1 <!DOCTYPE article PUBLIC "-//OASIS//DTD DocBook V3.1//EN" [
2 <!entity % dummy "IGNORE">
3 <!entity supported SYSTEM "supported.sgml">
4 <!entity newfeatures SYSTEM "newfeatures.sgml">
5 <!entity p-intro SYSTEM "privoxy.sgml">
6 <!entity seealso SYSTEM "seealso.sgml">
7 <!entity buildsource SYSTEM "buildsource.sgml">
8 <!entity contacting SYSTEM "contacting.sgml">
9 <!entity history SYSTEM "history.sgml">
10 <!entity copyright SYSTEM "copyright.sgml">
11 <!entity license SYSTEM "license.sgml">
12 <!entity p-authors SYSTEM "p-authors.sgml">
13 <!entity config SYSTEM "p-config.sgml">
14 <!entity changelog SYSTEM "changelog.sgml">
15 <!entity p-version "3.0.20">
16 <!entity p-status "beta">
17 <!entity % p-authors-formal "INCLUDE"> <!-- include additional text, etc -->
18 <!entity % p-not-stable "INCLUDE">
19 <!entity % p-stable "IGNORE">
20 <!entity % p-text "IGNORE"> <!-- define we are not a text only doc -->
21 <!entity % p-doc "INCLUDE"> <!-- and we are a formal doc -->
22 <!entity % p-readme "IGNORE">
23 <!entity % user-man "IGNORE">
24 <!entity % config-file "IGNORE">
25 <!entity % p-supp-userman "IGNORE"> <!-- Omit some from supported.sgml -->
26 <!entity my-copy "©"> <!-- kludge for docbook2man -->
27 <!entity % draft "IGNORE"> <!-- WIP stuff -->
28 <!entity % seealso-extra "INCLUDE"> <!-- extra stuff from seealso.sgml -->
29 <!entity my-app "<application>Privoxy</application>">
32 File : $Source: /cvsroot/ijbswa/current/doc/source/user-manual.sgml,v $
35 This file belongs into
36 ijbswa.sourceforge.net:/home/groups/i/ij/ijbswa/htdocs/
38 $Id: user-manual.sgml,v 2.164 2013/01/18 18:45:21 fabiankeil Exp $
40 Copyright (C) 2001-2013 Privoxy Developers http://www.privoxy.org/
43 ========================================================================
44 NOTE: Please read developer-manual/documentation.html before touching
45 anything in this, or other Privoxy documentation.
46 ========================================================================
53 <title>Privoxy &p-version; User Manual</title>
57 <!-- Completely the wrong markup, but very little is allowed -->
58 <!-- in this part of an article. FIXME -->
59 <link linkend="copyright">Copyright</link> &my-copy; 2001-2013 by
60 <ulink url="http://www.privoxy.org/">Privoxy Developers</ulink>
64 <pubdate>$Id: user-manual.sgml,v 2.164 2013/01/18 18:45:21 fabiankeil Exp $</pubdate>
68 Note: the following should generate a separate page, and a live link to it,
69 all nicely done. But it doesn't for some mysterious reason. Please leave
70 commented unless it can be fixed proper. For the time being, the
71 copyright/license declarations will be in their own sgml.
84 This is here to keep vim syntax file from breaking :/
85 If I knew enough to fix it, I would.
86 PLEASE DO NOT REMOVE! HB: hal@foobox.net
92 The <citetitle>Privoxy User Manual</citetitle> gives users information on how to
93 install, configure and use <ulink
94 url="http://www.privoxy.org/">Privoxy</ulink>.
97 <!-- Include privoxy.sgml boilerplate: -->
99 <!-- end privoxy.sgml -->
102 You can find the latest version of the <citetitle>Privoxy User Manual</citetitle> at <ulink
103 url="http://www.privoxy.org/user-manual/">http://www.privoxy.org/user-manual/</ulink>.
104 Please see the <link linkend="contact">Contact section</link> on how to
105 contact the developers.
109 <!-- Feel free to send a note to the developers at <email>ijbswa-developers@lists.sourceforge.net</email>. -->
115 <!-- ~~~~~ New section ~~~~~ -->
116 <sect1 label="1" id="introduction"><title>Introduction</title>
118 This documentation is included with the current &p-status; version of
119 <application>Privoxy</application>, v.&p-version;<![%p-not-stable;[,
120 and is mostly complete at this point. The most up to date reference for the
121 time being is still the comments in the source files and in the individual
122 configuration files. Development of a new version is currently nearing
123 completion, and includes significant changes and enhancements over
127 <!-- include only in non-stable versions -->
130 Since this is a &p-status; version, not all new features are well tested. This
131 documentation may be slightly out of sync as a result (especially with
132 CVS sources). And there <emphasis>may be</emphasis> bugs, though hopefully
137 <!-- ~~~~~ New section ~~~~~ -->
138 <sect2 id="features"><title>Features</title>
140 In addition to the core
141 features of ad blocking and
142 <ulink url="http://en.wikipedia.org/wiki/Browser_cookie">cookie</ulink> management,
143 <application>Privoxy</application> provides many supplemental
144 features<![%p-not-stable;[, some of them currently under development]]>,
145 that give the end-user more control, more privacy and more freedom:
147 <!-- Include newfeatures.sgml boilerplate here: -->
149 <!-- end boilerplate -->
154 <!-- ~ End section ~ -->
157 <!-- ~~~~~ New section ~~~~~ -->
158 <sect1 id="installation"><title>Installation</title>
161 <application>Privoxy</application> is available both in convenient pre-compiled
162 packages for a wide range of operating systems, and as raw source code.
163 For most users, we recommend using the packages, which can be downloaded from our
164 <ulink url="http://sourceforge.net/projects/ijbswa/">Privoxy Project
170 On some platforms, the installer may remove previously installed versions, if
171 found. (See below for your platform). In any case <emphasis>be sure to backup
172 your old configuration if it is valuable to you.</emphasis> See the <link
173 linkend="upgradersnote">note to upgraders</link> section below.
176 <!-- ~~~~~ New section ~~~~~ -->
177 <sect2 id="installation-packages"><title>Binary Packages</title>
179 How to install the binary packages depends on your operating system:
182 <!-- XXX: The installation sections should be sorted -->
184 <!-- ~~~~~ New section ~~~~~ -->
185 <sect3 id="installation-deb"><title>Debian and Ubuntu</title>
187 DEBs can be installed with <literal>apt-get install privoxy</literal>,
188 and will use <filename>/etc/privoxy</filename> for the location of
193 <!-- ~~~~~ New section ~~~~~ -->
194 <sect3 id="installation-pack-win"><title>Windows</title>
197 Just double-click the installer, which will guide you through
198 the installation process. You will find the configuration files
199 in the same directory as you installed <application>Privoxy</application> in.
202 Version 3.0.5 beta introduced full <application>Windows</application> service
203 functionality. On Windows only, the <application>Privoxy</application>
204 program has two new command line arguments to install and uninstall
205 <application>Privoxy</application> as a <emphasis>service</emphasis>.
209 <term>Arguments:</term>
212 <replaceable class="parameter">--install</replaceable>[:<replaceable class="parameter">service_name</replaceable>]
215 <replaceable class="parameter">--uninstall</replaceable>[:<replaceable class="parameter">service_name</replaceable>]
221 After invoking <application>Privoxy</application> with
222 <command>--install</command>, you will need to bring up the
223 <application>Windows</application> service console to assign the user you
224 want <application>Privoxy</application> to run under, and whether or not you
225 want it to run whenever the system starts. You can start the
226 <application>Windows</application> services console with the following
227 command: <command>services.msc</command>. If you do not take the manual step
228 of modifying <application>Privoxy's</application> service settings, it will
229 not start. Note too that you will need to give Privoxy a user account that
230 actually exists, or it will not be permitted to
231 write to its log and configuration files.
236 <!-- ~~~~~ New section ~~~~~ -->
237 <sect3 id="installation-os2"><title>OS/2</title>
240 First, make sure that no previous installations of
241 <application>Junkbuster</application> and / or
242 <application>Privoxy</application> are left on your
243 system. Check that no <application>Junkbuster</application>
244 or <application>Privoxy</application> objects are in
250 Then, just double-click the WarpIN self-installing archive, which will
251 guide you through the installation process. A shadow of the
252 <application>Privoxy</application> executable will be placed in your
253 startup folder so it will start automatically whenever OS/2 starts.
257 The directory you choose to install <application>Privoxy</application>
258 into will contain all of the configuration files.
262 <!-- ~~~~~ New section ~~~~~ -->
263 <sect3 id="installation-mac"><title>Mac OS X</title>
265 Installation instructions for the OS X platform depend upon whether
266 you downloaded a ready-built installation package (.pkg or .mpkg) or have
267 downloaded the source code.
270 <sect3 renderas="sect4" id="OS-X-install-from-package">
271 <title>Installation from ready-built package</title>
273 The downloaded file will either be a .pkg (for OS X 10.5 upwards) or a bzipped
274 .mpkg file (for OS X 10.4). The former can be double-clicked as is and the
275 installation will start; double-clicking the latter will unzip the .mpkg file
276 which can then be double-clicked to commence the installation.
279 The privoxy service will automatically start after a successful installation
280 (and thereafter every time your computer starts up) however you will need to
281 configure your web browser(s) to use it. To do so, configure them to use a
282 proxy for HTTP and HTTPS at the address 127.0.0.1:8118.
285 To prevent the privoxy service from automatically starting when your computer
286 starts up, remove or rename the file <literal>/Library/LaunchDaemons/org.ijbswa.privoxy.plist</literal>
287 (on OS X 10.5 and higher) or the folder named
288 <literal>/Library/StartupItems/Privoxy</literal> (on OS X 10.4 'Tiger').
291 To manually start or stop the privoxy service, use the scripts startPrivoxy.sh
292 and stopPrivoxy.sh supplied in /Applications/Privoxy. They must be run from an
293 administrator account, using sudo.
296 To uninstall, run /Applications/Privoxy/uninstall.command as sudo from an
297 administrator account.
300 <sect3 renderas="sect4" id="OS-X-install-from-source">
301 <title>Installation from source</title>
303 To build and install the Privoxy source code on OS X you will need to obtain
304 the macsetup module from the Privoxy Sourceforge CVS repository (refer to
305 Sourceforge help for details of how to set up a CVS client to have read-only
306 access to the repository). This module contains scripts that leverage the usual
307 open-source tools (available as part of Apple's free of charge Xcode
308 distribution or via the usual open-source software package managers for OS X
309 (MacPorts, Homebrew, Fink etc.) to build and then install the privoxy binary
310 and associated files. The macsetup module's README file contains complete
311 instructions for its use.
314 The privoxy service will automatically start after a successful installation
315 (and thereafter every time your computer starts up) however you will need to
316 configure your web browser(s) to use it. To do so, configure them to use a
317 proxy for HTTP and HTTPS at the address 127.0.0.1:8118.
320 To prevent the privoxy service from automatically starting when your computer
321 starts up, remove or rename the file <literal>/Library/LaunchDaemons/org.ijbswa.privoxy.plist</literal>
322 (on OS X 10.5 and higher) or the folder named
323 <literal>/Library/StartupItems/Privoxy</literal> (on OS X 10.4 'Tiger').
326 To manually start or stop the privoxy service, use the Privoxy Utility
327 for Mac OS X (also part of the macsetup module). This application can start
328 and stop the privoxy service and display its log and configuration files.
331 To uninstall, run the macsetup module's uninstall.sh as sudo from an
332 administrator account.
336 <!-- ~~~~~ New section ~~~~~ -->
337 <sect3 id="installation-tbz"><title>FreeBSD</title>
340 Privoxy is part of FreeBSD's Ports Collection, you can build and install
341 it with <literal>cd /usr/ports/www/privoxy; make install clean</literal>.
344 If you don't use the ports, you can fetch and install
345 the package with <literal>pkg_add -r privoxy</literal>.
348 The port skeleton and the package can also be downloaded from the
349 <ulink url="https://sourceforge.net/project/showfiles.php?group_id=11118">File Release
350 Page</ulink>, but there's no reason to use them unless you're interested in the
351 beta releases which are only available there.
357 <!-- ~~~~~ New section ~~~~~ -->
358 <sect2 id="installation-source"><title>Building from Source</title>
361 The most convenient way to obtain the <application>Privoxy</application> sources
362 is to download the source tarball from our
363 <ulink url="http://sourceforge.net/project/showfiles.php?group_id=11118&package_id=10571">project download
368 If you like to live on the bleeding edge and are not afraid of using
369 possibly unstable development versions, you can check out the up-to-the-minute
370 version directly from <ulink url="http://sourceforge.net/cvs/?group_id=11118">the
371 CVS repository</ulink>.
373 deprecated...out of business.
374 or simply download <ulink
375 url="http://cvs.sourceforge.net/cvstarballs/ijbswa-cvsroot.tar.bz2">the nightly CVS
380 <!-- include buildsource.sgml boilerplate: -->
382 <!-- end boilerplate -->
385 <!-- ~~~~~ New section ~~~~~ -->
386 <sect2 id="installation-keepupdated"><title>Keeping your Installation Up-to-Date</title>
389 If you wish to receive an email notification whenever we release updates of
390 <application>Privoxy</application> or the actions file, <ulink
391 url="http://lists.sourceforge.net/lists/listinfo/ijbswa-announce/">subscribe
392 to our announce mailing list</ulink>, ijbswa-announce@lists.sourceforge.net.
396 In order not to lose your personal changes and adjustments when updating
397 to the latest <literal>default.action</literal> file we <emphasis>strongly
398 recommend</emphasis> that you use <literal>user.action</literal> and
399 <literal>user.filter</literal> for your local
400 customizations of <application>Privoxy</application>. See the <link
401 linkend="actions-file">Chapter on actions files</link> for details.
409 <!-- ~ End section ~ -->
411 <!-- ~~~~~ New section ~~~~~ -->
412 <sect1 id="whatsnew">
413 <title>What's New in this Release</title>
417 <!-- ~~~~~ New section ~~~~~ -->
419 <sect2 id="upgradersnote">
420 <title>Note to Upgraders</title>
423 A quick list of things to be aware of before upgrading from earlier
424 versions of <application>Privoxy</application>:
432 The recommended way to upgrade &my-app; is to backup your old
433 configuration files, install the new ones, verify that &my-app;
434 is working correctly and finally merge back your changes using
435 <application>diff</application> and maybe <application>patch</application>.
438 There are a number of new features in each &my-app; release and
439 most of them have to be explicitly enabled in the configuration
440 files. Old configuration files obviously don't do that and due
441 to syntax changes using old configuration files with a new
442 &my-app; isn't always possible anyway.
447 Note that some installers remove earlier versions completely,
448 including configuration files, therefore you should really save
449 any important configuration files!
454 On the other hand, other installers don't overwrite existing configuration
455 files, thinking you will want to do that yourself.
460 <filename>standard.action</filename> has been merged into
461 the <filename>default.action</filename> file.
466 In the default configuration only fatal errors are logged now.
467 You can change that in the <link linkend="DEBUG">debug section</link>
468 of the configuration file. You may also want to enable more verbose
469 logging until you verified that the new &my-app; version is working
476 Three other config file settings are now off by default:
477 <link linkend="enable-remote-toggle">enable-remote-toggle</link>,
478 <link linkend="enable-remote-http-toggle">enable-remote-http-toggle</link>,
479 and <link linkend="enable-edit-actions">enable-edit-actions</link>.
480 If you use or want these, you will need to explicitly enable them, and
481 be aware of the security issues involved.
488 What constitutes a <quote>default</quote> configuration has changed,
489 and you may want to review which actions are <quote>on</quote> by
490 default. This is primarily a matter of emphasis, but some features
491 you may have been used to, may now be <quote>off</quote> by default.
492 There are also a number of new actions and filters you may want to
493 consider, most of which are not fully incorporated into the default
494 settings as yet (see above).
501 The default actions setting is now <literal>Cautious</literal>. Previous
502 releases had a default setting of <literal>Medium</literal>. Experienced
503 users may want to adjust this, as it is fairly conservative by &my-app;
504 standards and past practices. See <ulink
505 url="http://config.privoxy.org/edit-actions-list?f=default">
506 http://config.privoxy.org/edit-actions-list?f=default</ulink>. New users
507 should try the default settings for a while before turning up the volume.
513 The default setting has filtering turned <emphasis>off</emphasis>, which
514 subsequently means that compression is <emphasis>on</emphasis>. Remember
515 that filtering does not work on compressed pages, so if you use, or want to
516 use, filtering, you will need to force compression off. Example:
520 { +<link linkend="filter">filter</link>{google} +<link linkend="prevent-compression">prevent-compression</link> }
524 Or if you use a number of filters, or filter many sites, you may just want
525 to turn off compression for all sites in
526 <filename>default.action</filename> (or
527 <filename>user.action</filename>).
534 Also, <link linkend="SESSION-COOKIES-ONLY">session-cookies-only</link> is
535 off by default now. If you've liked this feature in the past, you may want
536 to turn it back on in <filename>user.action</filename> now.
543 Some installers may not automatically start
544 <application>Privoxy</application> after installation.
555 <!-- ~~~~~ New section ~~~~~ -->
556 <sect1 id="quickstart"><title>Quickstart to Using Privoxy</title>
562 Install <application>Privoxy</application>. See the <link
563 linkend="installation">Installation Section</link> below for platform specific
570 Advanced users and those who want to offer <application>Privoxy</application>
571 service to more than just their local machine should check the <link
572 linkend="config">main config file</link>, especially the <link
573 linkend="access-control">security-relevant</link> options. These are
580 Start <application>Privoxy</application>, if the installation program has
581 not done this already (may vary according to platform). See the section
582 <link linkend="startup">Starting <application>Privoxy</application></link>.
588 Set your browser to use <application>Privoxy</application> as HTTP and
589 HTTPS (SSL) <ulink url="http://en.wikipedia.org/wiki/Proxy_server">proxy</ulink>
590 by setting the proxy configuration for address of
591 <literal>127.0.0.1</literal> and port <literal>8118</literal>.
592 <emphasis>DO NOT</emphasis> activate proxying for <literal>FTP</literal> or
593 any protocols besides HTTP and HTTPS (SSL) unless you intend to prevent your
594 browser from using these protocols.
600 Flush your browser's disk and memory caches, to remove any cached ad images.
601 If using <application>Privoxy</application> to manage
602 <ulink url="http://en.wikipedia.org/wiki/Browser_cookie">cookies</ulink>,
603 you should remove any currently stored cookies too.
609 A default installation should provide a reasonable starting point for
610 most. There will undoubtedly be occasions where you will want to adjust the
611 configuration, but that can be dealt with as the need arises. Little
612 to no initial configuration is required in most cases, you may want
614 <ulink url="config.html#ENABLE-EDIT-ACTIONS">web-based action editor</ulink> though.
615 Be sure to read the warnings first.
618 See the <link linkend="configuration">Configuration section</link> for more
619 configuration options, and how to customize your installation.
620 You might also want to look at the <link
621 linkend="quickstart-ad-blocking">next section</link> for a quick
622 introduction to how <application>Privoxy</application> blocks ads and
629 If you experience ads that slip through, innocent images that are
630 blocked, or otherwise feel the need to fine-tune
631 <application>Privoxy's</application> behavior, take a look at the <link
632 linkend="actions-file">actions files</link>. As a quick start, you might
633 find the <link linkend="act-examples">richly commented examples</link>
634 helpful. You can also view and edit the actions files through the <ulink
635 url="http://config.privoxy.org">web-based user interface</ulink>. The
636 Appendix <quote><link linkend="actionsanat">Troubleshooting: Anatomy of an
637 Action</link></quote> has hints on how to understand and debug actions that
638 <quote>misbehave</quote>.
643 Did anyone test these lately?
647 For easy access to &my-app;'s most important controls, drag the provided
648 <link linkend="bookmarklets">Bookmarklets</link> into your browser's
656 Please see the section <link linkend="contact">Contacting the
657 Developers</link> on how to report bugs, problems with websites or to get
664 Now enjoy surfing with enhanced control, comfort and privacy!
672 <!-- ~~~~~ New section ~~~~~ -->
674 <sect2 id="quickstart-ad-blocking">
675 <title>Quickstart to Ad Blocking</title>
677 NOTE: This section is deliberately redundant for those that don't
678 want to read the whole thing (which is getting lengthy).
681 Ad blocking is but one of <application>Privoxy's</application>
682 array of features. Many of these features are for the technically minded advanced
683 user. But, ad and banner blocking is surely common ground for everybody.
686 This section will provide a quick summary of ad blocking so
687 you can get up to speed quickly without having to read the more extensive
688 information provided below, though this is highly recommended.
691 First a bit of a warning ... blocking ads is much like blocking SPAM: the
692 more aggressive you are about it, the more likely you are to block
693 things that were not intended. And the more likely that some things
694 may not work as intended. So there is a trade off here. If you want
695 extreme ad free browsing, be prepared to deal with more
696 <quote>problem</quote> sites, and to spend more time adjusting the
697 configuration to solve these unintended consequences. In short, there is
698 not an easy way to eliminate <emphasis>all</emphasis> ads. Either take
699 the easy way and settle for <emphasis>most</emphasis> ads blocked with the
700 default configuration, or jump in and tweak it for your personal surfing
701 habits and preferences.
704 Secondly, a brief explanation of <application>Privoxy's </application>
705 <quote>actions</quote>. <quote>Actions</quote> in this context, are
706 the directives we use to tell <application>Privoxy</application> to perform
707 some task relating to HTTP transactions (i.e. web browsing). We tell
708 <application>Privoxy</application> to take some <quote>action</quote>. Each
709 action has a unique name and function. While there are many potential
710 <application>actions</application> in <application>Privoxy's</application>
711 arsenal, only a few are used for ad blocking. <link
712 linkend="actions">Actions</link>, and <link linkend="actions-file">action
713 configuration files</link>, are explained in depth below.
716 Actions are specified in <application>Privoxy's</application> configuration,
717 followed by one or more URLs to which the action should apply. URLs
718 can actually be URL type <link linkend="af-patterns">patterns</link> that use
719 wildcards so they can apply potentially to a range of similar URLs. The
720 actions, together with the URL patterns are called a section.
723 When you connect to a website, the full URL will either match one or more
724 of the sections as defined in <application>Privoxy's</application> configuration,
725 or not. If so, then <application>Privoxy</application> will perform the
726 respective actions. If not, then nothing special happens. Furthermore, web
727 pages may contain embedded, secondary URLs that your web browser will
728 use to load additional components of the page, as it parses the
729 original page's HTML content. An ad image for instance, is just an URL
730 embedded in the page somewhere. The image itself may be on the same server,
731 or a server somewhere else on the Internet. Complex web pages will have many
732 such embedded URLs. &my-app; can deal with each URL individually, so, for
733 instance, the main page text is not touched, but images from such-and-such
738 The most important actions for basic ad blocking are: <literal><link
739 linkend="block">block</link></literal>, <literal><link
740 linkend="handle-as-image">handle-as-image</link></literal>,
742 linkend="handle-as-empty-document">handle-as-empty-document</link></literal>,and
743 <literal><link linkend="set-image-blocker">set-image-blocker</link></literal>:
751 <literal><link linkend="block">block</link></literal> - this is perhaps
752 the single most used action, and is particularly important for ad blocking.
753 This action stops any contact between your browser and any URL patterns
754 that match this action's configuration. It can be used for blocking ads,
755 but also anything that is determined to be unwanted. By itself, it simply
756 stops any communication with the remote server and sends
757 <application>Privoxy</application>'s own built-in BLOCKED page instead to
758 let you now what has happened (with some exceptions, see below).
764 <literal><link linkend="handle-as-image">handle-as-image</link></literal> -
765 tells <application>Privoxy</application> to treat this URL as an image.
766 <application>Privoxy</application>'s default configuration already does this
767 for all common image types (e.g. GIF), but there are many situations where this
768 is not so easy to determine. So we'll force it in these cases. This is particularly
769 important for ad blocking, since only if we know that it's an image of
770 some kind, can we replace it with an image of our choosing, instead of the
771 <application>Privoxy</application> BLOCKED page (which would only result in
772 a <quote>broken image</quote> icon). There are some limitations to this
773 though. For instance, you can't just brute-force an image substitution for
774 an entire HTML page in most situations.
780 <literal><link linkend="handle-as-empty-document">handle-as-empty-document</link></literal> -
781 sends an empty document instead of <application>Privoxy's</application>
782 normal BLOCKED HTML page. This is useful for file types that are neither
783 HTML nor images, such as blocking JavaScript files.
790 linkend="set-image-blocker">set-image-blocker</link></literal> - tells
791 <application>Privoxy</application> what to display in place of an ad image that
792 has hit a block rule. For this to come into play, the URL must match a
793 <literal><link linkend="block">block</link></literal> action somewhere in the
794 configuration, <emphasis>and</emphasis>, it must also match an
795 <literal><link linkend="handle-as-image">handle-as-image</link></literal> action.
798 The configuration options on what to display instead of the ad are:
802 <emphasis>pattern</emphasis> - a checkerboard pattern, so that an ad
803 replacement is obvious. This is the default.
808 <emphasis>blank</emphasis> - A very small empty GIF image is displayed.
809 This is the so-called <quote>invisible</quote> configuration option.
814 <emphasis>http://<URL></emphasis> - A redirect to any image anywhere
815 of the user's choosing (advanced usage).
824 Advanced users will eventually want to explore &my-app;
825 <literal><link linkend="filter">filters</link></literal> as well. Filters
826 are very different from <literal><link
827 linkend="block">blocks</link></literal>.
828 A <quote>block</quote> blocks a site, page, or unwanted contented. Filters
829 are a way of filtering or modifying what is actually on the page. An example
830 filter usage: a text replacement of <quote>no-no</quote> for
831 <quote>nasty-word</quote>. That is a very simple example. This process can be
832 used for ad blocking, but it is more in the realm of advanced usage and has
833 some pitfalls to be wary off.
837 The quickest way to adjust any of these settings is with your browser through
838 the special <application>Privoxy</application> editor at <ulink
839 url="http://config.privoxy.org/show-status">http://config.privoxy.org/show-status</ulink>
840 (shortcut: <ulink url="http://p.p/">http://p.p/show-status</ulink>). This
841 is an internal page, and does not require Internet access.
845 Note that as of <application>Privoxy</application> 3.0.7 beta the
846 action editor is disabled by default. Check the
847 <ulink url="config.html#ENABLE-EDIT-ACTIONS">enable-edit-actions
848 section in the configuration file</ulink> to learn why and in which
849 cases it's safe to enable again.
853 If you decided to enable the action editor, select the appropriate
854 <quote>actions</quote> file, and click
855 <quote><guibutton>Edit</guibutton></quote>. It is best to put personal or
856 local preferences in <filename>user.action</filename> since this is not
857 meant to be overwritten during upgrades, and will over-ride the settings in
858 other files. Here you can insert new <quote>actions</quote>, and URLs for ad
859 blocking or other purposes, and make other adjustments to the configuration.
860 <application>Privoxy</application> will detect these changes automatically.
864 A quick and simple step by step example:
872 Right click on the ad image to be blocked, then select
873 <quote><guimenuitem>Copy Link Location</guimenuitem></quote> from the
881 url="http://config.privoxy.org/show-status">http://config.privoxy.org/show-status</ulink>
886 Find <filename>user.action</filename> in the top section, and click
887 on <quote><guibutton>Edit</guibutton></quote>:
890 <!-- image of editor and actions files selections -->
892 <figure pgwide="0" float="0"><title>Actions Files in Use</title>
895 <imagedata fileref="files-in-use.jpg" format="jpg">
898 <phrase>[ Screenshot of Actions Files in Use ]</phrase>
907 You should have a section with only
908 <literal><link linkend="block">block</link></literal> listed under
909 <quote>Actions:</quote>.
910 If not, click a <quote><guibutton>Insert new section below</guibutton></quote>
911 button, and in the new section that just appeared, click the
912 <guibutton>Edit</guibutton> button right under the word <quote>Actions:</quote>.
913 This will bring up a list of all actions. Find
914 <literal><link linkend="block">block</link></literal> near the top, and click
915 in the <quote>Enabled</quote> column, then <quote><guibutton>Submit</guibutton></quote>
921 Now, in the <literal><link linkend="block">block</link></literal> actions section,
922 click the <quote><guibutton>Add</guibutton></quote> button, and paste the URL the
923 browser got from <quote><guimenuitem>Copy Link Location</guimenuitem></quote>.
924 Remove the <literal>http://</literal> at the beginning of the URL. Then, click
925 <quote><guibutton>Submit</guibutton></quote> (or
926 <quote><guibutton>OK</guibutton></quote> if in a pop-up window).
931 Now go back to the original page, and press <keycap>SHIFT-Reload</keycap>
932 (or flush all browser caches). The image should be gone now.
940 This is a very crude and simple example. There might be good reasons to use a
941 wildcard pattern match to include potentially similar images from the same
942 site. For a more extensive explanation of <quote>patterns</quote>, and
943 the entire actions concept, see <link linkend="actions-file">the Actions
948 For advanced users who want to hand edit their config files, you might want
949 to now go to the <link linkend="act-examples">Actions Files Tutorial</link>.
950 The ideas explained therein also apply to the web-based editor.
953 There are also various
954 <link linkend="filter">filters</link> that can be used for ad blocking
955 (filters are a special subset of actions). These
956 fall into the <quote>advanced</quote> usage category, and are explained in
957 depth in later sections.
964 <!-- ~ End section ~ -->
967 <!-- ~~~~~ New section ~~~~~ -->
969 <title>Starting Privoxy</title>
971 Before launching <application>Privoxy</application> for the first time, you
972 will want to configure your browser(s) to use
973 <application>Privoxy</application> as a HTTP and HTTPS (SSL)
974 <ulink url="http://en.wikipedia.org/wiki/Proxy_server">proxy</ulink>. The default is
975 127.0.0.1 (or localhost) for the proxy address, and port 8118 (earlier versions
976 used port 8000). This is the one configuration step <emphasis>that must be done
980 Please note that <application>Privoxy</application> can only proxy HTTP and
981 HTTPS traffic. It will not work with FTP or other protocols.
984 <!-- image of Mozilla Proxy configuration -->
986 <figure pgwide="0" float="0"><title>Proxy Configuration Showing
987 Mozilla/Netscape HTTP and HTTPS (SSL) Settings</title>
990 <imagedata fileref="proxy_setup.jpg" format="jpg">
993 <phrase>[ Screenshot of Mozilla Proxy Configuration ]</phrase>
1001 With <application>Firefox</application>, this is typically set under:
1005 <guibutton>Tools</guibutton> -> <guibutton>Options</guibutton> -> <guibutton>Advanced</guibutton> -> <guibutton>Network</guibutton> -><guibutton>Connection</guibutton> -> <guibutton>Settings</guibutton>
1010 Or optionally on some platforms:
1014 <guibutton>Edit</guibutton> -> <guibutton>Preferences</guibutton> -> <guibutton>General</guibutton> -> <guibutton>Connection Settings</guibutton> -> <guibutton>Manual Proxy Configuration</guibutton>
1020 With <application>Netscape</application> (and
1021 <application>Mozilla</application>), this can be set under:
1026 <!-- Mix ascii and gui art, something for everybody -->
1027 <!-- spacing on this is tricky -->
1028 <guibutton>Edit</guibutton> -> <guibutton>Preferences</guibutton> -> <guibutton>Advanced</guibutton> -> <guibutton>Proxies</guibutton> -> <guibutton>HTTP Proxy</guibutton>
1033 For <application>Internet Explorer v.5-7</application>:
1037 <guibutton>Tools</guibutton> -> <guibutton>Internet Options</guibutton> -> <guibutton>Connections</guibutton> -> <guibutton>LAN Settings</guibutton>
1041 Then, check <quote>Use Proxy</quote> and fill in the appropriate info
1042 (Address: 127.0.0.1, Port: 8118). Include HTTPS (SSL), if you want HTTPS
1043 proxy support too (sometimes labeled <quote>Secure</quote>). Make sure any
1044 checkboxes like <quote>Use the same proxy server for all protocols</quote> is
1045 <emphasis>UNCHECKED</emphasis>. You want only HTTP and HTTPS (SSL)!
1048 <!-- image of IE Proxy configuration -->
1050 <figure pgwide="0" float="0"><title>Proxy Configuration Showing
1051 Internet Explorer HTTP and HTTPS (Secure) Settings</title>
1054 <imagedata fileref="proxy2.jpg" format="jpg">
1057 <phrase>[ Screenshot of IE Proxy Configuration ]</phrase>
1065 After doing this, flush your browser's disk and memory caches to force a
1066 re-reading of all pages and to get rid of any ads that may be cached. Remove
1067 any <ulink url="http://en.wikipedia.org/wiki/Browser_cookie">cookies</ulink>,
1068 if you want <application>Privoxy</application> to manage that. You are now
1069 ready to start enjoying the benefits of using
1070 <application>Privoxy</application>!
1074 <application>Privoxy</application> itself is typically started by specifying the
1075 main configuration file to be used on the command line. If no configuration
1076 file is specified on the command line, <application>Privoxy</application>
1077 will look for a file named <filename>config</filename> in the current
1078 directory. Except on Win32 where it will try <filename>config.txt</filename>.
1081 <sect2 id="start-redhat">
1082 <title>Red Hat and Fedora</title>
1084 A default Red Hat installation may not start &my-app; upon boot. It will use
1085 the file <filename>/etc/privoxy/config</filename> as its main configuration
1090 # /etc/rc.d/init.d/privoxy start
1098 # service privoxy start
1103 <sect2 id="start-debian">
1104 <title>Debian</title>
1106 We use a script. Note that Debian typically starts &my-app; upon booting per
1107 default. It will use the file
1108 <filename>/etc/privoxy/config</filename> as its main configuration
1113 # /etc/init.d/privoxy start
1118 <sect2 id="start-windows">
1119 <title>Windows</title>
1121 Click on the &my-app; Icon to start <application>Privoxy</application>. If no configuration file is
1122 specified on the command line, <application>Privoxy</application> will look
1123 for a file named <filename>config.txt</filename>. Note that Windows will
1124 automatically start &my-app; when the system starts if you chose that option
1128 <application>Privoxy</application> can run with full Windows service functionality.
1129 On Windows only, the &my-app; program has two new command line arguments
1130 to install and uninstall &my-app; as a service. See the
1131 <link linkend="installation-pack-win">Windows Installation
1132 instructions</link> for details.
1136 <sect2 id="start-unices">
1137 <title>Solaris, NetBSD, FreeBSD, HP-UX and others</title>
1139 Example Unix startup command:
1143 # /usr/sbin/privoxy /etc/privoxy/config
1148 <sect2 id="start-os2">
1151 During installation, <application>Privoxy</application> is configured to
1152 start automatically when the system restarts. You can start it manually by
1153 double-clicking on the <application>Privoxy</application> icon in the
1154 <application>Privoxy</application> folder.
1158 <sect2 id="start-macosx">
1159 <title>Mac OS X</title>
1161 After downloading the privoxy software, unzip the downloaded file by
1162 double-clicking on the zip file icon. Then, double-click on the
1163 installer package icon and follow the installation process.
1166 The privoxy service will automatically start after a successful
1167 installation. In addition, the privoxy service will automatically
1168 start every time your computer starts up.
1171 To prevent the privoxy service from automatically starting when your
1172 computer starts up, remove or rename the folder named
1173 /Library/StartupItems/Privoxy.
1176 A simple application named Privoxy Utility has been created which
1177 enables administrators to easily start and stop the privoxy service.
1180 In addition, the Privoxy Utility presents a simple way for
1181 administrators to edit the various privoxy config files. A method
1182 to uninstall the software is also available.
1185 An administrator username and password must be supplied in order for
1186 the Privoxy Utility to perform any of the tasks.
1191 <sect2 id="start-amigaos">
1192 <title>AmigaOS</title>
1194 Start <application>Privoxy</application> (with RUN <>NIL:) in your
1195 <filename>startnet</filename> script (AmiTCP), in
1196 <filename>s:user-startup</filename> (RoadShow), as startup program in your
1197 startup script (Genesis), or as startup action (Miami and MiamiDx).
1198 <application>Privoxy</application> will automatically quit when you quit your
1199 TCP/IP stack (just ignore the harmless warning your TCP/IP stack may display that
1200 <application>Privoxy</application> is still running).
1204 <sect2 id="start-gentoo">
1205 <title>Gentoo</title>
1207 A script is again used. It will use the file <filename>/etc/privoxy/config
1208 </filename> as its main configuration file.
1212 /etc/init.d/privoxy start
1216 Note that <application>Privoxy</application> is not automatically started at
1217 boot time by default. You can change this with the <literal>rc-update</literal>
1222 rc-update add privoxy default
1230 See the section <link linkend="cmdoptions">Command line options</link> for
1234 must find a better place for this paragraph
1237 The included default configuration files should give a reasonable starting
1238 point. Most of the per site configuration is done in the
1239 <ulink url="actions-file.html"><quote>actions</quote></ulink> files. These are
1240 where various cookie actions are defined, ad and banner blocking, and other
1241 aspects of <application>Privoxy</application> configuration. There are several
1242 such files included, with varying levels of aggressiveness.
1246 You will probably want to keep an eye out for sites for which you may prefer
1247 persistent cookies, and add these to your actions configuration as needed. By
1248 default, most of these will be accepted only during the current browser
1249 session (aka <quote>session cookies</quote>), unless you add them to the
1250 configuration. If you want the browser to handle this instead, you will need
1251 to edit <filename>user.action</filename> (or through the web based interface)
1252 and disable this feature. If you use more than one browser, it would make
1253 more sense to let <application>Privoxy</application> handle this. In which
1254 case, the browser(s) should be set to accept all cookies.
1258 Another feature where you will probably want to define exceptions for trusted
1259 sites is the popup-killing (through <ulink
1260 url="actions-file.html#FILTER-POPUPS"><quote>+filter{popups}</quote></ulink>),
1261 because your favorite shopping, banking, or leisure site may need
1262 popups (explained below).
1266 <application>Privoxy</application> does not support all of the optional HTTP/1.1
1267 features yet. In the unlikely event that you experience inexplicable problems
1268 with browsers that use HTTP/1.1 per default
1269 (like <application>Mozilla</application> or recent versions of I.E.), you might
1270 try to force HTTP/1.0 compatibility. For Mozilla, look under <literal>Edit ->
1271 Preferences -> Debug -> Networking</literal>.
1272 Alternatively, set the <quote>+downgrade-http-version</quote> config option in
1273 <filename>default.action</filename> which will downgrade your browser's HTTP
1274 requests from HTTP/1.1 to HTTP/1.0 before processing them.
1278 After running <application>Privoxy</application> for a while, you can
1279 start to fine tune the configuration to suit your personal, or site,
1280 preferences and requirements. There are many, many aspects that can
1281 be customized. <quote>Actions</quote>
1282 can be adjusted by pointing your browser to
1283 <ulink url="http://config.privoxy.org/">http://config.privoxy.org/</ulink>
1284 (shortcut: <ulink url="http://p.p/">http://p.p/</ulink>),
1285 and then follow the link to <quote>View & Change the Current Configuration</quote>.
1286 (This is an internal page and does not require Internet access.)
1290 In fact, various aspects of <application>Privoxy</application>
1291 configuration can be viewed from this page, including
1292 current configuration parameters, source code version numbers,
1293 the browser's request headers, and <quote>actions</quote> that apply
1294 to a given URL. In addition to the actions file
1295 editor mentioned above, <application>Privoxy</application> can also
1296 be turned <quote>on</quote> and <quote>off</quote> (toggled) from this page.
1300 If you encounter problems, try loading the page without
1301 <application>Privoxy</application>. If that helps, enter the URL where
1302 you have the problems into <ulink url="http://p.p/show-url-info">the browser
1303 based rule tracing utility</ulink>. See which rules apply and why, and
1304 then try turning them off for that site one after the other, until the problem
1305 is gone. When you have found the culprit, you might want to turn the rest on
1310 If the above paragraph sounds gibberish to you, you might want to <link
1311 linkend="actions-file">read more about the actions concept</link>
1312 or even dive deep into the <link linkend="actionsanat">Appendix
1317 If you can't get rid of the problem at all, think you've found a bug in
1318 Privoxy, want to propose a new feature or smarter rules, please see the
1319 section <link linkend="contact"><quote>Contacting the
1320 Developers</quote></link> below.
1325 <!-- ~~~~~ New section ~~~~~ -->
1326 <sect2 id="cmdoptions">
1327 <title>Command Line Options</title>
1329 <application>Privoxy</application> may be invoked with the following
1330 command-line options:
1338 <emphasis>--config-test</emphasis>
1341 Exit after loading the configuration files before binding to
1342 the listen address. The exit code signals whether or not the
1343 configuration files have been successfully loaded.
1346 If the exit code is 1, at least one of the configuration files
1347 is invalid, if it is 0, all the configuration files have been
1348 successfully loaded (but may still contain errors that can
1349 currently only be detected at run time).
1352 This option doesn't affect the log setting, combination with
1353 <emphasis>--no-daemon</emphasis> is recommended if a configured
1354 log file shouldn't be used.
1359 <emphasis>--version</emphasis>
1362 Print version info and exit. Unix only.
1367 <emphasis>--help</emphasis>
1370 Print short usage info and exit. Unix only.
1375 <emphasis>--no-daemon</emphasis>
1378 Don't become a daemon, i.e. don't fork and become process group
1379 leader, and don't detach from controlling tty. Unix only.
1384 <emphasis>--pidfile FILE</emphasis>
1387 On startup, write the process ID to <emphasis>FILE</emphasis>. Delete the
1388 <emphasis>FILE</emphasis> on exit. Failure to create or delete the
1389 <emphasis>FILE</emphasis> is non-fatal. If no <emphasis>FILE</emphasis>
1390 option is given, no PID file will be used. Unix only.
1395 <emphasis>--user USER[.GROUP]</emphasis>
1398 After (optionally) writing the PID file, assume the user ID of
1399 <emphasis>USER</emphasis>, and if included the GID of GROUP. Exit if the
1400 privileges are not sufficient to do so. Unix only.
1405 <emphasis>--chroot</emphasis>
1408 Before changing to the user ID given in the <emphasis>--user</emphasis> option,
1409 chroot to that user's home directory, i.e. make the kernel pretend to the &my-app;
1410 process that the directory tree starts there. If set up carefully, this can limit
1411 the impact of possible vulnerabilities in &my-app; to the files contained in that hierarchy.
1417 <emphasis>--pre-chroot-nslookup hostname</emphasis>
1420 Specifies a hostname to look up before doing a chroot. On some systems, initializing the
1421 resolver library involves reading config files from /etc and/or loading additional shared
1422 libraries from /lib. On these systems, doing a hostname lookup before the chroot reduces
1423 the number of files that must be copied into the chroot tree.
1426 For fastest startup speed, a good value is a hostname that is not in /etc/hosts but that
1427 your local name server (listed in /etc/resolv.conf) can resolve without recursion
1428 (that is, without having to ask any other name servers). The hostname need not exist,
1429 but if it doesn't, an error message (which can be ignored) will be output.
1435 <emphasis>configfile</emphasis>
1438 If no <emphasis>configfile</emphasis> is included on the command line,
1439 <application>Privoxy</application> will look for a file named
1440 <quote>config</quote> in the current directory (except on Win32
1441 where it will look for <quote>config.txt</quote> instead). Specify
1442 full path to avoid confusion. If no config file is found,
1443 <application>Privoxy</application> will fail to start.
1451 On <application>MS Windows</application> only there are two additional
1452 command-line options to allow <application>Privoxy</application> to install and
1453 run as a <emphasis>service</emphasis>. See the
1454 <link linkend="installation-pack-win">Window Installation section</link>
1462 <!-- ~ End section ~ -->
1465 <!-- ~~~~~ New section ~~~~~ -->
1466 <sect1 id="configuration"><title>Privoxy Configuration</title>
1468 All <application>Privoxy</application> configuration is stored
1469 in text files. These files can be edited with a text editor.
1470 Many important aspects of <application>Privoxy</application> can
1471 also be controlled easily with a web browser.
1475 <!-- ~~~~~ New section ~~~~~ -->
1478 <title>Controlling Privoxy with Your Web Browser</title>
1480 <application>Privoxy</application>'s user interface can be reached through the special
1481 URL <ulink url="http://config.privoxy.org/">http://config.privoxy.org/</ulink>
1482 (shortcut: <ulink url="http://p.p/">http://p.p/</ulink>),
1483 which is a built-in page and works without Internet access.
1484 You will see the following section:
1488 <!-- Needs to be put in a table and colorized -->
1491 <bridgehead renderas="sect2"> Privoxy Menu</bridgehead>
1495 ▪ <ulink url="http://config.privoxy.org/show-status">View & change the current configuration</ulink>
1498 ▪ <ulink url="http://config.privoxy.org/show-version">View the source code version numbers</ulink>
1501 ▪ <ulink url="http://config.privoxy.org/show-request">View the request headers.</ulink>
1504 ▪ <ulink url="http://config.privoxy.org/show-url-info">Look up which actions apply to a URL and why</ulink>
1507 ▪ <ulink url="http://config.privoxy.org/toggle">Toggle Privoxy on or off</ulink>
1510 ▪ <ulink
1511 url="http://www.privoxy.org/&p-version;/user-manual/">Documentation</ulink>
1519 This should be self-explanatory. Note the first item leads to an editor for the
1520 <link linkend="actions-file">actions files</link>, which is where the ad, banner,
1521 cookie, and URL blocking magic is configured as well as other advanced features of
1522 <application>Privoxy</application>. This is an easy way to adjust various
1523 aspects of <application>Privoxy</application> configuration. The actions
1524 file, and other configuration files, are explained in detail below.
1528 <quote>Toggle Privoxy On or Off</quote> is handy for sites that might
1529 have problems with your current actions and filters. You can in fact use
1530 it as a test to see whether it is <application>Privoxy</application>
1531 causing the problem or not. <application>Privoxy</application> continues
1532 to run as a proxy in this case, but all manipulation is disabled, i.e.
1533 <application>Privoxy</application> acts like a normal forwarding proxy. There
1534 is even a toggle <link linkend="bookmarklets">Bookmarklet</link> offered, so
1535 that you can toggle <application>Privoxy</application> with one click from
1540 Note that several of the features described above are disabled by default
1541 in <application>Privoxy</application> 3.0.7 beta and later.
1543 <ulink url="config.html">configuration file</ulink> to learn why
1544 and in which cases it's safe to enable them again.
1549 <!-- ~ End section ~ -->
1554 <!-- ~~~~~ New section ~~~~~ -->
1556 <sect2 id="confoverview">
1557 <title>Configuration Files Overview</title>
1559 For Unix, *BSD and Linux, all configuration files are located in
1560 <filename>/etc/privoxy/</filename> by default. For MS Windows, OS/2, and
1561 AmigaOS these are all in the same directory as the
1562 <application>Privoxy</application> executable. <![%p-not-stable;[ The name
1563 and number of configuration files has changed from previous versions, and is
1564 subject to change as development progresses.]]>
1568 The installed defaults provide a reasonable starting point, though
1569 some settings may be aggressive by some standards. For the time being, the
1570 principle configuration files are:
1578 The <link linkend="config">main configuration file</link> is named <filename>config</filename>
1579 on Linux, Unix, BSD, OS/2, and AmigaOS and <filename>config.txt</filename>
1580 on Windows. This is a required file.
1586 <filename>match-all.action</filename> is used to define which <quote>actions</quote>
1587 relating to banner-blocking, images, pop-ups, content modification, cookie handling
1588 etc should be applied by default. It should be the first actions file loaded.
1591 <filename>default.action</filename> defines many exceptions (both positive and negative)
1592 from the default set of actions that's configured in <filename>match-all.action</filename>.
1593 It should be the second actions file loaded and shouldn't be edited by the user.
1596 Multiple actions files may be defined in <filename>config</filename>. These
1597 are processed in the order they are defined. Local customizations and locally
1598 preferred exceptions to the default policies as defined in
1599 <filename>match-all.action</filename> (which you will most probably want
1600 to define sooner or later) are best applied in <filename>user.action</filename>,
1601 where you can preserve them across upgrades. The file isn't installed by all
1602 installers, but you can easily create it yourself with a text editor.
1605 There is also a web based editor that can be accessed from
1607 url="http://config.privoxy.org/show-status">http://config.privoxy.org/show-status</ulink>
1609 url="http://p.p/show-status">http://p.p/show-status</ulink>) for the
1610 various actions files.
1616 <quote>Filter files</quote> (the <link linkend="filter-file">filter
1617 file</link>) can be used to re-write the raw page content, including
1618 viewable text as well as embedded HTML and JavaScript, and whatever else
1619 lurks on any given web page. The filtering jobs are only pre-defined here;
1620 whether to apply them or not is up to the actions files.
1621 <filename>default.filter</filename> includes various filters made
1622 available for use by the developers. Some are much more intrusive than
1623 others, and all should be used with caution. You may define additional
1624 filter files in <filename>config</filename> as you can with
1625 actions files. We suggest <filename>user.filter</filename> for any
1626 locally defined filters or customizations.
1634 The syntax of the configuration and filter files may change between different
1635 Privoxy versions, unfortunately some enhancements cost backwards compatibility.
1636 <!-- Add link to documentation-->
1640 All files use the <quote><literal>#</literal></quote> character to denote a
1641 comment (the rest of the line will be ignored) and understand line continuation
1642 through placing a backslash ("<literal>\</literal>") as the very last character
1643 in a line. If the <literal>#</literal> is preceded by a backslash, it looses
1644 its special function. Placing a <literal>#</literal> in front of an otherwise
1645 valid configuration line to prevent it from being interpreted is called "commenting
1646 out" that line. Blank lines are ignored.
1650 The actions files and filter files
1651 can use Perl style <link linkend="regex">regular expressions</link> for
1652 maximum flexibility.
1656 After making any changes, there is no need to restart
1657 <application>Privoxy</application> in order for the changes to take
1658 effect. <application>Privoxy</application> detects such changes
1659 automatically. Note, however, that it may take one or two additional
1660 requests for the change to take effect. When changing the listening address
1661 of <application>Privoxy</application>, these <quote>wake up</quote> requests
1662 must obviously be sent to the <emphasis>old</emphasis> listening address.
1667 While under development, the configuration content is subject to change.
1668 The below documentation may not be accurate by the time you read this.
1669 Also, what constitutes a <quote>default</quote> setting, may change, so
1670 please check all your configuration files on important issues.
1676 <!-- ~ End section ~ -->
1679 <!-- ~~~~~~~~ New section Header ~~~~~~~~~ -->
1681 <!-- **************************************************** -->
1682 <!-- Include config.sgml here -->
1683 <!-- This is where the entire config file is detailed. -->
1685 <!-- end include -->
1688 <!-- ~ End section ~ -->
1692 <!-- ~~~~~~~~ New section Header ~~~~~~~~~ -->
1694 <sect1 id="actions-file"><title>Actions Files</title>
1698 XXX: similar descriptions are in the Configuration Files sections.
1699 We should only describe them at one place.
1702 The actions files are used to define what <emphasis>actions</emphasis>
1703 <application>Privoxy</application> takes for which URLs, and thus determines
1704 how ad images, cookies and various other aspects of HTTP content and
1705 transactions are handled, and on which sites (or even parts thereof).
1706 There are a number of such actions, with a wide range of functionality.
1707 Each action does something a little different.
1708 These actions give us a veritable arsenal of tools with which to exert
1709 our control, preferences and independence. Actions can be combined so that
1710 their effects are aggregated when applied against a given set of URLs.
1714 are three action files included with <application>Privoxy</application> with
1721 <filename>match-all.action</filename> - is used to define which
1722 <quote>actions</quote> relating to banner-blocking, images, pop-ups,
1723 content modification, cookie handling etc should be applied by default.
1724 It should be the first actions file loaded
1729 <filename>default.action</filename> - defines many exceptions (both
1730 positive and negative) from the default set of actions that's configured
1731 in <filename>match-all.action</filename>. It is a set of rules that should
1732 work reasonably well as-is for most users. This file is only supposed to
1733 be edited by the developers. It should be the second actions file loaded.
1738 <filename>user.action</filename> - is intended to be for local site
1739 preferences and exceptions. As an example, if your ISP or your bank
1740 has specific requirements, and need special handling, this kind of
1741 thing should go here. This file will not be upgraded.
1746 <guibutton>Edit</guibutton> <guibutton>Set to Cautious</guibutton> <guibutton>Set to Medium</guibutton> <guibutton>Set to Advanced</guibutton>
1749 These have increasing levels of aggressiveness <emphasis>and have no
1750 influence on your browsing unless you select them explicitly in the
1751 editor</emphasis>. A default installation should be pre-set to
1752 <literal>Cautious</literal>. New users should try this for a while before
1753 adjusting the settings to more aggressive levels. The more aggressive
1754 the settings, then the more likelihood there is of problems such as sites
1755 not working as they should.
1758 The <guibutton>Edit</guibutton> button allows you to turn each
1759 action on/off individually for fine-tuning. The <guibutton>Cautious</guibutton>
1760 button changes the actions list to low/safe settings which will activate
1761 ad blocking and a minimal set of &my-app;'s features, and subsequently
1762 there will be less of a chance for accidental problems. The
1763 <guibutton>Medium</guibutton> button sets the list to a medium level of
1764 other features and a low level set of privacy features. The
1765 <guibutton>Advanced</guibutton> button sets the list to a high level of
1766 ad blocking and medium level of privacy. See the chart below. The latter
1767 three buttons over-ride any changes via with the
1768 <guibutton>Edit</guibutton> button. More fine-tuning can be done in the
1769 lower sections of this internal page.
1772 While the actions file editor allows to enable these settings in all
1773 actions files, they are only supposed to be enabled in the first one
1774 to make sure you don't unintentionally overrule earlier rules.
1777 The default profiles, and their associated actions, as pre-defined in
1778 <filename>default.action</filename> are:
1781 <table frame=all><title>Default Configurations</title>
1782 <tgroup cols=4 align=left colsep=1 rowsep=1>
1783 <colspec colname=c1>
1784 <colspec colname=c2>
1785 <colspec colname=c3>
1786 <colspec colname=c4>
1789 <entry>Feature</entry>
1790 <entry>Cautious</entry>
1791 <entry>Medium</entry>
1792 <entry>Advanced</entry>
1797 <!-- <entry>f1</entry> -->
1798 <!-- <entry>f2</entry> -->
1799 <!-- <entry>f3</entry> -->
1800 <!-- <entry>f4</entry> -->
1806 <entry>Ad-blocking Aggressiveness</entry>
1807 <entry>medium</entry>
1813 <entry>Ad-filtering by size</entry>
1820 <entry>Ad-filtering by link</entry>
1826 <entry>Pop-up killing</entry>
1827 <entry>blocks only</entry>
1828 <entry>blocks only</entry>
1829 <entry>blocks only</entry>
1833 <entry>Privacy Features</entry>
1835 <entry>medium</entry>
1836 <entry>medium/high</entry>
1840 <entry>Cookie handling</entry>
1842 <entry>session-only</entry>
1847 <entry>Referer forging</entry>
1854 <entry>GIF de-animation</entry>
1861 <entry>Fast redirects</entry>
1868 <entry>HTML taming</entry>
1875 <entry>JavaScript taming</entry>
1882 <entry>Web-bug killing</entry>
1889 <entry>Image tag reordering</entry>
1905 The list of actions files to be used are defined in the main configuration
1906 file, and are processed in the order they are defined (e.g.
1907 <filename>default.action</filename> is typically processed before
1908 <filename>user.action</filename>). The content of these can all be viewed and
1910 url="http://config.privoxy.org/show-status">http://config.privoxy.org/show-status</ulink>.
1911 The over-riding principle when applying actions, is that the last action that
1912 matches a given URL wins. The broadest, most general rules go first
1913 (defined in <filename>default.action</filename>),
1914 followed by any exceptions (typically also in
1915 <filename>default.action</filename>), which are then followed lastly by any
1916 local preferences (typically in <emphasis>user</emphasis><filename>.action</filename>).
1917 Generally, <filename>user.action</filename> has the last word.
1921 An actions file typically has multiple sections. If you want to use
1922 <quote>aliases</quote> in an actions file, you have to place the (optional)
1923 <link linkend="aliases">alias section</link> at the top of that file.
1924 Then comes the default set of rules which will apply universally to all
1925 sites and pages (be <emphasis>very careful</emphasis> with using such a
1926 universal set in <filename>user.action</filename> or any other actions file after
1927 <filename>default.action</filename>, because it will override the result
1928 from consulting any previous file). And then below that,
1929 exceptions to the defined universal policies. You can regard
1930 <filename>user.action</filename> as an appendix to <filename>default.action</filename>,
1931 with the advantage that it is a separate file, which makes preserving your
1932 personal settings across <application>Privoxy</application> upgrades easier.
1936 Actions can be used to block anything you want, including ads, banners, or
1937 just some obnoxious URL whose content you would rather not see. Cookies can be accepted
1938 or rejected, or accepted only during the current browser session (i.e. not
1939 written to disk), content can be modified, some JavaScripts tamed, user-tracking
1940 fooled, and much more. See below for a <link linkend="actions">complete list
1944 <!-- ~~~~~ New section ~~~~~ -->
1946 <title>Finding the Right Mix</title>
1948 Note that some <link linkend="actions">actions</link>, like cookie suppression
1949 or script disabling, may render some sites unusable that rely on these
1950 techniques to work properly. Finding the right mix of actions is not always easy and
1951 certainly a matter of personal taste. And, things can always change, requiring
1952 refinements in the configuration. In general, it can be said that the more
1953 <quote>aggressive</quote> your default settings (in the top section of the
1954 actions file) are, the more exceptions for <quote>trusted</quote> sites you
1955 will have to make later. If, for example, you want to crunch all cookies per
1956 default, you'll have to make exceptions from that rule for sites that you
1957 regularly use and that require cookies for actually useful purposes, like maybe
1958 your bank, favorite shop, or newspaper.
1962 We have tried to provide you with reasonable rules to start from in the
1963 distribution actions files. But there is no general rule of thumb on these
1964 things. There just are too many variables, and sites are constantly changing.
1965 Sooner or later you will want to change the rules (and read this chapter again :).
1969 <!-- ~~~~~ New section ~~~~~ -->
1971 <title>How to Edit</title>
1973 The easiest way to edit the actions files is with a browser by
1974 using our browser-based editor, which can be reached from <ulink
1975 url="http://config.privoxy.org/show-status">http://config.privoxy.org/show-status</ulink>.
1976 Note: the config file option <link
1977 linkend="enable-edit-actions">enable-edit-actions</link> must be enabled for
1978 this to work. The editor allows both fine-grained control over every single
1979 feature on a per-URL basis, and easy choosing from wholesale sets of defaults
1980 like <quote>Cautious</quote>, <quote>Medium</quote> or
1981 <quote>Advanced</quote>. Warning: the <quote>Advanced</quote> setting is more
1982 aggressive, and will be more likely to cause problems for some sites.
1983 Experienced users only!
1987 If you prefer plain text editing to GUIs, you can of course also directly edit the
1988 the actions files with your favorite text editor. Look at
1989 <filename>default.action</filename> which is richly commented with many
1995 <sect2 id="actions-apply">
1996 <title>How Actions are Applied to Requests</title>
1998 Actions files are divided into sections. There are special sections,
1999 like the <quote><link linkend="aliases">alias</link></quote> sections which will
2000 be discussed later. For now let's concentrate on regular sections: They have a
2001 heading line (often split up to multiple lines for readability) which consist
2002 of a list of actions, separated by whitespace and enclosed in curly braces.
2003 Below that, there is a list of URL and tag patterns, each on a separate line.
2007 To determine which actions apply to a request, the URL of the request is
2008 compared to all URL patterns in each <quote>action file</quote>.
2009 Every time it matches, the list of applicable actions for the request is
2010 incrementally updated, using the heading of the section in which the
2011 pattern is located. The same is done again for tags and tag patterns later on.
2015 If multiple applying sections set the same action differently,
2016 the last match wins. If not, the effects are aggregated.
2017 E.g. a URL might match a regular section with a heading line of <literal>{
2018 +<link linkend="handle-as-image">handle-as-image</link> }</literal>,
2019 then later another one with just <literal>{
2020 +<link linkend="block">block</link> }</literal>, resulting
2021 in <emphasis>both</emphasis> actions to apply. And there may well be
2022 cases where you will want to combine actions together. Such a section then
2028 { +<literal>handle-as-image</literal> +<literal>block{Banner ads.}</literal> }
2029 # Block these as if they were images. Send no block page.
2031 media.example.com/.*banners
2032 .example.com/images/ads/</screen>
2036 You can trace this process for URL patterns and any given URL by visiting <ulink
2037 url="http://config.privoxy.org/show-url-info">http://config.privoxy.org/show-url-info</ulink>.
2041 Examples and more detail on this is provided in the Appendix, <link linkend="ACTIONSANAT">
2042 Troubleshooting: Anatomy of an Action</link> section.
2046 <!-- ~~~~~ New section ~~~~~ -->
2047 <sect2 id="af-patterns">
2048 <title>Patterns</title>
2050 As mentioned, <application>Privoxy</application> uses <quote>patterns</quote>
2051 to determine what <emphasis>actions</emphasis> might apply to which sites and
2052 pages your browser attempts to access. These <quote>patterns</quote> use wild
2053 card type <emphasis>pattern</emphasis> matching to achieve a high degree of
2054 flexibility. This allows one expression to be expanded and potentially match
2055 against many similar patterns.
2059 Generally, an URL pattern has the form
2060 <literal><domain><port>/<path></literal>, where the
2061 <literal><domain></literal>, the <literal><port></literal>
2062 and the <literal><path></literal> are optional. (This is why the special
2063 <literal>/</literal> pattern matches all URLs). Note that the protocol
2064 portion of the URL pattern (e.g. <literal>http://</literal>) should
2065 <emphasis>not</emphasis> be included in the pattern. This is assumed already!
2068 The pattern matching syntax is different for the domain and path parts of
2069 the URL. The domain part uses a simple globbing type matching technique,
2070 while the path part uses more flexible
2071 <ulink url="http://en.wikipedia.org/wiki/Regular_expressions"><quote>Regular
2072 Expressions</quote></ulink> (POSIX 1003.2).
2075 The port part of a pattern is a decimal port number preceded by a colon
2076 (<literal>:</literal>). If the domain part contains a numerical IPv6 address,
2077 it has to be put into angle brackets
2078 (<literal><</literal>, <literal>></literal>).
2083 <term><literal>www.example.com/</literal></term>
2086 is a domain-only pattern and will match any request to <literal>www.example.com</literal>,
2087 regardless of which document on that server is requested. So ALL pages in
2088 this domain would be covered by the scope of this action. Note that a
2089 simple <literal>example.com</literal> is different and would NOT match.
2094 <term><literal>www.example.com</literal></term>
2097 means exactly the same. For domain-only patterns, the trailing <literal>/</literal> may
2103 <term><literal>www.example.com/index.html</literal></term>
2106 matches all the documents on <literal>www.example.com</literal>
2107 whose name starts with <literal>/index.html</literal>.
2112 <term><literal>www.example.com/index.html$</literal></term>
2115 matches only the single document <literal>/index.html</literal>
2116 on <literal>www.example.com</literal>.
2121 <term><literal>/index.html$</literal></term>
2124 matches the document <literal>/index.html</literal>, regardless of the domain,
2125 i.e. on <emphasis>any</emphasis> web server anywhere.
2130 <term><literal>/</literal></term>
2133 Matches any URL because there's no requirement for either the
2134 domain or the path to match anything.
2139 <term><literal>:8000/</literal></term>
2142 Matches any URL pointing to TCP port 8000.
2147 <term><literal><2001:db8::1>/</literal></term>
2150 Matches any URL with the host address <literal>2001:db8::1</literal>.
2151 (Note that the real URL uses plain brackets, not angle brackets.)
2156 <term><literal>index.html</literal></term>
2159 matches nothing, since it would be interpreted as a domain name and
2160 there is no top-level domain called <literal>.html</literal>. So its
2168 <!-- ~~~~~ New section ~~~~~ -->
2169 <sect3><title>The Domain Pattern</title>
2172 The matching of the domain part offers some flexible options: if the
2173 domain starts or ends with a dot, it becomes unanchored at that end.
2179 <term><literal>.example.com</literal></term>
2182 matches any domain with first-level domain <literal>com</literal>
2183 and second-level domain <literal>example</literal>.
2184 For example <literal>www.example.com</literal>,
2185 <literal>example.com</literal> and <literal>foo.bar.baz.example.com</literal>.
2186 Note that it wouldn't match if the second-level domain was <literal>another-example</literal>.
2191 <term><literal>www.</literal></term>
2194 matches any domain that <emphasis>STARTS</emphasis> with
2195 <literal>www.</literal> (It also matches the domain
2196 <literal>www</literal> but most of the time that doesn't matter.)
2201 <term><literal>.example.</literal></term>
2204 matches any domain that <emphasis>CONTAINS</emphasis> <literal>.example.</literal>.
2205 And, by the way, also included would be any files or documents that exist
2206 within that domain since no path limitations are specified. (Correctly
2207 speaking: It matches any FQDN that contains <literal>example</literal> as
2208 a domain.) This might be <literal>www.example.com</literal>,
2209 <literal>news.example.de</literal>, or
2210 <literal>www.example.net/cgi/testing.pl</literal> for instance. All these
2218 Additionally, there are wild-cards that you can use in the domain names
2219 themselves. These work similarly to shell globbing type wild-cards:
2220 <quote>*</quote> represents zero or more arbitrary characters (this is
2222 <ulink url="http://en.wikipedia.org/wiki/Regular_expressions"><quote>Regular
2223 Expression</quote></ulink> based syntax of <quote>.*</quote>),
2224 <quote>?</quote> represents any single character (this is equivalent to the
2225 regular expression syntax of a simple <quote>.</quote>), and you can define
2226 <quote>character classes</quote> in square brackets which is similar to
2227 the same regular expression technique. All of this can be freely mixed:
2232 <term><literal>ad*.example.com</literal></term>
2235 matches <quote>adserver.example.com</quote>,
2236 <quote>ads.example.com</quote>, etc but not <quote>sfads.example.com</quote>
2241 <term><literal>*ad*.example.com</literal></term>
2244 matches all of the above, and then some.
2249 <term><literal>.?pix.com</literal></term>
2252 matches <literal>www.ipix.com</literal>,
2253 <literal>pictures.epix.com</literal>, <literal>a.b.c.d.e.upix.com</literal> etc.
2258 <term><literal>www[1-9a-ez].example.c*</literal></term>
2261 matches <literal>www1.example.com</literal>,
2262 <literal>www4.example.cc</literal>, <literal>wwwd.example.cy</literal>,
2263 <literal>wwwz.example.com</literal> etc., but <emphasis>not</emphasis>
2264 <literal>wwww.example.com</literal>.
2271 While flexible, this is not the sophistication of full regular expression based syntax.
2276 <!-- ~ End section ~ -->
2279 <!-- ~~~~~ New section ~~~~~ -->
2280 <sect3><title>The Path Pattern</title>
2283 <application>Privoxy</application> uses <quote>modern</quote> POSIX 1003.2
2284 <ulink url="http://en.wikipedia.org/wiki/Regular_expressions"><quote>Regular
2285 Expressions</quote></ulink> for matching the path portion (after the slash),
2286 and is thus more flexible.
2290 There is an <link linkend="regex">Appendix</link> with a brief quick-start into regular
2291 expressions, you also might want to have a look at your operating system's documentation
2292 on regular expressions (try <literal>man re_format</literal>).
2296 Note that the path pattern is automatically left-anchored at the <quote>/</quote>,
2297 i.e. it matches as if it would start with a <quote>^</quote> (regular expression speak
2298 for the beginning of a line).
2302 Please also note that matching in the path is <emphasis>CASE INSENSITIVE</emphasis>
2303 by default, but you can switch to case sensitive at any point in the pattern by using the
2304 <quote>(?-i)</quote> switch: <literal>www.example.com/(?-i)PaTtErN.*</literal> will match
2305 only documents whose path starts with <literal>PaTtErN</literal> in
2306 <emphasis>exactly</emphasis> this capitalization.
2311 <term><literal>.example.com/.*</literal></term>
2314 Is equivalent to just <quote>.example.com</quote>, since any documents
2315 within that domain are matched with or without the <quote>.*</quote>
2316 regular expression. This is redundant
2321 <term><literal>.example.com/.*/index.html$</literal></term>
2324 Will match any page in the domain of <quote>example.com</quote> that is
2325 named <quote>index.html</quote>, and that is part of some path. For
2326 example, it matches <quote>www.example.com/testing/index.html</quote> but
2327 NOT <quote>www.example.com/index.html</quote> because the regular
2328 expression called for at least two <quote>/'s</quote>, thus the path
2329 requirement. It also would match
2330 <quote>www.example.com/testing/index_html</quote>, because of the
2331 special meta-character <quote>.</quote>.
2336 <term><literal>.example.com/(.*/)?index\.html$</literal></term>
2339 This regular expression is conditional so it will match any page
2340 named <quote>index.html</quote> regardless of path which in this case can
2341 have one or more <quote>/'s</quote>. And this one must contain exactly
2342 <quote>.html</quote> (but does not have to end with that!).
2347 <term><literal>.example.com/(.*/)(ads|banners?|junk)</literal></term>
2350 This regular expression will match any path of <quote>example.com</quote>
2351 that contains any of the words <quote>ads</quote>, <quote>banner</quote>,
2352 <quote>banners</quote> (because of the <quote>?</quote>) or <quote>junk</quote>.
2353 The path does not have to end in these words, just contain them.
2358 <term><literal>.example.com/(.*/)(ads|banners?|junk)/.*\.(jpe?g|gif|png)$</literal></term>
2361 This is very much the same as above, except now it must end in either
2362 <quote>.jpg</quote>, <quote>.jpeg</quote>, <quote>.gif</quote> or <quote>.png</quote>. So this
2363 one is limited to common image formats.
2370 There are many, many good examples to be found in <filename>default.action</filename>,
2371 and more tutorials below in <link linkend="regex">Appendix on regular expressions</link>.
2376 <!-- ~ End section ~ -->
2379 <!-- ~~~~~ New section ~~~~~ -->
2380 <sect3 id="tag-pattern"><title>The Tag Pattern</title>
2383 Tag patterns are used to change the applying actions based on the
2384 request's tags. Tags can be created with either the
2385 <link linkend="CLIENT-HEADER-TAGGER">client-header-tagger</link>
2386 or the <link linkend="SERVER-HEADER-TAGGER">server-header-tagger</link> action.
2390 Tag patterns have to start with <quote>TAG:</quote>, so &my-app;
2391 can tell them apart from URL patterns. Everything after the colon
2392 including white space, is interpreted as a regular expression with
2393 path pattern syntax, except that tag patterns aren't left-anchored
2394 automatically (&my-app; doesn't silently add a <quote>^</quote>,
2395 you have to do it yourself if you need it).
2399 To match all requests that are tagged with <quote>foo</quote>
2400 your pattern line should be <quote>TAG:^foo$</quote>,
2401 <quote>TAG:foo</quote> would work as well, but it would also
2402 match requests whose tags contain <quote>foo</quote> somewhere.
2403 <quote>TAG: foo</quote> wouldn't work as it requires white space.
2407 Sections can contain URL and tag patterns at the same time,
2408 but tag patterns are checked after the URL patterns and thus
2409 always overrule them, even if they are located before the URL patterns.
2413 Once a new tag is added, Privoxy checks right away if it's matched by one
2414 of the tag patterns and updates the action settings accordingly. As a result
2415 tags can be used to activate other tagger actions, as long as these other
2416 taggers look for headers that haven't already be parsed.
2420 For example you could tag client requests which use the
2421 <literal>POST</literal> method,
2422 then use this tag to activate another tagger that adds a tag if cookies
2423 are sent, and then use a block action based on the cookie tag. This allows
2424 the outcome of one action, to be input into a subsequent action. However if
2425 you'd reverse the position of the described taggers, and activated the
2426 method tagger based on the cookie tagger, no method tags would be created.
2427 The method tagger would look for the request line, but at the time
2428 the cookie tag is created, the request line has already been parsed.
2432 While this is a limitation you should be aware of, this kind of
2433 indirection is seldom needed anyway and even the example doesn't
2434 make too much sense.
2441 <!-- ~ End section ~ -->
2444 <!-- ~~~~~ New section ~~~~~ -->
2446 <sect2 id="actions">
2447 <title>Actions</title>
2449 All actions are disabled by default, until they are explicitly enabled
2450 somewhere in an actions file. Actions are turned on if preceded with a
2451 <quote>+</quote>, and turned off if preceded with a <quote>-</quote>. So a
2452 <literal>+action</literal> means <quote>do that action</quote>, e.g.
2453 <literal>+block</literal> means <quote>please block URLs that match the
2454 following patterns</quote>, and <literal>-block</literal> means <quote>don't
2455 block URLs that match the following patterns, even if <literal>+block</literal>
2456 previously applied.</quote>
2461 Again, actions are invoked by placing them on a line, enclosed in curly braces and
2462 separated by whitespace, like in
2463 <literal>{+some-action -some-other-action{some-parameter}}</literal>,
2464 followed by a list of URL patterns, one per line, to which they apply.
2465 Together, the actions line and the following pattern lines make up a section
2466 of the actions file.
2470 Actions fall into three categories:
2477 Boolean, i.e the action can only be <quote>enabled</quote> or
2478 <quote>disabled</quote>. Syntax:
2482 +<replaceable class="function">name</replaceable> # enable action <replaceable class="parameter">name</replaceable>
2483 -<replaceable class="function">name</replaceable> # disable action <replaceable class="parameter">name</replaceable></screen>
2486 Example: <literal>+handle-as-image</literal>
2493 Parameterized, where some value is required in order to enable this type of action.
2498 +<replaceable class="function">name</replaceable>{<replaceable class="parameter">param</replaceable>} # enable action and set parameter to <replaceable class="parameter">param</replaceable>,
2499 # overwriting parameter from previous match if necessary
2500 -<replaceable class="function">name</replaceable> # disable action. The parameter can be omitted</screen>
2503 Note that if the URL matches multiple positive forms of a parameterized action,
2504 the last match wins, i.e. the params from earlier matches are simply ignored.
2507 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>
2513 Multi-value. These look exactly like parameterized actions,
2514 but they behave differently: If the action applies multiple times to the
2515 same URL, but with different parameters, <emphasis>all</emphasis> the parameters
2516 from <emphasis>all</emphasis> matches are remembered. This is used for actions
2517 that can be executed for the same request repeatedly, like adding multiple
2518 headers, or filtering through multiple filters. Syntax:
2522 +<replaceable class="function">name</replaceable>{<replaceable class="parameter">param</replaceable>} # enable action and add <replaceable class="parameter">param</replaceable> to the list of parameters
2523 -<replaceable class="function">name</replaceable>{<replaceable class="parameter">param</replaceable>} # remove the parameter <replaceable class="parameter">param</replaceable> from the list of parameters
2524 # If it was the last one left, disable the action.
2525 <replaceable class="parameter">-name</replaceable> # disable this action completely and remove all parameters from the list</screen>
2528 Examples: <literal>+add-header{X-Fun-Header: Some text}</literal> and
2529 <literal>+filter{html-annoyances}</literal>
2537 If nothing is specified in any actions file, no <quote>actions</quote> are
2538 taken. So in this case <application>Privoxy</application> would just be a
2539 normal, non-blocking, non-filtering proxy. You must specifically enable the
2540 privacy and blocking features you need (although the provided default actions
2541 files will give a good starting point).
2545 Later defined action sections always over-ride earlier ones of the same type.
2546 So exceptions to any rules you make, should come in the latter part of the file (or
2547 in a file that is processed later when using multiple actions files such
2548 as <filename>user.action</filename>). For multi-valued actions, the actions
2549 are applied in the order they are specified. Actions files are processed in
2550 the order they are defined in <filename>config</filename> (the default
2551 installation has three actions files). It also quite possible for any given
2552 URL to match more than one <quote>pattern</quote> (because of wildcards and
2553 regular expressions), and thus to trigger more than one set of actions! Last
2557 <!-- start actions listing -->
2559 The list of valid <application>Privoxy</application> actions are:
2563 <!-- ********************************************************** -->
2564 <!-- Please note the below defined actions use id's that are -->
2565 <!-- probably linked from other places, so please don't change. -->
2567 <!-- ********************************************************** -->
2570 <!-- ~~~~~ New section ~~~~~ -->
2572 <sect3 renderas="sect4" id="add-header">
2573 <title>add-header</title>
2577 <term>Typical use:</term>
2579 <para>Confuse log analysis, custom applications</para>
2584 <term>Effect:</term>
2587 Sends a user defined HTTP header to the web server.
2594 <!-- boolean, parameterized, Multi-value -->
2596 <para>Multi-value.</para>
2601 <term>Parameter:</term>
2604 Any string value is possible. Validity of the defined HTTP headers is not checked.
2605 It is recommended that you use the <quote><literal>X-</literal></quote> prefix
2615 This action may be specified multiple times, in order to define multiple
2616 headers. This is rarely needed for the typical user. If you don't know what
2617 <quote>HTTP headers</quote> are, you definitely don't need to worry about this
2621 Headers added by this action are not modified by other actions.
2627 <term>Example usage:</term>
2630 <screen>+add-header{X-User-Tracking: sucks}</screen>
2638 <!-- ~~~~~ New section ~~~~~ -->
2639 <sect3 renderas="sect4" id="block">
2640 <title>block</title>
2644 <term>Typical use:</term>
2646 <para>Block ads or other unwanted content</para>
2651 <term>Effect:</term>
2654 Requests for URLs to which this action applies are blocked, i.e. the
2655 requests are trapped by &my-app; and the requested URL is never retrieved,
2656 but is answered locally with a substitute page or image, as determined by
2658 linkend="handle-as-image">handle-as-image</link></literal>,
2660 linkend="set-image-blocker">set-image-blocker</link></literal>, and
2662 linkend="handle-as-empty-document">handle-as-empty-document</link></literal> actions.
2670 <!-- boolean, parameterized, Multi-value -->
2672 <para>Parameterized.</para>
2677 <term>Parameter:</term>
2679 <para>A block reason that should be given to the user.</para>
2687 <application>Privoxy</application> sends a special <quote>BLOCKED</quote> page
2688 for requests to blocked pages. This page contains the block reason given as
2689 parameter, a link to find out why the block action applies, and a click-through
2690 to the blocked content (the latter only if the force feature is available and
2694 A very important exception occurs if <emphasis>both</emphasis>
2695 <literal>block</literal> and <literal><link linkend="handle-as-image">handle-as-image</link></literal>,
2696 apply to the same request: it will then be replaced by an image. If
2697 <literal><link linkend="set-image-blocker">set-image-blocker</link></literal>
2698 (see below) also applies, the type of image will be determined by its parameter,
2699 if not, the standard checkerboard pattern is sent.
2702 It is important to understand this process, in order
2703 to understand how <application>Privoxy</application> deals with
2704 ads and other unwanted content. Blocking is a core feature, and one
2705 upon which various other features depend.
2708 The <literal><link linkend="filter">filter</link></literal>
2709 action can perform a very similar task, by <quote>blocking</quote>
2710 banner images and other content through rewriting the relevant URLs in the
2711 document's HTML source, so they don't get requested in the first place.
2712 Note that this is a totally different technique, and it's easy to confuse the two.
2718 <term>Example usage (section):</term>
2721 <screen>{+block{No nasty stuff for you.}}
2722 # Block and replace with "blocked" page
2723 .nasty-stuff.example.com
2725 {+block{Doubleclick banners.} +handle-as-image}
2726 # Block and replace with image
2730 {+block{Layered ads.} +handle-as-empty-document}
2731 # Block and then ignore
2732 adserver.example.net/.*\.js$</screen>
2742 <!-- ~~~~~ New section ~~~~~ -->
2743 <sect3 renderas="sect4" id="change-x-forwarded-for">
2744 <title>change-x-forwarded-for</title>
2748 <term>Typical use:</term>
2750 <para>Improve privacy by not forwarding the source of the request in the HTTP headers.</para>
2755 <term>Effect:</term>
2758 Deletes the <quote>X-Forwarded-For:</quote> HTTP header from the client request,
2766 <!-- Boolean, Parameterized, Multi-value -->
2768 <para>Parameterized.</para>
2773 <term>Parameter:</term>
2777 <para><quote>block</quote> to delete the header.</para>
2781 <quote>add</quote> to create the header (or append
2782 the client's IP address to an already existing one).
2793 It is safe and recommended to use <literal>block</literal>.
2796 Forwarding the source address of the request may make
2797 sense in some multi-user setups but is also a privacy risk.
2802 <term>Example usage:</term>
2805 <screen>+change-x-forwarded-for{block}</screen>
2812 <!-- ~~~~~ New section ~~~~~ -->
2813 <sect3 renderas="sect4" id="client-header-filter">
2814 <title>client-header-filter</title>
2818 <term>Typical use:</term>
2821 Rewrite or remove single client headers.
2827 <term>Effect:</term>
2830 All client headers to which this action applies are filtered on-the-fly through
2831 the specified regular expression based substitutions.
2838 <!-- boolean, parameterized, Multi-value -->
2840 <para>Parameterized.</para>
2845 <term>Parameter:</term>
2848 The name of a client-header filter, as defined in one of the
2849 <link linkend="filter-file">filter files</link>.
2858 Client-header filters are applied to each header on its own, not to
2859 all at once. This makes it easier to diagnose problems, but on the downside
2860 you can't write filters that only change header x if header y's value is z.
2861 You can do that by using tags though.
2864 Client-header filters are executed after the other header actions have finished
2865 and use their output as input.
2868 If the request URI gets changed, &my-app; will detect that and use the new
2869 one. This can be used to rewrite the request destination behind the client's
2870 back, for example to specify a Tor exit relay for certain requests.
2873 Please refer to the <link linkend="filter-file">filter file chapter</link>
2874 to learn which client-header filters are available by default, and how to
2882 <term>Example usage (section):</term>
2886 # Hide Tor exit notation in Host and Referer Headers
2887 {+client-header-filter{hide-tor-exit-notation}}
2898 <!-- ~~~~~ New section ~~~~~ -->
2899 <sect3 renderas="sect4" id="client-header-tagger">
2900 <title>client-header-tagger</title>
2904 <term>Typical use:</term>
2907 Block requests based on their headers.
2913 <term>Effect:</term>
2916 Client headers to which this action applies are filtered on-the-fly through
2917 the specified regular expression based substitutions, the result is used as
2925 <!-- boolean, parameterized, Multi-value -->
2927 <para>Parameterized.</para>
2932 <term>Parameter:</term>
2935 The name of a client-header tagger, as defined in one of the
2936 <link linkend="filter-file">filter files</link>.
2945 Client-header taggers are applied to each header on its own,
2946 and as the header isn't modified, each tagger <quote>sees</quote>
2950 Client-header taggers are the first actions that are executed
2951 and their tags can be used to control every other action.
2957 <term>Example usage (section):</term>
2961 # Tag every request with the User-Agent header
2962 {+client-header-tagger{user-agent}}
2965 # Tagging itself doesn't change the action
2966 # settings, sections with TAG patterns do:
2968 # If it's a download agent, use a different forwarding proxy,
2969 # show the real User-Agent and make sure resume works.
2970 {+forward-override{forward-socks5 10.0.0.2:2222 .} \
2971 -hide-if-modified-since \
2972 -overwrite-last-modified \
2977 TAG:^User-Agent: NetBSD-ftp/
2978 TAG:^User-Agent: Novell ZYPP Installer
2979 TAG:^User-Agent: RPM APT-HTTP/
2980 TAG:^User-Agent: fetch libfetch/
2981 TAG:^User-Agent: Ubuntu APT-HTTP/
2982 TAG:^User-Agent: MPlayer/
2987 # Tag all requests with the Range header set
2988 {+client-header-tagger{range-requests}}
2991 # Disable filtering for the tagged requests.
2993 # With filtering enabled Privoxy would remove the Range headers
2994 # to be able to filter the whole response. The downside is that
2995 # it prevents clients from resuming downloads or skipping over
2996 # parts of multimedia files.
2997 {-filter -deanimate-gifs}
3008 <!-- ~~~~~ New section ~~~~~ -->
3009 <sect3 renderas="sect4" id="content-type-overwrite">
3010 <title>content-type-overwrite</title>
3014 <term>Typical use:</term>
3016 <para>Stop useless download menus from popping up, or change the browser's rendering mode</para>
3021 <term>Effect:</term>
3024 Replaces the <quote>Content-Type:</quote> HTTP server header.
3031 <!-- Boolean, Parameterized, Multi-value -->
3033 <para>Parameterized.</para>
3038 <term>Parameter:</term>
3050 The <quote>Content-Type:</quote> HTTP server header is used by the
3051 browser to decide what to do with the document. The value of this
3052 header can cause the browser to open a download menu instead of
3053 displaying the document by itself, even if the document's format is
3054 supported by the browser.
3057 The declared content type can also affect which rendering mode
3058 the browser chooses. If XHTML is delivered as <quote>text/html</quote>,
3059 many browsers treat it as yet another broken HTML document.
3060 If it is send as <quote>application/xml</quote>, browsers with
3061 XHTML support will only display it, if the syntax is correct.
3064 If you see a web site that proudly uses XHTML buttons, but sets
3065 <quote>Content-Type: text/html</quote>, you can use &my-app;
3066 to overwrite it with <quote>application/xml</quote> and validate
3067 the web master's claim inside your XHTML-supporting browser.
3068 If the syntax is incorrect, the browser will complain loudly.
3071 You can also go the opposite direction: if your browser prints
3072 error messages instead of rendering a document falsely declared
3073 as XHTML, you can overwrite the content type with
3074 <quote>text/html</quote> and have it rendered as broken HTML document.
3077 By default <literal>content-type-overwrite</literal> only replaces
3078 <quote>Content-Type:</quote> headers that look like some kind of text.
3079 If you want to overwrite it unconditionally, you have to combine it with
3080 <literal><link linkend="force-text-mode">force-text-mode</link></literal>.
3081 This limitation exists for a reason, think twice before circumventing it.
3084 Most of the time it's easier to replace this action with a custom
3085 <literal><link linkend="server-header-filter">server-header filter</link></literal>.
3086 It allows you to activate it for every document of a certain site and it will still
3087 only replace the content types you aimed at.
3090 Of course you can apply <literal>content-type-overwrite</literal>
3091 to a whole site and then make URL based exceptions, but it's a lot
3092 more work to get the same precision.
3098 <term>Example usage (sections):</term>
3101 <screen># Check if www.example.net/ really uses valid XHTML
3102 { +content-type-overwrite{application/xml} }
3105 # but leave the content type unmodified if the URL looks like a style sheet
3106 {-content-type-overwrite}
3107 www.example.net/.*\.css$
3108 www.example.net/.*style
3117 <!-- ~~~~~ New section ~~~~~ -->
3118 <sect3 renderas="sect4" id="crunch-client-header">
3122 <title>crunch-client-header</title>
3126 <term>Typical use:</term>
3128 <para>Remove a client header <application>Privoxy</application> has no dedicated action for.</para>
3133 <term>Effect:</term>
3136 Deletes every header sent by the client that contains the string the user supplied as parameter.
3143 <!-- Boolean, Parameterized, Multi-value -->
3145 <para>Parameterized.</para>
3150 <term>Parameter:</term>
3162 This action allows you to block client headers for which no dedicated
3163 <application>Privoxy</application> action exists.
3164 <application>Privoxy</application> will remove every client header that
3165 contains the string you supplied as parameter.
3168 Regular expressions are <emphasis>not supported</emphasis> and you can't
3169 use this action to block different headers in the same request, unless
3170 they contain the same string.
3173 <literal>crunch-client-header</literal> is only meant for quick tests.
3174 If you have to block several different headers, or only want to modify
3175 parts of them, you should use a
3176 <literal><link linkend="client-header-filter">client-header filter</link></literal>.
3180 Don't block any header without understanding the consequences.
3187 <term>Example usage (section):</term>
3190 <screen># Block the non-existent "Privacy-Violation:" client header
3191 { +crunch-client-header{Privacy-Violation:} }
3201 <!-- ~~~~~ New section ~~~~~ -->
3202 <sect3 renderas="sect4" id="crunch-if-none-match">
3203 <title>crunch-if-none-match</title>
3209 <term>Typical use:</term>
3211 <para>Prevent yet another way to track the user's steps between sessions.</para>
3216 <term>Effect:</term>
3219 Deletes the <quote>If-None-Match:</quote> HTTP client header.
3226 <!-- Boolean, Parameterized, Multi-value -->
3228 <para>Boolean.</para>
3233 <term>Parameter:</term>
3245 Removing the <quote>If-None-Match:</quote> HTTP client header
3246 is useful for filter testing, where you want to force a real
3247 reload instead of getting status code <quote>304</quote> which
3248 would cause the browser to use a cached copy of the page.
3251 It is also useful to make sure the header isn't used as a cookie
3252 replacement (unlikely but possible).
3255 Blocking the <quote>If-None-Match:</quote> header shouldn't cause any
3256 caching problems, as long as the <quote>If-Modified-Since:</quote> header
3257 isn't blocked or missing as well.
3260 It is recommended to use this action together with
3261 <literal><link linkend="hide-if-modified-since">hide-if-modified-since</link></literal>
3263 <literal><link linkend="overwrite-last-modified">overwrite-last-modified</link></literal>.
3269 <term>Example usage (section):</term>
3272 <screen># Let the browser revalidate cached documents but don't
3273 # allow the server to use the revalidation headers for user tracking.
3274 {+hide-if-modified-since{-60} \
3275 +overwrite-last-modified{randomize} \
3276 +crunch-if-none-match}
3285 <!-- ~~~~~ New section ~~~~~ -->
3286 <sect3 renderas="sect4" id="crunch-incoming-cookies">
3287 <title>crunch-incoming-cookies</title>
3291 <term>Typical use:</term>
3294 Prevent the web server from setting HTTP cookies on your system
3300 <term>Effect:</term>
3303 Deletes any <quote>Set-Cookie:</quote> HTTP headers from server replies.
3310 <!-- Boolean, Parameterized, Multi-value -->
3312 <para>Boolean.</para>
3317 <term>Parameter:</term>
3329 This action is only concerned with <emphasis>incoming</emphasis> HTTP cookies. For
3330 <emphasis>outgoing</emphasis> HTTP cookies, use
3331 <literal><link linkend="crunch-outgoing-cookies">crunch-outgoing-cookies</link></literal>.
3332 Use <emphasis>both</emphasis> to disable HTTP cookies completely.
3335 It makes <emphasis>no sense at all</emphasis> to use this action in conjunction
3336 with the <literal><link linkend="session-cookies-only">session-cookies-only</link></literal> action,
3337 since it would prevent the session cookies from being set. See also
3338 <literal><link linkend="filter-content-cookies">filter-content-cookies</link></literal>.
3344 <term>Example usage:</term>
3347 <screen>+crunch-incoming-cookies</screen>
3355 <!-- ~~~~~ New section ~~~~~ -->
3356 <sect3 renderas="sect4" id="crunch-server-header">
3357 <title>crunch-server-header</title>
3363 <term>Typical use:</term>
3365 <para>Remove a server header <application>Privoxy</application> has no dedicated action for.</para>
3370 <term>Effect:</term>
3373 Deletes every header sent by the server that contains the string the user supplied as parameter.
3380 <!-- Boolean, Parameterized, Multi-value -->
3382 <para>Parameterized.</para>
3387 <term>Parameter:</term>
3399 This action allows you to block server headers for which no dedicated
3400 <application>Privoxy</application> action exists. <application>Privoxy</application>
3401 will remove every server header that contains the string you supplied as parameter.
3404 Regular expressions are <emphasis>not supported</emphasis> and you can't
3405 use this action to block different headers in the same request, unless
3406 they contain the same string.
3409 <literal>crunch-server-header</literal> is only meant for quick tests.
3410 If you have to block several different headers, or only want to modify
3411 parts of them, you should use a custom
3412 <literal><link linkend="server-header-filter">server-header filter</link></literal>.
3416 Don't block any header without understanding the consequences.
3423 <term>Example usage (section):</term>
3426 <screen># Crunch server headers that try to prevent caching
3427 { +crunch-server-header{no-cache} }
3436 <!-- ~~~~~ New section ~~~~~ -->
3437 <sect3 renderas="sect4" id="crunch-outgoing-cookies">
3438 <title>crunch-outgoing-cookies</title>
3442 <term>Typical use:</term>
3445 Prevent the web server from reading any HTTP cookies from your system
3451 <term>Effect:</term>
3454 Deletes any <quote>Cookie:</quote> HTTP headers from client requests.
3461 <!-- Boolean, Parameterized, Multi-value -->
3463 <para>Boolean.</para>
3468 <term>Parameter:</term>
3480 This action is only concerned with <emphasis>outgoing</emphasis> HTTP cookies. For
3481 <emphasis>incoming</emphasis> HTTP cookies, use
3482 <literal><link linkend="crunch-incoming-cookies">crunch-incoming-cookies</link></literal>.
3483 Use <emphasis>both</emphasis> to disable HTTP cookies completely.
3486 It makes <emphasis>no sense at all</emphasis> to use this action in conjunction
3487 with the <literal><link linkend="session-cookies-only">session-cookies-only</link></literal> action,
3488 since it would prevent the session cookies from being read.
3494 <term>Example usage:</term>
3497 <screen>+crunch-outgoing-cookies</screen>
3506 <!-- ~~~~~ New section ~~~~~ -->
3507 <sect3 renderas="sect4" id="deanimate-gifs">
3508 <title>deanimate-gifs</title>
3512 <term>Typical use:</term>
3514 <para>Stop those annoying, distracting animated GIF images.</para>
3519 <term>Effect:</term>
3522 De-animate GIF animations, i.e. reduce them to their first or last image.
3529 <!-- boolean, parameterized, Multi-value -->
3531 <para>Parameterized.</para>
3536 <term>Parameter:</term>
3539 <quote>last</quote> or <quote>first</quote>
3548 This will also shrink the images considerably (in bytes, not pixels!). If
3549 the option <quote>first</quote> is given, the first frame of the animation
3550 is used as the replacement. If <quote>last</quote> is given, the last
3551 frame of the animation is used instead, which probably makes more sense for
3552 most banner animations, but also has the risk of not showing the entire
3553 last frame (if it is only a delta to an earlier frame).
3556 You can safely use this action with patterns that will also match non-GIF
3557 objects, because no attempt will be made at anything that doesn't look like
3564 <term>Example usage:</term>
3567 <screen>+deanimate-gifs{last}</screen>
3574 <!-- ~~~~~ New section ~~~~~ -->
3575 <sect3 renderas="sect4" id="downgrade-http-version">
3576 <title>downgrade-http-version</title>
3580 <term>Typical use:</term>
3582 <para>Work around (very rare) problems with HTTP/1.1</para>
3587 <term>Effect:</term>
3590 Downgrades HTTP/1.1 client requests and server replies to HTTP/1.0.
3597 <!-- boolean, parameterized, Multi-value -->
3599 <para>Boolean.</para>
3604 <term>Parameter:</term>
3616 This is a left-over from the time when <application>Privoxy</application>
3617 didn't support important HTTP/1.1 features well. It is left here for the
3618 unlikely case that you experience HTTP/1.1-related problems with some server
3622 Note that enabling this action is only a workaround. It should not
3623 be enabled for sites that work without it. While it shouldn't break
3624 any pages, it has an (usually negative) performance impact.
3627 If you come across a site where enabling this action helps, please report it,
3628 so the cause of the problem can be analyzed. If the problem turns out to be
3629 caused by a bug in <application>Privoxy</application> it should be
3630 fixed so the following release works without the work around.
3636 <term>Example usage (section):</term>
3639 <screen>{+downgrade-http-version}
3640 problem-host.example.com</screen>
3648 <!-- ~~~~~ New section ~~~~~ -->
3649 <sect3 renderas="sect4" id="fast-redirects">
3650 <title>fast-redirects</title>
3654 <term>Typical use:</term>
3656 <para>Fool some click-tracking scripts and speed up indirect links.</para>
3661 <term>Effect:</term>
3664 Detects redirection URLs and redirects the browser without contacting
3665 the redirection server first.
3672 <!-- boolean, parameterized, Multi-value -->
3674 <para>Parameterized.</para>
3679 <term>Parameter:</term>
3684 <quote>simple-check</quote> to just search for the string <quote>http://</quote>
3685 to detect redirection URLs.
3690 <quote>check-decoded-url</quote> to decode URLs (if necessary) before searching
3691 for redirection URLs.
3702 Many sites, like yahoo.com, don't just link to other sites. Instead, they
3703 will link to some script on their own servers, giving the destination as a
3704 parameter, which will then redirect you to the final target. URLs
3705 resulting from this scheme typically look like:
3706 <quote>http://www.example.org/click-tracker.cgi?target=http%3a//www.example.net/</quote>.
3709 Sometimes, there are even multiple consecutive redirects encoded in the
3710 URL. These redirections via scripts make your web browsing more traceable,
3711 since the server from which you follow such a link can see where you go
3712 to. Apart from that, valuable bandwidth and time is wasted, while your
3713 browser asks the server for one redirect after the other. Plus, it feeds
3717 This feature is currently not very smart and is scheduled for improvement.
3718 If it is enabled by default, you will have to create some exceptions to
3719 this action. It can lead to failures in several ways:
3722 Not every URLs with other URLs as parameters is evil.
3723 Some sites offer a real service that requires this information to work.
3724 For example a validation service needs to know, which document to validate.
3725 <literal>fast-redirects</literal> assumes that every URL parameter that
3726 looks like another URL is a redirection target, and will always redirect to
3727 the last one. Most of the time the assumption is correct, but if it isn't,
3728 the user gets redirected anyway.
3731 Another failure occurs if the URL contains other parameters after the URL parameter.
3733 <quote>http://www.example.org/?redirect=http%3a//www.example.net/&foo=bar</quote>.
3734 contains the redirection URL <quote>http://www.example.net/</quote>,
3735 followed by another parameter. <literal>fast-redirects</literal> doesn't know that
3736 and will cause a redirect to <quote>http://www.example.net/&foo=bar</quote>.
3737 Depending on the target server configuration, the parameter will be silently ignored
3738 or lead to a <quote>page not found</quote> error. You can prevent this problem by
3739 first using the <literal><link linkend="redirect">redirect</link></literal> action
3740 to remove the last part of the URL, but it requires a little effort.
3743 To detect a redirection URL, <literal>fast-redirects</literal> only
3744 looks for the string <quote>http://</quote>, either in plain text
3745 (invalid but often used) or encoded as <quote>http%3a//</quote>.
3746 Some sites use their own URL encoding scheme, encrypt the address
3747 of the target server or replace it with a database id. In theses cases
3748 <literal>fast-redirects</literal> is fooled and the request reaches the
3749 redirection server where it probably gets logged.
3755 <term>Example usage:</term>
3759 { +fast-redirects{simple-check} }
3762 { +fast-redirects{check-decoded-url} }
3763 another.example.com/testing</screen>
3772 <!-- ~~~~~ New section ~~~~~ -->
3773 <sect3 renderas="sect4" id="filter">
3774 <title>filter</title>
3778 <term>Typical use:</term>
3780 <para>Get rid of HTML and JavaScript annoyances, banner advertisements (by size),
3781 do fun text replacements, add personalized effects, etc.</para>
3786 <term>Effect:</term>
3789 All instances of text-based type, most notably HTML and JavaScript, to which
3790 this action applies, can be filtered on-the-fly through the specified regular
3791 expression based substitutions. (Note: as of version 3.0.3 plain text documents
3792 are exempted from filtering, because web servers often use the
3793 <literal>text/plain</literal> MIME type for all files whose type they don't know.)
3800 <!-- boolean, parameterized, Multi-value -->
3802 <para>Parameterized.</para>
3807 <term>Parameter:</term>
3810 The name of a content filter, as defined in the <link linkend="filter-file">filter file</link>.
3811 Filters can be defined in one or more files as defined by the
3812 <literal><link linkend="filterfile">filterfile</link></literal>
3813 option in the <link linkend="config">config file</link>.
3814 <filename>default.filter</filename> is the collection of filters
3815 supplied by the developers. Locally defined filters should go
3816 in their own file, such as <filename>user.filter</filename>.
3819 When used in its negative form,
3820 and without parameters, <emphasis>all</emphasis> filtering is completely disabled.
3829 For your convenience, there are a number of pre-defined filters available
3830 in the distribution filter file that you can use. See the examples below for
3834 Filtering requires buffering the page content, which may appear to
3835 slow down page rendering since nothing is displayed until all content has
3836 passed the filters. (The total time until the page is completely rendered
3837 doesn't change much, but it may be perceived as slower since the page is
3838 not incrementally displayed.)
3839 This effect will be more noticeable on slower connections.
3842 <quote>Rolling your own</quote>
3843 filters requires a knowledge of
3844 <ulink url="http://en.wikipedia.org/wiki/Regular_expressions"><quote>Regular
3845 Expressions</quote></ulink> and
3846 <ulink url="http://en.wikipedia.org/wiki/Html"><quote>HTML</quote></ulink>.
3847 This is very powerful feature, and potentially very intrusive.
3848 Filters should be used with caution, and where an equivalent
3849 <quote>action</quote> is not available.
3852 The amount of data that can be filtered is limited to the
3853 <literal><link linkend="buffer-limit">buffer-limit</link></literal>
3854 option in the main <link linkend="config">config file</link>. The
3855 default is 4096 KB (4 Megs). Once this limit is exceeded, the buffered
3856 data, and all pending data, is passed through unfiltered.
3859 Inappropriate MIME types, such as zipped files, are not filtered at all.
3860 (Again, only text-based types except plain text). Encrypted SSL data
3861 (from HTTPS servers) cannot be filtered either, since this would violate
3862 the integrity of the secure transaction. In some situations it might
3863 be necessary to protect certain text, like source code, from filtering
3864 by defining appropriate <literal>-filter</literal> exceptions.
3867 Compressed content can't be filtered either, but if &my-app;
3868 is compiled with zlib support and a supported compression algorithm
3869 is used (gzip or deflate), &my-app; can first decompress the content
3873 If you use a &my-app; version without zlib support, but want filtering to work on
3874 as much documents as possible, even those that would normally be sent compressed,
3875 you must use the <literal><link linkend="prevent-compression">prevent-compression</link></literal>
3876 action in conjunction with <literal>filter</literal>.
3879 Content filtering can achieve some of the same effects as the
3880 <literal><link linkend="block">block</link></literal>
3881 action, i.e. it can be used to block ads and banners. But the mechanism
3882 works quite differently. One effective use, is to block ad banners
3883 based on their size (see below), since many of these seem to be somewhat
3887 <link linkend="contact">Feedback</link> with suggestions for new or
3888 improved filters is particularly welcome!
3891 The below list has only the names and a one-line description of each
3892 predefined filter. There are <link linkend="predefined-filters">more
3893 verbose explanations</link> of what these filters do in the <link
3894 linkend="filter-file">filter file chapter</link>.
3900 <term>Example usage (with filters from the distribution <filename>default.filter</filename> file).
3901 See <link linkend="PREDEFINED-FILTERS">the Predefined Filters section</link> for
3902 more explanation on each:</term>
3905 <anchor id="filter-js-annoyances">
3906 <screen>+filter{js-annoyances} # Get rid of particularly annoying JavaScript abuse.</screen>
3909 <anchor id="filter-js-events">
3910 <screen>+filter{js-events} # Kill all JS event bindings and timers (Radically destructive! Only for extra nasty sites).</screen>
3913 <anchor id="filter-html-annoyances">
3914 <screen>+filter{html-annoyances} # Get rid of particularly annoying HTML abuse.</screen>
3917 <anchor id="filter-content-cookies">
3918 <screen>+filter{content-cookies} # Kill cookies that come in the HTML or JS content.</screen>
3921 <anchor id="filter-refresh-tags">
3922 <screen>+filter{refresh-tags} # Kill automatic refresh tags (for dial-on-demand setups).</screen>
3925 <anchor id="filter-unsolicited-popups">
3926 <screen>+filter{unsolicited-popups} # Disable only unsolicited pop-up windows. Useful if your browser lacks this ability.</screen>
3929 <anchor id="filter-all-popups">
3930 <screen>+filter{all-popups} # Kill all popups in JavaScript and HTML. Useful if your browser lacks this ability.</screen>
3933 <anchor id="filter-img-reorder">
3934 <screen>+filter{img-reorder} # Reorder attributes in <img> tags to make the banners-by-* filters more effective.</screen>
3937 <anchor id="filter-banners-by-size">
3938 <screen>+filter{banners-by-size} # Kill banners by size.</screen>
3941 <anchor id="filter-banners-by-link">
3942 <screen>+filter{banners-by-link} # Kill banners by their links to known clicktrackers.</screen>
3945 <anchor id="filter-webbugs">
3946 <screen>+filter{webbugs} # Squish WebBugs (1x1 invisible GIFs used for user tracking).</screen>
3949 <anchor id="filter-tiny-textforms">
3950 <screen>+filter{tiny-textforms} # Extend those tiny textareas up to 40x80 and kill the hard wrap.</screen>
3953 <anchor id="filter-jumping-windows">
3954 <screen>+filter{jumping-windows} # Prevent windows from resizing and moving themselves.</screen>
3957 <anchor id="filter-frameset-borders">
3958 <screen>+filter{frameset-borders} # Give frames a border and make them resizable.</screen>
3961 <anchor id="filter-demoronizer">
3962 <screen>+filter{demoronizer} # Fix MS's non-standard use of standard charsets.</screen>
3965 <anchor id="filter-shockwave-flash">
3966 <screen>+filter{shockwave-flash} # Kill embedded Shockwave Flash objects.</screen>
3969 <anchor id="filter-quicktime-kioskmode">
3970 <screen>+filter{quicktime-kioskmode} # Make Quicktime movies saveable.</screen>
3973 <anchor id="filter-fun">
3974 <screen>+filter{fun} # Text replacements for subversive browsing fun!</screen>
3977 <anchor id="filter-crude-parental">
3978 <screen>+filter{crude-parental} # Crude parental filtering. Note that this filter doesn't work reliably.</screen>
3981 <anchor id="filter-ie-exploits">
3982 <screen>+filter{ie-exploits} # Disable some known Internet Explorer bug exploits.</screen>
3985 <anchor id="filter-site-specifics">
3986 <screen>+filter{site-specifics} # Cure for site-specific problems. Don't apply generally!</screen>
3989 <anchor id="filter-no-ping">
3990 <screen>+filter{no-ping} # Removes non-standard ping attributes in <a> and <area> tags.</screen>
3993 <anchor id="filter-google">
3994 <screen>+filter{google} # CSS-based block for Google text ads. Also removes a width limitation and the toolbar advertisement.</screen>
3997 <anchor id="filter-yahoo">
3998 <screen>+filter{yahoo} # CSS-based block for Yahoo text ads. Also removes a width limitation.</screen>
4001 <anchor id="filter-msn">
4002 <screen>+filter{msn} # CSS-based block for MSN text ads. Also removes tracking URLs and a width limitation.</screen>
4005 <anchor id="filter-blogspot">
4006 <screen>+filter{blogspot} # Cleans up some Blogspot blogs. Read the fine print before using this.</screen>
4014 <!-- ~~~~~ New section ~~~~~ -->
4015 <sect3 renderas="sect4" id="force-text-mode">
4016 <title>force-text-mode</title>
4022 <term>Typical use:</term>
4024 <para>Force <application>Privoxy</application> to treat a document as if it was in some kind of <emphasis>text</emphasis> format. </para>
4029 <term>Effect:</term>
4032 Declares a document as text, even if the <quote>Content-Type:</quote> isn't detected as such.
4039 <!-- Boolean, Parameterized, Multi-value -->
4041 <para>Boolean.</para>
4046 <term>Parameter:</term>
4058 As explained <literal><link linkend="filter">above</link></literal>,
4059 <application>Privoxy</application> tries to only filter files that are
4060 in some kind of text format. The same restrictions apply to
4061 <literal><link linkend="content-type-overwrite">content-type-overwrite</link></literal>.
4062 <literal>force-text-mode</literal> declares a document as text,
4063 without looking at the <quote>Content-Type:</quote> first.
4067 Think twice before activating this action. Filtering binary data
4068 with regular expressions can cause file damage.
4075 <term>Example usage:</term>
4088 <!-- ~~~~~ New section ~~~~~ -->
4089 <sect3 renderas="sect4" id="forward-override">
4090 <title>forward-override</title>
4096 <term>Typical use:</term>
4098 <para>Change the forwarding settings based on User-Agent or request origin</para>
4103 <term>Effect:</term>
4106 Overrules the forward directives in the configuration file.
4113 <!-- Boolean, Parameterized, Multi-value -->
4115 <para>Multi-value.</para>
4120 <term>Parameter:</term>
4124 <para><quote>forward .</quote> to use a direct connection without any additional proxies.</para>
4128 <quote>forward 127.0.0.1:8123</quote> to use the HTTP proxy listening at 127.0.0.1 port 8123.
4133 <quote>forward-socks4a 127.0.0.1:9050 .</quote> to use the socks4a proxy listening at
4134 127.0.0.1 port 9050. Replace <quote>forward-socks4a</quote> with <quote>forward-socks4</quote>
4135 to use a socks4 connection (with local DNS resolution) instead, use <quote>forward-socks5</quote>
4136 for socks5 connections (with remote DNS resolution).
4141 <quote>forward-socks4a 127.0.0.1:9050 proxy.example.org:8000</quote> to use the socks4a proxy
4142 listening at 127.0.0.1 port 9050 to reach the HTTP proxy listening at proxy.example.org port 8000.
4143 Replace <quote>forward-socks4a</quote> with <quote>forward-socks4</quote> to use a socks4 connection
4144 (with local DNS resolution) instead, use <quote>forward-socks5</quote>
4145 for socks5 connections (with remote DNS resolution).
4156 This action takes parameters similar to the
4157 <link linkend="forwarding">forward</link> directives in the configuration
4158 file, but without the URL pattern. It can be used as replacement, but normally it's only
4159 used in cases where matching based on the request URL isn't sufficient.
4163 Please read the description for the <link linkend="forwarding">forward</link> directives before
4164 using this action. Forwarding to the wrong people will reduce your privacy and increase the
4165 chances of man-in-the-middle attacks.
4168 If the ports are missing or invalid, default values will be used. This might change
4169 in the future and you shouldn't rely on it. Otherwise incorrect syntax causes Privoxy
4173 Use the <ulink url="http://config.privoxy.org/show-url-info">show-url-info CGI page</ulink>
4174 to verify that your forward settings do what you thought the do.
4181 <term>Example usage:</term>
4185 # Always use direct connections for requests previously tagged as
4186 # <quote>User-Agent: fetch libfetch/2.0</quote> and make sure
4187 # resuming downloads continues to work.
4188 # This way you can continue to use Tor for your normal browsing,
4189 # without overloading the Tor network with your FreeBSD ports updates
4190 # or downloads of bigger files like ISOs.
4191 # Note that HTTP headers are easy to fake and therefore their
4192 # values are as (un)trustworthy as your clients and users.
4193 {+forward-override{forward .} \
4194 -hide-if-modified-since \
4195 -overwrite-last-modified \
4197 TAG:^User-Agent: fetch libfetch/2\.0$
4206 <!-- ~~~~~ New section ~~~~~ -->
4207 <sect3 renderas="sect4" id="handle-as-empty-document">
4208 <title>handle-as-empty-document</title>
4214 <term>Typical use:</term>
4216 <para>Mark URLs that should be replaced by empty documents <emphasis>if they get blocked</emphasis></para>
4221 <term>Effect:</term>
4224 This action alone doesn't do anything noticeable. It just marks URLs.
4225 If the <literal><link linkend="block">block</link></literal> action <emphasis>also applies</emphasis>,
4226 the presence or absence of this mark decides whether an HTML <quote>BLOCKED</quote>
4227 page, or an empty document will be sent to the client as a substitute for the blocked content.
4228 The <emphasis>empty</emphasis> document isn't literally empty, but actually contains a single space.
4235 <!-- Boolean, Parameterized, Multi-value -->
4237 <para>Boolean.</para>
4242 <term>Parameter:</term>
4254 Some browsers complain about syntax errors if JavaScript documents
4255 are blocked with <application>Privoxy's</application>
4256 default HTML page; this option can be used to silence them.
4257 And of course this action can also be used to eliminate the &my-app;
4258 BLOCKED message in frames.
4261 The content type for the empty document can be specified with
4262 <literal><link linkend="content-type-overwrite">content-type-overwrite{}</link></literal>,
4263 but usually this isn't necessary.
4269 <term>Example usage:</term>
4272 <screen># Block all documents on example.org that end with ".js",
4273 # but send an empty document instead of the usual HTML message.
4274 {+block{Blocked JavaScript} +handle-as-empty-document}
4284 <!-- ~~~~~ New section ~~~~~ -->
4285 <sect3 renderas="sect4" id="handle-as-image">
4286 <title>handle-as-image</title>
4290 <term>Typical use:</term>
4292 <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>
4297 <term>Effect:</term>
4300 This action alone doesn't do anything noticeable. It just marks URLs as images.
4301 If the <literal><link linkend="block">block</link></literal> action <emphasis>also applies</emphasis>,
4302 the presence or absence of this mark decides whether an HTML <quote>blocked</quote>
4303 page, or a replacement image (as determined by the <literal><link
4304 linkend="set-image-blocker">set-image-blocker</link></literal> action) will be sent to the
4305 client as a substitute for the blocked content.
4312 <!-- Boolean, Parameterized, Multi-value -->
4314 <para>Boolean.</para>
4319 <term>Parameter:</term>
4331 The below generic example section is actually part of <filename>default.action</filename>.
4332 It marks all URLs with well-known image file name extensions as images and should
4336 Users will probably only want to use the handle-as-image action in conjunction with
4337 <literal><link linkend="block">block</link></literal>, to block sources of banners, whose URLs don't
4338 reflect the file type, like in the second example section.
4341 Note that you cannot treat HTML pages as images in most cases. For instance, (in-line) ad
4342 frames require an HTML page to be sent, or they won't display properly.
4343 Forcing <literal>handle-as-image</literal> in this situation will not replace the
4344 ad frame with an image, but lead to error messages.
4350 <term>Example usage (sections):</term>
4353 <screen># Generic image extensions:
4356 /.*\.(gif|jpg|jpeg|png|bmp|ico)$
4358 # These don't look like images, but they're banners and should be
4359 # blocked as images:
4361 {+block{Nasty banners.} +handle-as-image}
4362 nasty-banner-server.example.com/junk.cgi\?output=trash
4371 <!-- ~~~~~ New section ~~~~~ -->
4372 <sect3 renderas="sect4" id="hide-accept-language">
4373 <title>hide-accept-language</title>
4379 <term>Typical use:</term>
4381 <para>Pretend to use different language settings.</para>
4386 <term>Effect:</term>
4389 Deletes or replaces the <quote>Accept-Language:</quote> HTTP header in client requests.
4396 <!-- Boolean, Parameterized, Multi-value -->
4398 <para>Parameterized.</para>
4403 <term>Parameter:</term>
4406 Keyword: <quote>block</quote>, or any user defined value.
4415 Faking the browser's language settings can be useful to make a
4416 foreign User-Agent set with
4417 <literal><link linkend="hide-user-agent">hide-user-agent</link></literal>
4421 However some sites with content in different languages check the
4422 <quote>Accept-Language:</quote> to decide which one to take by default.
4423 Sometimes it isn't possible to later switch to another language without
4424 changing the <quote>Accept-Language:</quote> header first.
4427 Therefore it's a good idea to either only change the
4428 <quote>Accept-Language:</quote> header to languages you understand,
4429 or to languages that aren't wide spread.
4432 Before setting the <quote>Accept-Language:</quote> header
4433 to a rare language, you should consider that it helps to
4434 make your requests unique and thus easier to trace.
4435 If you don't plan to change this header frequently,
4436 you should stick to a common language.
4442 <term>Example usage (section):</term>
4445 <screen># Pretend to use Canadian language settings.
4446 {+hide-accept-language{en-ca} \
4447 +hide-user-agent{Mozilla/5.0 (X11; U; OpenBSD i386; en-CA; rv:1.8.0.4) Gecko/20060628 Firefox/1.5.0.4} \
4457 <!-- ~~~~~ New section ~~~~~ -->
4458 <sect3 renderas="sect4" id="hide-content-disposition">
4459 <title>hide-content-disposition</title>
4465 <term>Typical use:</term>
4467 <para>Prevent download menus for content you prefer to view inside the browser.</para>
4472 <term>Effect:</term>
4475 Deletes or replaces the <quote>Content-Disposition:</quote> HTTP header set by some servers.
4482 <!-- Boolean, Parameterized, Multi-value -->
4484 <para>Parameterized.</para>
4489 <term>Parameter:</term>
4492 Keyword: <quote>block</quote>, or any user defined value.
4501 Some servers set the <quote>Content-Disposition:</quote> HTTP header for
4502 documents they assume you want to save locally before viewing them.
4503 The <quote>Content-Disposition:</quote> header contains the file name
4504 the browser is supposed to use by default.
4507 In most browsers that understand this header, it makes it impossible to
4508 <emphasis>just view</emphasis> the document, without downloading it first,
4509 even if it's just a simple text file or an image.
4512 Removing the <quote>Content-Disposition:</quote> header helps
4513 to prevent this annoyance, but some browsers additionally check the
4514 <quote>Content-Type:</quote> header, before they decide if they can
4515 display a document without saving it first. In these cases, you have
4516 to change this header as well, before the browser stops displaying
4520 It is also possible to change the server's file name suggestion
4521 to another one, but in most cases it isn't worth the time to set
4525 This action will probably be removed in the future,
4526 use server-header filters instead.
4532 <term>Example usage:</term>
4535 <screen># Disarm the download link in Sourceforge's patch tracker
4537 +content-type-overwrite{text/plain}\
4538 +hide-content-disposition{block} }
4539 .sourceforge.net/tracker/download\.php</screen>
4547 <!-- ~~~~~ New section ~~~~~ -->
4548 <sect3 renderas="sect4" id="hide-if-modified-since">
4549 <title>hide-if-modified-since</title>
4555 <term>Typical use:</term>
4557 <para>Prevent yet another way to track the user's steps between sessions.</para>
4562 <term>Effect:</term>
4565 Deletes the <quote>If-Modified-Since:</quote> HTTP client header or modifies its value.
4572 <!-- Boolean, Parameterized, Multi-value -->
4574 <para>Parameterized.</para>
4579 <term>Parameter:</term>
4582 Keyword: <quote>block</quote>, or a user defined value that specifies a range of hours.
4591 Removing this header is useful for filter testing, where you want to force a real
4592 reload instead of getting status code <quote>304</quote>, which would cause the
4593 browser to use a cached copy of the page.
4596 Instead of removing the header, <literal>hide-if-modified-since</literal> can
4597 also add or subtract a random amount of time to/from the header's value.
4598 You specify a range of minutes where the random factor should be chosen from and
4599 <application>Privoxy</application> does the rest. A negative value means
4600 subtracting, a positive value adding.
4603 Randomizing the value of the <quote>If-Modified-Since:</quote> makes
4604 it less likely that the server can use the time as a cookie replacement,
4605 but you will run into caching problems if the random range is too high.
4608 It is a good idea to only use a small negative value and let
4609 <literal><link linkend="overwrite-last-modified">overwrite-last-modified</link></literal>
4610 handle the greater changes.
4613 It is also recommended to use this action together with
4614 <literal><link linkend="crunch-if-none-match">crunch-if-none-match</link></literal>,
4615 otherwise it's more or less pointless.
4621 <term>Example usage (section):</term>
4624 <screen># Let the browser revalidate but make tracking based on the time less likely.
4625 {+hide-if-modified-since{-60} \
4626 +overwrite-last-modified{randomize} \
4627 +crunch-if-none-match}
4636 <!-- ~~~~~ New section ~~~~~ -->
4637 <sect3 renderas="sect4" id="hide-from-header">
4638 <title>hide-from-header</title>
4642 <term>Typical use:</term>
4644 <para>Keep your (old and ill) browser from telling web servers your email address</para>
4649 <term>Effect:</term>
4652 Deletes any existing <quote>From:</quote> HTTP header, or replaces it with the
4660 <!-- Boolean, Parameterized, Multi-value -->
4662 <para>Parameterized.</para>
4667 <term>Parameter:</term>
4670 Keyword: <quote>block</quote>, or any user defined value.
4679 The keyword <quote>block</quote> will completely remove the header
4680 (not to be confused with the <literal><link linkend="block">block</link></literal>
4684 Alternately, you can specify any value you prefer to be sent to the web
4685 server. If you do, it is a matter of fairness not to use any address that
4686 is actually used by a real person.
4689 This action is rarely needed, as modern web browsers don't send
4690 <quote>From:</quote> headers anymore.
4696 <term>Example usage:</term>
4699 <screen>+hide-from-header{block}</screen> or
4700 <screen>+hide-from-header{spam-me-senseless@sittingduck.example.com}</screen>
4708 <!-- ~~~~~ New section ~~~~~ -->
4709 <sect3 renderas="sect4" id="hide-referrer">
4710 <title>hide-referrer</title>
4711 <anchor id="hide-referer">
4714 <term>Typical use:</term>
4716 <para>Conceal which link you followed to get to a particular site</para>
4721 <term>Effect:</term>
4724 Deletes the <quote>Referer:</quote> (sic) HTTP header from the client request,
4725 or replaces it with a forged one.
4732 <!-- Boolean, Parameterized, Multi-value -->
4734 <para>Parameterized.</para>
4739 <term>Parameter:</term>
4743 <para><quote>conditional-block</quote> to delete the header completely if the host has changed.</para>
4746 <para><quote>conditional-forge</quote> to forge the header if the host has changed.</para>
4749 <para><quote>block</quote> to delete the header unconditionally.</para>
4752 <para><quote>forge</quote> to pretend to be coming from the homepage of the server we are talking to.</para>
4755 <para>Any other string to set a user defined referrer.</para>
4765 <literal>conditional-block</literal> is the only parameter,
4766 that isn't easily detected in the server's log file. If it blocks the
4767 referrer, the request will look like the visitor used a bookmark or
4768 typed in the address directly.
4771 Leaving the referrer unmodified for requests on the same host
4772 allows the server owner to see the visitor's <quote>click path</quote>,
4773 but in most cases she could also get that information by comparing
4774 other parts of the log file: for example the User-Agent if it isn't
4775 a very common one, or the user's IP address if it doesn't change between
4779 Always blocking the referrer, or using a custom one, can lead to
4780 failures on servers that check the referrer before they answer any
4781 requests, in an attempt to prevent their content from being
4782 embedded or linked to elsewhere.
4785 Both <literal>conditional-block</literal> and <literal>forge</literal>
4786 will work with referrer checks, as long as content and valid referring page
4787 are on the same host. Most of the time that's the case.
4790 <literal>hide-referer</literal> is an alternate spelling of
4791 <literal>hide-referrer</literal> and the two can be can be freely
4792 substituted with each other. (<quote>referrer</quote> is the
4793 correct English spelling, however the HTTP specification has a bug - it
4794 requires it to be spelled as <quote>referer</quote>.)
4800 <term>Example usage:</term>
4803 <screen>+hide-referrer{forge}</screen> or
4804 <screen>+hide-referrer{http://www.yahoo.com/}</screen>
4812 <!-- ~~~~~ New section ~~~~~ -->
4813 <sect3 renderas="sect4" id="hide-user-agent">
4814 <title>hide-user-agent</title>
4818 <term>Typical use:</term>
4820 <para>Try to conceal your type of browser and client operating system</para>
4825 <term>Effect:</term>
4828 Replaces the value of the <quote>User-Agent:</quote> HTTP header
4829 in client requests with the specified value.
4836 <!-- Boolean, Parameterized, Multi-value -->
4838 <para>Parameterized.</para>
4843 <term>Parameter:</term>
4846 Any user-defined string.
4856 This can lead to problems on web sites that depend on looking at this header in
4857 order to customize their content for different browsers (which, by the
4858 way, is <emphasis>NOT</emphasis> the right thing to do: good web sites
4859 work browser-independently).
4863 Using this action in multi-user setups or wherever different types of
4864 browsers will access the same <application>Privoxy</application> is
4865 <emphasis>not recommended</emphasis>. In single-user, single-browser
4866 setups, you might use it to delete your OS version information from
4867 the headers, because it is an invitation to exploit known bugs for your
4868 OS. It is also occasionally useful to forge this in order to access
4869 sites that won't let you in otherwise (though there may be a good
4870 reason in some cases).
4873 More information on known user-agent strings can be found at
4874 <ulink url="http://www.user-agents.org/">http://www.user-agents.org/</ulink>
4876 <ulink url="http://en.wikipedia.org/wiki/User_agent">http://en.wikipedia.org/wiki/User_agent</ulink>.
4882 <term>Example usage:</term>
4885 <screen>+hide-user-agent{Netscape 6.1 (X11; I; Linux 2.4.18 i686)}</screen>
4893 <!-- ~~~~~ New section ~~~~~ -->
4894 <sect3 renderas="sect4" id="limit-connect">
4895 <title>limit-connect</title>
4899 <term>Typical use:</term>
4901 <para>Prevent abuse of <application>Privoxy</application> as a TCP proxy relay or disable SSL for untrusted sites</para>
4906 <term>Effect:</term>
4909 Specifies to which ports HTTP CONNECT requests are allowable.
4916 <!-- Boolean, Parameterized, Multi-value -->
4918 <para>Parameterized.</para>
4923 <term>Parameter:</term>
4926 A comma-separated list of ports or port ranges (the latter using dashes, with the minimum
4927 defaulting to 0 and the maximum to 65K).
4936 By default, i.e. if no <literal>limit-connect</literal> action applies,
4937 <application>Privoxy</application> allows HTTP CONNECT requests to all
4938 ports. Use <literal>limit-connect</literal> if fine-grained control
4939 is desired for some or all destinations.
4942 The CONNECT methods exists in HTTP to allow access to secure websites
4943 (<quote>https://</quote> URLs) through proxies. It works very simply:
4944 the proxy connects to the server on the specified port, and then
4945 short-circuits its connections to the client and to the remote server.
4946 This means CONNECT-enabled proxies can be used as TCP relays very easily.
4949 <application>Privoxy</application> relays HTTPS traffic without seeing
4950 the decoded content. Websites can leverage this limitation to circumvent &my-app;'s
4951 filters. By specifying an invalid port range you can disable HTTPS entirely.
4957 <term>Example usages:</term>
4959 <!-- I had trouble getting the spacing to look right in my browser -->
4960 <!-- I probably have the wrong font setup, bollocks. -->
4961 <!-- Apparently the emphasis tag uses a proportional font no matter what -->
4963 <screen>+limit-connect{443} # Port 443 is OK.
4964 +limit-connect{80,443} # Ports 80 and 443 are OK.
4965 +limit-connect{-3, 7, 20-100, 500-} # Ports less than 3, 7, 20 to 100 and above 500 are OK.
4966 +limit-connect{-} # All ports are OK
4967 +limit-connect{,} # No HTTPS/SSL traffic is allowed</screen>
4975 <!-- ~~~~~ New section ~~~~~ -->
4976 <sect3 renderas="sect4" id="limit-cookie-lifetime">
4977 <title>limit-cookie-lifetime</title>
4981 <term>Typical use:</term>
4983 <para>Limit the lifetime of HTTP cookies to a couple of minutes or hours.</para>
4988 <term>Effect:</term>
4991 Overwrites the expires field in Set-Cookie server headers if it's above the specified limit.
4998 <!-- Boolean, Parameterized, Multi-value -->
5000 <para>Parameterized.</para>
5005 <term>Parameter:</term>
5008 The lifetime limit in minutes, or 0.
5017 This action reduces the lifetime of HTTP cookies coming from the
5018 server to the specified number of minutes, starting from the time
5019 the cookie passes Privoxy.
5022 Cookies with a lifetime below the limit are not modified.
5023 The lifetime of session cookies is set to the specified limit.
5026 The effect of this action depends on the server.
5029 In case of servers which refresh their cookies with each response
5030 (or at least frequently), the lifetime limit set by this action
5032 Thus, a session associated with the cookie continues to work with
5033 this action enabled, as long as a new request is made before the
5034 last limit set is reached.
5037 However, some servers send their cookies once, with a lifetime of several
5038 years (the year 2037 is a popular choice), and do not refresh them
5039 until a certain event in the future, for example the user logging out.
5040 In this case this action may limit the absolute lifetime of the session,
5041 even if requests are made frequently.
5044 If the parameter is <quote>0</quote>, this action behaves like
5045 <literal><link linkend="session-cookies-only">session-cookies-only</link></literal>.
5051 <term>Example usages:</term>
5054 <screen>+limit-cookie-lifetime{60}
5062 <!-- ~~~~~ New section ~~~~~ -->
5063 <sect3 renderas="sect4" id="prevent-compression">
5064 <title>prevent-compression</title>
5068 <term>Typical use:</term>
5071 Ensure that servers send the content uncompressed, so it can be
5072 passed through <literal><link linkend="filter">filter</link></literal>s.
5078 <term>Effect:</term>
5081 Removes the Accept-Encoding header which can be used to ask for compressed transfer.
5088 <!-- Boolean, Parameterized, Multi-value -->
5090 <para>Boolean.</para>
5095 <term>Parameter:</term>
5107 More and more websites send their content compressed by default, which
5108 is generally a good idea and saves bandwidth. But the <literal><link
5109 linkend="filter">filter</link></literal> and
5110 <literal><link linkend="deanimate-gifs">deanimate-gifs</link></literal>
5111 actions need access to the uncompressed data.
5114 When compiled with zlib support (available since &my-app; 3.0.7), content that should be
5115 filtered is decompressed on-the-fly and you don't have to worry about this action.
5116 If you are using an older &my-app; version, or one that hasn't been compiled with zlib
5117 support, this action can be used to convince the server to send the content uncompressed.
5120 Most text-based instances compress very well, the size is seldom decreased by less than 50%,
5121 for markup-heavy instances like news feeds saving more than 90% of the original size isn't
5125 Not using compression will therefore slow down the transfer, and you should only
5126 enable this action if you really need it. As of &my-app; 3.0.7 it's disabled in all
5127 predefined action settings.
5130 Note that some (rare) ill-configured sites don't handle requests for uncompressed
5131 documents correctly. Broken PHP applications tend to send an empty document body,
5132 some IIS versions only send the beginning of the content. If you enable
5133 <literal>prevent-compression</literal> per default, you might want to add
5134 exceptions for those sites. See the example for how to do that.
5140 <term>Example usage (sections):</term>
5144 # Selectively turn off compression, and enable a filter
5146 { +filter{tiny-textforms} +prevent-compression }
5147 # Match only these sites
5152 # Or instead, we could set a universal default:
5154 { +prevent-compression }
5157 # Then maybe make exceptions for broken sites:
5159 { -prevent-compression }
5160 .compusa.com/</screen>
5169 <!-- ~~~~~ New section ~~~~~ -->
5170 <sect3 renderas="sect4" id="overwrite-last-modified">
5171 <title>overwrite-last-modified</title>
5177 <term>Typical use:</term>
5179 <para>Prevent yet another way to track the user's steps between sessions.</para>
5184 <term>Effect:</term>
5187 Deletes the <quote>Last-Modified:</quote> HTTP server header or modifies its value.
5194 <!-- Boolean, Parameterized, Multi-value -->
5196 <para>Parameterized.</para>
5201 <term>Parameter:</term>
5204 One of the keywords: <quote>block</quote>, <quote>reset-to-request-time</quote>
5205 and <quote>randomize</quote>
5214 Removing the <quote>Last-Modified:</quote> header is useful for filter
5215 testing, where you want to force a real reload instead of getting status
5216 code <quote>304</quote>, which would cause the browser to reuse the old
5217 version of the page.
5220 The <quote>randomize</quote> option overwrites the value of the
5221 <quote>Last-Modified:</quote> header with a randomly chosen time
5222 between the original value and the current time. In theory the server
5223 could send each document with a different <quote>Last-Modified:</quote>
5224 header to track visits without using cookies. <quote>Randomize</quote>
5225 makes it impossible and the browser can still revalidate cached documents.
5228 <quote>reset-to-request-time</quote> overwrites the value of the
5229 <quote>Last-Modified:</quote> header with the current time. You could use
5230 this option together with
5231 <literal><link linkend="hide-if-modified-since">hide-if-modified-since</link></literal>
5232 to further customize your random range.
5235 The preferred parameter here is <quote>randomize</quote>. It is safe
5236 to use, as long as the time settings are more or less correct.
5237 If the server sets the <quote>Last-Modified:</quote> header to the time
5238 of the request, the random range becomes zero and the value stays the same.
5239 Therefore you should later randomize it a second time with
5240 <literal><link linkend="hide-if-modified-since">hided-if-modified-since</link></literal>,
5244 It is also recommended to use this action together with
5245 <literal><link linkend="crunch-if-none-match">crunch-if-none-match</link></literal>.
5251 <term>Example usage:</term>
5254 <screen># Let the browser revalidate without being tracked across sessions
5255 { +hide-if-modified-since{-60} \
5256 +overwrite-last-modified{randomize} \
5257 +crunch-if-none-match}
5266 <!-- ~~~~~ New section ~~~~~ -->
5267 <sect3 renderas="sect4" id="redirect">
5268 <title>redirect</title>
5274 <term>Typical use:</term>
5277 Redirect requests to other sites.
5283 <term>Effect:</term>
5286 Convinces the browser that the requested document has been moved
5287 to another location and the browser should get it from there.
5294 <!-- Boolean, Parameterized, Multi-value -->
5296 <para>Parameterized</para>
5301 <term>Parameter:</term>
5304 An absolute URL or a single pcrs command.
5313 Requests to which this action applies are answered with a
5314 HTTP redirect to URLs of your choosing. The new URL is
5315 either provided as parameter, or derived by applying a
5316 single pcrs command to the original URL.
5319 The syntax for pcrs commands is documented in the
5320 <link linkend="filter-file">filter file</link> section.
5323 This action will be ignored if you use it together with
5324 <literal><link linkend="block">block</link></literal>.
5325 It can be combined with
5326 <literal><link linkend="fast-redirects">fast-redirects{check-decoded-url}</link></literal>
5327 to redirect to a decoded version of a rewritten URL.
5330 Use this action carefully, make sure not to create redirection loops
5331 and be aware that using your own redirects might make it
5332 possible to fingerprint your requests.
5335 In case of problems with your redirects, or simply to watch
5336 them working, enable <link linkend="DEBUG">debug 128</link>.
5342 <term>Example usages:</term>
5345 <screen># Replace example.com's style sheet with another one
5346 { +redirect{http://localhost/css-replacements/example.com.css} }
5347 example.com/stylesheet\.css
5349 # Create a short, easy to remember nickname for a favorite site
5350 # (relies on the browser accept and forward invalid URLs to &my-app;)
5351 { +redirect{http://www.privoxy.org/user-manual/actions-file.html} }
5354 # Always use the expanded view for Undeadly.org articles
5355 # (Note the $ at the end of the URL pattern to make sure
5356 # the request for the rewritten URL isn't redirected as well)
5357 {+redirect{s@$@&mode=expanded@}}
5358 undeadly.org/cgi\?action=article&sid=\d*$
5360 # Redirect Google search requests to MSN
5361 {+redirect{s@^http://[^/]*/search\?q=([^&]*).*@http://search.msn.com/results.aspx?q=$1@}}
5364 # Redirect MSN search requests to Yahoo
5365 {+redirect{s@^http://[^/]*/results\.aspx\?q=([^&]*).*@http://search.yahoo.com/search?p=$1@}}
5366 search.msn.com//results\.aspx\?q=
5368 # Redirect remote requests for this manual
5369 # to the local version delivered by Privoxy
5370 {+redirect{s@^http://www@http://config@}}
5371 www.privoxy.org/user-manual/</screen>
5380 <!-- ~~~~~ New section ~~~~~ -->
5381 <sect3 renderas="sect4" id="server-header-filter">
5382 <title>server-header-filter</title>
5386 <term>Typical use:</term>
5389 Rewrite or remove single server headers.
5395 <term>Effect:</term>
5398 All server headers to which this action applies are filtered on-the-fly
5399 through the specified regular expression based substitutions.
5406 <!-- boolean, parameterized, Multi-value -->
5408 <para>Parameterized.</para>
5413 <term>Parameter:</term>
5416 The name of a server-header filter, as defined in one of the
5417 <link linkend="filter-file">filter files</link>.
5426 Server-header filters are applied to each header on its own, not to
5427 all at once. This makes it easier to diagnose problems, but on the downside
5428 you can't write filters that only change header x if header y's value is z.
5429 You can do that by using tags though.
5432 Server-header filters are executed after the other header actions have finished
5433 and use their output as input.
5436 Please refer to the <link linkend="filter-file">filter file chapter</link>
5437 to learn which server-header filters are available by default, and how to
5444 <term>Example usage (section):</term>
5448 {+server-header-filter{html-to-xml}}
5449 example.org/xml-instance-that-is-delivered-as-html
5451 {+server-header-filter{xml-to-html}}
5452 example.org/instance-that-is-delivered-as-xml-but-is-not
5462 <!-- ~~~~~ New section ~~~~~ -->
5463 <sect3 renderas="sect4" id="server-header-tagger">
5464 <title>server-header-tagger</title>
5468 <term>Typical use:</term>
5471 Enable or disable filters based on the Content-Type header.
5477 <term>Effect:</term>
5480 Server headers to which this action applies are filtered on-the-fly through
5481 the specified regular expression based substitutions, the result is used as
5489 <!-- boolean, parameterized, Multi-value -->
5491 <para>Parameterized.</para>
5496 <term>Parameter:</term>
5499 The name of a server-header tagger, as defined in one of the
5500 <link linkend="filter-file">filter files</link>.
5509 Server-header taggers are applied to each header on its own,
5510 and as the header isn't modified, each tagger <quote>sees</quote>
5514 Server-header taggers are executed before all other header actions
5515 that modify server headers. Their tags can be used to control
5516 all of the other server-header actions, the content filters
5517 and the crunch actions (<link linkend="redirect">redirect</link>
5518 and <link linkend="block">block</link>).
5521 Obviously crunching based on tags created by server-header taggers
5522 doesn't prevent the request from showing up in the server's log file.
5529 <term>Example usage (section):</term>
5533 # Tag every request with the content type declared by the server
5534 {+server-header-tagger{content-type}}
5545 <!-- ~~~~~ New section ~~~~~ -->
5546 <sect3 renderas="sect4" id="session-cookies-only">
5547 <title>session-cookies-only</title>
5551 <term>Typical use:</term>
5554 Allow only temporary <quote>session</quote> cookies (for the current
5555 browser session <emphasis>only</emphasis>).
5561 <term>Effect:</term>
5564 Deletes the <quote>expires</quote> field from <quote>Set-Cookie:</quote>
5565 server headers. Most browsers will not store such cookies permanently and
5566 forget them in between sessions.
5573 <!-- Boolean, Parameterized, Multi-value -->
5575 <para>Boolean.</para>
5580 <term>Parameter:</term>
5592 This is less strict than <literal><link linkend="crunch-incoming-cookies">crunch-incoming-cookies</link></literal> /
5593 <literal><link linkend="crunch-outgoing-cookies">crunch-outgoing-cookies</link></literal> and allows you to browse
5594 websites that insist or rely on setting cookies, without compromising your privacy too badly.
5597 Most browsers will not permanently store cookies that have been processed by
5598 <literal>session-cookies-only</literal> and will forget about them between sessions.
5599 This makes profiling cookies useless, but won't break sites which require cookies so
5600 that you can log in for transactions. This is generally turned on for all
5601 sites, and is the recommended setting.
5604 It makes <emphasis>no sense at all</emphasis> to use <literal>session-cookies-only</literal>
5605 together with <literal><link linkend="crunch-incoming-cookies">crunch-incoming-cookies</link></literal> or
5606 <literal><link linkend="crunch-outgoing-cookies">crunch-outgoing-cookies</link></literal>. If you do, cookies
5607 will be plainly killed.
5610 Note that it is up to the browser how it handles such cookies without an <quote>expires</quote>
5611 field. If you use an exotic browser, you might want to try it out to be sure.
5614 This setting also has no effect on cookies that may have been stored
5615 previously by the browser before starting <application>Privoxy</application>.
5616 These would have to be removed manually.
5619 <application>Privoxy</application> also uses
5620 the <link linkend="filter-content-cookies">content-cookies filter</link>
5621 to block some types of cookies. Content cookies are not effected by
5622 <literal>session-cookies-only</literal>.
5628 <term>Example usage:</term>
5631 <screen>+session-cookies-only</screen>
5639 <!-- ~~~~~ New section ~~~~~ -->
5640 <sect3 renderas="sect4" id="set-image-blocker">
5641 <title>set-image-blocker</title>
5645 <term>Typical use:</term>
5647 <para>Choose the replacement for blocked images</para>
5652 <term>Effect:</term>
5655 This action alone doesn't do anything noticeable. If <emphasis>both</emphasis>
5656 <literal><link linkend="block">block</link></literal> <emphasis>and</emphasis> <literal><link
5657 linkend="handle-as-image">handle-as-image</link></literal> <emphasis>also</emphasis>
5658 apply, i.e. if the request is to be blocked as an image,
5659 <emphasis>then</emphasis> the parameter of this action decides what will be
5660 sent as a replacement.
5667 <!-- Boolean, Parameterized, Multi-value -->
5669 <para>Parameterized.</para>
5674 <term>Parameter:</term>
5679 <quote>pattern</quote> to send a built-in checkerboard pattern image. The image is visually
5680 decent, scales very well, and makes it obvious where banners were busted.
5685 <quote>blank</quote> to send a built-in transparent image. This makes banners disappear
5686 completely, but makes it hard to detect where <application>Privoxy</application> has blocked
5687 images on a given page and complicates troubleshooting if <application>Privoxy</application>
5688 has blocked innocent images, like navigation icons.
5693 <quote><replaceable class="parameter">target-url</replaceable></quote> to
5694 send a redirect to <replaceable class="parameter">target-url</replaceable>. You can redirect
5695 to any image anywhere, even in your local filesystem via <quote>file:///</quote> URL.
5696 (But note that not all browsers support redirecting to a local file system).
5699 A good application of redirects is to use special <application>Privoxy</application>-built-in
5700 URLs, which send the built-in images, as <replaceable class="parameter">target-url</replaceable>.
5701 This has the same visual effect as specifying <quote>blank</quote> or <quote>pattern</quote> in
5702 the first place, but enables your browser to cache the replacement image, instead of requesting
5703 it over and over again.
5714 The URLs for the built-in images are <quote>http://config.privoxy.org/send-banner?type=<replaceable
5715 class="parameter">type</replaceable></quote>, where <replaceable class="parameter">type</replaceable> is
5716 either <quote>blank</quote> or <quote>pattern</quote>.
5719 There is a third (advanced) type, called <quote>auto</quote>. It is <emphasis>NOT</emphasis> to be
5720 used in <literal>set-image-blocker</literal>, but meant for use from <link linkend="filter-file">filters</link>.
5721 Auto will select the type of image that would have applied to the referring page, had it been an image.
5727 <term>Example usage:</term>
5733 <screen>+set-image-blocker{pattern}</screen>
5736 Redirect to the BSD daemon:
5739 <screen>+set-image-blocker{http://www.freebsd.org/gifs/dae_up3.gif}</screen>
5742 Redirect to the built-in pattern for better caching:
5745 <screen>+set-image-blocker{http://config.privoxy.org/send-banner?type=pattern}</screen>
5753 <!-- ~~~~~ New section ~~~~~ -->
5755 <title>Summary</title>
5757 Note that many of these actions have the potential to cause a page to
5758 misbehave, possibly even not to display at all. There are many ways
5759 a site designer may choose to design his site, and what HTTP header
5760 content, and other criteria, he may depend on. There is no way to have hard
5761 and fast rules for all sites. See the <link
5762 linkend="ACTIONSANAT">Appendix</link> for a brief example on troubleshooting
5768 <!-- ~~~~~ New section ~~~~~ -->
5769 <sect2 id="aliases">
5770 <title>Aliases</title>
5772 Custom <quote>actions</quote>, known to <application>Privoxy</application>
5773 as <quote>aliases</quote>, can be defined by combining other actions.
5774 These can in turn be invoked just like the built-in actions.
5775 Currently, an alias name can contain any character except space, tab,
5777 <quote>{</quote> and <quote>}</quote>, but we <emphasis>strongly
5778 recommend</emphasis> that you only use <quote>a</quote> to <quote>z</quote>,
5779 <quote>0</quote> to <quote>9</quote>, <quote>+</quote>, and <quote>-</quote>.
5780 Alias names are not case sensitive, and are not required to start with a
5781 <quote>+</quote> or <quote>-</quote> sign, since they are merely textually
5785 Aliases can be used throughout the actions file, but they <emphasis>must be
5786 defined in a special section at the top of the file!</emphasis>
5787 And there can only be one such section per actions file. Each actions file may
5788 have its own alias section, and the aliases defined in it are only visible
5792 There are two main reasons to use aliases: One is to save typing for frequently
5793 used combinations of actions, the other one is a gain in flexibility: If you
5794 decide once how you want to handle shops by defining an alias called
5795 <quote>shop</quote>, you can later change your policy on shops in
5796 <emphasis>one</emphasis> place, and your changes will take effect everywhere
5797 in the actions file where the <quote>shop</quote> alias is used. Calling aliases
5798 by their purpose also makes your actions files more readable.
5801 Currently, there is one big drawback to using aliases, though:
5802 <application>Privoxy</application>'s built-in web-based action file
5803 editor honors aliases when reading the actions files, but it expands
5804 them before writing. So the effects of your aliases are of course preserved,
5805 but the aliases themselves are lost when you edit sections that use aliases
5810 Now let's define some aliases...
5815 # Useful custom aliases we can use later.
5817 # Note the (required!) section header line and that this section
5818 # must be at the top of the actions file!
5822 # These aliases just save typing later:
5823 # (Note that some already use other aliases!)
5825 +crunch-all-cookies = +<link linkend="CRUNCH-INCOMING-COOKIES">crunch-incoming-cookies</link> +<link linkend="CRUNCH-OUTGOING-COOKIES">crunch-outgoing-cookies</link>
5826 -crunch-all-cookies = -<link linkend="CRUNCH-INCOMING-COOKIES">crunch-incoming-cookies</link> -<link linkend="CRUNCH-OUTGOING-COOKIES">crunch-outgoing-cookies</link>
5827 +block-as-image = +block{Blocked image.} +handle-as-image
5828 allow-all-cookies = -crunch-all-cookies -<link linkend="SESSION-COOKIES-ONLY">session-cookies-only</link> -<link linkend="FILTER-CONTENT-COOKIES">filter{content-cookies}</link>
5830 # These aliases define combinations of actions
5831 # that are useful for certain types of sites:
5833 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>
5835 shop = -crunch-all-cookies -<link linkend="FILTER-ALL-POPUPS">filter{all-popups}</link>
5837 # Short names for other aliases, for really lazy people ;-)
5839 c0 = +crunch-all-cookies
5840 c1 = -crunch-all-cookies</screen>
5844 ...and put them to use. These sections would appear in the lower part of an
5845 actions file and define exceptions to the default actions (as specified further
5846 up for the <quote>/</quote> pattern):
5851 # These sites are either very complex or very keen on
5852 # user data and require minimal interference to work:
5855 .office.microsoft.com
5856 .windowsupdate.microsoft.com
5857 # Gmail is really mail.google.com, not gmail.com
5861 # Allow cookies (for setting and retrieving your customer data)
5865 .worldpay.com # for quietpc.com
5868 # These shops require pop-ups:
5870 {-filter{all-popups} -filter{unsolicited-popups}}
5872 .overclockers.co.uk</screen>
5876 Aliases like <quote>shop</quote> and <quote>fragile</quote> are typically used for
5877 <quote>problem</quote> sites that require more than one action to be disabled
5878 in order to function properly.
5884 <!-- ~~~~~ New section ~~~~~ -->
5885 <sect2 id="act-examples">
5886 <title>Actions Files Tutorial</title>
5888 The above chapters have shown <link linkend="actions-file">which actions files
5889 there are and how they are organized</link>, how actions are <link
5890 linkend="actions">specified</link> and <link linkend="actions-apply">applied
5891 to URLs</link>, how <link linkend="af-patterns">patterns</link> work, and how to
5892 define and use <link linkend="aliases">aliases</link>. Now, let's look at an
5893 example <filename>match-all.action</filename>, <filename>default.action</filename>
5894 and <filename>user.action</filename> file and see how all these pieces come together:
5898 <title>match-all.action</title>
5900 Remember <emphasis>all actions are disabled when matching starts</emphasis>,
5901 so we have to explicitly enable the ones we want.
5905 While the <filename>match-all.action</filename> file only contains a
5906 single section, it is probably the most important one. It has only one
5907 pattern, <quote><literal>/</literal></quote>, but this pattern
5908 <link linkend="af-patterns">matches all URLs</link>. Therefore, the set of
5909 actions used in this <quote>default</quote> section <emphasis>will
5910 be applied to all requests as a start</emphasis>. It can be partly or
5911 wholly overridden by other actions files like <filename>default.action</filename>
5912 and <filename>user.action</filename>, but it will still be largely responsible
5913 for your overall browsing experience.
5917 Again, at the start of matching, all actions are disabled, so there is
5918 no need to disable any actions here. (Remember: a <quote>+</quote>
5919 preceding the action name enables the action, a <quote>-</quote> disables!).
5920 Also note how this long line has been made more readable by splitting it into
5921 multiple lines with line continuation.
5927 +<link linkend="CHANGE-X-FORWARDED-FOR">change-x-forwarded-for{block}</link> \
5928 +<link linkend="HIDE-FROM-HEADER">hide-from-header{block}</link> \
5929 +<link linkend="SET-IMAGE-BLOCKER">set-image-blocker{pattern}</link> \
5936 The default behavior is now set.
5941 <title>default.action</title>
5944 If you aren't a developer, there's no need for you to edit the
5945 <filename>default.action</filename> file. It is maintained by
5946 the &my-app; developers and if you disagree with some of the
5947 sections, you should overrule them in your <filename>user.action</filename>.
5951 Understanding the <filename>default.action</filename> file can
5952 help you with your <filename>user.action</filename>, though.
5956 The first section in this file is a special section for internal use
5957 that prevents older &my-app; versions from reading the file:
5962 ##########################################################################
5963 # Settings -- Don't change! For internal Privoxy use ONLY.
5964 ##########################################################################
5966 for-privoxy-version=3.0.11</screen>
5970 After that comes the (optional) alias section. We'll use the example
5971 section from the above <link linkend="aliases">chapter on aliases</link>,
5972 that also explains why and how aliases are used:
5977 ##########################################################################
5979 ##########################################################################
5982 # These aliases just save typing later:
5983 # (Note that some already use other aliases!)
5985 +crunch-all-cookies = +<link linkend="CRUNCH-INCOMING-COOKIES">crunch-incoming-cookies</link> +<link linkend="CRUNCH-OUTGOING-COOKIES">crunch-outgoing-cookies</link>
5986 -crunch-all-cookies = -<link linkend="CRUNCH-INCOMING-COOKIES">crunch-incoming-cookies</link> -<link linkend="CRUNCH-OUTGOING-COOKIES">crunch-outgoing-cookies</link>
5987 +block-as-image = +block{Blocked image.} +handle-as-image
5988 mercy-for-cookies = -crunch-all-cookies -<link linkend="SESSION-COOKIES-ONLY">session-cookies-only</link> -<link linkend="FILTER-CONTENT-COOKIES">filter{content-cookies}</link>
5990 # These aliases define combinations of actions
5991 # that are useful for certain types of sites:
5993 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>
5994 shop = -crunch-all-cookies -<link linkend="FILTER-ALL-POPUPS">filter{all-popups}</link></screen>
5998 The first of our specialized sections is concerned with <quote>fragile</quote>
5999 sites, i.e. sites that require minimum interference, because they are either
6000 very complex or very keen on tracking you (and have mechanisms in place that
6001 make them unusable for people who avoid being tracked). We will simply use
6002 our pre-defined <literal>fragile</literal> alias instead of stating the list
6003 of actions explicitly:
6008 ##########################################################################
6009 # Exceptions for sites that'll break under the default action set:
6010 ##########################################################################
6012 # "Fragile" Use a minimum set of actions for these sites (see alias above):
6015 .office.microsoft.com # surprise, surprise!
6016 .windowsupdate.microsoft.com
6017 mail.google.com</screen>
6021 Shopping sites are not as fragile, but they typically
6022 require cookies to log in, and pop-up windows for shopping
6023 carts or item details. Again, we'll use a pre-defined alias:
6032 .worldpay.com # for quietpc.com
6034 .scan.co.uk</screen>
6038 The <literal><link linkend="FAST-REDIRECTS">fast-redirects</link></literal>
6039 action, which may have been enabled in <filename>match-all.action</filename>,
6040 breaks some sites. So disable it for popular sites where we know it misbehaves:
6045 { -<link linkend="FAST-REDIRECTS">fast-redirects</link> }
6049 .altavista.com/.*(like|url|link):http
6050 .altavista.com/trans.*urltext=http
6051 .nytimes.com</screen>
6055 It is important that <application>Privoxy</application> knows which
6056 URLs belong to images, so that <emphasis>if</emphasis> they are to
6057 be blocked, a substitute image can be sent, rather than an HTML page.
6058 Contacting the remote site to find out is not an option, since it
6059 would destroy the loading time advantage of banner blocking, and it
6060 would feed the advertisers information about you. We can mark any
6061 URL as an image with the <literal><link
6062 linkend="handle-as-image">handle-as-image</link></literal> action,
6063 and marking all URLs that end in a known image file extension is a
6069 ##########################################################################
6071 ##########################################################################
6073 # Define which file types will be treated as images, in case they get
6074 # blocked further down this file:
6076 { +<link linkend="HANDLE-AS-IMAGE">handle-as-image</link> }
6077 /.*\.(gif|jpe?g|png|bmp|ico)$</screen>
6081 And then there are known banner sources. They often use scripts to
6082 generate the banners, so it won't be visible from the URL that the
6083 request is for an image. Hence we block them <emphasis>and</emphasis>
6084 mark them as images in one go, with the help of our
6085 <literal>+block-as-image</literal> alias defined above. (We could of
6086 course just as well use <literal>+<link linkend="block">block</link>
6087 +<link linkend="handle-as-image">handle-as-image</link></literal> here.)
6088 Remember that the type of the replacement image is chosen by the
6089 <literal><link linkend="set-image-blocker">set-image-blocker</link></literal>
6090 action. Since all URLs have matched the default section with its
6091 <literal>+<link linkend="set-image-blocker">set-image-blocker</link>{pattern}</literal>
6092 action before, it still applies and needn't be repeated:
6097 # Known ad generators:
6102 .ad.*.doubleclick.net
6103 .a.yimg.com/(?:(?!/i/).)*$
6104 .a[0-9].yimg.com/(?:(?!/i/).)*$
6110 One of the most important jobs of <application>Privoxy</application>
6111 is to block banners. Many of these can be <quote>blocked</quote>
6112 by the <literal><link linkend="filter">filter</link>{banners-by-size}</literal>
6113 action, which we enabled above, and which deletes the references to banner
6114 images from the pages while they are loaded, so the browser doesn't request
6115 them anymore, and hence they don't need to be blocked here. But this naturally
6116 doesn't catch all banners, and some people choose not to use filters, so we
6117 need a comprehensive list of patterns for banner URLs here, and apply the
6118 <literal><link linkend="block">block</link></literal> action to them.
6121 First comes many generic patterns, which do most of the work, by
6122 matching typical domain and path name components of banners. Then comes
6123 a list of individual patterns for specific sites, which is omitted here
6124 to keep the example short:
6129 ##########################################################################
6130 # Block these fine banners:
6131 ##########################################################################
6132 { <link linkend="BLOCK">+block{Banner ads.}</link> }
6140 /.*count(er)?\.(pl|cgi|exe|dll|asp|php[34]?)
6141 /(?:.*/)?(publicite|werbung|rekla(ma|me|am)|annonse|maino(kset|nta|s)?)/
6143 # Site-specific patterns (abbreviated):
6145 .hitbox.com</screen>
6149 It's quite remarkable how many advertisers actually call their banner
6150 servers ads.<replaceable>company</replaceable>.com, or call the directory
6151 in which the banners are stored simply <quote>banners</quote>. So the above
6152 generic patterns are surprisingly effective.
6155 But being very generic, they necessarily also catch URLs that we don't want
6156 to block. The pattern <literal>.*ads.</literal> e.g. catches
6157 <quote>nasty-<emphasis>ads</emphasis>.nasty-corp.com</quote> as intended,
6158 but also <quote>downlo<emphasis>ads</emphasis>.sourcefroge.net</quote> or
6159 <quote><emphasis>ads</emphasis>l.some-provider.net.</quote> So here come some
6160 well-known exceptions to the <literal>+<link linkend="BLOCK">block</link></literal>
6164 Note that these are exceptions to exceptions from the default! Consider the URL
6165 <quote>downloads.sourcefroge.net</quote>: Initially, all actions are deactivated,
6166 so it wouldn't get blocked. Then comes the defaults section, which matches the
6167 URL, but just deactivates the <literal><link linkend="BLOCK">block</link></literal>
6168 action once again. Then it matches <literal>.*ads.</literal>, an exception to the
6169 general non-blocking policy, and suddenly
6170 <literal><link linkend="BLOCK">+block</link></literal> applies. And now, it'll match
6171 <literal>.*loads.</literal>, where <literal><link linkend="BLOCK">-block</link></literal>
6172 applies, so (unless it matches <emphasis>again</emphasis> further down) it ends up
6173 with no <literal><link linkend="BLOCK">block</link></literal> action applying.
6178 ##########################################################################
6179 # Save some innocent victims of the above generic block patterns:
6180 ##########################################################################
6184 { -<link linkend="BLOCK">block</link> }
6185 adv[io]*. # (for advogato.org and advice.*)
6186 adsl. # (has nothing to do with ads)
6187 adobe. # (has nothing to do with ads either)
6188 ad[ud]*. # (adult.* and add.*)
6189 .edu # (universities don't host banners (yet!))
6190 .*loads. # (downloads, uploads etc)
6198 www.globalintersec.com/adv # (adv = advanced)
6199 www.ugu.com/sui/ugu/adv</screen>
6203 Filtering source code can have nasty side effects,
6204 so make an exception for our friends at sourceforge.net,
6205 and all paths with <quote>cvs</quote> in them. Note that
6206 <literal>-<link linkend="FILTER">filter</link></literal>
6207 disables <emphasis>all</emphasis> filters in one fell swoop!
6212 # Don't filter code!
6214 { -<link linkend="FILTER">filter</link> }
6219 .sourceforge.net</screen>
6223 The actual <filename>default.action</filename> is of course much more
6224 comprehensive, but we hope this example made clear how it works.
6229 <sect3><title>user.action</title>
6232 So far we are painting with a broad brush by setting general policies,
6233 which would be a reasonable starting point for many people. Now,
6234 you might want to be more specific and have customized rules that
6235 are more suitable to your personal habits and preferences. These would
6236 be for narrowly defined situations like your ISP or your bank, and should
6237 be placed in <filename>user.action</filename>, which is parsed after all other
6238 actions files and hence has the last word, over-riding any previously
6239 defined actions. <filename>user.action</filename> is also a
6240 <emphasis>safe</emphasis> place for your personal settings, since
6241 <filename>default.action</filename> is actively maintained by the
6242 <application>Privoxy</application> developers and you'll probably want
6243 to install updated versions from time to time.
6247 So let's look at a few examples of things that one might typically do in
6248 <filename>user.action</filename>:
6252 <!-- brief sample user.action here -->
6256 # My user.action file. <fred@example.com></screen>
6260 As <link linkend="aliases">aliases</link> are local to the actions
6261 file that they are defined in, you can't use the ones from
6262 <filename>default.action</filename>, unless you repeat them here:
6267 # Aliases are local to the file they are defined in.
6268 # (Re-)define aliases for this file:
6272 # These aliases just save typing later, and the alias names should
6273 # be self explanatory.
6275 +crunch-all-cookies = +crunch-incoming-cookies +crunch-outgoing-cookies
6276 -crunch-all-cookies = -crunch-incoming-cookies -crunch-outgoing-cookies
6277 allow-all-cookies = -crunch-all-cookies -session-cookies-only
6278 allow-popups = -filter{all-popups}
6279 +block-as-image = +block{Blocked as image.} +handle-as-image
6280 -block-as-image = -block
6282 # These aliases define combinations of actions that are useful for
6283 # certain types of sites:
6285 fragile = -block -crunch-all-cookies -filter -fast-redirects -hide-referrer
6286 shop = -crunch-all-cookies allow-popups
6288 # Allow ads for selected useful free sites:
6290 allow-ads = -block -filter{banners-by-size} -filter{banners-by-link}
6292 # Alias for specific file types that are text, but might have conflicting
6293 # MIME types. We want the browser to force these to be text documents.
6294 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>
6299 Say you have accounts on some sites that you visit regularly, and
6300 you don't want to have to log in manually each time. So you'd like
6301 to allow persistent cookies for these sites. The
6302 <literal>allow-all-cookies</literal> alias defined above does exactly
6303 that, i.e. it disables crunching of cookies in any direction, and the
6304 processing of cookies to make them only temporary.
6309 { allow-all-cookies }
6313 .redhat.com</screen>
6317 Your bank is allergic to some filter, but you don't know which, so you disable them all:
6322 { -<link linkend="FILTER">filter</link> }
6323 .your-home-banking-site.com</screen>
6327 Some file types you may not want to filter for various reasons:
6332 # Technical documentation is likely to contain strings that might
6333 # erroneously get altered by the JavaScript-oriented filters:
6338 # And this stupid host sends streaming video with a wrong MIME type,
6339 # so that Privoxy thinks it is getting HTML and starts filtering:
6341 stupid-server.example.com/</screen>
6345 Example of a simple <link linkend="BLOCK">block</link> action. Say you've
6346 seen an ad on your favourite page on example.com that you want to get rid of.
6347 You have right-clicked the image, selected <quote>copy image location</quote>
6348 and pasted the URL below while removing the leading http://, into a
6349 <literal>{ +block{} }</literal> section. Note that <literal>{ +handle-as-image
6350 }</literal> need not be specified, since all URLs ending in
6351 <literal>.gif</literal> will be tagged as images by the general rules as set
6352 in default.action anyway:
6357 { +<link linkend="BLOCK">block</link>{Nasty ads.} }
6358 www.example.com/nasty-ads/sponsor\.gif
6359 another.example.net/more/junk/here/</screen>
6363 The URLs of dynamically generated banners, especially from large banner
6364 farms, often don't use the well-known image file name extensions, which
6365 makes it impossible for <application>Privoxy</application> to guess
6366 the file type just by looking at the URL.
6367 You can use the <literal>+block-as-image</literal> alias defined above for
6369 Note that objects which match this rule but then turn out NOT to be an
6370 image are typically rendered as a <quote>broken image</quote> icon by the
6371 browser. Use cautiously.
6380 ar.atwola.com/</screen>
6384 Now you noticed that the default configuration breaks Forbes Magazine,
6385 but you were too lazy to find out which action is the culprit, and you
6386 were again too lazy to give <link linkend="contact">feedback</link>, so
6387 you just used the <literal>fragile</literal> alias on the site, and
6388 -- <emphasis>whoa!</emphasis> -- it worked. The <literal>fragile</literal>
6389 aliases disables those actions that are most likely to break a site. Also,
6390 good for testing purposes to see if it is <application>Privoxy</application>
6391 that is causing the problem or not. We later find other regular sites
6392 that misbehave, and add those to our personalized list of troublemakers:
6400 .mybank.com</screen>
6404 You like the <quote>fun</quote> text replacements in <filename>default.filter</filename>,
6405 but it is disabled in the distributed actions file.
6406 So you'd like to turn it on in your private,
6407 update-safe config, once and for all:
6412 { +<link linkend="filter-fun">filter{fun}</link> }
6413 / # For ALL sites!</screen>
6417 Note that the above is not really a good idea: There are exceptions
6418 to the filters in <filename>default.action</filename> for things that
6419 really shouldn't be filtered, like code on CVS->Web interfaces. Since
6420 <filename>user.action</filename> has the last word, these exceptions
6421 won't be valid for the <quote>fun</quote> filtering specified here.
6425 You might also worry about how your favourite free websites are
6426 funded, and find that they rely on displaying banner advertisements
6427 to survive. So you might want to specifically allow banners for those
6428 sites that you feel provide value to you:
6440 Note that <literal>allow-ads</literal> has been aliased to
6441 <literal>-<link linkend="block">block</link></literal>,
6442 <literal>-<link linkend="filter-banners-by-size">filter{banners-by-size}</link></literal>, and
6443 <literal>-<link linkend="filter-banners-by-link">filter{banners-by-link}</link></literal> above.
6447 Invoke another alias here to force an over-ride of the MIME type <literal>
6448 application/x-sh</literal> which typically would open a download type
6449 dialog. In my case, I want to look at the shell script, and then I can save
6450 it should I choose to.
6460 <filename>user.action</filename> is generally the best place to define
6461 exceptions and additions to the default policies of
6462 <filename>default.action</filename>. Some actions are safe to have their
6463 default policies set here though. So let's set a default policy to have a
6464 <quote>blank</quote> image as opposed to the checkerboard pattern for
6465 <emphasis>ALL</emphasis> sites. <quote>/</quote> of course matches all URL
6471 { +<link linkend="set-image-blocker">set-image-blocker{blank}</link> }
6472 / # ALL sites</screen>
6478 <!-- ~ End section ~ -->
6482 <!-- ~ End section ~ -->
6484 <!-- ~~~~~~~~ New section Header ~~~~~~~~~ -->
6486 <sect1 id="filter-file">
6487 <title>Filter Files</title>
6490 On-the-fly text substitutions need
6491 to be defined in a <quote>filter file</quote>. Once defined, they
6492 can then be invoked as an <quote>action</quote>.
6496 &my-app; supports three different filter actions:
6497 <literal><link linkend="filter">filter</link></literal> to
6498 rewrite the content that is send to the client,
6499 <literal><link linkend="client-header-filter">client-header-filter</link></literal>
6500 to rewrite headers that are send by the client, and
6501 <literal><link linkend="server-header-filter">server-header-filter</link></literal>
6502 to rewrite headers that are send by the server.
6506 &my-app; also supports two tagger actions:
6507 <literal><link linkend="client-header-tagger">client-header-tagger</link></literal>
6509 <literal><link linkend="server-header-tagger">server-header-tagger</link></literal>.
6510 Taggers and filters use the same syntax in the filter files, the difference
6511 is that taggers don't modify the text they are filtering, but use a rewritten
6512 version of the filtered text as tag. The tags can then be used to change the
6513 applying actions through sections with <link linkend="tag-pattern">tag-patterns</link>.
6518 Multiple filter files can be defined through the <literal> <link
6519 linkend="filterfile">filterfile</link></literal> config directive. The filters
6520 as supplied by the developers are located in
6521 <filename>default.filter</filename>. It is recommended that any locally
6522 defined or modified filters go in a separately defined file such as
6523 <filename>user.filter</filename>.
6527 Common tasks for content filters are to eliminate common annoyances in
6528 HTML and JavaScript, such as pop-up windows,
6529 exit consoles, crippled windows without navigation tools, the
6530 infamous <BLINK> tag etc, to suppress images with certain
6531 width and height attributes (standard banner sizes or web-bugs),
6532 or just to have fun.
6536 Enabled content filters are applied to any content whose
6537 <quote>Content Type</quote> header is recognised as a sign
6538 of text-based content, with the exception of <literal>text/plain</literal>.
6539 Use the <link linkend="FORCE-TEXT-MODE">force-text-mode</link> action
6540 to also filter other content.
6544 Substitutions are made at the source level, so if you want to <quote>roll
6545 your own</quote> filters, you should first be familiar with HTML syntax,
6546 and, of course, regular expressions.
6550 Just like the <link linkend="actions-file">actions files</link>, the
6551 filter file is organized in sections, which are called <emphasis>filters</emphasis>
6552 here. Each filter consists of a heading line, that starts with one of the
6553 <emphasis>keywords</emphasis> <literal>FILTER:</literal>,
6554 <literal>CLIENT-HEADER-FILTER:</literal> or <literal>SERVER-HEADER-FILTER:</literal>
6555 followed by the filter's <emphasis>name</emphasis>, and a short (one line)
6556 <emphasis>description</emphasis> of what it does. Below that line
6557 come the <emphasis>jobs</emphasis>, i.e. lines that define the actual
6558 text substitutions. By convention, the name of a filter
6559 should describe what the filter <emphasis>eliminates</emphasis>. The
6560 comment is used in the <ulink url="http://config.privoxy.org/">web-based
6561 user interface</ulink>.
6565 Once a filter called <replaceable>name</replaceable> has been defined
6566 in the filter file, it can be invoked by using an action of the form
6567 +<literal><link linkend="filter">filter</link>{<replaceable>name</replaceable>}</literal>
6568 in any <link linkend="actions-file">actions file</link>.
6572 Filter definitions start with a header line that contains the filter
6573 type, the filter name and the filter description.
6574 A content filter header line for a filter called <quote>foo</quote> could look
6579 <screen>FILTER: foo Replace all "foo" with "bar"</screen>
6583 Below that line, and up to the next header line, come the jobs that
6584 define what text replacements the filter executes. They are specified
6585 in a syntax that imitates <ulink url="http://www.perl.org/">Perl</ulink>'s
6586 <literal>s///</literal> operator. If you are familiar with Perl, you
6587 will find this to be quite intuitive, and may want to look at the
6588 PCRS documentation for the subtle differences to Perl behaviour. Most
6589 notably, the non-standard option letter <literal>U</literal> is supported,
6590 which turns the default to ungreedy matching.
6595 <ulink url="http://en.wikipedia.org/wiki/Regular_expressions"><quote>Regular
6596 Expressions</quote></ulink>, you might want to take a look at
6597 the <link linkend="regex">Appendix on regular expressions</link>, and
6598 see the <ulink url="http://perldoc.perl.org/perlre.html">Perl
6600 <ulink url="http://perldoc.perl.org/perlop.html">the
6601 <literal>s///</literal> operator's syntax</ulink> and <ulink
6602 url="http://perldoc.perl.org/perlre.html">Perl-style regular
6603 expressions</ulink> in general.
6604 The below examples might also help to get you started.
6608 <!-- ~~~~~~~~ New section Header ~~~~~~~~~ -->
6610 <sect2><title>Filter File Tutorial</title>
6612 Now, let's complete our <quote>foo</quote> content filter. We have already defined
6613 the heading, but the jobs are still missing. Since all it does is to replace
6614 <quote>foo</quote> with <quote>bar</quote>, there is only one (trivial) job
6619 <screen>s/foo/bar/</screen>
6623 But wait! Didn't the comment say that <emphasis>all</emphasis> occurrences
6624 of <quote>foo</quote> should be replaced? Our current job will only take
6625 care of the first <quote>foo</quote> on each page. For global substitution,
6626 we'll need to add the <literal>g</literal> option:
6630 <screen>s/foo/bar/g</screen>
6634 Our complete filter now looks like this:
6637 <screen>FILTER: foo Replace all "foo" with "bar"
6638 s/foo/bar/g</screen>
6642 Let's look at some real filters for more interesting examples. Here you see
6643 a filter that protects against some common annoyances that arise from JavaScript
6644 abuse. Let's look at its jobs one after the other:
6650 FILTER: js-annoyances Get rid of particularly annoying JavaScript abuse
6652 # Get rid of JavaScript referrer tracking. Test page: http://www.randomoddness.com/untitled.htm
6654 s|(<script.*)document\.referrer(.*</script>)|$1"Not Your Business!"$2|Usg</screen>
6658 Following the header line and a comment, you see the job. Note that it uses
6659 <literal>|</literal> as the delimiter instead of <literal>/</literal>, because
6660 the pattern contains a forward slash, which would otherwise have to be escaped
6661 by a backslash (<literal>\</literal>).
6665 Now, let's examine the pattern: it starts with the text <literal><script.*</literal>
6666 enclosed in parentheses. Since the dot matches any character, and <literal>*</literal>
6667 means: <quote>Match an arbitrary number of the element left of myself</quote>, this
6668 matches <quote><script</quote>, followed by <emphasis>any</emphasis> text, i.e.
6669 it matches the whole page, from the start of the first <script> tag.
6673 That's more than we want, but the pattern continues: <literal>document\.referrer</literal>
6674 matches only the exact string <quote>document.referrer</quote>. The dot needed to
6675 be <emphasis>escaped</emphasis>, i.e. preceded by a backslash, to take away its
6676 special meaning as a joker, and make it just a regular dot. So far, the meaning is:
6677 Match from the start of the first <script> tag in a the page, up to, and including,
6678 the text <quote>document.referrer</quote>, if <emphasis>both</emphasis> are present
6679 in the page (and appear in that order).
6683 But there's still more pattern to go. The next element, again enclosed in parentheses,
6684 is <literal>.*</script></literal>. You already know what <literal>.*</literal>
6685 means, so the whole pattern translates to: Match from the start of the first <script>
6686 tag in a page to the end of the last <script> tag, provided that the text
6687 <quote>document.referrer</quote> appears somewhere in between.
6691 This is still not the whole story, since we have ignored the options and the parentheses:
6692 The portions of the page matched by sub-patterns that are enclosed in parentheses, will be
6693 remembered and be available through the variables <literal>$1, $2, ...</literal> in
6694 the substitute. The <literal>U</literal> option switches to ungreedy matching, which means
6695 that the first <literal>.*</literal> in the pattern will only <quote>eat up</quote> all
6696 text in between <quote><script</quote> and the <emphasis>first</emphasis> occurrence
6697 of <quote>document.referrer</quote>, and that the second <literal>.*</literal> will
6698 only span the text up to the <emphasis>first</emphasis> <quote></script></quote>
6699 tag. Furthermore, the <literal>s</literal> option says that the match may span
6700 multiple lines in the page, and the <literal>g</literal> option again means that the
6701 substitution is global.
6705 So, to summarize, the pattern means: Match all scripts that contain the text
6706 <quote>document.referrer</quote>. Remember the parts of the script from
6707 (and including) the start tag up to (and excluding) the string
6708 <quote>document.referrer</quote> as <literal>$1</literal>, and the part following
6709 that string, up to and including the closing tag, as <literal>$2</literal>.
6713 Now the pattern is deciphered, but wasn't this about substituting things? So
6714 lets look at the substitute: <literal>$1"Not Your Business!"$2</literal> is
6715 easy to read: The text remembered as <literal>$1</literal>, followed by
6716 <literal>"Not Your Business!"</literal> (<emphasis>including</emphasis>
6717 the quotation marks!), followed by the text remembered as <literal>$2</literal>.
6718 This produces an exact copy of the original string, with the middle part
6719 (the <quote>document.referrer</quote>) replaced by <literal>"Not Your
6720 Business!"</literal>.
6724 The whole job now reads: Replace <quote>document.referrer</quote> by
6725 <literal>"Not Your Business!"</literal> wherever it appears inside a
6726 <script> tag. Note that this job won't break JavaScript syntax,
6727 since both the original and the replacement are syntactically valid
6728 string objects. The script just won't have access to the referrer
6729 information anymore.
6733 We'll show you two other jobs from the JavaScript taming department, but
6734 this time only point out the constructs of special interest:
6739 # The status bar is for displaying link targets, not pointless blahblah
6741 s/window\.status\s*=\s*(['"]).*?\1/dUmMy=1/ig</screen>
6745 <literal>\s</literal> stands for whitespace characters (space, tab, newline,
6746 carriage return, form feed), so that <literal>\s*</literal> means: <quote>zero
6747 or more whitespace</quote>. The <literal>?</literal> in <literal>.*?</literal>
6748 makes this matching of arbitrary text ungreedy. (Note that the <literal>U</literal>
6749 option is not set). The <literal>['"]</literal> construct means: <quote>a single
6750 <emphasis>or</emphasis> a double quote</quote>. Finally, <literal>\1</literal> is
6751 a back-reference to the first parenthesis just like <literal>$1</literal> above,
6752 with the difference that in the <emphasis>pattern</emphasis>, a backslash indicates
6753 a back-reference, whereas in the <emphasis>substitute</emphasis>, it's the dollar.
6757 So what does this job do? It replaces assignments of single- or double-quoted
6758 strings to the <quote>window.status</quote> object with a dummy assignment
6759 (using a variable name that is hopefully odd enough not to conflict with
6760 real variables in scripts). Thus, it catches many cases where e.g. pointless
6761 descriptions are displayed in the status bar instead of the link target when
6762 you move your mouse over links.
6767 # Kill OnUnload popups. Yummy. Test: http://www.zdnet.com/zdsubs/yahoo/tree/yfs.html
6769 s/(<body [^>]*)onunload(.*>)/$1never$2/iU</screen>
6774 <ulink url="http://www.w3.org/TR/2000/REC-DOM-Level-2-Events-20001113/events.html#Events-eventgroupings-htmlevents">OnUnload
6775 event binding</ulink> in the HTML DOM was a <emphasis>CRIME</emphasis>.
6776 When I close a browser window, I want it to close and die. Basta.
6777 This job replaces the <quote>onunload</quote> attribute in
6778 <quote><body></quote> tags with the dummy word <literal>never</literal>.
6779 Note that the <literal>i</literal> option makes the pattern matching
6780 case-insensitive. Also note that ungreedy matching alone doesn't always guarantee
6781 a minimal match: In the first parenthesis, we had to use <literal>[^>]*</literal>
6782 instead of <literal>.*</literal> to prevent the match from exceeding the
6783 <body> tag if it doesn't contain <quote>OnUnload</quote>, but the page's
6788 The last example is from the fun department:
6793 FILTER: fun Fun text replacements
6795 # Spice the daily news:
6797 s/microsoft(?!\.com)/MicroSuck/ig</screen>
6801 Note the <literal>(?!\.com)</literal> part (a so-called negative lookahead)
6802 in the job's pattern, which means: Don't match, if the string
6803 <quote>.com</quote> appears directly following <quote>microsoft</quote>
6804 in the page. This prevents links to microsoft.com from being trashed, while
6805 still replacing the word everywhere else.
6810 # Buzzword Bingo (example for extended regex syntax)
6812 s* industry[ -]leading \
6814 | customer[ -]focused \
6815 | market[ -]driven \
6816 | award[ -]winning # Comments are OK, too! \
6817 | high[ -]performance \
6818 | solutions[ -]based \
6822 *<font color="red"><b>BINGO!</b></font> \
6827 The <literal>x</literal> option in this job turns on extended syntax, and allows for
6828 e.g. the liberal use of (non-interpreted!) whitespace for nicer formatting.
6836 <!-- ~~~~~~~~ New section Header ~~~~~~~~~ -->
6838 <sect2 id="predefined-filters"><title>The Pre-defined Filters</title>
6842 Note each filter is also listed in the +filter action section above. Please
6843 keep these listings in sync.
6848 The distribution <filename>default.filter</filename> file contains a selection of
6849 pre-defined filters for your convenience:
6854 <term><emphasis>js-annoyances</emphasis></term>
6857 The purpose of this filter is to get rid of particularly annoying JavaScript abuse.
6862 replaces JavaScript references to the browser's referrer information
6863 with the string "Not Your Business!". This compliments the <literal><link
6864 linkend="hide-referrer">hide-referrer</link></literal> action on the content level.
6869 removes the bindings to the DOM's
6870 <ulink url="http://www.w3.org/TR/2000/REC-DOM-Level-2-Events-20001113/events.html#Events-eventgroupings-htmlevents">unload
6871 event</ulink> which we feel has no right to exist and is responsible for most <quote>exit consoles</quote>, i.e.
6872 nasty windows that pop up when you close another one.
6877 removes code that causes new windows to be opened with undesired properties, such as being
6878 full-screen, non-resizeable, without location, status or menu bar etc.
6884 Use with caution. This is an aggressive filter, and can break sites that
6885 rely heavily on JavaScript.
6891 <term><emphasis>js-events</emphasis></term>
6894 This is a very radical measure. It removes virtually all JavaScript event bindings, which
6895 means that scripts can not react to user actions such as mouse movements or clicks, window
6896 resizing etc, anymore. Use with caution!
6899 We <emphasis>strongly discourage</emphasis> using this filter as a default since it breaks
6900 many legitimate scripts. It is meant for use only on extra-nasty sites (should you really
6907 <term><emphasis>html-annoyances</emphasis></term>
6910 This filter will undo many common instances of HTML based abuse.
6913 The <literal>BLINK</literal> and <literal>MARQUEE</literal> tags
6914 are neutralized (yeah baby!), and browser windows will be created as
6915 resizeable (as of course they should be!), and will have location,
6916 scroll and menu bars -- even if specified otherwise.
6922 <term><emphasis>content-cookies</emphasis></term>
6925 Most cookies are set in the HTTP dialog, where they can be intercepted
6927 <literal><link linkend="crunch-incoming-cookies">crunch-incoming-cookies</link></literal>
6928 and <literal><link linkend="crunch-outgoing-cookies">crunch-outgoing-cookies</link></literal>
6929 actions. But web sites increasingly make use of HTML meta tags and JavaScript
6930 to sneak cookies to the browser on the content level.
6933 This filter disables most HTML and JavaScript code that reads or sets
6934 cookies. It cannot detect all clever uses of these types of code, so it
6935 should not be relied on as an absolute fix. Use it wherever you would also
6936 use the cookie crunch actions.
6942 <term><emphasis>refresh-tags</emphasis></term>
6945 Disable any refresh tags if the interval is greater than nine seconds (so
6946 that redirections done via refresh tags are not destroyed). This is useful
6947 for dial-on-demand setups, or for those who find this HTML feature
6954 <term><emphasis>unsolicited-popups</emphasis></term>
6957 This filter attempts to prevent only <quote>unsolicited</quote> pop-up
6958 windows from opening, yet still allow pop-up windows that the user
6959 has explicitly chosen to open. It was added in version 3.0.1,
6960 as an improvement over earlier such filters.
6963 Technical note: The filter works by redefining the window.open JavaScript
6964 function to a dummy function, <literal>PrivoxyWindowOpen()</literal>,
6965 during the loading and rendering phase of each HTML page access, and
6966 restoring the function afterward.
6969 This is recommended only for browsers that cannot perform this function
6970 reliably themselves. And be aware that some sites require such windows
6971 in order to function normally. Use with caution.
6977 <term><emphasis>all-popups</emphasis></term>
6980 Attempt to prevent <emphasis>all</emphasis> pop-up windows from opening.
6981 Note this should be used with even more discretion than the above, since
6982 it is more likely to break some sites that require pop-ups for normal
6983 usage. Use with caution.
6989 <term><emphasis>img-reorder</emphasis></term>
6992 This is a helper filter that has no value if used alone. It makes the
6993 <literal>banners-by-size</literal> and <literal>banners-by-link</literal>
6994 (see below) filters more effective and should be enabled together with them.
7000 <term><emphasis>banners-by-size</emphasis></term>
7003 This filter removes image tags purely based on what size they are. Fortunately
7004 for us, many ads and banner images tend to conform to certain standardized
7005 sizes, which makes this filter quite effective for ad stripping purposes.
7008 Occasionally this filter will cause false positives on images that are not ads,
7009 but just happen to be of one of the standard banner sizes.
7012 Recommended only for those who require extreme ad blocking. The default
7013 block rules should catch 95+% of all ads <emphasis>without</emphasis> this filter enabled.
7019 <term><emphasis>banners-by-link</emphasis></term>
7022 This is an experimental filter that attempts to kill any banners if
7023 their URLs seem to point to known or suspected click trackers. It is currently
7024 not of much value and is not recommended for use by default.
7030 <term><emphasis>webbugs</emphasis></term>
7033 Webbugs are small, invisible images (technically 1X1 GIF images), that
7034 are used to track users across websites, and collect information on them.
7035 As an HTML page is loaded by the browser, an embedded image tag causes the
7036 browser to contact a third-party site, disclosing the tracking information
7037 through the requested URL and/or cookies for that third-party domain, without
7038 the user ever becoming aware of the interaction with the third-party site.
7039 HTML-ized spam also uses a similar technique to verify email addresses.
7042 This filter removes the HTML code that loads such <quote>webbugs</quote>.
7048 <term><emphasis>tiny-textforms</emphasis></term>
7051 A rather special-purpose filter that can be used to enlarge textareas (those
7052 multi-line text boxes in web forms) and turn off hard word wrap in them.
7053 It was written for the sourceforge.net tracker system where such boxes are
7054 a nuisance, but it can be handy on other sites, too.
7057 It is not recommended to use this filter as a default.
7063 <term><emphasis>jumping-windows</emphasis></term>
7066 Many consider windows that move, or resize themselves to be abusive. This filter
7067 neutralizes the related JavaScript code. Note that some sites might not display
7068 or behave as intended when using this filter. Use with caution.
7074 <term><emphasis>frameset-borders</emphasis></term>
7077 Some web designers seem to assume that everyone in the world will view their
7078 web sites using the same browser brand and version, screen resolution etc,
7079 because only that assumption could explain why they'd use static frame sizes,
7080 yet prevent their frames from being resized by the user, should they be too
7081 small to show their whole content.
7084 This filter removes the related HTML code. It should only be applied to sites
7091 <term><emphasis>demoronizer</emphasis></term>
7094 Many Microsoft products that generate HTML use non-standard extensions (read:
7095 violations) of the ISO 8859-1 aka Latin-1 character set. This can cause those
7096 HTML documents to display with errors on standard-compliant platforms.
7099 This filter translates the MS-only characters into Latin-1 equivalents.
7100 It is not necessary when using MS products, and will cause corruption of
7101 all documents that use 8-bit character sets other than Latin-1. It's mostly
7102 worthwhile for Europeans on non-MS platforms, if weird garbage characters
7103 sometimes appear on some pages, or user agents that don't correct for this on
7106 My version of Mozilla (ancient) shows litte square boxes for quote
7107 characters, and apostrophes on moronized pages. So many pages have this, I
7108 can read them fine now. HB 08/27/06
7115 <term><emphasis>shockwave-flash</emphasis></term>
7118 A filter for shockwave haters. As the name suggests, this filter strips code
7119 out of web pages that is used to embed shockwave flash objects.
7127 <term><emphasis>quicktime-kioskmode</emphasis></term>
7130 Change HTML code that embeds Quicktime objects so that kioskmode, which
7131 prevents saving, is disabled.
7137 <term><emphasis>fun</emphasis></term>
7140 Text replacements for subversive browsing fun. Make fun of your favorite
7141 Monopolist or play buzzword bingo.
7147 <term><emphasis>crude-parental</emphasis></term>
7150 A demonstration-only filter that shows how <application>Privoxy</application>
7151 can be used to delete web content on a keyword basis.
7157 <term><emphasis>ie-exploits</emphasis></term>
7160 An experimental collection of text replacements to disable malicious HTML and JavaScript
7161 code that exploits known security holes in Internet Explorer.
7164 Presently, it only protects against Nimda and a cross-site scripting bug, and
7165 would need active maintenance to provide more substantial protection.
7171 <term><emphasis>site-specifics</emphasis></term>
7174 Some web sites have very specific problems, the cure for which doesn't apply
7175 anywhere else, or could even cause damage on other sites.
7178 This is a collection of such site-specific cures which should only be applied
7179 to the sites they were intended for, which is what the supplied
7180 <filename>default.action</filename> file does. Users shouldn't need to change
7181 anything regarding this filter.
7187 <term><emphasis>google</emphasis></term>
7190 A CSS based block for Google text ads. Also removes a width limitation
7191 and the toolbar advertisement.
7197 <term><emphasis>yahoo</emphasis></term>
7200 Another CSS based block, this time for Yahoo text ads. And removes
7201 a width limitation as well.
7207 <term><emphasis>msn</emphasis></term>
7210 Another CSS based block, this time for MSN text ads. And removes
7211 tracking URLs, as well as a width limitation.
7217 <term><emphasis>blogspot</emphasis></term>
7220 Cleans up some Blogspot blogs. Read the fine print before using this one!
7223 This filter also intentionally removes some navigation stuff and sets the
7224 page width to 100%. As a result, some rounded <quote>corners</quote> would
7225 appear to early or not at all and as fixing this would require a browser
7226 that understands background-size (CSS3), they are removed instead.
7232 <term><emphasis>xml-to-html</emphasis></term>
7235 Server-header filter to change the Content-Type from xml to html.
7241 <term><emphasis>html-to-xml</emphasis></term>
7244 Server-header filter to change the Content-Type from html to xml.
7250 <term><emphasis>no-ping</emphasis></term>
7253 Removes the non-standard <literal>ping</literal> attribute from
7254 anchor and area HTML tags.
7260 <term><emphasis>hide-tor-exit-notation</emphasis></term>
7263 Client-header filter to remove the <command>Tor</command> exit node notation
7264 found in Host and Referer headers.
7267 If &my-app; and <command>Tor</command> are chained and &my-app;
7268 is configured to use socks4a, one can use <quote>http://www.example.org.foobar.exit/</quote>
7269 to access the host <quote>www.example.org</quote> through the
7270 <command>Tor</command> exit node <quote>foobar</quote>.
7273 As the HTTP client isn't aware of this notation, it treats the
7274 whole string <quote>www.example.org.foobar.exit</quote> as host and uses it
7275 for the <quote>Host</quote> and <quote>Referer</quote> headers. From the
7276 server's point of view the resulting headers are invalid and can cause problems.
7279 An invalid <quote>Referer</quote> header can trigger <quote>hot-linking</quote>
7280 protections, an invalid <quote>Host</quote> header will make it impossible for
7281 the server to find the right vhost (several domains hosted on the same IP address).
7284 This client-header filter removes the <quote>foo.exit</quote> part in those headers
7285 to prevent the mentioned problems. Note that it only modifies
7286 the HTTP headers, it doesn't make it impossible for the server
7287 to detect your <command>Tor</command> exit node based on the IP address
7288 the request is coming from.
7295 <term><emphasis> </emphasis></term>
7309 <!-- ~ End section ~ -->
7313 <!-- ~~~~~ New section ~~~~~ -->
7315 <sect1 id="templates">
7316 <title>Privoxy's Template Files</title>
7318 All <application>Privoxy</application> built-in pages, i.e. error pages such as the
7319 <ulink url="http://show-the-404-error.page"><quote>404 - No Such Domain</quote>
7320 error page</ulink>, the <ulink
7321 url="http://ads.bannerserver.example.com/nasty-ads/sponsor.html"><quote>BLOCKED</quote>
7323 and all pages of its <ulink url="http://config.privoxy.org/">web-based
7324 user interface</ulink>, are generated from <emphasis>templates</emphasis>.
7325 (<application>Privoxy</application> must be running for the above links to work as
7330 These templates are stored in a subdirectory of the <link linkend="confdir">configuration
7331 directory</link> called <filename>templates</filename>. On Unixish platforms,
7333 <ulink url="file:///etc/privoxy/templates/"><filename>/etc/privoxy/templates/</filename></ulink>.
7337 The templates are basically normal HTML files, but with place-holders (called symbols
7338 or exports), which <application>Privoxy</application> fills at run time. It
7339 is possible to edit the templates with a normal text editor, should you want
7340 to customize them. (<emphasis>Not recommended for the casual
7341 user</emphasis>). Should you create your own custom templates, you should use
7342 the <filename>config</filename> setting <link linkend="templdir">templdir</link>
7343 to specify an alternate location, so your templates do not get overwritten
7347 Note that just like in configuration files, lines starting
7348 with <literal>#</literal> are ignored when the templates are filled in.
7352 The place-holders are of the form <literal>@name@</literal>, and you will
7353 find a list of available symbols, which vary from template to template,
7354 in the comments at the start of each file. Note that these comments are not
7355 always accurate, and that it's probably best to look at the existing HTML
7356 code to find out which symbols are supported and what they are filled in with.
7360 A special application of this substitution mechanism is to make whole
7361 blocks of HTML code disappear when a specific symbol is set. We use this
7362 for many purposes, one of them being to include the beta warning in all
7363 our user interface (CGI) pages when <application>Privoxy</application>
7364 is in an alpha or beta development stage:
7369 <!-- @if-unstable-start -->
7371 ... beta warning HTML code goes here ...
7373 <!-- if-unstable-end@ --></screen>
7377 If the "unstable" symbol is set, everything in between and including
7378 <literal>@if-unstable-start</literal> and <literal>if-unstable-end@</literal>
7379 will disappear, leaving nothing but an empty comment:
7383 <screen><!-- --></screen>
7387 There's also an if-then-else construct and an <literal>#include</literal>
7388 mechanism, but you'll sure find out if you are inclined to edit the
7393 All templates refer to a style located at
7394 <ulink url="http://config.privoxy.org/send-stylesheet"><literal>http://config.privoxy.org/send-stylesheet</literal></ulink>.
7395 This is, of course, locally served by <application>Privoxy</application>
7396 and the source for it can be found and edited in the
7397 <filename>cgi-style.css</filename> template.
7402 <!-- ~ End section ~ -->
7406 <!-- ~~~~~ New section ~~~~~ -->
7408 <sect1 id="contact"><title>Contacting the Developers, Bug Reporting and Feature
7411 <!-- Include contacting.sgml boilerplate: -->
7413 <!-- end boilerplate -->
7417 <!-- ~ End section ~ -->
7420 <!-- ~~~~~ New section ~~~~~ -->
7421 <sect1 id="copyright"><title>Privoxy Copyright, License and History</title>
7423 <!-- Include copyright.sgml: -->
7425 <!-- end copyright -->
7427 <!-- ~~~~~ New section ~~~~~ -->
7428 <sect2><title>License</title>
7429 <!-- Include copyright.sgml: -->
7431 <!-- end copyright -->
7433 <!-- ~ End section ~ -->
7436 <!-- ~~~~~ New section ~~~~~ -->
7438 <sect2 id="history"><title>History</title>
7439 <!-- Include history.sgml: -->
7441 <!-- end history -->
7444 <sect2 id="authors"><title>Authors</title>
7445 <!-- Include p-authors.sgml: -->
7447 <!-- end authors -->
7452 <!-- ~ End section ~ -->
7455 <!-- ~~~~~ New section ~~~~~ -->
7456 <sect1 id="seealso"><title>See Also</title>
7457 <!-- Include seealso.sgml: -->
7459 <!-- end seealso -->
7464 <!-- ~~~~~ New section ~~~~~ -->
7465 <sect1 id="appendix"><title>Appendix</title>
7468 <!-- ~~~~~ New section ~~~~~ -->
7470 <title>Regular Expressions</title>
7472 <application>Privoxy</application> uses Perl-style <quote>regular
7473 expressions</quote> in its <link linkend="actions-file">actions
7474 files</link> and <link linkend="filter-file">filter file</link>,
7475 through the <ulink url="http://www.pcre.org/">PCRE</ulink> and
7478 <ulink url="http://www.oesterhelt.org/pcrs/">PCRS</ulink> libraries.
7480 <application>PCRS</application> libraries.
7484 If you are reading this, you probably don't understand what <quote>regular
7485 expressions</quote> are, or what they can do. So this will be a very brief
7486 introduction only. A full explanation would require a <ulink
7487 url="http://www.oreilly.com/catalog/regex/">book</ulink> ;-)
7491 Regular expressions provide a language to describe patterns that can be
7492 run against strings of characters (letter, numbers, etc), to see if they
7493 match the string or not. The patterns are themselves (sometimes complex)
7494 strings of literal characters, combined with wild-cards, and other special
7495 characters, called meta-characters. The <quote>meta-characters</quote> have
7496 special meanings and are used to build complex patterns to be matched against.
7497 Perl Compatible Regular Expressions are an especially convenient
7498 <quote>dialect</quote> of the regular expression language.
7502 To make a simple analogy, we do something similar when we use wild-card
7503 characters when listing files with the <command>dir</command> command in DOS.
7504 <literal>*.*</literal> matches all filenames. The <quote>special</quote>
7505 character here is the asterisk which matches any and all characters. We can be
7506 more specific and use <literal>?</literal> to match just individual
7507 characters. So <quote>dir file?.text</quote> would match
7508 <quote>file1.txt</quote>, <quote>file2.txt</quote>, etc. We are pattern
7509 matching, using a similar technique to <quote>regular expressions</quote>!
7513 Regular expressions do essentially the same thing, but are much, much more
7514 powerful. There are many more <quote>special characters</quote> and ways of
7515 building complex patterns however. Let's look at a few of the common ones,
7516 and then some examples:
7521 <emphasis>.</emphasis> - Matches any single character, e.g. <quote>a</quote>,
7522 <quote>A</quote>, <quote>4</quote>, <quote>:</quote>, or <quote>@</quote>.
7524 </simplelist></para>
7528 <emphasis>?</emphasis> - The preceding character or expression is matched ZERO or ONE
7531 </simplelist></para>
7535 <emphasis>+</emphasis> - The preceding character or expression is matched ONE or MORE
7538 </simplelist></para>
7542 <emphasis>*</emphasis> - The preceding character or expression is matched ZERO or MORE
7545 </simplelist></para>
7549 <emphasis>\</emphasis> - The <quote>escape</quote> character denotes that
7550 the following character should be taken literally. This is used where one of the
7551 special characters (e.g. <quote>.</quote>) needs to be taken literally and
7552 not as a special meta-character. Example: <quote>example\.com</quote>, makes
7553 sure the period is recognized only as a period (and not expanded to its
7554 meta-character meaning of any single character).
7556 </simplelist></para>
7560 <emphasis>[ ]</emphasis> - Characters enclosed in brackets will be matched if
7561 any of the enclosed characters are encountered. For instance, <quote>[0-9]</quote>
7562 matches any numeric digit (zero through nine). As an example, we can combine
7563 this with <quote>+</quote> to match any digit one of more times: <quote>[0-9]+</quote>.
7565 </simplelist></para>
7569 <emphasis>( )</emphasis> - parentheses are used to group a sub-expression,
7570 or multiple sub-expressions.
7572 </simplelist></para>
7576 <emphasis>|</emphasis> - The <quote>bar</quote> character works like an
7577 <quote>or</quote> conditional statement. A match is successful if the
7578 sub-expression on either side of <quote>|</quote> matches. As an example:
7579 <quote>/(this|that) example/</quote> uses grouping and the bar character
7580 and would match either <quote>this example</quote> or <quote>that
7581 example</quote>, and nothing else.
7583 </simplelist></para>
7586 These are just some of the ones you are likely to use when matching URLs with
7587 <application>Privoxy</application>, and is a long way from a definitive
7588 list. This is enough to get us started with a few simple examples which may
7589 be more illuminating:
7593 <emphasis><literal>/.*/banners/.*</literal></emphasis> - A simple example
7594 that uses the common combination of <quote>.</quote> and <quote>*</quote> to
7595 denote any character, zero or more times. In other words, any string at all.
7596 So we start with a literal forward slash, then our regular expression pattern
7597 (<quote>.*</quote>) another literal forward slash, the string
7598 <quote>banners</quote>, another forward slash, and lastly another
7599 <quote>.*</quote>. We are building
7600 a directory path here. This will match any file with the path that has a
7601 directory named <quote>banners</quote> in it. The <quote>.*</quote> matches
7602 any characters, and this could conceivably be more forward slashes, so it
7603 might expand into a much longer looking path. For example, this could match:
7604 <quote>/eye/hate/spammers/banners/annoy_me_please.gif</quote>, or just
7605 <quote>/banners/annoying.html</quote>, or almost an infinite number of other
7606 possible combinations, just so it has <quote>banners</quote> in the path
7611 And now something a little more complex:
7615 <emphasis><literal>/.*/adv((er)?ts?|ertis(ing|ements?))?/</literal></emphasis> -
7616 We have several literal forward slashes again (<quote>/</quote>), so we are
7617 building another expression that is a file path statement. We have another
7618 <quote>.*</quote>, so we are matching against any conceivable sub-path, just so
7619 it matches our expression. The only true literal that <emphasis>must
7620 match</emphasis> our pattern is <application>adv</application>, together with
7621 the forward slashes. What comes after the <quote>adv</quote> string is the
7626 Remember the <quote>?</quote> means the preceding expression (either a
7627 literal character or anything grouped with <quote>(...)</quote> in this case)
7628 can exist or not, since this means either zero or one match. So
7629 <quote>((er)?ts?|ertis(ing|ements?))</quote> is optional, as are the
7630 individual sub-expressions: <quote>(er)</quote>,
7631 <quote>(ing|ements?)</quote>, and the <quote>s</quote>. The <quote>|</quote>
7632 means <quote>or</quote>. We have two of those. For instance,
7633 <quote>(ing|ements?)</quote>, can expand to match either <quote>ing</quote>
7634 <emphasis>OR</emphasis> <quote>ements?</quote>. What is being done here, is an
7635 attempt at matching as many variations of <quote>advertisement</quote>, and
7636 similar, as possible. So this would expand to match just <quote>adv</quote>,
7637 or <quote>advert</quote>, or <quote>adverts</quote>, or
7638 <quote>advertising</quote>, or <quote>advertisement</quote>, or
7639 <quote>advertisements</quote>. You get the idea. But it would not match
7640 <quote>advertizements</quote> (with a <quote>z</quote>). We could fix that by
7641 changing our regular expression to:
7642 <quote>/.*/adv((er)?ts?|erti(s|z)(ing|ements?))?/</quote>, which would then match
7647 <emphasis><literal>/.*/advert[0-9]+\.(gif|jpe?g)</literal></emphasis> - Again
7648 another path statement with forward slashes. Anything in the square brackets
7649 <quote>[ ]</quote> can be matched. This is using <quote>0-9</quote> as a
7650 shorthand expression to mean any digit one through nine. It is the same as
7651 saying <quote>0123456789</quote>. So any digit matches. The <quote>+</quote>
7652 means one or more of the preceding expression must be included. The preceding
7653 expression here is what is in the square brackets -- in this case, any digit
7654 one through nine. Then, at the end, we have a grouping: <quote>(gif|jpe?g)</quote>.
7655 This includes a <quote>|</quote>, so this needs to match the expression on
7656 either side of that bar character also. A simple <quote>gif</quote> on one side, and the other
7657 side will in turn match either <quote>jpeg</quote> or <quote>jpg</quote>,
7658 since the <quote>?</quote> means the letter <quote>e</quote> is optional and
7659 can be matched once or not at all. So we are building an expression here to
7660 match image GIF or JPEG type image file. It must include the literal
7661 string <quote>advert</quote>, then one or more digits, and a <quote>.</quote>
7662 (which is now a literal, and not a special character, since it is escaped
7663 with <quote>\</quote>), and lastly either <quote>gif</quote>, or
7664 <quote>jpeg</quote>, or <quote>jpg</quote>. Some possible matches would
7665 include: <quote>//advert1.jpg</quote>,
7666 <quote>/nasty/ads/advert1234.gif</quote>,
7667 <quote>/banners/from/hell/advert99.jpg</quote>. It would not match
7668 <quote>advert1.gif</quote> (no leading slash), or
7669 <quote>/adverts232.jpg</quote> (the expression does not include an
7670 <quote>s</quote>), or <quote>/advert1.jsp</quote> (<quote>jsp</quote> is not
7671 in the expression anywhere).
7675 We are barely scratching the surface of regular expressions here so that you
7676 can understand the default <application>Privoxy</application>
7677 configuration files, and maybe use this knowledge to customize your own
7678 installation. There is much, much more that can be done with regular
7679 expressions. Now that you know enough to get started, you can learn more on
7684 More reading on Perl Compatible Regular expressions:
7685 <ulink url="http://perldoc.perl.org/perlre.html">http://perldoc.perl.org/perlre.html</ulink>
7689 For information on regular expression based substitutions and their applications
7690 in filters, please see the <link linkend="filter-file">filter file tutorial</link>
7695 <!-- ~ End section ~ -->
7698 <!-- ~~~~~ New section ~~~~~ -->
7700 <title>Privoxy's Internal Pages</title>
7703 Since <application>Privoxy</application> proxies each requested
7704 web page, it is easy for <application>Privoxy</application> to
7705 trap certain special URLs. In this way, we can talk directly to
7706 <application>Privoxy</application>, and see how it is
7707 configured, see how our rules are being applied, change these
7708 rules and other configuration options, and even turn
7709 <application>Privoxy's</application> filtering off, all with
7715 The URLs listed below are the special ones that allow direct access
7716 to <application>Privoxy</application>. Of course,
7717 <application>Privoxy</application> must be running to access these. If
7718 not, you will get a friendly error message. Internet access is not
7731 <ulink url="http://config.privoxy.org/">http://config.privoxy.org/</ulink>
7735 There is a shortcut: <ulink url="http://p.p/">http://p.p/</ulink> (But it
7736 doesn't provide a fall-back to a real page, in case the request is not
7737 sent through <application>Privoxy</application>)
7743 Show information about the current configuration, including viewing and
7744 editing of actions files:
7748 <ulink url="http://config.privoxy.org/show-status">http://config.privoxy.org/show-status</ulink>
7755 Show the source code version numbers:
7759 <ulink url="http://config.privoxy.org/show-version">http://config.privoxy.org/show-version</ulink>
7766 Show the browser's request headers:
7770 <ulink url="http://config.privoxy.org/show-request">http://config.privoxy.org/show-request</ulink>
7777 Show which actions apply to a URL and why:
7781 <ulink url="http://config.privoxy.org/show-url-info">http://config.privoxy.org/show-url-info</ulink>
7788 Toggle Privoxy on or off. This feature can be turned off/on in the main
7789 <filename>config</filename> file. When toggled <quote>off</quote>, <quote>Privoxy</quote>
7790 continues to run, but only as a pass-through proxy, with no actions taking
7795 <ulink url="http://config.privoxy.org/toggle">http://config.privoxy.org/toggle</ulink>
7799 Short cuts. Turn off, then on:
7803 <ulink url="http://config.privoxy.org/toggle?set=disable">http://config.privoxy.org/toggle?set=disable</ulink>
7808 <ulink url="http://config.privoxy.org/toggle?set=enable">http://config.privoxy.org/toggle?set=enable</ulink>
7817 These may be bookmarked for quick reference. See next.
7821 <sect3 id="bookmarklets">
7822 <title>Bookmarklets</title>
7824 Below are some <quote>bookmarklets</quote> to allow you to easily access a
7825 <quote>mini</quote> version of some of <application>Privoxy's</application>
7826 special pages. They are designed for MS Internet Explorer, but should work
7827 equally well in Netscape, Mozilla, and other browsers which support
7828 JavaScript. They are designed to run directly from your bookmarks - not by
7829 clicking the links below (although that should work for testing).
7832 To save them, right-click the link and choose <quote>Add to Favorites</quote>
7833 (IE) or <quote>Add Bookmark</quote> (Netscape). You will get a warning that
7834 the bookmark <quote>may not be safe</quote> - just click OK. Then you can run the
7835 Bookmarklet directly from your favorites/bookmarks. For even faster access,
7836 you can put them on the <quote>Links</quote> bar (IE) or the <quote>Personal
7837 Toolbar</quote> (Netscape), and run them with a single click.
7846 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>
7853 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>
7860 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)
7867 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>
7873 <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>
7879 <ulink url="javascript:void(window.open('http://config.privoxy.org/show-url-info?url='+escape(location.href),'Why').focus());">Privoxy - Why?</ulink>
7886 Credit: The site which gave us the general idea for these bookmarklets is
7887 <ulink url="http://www.bookmarklets.com/">www.bookmarklets.com</ulink>. They
7888 have more information about bookmarklets.
7897 <!-- ~~~~~ New section ~~~~~ -->
7899 <title>Chain of Events</title>
7901 Let's take a quick look at how some of <application>Privoxy's</application>
7902 core features are triggered, and the ensuing sequence of events when a web
7903 page is requested by your browser:
7910 First, your web browser requests a web page. The browser knows to send
7911 the request to <application>Privoxy</application>, which will in turn,
7912 relay the request to the remote web server after passing the following
7918 <application>Privoxy</application> traps any request for its own internal CGI
7919 pages (e.g <ulink url="http://p.p/">http://p.p/</ulink>) and sends the CGI page back to the browser.
7924 Next, <application>Privoxy</application> checks to see if the URL
7926 linkend="BLOCK"><quote>+block</quote></link> patterns. If
7927 so, the URL is then blocked, and the remote web server will not be contacted.
7928 <link linkend="HANDLE-AS-IMAGE"><quote>+handle-as-image</quote></link>
7930 <link linkend="HANDLE-AS-EMPTY-DOCUMENT"><quote>+handle-as-empty-document</quote></link>
7931 are then checked, and if there is no match, an
7932 HTML <quote>BLOCKED</quote> page is sent back to the browser. Otherwise, if
7933 it does match, an image is returned for the former, and an empty text
7934 document for the latter. The type of image would depend on the setting of
7935 <link linkend="SET-IMAGE-BLOCKER"><quote>+set-image-blocker</quote></link>
7936 (blank, checkerboard pattern, or an HTTP redirect to an image elsewhere).
7941 Untrusted URLs are blocked. If URLs are being added to the
7942 <filename>trust</filename> file, then that is done.
7947 If the URL pattern matches the <link
7948 linkend="FAST-REDIRECTS"><quote>+fast-redirects</quote></link> action,
7949 it is then processed. Unwanted parts of the requested URL are stripped.
7954 Now the rest of the client browser's request headers are processed. If any
7955 of these match any of the relevant actions (e.g. <link
7956 linkend="HIDE-USER-AGENT"><quote>+hide-user-agent</quote></link>,
7957 etc.), headers are suppressed or forged as determined by these actions and
7963 Now the web server starts sending its response back (i.e. typically a web
7969 First, the server headers are read and processed to determine, among other
7970 things, the MIME type (document type) and encoding. The headers are then
7971 filtered as determined by the
7972 <link linkend="CRUNCH-INCOMING-COOKIES"><quote>+crunch-incoming-cookies</quote></link>,
7973 <link linkend="SESSION-COOKIES-ONLY"><quote>+session-cookies-only</quote></link>,
7974 and <link linkend="DOWNGRADE-HTTP-VERSION"><quote>+downgrade-http-version</quote></link>
7980 If any <link linkend="FILTER"><quote>+filter</quote></link> action
7982 linkend="DEANIMATE-GIFS"><quote>+deanimate-gifs</quote></link>
7983 action applies (and the document type fits the action), the rest of the page is
7984 read into memory (up to a configurable limit). Then the filter rules (from
7985 <filename>default.filter</filename> and any other filter files) are
7986 processed against the buffered content. Filters are applied in the order
7987 they are specified in one of the filter files. Animated GIFs, if present,
7988 are reduced to either the first or last frame, depending on the action
7989 setting.The entire page, which is now filtered, is then sent by
7990 <application>Privoxy</application> back to your browser.
7993 If neither a <link linkend="FILTER"><quote>+filter</quote></link> action
7995 linkend="DEANIMATE-GIFS"><quote>+deanimate-gifs</quote></link>
7996 matches, then <application>Privoxy</application> passes the raw data through
7997 to the client browser as it becomes available.
8002 As the browser receives the now (possibly filtered) page content, it
8003 reads and then requests any URLs that may be embedded within the page
8004 source, e.g. ad images, stylesheets, JavaScript, other HTML documents (e.g.
8005 frames), sounds, etc. For each of these objects, the browser issues a
8006 separate request (this is easily viewable in <application>Privoxy's</application>
8007 logs). And each such request is in turn processed just as above. Note that a
8008 complex web page will have many, many such embedded URLs. If these
8009 secondary requests are to a different server, then quite possibly a very
8010 differing set of actions is triggered.
8017 NOTE: This is somewhat of a simplistic overview of what happens with each URL
8018 request. For the sake of brevity and simplicity, we have focused on
8019 <application>Privoxy's</application> core features only.
8025 <!-- ~~~~~ New section ~~~~~ -->
8026 <sect2 id="actionsanat">
8027 <title>Troubleshooting: Anatomy of an Action</title>
8030 The way <application>Privoxy</application> applies
8031 <link linkend="ACTIONS">actions</link> and <link linkend="FILTER">filters</link>
8032 to any given URL can be complex, and not always so
8033 easy to understand what is happening. And sometimes we need to be able to
8034 <emphasis>see</emphasis> just what <application>Privoxy</application> is
8035 doing. Especially, if something <application>Privoxy</application> is doing
8036 is causing us a problem inadvertently. It can be a little daunting to look at
8037 the actions and filters files themselves, since they tend to be filled with
8038 <link linkend="regex">regular expressions</link> whose consequences are not
8043 One quick test to see if <application>Privoxy</application> is causing a problem
8044 or not, is to disable it temporarily. This should be the first troubleshooting
8045 step. See <link linkend="bookmarklets">the Bookmarklets</link> section on a quick
8046 and easy way to do this (be sure to flush caches afterward!). Looking at the
8047 logs is a good idea too. (Note that both the toggle feature and logging are
8048 enabled via <filename>config</filename> file settings, and may need to be
8049 turned <quote>on</quote>.)
8052 Another easy troubleshooting step to try is if you have done any
8053 customization of your installation, revert back to the installed
8054 defaults and see if that helps. There are times the developers get complaints
8055 about one thing or another, and the problem is more related to a customized
8056 configuration issue.
8060 <application>Privoxy</application> also provides the
8061 <ulink url="http://config.privoxy.org/show-url-info">http://config.privoxy.org/show-url-info</ulink>
8062 page that can show us very specifically how <application>actions</application>
8063 are being applied to any given URL. This is a big help for troubleshooting.
8067 First, enter one URL (or partial URL) at the prompt, and then
8068 <application>Privoxy</application> will tell us
8069 how the current configuration will handle it. This will not
8070 help with filtering effects (i.e. the <link
8071 linkend="FILTER"><quote>+filter</quote></link> action) from
8072 one of the filter files since this is handled very
8073 differently and not so easy to trap! It also will not tell you about any other
8074 URLs that may be embedded within the URL you are testing. For instance, images
8075 such as ads are expressed as URLs within the raw page source of HTML pages. So
8076 you will only get info for the actual URL that is pasted into the prompt area
8077 -- not any sub-URLs. If you want to know about embedded URLs like ads, you
8078 will have to dig those out of the HTML source. Use your browser's <quote>View
8079 Page Source</quote> option for this. Or right click on the ad, and grab the
8084 Let's try an example, <ulink url="http://google.com">google.com</ulink>,
8085 and look at it one section at a time in a sample configuration (your real
8086 configuration may vary):
8091 Matches for http://www.google.com:
8093 In file: default.action <guibutton>[ View ]</guibutton> <guibutton>[ Edit ]</guibutton>
8095 {+change-x-forwarded-for{block}
8096 +deanimate-gifs {last}
8097 +fast-redirects {check-decoded-url}
8098 +filter {refresh-tags}
8099 +filter {img-reorder}
8100 +filter {banners-by-size}
8102 +filter {jumping-windows}
8103 +filter {ie-exploits}
8104 +hide-from-header {block}
8105 +hide-referrer {forge}
8106 +session-cookies-only
8107 +set-image-blocker {pattern}
8110 { -session-cookies-only }
8116 In file: user.action <guibutton>[ View ]</guibutton> <guibutton>[ Edit ]</guibutton>
8117 (no matches in this file)
8122 This is telling us how we have defined our
8123 <link linkend="ACTIONS"><quote>actions</quote></link>, and
8124 which ones match for our test case, <quote>google.com</quote>.
8125 Displayed is all the actions that are available to us. Remember,
8126 the <literal>+</literal> sign denotes <quote>on</quote>. <literal>-</literal>
8127 denotes <quote>off</quote>. So some are <quote>on</quote> here, but many
8128 are <quote>off</quote>. Each example we try may provide a slightly different
8129 end result, depending on our configuration directives.
8133 is for our <filename>default.action</filename> file. The large, multi-line
8134 listing, is how the actions are set to match for all URLs, i.e. our default
8135 settings. If you look at your <quote>actions</quote> file, this would be the
8136 section just below the <quote>aliases</quote> section near the top. This
8137 will apply to all URLs as signified by the single forward slash at the end
8138 of the listing -- <quote> / </quote>.
8142 But we have defined additional actions that would be exceptions to these general
8143 rules, and then we list specific URLs (or patterns) that these exceptions
8144 would apply to. Last match wins. Just below this then are two explicit
8145 matches for <quote>.google.com</quote>. The first is negating our previous
8146 cookie setting, which was for <link
8147 linkend="SESSION-COOKIES-ONLY"><quote>+session-cookies-only</quote></link>
8148 (i.e. not persistent). So we will allow persistent cookies for google, at
8149 least that is how it is in this example. The second turns
8150 <emphasis>off</emphasis> any <link
8151 linkend="FAST-REDIRECTS"><quote>+fast-redirects</quote></link>
8152 action, allowing this to take place unmolested. Note that there is a leading
8153 dot here -- <quote>.google.com</quote>. This will match any hosts and
8154 sub-domains, in the google.com domain also, such as
8155 <quote>www.google.com</quote> or <quote>mail.google.com</quote>. But it would not
8156 match <quote>www.google.de</quote>! So, apparently, we have these two actions
8157 defined as exceptions to the general rules at the top somewhere in the lower
8158 part of our <filename>default.action</filename> file, and
8159 <quote>google.com</quote> is referenced somewhere in these latter sections.
8163 Then, for our <filename>user.action</filename> file, we again have no hits.
8164 So there is nothing google-specific that we might have added to our own, local
8165 configuration. If there was, those actions would over-rule any actions from
8166 previously processed files, such as <filename>default.action</filename>.
8167 <filename>user.action</filename> typically has the last word. This is the
8168 best place to put hard and fast exceptions,
8172 And finally we pull it all together in the bottom section and summarize how
8173 <application>Privoxy</application> is applying all its <quote>actions</quote>
8174 to <quote>google.com</quote>:
8185 +change-x-forwarded-for{block}
8186 -client-header-filter{hide-tor-exit-notation}
8187 -content-type-overwrite
8188 -crunch-client-header
8189 -crunch-if-none-match
8190 -crunch-incoming-cookies
8191 -crunch-outgoing-cookies
8192 -crunch-server-header
8193 +deanimate-gifs {last}
8194 -downgrade-http-version
8197 -filter {content-cookies}
8198 -filter {all-popups}
8199 -filter {banners-by-link}
8200 -filter {tiny-textforms}
8201 -filter {frameset-borders}
8202 -filter {demoronizer}
8203 -filter {shockwave-flash}
8204 -filter {quicktime-kioskmode}
8206 -filter {crude-parental}
8207 -filter {site-specifics}
8208 -filter {js-annoyances}
8209 -filter {html-annoyances}
8210 +filter {refresh-tags}
8211 -filter {unsolicited-popups}
8212 +filter {img-reorder}
8213 +filter {banners-by-size}
8215 +filter {jumping-windows}
8216 +filter {ie-exploits}
8223 -handle-as-empty-document
8225 -hide-accept-language
8226 -hide-content-disposition
8227 +hide-from-header {block}
8228 -hide-if-modified-since
8229 +hide-referrer {forge}
8232 -overwrite-last-modified
8233 -prevent-compression
8235 -server-header-filter{xml-to-html}
8236 -server-header-filter{html-to-xml}
8237 -session-cookies-only
8238 +set-image-blocker {pattern} </screen>
8242 Notice the only difference here to the previous listing, is to
8243 <quote>fast-redirects</quote> and <quote>session-cookies-only</quote>,
8244 which are activated specifically for this site in our configuration,
8245 and thus show in the <quote>Final Results</quote>.
8249 Now another example, <quote>ad.doubleclick.net</quote>:
8255 { +block{Domains starts with "ad"} }
8258 { +block{Domain contains "ad"} }
8261 { +block{Doubleclick banner server} +handle-as-image }
8262 .[a-vx-z]*.doubleclick.net
8267 We'll just show the interesting part here - the explicit matches. It is
8268 matched three different times. Two <quote>+block{}</quote> sections,
8269 and a <quote>+block{} +handle-as-image</quote>,
8270 which is the expanded form of one of our aliases that had been defined as:
8271 <quote>+block-as-image</quote>. (<link
8272 linkend="ALIASES"><quote>Aliases</quote></link> are defined in
8273 the first section of the actions file and typically used to combine more
8278 Any one of these would have done the trick and blocked this as an unwanted
8279 image. This is unnecessarily redundant since the last case effectively
8280 would also cover the first. No point in taking chances with these guys
8281 though ;-) Note that if you want an ad or obnoxious
8282 URL to be invisible, it should be defined as <quote>ad.doubleclick.net</quote>
8283 is done here -- as both a <link
8284 linkend="BLOCK"><quote>+block{}</quote></link>
8285 <emphasis>and</emphasis> an
8286 <link linkend="HANDLE-AS-IMAGE"><quote>+handle-as-image</quote></link>.
8287 The custom alias <quote><literal>+block-as-image</literal></quote> just
8288 simplifies the process and make it more readable.
8292 One last example. Let's try <quote>http://www.example.net/adsl/HOWTO/</quote>.
8293 This one is giving us problems. We are getting a blank page. Hmmm ...
8299 Matches for http://www.example.net/adsl/HOWTO/:
8301 In file: default.action <guibutton>[ View ]</guibutton> <guibutton>[ Edit ]</guibutton>
8305 +change-x-forwarded-for{block}
8306 -client-header-filter{hide-tor-exit-notation}
8307 -content-type-overwrite
8308 -crunch-client-header
8309 -crunch-if-none-match
8310 -crunch-incoming-cookies
8311 -crunch-outgoing-cookies
8312 -crunch-server-header
8314 -downgrade-http-version
8315 +fast-redirects {check-decoded-url}
8317 -filter {content-cookies}
8318 -filter {all-popups}
8319 -filter {banners-by-link}
8320 -filter {tiny-textforms}
8321 -filter {frameset-borders}
8322 -filter {demoronizer}
8323 -filter {shockwave-flash}
8324 -filter {quicktime-kioskmode}
8326 -filter {crude-parental}
8327 -filter {site-specifics}
8328 -filter {js-annoyances}
8329 -filter {html-annoyances}
8330 +filter {refresh-tags}
8331 -filter {unsolicited-popups}
8332 +filter {img-reorder}
8333 +filter {banners-by-size}
8335 +filter {jumping-windows}
8336 +filter {ie-exploits}
8343 -handle-as-empty-document
8345 -hide-accept-language
8346 -hide-content-disposition
8347 +hide-from-header{block}
8348 +hide-referer{forge}
8350 -overwrite-last-modified
8351 +prevent-compression
8353 -server-header-filter{xml-to-html}
8354 -server-header-filter{html-to-xml}
8355 +session-cookies-only
8356 +set-image-blocker{blank} }
8359 { +block{Path contains "ads".} +handle-as-image }
8365 Ooops, the <quote>/adsl/</quote> is matching <quote>/ads</quote> in our
8366 configuration! But we did not want this at all! Now we see why we get the
8367 blank page. It is actually triggering two different actions here, and
8368 the effects are aggregated so that the URL is blocked, and &my-app; is told
8369 to treat the block as if it were an image. But this is, of course, all wrong.
8370 We could now add a new action below this (or better in our own
8371 <filename>user.action</filename> file) that explicitly
8372 <emphasis>un</emphasis> blocks (
8373 <link linkend="BLOCK"><quote>{-block}</quote></link>) paths with
8374 <quote>adsl</quote> in them (remember, last match in the configuration
8375 wins). There are various ways to handle such exceptions. Example:
8387 Now the page displays ;-)
8388 Remember to flush your browser's caches when making these kinds of changes to
8389 your configuration to insure that you get a freshly delivered page! Or, try
8390 using <literal>Shift+Reload</literal>.
8394 But now what about a situation where we get no explicit matches like
8401 { +block{Path starts with "ads".} +handle-as-image }
8407 That actually was very helpful and pointed us quickly to where the problem
8408 was. If you don't get this kind of match, then it means one of the default
8409 rules in the first section of <filename>default.action</filename> is causing
8410 the problem. This would require some guesswork, and maybe a little trial and
8411 error to isolate the offending rule. One likely cause would be one of the
8412 <link linkend="FILTER"><quote>+filter</quote></link> actions.
8413 These tend to be harder to troubleshoot.
8414 Try adding the URL for the site to one of aliases that turn off
8415 <link linkend="FILTER"><quote>+filter</quote></link>:
8423 .worldpay.com # for quietpc.com
8431 <quote><literal>{ shop }</literal></quote> is an <quote>alias</quote> that expands to
8432 <quote><literal>{ -filter -session-cookies-only }</literal></quote>.
8433 Or you could do your own exception to negate filtering:
8441 # Disable ALL filter actions for sites in this section
8449 This would turn off all filtering for these sites. This is best
8450 put in <filename>user.action</filename>, for local site
8451 exceptions. Note that when a simple domain pattern is used by itself (without
8452 the subsequent path portion), all sub-pages within that domain are included
8453 automatically in the scope of the action.
8457 Images that are inexplicably being blocked, may well be hitting the
8458 <link linkend="FILTER-BANNERS-BY-SIZE"><quote>+filter{banners-by-size}</quote></link>
8460 that images of certain sizes are ad banners (works well
8461 <emphasis>most of the time</emphasis> since these tend to be standardized).
8465 <quote><literal>{ fragile }</literal></quote> is an alias that disables most
8466 actions that are the most likely to cause trouble. This can be used as a
8467 last resort for problem sites.
8473 # Handle with care: easy to break
8475 mybank.example.com</screen>
8480 <emphasis>Remember to flush caches!</emphasis> Note that the
8481 <literal>mail.google</literal> reference lacks the TLD portion (e.g.
8482 <quote>.com</quote>). This will effectively match any TLD with
8483 <literal>google</literal> in it, such as <literal>mail.google.de.</literal>,
8487 If this still does not work, you will have to go through the remaining
8488 actions one by one to find which one(s) is causing the problem.
8497 This program is free software; you can redistribute it
8498 and/or modify it under the terms of the GNU General
8499 Public License as published by the Free Software
8500 Foundation; either version 2 of the License, or (at
8501 your option) any later version.
8503 This program is distributed in the hope that it will
8504 be useful, but WITHOUT ANY WARRANTY; without even the
8505 implied warranty of MERCHANTABILITY or FITNESS FOR A
8506 PARTICULAR PURPOSE. See the GNU General Public
8507 License for more details.
8509 The GNU General Public License should be included with
8510 this file. If not, you can view it at
8511 http://www.gnu.org/copyleft/gpl.html
8512 or write to the Free Software Foundation, Inc.,
8513 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301,
projects / privoxy.git / blob