
4111 Don't block any header without understanding the consequences.
4118 <term>Example usage (section):</term>
4121 <screen># Block the non-existent "Privacy-Violation:" client header
4122 { +crunch-client-header{Privacy-Violation:} }
4132 <!-- ~~~~~ New section ~~~~~ -->
4133 <sect3 renderas="sect4" id="crunch-if-none-match">
4134 <title>crunch-if-none-match</title>
4140 <term>Typical use:</term>
4142 <para>Prevent yet another way to track the user's steps between sessions.</para>
4147 <term>Effect:</term>
4150 Deletes the <quote>If-None-Match:</quote> HTTP client header.
4157 <!-- Boolean, Parameterized, Multi-value -->
4159 <para>Boolean.</para>
4164 <term>Parameter:</term>
4176 Removing the <quote>If-None-Match:</quote> HTTP client header
4177 is useful for filter testing, where you want to force a real
4178 reload instead of getting status code <quote>304</quote> which
4179 would cause the browser to use a cached copy of the page.
4182 It is also useful to make sure the header isn't used as a cookie
4183 replacement (unlikely but possible).
4186 Blocking the <quote>If-None-Match:</quote> header shouldn't cause any
4187 caching problems, as long as the <quote>If-Modified-Since:</quote> header
4188 isn't blocked or missing as well.
4191 It is recommended to use this action together with
4192 <literal><link linkend="hide-if-modified-since">hide-if-modified-since</link></literal>
4194 <literal><link linkend="overwrite-last-modified">overwrite-last-modified</link></literal>.
4200 <term>Example usage (section):</term>
4203 <screen># Let the browser revalidate cached documents but don't
4204 # allow the server to use the revalidation headers for user tracking.
4205 {+hide-if-modified-since{-60} \
4206 +overwrite-last-modified{randomize} \
4207 +crunch-if-none-match}
4216 <!-- ~~~~~ New section ~~~~~ -->
4217 <sect3 renderas="sect4" id="crunch-incoming-cookies">
4218 <title>crunch-incoming-cookies</title>
4222 <term>Typical use:</term>
4225 Prevent the web server from setting HTTP cookies on your system
4231 <term>Effect:</term>
4234 Deletes any <quote>Set-Cookie:</quote> HTTP headers from server replies.
4241 <!-- Boolean, Parameterized, Multi-value -->
4243 <para>Boolean.</para>
4248 <term>Parameter:</term>
4260 This action is only concerned with <emphasis>incoming</emphasis> HTTP cookies. For
4261 <emphasis>outgoing</emphasis> HTTP cookies, use
4262 <literal><link linkend="crunch-outgoing-cookies">crunch-outgoing-cookies</link></literal>.
4263 Use <emphasis>both</emphasis> to disable HTTP cookies completely.
4266 It makes <emphasis>no sense at all</emphasis> to use this action in conjunction
4267 with the <literal><link linkend="session-cookies-only">session-cookies-only</link></literal> action,
4268 since it would prevent the session cookies from being set. See also
4269 <literal><link linkend="filter-content-cookies">filter-content-cookies</link></literal>.
4275 <term>Example usage:</term>
4278 <screen>+crunch-incoming-cookies</screen>
4286 <!-- ~~~~~ New section ~~~~~ -->
4287 <sect3 renderas="sect4" id="crunch-server-header">
4288 <title>crunch-server-header</title>
4294 <term>Typical use:</term>
4296 <para>Remove a server header <application>Privoxy</application> has no dedicated action for.</para>
4301 <term>Effect:</term>
4304 Deletes every header sent by the server that contains the string the user supplied as parameter.
4311 <!-- Boolean, Parameterized, Multi-value -->
4313 <para>Parameterized.</para>
4318 <term>Parameter:</term>
4330 This action allows you to block server headers for which no dedicated
4331 <application>Privoxy</application> action exists. <application>Privoxy</application>
4332 will remove every server header that contains the string you supplied as parameter.
4335 Regular expressions are <emphasis>not supported</emphasis> and you can't
4336 use this action to block different headers in the same request, unless
4337 they contain the same string.
4340 <literal>crunch-server-header</literal> is only meant for quick tests.
4341 If you have to block several different headers, or only want to modify
4342 parts of them, you should use a custom
4343 <literal><link linkend="server-header-filter">server-header filter</link></literal>.
4347 Don't block any header without understanding the consequences.
4354 <term>Example usage (section):</term>
4357 <screen># Crunch server headers that try to prevent caching
4358 { +crunch-server-header{no-cache} }
4367 <!-- ~~~~~ New section ~~~~~ -->
4368 <sect3 renderas="sect4" id="crunch-outgoing-cookies">
4369 <title>crunch-outgoing-cookies</title>
4373 <term>Typical use:</term>
4376 Prevent the web server from reading any HTTP cookies from your system
4382 <term>Effect:</term>
4385 Deletes any <quote>Cookie:</quote> HTTP headers from client requests.
4392 <!-- Boolean, Parameterized, Multi-value -->
4394 <para>Boolean.</para>
4399 <term>Parameter:</term>
4411 This action is only concerned with <emphasis>outgoing</emphasis> HTTP cookies. For
4412 <emphasis>incoming</emphasis> HTTP cookies, use
4413 <literal><link linkend="crunch-incoming-cookies">crunch-incoming-cookies</link></literal>.
4414 Use <emphasis>both</emphasis> to disable HTTP cookies completely.
4417 It makes <emphasis>no sense at all</emphasis> to use this action in conjunction
4418 with the <literal><link linkend="session-cookies-only">session-cookies-only</link></literal> action,
4419 since it would prevent the session cookies from being read.
4425 <term>Example usage:</term>
4428 <screen>+crunch-outgoing-cookies</screen>
4437 <!-- ~~~~~ New section ~~~~~ -->
4438 <sect3 renderas="sect4" id="deanimate-gifs">
4439 <title>deanimate-gifs</title>
4443 <term>Typical use:</term>
4445 <para>Stop those annoying, distracting animated GIF images.</para>
4450 <term>Effect:</term>
4453 De-animate GIF animations, i.e. reduce them to their first or last image.
4460 <!-- boolean, parameterized, Multi-value -->
4462 <para>Parameterized.</para>
4467 <term>Parameter:</term>
4470 <quote>last</quote> or <quote>first</quote>
4479 This will also shrink the images considerably (in bytes, not pixels!). If
4480 the option <quote>first</quote> is given, the first frame of the animation
4481 is used as the replacement. If <quote>last</quote> is given, the last
4482 frame of the animation is used instead, which probably makes more sense for
4483 most banner animations, but also has the risk of not showing the entire
4484 last frame (if it is only a delta to an earlier frame).
4487 You can safely use this action with patterns that will also match non-GIF
4488 objects, because no attempt will be made at anything that doesn't look like
4495 <term>Example usage:</term>
4498 <screen>+deanimate-gifs{last}</screen>
4505 <!-- ~~~~~ New section ~~~~~ -->
4506 <sect3 renderas="sect4" id="downgrade-http-version">
4507 <title>downgrade-http-version</title>
4511 <term>Typical use:</term>
4513 <para>Work around (very rare) problems with HTTP/1.1</para>
4518 <term>Effect:</term>
4521 Downgrades HTTP/1.1 client requests and server replies to HTTP/1.0.
4528 <!-- boolean, parameterized, Multi-value -->
4530 <para>Boolean.</para>
4535 <term>Parameter:</term>
4547 This is a left-over from the time when <application>Privoxy</application>
4548 didn't support important HTTP/1.1 features well. It is left here for the
4549 unlikely case that you experience HTTP/1.1-related problems with some server
4553 Note that enabling this action is only a workaround. It should not
4554 be enabled for sites that work without it. While it shouldn't break
4555 any pages, it has an (usually negative) performance impact.
4558 If you come across a site where enabling this action helps, please report it,
4559 so the cause of the problem can be analyzed. If the problem turns out to be
4560 caused by a bug in <application>Privoxy</application> it should be
4561 fixed so the following release works without the work around.
4567 <term>Example usage (section):</term>
4570 <screen>{+downgrade-http-version}
4571 problem-host.example.com</screen>
4579 <!-- ~~~~~ New section ~~~~~ -->
4580 <sect3 renderas="sect4" id="fast-redirects">
4581 <title>fast-redirects</title>
4585 <term>Typical use:</term>
4587 <para>Fool some click-tracking scripts and speed up indirect links.</para>
4592 <term>Effect:</term>
4595 Detects redirection URLs and redirects the browser without contacting
4596 the redirection server first.
4603 <!-- boolean, parameterized, Multi-value -->
4605 <para>Parameterized.</para>
4610 <term>Parameter:</term>
4615 <quote>simple-check</quote> to just search for the string <quote>http://</quote>
4616 to detect redirection URLs.
4621 <quote>check-decoded-url</quote> to decode URLs (if necessary) before searching
4622 for redirection URLs.
4633 Many sites, like yahoo.com, don't just link to other sites. Instead, they
4634 will link to some script on their own servers, giving the destination as a
4635 parameter, which will then redirect you to the final target. URLs
4636 resulting from this scheme typically look like:
4637 <quote>http://www.example.org/click-tracker.cgi?target=http%3a//www.example.net/</quote>.
4640 Sometimes, there are even multiple consecutive redirects encoded in the
4641 URL. These redirections via scripts make your web browsing more traceable,
4642 since the server from which you follow such a link can see where you go
4643 to. Apart from that, valuable bandwidth and time is wasted, while your
4644 browser asks the server for one redirect after the other. Plus, it feeds
4648 This feature is currently not very smart and is scheduled for improvement.
4649 If it is enabled by default, you will have to create some exceptions to
4650 this action. It can lead to failures in several ways:
4653 Not every URLs with other URLs as parameters is evil.
4654 Some sites offer a real service that requires this information to work.
4655 For example a validation service needs to know, which document to validate.
4656 <literal>fast-redirects</literal> assumes that every URL parameter that
4657 looks like another URL is a redirection target, and will always redirect to
4658 the last one. Most of the time the assumption is correct, but if it isn't,
4659 the user gets redirected anyway.
4662 Another failure occurs if the URL contains other parameters after the URL parameter.
4664 <quote>http://www.example.org/?redirect=http%3a//www.example.net/&foo=bar</quote>.
4665 contains the redirection URL <quote>http://www.example.net/</quote>,
4666 followed by another parameter. <literal>fast-redirects</literal> doesn't know that
4667 and will cause a redirect to <quote>http://www.example.net/&foo=bar</quote>.
4668 Depending on the target server configuration, the parameter will be silently ignored
4669 or lead to a <quote>page not found</quote> error. You can prevent this problem by
4670 first using the <literal><link linkend="redirect">redirect</link></literal> action
4671 to remove the last part of the URL, but it requires a little effort.
4674 To detect a redirection URL, <literal>fast-redirects</literal> only
4675 looks for the string <quote>http://</quote>, either in plain text
4676 (invalid but often used) or encoded as <quote>http%3a//</quote>.
4677 Some sites use their own URL encoding scheme, encrypt the address
4678 of the target server or replace it with a database id. In theses cases
4679 <literal>fast-redirects</literal> is fooled and the request reaches the
4680 redirection server where it probably gets logged.
4686 <term>Example usage:</term>
4690 { +fast-redirects{simple-check} }
4693 { +fast-redirects{check-decoded-url} }
4694 another.example.com/testing</screen>
4703 <!-- ~~~~~ New section ~~~~~ -->
4704 <sect3 renderas="sect4" id="filter">
4705 <title>filter</title>
4709 <term>Typical use:</term>
4711 <para>Get rid of HTML and JavaScript annoyances, banner advertisements (by size),
4712 do fun text replacements, add personalized effects, etc.</para>
4717 <term>Effect:</term>
4720 All instances of text-based type, most notably HTML and JavaScript, to which
4721 this action applies, can be filtered on-the-fly through the specified regular
4722 expression based substitutions. (Note: as of version 3.0.3 plain text documents
4723 are exempted from filtering, because web servers often use the
4724 <literal>text/plain</literal> MIME type for all files whose type they don't know.)
4731 <!-- boolean, parameterized, Multi-value -->
4733 <para>Parameterized.</para>
4738 <term>Parameter:</term>
4741 The name of a content filter, as defined in the <link linkend="filter-file">filter file</link>.
4742 Filters can be defined in one or more files as defined by the
4743 <literal><link linkend="filterfile">filterfile</link></literal>
4744 option in the <link linkend="config">config file</link>.
4745 <filename>default.filter</filename> is the collection of filters
4746 supplied by the developers. Locally defined filters should go
4747 in their own file, such as <filename>user.filter</filename>.
4750 When used in its negative form,
4751 and without parameters, <emphasis>all</emphasis> filtering is completely disabled.
4760 For your convenience, there are a number of pre-defined filters available
4761 in the distribution filter file that you can use. See the examples below for
4765 Filtering requires buffering the page content, which may appear to
4766 slow down page rendering since nothing is displayed until all content has
4767 passed the filters. (The total time until the page is completely rendered
4768 doesn't change much, but it may be perceived as slower since the page is
4769 not incrementally displayed.)
4770 This effect will be more noticeable on slower connections.
4773 <quote>Rolling your own</quote>
4774 filters requires a knowledge of
4775 <ulink url="http://en.wikipedia.org/wiki/Regular_expressions"><quote>Regular
4776 Expressions</quote></ulink> and
4777 <ulink url="http://en.wikipedia.org/wiki/Html"><quote>HTML</quote></ulink>.
4778 This is very powerful feature, and potentially very intrusive.
4779 Filters should be used with caution, and where an equivalent
4780 <quote>action</quote> is not available.
4783 The amount of data that can be filtered is limited to the
4784 <literal><link linkend="buffer-limit">buffer-limit</link></literal>
4785 option in the main <link linkend="config">config file</link>. The
4786 default is 4096 KB (4 Megs). Once this limit is exceeded, the buffered
4787 data, and all pending data, is passed through unfiltered.
4790 Inappropriate MIME types, such as zipped files, are not filtered at all.
4791 (Again, only text-based types except plain text). Encrypted SSL data
4792 (from HTTPS servers) cannot be filtered either, since this would violate
4793 the integrity of the secure transaction. In some situations it might
4794 be necessary to protect certain text, like source code, from filtering
4795 by defining appropriate <literal>-filter</literal> exceptions.
4798 Compressed content can't be filtered either, but if &my-app;
4799 is compiled with zlib support and a supported compression algorithm
4800 is used (gzip or deflate), &my-app; can first decompress the content
4804 If you use a &my-app; version without zlib support, but want filtering to work on
4805 as much documents as possible, even those that would normally be sent compressed,
4806 you must use the <literal><link linkend="prevent-compression">prevent-compression</link></literal>
4807 action in conjunction with <literal>filter</literal>.
4810 Content filtering can achieve some of the same effects as the
4811 <literal><link linkend="block">block</link></literal>
4812 action, i.e. it can be used to block ads and banners. But the mechanism
4813 works quite differently. One effective use, is to block ad banners
4814 based on their size (see below), since many of these seem to be somewhat
4818 <link linkend="contact">Feedback</link> with suggestions for new or
4819 improved filters is particularly welcome!
4822 The below list has only the names and a one-line description of each
4823 predefined filter. There are <link linkend="predefined-filters">more
4824 verbose explanations</link> of what these filters do in the <link
4825 linkend="filter-file">filter file chapter</link>.
4831 <term>Example usage (with filters from the distribution <filename>default.filter</filename> file).
4832 See <link linkend="PREDEFINED-FILTERS">the Predefined Filters section</link> for
4833 more explanation on each:</term>
4836 <anchor id="filter-js-annoyances">
4837 <screen>+filter{js-annoyances} # Get rid of particularly annoying JavaScript abuse.</screen>
4840 <anchor id="filter-js-events">
4841 <screen>+filter{js-events} # Kill all JS event bindings and timers (Radically destructive! Only for extra nasty sites).</screen>
4844 <anchor id="filter-html-annoyances">
4845 <screen>+filter{html-annoyances} # Get rid of particularly annoying HTML abuse.</screen>
4848 <anchor id="filter-content-cookies">
4849 <screen>+filter{content-cookies} # Kill cookies that come in the HTML or JS content.</screen>
4852 <anchor id="filter-refresh-tags">
4853 <screen>+filter{refresh-tags} # Kill automatic refresh tags (for dial-on-demand setups).</screen>
4856 <anchor id="filter-unsolicited-popups">
4857 <screen>+filter{unsolicited-popups} # Disable only unsolicited pop-up windows. Useful if your browser lacks this ability.</screen>
4860 <anchor id="filter-all-popups">
4861 <screen>+filter{all-popups} # Kill all popups in JavaScript and HTML. Useful if your browser lacks this ability.</screen>
4864 <anchor id="filter-img-reorder">
4865 <screen>+filter{img-reorder} # Reorder attributes in <img> tags to make the banners-by-* filters more effective.</screen>
4868 <anchor id="filter-banners-by-size">
4869 <screen>+filter{banners-by-size} # Kill banners by size.</screen>
4872 <anchor id="filter-banners-by-link">
4873 <screen>+filter{banners-by-link} # Kill banners by their links to known clicktrackers.</screen>
4876 <anchor id="filter-webbugs">
4877 <screen>+filter{webbugs} # Squish WebBugs (1x1 invisible GIFs used for user tracking).</screen>
4880 <anchor id="filter-tiny-textforms">
4881 <screen>+filter{tiny-textforms} # Extend those tiny textareas up to 40x80 and kill the hard wrap.</screen>
4884 <anchor id="filter-jumping-windows">
4885 <screen>+filter{jumping-windows} # Prevent windows from resizing and moving themselves.</screen>
4888 <anchor id="filter-frameset-borders">
4889 <screen>+filter{frameset-borders} # Give frames a border and make them resizable.</screen>
4892 <anchor id="filter-demoronizer">
4893 <screen>+filter{demoronizer} # Fix MS's non-standard use of standard charsets.</screen>
4896 <anchor id="filter-shockwave-flash">
4897 <screen>+filter{shockwave-flash} # Kill embedded Shockwave Flash objects.</screen>
4900 <anchor id="filter-quicktime-kioskmode">
4901 <screen>+filter{quicktime-kioskmode} # Make Quicktime movies saveable.</screen>
4904 <anchor id="filter-fun">
4905 <screen>+filter{fun} # Text replacements for subversive browsing fun!</screen>
4908 <anchor id="filter-crude-parental">
4909 <screen>+filter{crude-parental} # Crude parental filtering. Note that this filter doesn't work reliably.</screen>
4912 <anchor id="filter-ie-exploits">
4913 <screen>+filter{ie-exploits} # Disable some known Internet Explorer bug exploits.</screen>
4916 <anchor id="filter-site-specifics">
4917 <screen>+filter{site-specifics} # Cure for site-specific problems. Don't apply generally!</screen>
4920 <anchor id="filter-no-ping">
4921 <screen>+filter{no-ping} # Removes non-standard ping attributes in <a> and <area> tags.</screen>
4924 <anchor id="filter-google">
4925 <screen>+filter{google} # CSS-based block for Google text ads. Also removes a width limitation and the toolbar advertisement.</screen>
4928 <anchor id="filter-yahoo">
4929 <screen>+filter{yahoo} # CSS-based block for Yahoo text ads. Also removes a width limitation.</screen>
4932 <anchor id="filter-msn">
4933 <screen>+filter{msn} # CSS-based block for MSN text ads. Also removes tracking URLs and a width limitation.</screen>
4936 <anchor id="filter-blogspot">
4937 <screen>+filter{blogspot} # Cleans up some Blogspot blogs. Read the fine print before using this.</screen>
4945 <!-- ~~~~~ New section ~~~~~ -->
4946 <sect3 renderas="sect4" id="force-text-mode">
4947 <title>force-text-mode</title>
4953 <term>Typical use:</term>
4955 <para>Force <application>Privoxy</application> to treat a document as if it was in some kind of <emphasis>text</emphasis> format. </para>
4960 <term>Effect:</term>
4963 Declares a document as text, even if the <quote>Content-Type:</quote> isn't detected as such.
4970 <!-- Boolean, Parameterized, Multi-value -->
4972 <para>Boolean.</para>
4977 <term>Parameter:</term>
4989 As explained <literal><link linkend="filter">above</link></literal>,
4990 <application>Privoxy</application> tries to only filter files that are
4991 in some kind of text format. The same restrictions apply to
4992 <literal><link linkend="content-type-overwrite">content-type-overwrite</link></literal>.
4993 <literal>force-text-mode</literal> declares a document as text,
4994 without looking at the <quote>Content-Type:</quote> first.
4998 Think twice before activating this action. Filtering binary data
4999 with regular expressions can cause file damage.
5006 <term>Example usage:</term>
5019 <!-- ~~~~~ New section ~~~~~ -->
5020 <sect3 renderas="sect4" id="forward-override">
5021 <title>forward-override</title>
5027 <term>Typical use:</term>
5029 <para>Change the forwarding settings based on User-Agent or request origin</para>
5034 <term>Effect:</term>
5037 Overrules the forward directives in the configuration file.
5044 <!-- Boolean, Parameterized, Multi-value -->
5046 <para>Multi-value.</para>
5051 <term>Parameter:</term>
5055 <para><quote>forward .</quote> to use a direct connection without any additional proxies.</para>
5059 <quote>forward 127.0.0.1:8123</quote> to use the HTTP proxy listening at 127.0.0.1 port 8123.
5064 <quote>forward-socks4a 127.0.0.1:9050 .</quote> to use the socks4a proxy listening at
5065 127.0.0.1 port 9050. Replace <quote>forward-socks4a</quote> with <quote>forward-socks4</quote>
5066 to use a socks4 connection (with local DNS resolution) instead, use <quote>forward-socks5</quote>
5067 for socks5 connections (with remote DNS resolution).
5072 <quote>forward-socks4a 127.0.0.1:9050 proxy.example.org:8000</quote> to use the socks4a proxy
5073 listening at 127.0.0.1 port 9050 to reach the HTTP proxy listening at proxy.example.org port 8000.
5074 Replace <quote>forward-socks4a</quote> with <quote>forward-socks4</quote> to use a socks4 connection
5075 (with local DNS resolution) instead, use <quote>forward-socks5</quote>
5076 for socks5 connections (with remote DNS resolution).
5087 This action takes parameters similar to the
5088 <link linkend="forwarding">forward</link> directives in the configuration
5089 file, but without the URL pattern. It can be used as replacement, but normally it's only
5090 used in cases where matching based on the request URL isn't sufficient.
5094 Please read the description for the <link linkend="forwarding">forward</link> directives before
5095 using this action. Forwarding to the wrong people will reduce your privacy and increase the
5096 chances of man-in-the-middle attacks.
5099 If the ports are missing or invalid, default values will be used. This might change
5100 in the future and you shouldn't rely on it. Otherwise incorrect syntax causes Privoxy
5104 Use the <ulink url="http://config.privoxy.org/show-url-info">show-url-info CGI page</ulink>
5105 to verify that your forward settings do what you thought the do.
5112 <term>Example usage:</term>
5116 # Always use direct connections for requests previously tagged as
5117 # <quote>User-Agent: fetch libfetch/2.0</quote> and make sure
5118 # resuming downloads continues to work.
5119 # This way you can continue to use Tor for your normal browsing,
5120 # without overloading the Tor network with your FreeBSD ports updates
5121 # or downloads of bigger files like ISOs.
5122 # Note that HTTP headers are easy to fake and therefore their
5123 # values are as (un)trustworthy as your clients and users.
5124 {+forward-override{forward .} \
5125 -hide-if-modified-since \
5126 -overwrite-last-modified \
5128 TAG:^User-Agent: fetch libfetch/2\.0$
5137 <!-- ~~~~~ New section ~~~~~ -->
5138 <sect3 renderas="sect4" id="handle-as-empty-document">
5139 <title>handle-as-empty-document</title>
5145 <term>Typical use:</term>
5147 <para>Mark URLs that should be replaced by empty documents <emphasis>if they get blocked</emphasis></para>
5152 <term>Effect:</term>
5155 This action alone doesn't do anything noticeable. It just marks URLs.
5156 If the <literal><link linkend="block">block</link></literal> action <emphasis>also applies</emphasis>,
5157 the presence or absence of this mark decides whether an HTML <quote>BLOCKED</quote>
5158 page, or an empty document will be sent to the client as a substitute for the blocked content.
5159 The <emphasis>empty</emphasis> document isn't literally empty, but actually contains a single space.
5166 <!-- Boolean, Parameterized, Multi-value -->
5168 <para>Boolean.</para>
5173 <term>Parameter:</term>
5185 Some browsers complain about syntax errors if JavaScript documents
5186 are blocked with <application>Privoxy's</application>
5187 default HTML page; this option can be used to silence them.
5188 And of course this action can also be used to eliminate the &my-app;
5189 BLOCKED message in frames.
5192 The content type for the empty document can be specified with
5193 <literal><link linkend="content-type-overwrite">content-type-overwrite{}</link></literal>,
5194 but usually this isn't necessary.
5200 <term>Example usage:</term>
5203 <screen># Block all documents on example.org that end with ".js",
5204 # but send an empty document instead of the usual HTML message.
5205 {+block{Blocked JavaScript} +handle-as-empty-document}
5215 <!-- ~~~~~ New section ~~~~~ -->
5216 <sect3 renderas="sect4" id="handle-as-image">
5217 <title>handle-as-image</title>
5221 <term>Typical use:</term>
5223 <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>
5228 <term>Effect:</term>
5231 This action alone doesn't do anything noticeable. It just marks URLs as images.
5232 If the <literal><link linkend="block">block</link></literal> action <emphasis>also applies</emphasis>,
5233 the presence or absence of this mark decides whether an HTML <quote>blocked</quote>
5234 page, or a replacement image (as determined by the <literal><link
5235 linkend="set-image-blocker">set-image-blocker</link></literal> action) will be sent to the
5236 client as a substitute for the blocked content.
5243 <!-- Boolean, Parameterized, Multi-value -->
5245 <para>Boolean.</para>
5250 <term>Parameter:</term>
5262 The below generic example section is actually part of <filename>default.action</filename>.
5263 It marks all URLs with well-known image file name extensions as images and should
5267 Users will probably only want to use the handle-as-image action in conjunction with
5268 <literal><link linkend="block">block</link></literal>, to block sources of banners, whose URLs don't
5269 reflect the file type, like in the second example section.
5272 Note that you cannot treat HTML pages as images in most cases. For instance, (in-line) ad
5273 frames require an HTML page to be sent, or they won't display properly.
5274 Forcing <literal>handle-as-image</literal> in this situation will not replace the
5275 ad frame with an image, but lead to error messages.
5281 <term>Example usage (sections):</term>
5284 <screen># Generic image extensions:
5287 /.*\.(gif|jpg|jpeg|png|bmp|ico)$
5289 # These don't look like images, but they're banners and should be
5290 # blocked as images:
5292 {+block{Nasty banners.} +handle-as-image}
5293 nasty-banner-server.example.com/junk.cgi\?output=trash
5302 <!-- ~~~~~ New section ~~~~~ -->
5303 <sect3 renderas="sect4" id="hide-accept-language">
5304 <title>hide-accept-language</title>
5310 <term>Typical use:</term>
5312 <para>Pretend to use different language settings.</para>
5317 <term>Effect:</term>
5320 Deletes or replaces the <quote>Accept-Language:</quote> HTTP header in client requests.
5327 <!-- Boolean, Parameterized, Multi-value -->
5329 <para>Parameterized.</para>
5334 <term>Parameter:</term>
5337 Keyword: <quote>block</quote>, or any user defined value.
5346 Faking the browser's language settings can be useful to make a
5347 foreign User-Agent set with
5348 <literal><link linkend="hide-user-agent">hide-user-agent</link></literal>
5352 However some sites with content in different languages check the
5353 <quote>Accept-Language:</quote> to decide which one to take by default.
5354 Sometimes it isn't possible to later switch to another language without
5355 changing the <quote>Accept-Language:</quote> header first.
5358 Therefore it's a good idea to either only change the
5359 <quote>Accept-Language:</quote> header to languages you understand,
5360 or to languages that aren't wide spread.
5363 Before setting the <quote>Accept-Language:</quote> header
5364 to a rare language, you should consider that it helps to
5365 make your requests unique and thus easier to trace.
5366 If you don't plan to change this header frequently,
5367 you should stick to a common language.
5373 <term>Example usage (section):</term>
5376 <screen># Pretend to use Canadian language settings.
5377 {+hide-accept-language{en-ca} \
5378 +hide-user-agent{Mozilla/5.0 (X11; U; OpenBSD i386; en-CA; rv:1.8.0.4) Gecko/20060628 Firefox/1.5.0.4} \
5388 <!-- ~~~~~ New section ~~~~~ -->
5389 <sect3 renderas="sect4" id="hide-content-disposition">
5390 <title>hide-content-disposition</title>
5396 <term>Typical use:</term>
5398 <para>Prevent download menus for content you prefer to view inside the browser.</para>
5403 <term>Effect:</term>
5406 Deletes or replaces the <quote>Content-Disposition:</quote> HTTP header set by some servers.
5413 <!-- Boolean, Parameterized, Multi-value -->
5415 <para>Parameterized.</para>
5420 <term>Parameter:</term>
5423 Keyword: <quote>block</quote>, or any user defined value.
5432 Some servers set the <quote>Content-Disposition:</quote> HTTP header for
5433 documents they assume you want to save locally before viewing them.
5434 The <quote>Content-Disposition:</quote> header contains the file name
5435 the browser is supposed to use by default.
5438 In most browsers that understand this header, it makes it impossible to
5439 <emphasis>just view</emphasis> the document, without downloading it first,
5440 even if it's just a simple text file or an image.
5443 Removing the <quote>Content-Disposition:</quote> header helps
5444 to prevent this annoyance, but some browsers additionally check the
5445 <quote>Content-Type:</quote> header, before they decide if they can
5446 display a document without saving it first. In these cases, you have
5447 to change this header as well, before the browser stops displaying
5451 It is also possible to change the server's file name suggestion
5452 to another one, but in most cases it isn't worth the time to set
5456 This action will probably be removed in the future,
5457 use server-header filters instead.
5463 <term>Example usage:</term>
5466 <screen># Disarm the download link in Sourceforge's patch tracker
5468 +content-type-overwrite{text/plain}\
5469 +hide-content-disposition{block} }
5470 .sourceforge.net/tracker/download\.php</screen>
5478 <!-- ~~~~~ New section ~~~~~ -->
5479 <sect3 renderas="sect4" id="hide-if-modified-since">
5480 <title>hide-if-modified-since</title>
5486 <term>Typical use:</term>
5488 <para>Prevent yet another way to track the user's steps between sessions.</para>
5493 <term>Effect:</term>
5496 Deletes the <quote>If-Modified-Since:</quote> HTTP client header or modifies its value.
5503 <!-- Boolean, Parameterized, Multi-value -->
5505 <para>Parameterized.</para>
5510 <term>Parameter:</term>
5513 Keyword: <quote>block</quote>, or a user defined value that specifies a range of hours.
5522 Removing this header is useful for filter testing, where you want to force a real
5523 reload instead of getting status code <quote>304</quote>, which would cause the
5524 browser to use a cached copy of the page.
5527 Instead of removing the header, <literal>hide-if-modified-since</literal> can
5528 also add or subtract a random amount of time to/from the header's value.
5529 You specify a range of minutes where the random factor should be chosen from and
5530 <application>Privoxy</application> does the rest. A negative value means
5531 subtracting, a positive value adding.
5534 Randomizing the value of the <quote>If-Modified-Since:</quote> makes
5535 it less likely that the server can use the time as a cookie replacement,
5536 but you will run into caching problems if the random range is too high.
5539 It is a good idea to only use a small negative value and let
5540 <literal><link linkend="overwrite-last-modified">overwrite-last-modified</link></literal>
5541 handle the greater changes.
5544 It is also recommended to use this action together with
5545 <literal><link linkend="crunch-if-none-match">crunch-if-none-match</link></literal>,
5546 otherwise it's more or less pointless.
5552 <term>Example usage (section):</term>
5555 <screen># Let the browser revalidate but make tracking based on the time less likely.
5556 {+hide-if-modified-since{-60} \
5557 +overwrite-last-modified{randomize} \
5558 +crunch-if-none-match}
5567 <!-- ~~~~~ New section ~~~~~ -->
5568 <sect3 renderas="sect4" id="hide-from-header">
5569 <title>hide-from-header</title>
5573 <term>Typical use:</term>
5575 <para>Keep your (old and ill) browser from telling web servers your email address</para>
5580 <term>Effect:</term>
5583 Deletes any existing <quote>From:</quote> HTTP header, or replaces it with the
5591 <!-- Boolean, Parameterized, Multi-value -->
5593 <para>Parameterized.</para>
5598 <term>Parameter:</term>
5601 Keyword: <quote>block</quote>, or any user defined value.
5610 The keyword <quote>block</quote> will completely remove the header
5611 (not to be confused with the <literal><link linkend="block">block</link></literal>
5615 Alternately, you can specify any value you prefer to be sent to the web
5616 server. If you do, it is a matter of fairness not to use any address that
5617 is actually used by a real person.
5620 This action is rarely needed, as modern web browsers don't send
5621 <quote>From:</quote> headers anymore.
5627 <term>Example usage:</term>
5630 <screen>+hide-from-header{block}</screen> or
5631 <screen>+hide-from-header{spam-me-senseless@sittingduck.example.com}</screen>
5639 <!-- ~~~~~ New section ~~~~~ -->
5640 <sect3 renderas="sect4" id="hide-referrer">
5641 <title>hide-referrer</title>
5642 <anchor id="hide-referer">
5645 <term>Typical use:</term>
5647 <para>Conceal which link you followed to get to a particular site</para>
5652 <term>Effect:</term>
5655 Deletes the <quote>Referer:</quote> (sic) HTTP header from the client request,
5656 or replaces it with a forged one.
5663 <!-- Boolean, Parameterized, Multi-value -->
5665 <para>Parameterized.</para>
5670 <term>Parameter:</term>
5674 <para><quote>conditional-block</quote> to delete the header completely if the host has changed.</para>
5677 <para><quote>conditional-forge</quote> to forge the header if the host has changed.</para>
5680 <para><quote>block</quote> to delete the header unconditionally.</para>
5683 <para><quote>forge</quote> to pretend to be coming from the homepage of the server we are talking to.</para>
5686 <para>Any other string to set a user defined referrer.</para>
5696 <literal>conditional-block</literal> is the only parameter,
5697 that isn't easily detected in the server's log file. If it blocks the
5698 referrer, the request will look like the visitor used a bookmark or
5699 typed in the address directly.
5702 Leaving the referrer unmodified for requests on the same host
5703 allows the server owner to see the visitor's <quote>click path</quote>,
5704 but in most cases she could also get that information by comparing
5705 other parts of the log file: for example the User-Agent if it isn't
5706 a very common one, or the user's IP address if it doesn't change between
5710 Always blocking the referrer, or using a custom one, can lead to
5711 failures on servers that check the referrer before they answer any
5712 requests, in an attempt to prevent their content from being
5713 embedded or linked to elsewhere.
5716 Both <literal>conditional-block</literal> and <literal>forge</literal>
5717 will work with referrer checks, as long as content and valid referring page
5718 are on the same host. Most of the time that's the case.
5721 <literal>hide-referer</literal> is an alternate spelling of
5722 <literal>hide-referrer</literal> and the two can be can be freely
5723 substituted with each other. (<quote>referrer</quote> is the
5724 correct English spelling, however the HTTP specification has a bug - it
5725 requires it to be spelled as <quote>referer</quote>.)
5731 <term>Example usage:</term>
5734 <screen>+hide-referrer{forge}</screen> or
5735 <screen>+hide-referrer{http://www.yahoo.com/}</screen>
5743 <!-- ~~~~~ New section ~~~~~ -->
5744 <sect3 renderas="sect4" id="hide-user-agent">
5745 <title>hide-user-agent</title>
5749 <term>Typical use:</term>
5751 <para>Try to conceal your type of browser and client operating system</para>
5756 <term>Effect:</term>
5759 Replaces the value of the <quote>User-Agent:</quote> HTTP header
5760 in client requests with the specified value.
5767 <!-- Boolean, Parameterized, Multi-value -->
5769 <para>Parameterized.</para>
5774 <term>Parameter:</term>
5777 Any user-defined string.
5787 This can lead to problems on web sites that depend on looking at this header in
5788 order to customize their content for different browsers (which, by the
5789 way, is <emphasis>NOT</emphasis> the right thing to do: good web sites
5790 work browser-independently).
5794 Using this action in multi-user setups or wherever different types of
5795 browsers will access the same <application>Privoxy</application> is
5796 <emphasis>not recommended</emphasis>. In single-user, single-browser
5797 setups, you might use it to delete your OS version information from
5798 the headers, because it is an invitation to exploit known bugs for your
5799 OS. It is also occasionally useful to forge this in order to access
5800 sites that won't let you in otherwise (though there may be a good
5801 reason in some cases).
5804 More information on known user-agent strings can be found at
5805 <ulink url="http://www.user-agents.org/">http://www.user-agents.org/</ulink>
5807 <ulink url="http://en.wikipedia.org/wiki/User_agent">http://en.wikipedia.org/wiki/User_agent</ulink>.
5813 <term>Example usage:</term>
5816 <screen>+hide-user-agent{Netscape 6.1 (X11; I; Linux 2.4.18 i686)}</screen>
5824 <!-- ~~~~~ New section ~~~~~ -->
5825 <sect3 renderas="sect4" id="limit-connect">
5826 <title>limit-connect</title>
5830 <term>Typical use:</term>
5832 <para>Prevent abuse of <application>Privoxy</application> as a TCP proxy relay or disable SSL for untrusted sites</para>
5837 <term>Effect:</term>
5840 Specifies to which ports HTTP CONNECT requests are allowable.
5847 <!-- Boolean, Parameterized, Multi-value -->
5849 <para>Parameterized.</para>
5854 <term>Parameter:</term>
5857 A comma-separated list of ports or port ranges (the latter using dashes, with the minimum
5858 defaulting to 0 and the maximum to 65K).
5867 By default, i.e. if no <literal>limit-connect</literal> action applies,
5868 <application>Privoxy</application> allows HTTP CONNECT requests to all
5869 ports. Use <literal>limit-connect</literal> if fine-grained control
5870 is desired for some or all destinations.
5873 The CONNECT methods exists in HTTP to allow access to secure websites
5874 (<quote>https://</quote> URLs) through proxies. It works very simply:
5875 the proxy connects to the server on the specified port, and then
5876 short-circuits its connections to the client and to the remote server.
5877 This means CONNECT-enabled proxies can be used as TCP relays very easily.
5880 <application>Privoxy</application> relays HTTPS traffic without seeing
5881 the decoded content. Websites can leverage this limitation to circumvent &my-app;'s
5882 filters. By specifying an invalid port range you can disable HTTPS entirely.
5888 <term>Example usages:</term>
5890 <!-- I had trouble getting the spacing to look right in my browser -->
5891 <!-- I probably have the wrong font setup, bollocks. -->
5892 <!-- Apparently the emphasis tag uses a proportional font no matter what -->
5894 <screen>+limit-connect{443} # Port 443 is OK.
5895 +limit-connect{80,443} # Ports 80 and 443 are OK.
5896 +limit-connect{-3, 7, 20-100, 500-} # Ports less than 3, 7, 20 to 100 and above 500 are OK.
5897 +limit-connect{-} # All ports are OK
5898 +limit-connect{,} # No HTTPS/SSL traffic is allowed</screen>
5906 <!-- ~~~~~ New section ~~~~~ -->
5907 <sect3 renderas="sect4" id="limit-cookie-lifetime">
5908 <title>limit-cookie-lifetime</title>
5912 <term>Typical use:</term>
5914 <para>Limit the lifetime of HTTP cookies to a couple of minutes or hours.</para>
5919 <term>Effect:</term>
5922 Overwrites the expires field in Set-Cookie server headers if it's above the specified limit.
5929 <!-- Boolean, Parameterized, Multi-value -->
5931 <para>Parameterized.</para>
5936 <term>Parameter:</term>
5939 The lifetime limit in minutes, or 0.
5948 This action reduces the lifetime of HTTP cookies coming from the
5949 server to the specified number of minutes, starting from the time
5950 the cookie passes Privoxy.
5953 Cookies with a lifetime below the limit are not modified.
5954 The lifetime of session cookies is set to the specified limit.
5957 The effect of this action depends on the server.
5960 In case of servers which refresh their cookies with each response
5961 (or at least frequently), the lifetime limit set by this action
5963 Thus, a session associated with the cookie continues to work with
5964 this action enabled, as long as a new request is made before the
5965 last limit set is reached.
5968 However, some servers send their cookies once, with a lifetime of several
5969 years (the year 2037 is a popular choice), and do not refresh them
5970 until a certain event in the future, for example the user logging out.
5971 In this case this action may limit the absolute lifetime of the session,
5972 even if requests are made frequently.
5975 If the parameter is <quote>0</quote>, this action behaves like
5976 <literal><link linkend="session-cookies-only">session-cookies-only</link></literal>.
5982 <term>Example usages:</term>
5985 <screen>+limit-cookie-lifetime{60}
5993 <!-- ~~~~~ New section ~~~~~ -->
5994 <sect3 renderas="sect4" id="prevent-compression">
5995 <title>prevent-compression</title>
5999 <term>Typical use:</term>
6002 Ensure that servers send the content uncompressed, so it can be
6003 passed through <literal><link linkend="filter">filter</link></literal>s.
6009 <term>Effect:</term>
6012 Removes the Accept-Encoding header which can be used to ask for compressed transfer.
6019 <!-- Boolean, Parameterized, Multi-value -->
6021 <para>Boolean.</para>
6026 <term>Parameter:</term>
6038 More and more websites send their content compressed by default, which
6039 is generally a good idea and saves bandwidth. But the <literal><link
6040 linkend="filter">filter</link></literal> and
6041 <literal><link linkend="deanimate-gifs">deanimate-gifs</link></literal>
6042 actions need access to the uncompressed data.
6045 When compiled with zlib support (available since &my-app; 3.0.7), content that should be
6046 filtered is decompressed on-the-fly and you don't have to worry about this action.
6047 If you are using an older &my-app; version, or one that hasn't been compiled with zlib
6048 support, this action can be used to convince the server to send the content uncompressed.
6051 Most text-based instances compress very well, the size is seldom decreased by less than 50%,
6052 for markup-heavy instances like news feeds saving more than 90% of the original size isn't
6056 Not using compression will therefore slow down the transfer, and you should only
6057 enable this action if you really need it. As of &my-app; 3.0.7 it's disabled in all
6058 predefined action settings.
6061 Note that some (rare) ill-configured sites don't handle requests for uncompressed
6062 documents correctly. Broken PHP applications tend to send an empty document body,
6063 some IIS versions only send the beginning of the content. If you enable
6064 <literal>prevent-compression</literal> per default, you might want to add
6065 exceptions for those sites. See the example for how to do that.
6071 <term>Example usage (sections):</term>
6075 # Selectively turn off compression, and enable a filter
6077 { +filter{tiny-textforms} +prevent-compression }
6078 # Match only these sites
6083 # Or instead, we could set a universal default:
6085 { +prevent-compression }
6088 # Then maybe make exceptions for broken sites:
6090 { -prevent-compression }
6091 .compusa.com/</screen>
6100 <!-- ~~~~~ New section ~~~~~ -->
6101 <sect3 renderas="sect4" id="overwrite-last-modified">
6102 <title>overwrite-last-modified</title>
6108 <term>Typical use:</term>
6110 <para>Prevent yet another way to track the user's steps between sessions.</para>
6115 <term>Effect:</term>
6118 Deletes the <quote>Last-Modified:</quote> HTTP server header or modifies its value.
6125 <!-- Boolean, Parameterized, Multi-value -->
6127 <para>Parameterized.</para>
6132 <term>Parameter:</term>
6135 One of the keywords: <quote>block</quote>, <quote>reset-to-request-time</quote>
6136 and <quote>randomize</quote>
6145 Removing the <quote>Last-Modified:</quote> header is useful for filter
6146 testing, where you want to force a real reload instead of getting status
6147 code <quote>304</quote>, which would cause the browser to reuse the old
6148 version of the page.
6151 The <quote>randomize</quote> option overwrites the value of the
6152 <quote>Last-Modified:</quote> header with a randomly chosen time
6153 between the original value and the current time. In theory the server
6154 could send each document with a different <quote>Last-Modified:</quote>
6155 header to track visits without using cookies. <quote>Randomize</quote>
6156 makes it impossible and the browser can still revalidate cached documents.
6159 <quote>reset-to-request-time</quote> overwrites the value of the
6160 <quote>Last-Modified:</quote> header with the current time. You could use
6161 this option together with
6162 <literal><link linkend="hide-if-modified-since">hide-if-modified-since</link></literal>
6163 to further customize your random range.
6166 The preferred parameter here is <quote>randomize</quote>. It is safe
6167 to use, as long as the time settings are more or less correct.
6168 If the server sets the <quote>Last-Modified:</quote> header to the time
6169 of the request, the random range becomes zero and the value stays the same.
6170 Therefore you should later randomize it a second time with
6171 <literal><link linkend="hide-if-modified-since">hided-if-modified-since</link></literal>,
6175 It is also recommended to use this action together with
6176 <literal><link linkend="crunch-if-none-match">crunch-if-none-match</link></literal>.
6182 <term>Example usage:</term>
6185 <screen># Let the browser revalidate without being tracked across sessions
6186 { +hide-if-modified-since{-60} \
6187 +overwrite-last-modified{randomize} \
6188 +crunch-if-none-match}
6197 <!-- ~~~~~ New section ~~~~~ -->
6198 <sect3 renderas="sect4" id="redirect">
6199 <title>redirect</title>
6205 <term>Typical use:</term>
6208 Redirect requests to other sites.
6214 <term>Effect:</term>
6217 Convinces the browser that the requested document has been moved
6218 to another location and the browser should get it from there.
6225 <!-- Boolean, Parameterized, Multi-value -->
6227 <para>Parameterized</para>
6232 <term>Parameter:</term>
6235 An absolute URL or a single pcrs command.
6244 Requests to which this action applies are answered with a
6245 HTTP redirect to URLs of your choosing. The new URL is
6246 either provided as parameter, or derived by applying a
6247 single pcrs command to the original URL.
6250 The syntax for pcrs commands is documented in the
6251 <link linkend="filter-file">filter file</link> section.
6254 This action will be ignored if you use it together with
6255 <literal><link linkend="block">block</link></literal>.
6256 It can be combined with
6257 <literal><link linkend="fast-redirects">fast-redirects{check-decoded-url}</link></literal>
6258 to redirect to a decoded version of a rewritten URL.
6261 Use this action carefully, make sure not to create redirection loops
6262 and be aware that using your own redirects might make it
6263 possible to fingerprint your requests.
6266 In case of problems with your redirects, or simply to watch
6267 them working, enable <link linkend="DEBUG">debug 128</link>.
6273 <term>Example usages:</term>
6276 <screen># Replace example.com's style sheet with another one
6277 { +redirect{http://localhost/css-replacements/example.com.css} }
6278 example.com/stylesheet\.css
6280 # Create a short, easy to remember nickname for a favorite site
6281 # (relies on the browser accept and forward invalid URLs to &my-app;)
6282 { +redirect{http://www.privoxy.org/user-manual/actions-file.html} }
6285 # Always use the expanded view for Undeadly.org articles
6286 # (Note the $ at the end of the URL pattern to make sure
6287 # the request for the rewritten URL isn't redirected as well)
6288 {+redirect{s@$@&mode=expanded@}}
6289 undeadly.org/cgi\?action=article&sid=\d*$
6291 # Redirect Google search requests to MSN
6292 {+redirect{s@^http://[^/]*/search\?q=([^&]*).*@http://search.msn.com/results.aspx?q=$1@}}
6295 # Redirect MSN search requests to Yahoo
6296 {+redirect{s@^http://[^/]*/results\.aspx\?q=([^&]*).*@http://search.yahoo.com/search?p=$1@}}
6297 search.msn.com//results\.aspx\?q=
6299 # Redirect remote requests for this manual
6300 # to the local version delivered by Privoxy
6301 {+redirect{s@^http://www@http://config@}}
6302 www.privoxy.org/user-manual/</screen>
6311 <!-- ~~~~~ New section ~~~~~ -->
6312 <sect3 renderas="sect4" id="server-header-filter">
6313 <title>server-header-filter</title>
6317 <term>Typical use:</term>
6320 Rewrite or remove single server headers.
6326 <term>Effect:</term>
6329 All server headers to which this action applies are filtered on-the-fly
6330 through the specified regular expression based substitutions.
6337 <!-- boolean, parameterized, Multi-value -->
6339 <para>Parameterized.</para>
6344 <term>Parameter:</term>
6347 The name of a server-header filter, as defined in one of the
6348 <link linkend="filter-file">filter files</link>.
6357 Server-header filters are applied to each header on its own, not to
6358 all at once. This makes it easier to diagnose problems, but on the downside
6359 you can't write filters that only change header x if header y's value is z.
6360 You can do that by using tags though.
6363 Server-header filters are executed after the other header actions have finished
6364 and use their output as input.
6367 Please refer to the <link linkend="filter-file">filter file chapter</link>
6368 to learn which server-header filters are available by default, and how to
6375 <term>Example usage (section):</term>
6379 {+server-header-filter{html-to-xml}}
6380 example.org/xml-instance-that-is-delivered-as-html
6382 {+server-header-filter{xml-to-html}}
6383 example.org/instance-that-is-delivered-as-xml-but-is-not
6393 <!-- ~~~~~ New section ~~~~~ -->
6394 <sect3 renderas="sect4" id="server-header-tagger">
6395 <title>server-header-tagger</title>
6399 <term>Typical use:</term>
6402 Enable or disable filters based on the Content-Type header.
6408 <term>Effect:</term>
6411 Server headers to which this action applies are filtered on-the-fly through
6412 the specified regular expression based substitutions, the result is used as
6420 <!-- boolean, parameterized, Multi-value -->
6422 <para>Parameterized.</para>
6427 <term>Parameter:</term>
6430 The name of a server-header tagger, as defined in one of the
6431 <link linkend="filter-file">filter files</link>.
6440 Server-header taggers are applied to each header on its own,
6441 and as the header isn't modified, each tagger <quote>sees</quote>
6445 Server-header taggers are executed before all other header actions
6446 that modify server headers. Their tags can be used to control
6447 all of the other server-header actions, the content filters
6448 and the crunch actions (<link linkend="redirect">redirect</link>
6449 and <link linkend="block">block</link>).
6452 Obviously crunching based on tags created by server-header taggers
6453 doesn't prevent the request from showing up in the server's log file.
6460 <term>Example usage (section):</term>
6464 # Tag every request with the content type declared by the server
6465 {+server-header-tagger{content-type}}
6476 <!-- ~~~~~ New section ~~~~~ -->
6477 <sect3 renderas="sect4" id="session-cookies-only">
6478 <title>session-cookies-only</title>
6482 <term>Typical use:</term>
6485 Allow only temporary <quote>session</quote> cookies (for the current
6486 browser session <emphasis>only</emphasis>).
6492 <term>Effect:</term>
6495 Deletes the <quote>expires</quote> field from <quote>Set-Cookie:</quote>
6496 server headers. Most browsers will not store such cookies permanently and
6497 forget them in between sessions.
6504 <!-- Boolean, Parameterized, Multi-value -->
6506 <para>Boolean.</para>
6511 <term>Parameter:</term>
6523 This is less strict than <literal><link linkend="crunch-incoming-cookies">crunch-incoming-cookies</link></literal> /
6524 <literal><link linkend="crunch-outgoing-cookies">crunch-outgoing-cookies</link></literal> and allows you to browse
6525 websites that insist or rely on setting cookies, without compromising your privacy too badly.
6528 Most browsers will not permanently store cookies that have been processed by
6529 <literal>session-cookies-only</literal> and will forget about them between sessions.
6530 This makes profiling cookies useless, but won't break sites which require cookies so
6531 that you can log in for transactions. This is generally turned on for all
6532 sites, and is the recommended setting.
6535 It makes <emphasis>no sense at all</emphasis> to use <literal>session-cookies-only</literal>
6536 together with <literal><link linkend="crunch-incoming-cookies">crunch-incoming-cookies</link></literal> or
6537 <literal><link linkend="crunch-outgoing-cookies">crunch-outgoing-cookies</link></literal>. If you do, cookies
6538 will be plainly killed.
6541 Note that it is up to the browser how it handles such cookies without an <quote>expires</quote>
6542 field. If you use an exotic browser, you might want to try it out to be sure.
6545 This setting also has no effect on cookies that may have been stored
6546 previously by the browser before starting <application>Privoxy</application>.
6547 These would have to be removed manually.
6550 <application>Privoxy</application> also uses
6551 the <link linkend="filter-content-cookies">content-cookies filter</link>
6552 to block some types of cookies. Content cookies are not effected by
6553 <literal>session-cookies-only</literal>.
6559 <term>Example usage:</term>
6562 <screen>+session-cookies-only</screen>
6570 <!-- ~~~~~ New section ~~~~~ -->
6571 <sect3 renderas="sect4" id="set-image-blocker">
6572 <title>set-image-blocker</title>
6576 <term>Typical use:</term>
6578 <para>Choose the replacement for blocked images</para>
6583 <term>Effect:</term>
6586 This action alone doesn't do anything noticeable. If <emphasis>both</emphasis>
6587 <literal><link linkend="block">block</link></literal> <emphasis>and</emphasis> <literal><link
6588 linkend="handle-as-image">handle-as-image</link></literal> <emphasis>also</emphasis>
6589 apply, i.e. if the request is to be blocked as an image,
6590 <emphasis>then</emphasis> the parameter of this action decides what will be
6591 sent as a replacement.
6598 <!-- Boolean, Parameterized, Multi-value -->
6600 <para>Parameterized.</para>
6605 <term>Parameter:</term>
6610 <quote>pattern</quote> to send a built-in checkerboard pattern image. The image is visually
6611 decent, scales very well, and makes it obvious where banners were busted.
6616 <quote>blank</quote> to send a built-in transparent image. This makes banners disappear
6617 completely, but makes it hard to detect where <application>Privoxy</application> has blocked
6618 images on a given page and complicates troubleshooting if <application>Privoxy</application>
6619 has blocked innocent images, like navigation icons.
6624 <quote><replaceable class="parameter">target-url</replaceable></quote> to
6625 send a redirect to <replaceable class="parameter">target-url</replaceable>. You can redirect
6626 to any image anywhere, even in your local filesystem via <quote>file:///</quote> URL.
6627 (But note that not all browsers support redirecting to a local file system).
6630 A good application of redirects is to use special <application>Privoxy</application>-built-in
6631 URLs, which send the built-in images, as <replaceable class="parameter">target-url</replaceable>.
6632 This has the same visual effect as specifying <quote>blank</quote> or <quote>pattern</quote> in
6633 the first place, but enables your browser to cache the replacement image, instead of requesting
6634 it over and over again.
6645 The URLs for the built-in images are <quote>http://config.privoxy.org/send-banner?type=<replaceable
6646 class="parameter">type</replaceable></quote>, where <replaceable class="parameter">type</replaceable> is
6647 either <quote>blank</quote> or <quote>pattern</quote>.
6650 There is a third (advanced) type, called <quote>auto</quote>. It is <emphasis>NOT</emphasis> to be
6651 used in <literal>set-image-blocker</literal>, but meant for use from <link linkend="filter-file">filters</link>.
6652 Auto will select the type of image that would have applied to the referring page, had it been an image.
6658 <term>Example usage:</term>
6664 <screen>+set-image-blocker{pattern}</screen>
6667 Redirect to the BSD daemon:
6670 <screen>+set-image-blocker{http://www.freebsd.org/gifs/dae_up3.gif}</screen>
6673 Redirect to the built-in pattern for better caching:
6676 <screen>+set-image-blocker{http://config.privoxy.org/send-banner?type=pattern}</screen>
6684 <!-- ~~~~~ New section ~~~~~ -->
6686 <title>Summary</title>
6688 Note that many of these actions have the potential to cause a page to
6689 misbehave, possibly even not to display at all. There are many ways
6690 a site designer may choose to design his site, and what HTTP header
6691 content, and other criteria, he may depend on. There is no way to have hard
6692 and fast rules for all sites. See the <link
6693 linkend="ACTIONSANAT">Appendix</link> for a brief example on troubleshooting
6699 <!-- ~~~~~ New section ~~~~~ -->
6700 <sect2 id="aliases">
6701 <title>Aliases</title>
6703 Custom <quote>actions</quote>, known to <application>Privoxy</application>
6704 as <quote>aliases</quote>, can be defined by combining other actions.
6705 These can in turn be invoked just like the built-in actions.
6706 Currently, an alias name can contain any character except space, tab,
6708 <quote>{</quote> and <quote>}</quote>, but we <emphasis>strongly
6709 recommend</emphasis> that you only use <quote>a</quote> to <quote>z</quote>,
6710 <quote>0</quote> to <quote>9</quote>, <quote>+</quote>, and <quote>-</quote>.
6711 Alias names are not case sensitive, and are not required to start with a
6712 <quote>+</quote> or <quote>-</quote> sign, since they are merely textually
6716 Aliases can be used throughout the actions file, but they <emphasis>must be
6717 defined in a special section at the top of the file!</emphasis>
6718 And there can only be one such section per actions file. Each actions file may
6719 have its own alias section, and the aliases defined in it are only visible
6723 There are two main reasons to use aliases: One is to save typing for frequently
6724 used combinations of actions, the other one is a gain in flexibility: If you
6725 decide once how you want to handle shops by defining an alias called
6726 <quote>shop</quote>, you can later change your policy on shops in
6727 <emphasis>one</emphasis> place, and your changes will take effect everywhere
6728 in the actions file where the <quote>shop</quote> alias is used. Calling aliases
6729 by their purpose also makes your actions files more readable.
6732 Currently, there is one big drawback to using aliases, though:
6733 <application>Privoxy</application>'s built-in web-based action file
6734 editor honors aliases when reading the actions files, but it expands
6735 them before writing. So the effects of your aliases are of course preserved,
6736 but the aliases themselves are lost when you edit sections that use aliases
6741 Now let's define some aliases...
6746 # Useful custom aliases we can use later.
6748 # Note the (required!) section header line and that this section
6749 # must be at the top of the actions file!
6753 # These aliases just save typing later:
6754 # (Note that some already use other aliases!)
6756 +crunch-all-cookies = +<link linkend="CRUNCH-INCOMING-COOKIES">crunch-incoming-cookies</link> +<link linkend="CRUNCH-OUTGOING-COOKIES">crunch-outgoing-cookies</link>
6757 -crunch-all-cookies = -<link linkend="CRUNCH-INCOMING-COOKIES">crunch-incoming-cookies</link> -<link linkend="CRUNCH-OUTGOING-COOKIES">crunch-outgoing-cookies</link>
6758 +block-as-image = +block{Blocked image.} +handle-as-image
6759 allow-all-cookies = -crunch-all-cookies -<link linkend="SESSION-COOKIES-ONLY">session-cookies-only</link> -<link linkend="FILTER-CONTENT-COOKIES">filter{content-cookies}</link>
6761 # These aliases define combinations of actions
6762 # that are useful for certain types of sites:
6764 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>
6766 shop = -crunch-all-cookies -<link linkend="FILTER-ALL-POPUPS">filter{all-popups}</link>
6768 # Short names for other aliases, for really lazy people ;-)
6770 c0 = +crunch-all-cookies
6771 c1 = -crunch-all-cookies</screen>
6775 ...and put them to use. These sections would appear in the lower part of an
6776 actions file and define exceptions to the default actions (as specified further
6777 up for the <quote>/</quote> pattern):
6782 # These sites are either very complex or very keen on
6783 # user data and require minimal interference to work:
6786 .office.microsoft.com
6787 .windowsupdate.microsoft.com
6788 # Gmail is really mail.google.com, not gmail.com
6792 # Allow cookies (for setting and retrieving your customer data)
6796 .worldpay.com # for quietpc.com
6799 # These shops require pop-ups:
6801 {-filter{all-popups} -filter{unsolicited-popups}}
6803 .overclockers.co.uk</screen>
6807 Aliases like <quote>shop</quote> and <quote>fragile</quote> are typically used for
6808 <quote>problem</quote> sites that require more than one action to be disabled
6809 in order to function properly.
6815 <!-- ~~~~~ New section ~~~~~ -->
6816 <sect2 id="act-examples">
6817 <title>Actions Files Tutorial</title>
6819 The above chapters have shown <link linkend="actions-file">which actions files
6820 there are and how they are organized</link>, how actions are <link
6821 linkend="actions">specified</link> and <link linkend="actions-apply">applied
6822 to URLs</link>, how <link linkend="af-patterns">patterns</link> work, and how to
6823 define and use <link linkend="aliases">aliases</link>. Now, let's look at an
6824 example <filename>match-all.action</filename>, <filename>default.action</filename>
6825 and <filename>user.action</filename> file and see how all these pieces come together:
6829 <title>match-all.action</title>
6831 Remember <emphasis>all actions are disabled when matching starts</emphasis>,
6832 so we have to explicitly enable the ones we want.
6836 While the <filename>match-all.action</filename> file only contains a
6837 single section, it is probably the most important one. It has only one
6838 pattern, <quote><literal>/</literal></quote>, but this pattern
6839 <link linkend="af-patterns">matches all URLs</link>. Therefore, the set of
6840 actions used in this <quote>default</quote> section <emphasis>will
6841 be applied to all requests as a start</emphasis>. It can be partly or
6842 wholly overridden by other actions files like <filename>default.action</filename>
6843 and <filename>user.action</filename>, but it will still be largely responsible
6844 for your overall browsing experience.
6848 Again, at the start of matching, all actions are disabled, so there is
6849 no need to disable any actions here. (Remember: a <quote>+</quote>
6850 preceding the action name enables the action, a <quote>-</quote> disables!).
6851 Also note how this long line has been made more readable by splitting it into
6852 multiple lines with line continuation.
6858 +<link linkend="CHANGE-X-FORWARDED-FOR">change-x-forwarded-for{block}</link> \
6859 +<link linkend="HIDE-FROM-HEADER">hide-from-header{block}</link> \
6860 +<link linkend="SET-IMAGE-BLOCKER">set-image-blocker{pattern}</link> \
6867 The default behavior is now set.
6872 <title>default.action</title>
6875 If you aren't a developer, there's no need for you to edit the
6876 <filename>default.action</filename> file. It is maintained by
6877 the &my-app; developers and if you disagree with some of the
6878 sections, you should overrule them in your <filename>user.action</filename>.
6882 Understanding the <filename>default.action</filename> file can
6883 help you with your <filename>user.action</filename>, though.
6887 The first section in this file is a special section for internal use
6888 that prevents older &my-app; versions from reading the file:
6893 ##########################################################################
6894 # Settings -- Don't change! For internal Privoxy use ONLY.
6895 ##########################################################################
6897 for-privoxy-version=3.0.11</screen>
6901 After that comes the (optional) alias section. We'll use the example
6902 section from the above <link linkend="aliases">chapter on aliases</link>,
6903 that also explains why and how aliases are used:
6908 ##########################################################################
6910 ##########################################################################
6913 # These aliases just save typing later:
6914 # (Note that some already use other aliases!)
6916 +crunch-all-cookies = +<link linkend="CRUNCH-INCOMING-COOKIES">crunch-incoming-cookies</link> +<link linkend="CRUNCH-OUTGOING-COOKIES">crunch-outgoing-cookies</link>
6917 -crunch-all-cookies = -<link linkend="CRUNCH-INCOMING-COOKIES">crunch-incoming-cookies</link> -<link linkend="CRUNCH-OUTGOING-COOKIES">crunch-outgoing-cookies</link>
6918 +block-as-image = +block{Blocked image.} +handle-as-image
6919 mercy-for-cookies = -crunch-all-cookies -<link linkend="SESSION-COOKIES-ONLY">session-cookies-only</link> -<link linkend="FILTER-CONTENT-COOKIES">filter{content-cookies}</link>
6921 # These aliases define combinations of actions
6922 # that are useful for certain types of sites:
6924 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>
6925 shop = -crunch-all-cookies -<link linkend="FILTER-ALL-POPUPS">filter{all-popups}</link></screen>
6929 The first of our specialized sections is concerned with <quote>fragile</quote>
6930 sites, i.e. sites that require minimum interference, because they are either
6931 very complex or very keen on tracking you (and have mechanisms in place that
6932 make them unusable for people who avoid being tracked). We will simply use
6933 our pre-defined <literal>fragile</literal> alias instead of stating the list
6934 of actions explicitly:
6939 ##########################################################################
6940 # Exceptions for sites that'll break under the default action set:
6941 ##########################################################################
6943 # "Fragile" Use a minimum set of actions for these sites (see alias above):
6946 .office.microsoft.com # surprise, surprise!
6947 .windowsupdate.microsoft.com
6948 mail.google.com</screen>
6952 Shopping sites are not as fragile, but they typically
6953 require cookies to log in, and pop-up windows for shopping
6954 carts or item details. Again, we'll use a pre-defined alias:
6963 .worldpay.com # for quietpc.com
6965 .scan.co.uk</screen>
6969 The <literal><link linkend="FAST-REDIRECTS">fast-redirects</link></literal>
6970 action, which may have been enabled in <filename>match-all.action</filename>,
6971 breaks some sites. So disable it for popular sites where we know it misbehaves:
6976 { -<link linkend="FAST-REDIRECTS">fast-redirects</link> }
6980 .altavista.com/.*(like|url|link):http
6981 .altavista.com/trans.*urltext=http
6982 .nytimes.com</screen>
6986 It is important that <application>Privoxy</application> knows which
6987 URLs belong to images, so that <emphasis>if</emphasis> they are to
6988 be blocked, a substitute image can be sent, rather than an HTML page.
6989 Contacting the remote site to find out is not an option, since it
6990 would destroy the loading time advantage of banner blocking, and it
6991 would feed the advertisers information about you. We can mark any
6992 URL as an image with the <literal><link
6993 linkend="handle-as-image">handle-as-image</link></literal> action,
6994 and marking all URLs that end in a known image file extension is a
7000 ##########################################################################
7002 ##########################################################################
7004 # Define which file types will be treated as images, in case they get
7005 # blocked further down this file:
7007 { +<link linkend="HANDLE-AS-IMAGE">handle-as-image</link> }
7008 /.*\.(gif|jpe?g|png|bmp|ico)$</screen>
7012 And then there are known banner sources. They often use scripts to
7013 generate the banners, so it won't be visible from the URL that the
7014 request is for an image. Hence we block them <emphasis>and</emphasis>
7015 mark them as images in one go, with the help of our
7016 <literal>+block-as-image</literal> alias defined above. (We could of
7017 course just as well use <literal>+<link linkend="block">block</link>
7018 +<link linkend="handle-as-image">handle-as-image</link></literal> here.)
7019 Remember that the type of the replacement image is chosen by the
7020 <literal><link linkend="set-image-blocker">set-image-blocker</link></literal>
7021 action. Since all URLs have matched the default section with its
7022 <literal>+<link linkend="set-image-blocker">set-image-blocker</link>{pattern}</literal>
7023 action before, it still applies and needn't be repeated:
7028 # Known ad generators:
7033 .ad.*.doubleclick.net
7034 .a.yimg.com/(?:(?!/i/).)*$
7035 .a[0-9].yimg.com/(?:(?!/i/).)*$
7041 One of the most important jobs of <application>Privoxy</application>
7042 is to block banners. Many of these can be <quote>blocked</quote>
7043 by the <literal><link linkend="filter">filter</link>{banners-by-size}</literal>
7044 action, which we enabled above, and which deletes the references to banner
7045 images from the pages while they are loaded, so the browser doesn't request
7046 them anymore, and hence they don't need to be blocked here. But this naturally
7047 doesn't catch all banners, and some people choose not to use filters, so we
7048 need a comprehensive list of patterns for banner URLs here, and apply the
7049 <literal><link linkend="block">block</link></literal> action to them.
7052 First comes many generic patterns, which do most of the work, by
7053 matching typical domain and path name components of banners. Then comes
7054 a list of individual patterns for specific sites, which is omitted here
7055 to keep the example short:
7060 ##########################################################################
7061 # Block these fine banners:
7062 ##########################################################################
7063 { <link linkend="BLOCK">+block{Banner ads.}</link> }
7071 /.*count(er)?\.(pl|cgi|exe|dll|asp|php[34]?)
7072 /(?:.*/)?(publicite|werbung|rekla(ma|me|am)|annonse|maino(kset|nta|s)?)/
7074 # Site-specific patterns (abbreviated):
7076 .hitbox.com</screen>
7080 It's quite remarkable how many advertisers actually call their banner
7081 servers ads.<replaceable>company</replaceable>.com, or call the directory
7082 in which the banners are stored simply <quote>banners</quote>. So the above
7083 generic patterns are surprisingly effective.
7086 But being very generic, they necessarily also catch URLs that we don't want
7087 to block. The pattern <literal>.*ads.</literal> e.g. catches
7088 <quote>nasty-<emphasis>ads</emphasis>.nasty-corp.com</quote> as intended,
7089 but also <quote>downlo<emphasis>ads</emphasis>.sourcefroge.net</quote> or
7090 <quote><emphasis>ads</emphasis>l.some-provider.net.</quote> So here come some
7091 well-known exceptions to the <literal>+<link linkend="BLOCK">block</link></literal>
7095 Note that these are exceptions to exceptions from the default! Consider the URL
7096 <quote>downloads.sourcefroge.net</quote>: Initially, all actions are deactivated,
7097 so it wouldn't get blocked. Then comes the defaults section, which matches the
7098 URL, but just deactivates the <literal><link linkend="BLOCK">block</link></literal>
7099 action once again. Then it matches <literal>.*ads.</literal>, an exception to the
7100 general non-blocking policy, and suddenly
7101 <literal><link linkend="BLOCK">+block</link></literal> applies. And now, it'll match
7102 <literal>.*loads.</literal>, where <literal><link linkend="BLOCK">-block</link></literal>
7103 applies, so (unless it matches <emphasis>again</emphasis> further down) it ends up
7104 with no <literal><link linkend="BLOCK">block</link></literal> action applying.
7109 ##########################################################################
7110 # Save some innocent victims of the above generic block patterns:
7111 ##########################################################################
7115 { -<link linkend="BLOCK">block</link> }
7116 adv[io]*. # (for advogato.org and advice.*)
7117 adsl. # (has nothing to do with ads)
7118 adobe. # (has nothing to do with ads either)
7119 ad[ud]*. # (adult.* and add.*)
7120 .edu # (universities don't host banners (yet!))
7121 .*loads. # (downloads, uploads etc)
7129 www.globalintersec.com/adv # (adv = advanced)
7130 www.ugu.com/sui/ugu/adv</screen>
7134 Filtering source code can have nasty side effects,
7135 so make an exception for our friends at sourceforge.net,
7136 and all paths with <quote>cvs</quote> in them. Note that
7137 <literal>-<link linkend="FILTER">filter</link></literal>
7138 disables <emphasis>all</emphasis> filters in one fell swoop!
7143 # Don't filter code!
7145 { -<link linkend="FILTER">filter</link> }
7150 .sourceforge.net</screen>
7154 The actual <filename>default.action</filename> is of course much more
7155 comprehensive, but we hope this example made clear how it works.
7160 <sect3><title>user.action</title>
7163 So far we are painting with a broad brush by setting general policies,
7164 which would be a reasonable starting point for many people. Now,
7165 you might want to be more specific and have customized rules that
7166 are more suitable to your personal habits and preferences. These would
7167 be for narrowly defined situations like your ISP or your bank, and should
7168 be placed in <filename>user.action</filename>, which is parsed after all other
7169 actions files and hence has the last word, over-riding any previously
7170 defined actions. <filename>user.action</filename> is also a
7171 <emphasis>safe</emphasis> place for your personal settings, since
7172 <filename>default.action</filename> is actively maintained by the
7173 <application>Privoxy</application> developers and you'll probably want
7174 to install updated versions from time to time.
7178 So let's look at a few examples of things that one might typically do in
7179 <filename>user.action</filename>:
7183 <!-- brief sample user.action here -->
7187 # My user.action file. <fred@example.com></screen>
7191 As <link linkend="aliases">aliases</link> are local to the actions
7192 file that they are defined in, you can't use the ones from
7193 <filename>default.action</filename>, unless you repeat them here:
7198 # Aliases are local to the file they are defined in.
7199 # (Re-)define aliases for this file:
7203 # These aliases just save typing later, and the alias names should
7204 # be self explanatory.
7206 +crunch-all-cookies = +crunch-incoming-cookies +crunch-outgoing-cookies
7207 -crunch-all-cookies = -crunch-incoming-cookies -crunch-outgoing-cookies
7208 allow-all-cookies = -crunch-all-cookies -session-cookies-only
7209 allow-popups = -filter{all-popups}
7210 +block-as-image = +block{Blocked as image.} +handle-as-image
7211 -block-as-image = -block
7213 # These aliases define combinations of actions that are useful for
7214 # certain types of sites:
7216 fragile = -block -crunch-all-cookies -filter -fast-redirects -hide-referrer
7217 shop = -crunch-all-cookies allow-popups
7219 # Allow ads for selected useful free sites:
7221 allow-ads = -block -filter{banners-by-size} -filter{banners-by-link}
7223 # Alias for specific file types that are text, but might have conflicting
7224 # MIME types. We want the browser to force these to be text documents.
7225 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>
7230 Say you have accounts on some sites that you visit regularly, and
7231 you don't want to have to log in manually each time. So you'd like
7232 to allow persistent cookies for these sites. The
7233 <literal>allow-all-cookies</literal> alias defined above does exactly
7234 that, i.e. it disables crunching of cookies in any direction, and the
7235 processing of cookies to make them only temporary.
7240 { allow-all-cookies }
7244 .redhat.com</screen>
7248 Your bank is allergic to some filter, but you don't know which, so you disable them all:
7253 { -<link linkend="FILTER">filter</link> }
7254 .your-home-banking-site.com</screen>
7258 Some file types you may not want to filter for various reasons:
7263 # Technical documentation is likely to contain strings that might
7264 # erroneously get altered by the JavaScript-oriented filters:
7269 # And this stupid host sends streaming video with a wrong MIME type,
7270 # so that Privoxy thinks it is getting HTML and starts filtering:
7272 stupid-server.example.com/</screen>
7276 Example of a simple <link linkend="BLOCK">block</link> action. Say you've
7277 seen an ad on your favourite page on example.com that you want to get rid of.
7278 You have right-clicked the image, selected <quote>copy image location</quote>
7279 and pasted the URL below while removing the leading http://, into a
7280 <literal>{ +block{} }</literal> section. Note that <literal>{ +handle-as-image
7281 }</literal> need not be specified, since all URLs ending in
7282 <literal>.gif</literal> will be tagged as images by the general rules as set
7283 in default.action anyway:
7288 { +<link linkend="BLOCK">block</link>{Nasty ads.} }
7289 www.example.com/nasty-ads/sponsor\.gif
7290 another.example.net/more/junk/here/</screen>
7294 The URLs of dynamically generated banners, especially from large banner
7295 farms, often don't use the well-known image file name extensions, which
7296 makes it impossible for <application>Privoxy</application> to guess
7297 the file type just by looking at the URL.
7298 You can use the <literal>+block-as-image</literal> alias defined above for
7300 Note that objects which match this rule but then turn out NOT to be an
7301 image are typically rendered as a <quote>broken image</quote> icon by the
7302 browser. Use cautiously.
7311 ar.atwola.com/</screen>
7315 Now you noticed that the default configuration breaks Forbes Magazine,
7316 but you were too lazy to find out which action is the culprit, and you
7317 were again too lazy to give <link linkend="contact">feedback</link>, so
7318 you just used the <literal>fragile</literal> alias on the site, and
7319 -- <emphasis>whoa!</emphasis> -- it worked. The <literal>fragile</literal>
7320 aliases disables those actions that are most likely to break a site. Also,
7321 good for testing purposes to see if it is <application>Privoxy</application>
7322 that is causing the problem or not. We later find other regular sites
7323 that misbehave, and add those to our personalized list of troublemakers:
7331 .mybank.com</screen>
7335 You like the <quote>fun</quote> text replacements in <filename>default.filter</filename>,
7336 but it is disabled in the distributed actions file.
7337 So you'd like to turn it on in your private,
7338 update-safe config, once and for all:
7343 { +<link linkend="filter-fun">filter{fun}</link> }
7344 / # For ALL sites!</screen>
7348 Note that the above is not really a good idea: There are exceptions
7349 to the filters in <filename>default.action</filename> for things that
7350 really shouldn't be filtered, like code on CVS->Web interfaces. Since
7351 <filename>user.action</filename> has the last word, these exceptions
7352 won't be valid for the <quote>fun</quote> filtering specified here.
7356 You might also worry about how your favourite free websites are
7357 funded, and find that they rely on displaying banner advertisements
7358 to survive. So you might want to specifically allow banners for those
7359 sites that you feel provide value to you:
7371 Note that <literal>allow-ads</literal> has been aliased to
7372 <literal>-<link linkend="block">block</link></literal>,
7373 <literal>-<link linkend="filter-banners-by-size">filter{banners-by-size}</link></literal>, and
7374 <literal>-<link linkend="filter-banners-by-link">filter{banners-by-link}</link></literal> above.
7378 Invoke another alias here to force an over-ride of the MIME type <literal>
7379 application/x-sh</literal> which typically would open a download type
7380 dialog. In my case, I want to look at the shell script, and then I can save
7381 it should I choose to.
7391 <filename>user.action</filename> is generally the best place to define
7392 exceptions and additions to the default policies of
7393 <filename>default.action</filename>. Some actions are safe to have their
7394 default policies set here though. So let's set a default policy to have a
7395 <quote>blank</quote> image as opposed to the checkerboard pattern for
7396 <emphasis>ALL</emphasis> sites. <quote>/</quote> of course matches all URL
7402 { +<link linkend="set-image-blocker">set-image-blocker{blank}</link> }
7403 / # ALL sites</screen>
7409 <!-- ~ End section ~ -->
7413 <!-- ~ End section ~ -->
7415 <!-- ~~~~~~~~ New section Header ~~~~~~~~~ -->
7417 <sect1 id="filter-file">
7418 <title>Filter Files</title>
7421 On-the-fly text substitutions need
7422 to be defined in a <quote>filter file</quote>. Once defined, they
7423 can then be invoked as an <quote>action</quote>.
7427 &my-app; supports three different filter actions:
7428 <literal><link linkend="filter">filter</link></literal> to
7429 rewrite the content that is send to the client,
7430 <literal><link linkend="client-header-filter">client-header-filter</link></literal>
7431 to rewrite headers that are send by the client, and
7432 <literal><link linkend="server-header-filter">server-header-filter</link></literal>
7433 to rewrite headers that are send by the server.
7437 &my-app; also supports two tagger actions:
7438 <literal><link linkend="client-header-tagger">client-header-tagger</link></literal>
7440 <literal><link linkend="server-header-tagger">server-header-tagger</link></literal>.
7441 Taggers and filters use the same syntax in the filter files, the difference
7442 is that taggers don't modify the text they are filtering, but use a rewritten
7443 version of the filtered text as tag. The tags can then be used to change the
7444 applying actions through sections with <link linkend="tag-pattern">tag-patterns</link>.
7449 Multiple filter files can be defined through the <literal> <link
7450 linkend="filterfile">filterfile</link></literal> config directive. The filters
7451 as supplied by the developers are located in
7452 <filename>default.filter</filename>. It is recommended that any locally
7453 defined or modified filters go in a separately defined file such as
7454 <filename>user.filter</filename>.
7458 Common tasks for content filters are to eliminate common annoyances in
7459 HTML and JavaScript, such as pop-up windows,
7460 exit consoles, crippled windows without navigation tools, the
7461 infamous <BLINK> tag etc, to suppress images with certain
7462 width and height attributes (standard banner sizes or web-bugs),
7463 or just to have fun.
7467 Enabled content filters are applied to any content whose
7468 <quote>Content Type</quote> header is recognised as a sign
7469 of text-based content, with the exception of <literal>text/plain</literal>.
7470 Use the <link linkend="FORCE-TEXT-MODE">force-text-mode</link> action
7471 to also filter other content.
7475 Substitutions are made at the source level, so if you want to <quote>roll
7476 your own</quote> filters, you should first be familiar with HTML syntax,
7477 and, of course, regular expressions.
7481 Just like the <link linkend="actions-file">actions files</link>, the
7482 filter file is organized in sections, which are called <emphasis>filters</emphasis>
7483 here. Each filter consists of a heading line, that starts with one of the
7484 <emphasis>keywords</emphasis> <literal>FILTER:</literal>,
7485 <literal>CLIENT-HEADER-FILTER:</literal> or <literal>SERVER-HEADER-FILTER:</literal>
7486 followed by the filter's <emphasis>name</emphasis>, and a short (one line)
7487 <emphasis>description</emphasis> of what it does. Below that line
7488 come the <emphasis>jobs</emphasis>, i.e. lines that define the actual
7489 text substitutions. By convention, the name of a filter
7490 should describe what the filter <emphasis>eliminates</emphasis>. The
7491 comment is used in the <ulink url="http://config.privoxy.org/">web-based
7492 user interface</ulink>.
7496 Once a filter called <replaceable>name</replaceable> has been defined
7497 in the filter file, it can be invoked by using an action of the form
7498 +<literal><link linkend="filter">filter</link>{<replaceable>name</replaceable>}</literal>
7499 in any <link linkend="actions-file">actions file</link>.
7503 Filter definitions start with a header line that contains the filter
7504 type, the filter name and the filter description.
7505 A content filter header line for a filter called <quote>foo</quote> could look
7510 <screen>FILTER: foo Replace all "foo" with "bar"</screen>
7514 Below that line, and up to the next header line, come the jobs that
7515 define what text replacements the filter executes. They are specified
7516 in a syntax that imitates <ulink url="http://www.perl.org/">Perl</ulink>'s
7517 <literal>s///</literal> operator. If you are familiar with Perl, you
7518 will find this to be quite intuitive, and may want to look at the
7519 PCRS documentation for the subtle differences to Perl behaviour. Most
7520 notably, the non-standard option letter <literal>U</literal> is supported,
7521 which turns the default to ungreedy matching.
7526 <ulink url="http://en.wikipedia.org/wiki/Regular_expressions"><quote>Regular
7527 Expressions</quote></ulink>, you might want to take a look at
7528 the <link linkend="regex">Appendix on regular expressions</link>, and
7529 see the <ulink url="http://perldoc.perl.org/perlre.html">Perl
7531 <ulink url="http://perldoc.perl.org/perlop.html">the
7532 <literal>s///</literal> operator's syntax</ulink> and <ulink
7533 url="http://perldoc.perl.org/perlre.html">Perl-style regular
7534 expressions</ulink> in general.
7535 The below examples might also help to get you started.
7539 <!-- ~~~~~~~~ New section Header ~~~~~~~~~ -->
7541 <sect2><title>Filter File Tutorial</title>
7543 Now, let's complete our <quote>foo</quote> content filter. We have already defined
7544 the heading, but the jobs are still missing. Since all it does is to replace
7545 <quote>foo</quote> with <quote>bar</quote>, there is only one (trivial) job
7550 <screen>s/foo/bar/</screen>
7554 But wait! Didn't the comment say that <emphasis>all</emphasis> occurrences
7555 of <quote>foo</quote> should be replaced? Our current job will only take
7556 care of the first <quote>foo</quote> on each page. For global substitution,
7557 we'll need to add the <literal>g</literal> option:
7561 <screen>s/foo/bar/g</screen>
7565 Our complete filter now looks like this:
7568 <screen>FILTER: foo Replace all "foo" with "bar"
7569 s/foo/bar/g</screen>
7573 Let's look at some real filters for more interesting examples. Here you see
7574 a filter that protects against some common annoyances that arise from JavaScript
7575 abuse. Let's look at its jobs one after the other:
7581 FILTER: js-annoyances Get rid of particularly annoying JavaScript abuse
7583 # Get rid of JavaScript referrer tracking. Test page: http://www.randomoddness.com/untitled.htm
7585 s|(<script.*)document\.referrer(.*</script>)|$1"Not Your Business!"$2|Usg</screen>
7589 Following the header line and a comment, you see the job. Note that it uses
7590 <literal>|</literal> as the delimiter instead of <literal>/</literal>, because
7591 the pattern contains a forward slash, which would otherwise have to be escaped
7592 by a backslash (<literal>\</literal>).
7596 Now, let's examine the pattern: it starts with the text <literal><script.*</literal>
7597 enclosed in parentheses. Since the dot matches any character, and <literal>*</literal>
7598 means: <quote>Match an arbitrary number of the element left of myself</quote>, this
7599 matches <quote><script</quote>, followed by <emphasis>any</emphasis> text, i.e.
7600 it matches the whole page, from the start of the first <script> tag.
7604 That's more than we want, but the pattern continues: <literal>document\.referrer</literal>
7605 matches only the exact string <quote>document.referrer</quote>. The dot needed to
7606 be <emphasis>escaped</emphasis>, i.e. preceded by a backslash, to take away its
7607 special meaning as a joker, and make it just a regular dot. So far, the meaning is:
7608 Match from the start of the first <script> tag in a the page, up to, and including,
7609 the text <quote>document.referrer</quote>, if <emphasis>both</emphasis> are present
7610 in the page (and appear in that order).
7614 But there's still more pattern to go. The next element, again enclosed in parentheses,
7615 is <literal>.*</script></literal>. You already know what <literal>.*</literal>
7616 means, so the whole pattern translates to: Match from the start of the first <script>
7617 tag in a page to the end of the last <script> tag, provided that the text
7618 <quote>document.referrer</quote> appears somewhere in between.
7622 This is still not the whole story, since we have ignored the options and the parentheses:
7623 The portions of the page matched by sub-patterns that are enclosed in parentheses, will be
7624 remembered and be available through the variables <literal>$1, $2, ...</literal> in
7625 the substitute. The <literal>U</literal> option switches to ungreedy matching, which means
7626 that the first <literal>.*</literal> in the pattern will only <quote>eat up</quote> all
7627 text in between <quote><script</quote> and the <emphasis>first</emphasis> occurrence
7628 of <quote>document.referrer</quote>, and that the second <literal>.*</literal> will
7629 only span the text up to the <emphasis>first</emphasis> <quote></script></quote>
7630 tag. Furthermore, the <literal>s</literal> option says that the match may span
7631 multiple lines in the page, and the <literal>g</literal> option again means that the
7632 substitution is global.
7636 So, to summarize, the pattern means: Match all scripts that contain the text
7637 <quote>document.referrer</quote>. Remember the parts of the script from
7638 (and including) the start tag up to (and excluding) the string
7639 <quote>document.referrer</quote> as <literal>$1</literal>, and the part following
7640 that string, up to and including the closing tag, as <literal>$2</literal>.
7644 Now the pattern is deciphered, but wasn't this about substituting things? So
7645 lets look at the substitute: <literal>$1"Not Your Business!"$2</literal> is
7646 easy to read: The text remembered as <literal>$1</literal>, followed by
7647 <literal>"Not Your Business!"</literal> (<emphasis>including</emphasis>
7648 the quotation marks!), followed by the text remembered as <literal>$2</literal>.
7649 This produces an exact copy of the original string, with the middle part
7650 (the <quote>document.referrer</quote>) replaced by <literal>"Not Your
7651 Business!"</literal>.
7655 The whole job now reads: Replace <quote>document.referrer</quote> by
7656 <literal>"Not Your Business!"</literal> wherever it appears inside a
7657 <script> tag. Note that this job won't break JavaScript syntax,
7658 since both the original and the replacement are syntactically valid
7659 string objects. The script just won't have access to the referrer
7660 information anymore.
7664 We'll show you two other jobs from the JavaScript taming department, but
7665 this time only point out the constructs of special interest:
7670 # The status bar is for displaying link targets, not pointless blahblah
7672 s/window\.status\s*=\s*(['"]).*?\1/dUmMy=1/ig</screen>
7676 <literal>\s</literal> stands for whitespace characters (space, tab, newline,
7677 carriage return, form feed), so that <literal>\s*</literal> means: <quote>zero
7678 or more whitespace</quote>. The <literal>?</literal> in <literal>.*?</literal>
7679 makes this matching of arbitrary text ungreedy. (Note that the <literal>U</literal>
7680 option is not set). The <literal>['"]</literal> construct means: <quote>a single
7681 <emphasis>or</emphasis> a double quote</quote>. Finally, <literal>\1</literal> is
7682 a back-reference to the first parenthesis just like <literal>$1</literal> above,
7683 with the difference that in the <emphasis>pattern</emphasis>, a backslash indicates
7684 a back-reference, whereas in the <emphasis>substitute</emphasis>, it's the dollar.
7688 So what does this job do? It replaces assignments of single- or double-quoted
7689 strings to the <quote>window.status</quote> object with a dummy assignment
7690 (using a variable name that is hopefully odd enough not to conflict with
7691 real variables in scripts). Thus, it catches many cases where e.g. pointless
7692 descriptions are displayed in the status bar instead of the link target when
7693 you move your mouse over links.
7698 # Kill OnUnload popups. Yummy. Test: http://www.zdnet.com/zdsubs/yahoo/tree/yfs.html
7700 s/(<body [^>]*)onunload(.*>)/$1never$2/iU</screen>
7705 <ulink url="http://www.w3.org/TR/2000/REC-DOM-Level-2-Events-20001113/events.html#Events-eventgroupings-htmlevents">OnUnload
7706 event binding</ulink> in the HTML DOM was a <emphasis>CRIME</emphasis>.
7707 When I close a browser window, I want it to close and die. Basta.
7708 This job replaces the <quote>onunload</quote> attribute in
7709 <quote><body></quote> tags with the dummy word <literal>never</literal>.
7710 Note that the <literal>i</literal> option makes the pattern matching
7711 case-insensitive. Also note that ungreedy matching alone doesn't always guarantee
7712 a minimal match: In the first parenthesis, we had to use <literal>[^>]*</literal>
7713 instead of <literal>.*</literal> to prevent the match from exceeding the
7714 <body> tag if it doesn't contain <quote>OnUnload</quote>, but the page's
7719 The last example is from the fun department:
7724 FILTER: fun Fun text replacements
7726 # Spice the daily news:
7728 s/microsoft(?!\.com)/MicroSuck/ig</screen>
7732 Note the <literal>(?!\.com)</literal> part (a so-called negative lookahead)
7733 in the job's pattern, which means: Don't match, if the string
7734 <quote>.com</quote> appears directly following <quote>microsoft</quote>
7735 in the page. This prevents links to microsoft.com from being trashed, while
7736 still replacing the word everywhere else.
7741 # Buzzword Bingo (example for extended regex syntax)
7743 s* industry[ -]leading \
7745 | customer[ -]focused \
7746 | market[ -]driven \
7747 | award[ -]winning # Comments are OK, too! \
7748 | high[ -]performance \
7749 | solutions[ -]based \
7753 *<font color="red"><b>BINGO!</b></font> \
7758 The <literal>x</literal> option in this job turns on extended syntax, and allows for
7759 e.g. the liberal use of (non-interpreted!) whitespace for nicer formatting.
7767 <!-- ~~~~~~~~ New section Header ~~~~~~~~~ -->
7769 <sect2 id="predefined-filters"><title>The Pre-defined Filters</title>
7773 Note each filter is also listed in the +filter action section above. Please
7774 keep these listings in sync.
7779 The distribution <filename>default.filter</filename> file contains a selection of
7780 pre-defined filters for your convenience:
7785 <term><emphasis>js-annoyances</emphasis></term>
7788 The purpose of this filter is to get rid of particularly annoying JavaScript abuse.
7793 replaces JavaScript references to the browser's referrer information
7794 with the string "Not Your Business!". This compliments the <literal><link
7795 linkend="hide-referrer">hide-referrer</link></literal> action on the content level.
7800 removes the bindings to the DOM's
7801 <ulink url="http://www.w3.org/TR/2000/REC-DOM-Level-2-Events-20001113/events.html#Events-eventgroupings-htmlevents">unload
7802 event</ulink> which we feel has no right to exist and is responsible for most <quote>exit consoles</quote>, i.e.
7803 nasty windows that pop up when you close another one.
7808 removes code that causes new windows to be opened with undesired properties, such as being
7809 full-screen, non-resizeable, without location, status or menu bar etc.
7815 Use with caution. This is an aggressive filter, and can break sites that
7816 rely heavily on JavaScript.
7822 <term><emphasis>js-events</emphasis></term>
7825 This is a very radical measure. It removes virtually all JavaScript event bindings, which
7826 means that scripts can not react to user actions such as mouse movements or clicks, window
7827 resizing etc, anymore. Use with caution!
7830 We <emphasis>strongly discourage</emphasis> using this filter as a default since it breaks
7831 many legitimate scripts. It is meant for use only on extra-nasty sites (should you really
7838 <term><emphasis>html-annoyances</emphasis></term>
7841 This filter will undo many common instances of HTML based abuse.
7844 The <literal>BLINK</literal> and <literal>MARQUEE</literal> tags
7845 are neutralized (yeah baby!), and browser windows will be created as
7846 resizeable (as of course they should be!), and will have location,
7847 scroll and menu bars -- even if specified otherwise.
7853 <term><emphasis>content-cookies</emphasis></term>
7856 Most cookies are set in the HTTP dialog, where they can be intercepted
7858 <literal><link linkend="crunch-incoming-cookies">crunch-incoming-cookies</link></literal>
7859 and <literal><link linkend="crunch-outgoing-cookies">crunch-outgoing-cookies</link></literal>
7860 actions. But web sites increasingly make use of HTML meta tags and JavaScript
7861 to sneak cookies to the browser on the content level.
7864 This filter disables most HTML and JavaScript code that reads or sets
7865 cookies. It cannot detect all clever uses of these types of code, so it
7866 should not be relied on as an absolute fix. Use it wherever you would also
7867 use the cookie crunch actions.
7873 <term><emphasis>refresh-tags</emphasis></term>
7876 Disable any refresh tags if the interval is greater than nine seconds (so
7877 that redirections done via refresh tags are not destroyed). This is useful
7878 for dial-on-demand setups, or for those who find this HTML feature
7885 <term><emphasis>unsolicited-popups</emphasis></term>
7888 This filter attempts to prevent only <quote>unsolicited</quote> pop-up
7889 windows from opening, yet still allow pop-up windows that the user
7890 has explicitly chosen to open. It was added in version 3.0.1,
7891 as an improvement over earlier such filters.
7894 Technical note: The filter works by redefining the window.open JavaScript
7895 function to a dummy function, <literal>PrivoxyWindowOpen()</literal>,
7896 during the loading and rendering phase of each HTML page access, and
7897 restoring the function afterward.
7900 This is recommended only for browsers that cannot perform this function
7901 reliably themselves. And be aware that some sites require such windows
7902 in order to function normally. Use with caution.
7908 <term><emphasis>all-popups</emphasis></term>
7911 Attempt to prevent <emphasis>all</emphasis> pop-up windows from opening.
7912 Note this should be used with even more discretion than the above, since
7913 it is more likely to break some sites that require pop-ups for normal
7914 usage. Use with caution.
7920 <term><emphasis>img-reorder</emphasis></term>
7923 This is a helper filter that has no value if used alone. It makes the
7924 <literal>banners-by-size</literal> and <literal>banners-by-link</literal>
7925 (see below) filters more effective and should be enabled together with them.
7931 <term><emphasis>banners-by-size</emphasis></term>
7934 This filter removes image tags purely based on what size they are. Fortunately
7935 for us, many ads and banner images tend to conform to certain standardized
7936 sizes, which makes this filter quite effective for ad stripping purposes.
7939 Occasionally this filter will cause false positives on images that are not ads,
7940 but just happen to be of one of the standard banner sizes.
7943 Recommended only for those who require extreme ad blocking. The default
7944 block rules should catch 95+% of all ads <emphasis>without</emphasis> this filter enabled.
7950 <term><emphasis>banners-by-link</emphasis></term>
7953 This is an experimental filter that attempts to kill any banners if
7954 their URLs seem to point to known or suspected click trackers. It is currently
7955 not of much value and is not recommended for use by default.
7961 <term><emphasis>webbugs</emphasis></term>
7964 Webbugs are small, invisible images (technically 1X1 GIF images), that
7965 are used to track users across websites, and collect information on them.
7966 As an HTML page is loaded by the browser, an embedded image tag causes the
7967 browser to contact a third-party site, disclosing the tracking information
7968 through the requested URL and/or cookies for that third-party domain, without
7969 the user ever becoming aware of the interaction with the third-party site.
7970 HTML-ized spam also uses a similar technique to verify email addresses.
7973 This filter removes the HTML code that loads such <quote>webbugs</quote>.
7979 <term><emphasis>tiny-textforms</emphasis></term>
7982 A rather special-purpose filter that can be used to enlarge textareas (those
7983 multi-line text boxes in web forms) and turn off hard word wrap in them.
7984 It was written for the sourceforge.net tracker system where such boxes are
7985 a nuisance, but it can be handy on other sites, too.
7988 It is not recommended to use this filter as a default.
7994 <term><emphasis>jumping-windows</emphasis></term>
7997 Many consider windows that move, or resize themselves to be abusive. This filter
7998 neutralizes the related JavaScript code. Note that some sites might not display
7999 or behave as intended when using this filter. Use with caution.
8005 <term><emphasis>frameset-borders</emphasis></term>
8008 Some web designers seem to assume that everyone in the world will view their
8009 web sites using the same browser brand and version, screen resolution etc,
8010 because only that assumption could explain why they'd use static frame sizes,
8011 yet prevent their frames from being resized by the user, should they be too
8012 small to show their whole content.
8015 This filter removes the related HTML code. It should only be applied to sites
8022 <term><emphasis>demoronizer</emphasis></term>
8025 Many Microsoft products that generate HTML use non-standard extensions (read:
8026 violations) of the ISO 8859-1 aka Latin-1 character set. This can cause those
8027 HTML documents to display with errors on standard-compliant platforms.
8030 This filter translates the MS-only characters into Latin-1 equivalents.
8031 It is not necessary when using MS products, and will cause corruption of
8032 all documents that use 8-bit character sets other than Latin-1. It's mostly
8033 worthwhile for Europeans on non-MS platforms, if weird garbage characters
8034 sometimes appear on some pages, or user agents that don't correct for this on
8037 My version of Mozilla (ancient) shows litte square boxes for quote
8038 characters, and apostrophes on moronized pages. So many pages have this, I
8039 can read them fine now. HB 08/27/06
8046 <term><emphasis>shockwave-flash</emphasis></term>
8049 A filter for shockwave haters. As the name suggests, this filter strips code
8050 out of web pages that is used to embed shockwave flash objects.
8058 <term><emphasis>quicktime-kioskmode</emphasis></term>
8061 Change HTML code that embeds Quicktime objects so that kioskmode, which
8062 prevents saving, is disabled.
8068 <term><emphasis>fun</emphasis></term>
8071 Text replacements for subversive browsing fun. Make fun of your favorite
8072 Monopolist or play buzzword bingo.
8078 <term><emphasis>crude-parental</emphasis></term>
8081 A demonstration-only filter that shows how <application>Privoxy</application>
8082 can be used to delete web content on a keyword basis.
8088 <term><emphasis>ie-exploits</emphasis></term>
8091 An experimental collection of text replacements to disable malicious HTML and JavaScript
8092 code that exploits known security holes in Internet Explorer.
8095 Presently, it only protects against Nimda and a cross-site scripting bug, and
8096 would need active maintenance to provide more substantial protection.
8102 <term><emphasis>site-specifics</emphasis></term>
8105 Some web sites have very specific problems, the cure for which doesn't apply
8106 anywhere else, or could even cause damage on other sites.
8109 This is a collection of such site-specific cures which should only be applied
8110 to the sites they were intended for, which is what the supplied
8111 <filename>default.action</filename> file does. Users shouldn't need to change
8112 anything regarding this filter.
8118 <term><emphasis>google</emphasis></term>
8121 A CSS based block for Google text ads. Also removes a width limitation
8122 and the toolbar advertisement.
8128 <term><emphasis>yahoo</emphasis></term>
8131 Another CSS based block, this time for Yahoo text ads. And removes
8132 a width limitation as well.
8138 <term><emphasis>msn</emphasis></term>
8141 Another CSS based block, this time for MSN text ads. And removes
8142 tracking URLs, as well as a width limitation.
8148 <term><emphasis>blogspot</emphasis></term>
8151 Cleans up some Blogspot blogs. Read the fine print before using this one!
8154 This filter also intentionally removes some navigation stuff and sets the
8155 page width to 100%. As a result, some rounded <quote>corners</quote> would
8156 appear to early or not at all and as fixing this would require a browser
8157 that understands background-size (CSS3), they are removed instead.
8163 <term><emphasis>xml-to-html</emphasis></term>
8166 Server-header filter to change the Content-Type from xml to html.
8172 <term><emphasis>html-to-xml</emphasis></term>
8175 Server-header filter to change the Content-Type from html to xml.
8181 <term><emphasis>no-ping</emphasis></term>
8184 Removes the non-standard <literal>ping</literal> attribute from
8185 anchor and area HTML tags.
8191 <term><emphasis>hide-tor-exit-notation</emphasis></term>
8194 Client-header filter to remove the <command>Tor</command> exit node notation
8195 found in Host and Referer headers.
8198 If &my-app; and <command>Tor</command> are chained and &my-app;
8199 is configured to use socks4a, one can use <quote>http://www.example.org.foobar.exit/</quote>
8200 to access the host <quote>www.example.org</quote> through the
8201 <command>Tor</command> exit node <quote>foobar</quote>.
8204 As the HTTP client isn't aware of this notation, it treats the
8205 whole string <quote>www.example.org.foobar.exit</quote> as host and uses it
8206 for the <quote>Host</quote> and <quote>Referer</quote> headers. From the
8207 server's point of view the resulting headers are invalid and can cause problems.
8210 An invalid <quote>Referer</quote> header can trigger <quote>hot-linking</quote>
8211 protections, an invalid <quote>Host</quote> header will make it impossible for
8212 the server to find the right vhost (several domains hosted on the same IP address).
8215 This client-header filter removes the <quote>foo.exit</quote> part in those headers
8216 to prevent the mentioned problems. Note that it only modifies
8217 the HTTP headers, it doesn't make it impossible for the server
8218 to detect your <command>Tor</command> exit node based on the IP address
8219 the request is coming from.
8226 <term><emphasis> </emphasis></term>
8240 <!-- ~ End section ~ -->
8244 <!-- ~~~~~ New section ~~~~~ -->
8246 <sect1 id="templates">
8247 <title>Privoxy's Template Files</title>
8249 All <application>Privoxy</application> built-in pages, i.e. error pages such as the
8250 <ulink url="http://show-the-404-error.page"><quote>404 - No Such Domain</quote>
8251 error page</ulink>, the <ulink
8252 url="http://ads.bannerserver.example.com/nasty-ads/sponsor.html"><quote>BLOCKED</quote>
8254 and all pages of its <ulink url="http://config.privoxy.org/">web-based
8255 user interface</ulink>, are generated from <emphasis>templates</emphasis>.
8256 (<application>Privoxy</application> must be running for the above links to work as
8261 These templates are stored in a subdirectory of the <link linkend="confdir">configuration
8262 directory</link> called <filename>templates</filename>. On Unixish platforms,
8264 <ulink url="file:///etc/privoxy/templates/"><filename>/etc/privoxy/templates/</filename></ulink>.
8268 The templates are basically normal HTML files, but with place-holders (called symbols
8269 or exports), which <application>Privoxy</application> fills at run time. It
8270 is possible to edit the templates with a normal text editor, should you want
8271 to customize them. (<emphasis>Not recommended for the casual
8272 user</emphasis>). Should you create your own custom templates, you should use
8273 the <filename>config</filename> setting <link linkend="templdir">templdir</link>
8274 to specify an alternate location, so your templates do not get overwritten
8278 Note that just like in configuration files, lines starting
8279 with <literal>#</literal> are ignored when the templates are filled in.
8283 The place-holders are of the form <literal>@name@</literal>, and you will
8284 find a list of available symbols, which vary from template to template,
8285 in the comments at the start of each file. Note that these comments are not
8286 always accurate, and that it's probably best to look at the existing HTML
8287 code to find out which symbols are supported and what they are filled in with.
8291 A special application of this substitution mechanism is to make whole
8292 blocks of HTML code disappear when a specific symbol is set. We use this
8293 for many purposes, one of them being to include the beta warning in all
8294 our user interface (CGI) pages when <application>Privoxy</application>
8295 is in an alpha or beta development stage:
8300 <!-- @if-unstable-start -->
8302 ... beta warning HTML code goes here ...
8304 <!-- if-unstable-end@ --></screen>
8308 If the "unstable" symbol is set, everything in between and including
8309 <literal>@if-unstable-start</literal> and <literal>if-unstable-end@</literal>
8310 will disappear, leaving nothing but an empty comment:
8314 <screen><!-- --></screen>
8318 There's also an if-then-else construct and an <literal>#include</literal>
8319 mechanism, but you'll sure find out if you are inclined to edit the
8324 All templates refer to a style located at
8325 <ulink url="http://config.privoxy.org/send-stylesheet"><literal>http://config.privoxy.org/send-stylesheet</literal></ulink>.
8326 This is, of course, locally served by <application>Privoxy</application>
8327 and the source for it can be found and edited in the
8328 <filename>cgi-style.css</filename> template.
8333 <!-- ~ End section ~ -->
8337 <!-- ~~~~~ New section ~~~~~ -->
8339 <sect1 id="contact"><title>Contacting the Developers, Bug Reporting and Feature
8342 <!-- Include contacting.sgml boilerplate: -->
8344 <!-- end boilerplate -->
8348 <!-- ~ End section ~ -->
8351 <!-- ~~~~~ New section ~~~~~ -->
8352 <sect1 id="copyright"><title>Privoxy Copyright, License and History</title>
8354 <!-- Include copyright.sgml: -->
8356 <!-- end copyright -->
8358 <!-- ~~~~~ New section ~~~~~ -->
8359 <sect2><title>License</title>
8360 <!-- Include copyright.sgml: -->
8362 <!-- end copyright -->
8364 <!-- ~ End section ~ -->
8367 <!-- ~~~~~ New section ~~~~~ -->
8369 <sect2 id="history"><title>History</title>
8370 <!-- Include history.sgml: -->
8372 <!-- end history -->
8375 <sect2 id="authors"><title>Authors</title>
8376 <!-- Include p-authors.sgml: -->
8378 <!-- end authors -->
8383 <!-- ~ End section ~ -->
8386 <!-- ~~~~~ New section ~~~~~ -->
8387 <sect1 id="seealso"><title>See Also</title>
8388 <!-- Include seealso.sgml: -->
8390 <!-- end seealso -->
8395 <!-- ~~~~~ New section ~~~~~ -->
8396 <sect1 id="appendix"><title>Appendix</title>
8399 <!-- ~~~~~ New section ~~~~~ -->
8401 <title>Regular Expressions</title>
8403 <application>Privoxy</application> uses Perl-style <quote>regular
8404 expressions</quote> in its <link linkend="actions-file">actions
8405 files</link> and <link linkend="filter-file">filter file</link>,
8406 through the <ulink url="http://www.pcre.org/">PCRE</ulink> and
8409 <ulink url="http://www.oesterhelt.org/pcrs/">PCRS</ulink> libraries.
8411 <application>PCRS</application> libraries.
8415 If you are reading this, you probably don't understand what <quote>regular
8416 expressions</quote> are, or what they can do. So this will be a very brief
8417 introduction only. A full explanation would require a <ulink
8418 url="http://www.oreilly.com/catalog/regex/">book</ulink> ;-)
8422 Regular expressions provide a language to describe patterns that can be
8423 run against strings of characters (letter, numbers, etc), to see if they
8424 match the string or not. The patterns are themselves (sometimes complex)
8425 strings of literal characters, combined with wild-cards, and other special
8426 characters, called meta-characters. The <quote>meta-characters</quote> have
8427 special meanings and are used to build complex patterns to be matched against.
8428 Perl Compatible Regular Expressions are an especially convenient
8429 <quote>dialect</quote> of the regular expression language.
8433 To make a simple analogy, we do something similar when we use wild-card
8434 characters when listing files with the <command>dir</command> command in DOS.
8435 <literal>*.*</literal> matches all filenames. The <quote>special</quote>
8436 character here is the asterisk which matches any and all characters. We can be
8437 more specific and use <literal>?</literal> to match just individual
8438 characters. So <quote>dir file?.text</quote> would match
8439 <quote>file1.txt</quote>, <quote>file2.txt</quote>, etc. We are pattern
8440 matching, using a similar technique to <quote>regular expressions</quote>!
8444 Regular expressions do essentially the same thing, but are much, much more
8445 powerful. There are many more <quote>special characters</quote> and ways of
8446 building complex patterns however. Let's look at a few of the common ones,
8447 and then some examples:
8452 <emphasis>.</emphasis> - Matches any single character, e.g. <quote>a</quote>,
8453 <quote>A</quote>, <quote>4</quote>, <quote>:</quote>, or <quote>@</quote>.
8455 </simplelist></para>
8459 <emphasis>?</emphasis> - The preceding character or expression is matched ZERO or ONE
8462 </simplelist></para>
8466 <emphasis>+</emphasis> - The preceding character or expression is matched ONE or MORE
8469 </simplelist></para>
8473 <emphasis>*</emphasis> - The preceding character or expression is matched ZERO or MORE
8476 </simplelist></para>
8480 <emphasis>\</emphasis> - The <quote>escape</quote> character denotes that
8481 the following character should be taken literally. This is used where one of the
8482 special characters (e.g. <quote>.</quote>) needs to be taken literally and
8483 not as a special meta-character. Example: <quote>example\.com</quote>, makes
8484 sure the period is recognized only as a period (and not expanded to its
8485 meta-character meaning of any single character).
8487 </simplelist></para>
8491 <emphasis>[ ]</emphasis> - Characters enclosed in brackets will be matched if
8492 any of the enclosed characters are encountered. For instance, <quote>[0-9]</quote>
8493 matches any numeric digit (zero through nine). As an example, we can combine
8494 this with <quote>+</quote> to match any digit one of more times: <quote>[0-9]+</quote>.
8496 </simplelist></para>
8500 <emphasis>( )</emphasis> - parentheses are used to group a sub-expression,
8501 or multiple sub-expressions.
8503 </simplelist></para>
8507 <emphasis>|</emphasis> - The <quote>bar</quote> character works like an
8508 <quote>or</quote> conditional statement. A match is successful if the
8509 sub-expression on either side of <quote>|</quote> matches. As an example:
8510 <quote>/(this|that) example/</quote> uses grouping and the bar character
8511 and would match either <quote>this example</quote> or <quote>that
8512 example</quote>, and nothing else.
8514 </simplelist></para>
8517 These are just some of the ones you are likely to use when matching URLs with
8518 <application>Privoxy</application>, and is a long way from a definitive
8519 list. This is enough to get us started with a few simple examples which may
8520 be more illuminating:
8524 <emphasis><literal>/.*/banners/.*</literal></emphasis> - A simple example
8525 that uses the common combination of <quote>.</quote> and <quote>*</quote> to
8526 denote any character, zero or more times. In other words, any string at all.
8527 So we start with a literal forward slash, then our regular expression pattern
8528 (<quote>.*</quote>) another literal forward slash, the string
8529 <quote>banners</quote>, another forward slash, and lastly another
8530 <quote>.*</quote>. We are building
8531 a directory path here. This will match any file with the path that has a
8532 directory named <quote>banners</quote> in it. The <quote>.*</quote> matches
8533 any characters, and this could conceivably be more forward slashes, so it
8534 might expand into a much longer looking path. For example, this could match:
8535 <quote>/eye/hate/spammers/banners/annoy_me_please.gif</quote>, or just
8536 <quote>/banners/annoying.html</quote>, or almost an infinite number of other
8537 possible combinations, just so it has <quote>banners</quote> in the path
8542 And now something a little more complex:
8546 <emphasis><literal>/.*/adv((er)?ts?|ertis(ing|ements?))?/</literal></emphasis> -
8547 We have several literal forward slashes again (<quote>/</quote>), so we are
8548 building another expression that is a file path statement. We have another
8549 <quote>.*</quote>, so we are matching against any conceivable sub-path, just so
8550 it matches our expression. The only true literal that <emphasis>must
8551 match</emphasis> our pattern is <application>adv</application>, together with
8552 the forward slashes. What comes after the <quote>adv</quote> string is the
8557 Remember the <quote>?</quote> means the preceding expression (either a
8558 literal character or anything grouped with <quote>(...)</quote> in this case)
8559 can exist or not, since this means either zero or one match. So
8560 <quote>((er)?ts?|ertis(ing|ements?))</quote> is optional, as are the
8561 individual sub-expressions: <quote>(er)</quote>,
8562 <quote>(ing|ements?)</quote>, and the <quote>s</quote>. The <quote>|</quote>
8563 means <quote>or</quote>. We have two of those. For instance,
8564 <quote>(ing|ements?)</quote>, can expand to match either <quote>ing</quote>
8565 <emphasis>OR</emphasis> <quote>ements?</quote>. What is being done here, is an
8566 attempt at matching as many variations of <quote>advertisement</quote>, and
8567 similar, as possible. So this would expand to match just <quote>adv</quote>,
8568 or <quote>advert</quote>, or <quote>adverts</quote>, or
8569 <quote>advertising</quote>, or <quote>advertisement</quote>, or
8570 <quote>advertisements</quote>. You get the idea. But it would not match
8571 <quote>advertizements</quote> (with a <quote>z</quote>). We could fix that by
8572 changing our regular expression to:
8573 <quote>/.*/adv((er)?ts?|erti(s|z)(ing|ements?))?/</quote>, which would then match
8578 <emphasis><literal>/.*/advert[0-9]+\.(gif|jpe?g)</literal></emphasis> - Again
8579 another path statement with forward slashes. Anything in the square brackets
8580 <quote>[ ]</quote> can be matched. This is using <quote>0-9</quote> as a
8581 shorthand expression to mean any digit one through nine. It is the same as
8582 saying <quote>0123456789</quote>. So any digit matches. The <quote>+</quote>
8583 means one or more of the preceding expression must be included. The preceding
8584 expression here is what is in the square brackets -- in this case, any digit
8585 one through nine. Then, at the end, we have a grouping: <quote>(gif|jpe?g)</quote>.
8586 This includes a <quote>|</quote>, so this needs to match the expression on
8587 either side of that bar character also. A simple <quote>gif</quote> on one side, and the other
8588 side will in turn match either <quote>jpeg</quote> or <quote>jpg</quote>,
8589 since the <quote>?</quote> means the letter <quote>e</quote> is optional and
8590 can be matched once or not at all. So we are building an expression here to
8591 match image GIF or JPEG type image file. It must include the literal
8592 string <quote>advert</quote>, then one or more digits, and a <quote>.</quote>
8593 (which is now a literal, and not a special character, since it is escaped
8594 with <quote>\</quote>), and lastly either <quote>gif</quote>, or
8595 <quote>jpeg</quote>, or <quote>jpg</quote>. Some possible matches would
8596 include: <quote>//advert1.jpg</quote>,
8597 <quote>/nasty/ads/advert1234.gif</quote>,
8598 <quote>/banners/from/hell/advert99.jpg</quote>. It would not match
8599 <quote>advert1.gif</quote> (no leading slash), or
8600 <quote>/adverts232.jpg</quote> (the expression does not include an
8601 <quote>s</quote>), or <quote>/advert1.jsp</quote> (<quote>jsp</quote> is not
8602 in the expression anywhere).
8606 We are barely scratching the surface of regular expressions here so that you
8607 can understand the default <application>Privoxy</application>
8608 configuration files, and maybe use this knowledge to customize your own
8609 installation. There is much, much more that can be done with regular
8610 expressions. Now that you know enough to get started, you can learn more on
8615 More reading on Perl Compatible Regular expressions:
8616 <ulink url="http://perldoc.perl.org/perlre.html">http://perldoc.perl.org/perlre.html</ulink>
8620 For information on regular expression based substitutions and their applications
8621 in filters, please see the <link linkend="filter-file">filter file tutorial</link>
8626 <!-- ~ End section ~ -->
8629 <!-- ~~~~~ New section ~~~~~ -->
8631 <title>Privoxy's Internal Pages</title>
8634 Since <application>Privoxy</application> proxies each requested
8635 web page, it is easy for <application>Privoxy</application> to
8636 trap certain special URLs. In this way, we can talk directly to
8637 <application>Privoxy</application>, and see how it is
8638 configured, see how our rules are being applied, change these
8639 rules and other configuration options, and even turn
8640 <application>Privoxy's</application> filtering off, all with
8646 The URLs listed below are the special ones that allow direct access
8647 to <application>Privoxy</application>. Of course,
8648 <application>Privoxy</application> must be running to access these. If
8649 not, you will get a friendly error message. Internet access is not
8662 <ulink url="http://config.privoxy.org/">http://config.privoxy.org/</ulink>
8666 There is a shortcut: <ulink url="http://p.p/">http://p.p/</ulink> (But it
8667 doesn't provide a fall-back to a real page, in case the request is not
8668 sent through <application>Privoxy</application>)
8674 Show information about the current configuration, including viewing and
8675 editing of actions files:
8679 <ulink url="http://config.privoxy.org/show-status">http://config.privoxy.org/show-status</ulink>
8686 Show the source code version numbers:
8690 <ulink url="http://config.privoxy.org/show-version">http://config.privoxy.org/show-version</ulink>
8697 Show the browser's request headers:
8701 <ulink url="http://config.privoxy.org/show-request">http://config.privoxy.org/show-request</ulink>
8708 Show which actions apply to a URL and why:
8712 <ulink url="http://config.privoxy.org/show-url-info">http://config.privoxy.org/show-url-info</ulink>
8719 Toggle Privoxy on or off. This feature can be turned off/on in the main
8720 <filename>config</filename> file. When toggled <quote>off</quote>, <quote>Privoxy</quote>
8721 continues to run, but only as a pass-through proxy, with no actions taking
8726 <ulink url="http://config.privoxy.org/toggle">http://config.privoxy.org/toggle</ulink>
8730 Short cuts. Turn off, then on:
8734 <ulink url="http://config.privoxy.org/toggle?set=disable">http://config.privoxy.org/toggle?set=disable</ulink>
8739 <ulink url="http://config.privoxy.org/toggle?set=enable">http://config.privoxy.org/toggle?set=enable</ulink>
8748 These may be bookmarked for quick reference. See next.
8752 <sect3 id="bookmarklets">
8753 <title>Bookmarklets</title>
8755 Below are some <quote>bookmarklets</quote> to allow you to easily access a
8756 <quote>mini</quote> version of some of <application>Privoxy's</application>
8757 special pages. They are designed for MS Internet Explorer, but should work
8758 equally well in Netscape, Mozilla, and other browsers which support
8759 JavaScript. They are designed to run directly from your bookmarks - not by
8760 clicking the links below (although that should work for testing).
8763 To save them, right-click the link and choose <quote>Add to Favorites</quote>
8764 (IE) or <quote>Add Bookmark</quote> (Netscape). You will get a warning that
8765 the bookmark <quote>may not be safe</quote> - just click OK. Then you can run the
8766 Bookmarklet directly from your favorites/bookmarks. For even faster access,
8767 you can put them on the <quote>Links</quote> bar (IE) or the <quote>Personal
8768 Toolbar</quote> (Netscape), and run them with a single click.
8777 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>
8784 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>
8791 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)
8798 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>
8804 <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>
8810 <ulink url="javascript:void(window.open('http://config.privoxy.org/show-url-info?url='+escape(location.href),'Why').focus());">Privoxy - Why?</ulink>
8817 Credit: The site which gave us the general idea for these bookmarklets is
8818 <ulink url="http://www.bookmarklets.com/">www.bookmarklets.com</ulink>. They
8819 have more information about bookmarklets.
8828 <!-- ~~~~~ New section ~~~~~ -->
8830 <title>Chain of Events</title>
8832 Let's take a quick look at how some of <application>Privoxy's</application>
8833 core features are triggered, and the ensuing sequence of events when a web
8834 page is requested by your browser:
8841 First, your web browser requests a web page. The browser knows to send
8842 the request to <application>Privoxy</application>, which will in turn,
8843 relay the request to the remote web server after passing the following
8849 <application>Privoxy</application> traps any request for its own internal CGI
8850 pages (e.g <ulink url="http://p.p/">http://p.p/</ulink>) and sends the CGI page back to the browser.
8855 Next, <application>Privoxy</application> checks to see if the URL
8857 linkend="BLOCK"><quote>+block</quote></link> patterns. If
8858 so, the URL is then blocked, and the remote web server will not be contacted.
8859 <link linkend="HANDLE-AS-IMAGE"><quote>+handle-as-image</quote></link>
8861 <link linkend="HANDLE-AS-EMPTY-DOCUMENT"><quote>+handle-as-empty-document</quote></link>
8862 are then checked, and if there is no match, an
8863 HTML <quote>BLOCKED</quote> page is sent back to the browser. Otherwise, if
8864 it does match, an image is returned for the former, and an empty text
8865 document for the latter. The type of image would depend on the setting of
8866 <link linkend="SET-IMAGE-BLOCKER"><quote>+set-image-blocker</quote></link>
8867 (blank, checkerboard pattern, or an HTTP redirect to an image elsewhere).
8872 Untrusted URLs are blocked. If URLs are being added to the
8873 <filename>trust</filename> file, then that is done.
8878 If the URL pattern matches the <link
8879 linkend="FAST-REDIRECTS"><quote>+fast-redirects</quote></link> action,
8880 it is then processed. Unwanted parts of the requested URL are stripped.
8885 Now the rest of the client browser's request headers are processed. If any
8886 of these match any of the relevant actions (e.g. <link
8887 linkend="HIDE-USER-AGENT"><quote>+hide-user-agent</quote></link>,
8888 etc.), headers are suppressed or forged as determined by these actions and
8894 Now the web server starts sending its response back (i.e. typically a web
8900 First, the server headers are read and processed to determine, among other
8901 things, the MIME type (document type) and encoding. The headers are then
8902 filtered as determined by the
8903 <link linkend="CRUNCH-INCOMING-COOKIES"><quote>+crunch-incoming-cookies</quote></link>,
8904 <link linkend="SESSION-COOKIES-ONLY"><quote>+session-cookies-only</quote></link>,
8905 and <link linkend="DOWNGRADE-HTTP-VERSION"><quote>+downgrade-http-version</quote></link>
8911 If any <link linkend="FILTER"><quote>+filter</quote></link> action
8913 linkend="DEANIMATE-GIFS"><quote>+deanimate-gifs</quote></link>
8914 action applies (and the document type fits the action), the rest of the page is
8915 read into memory (up to a configurable limit). Then the filter rules (from
8916 <filename>default.filter</filename> and any other filter files) are
8917 processed against the buffered content. Filters are applied in the order
8918 they are specified in one of the filter files. Animated GIFs, if present,
8919 are reduced to either the first or last frame, depending on the action
8920 setting.The entire page, which is now filtered, is then sent by
8921 <application>Privoxy</application> back to your browser.
8924 If neither a <link linkend="FILTER"><quote>+filter</quote></link> action
8926 linkend="DEANIMATE-GIFS"><quote>+deanimate-gifs</quote></link>
8927 matches, then <application>Privoxy</application> passes the raw data through
8928 to the client browser as it becomes available.
8933 As the browser receives the now (possibly filtered) page content, it
8934 reads and then requests any URLs that may be embedded within the page
8935 source, e.g. ad images, stylesheets, JavaScript, other HTML documents (e.g.
8936 frames), sounds, etc. For each of these objects, the browser issues a
8937 separate request (this is easily viewable in <application>Privoxy's</application>
8938 logs). And each such request is in turn processed just as above. Note that a
8939 complex web page will have many, many such embedded URLs. If these
8940 secondary requests are to a different server, then quite possibly a very
8941 differing set of actions is triggered.
8948 NOTE: This is somewhat of a simplistic overview of what happens with each URL
8949 request. For the sake of brevity and simplicity, we have focused on
8950 <application>Privoxy's</application> core features only.
8956 <!-- ~~~~~ New section ~~~~~ -->
8957 <sect2 id="actionsanat">
8958 <title>Troubleshooting: Anatomy of an Action</title>
8961 The way <application>Privoxy</application> applies
8962 <link linkend="ACTIONS">actions</link> and <link linkend="FILTER">filters</link>
8963 to any given URL can be complex, and not always so
8964 easy to understand what is happening. And sometimes we need to be able to
8965 <emphasis>see</emphasis> just what <application>Privoxy</application> is
8966 doing. Especially, if something <application>Privoxy</application> is doing
8967 is causing us a problem inadvertently. It can be a little daunting to look at
8968 the actions and filters files themselves, since they tend to be filled with
8969 <link linkend="regex">regular expressions</link> whose consequences are not
8974 One quick test to see if <application>Privoxy</application> is causing a problem
8975 or not, is to disable it temporarily. This should be the first troubleshooting
8976 step. See <link linkend="bookmarklets">the Bookmarklets</link> section on a quick
8977 and easy way to do this (be sure to flush caches afterward!). Looking at the
8978 logs is a good idea too. (Note that both the toggle feature and logging are
8979 enabled via <filename>config</filename> file settings, and may need to be
8980 turned <quote>on</quote>.)
8983 Another easy troubleshooting step to try is if you have done any
8984 customization of your installation, revert back to the installed
8985 defaults and see if that helps. There are times the developers get complaints
8986 about one thing or another, and the problem is more related to a customized
8987 configuration issue.
8991 <application>Privoxy</application> also provides the
8992 <ulink url="http://config.privoxy.org/show-url-info">http://config.privoxy.org/show-url-info</ulink>
8993 page that can show us very specifically how <application>actions</application>
8994 are being applied to any given URL. This is a big help for troubleshooting.
8998 First, enter one URL (or partial URL) at the prompt, and then
8999 <application>Privoxy</application> will tell us
9000 how the current configuration will handle it. This will not
9001 help with filtering effects (i.e. the <link
9002 linkend="FILTER"><quote>+filter</quote></link> action) from
9003 one of the filter files since this is handled very
9004 differently and not so easy to trap! It also will not tell you about any other
9005 URLs that may be embedded within the URL you are testing. For instance, images
9006 such as ads are expressed as URLs within the raw page source of HTML pages. So
9007 you will only get info for the actual URL that is pasted into the prompt area
9008 -- not any sub-URLs. If you want to know about embedded URLs like ads, you
9009 will have to dig those out of the HTML source. Use your browser's <quote>View
9010 Page Source</quote> option for this. Or right click on the ad, and grab the
9015 Let's try an example, <ulink url="http://google.com">google.com</ulink>,
9016 and look at it one section at a time in a sample configuration (your real
9017 configuration may vary):
9022 Matches for http://www.google.com:
9024 In file: default.action <guibutton>[ View ]</guibutton> <guibutton>[ Edit ]</guibutton>
9026 {+change-x-forwarded-for{block}
9027 +deanimate-gifs {last}
9028 +fast-redirects {check-decoded-url}
9029 +filter {refresh-tags}
9030 +filter {img-reorder}
9031 +filter {banners-by-size}
9033 +filter {jumping-windows}
9034 +filter {ie-exploits}
9035 +hide-from-header {block}
9036 +hide-referrer {forge}
9037 +session-cookies-only
9038 +set-image-blocker {pattern}
9041 { -session-cookies-only }
9047 In file: user.action <guibutton>[ View ]</guibutton> <guibutton>[ Edit ]</guibutton>
9048 (no matches in this file)
9053 This is telling us how we have defined our
9054 <link linkend="ACTIONS"><quote>actions</quote></link>, and
9055 which ones match for our test case, <quote>google.com</quote>.
9056 Displayed is all the actions that are available to us. Remember,
9057 the <literal>+</literal> sign denotes <quote>on</quote>. <literal>-</literal>
9058 denotes <quote>off</quote>. So some are <quote>on</quote> here, but many
9059 are <quote>off</quote>. Each example we try may provide a slightly different
9060 end result, depending on our configuration directives.
9064 is for our <filename>default.action</filename> file. The large, multi-line
9065 listing, is how the actions are set to match for all URLs, i.e. our default
9066 settings. If you look at your <quote>actions</quote> file, this would be the
9067 section just below the <quote>aliases</quote> section near the top. This
9068 will apply to all URLs as signified by the single forward slash at the end
9069 of the listing -- <quote> / </quote>.
9073 But we have defined additional actions that would be exceptions to these general
9074 rules, and then we list specific URLs (or patterns) that these exceptions
9075 would apply to. Last match wins. Just below this then are two explicit
9076 matches for <quote>.google.com</quote>. The first is negating our previous
9077 cookie setting, which was for <link
9078 linkend="SESSION-COOKIES-ONLY"><quote>+session-cookies-only</quote></link>
9079 (i.e. not persistent). So we will allow persistent cookies for google, at
9080 least that is how it is in this example. The second turns
9081 <emphasis>off</emphasis> any <link
9082 linkend="FAST-REDIRECTS"><quote>+fast-redirects</quote></link>
9083 action, allowing this to take place unmolested. Note that there is a leading
9084 dot here -- <quote>.google.com</quote>. This will match any hosts and
9085 sub-domains, in the google.com domain also, such as
9086 <quote>www.google.com</quote> or <quote>mail.google.com</quote>. But it would not
9087 match <quote>www.google.de</quote>! So, apparently, we have these two actions
9088 defined as exceptions to the general rules at the top somewhere in the lower
9089 part of our <filename>default.action</filename> file, and
9090 <quote>google.com</quote> is referenced somewhere in these latter sections.
9094 Then, for our <filename>user.action</filename> file, we again have no hits.
9095 So there is nothing google-specific that we might have added to our own, local
9096 configuration. If there was, those actions would over-rule any actions from
9097 previously processed files, such as <filename>default.action</filename>.
9098 <filename>user.action</filename> typically has the last word. This is the
9099 best place to put hard and fast exceptions,
9103 And finally we pull it all together in the bottom section and summarize how
9104 <application>Privoxy</application> is applying all its <quote>actions</quote>
9105 to <quote>google.com</quote>:
9116 +change-x-forwarded-for{block}
9117 -client-header-filter{hide-tor-exit-notation}
9118 -content-type-overwrite
9119 -crunch-client-header
9120 -crunch-if-none-match
9121 -crunch-incoming-cookies
9122 -crunch-outgoing-cookies
9123 -crunch-server-header
9124 +deanimate-gifs {last}
9125 -downgrade-http-version
9128 -filter {content-cookies}
9129 -filter {all-popups}
9130 -filter {banners-by-link}
9131 -filter {tiny-textforms}
9132 -filter {frameset-borders}
9133 -filter {demoronizer}
9134 -filter {shockwave-flash}
9135 -filter {quicktime-kioskmode}
9137 -filter {crude-parental}
9138 -filter {site-specifics}
9139 -filter {js-annoyances}
9140 -filter {html-annoyances}
9141 +filter {refresh-tags}
9142 -filter {unsolicited-popups}
9143 +filter {img-reorder}
9144 +filter {banners-by-size}
9146 +filter {jumping-windows}
9147 +filter {ie-exploits}
9154 -handle-as-empty-document
9156 -hide-accept-language
9157 -hide-content-disposition
9158 +hide-from-header {block}
9159 -hide-if-modified-since
9160 +hide-referrer {forge}
9163 -overwrite-last-modified
9164 -prevent-compression
9166 -server-header-filter{xml-to-html}
9167 -server-header-filter{html-to-xml}
9168 -session-cookies-only
9169 +set-image-blocker {pattern} </screen>
9173 Notice the only difference here to the previous listing, is to
9174 <quote>fast-redirects</quote> and <quote>session-cookies-only</quote>,
9175 which are activated specifically for this site in our configuration,
9176 and thus show in the <quote>Final Results</quote>.
9180 Now another example, <quote>ad.doubleclick.net</quote>:
9186 { +block{Domains starts with "ad"} }
9189 { +block{Domain contains "ad"} }
9192 { +block{Doubleclick banner server} +handle-as-image }
9193 .[a-vx-z]*.doubleclick.net
9198 We'll just show the interesting part here - the explicit matches. It is
9199 matched three different times. Two <quote>+block{}</quote> sections,
9200 and a <quote>+block{} +handle-as-image</quote>,
9201 which is the expanded form of one of our aliases that had been defined as:
9202 <quote>+block-as-image</quote>. (<link
9203 linkend="ALIASES"><quote>Aliases</quote></link> are defined in
9204 the first section of the actions file and typically used to combine more
9209 Any one of these would have done the trick and blocked this as an unwanted
9210 image. This is unnecessarily redundant since the last case effectively
9211 would also cover the first. No point in taking chances with these guys
9212 though ;-) Note that if you want an ad or obnoxious
9213 URL to be invisible, it should be defined as <quote>ad.doubleclick.net</quote>
9214 is done here -- as both a <link
9215 linkend="BLOCK"><quote>+block{}</quote></link>
9216 <emphasis>and</emphasis> an
9217 <link linkend="HANDLE-AS-IMAGE"><quote>+handle-as-image</quote></link>.
9218 The custom alias <quote><literal>+block-as-image</literal></quote> just
9219 simplifies the process and make it more readable.
9223 One last example. Let's try <quote>http://www.example.net/adsl/HOWTO/</quote>.
9224 This one is giving us problems. We are getting a blank page. Hmmm ...
9230 Matches for http://www.example.net/adsl/HOWTO/:
9232 In file: default.action <guibutton>[ View ]</guibutton> <guibutton>[ Edit ]</guibutton>
9236 +change-x-forwarded-for{block}
9237 -client-header-filter{hide-tor-exit-notation}
9238 -content-type-overwrite
9239 -crunch-client-header
9240 -crunch-if-none-match
9241 -crunch-incoming-cookies
9242 -crunch-outgoing-cookies
9243 -crunch-server-header
9245 -downgrade-http-version
9246 +fast-redirects {check-decoded-url}
9248 -filter {content-cookies}
9249 -filter {all-popups}
9250 -filter {banners-by-link}
9251 -filter {tiny-textforms}
9252 -filter {frameset-borders}
9253 -filter {demoronizer}
9254 -filter {shockwave-flash}
9255 -filter {quicktime-kioskmode}
9257 -filter {crude-parental}
9258 -filter {site-specifics}
9259 -filter {js-annoyances}
9260 -filter {html-annoyances}
9261 +filter {refresh-tags}
9262 -filter {unsolicited-popups}
9263 +filter {img-reorder}
9264 +filter {banners-by-size}
9266 +filter {jumping-windows}
9267 +filter {ie-exploits}
9274 -handle-as-empty-document
9276 -hide-accept-language
9277 -hide-content-disposition
9278 +hide-from-header{block}
9279 +hide-referer{forge}
9281 -overwrite-last-modified
9282 +prevent-compression
9284 -server-header-filter{xml-to-html}
9285 -server-header-filter{html-to-xml}
9286 +session-cookies-only
9287 +set-image-blocker{blank} }
9290 { +block{Path contains "ads".} +handle-as-image }
9296 Ooops, the <quote>/adsl/</quote> is matching <quote>/ads</quote> in our
9297 configuration! But we did not want this at all! Now we see why we get the
9298 blank page. It is actually triggering two different actions here, and
9299 the effects are aggregated so that the URL is blocked, and &my-app; is told
9300 to treat the block as if it were an image. But this is, of course, all wrong.
9301 We could now add a new action below this (or better in our own
9302 <filename>user.action</filename> file) that explicitly
9303 <emphasis>un</emphasis> blocks (
9304 <link linkend="BLOCK"><quote>{-block}</quote></link>) paths with
9305 <quote>adsl</quote> in them (remember, last match in the configuration
9306 wins). There are various ways to handle such exceptions. Example:
9318 Now the page displays ;-)
9319 Remember to flush your browser's caches when making these kinds of changes to
9320 your configuration to insure that you get a freshly delivered page! Or, try
9321 using <literal>Shift+Reload</literal>.
9325 But now what about a situation where we get no explicit matches like
9332 { +block{Path starts with "ads".} +handle-as-image }
9338 That actually was very helpful and pointed us quickly to where the problem
9339 was. If you don't get this kind of match, then it means one of the default
9340 rules in the first section of <filename>default.action</filename> is causing
9341 the problem. This would require some guesswork, and maybe a little trial and
9342 error to isolate the offending rule. One likely cause would be one of the
9343 <link linkend="FILTER"><quote>+filter</quote></link> actions.
9344 These tend to be harder to troubleshoot.
9345 Try adding the URL for the site to one of aliases that turn off
9346 <link linkend="FILTER"><quote>+filter</quote></link>:
9354 .worldpay.com # for quietpc.com
9362 <quote><literal>{ shop }</literal></quote> is an <quote>alias</quote> that expands to
9363 <quote><literal>{ -filter -session-cookies-only }</literal></quote>.
9364 Or you could do your own exception to negate filtering:
9372 # Disable ALL filter actions for sites in this section
9380 This would turn off all filtering for these sites. This is best
9381 put in <filename>user.action</filename>, for local site
9382 exceptions. Note that when a simple domain pattern is used by itself (without
9383 the subsequent path portion), all sub-pages within that domain are included
9384 automatically in the scope of the action.
9388 Images that are inexplicably being blocked, may well be hitting the
9389 <link linkend="FILTER-BANNERS-BY-SIZE"><quote>+filter{banners-by-size}</quote></link>
9391 that images of certain sizes are ad banners (works well
9392 <emphasis>most of the time</emphasis> since these tend to be standardized).
9396 <quote><literal>{ fragile }</literal></quote> is an alias that disables most
9397 actions that are the most likely to cause trouble. This can be used as a
9398 last resort for problem sites.
9404 # Handle with care: easy to break
9406 mybank.example.com</screen>
9411 <emphasis>Remember to flush caches!</emphasis> Note that the
9412 <literal>mail.google</literal> reference lacks the TLD portion (e.g.
9413 <quote>.com</quote>). This will effectively match any TLD with
9414 <literal>google</literal> in it, such as <literal>mail.google.de.</literal>,
9418 If this still does not work, you will have to go through the remaining
9419 actions one by one to find which one(s) is causing the problem.
9428 This program is free software; you can redistribute it
9429 and/or modify it under the terms of the GNU General
9430 Public License as published by the Free Software
9431 Foundation; either version 2 of the License, or (at
9432 your option) any later version.
9434 This program is distributed in the hope that it will
9435 be useful, but WITHOUT ANY WARRANTY; without even the
9436 implied warranty of MERCHANTABILITY or FITNESS FOR A
9437 PARTICULAR PURPOSE. See the GNU General Public
9438 License for more details.
9440 The GNU General Public License should be included with
9441 this file. If not, you can view it at
9442 http://www.gnu.org/copyleft/gpl.html
9443 or write to the Free Software Foundation, Inc.,
9444 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301,