1 <!DOCTYPE article PUBLIC "-//OASIS//DTD DocBook V3.1//EN" [
2 <!entity % dummy "IGNORE">
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4 <!entity newfeatures SYSTEM "newfeatures.sgml">
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6 <!entity seealso SYSTEM "seealso.sgml">
7 <!entity buildsource SYSTEM "buildsource.sgml">
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10 <!entity copyright SYSTEM "copyright.sgml">
11 <!entity license SYSTEM "license.sgml">
12 <!entity GPLv2 SYSTEM "../../LICENSE">
13 <!entity p-authors SYSTEM "p-authors.sgml">
14 <!entity config SYSTEM "p-config.sgml">
15 <!entity changelog SYSTEM "changelog.sgml">
16 <!entity p-version "3.0.21">
17 <!entity p-status "stable">
18 <!entity % p-authors-formal "INCLUDE"> <!-- include additional text, etc -->
19 <!entity % p-not-stable "IGNORE">
20 <!entity % p-stable "INCLUDE">
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24 <!entity % user-man "IGNORE">
25 <!entity % config-file "IGNORE">
26 <!entity % p-supp-userman "IGNORE"> <!-- Omit some from supported.sgml -->
27 <!entity my-copy "©"> <!-- kludge for docbook2man -->
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30 <!entity my-app "<application>Privoxy</application>">
33 File : $Source: /cvsroot/ijbswa/current/doc/source/user-manual.sgml,v $
36 This file belongs into
37 ijbswa.sourceforge.net:/home/groups/i/ij/ijbswa/htdocs/
39 $Id: user-manual.sgml,v 2.175 2013/03/20 11:30:28 fabiankeil Exp $
41 Copyright (C) 2001-2013 Privoxy Developers http://www.privoxy.org/
44 ========================================================================
45 NOTE: Please read developer-manual/documentation.html before touching
46 anything in this, or other Privoxy documentation.
47 ========================================================================
54 <title>Privoxy &p-version; User Manual</title>
58 <!-- Completely the wrong markup, but very little is allowed -->
59 <!-- in this part of an article. FIXME -->
60 <link linkend="copyright">Copyright</link> &my-copy; 2001-2013 by
61 <ulink url="http://www.privoxy.org/">Privoxy Developers</ulink>
65 <pubdate>$Id: user-manual.sgml,v 2.175 2013/03/20 11:30:28 fabiankeil Exp $</pubdate>
69 Note: the following should generate a separate page, and a live link to it,
70 all nicely done. But it doesn't for some mysterious reason. Please leave
71 commented unless it can be fixed proper. For the time being, the
72 copyright/license declarations will be in their own sgml.
85 This is here to keep vim syntax file from breaking :/
86 If I knew enough to fix it, I would.
87 PLEASE DO NOT REMOVE! HB: hal@foobox.net
93 The <citetitle>Privoxy User Manual</citetitle> gives users information on how to
94 install, configure and use <ulink
95 url="http://www.privoxy.org/">Privoxy</ulink>.
98 <!-- Include privoxy.sgml boilerplate: -->
100 <!-- end privoxy.sgml -->
103 You can find the latest version of the <citetitle>Privoxy User Manual</citetitle> at <ulink
104 url="http://www.privoxy.org/user-manual/">http://www.privoxy.org/user-manual/</ulink>.
105 Please see the <link linkend="contact">Contact section</link> on how to
106 contact the developers.
110 <!-- Feel free to send a note to the developers at <email>ijbswa-developers@lists.sourceforge.net</email>. -->
116 <!-- ~~~~~ New section ~~~~~ -->
117 <sect1 label="1" id="introduction"><title>Introduction</title>
119 This documentation is included with the current &p-status; version of
120 <application>Privoxy</application>, &p-version;<![%p-not-stable;[,
121 and is mostly complete at this point. The most up to date reference for the
122 time being is still the comments in the source files and in the individual
123 configuration files. Development of a new version is currently nearing
124 completion, and includes significant changes and enhancements over
128 <!-- include only in non-stable versions -->
131 Since this is a &p-status; version, not all new features are well tested. This
132 documentation may be slightly out of sync as a result (especially with
133 CVS sources). And there <emphasis>may be</emphasis> bugs, though hopefully
138 <!-- ~~~~~ New section ~~~~~ -->
139 <sect2 id="features"><title>Features</title>
141 In addition to the core
142 features of ad blocking and
143 <ulink url="http://en.wikipedia.org/wiki/Browser_cookie">cookie</ulink> management,
144 <application>Privoxy</application> provides many supplemental
145 features<![%p-not-stable;[, some of them currently under development]]>,
146 that give the end-user more control, more privacy and more freedom:
148 <!-- Include newfeatures.sgml boilerplate here: -->
150 <!-- end boilerplate -->
155 <!-- ~ End section ~ -->
158 <!-- ~~~~~ New section ~~~~~ -->
159 <sect1 id="installation"><title>Installation</title>
162 <application>Privoxy</application> is available both in convenient pre-compiled
163 packages for a wide range of operating systems, and as raw source code.
164 For most users, we recommend using the packages, which can be downloaded from our
165 <ulink url="http://sourceforge.net/projects/ijbswa/">Privoxy Project
171 On some platforms, the installer may remove previously installed versions, if
172 found. (See below for your platform). In any case <emphasis>be sure to backup
173 your old configuration if it is valuable to you.</emphasis> See the <link
174 linkend="upgradersnote">note to upgraders</link> section below.
177 <!-- ~~~~~ New section ~~~~~ -->
178 <sect2 id="installation-packages"><title>Binary Packages</title>
180 How to install the binary packages depends on your operating system:
183 <!-- XXX: The installation sections should be sorted -->
185 <!-- ~~~~~ New section ~~~~~ -->
186 <sect3 id="installation-deb"><title>Debian and Ubuntu</title>
188 DEBs can be installed with <literal>apt-get install privoxy</literal>,
189 and will use <filename>/etc/privoxy</filename> for the location of
194 <!-- ~~~~~ New section ~~~~~ -->
195 <sect3 id="installation-pack-win"><title>Windows</title>
198 Just double-click the installer, which will guide you through
199 the installation process. You will find the configuration files
200 in the same directory as you installed <application>Privoxy</application> in.
203 Version 3.0.5 beta introduced full <application>Windows</application> service
204 functionality. On Windows only, the <application>Privoxy</application>
205 program has two new command line arguments to install and uninstall
206 <application>Privoxy</application> as a <emphasis>service</emphasis>.
210 <term>Arguments:</term>
213 <replaceable class="parameter">--install</replaceable>[:<replaceable class="parameter">service_name</replaceable>]
216 <replaceable class="parameter">--uninstall</replaceable>[:<replaceable class="parameter">service_name</replaceable>]
222 After invoking <application>Privoxy</application> with
223 <command>--install</command>, you will need to bring up the
224 <application>Windows</application> service console to assign the user you
225 want <application>Privoxy</application> to run under, and whether or not you
226 want it to run whenever the system starts. You can start the
227 <application>Windows</application> services console with the following
228 command: <command>services.msc</command>. If you do not take the manual step
229 of modifying <application>Privoxy's</application> service settings, it will
230 not start. Note too that you will need to give Privoxy a user account that
231 actually exists, or it will not be permitted to
232 write to its log and configuration files.
237 <!-- ~~~~~ New section ~~~~~ -->
238 <sect3 id="installation-os2"><title>OS/2</title>
241 First, make sure that no previous installations of
242 <application>Junkbuster</application> and / or
243 <application>Privoxy</application> are left on your
244 system. Check that no <application>Junkbuster</application>
245 or <application>Privoxy</application> objects are in
251 Then, just double-click the WarpIN self-installing archive, which will
252 guide you through the installation process. A shadow of the
253 <application>Privoxy</application> executable will be placed in your
254 startup folder so it will start automatically whenever OS/2 starts.
258 The directory you choose to install <application>Privoxy</application>
259 into will contain all of the configuration files.
263 <!-- ~~~~~ New section ~~~~~ -->
264 <sect3 id="installation-mac"><title>Mac OS X</title>
266 Installation instructions for the OS X platform depend upon whether
267 you downloaded a ready-built installation package (.pkg or .mpkg) or have
268 downloaded the source code.
271 <sect3 renderas="sect4" id="OS-X-install-from-package">
272 <title>Installation from ready-built package</title>
274 The downloaded file will either be a .pkg (for OS X 10.5 upwards) or a bzipped
275 .mpkg file (for OS X 10.4). The former can be double-clicked as is and the
276 installation will start; double-clicking the latter will unzip the .mpkg file
277 which can then be double-clicked to commence the installation.
280 The privoxy service will automatically start after a successful installation
281 (and thereafter every time your computer starts up) however you will need to
282 configure your web browser(s) to use it. To do so, configure them to use a
283 proxy for HTTP and HTTPS at the address 127.0.0.1:8118.
286 To prevent the privoxy service from automatically starting when your computer
287 starts up, remove or rename the file <literal>/Library/LaunchDaemons/org.ijbswa.privoxy.plist</literal>
288 (on OS X 10.5 and higher) or the folder named
289 <literal>/Library/StartupItems/Privoxy</literal> (on OS X 10.4 'Tiger').
292 To manually start or stop the privoxy service, use the scripts startPrivoxy.sh
293 and stopPrivoxy.sh supplied in /Applications/Privoxy. They must be run from an
294 administrator account, using sudo.
297 To uninstall, run /Applications/Privoxy/uninstall.command as sudo from an
298 administrator account.
301 <sect3 renderas="sect4" id="OS-X-install-from-source">
302 <title>Installation from source</title>
304 To build and install the Privoxy source code on OS X you will need to obtain
305 the macsetup module from the Privoxy Sourceforge CVS repository (refer to
306 Sourceforge help for details of how to set up a CVS client to have read-only
307 access to the repository). This module contains scripts that leverage the usual
308 open-source tools (available as part of Apple's free of charge Xcode
309 distribution or via the usual open-source software package managers for OS X
310 (MacPorts, Homebrew, Fink etc.) to build and then install the privoxy binary
311 and associated files. The macsetup module's README file contains complete
312 instructions for its use.
315 The privoxy service will automatically start after a successful installation
316 (and thereafter every time your computer starts up) however you will need to
317 configure your web browser(s) to use it. To do so, configure them to use a
318 proxy for HTTP and HTTPS at the address 127.0.0.1:8118.
321 To prevent the privoxy service from automatically starting when your computer
322 starts up, remove or rename the file <literal>/Library/LaunchDaemons/org.ijbswa.privoxy.plist</literal>
323 (on OS X 10.5 and higher) or the folder named
324 <literal>/Library/StartupItems/Privoxy</literal> (on OS X 10.4 'Tiger').
327 To manually start or stop the privoxy service, use the Privoxy Utility
328 for Mac OS X (also part of the macsetup module). This application can start
329 and stop the privoxy service and display its log and configuration files.
332 To uninstall, run the macsetup module's uninstall.sh as sudo from an
333 administrator account.
337 <!-- ~~~~~ New section ~~~~~ -->
338 <sect3 id="installation-freebsd"><title>FreeBSD</title>
341 Privoxy is part of FreeBSD's Ports Collection, you can build and install
342 it with <literal>cd /usr/ports/www/privoxy; make install clean</literal>.
348 <!-- ~~~~~ New section ~~~~~ -->
349 <sect2 id="installation-source"><title>Building from Source</title>
352 The most convenient way to obtain the <application>Privoxy</application> sources
353 is to download the source tarball from our
354 <ulink url="http://sourceforge.net/project/showfiles.php?group_id=11118&package_id=10571">project download
359 If you like to live on the bleeding edge and are not afraid of using
360 possibly unstable development versions, you can check out the up-to-the-minute
361 version directly from <ulink url="http://sourceforge.net/cvs/?group_id=11118">the
362 CVS repository</ulink>.
364 deprecated...out of business.
365 or simply download <ulink
366 url="http://cvs.sourceforge.net/cvstarballs/ijbswa-cvsroot.tar.bz2">the nightly CVS
371 <!-- include buildsource.sgml boilerplate: -->
373 <!-- end boilerplate -->
376 <!-- ~~~~~ New section ~~~~~ -->
377 <sect2 id="installation-keepupdated"><title>Keeping your Installation Up-to-Date</title>
380 If you wish to receive an email notification whenever we release updates of
381 <application>Privoxy</application> or the actions file, <ulink
382 url="http://lists.sourceforge.net/lists/listinfo/ijbswa-announce/">subscribe
383 to our announce mailing list</ulink>, ijbswa-announce@lists.sourceforge.net.
387 In order not to lose your personal changes and adjustments when updating
388 to the latest <literal>default.action</literal> file we <emphasis>strongly
389 recommend</emphasis> that you use <literal>user.action</literal> and
390 <literal>user.filter</literal> for your local
391 customizations of <application>Privoxy</application>. See the <link
392 linkend="actions-file">Chapter on actions files</link> for details.
400 <!-- ~ End section ~ -->
402 <!-- ~~~~~ New section ~~~~~ -->
403 <sect1 id="whatsnew">
404 <title>What's New in this Release</title>
408 <!-- ~~~~~ New section ~~~~~ -->
410 <sect2 id="upgradersnote">
411 <title>Note to Upgraders</title>
414 A quick list of things to be aware of before upgrading from earlier
415 versions of <application>Privoxy</application>:
423 The recommended way to upgrade &my-app; is to backup your old
424 configuration files, install the new ones, verify that &my-app;
425 is working correctly and finally merge back your changes using
426 <application>diff</application> and maybe <application>patch</application>.
429 There are a number of new features in each &my-app; release and
430 most of them have to be explicitly enabled in the configuration
431 files. Old configuration files obviously don't do that and due
432 to syntax changes using old configuration files with a new
433 &my-app; isn't always possible anyway.
438 Note that some installers remove earlier versions completely,
439 including configuration files, therefore you should really save
440 any important configuration files!
445 On the other hand, other installers don't overwrite existing configuration
446 files, thinking you will want to do that yourself.
451 In the default configuration only fatal errors are logged now.
452 You can change that in the <link linkend="DEBUG">debug section</link>
453 of the configuration file. You may also want to enable more verbose
454 logging until you verified that the new &my-app; version is working
461 Three other config file settings are now off by default:
462 <link linkend="enable-remote-toggle">enable-remote-toggle</link>,
463 <link linkend="enable-remote-http-toggle">enable-remote-http-toggle</link>,
464 and <link linkend="enable-edit-actions">enable-edit-actions</link>.
465 If you use or want these, you will need to explicitly enable them, and
466 be aware of the security issues involved.
473 What constitutes a <quote>default</quote> configuration has changed,
474 and you may want to review which actions are <quote>on</quote> by
475 default. This is primarily a matter of emphasis, but some features
476 you may have been used to, may now be <quote>off</quote> by default.
477 There are also a number of new actions and filters you may want to
478 consider, most of which are not fully incorporated into the default
479 settings as yet (see above).
486 The default actions setting is now <literal>Cautious</literal>. Previous
487 releases had a default setting of <literal>Medium</literal>. Experienced
488 users may want to adjust this, as it is fairly conservative by &my-app;
489 standards and past practices. See <ulink
490 url="http://config.privoxy.org/edit-actions-list?f=default">
491 http://config.privoxy.org/edit-actions-list?f=default</ulink>. New users
492 should try the default settings for a while before turning up the volume.
498 The default setting has filtering turned <emphasis>off</emphasis>, which
499 subsequently means that compression is <emphasis>on</emphasis>. Remember
500 that filtering does not work on compressed pages, so if you use, or want to
501 use, filtering, you will need to force compression off. Example:
505 { +<link linkend="filter">filter</link>{google} +<link linkend="prevent-compression">prevent-compression</link> }
509 Or if you use a number of filters, or filter many sites, you may just want
510 to turn off compression for all sites in
511 <filename>default.action</filename> (or
512 <filename>user.action</filename>).
519 Also, <link linkend="SESSION-COOKIES-ONLY">session-cookies-only</link> is
520 off by default now. If you've liked this feature in the past, you may want
521 to turn it back on in <filename>user.action</filename> now.
528 Some installers may not automatically start
529 <application>Privoxy</application> after installation.
540 <!-- ~~~~~ New section ~~~~~ -->
541 <sect1 id="quickstart"><title>Quickstart to Using Privoxy</title>
547 Install <application>Privoxy</application>. See the <link
548 linkend="installation">Installation Section</link> below for platform specific
555 Advanced users and those who want to offer <application>Privoxy</application>
556 service to more than just their local machine should check the <link
557 linkend="config">main config file</link>, especially the <link
558 linkend="access-control">security-relevant</link> options. These are
565 Start <application>Privoxy</application>, if the installation program has
566 not done this already (may vary according to platform). See the section
567 <link linkend="startup">Starting <application>Privoxy</application></link>.
573 Set your browser to use <application>Privoxy</application> as HTTP and
574 HTTPS (SSL) <ulink url="http://en.wikipedia.org/wiki/Proxy_server">proxy</ulink>
575 by setting the proxy configuration for address of
576 <literal>127.0.0.1</literal> and port <literal>8118</literal>.
577 <emphasis>DO NOT</emphasis> activate proxying for <literal>FTP</literal> or
578 any protocols besides HTTP and HTTPS (SSL) unless you intend to prevent your
579 browser from using these protocols.
585 Flush your browser's disk and memory caches, to remove any cached ad images.
586 If using <application>Privoxy</application> to manage
587 <ulink url="http://en.wikipedia.org/wiki/Browser_cookie">cookies</ulink>,
588 you should remove any currently stored cookies too.
594 A default installation should provide a reasonable starting point for
595 most. There will undoubtedly be occasions where you will want to adjust the
596 configuration, but that can be dealt with as the need arises. Little
597 to no initial configuration is required in most cases, you may want
599 <ulink url="config.html#ENABLE-EDIT-ACTIONS">web-based action editor</ulink> though.
600 Be sure to read the warnings first.
603 See the <link linkend="configuration">Configuration section</link> for more
604 configuration options, and how to customize your installation.
605 You might also want to look at the <link
606 linkend="quickstart-ad-blocking">next section</link> for a quick
607 introduction to how <application>Privoxy</application> blocks ads and
614 If you experience ads that slip through, innocent images that are
615 blocked, or otherwise feel the need to fine-tune
616 <application>Privoxy's</application> behavior, take a look at the <link
617 linkend="actions-file">actions files</link>. As a quick start, you might
618 find the <link linkend="act-examples">richly commented examples</link>
619 helpful. You can also view and edit the actions files through the <ulink
620 url="http://config.privoxy.org">web-based user interface</ulink>. The
621 Appendix <quote><link linkend="actionsanat">Troubleshooting: Anatomy of an
622 Action</link></quote> has hints on how to understand and debug actions that
623 <quote>misbehave</quote>.
628 Did anyone test these lately?
632 For easy access to &my-app;'s most important controls, drag the provided
633 <link linkend="bookmarklets">Bookmarklets</link> into your browser's
641 Please see the section <link linkend="contact">Contacting the
642 Developers</link> on how to report bugs, problems with websites or to get
649 Now enjoy surfing with enhanced control, comfort and privacy!
657 <!-- ~~~~~ New section ~~~~~ -->
659 <sect2 id="quickstart-ad-blocking">
660 <title>Quickstart to Ad Blocking</title>
662 NOTE: This section is deliberately redundant for those that don't
663 want to read the whole thing (which is getting lengthy).
666 Ad blocking is but one of <application>Privoxy's</application>
667 array of features. Many of these features are for the technically minded advanced
668 user. But, ad and banner blocking is surely common ground for everybody.
671 This section will provide a quick summary of ad blocking so
672 you can get up to speed quickly without having to read the more extensive
673 information provided below, though this is highly recommended.
676 First a bit of a warning ... blocking ads is much like blocking SPAM: the
677 more aggressive you are about it, the more likely you are to block
678 things that were not intended. And the more likely that some things
679 may not work as intended. So there is a trade off here. If you want
680 extreme ad free browsing, be prepared to deal with more
681 <quote>problem</quote> sites, and to spend more time adjusting the
682 configuration to solve these unintended consequences. In short, there is
683 not an easy way to eliminate <emphasis>all</emphasis> ads. Either take
684 the easy way and settle for <emphasis>most</emphasis> ads blocked with the
685 default configuration, or jump in and tweak it for your personal surfing
686 habits and preferences.
689 Secondly, a brief explanation of <application>Privoxy's </application>
690 <quote>actions</quote>. <quote>Actions</quote> in this context, are
691 the directives we use to tell <application>Privoxy</application> to perform
692 some task relating to HTTP transactions (i.e. web browsing). We tell
693 <application>Privoxy</application> to take some <quote>action</quote>. Each
694 action has a unique name and function. While there are many potential
695 <application>actions</application> in <application>Privoxy's</application>
696 arsenal, only a few are used for ad blocking. <link
697 linkend="actions">Actions</link>, and <link linkend="actions-file">action
698 configuration files</link>, are explained in depth below.
701 Actions are specified in <application>Privoxy's</application> configuration,
702 followed by one or more URLs to which the action should apply. URLs
703 can actually be URL type <link linkend="af-patterns">patterns</link> that use
704 wildcards so they can apply potentially to a range of similar URLs. The
705 actions, together with the URL patterns are called a section.
708 When you connect to a website, the full URL will either match one or more
709 of the sections as defined in <application>Privoxy's</application> configuration,
710 or not. If so, then <application>Privoxy</application> will perform the
711 respective actions. If not, then nothing special happens. Furthermore, web
712 pages may contain embedded, secondary URLs that your web browser will
713 use to load additional components of the page, as it parses the
714 original page's HTML content. An ad image for instance, is just an URL
715 embedded in the page somewhere. The image itself may be on the same server,
716 or a server somewhere else on the Internet. Complex web pages will have many
717 such embedded URLs. &my-app; can deal with each URL individually, so, for
718 instance, the main page text is not touched, but images from such-and-such
723 The most important actions for basic ad blocking are: <literal><link
724 linkend="block">block</link></literal>, <literal><link
725 linkend="handle-as-image">handle-as-image</link></literal>,
727 linkend="handle-as-empty-document">handle-as-empty-document</link></literal>,and
728 <literal><link linkend="set-image-blocker">set-image-blocker</link></literal>:
736 <literal><link linkend="block">block</link></literal> - this is perhaps
737 the single most used action, and is particularly important for ad blocking.
738 This action stops any contact between your browser and any URL patterns
739 that match this action's configuration. It can be used for blocking ads,
740 but also anything that is determined to be unwanted. By itself, it simply
741 stops any communication with the remote server and sends
742 <application>Privoxy</application>'s own built-in BLOCKED page instead to
743 let you now what has happened (with some exceptions, see below).
749 <literal><link linkend="handle-as-image">handle-as-image</link></literal> -
750 tells <application>Privoxy</application> to treat this URL as an image.
751 <application>Privoxy</application>'s default configuration already does this
752 for all common image types (e.g. GIF), but there are many situations where this
753 is not so easy to determine. So we'll force it in these cases. This is particularly
754 important for ad blocking, since only if we know that it's an image of
755 some kind, can we replace it with an image of our choosing, instead of the
756 <application>Privoxy</application> BLOCKED page (which would only result in
757 a <quote>broken image</quote> icon). There are some limitations to this
758 though. For instance, you can't just brute-force an image substitution for
759 an entire HTML page in most situations.
765 <literal><link linkend="handle-as-empty-document">handle-as-empty-document</link></literal> -
766 sends an empty document instead of <application>Privoxy's</application>
767 normal BLOCKED HTML page. This is useful for file types that are neither
768 HTML nor images, such as blocking JavaScript files.
775 linkend="set-image-blocker">set-image-blocker</link></literal> - tells
776 <application>Privoxy</application> what to display in place of an ad image that
777 has hit a block rule. For this to come into play, the URL must match a
778 <literal><link linkend="block">block</link></literal> action somewhere in the
779 configuration, <emphasis>and</emphasis>, it must also match an
780 <literal><link linkend="handle-as-image">handle-as-image</link></literal> action.
783 The configuration options on what to display instead of the ad are:
787 <emphasis>pattern</emphasis> - a checkerboard pattern, so that an ad
788 replacement is obvious. This is the default.
793 <emphasis>blank</emphasis> - A very small empty GIF image is displayed.
794 This is the so-called <quote>invisible</quote> configuration option.
799 <emphasis>http://<URL></emphasis> - A redirect to any image anywhere
800 of the user's choosing (advanced usage).
809 Advanced users will eventually want to explore &my-app;
810 <literal><link linkend="filter">filters</link></literal> as well. Filters
811 are very different from <literal><link
812 linkend="block">blocks</link></literal>.
813 A <quote>block</quote> blocks a site, page, or unwanted contented. Filters
814 are a way of filtering or modifying what is actually on the page. An example
815 filter usage: a text replacement of <quote>no-no</quote> for
816 <quote>nasty-word</quote>. That is a very simple example. This process can be
817 used for ad blocking, but it is more in the realm of advanced usage and has
818 some pitfalls to be wary off.
822 The quickest way to adjust any of these settings is with your browser through
823 the special <application>Privoxy</application> editor at <ulink
824 url="http://config.privoxy.org/show-status">http://config.privoxy.org/show-status</ulink>
825 (shortcut: <ulink url="http://p.p/">http://p.p/show-status</ulink>). This
826 is an internal page, and does not require Internet access.
830 Note that as of <application>Privoxy</application> 3.0.7 beta the
831 action editor is disabled by default. Check the
832 <ulink url="config.html#ENABLE-EDIT-ACTIONS">enable-edit-actions
833 section in the configuration file</ulink> to learn why and in which
834 cases it's safe to enable again.
838 If you decided to enable the action editor, select the appropriate
839 <quote>actions</quote> file, and click
840 <quote><guibutton>Edit</guibutton></quote>. It is best to put personal or
841 local preferences in <filename>user.action</filename> since this is not
842 meant to be overwritten during upgrades, and will over-ride the settings in
843 other files. Here you can insert new <quote>actions</quote>, and URLs for ad
844 blocking or other purposes, and make other adjustments to the configuration.
845 <application>Privoxy</application> will detect these changes automatically.
849 A quick and simple step by step example:
857 Right click on the ad image to be blocked, then select
858 <quote><guimenuitem>Copy Link Location</guimenuitem></quote> from the
866 url="http://config.privoxy.org/show-status">http://config.privoxy.org/show-status</ulink>
871 Find <filename>user.action</filename> in the top section, and click
872 on <quote><guibutton>Edit</guibutton></quote>:
875 <!-- image of editor and actions files selections -->
877 <figure pgwide="0" float="0"><title>Actions Files in Use</title>
880 <imagedata fileref="files-in-use.jpg" format="jpg">
883 <phrase>[ Screenshot of Actions Files in Use ]</phrase>
892 You should have a section with only
893 <literal><link linkend="block">block</link></literal> listed under
894 <quote>Actions:</quote>.
895 If not, click a <quote><guibutton>Insert new section below</guibutton></quote>
896 button, and in the new section that just appeared, click the
897 <guibutton>Edit</guibutton> button right under the word <quote>Actions:</quote>.
898 This will bring up a list of all actions. Find
899 <literal><link linkend="block">block</link></literal> near the top, and click
900 in the <quote>Enabled</quote> column, then <quote><guibutton>Submit</guibutton></quote>
906 Now, in the <literal><link linkend="block">block</link></literal> actions section,
907 click the <quote><guibutton>Add</guibutton></quote> button, and paste the URL the
908 browser got from <quote><guimenuitem>Copy Link Location</guimenuitem></quote>.
909 Remove the <literal>http://</literal> at the beginning of the URL. Then, click
910 <quote><guibutton>Submit</guibutton></quote> (or
911 <quote><guibutton>OK</guibutton></quote> if in a pop-up window).
916 Now go back to the original page, and press <keycap>SHIFT-Reload</keycap>
917 (or flush all browser caches). The image should be gone now.
925 This is a very crude and simple example. There might be good reasons to use a
926 wildcard pattern match to include potentially similar images from the same
927 site. For a more extensive explanation of <quote>patterns</quote>, and
928 the entire actions concept, see <link linkend="actions-file">the Actions
933 For advanced users who want to hand edit their config files, you might want
934 to now go to the <link linkend="act-examples">Actions Files Tutorial</link>.
935 The ideas explained therein also apply to the web-based editor.
938 There are also various
939 <link linkend="filter">filters</link> that can be used for ad blocking
940 (filters are a special subset of actions). These
941 fall into the <quote>advanced</quote> usage category, and are explained in
942 depth in later sections.
949 <!-- ~ End section ~ -->
952 <!-- ~~~~~ New section ~~~~~ -->
954 <title>Starting Privoxy</title>
956 Before launching <application>Privoxy</application> for the first time, you
957 will want to configure your browser(s) to use
958 <application>Privoxy</application> as a HTTP and HTTPS (SSL)
959 <ulink url="http://en.wikipedia.org/wiki/Proxy_server">proxy</ulink>. The default is
960 127.0.0.1 (or localhost) for the proxy address, and port 8118 (earlier versions
961 used port 8000). This is the one configuration step <emphasis>that must be done
965 Please note that <application>Privoxy</application> can only proxy HTTP and
966 HTTPS traffic. It will not work with FTP or other protocols.
969 <!-- image of Mozilla Proxy configuration -->
971 <figure pgwide="0" float="0"><title>Proxy Configuration Showing
972 Mozilla/Netscape HTTP and HTTPS (SSL) Settings</title>
975 <imagedata fileref="proxy_setup.jpg" format="jpg">
978 <phrase>[ Screenshot of Mozilla Proxy Configuration ]</phrase>
986 With <application>Firefox</application>, this is typically set under:
990 <guibutton>Tools</guibutton> -> <guibutton>Options</guibutton> -> <guibutton>Advanced</guibutton> -> <guibutton>Network</guibutton> -><guibutton>Connection</guibutton> -> <guibutton>Settings</guibutton>
995 Or optionally on some platforms:
999 <guibutton>Edit</guibutton> -> <guibutton>Preferences</guibutton> -> <guibutton>General</guibutton> -> <guibutton>Connection Settings</guibutton> -> <guibutton>Manual Proxy Configuration</guibutton>
1005 With <application>Netscape</application> (and
1006 <application>Mozilla</application>), this can be set under:
1011 <!-- Mix ascii and gui art, something for everybody -->
1012 <!-- spacing on this is tricky -->
1013 <guibutton>Edit</guibutton> -> <guibutton>Preferences</guibutton> -> <guibutton>Advanced</guibutton> -> <guibutton>Proxies</guibutton> -> <guibutton>HTTP Proxy</guibutton>
1018 For <application>Internet Explorer v.5-7</application>:
1022 <guibutton>Tools</guibutton> -> <guibutton>Internet Options</guibutton> -> <guibutton>Connections</guibutton> -> <guibutton>LAN Settings</guibutton>
1026 Then, check <quote>Use Proxy</quote> and fill in the appropriate info
1027 (Address: 127.0.0.1, Port: 8118). Include HTTPS (SSL), if you want HTTPS
1028 proxy support too (sometimes labeled <quote>Secure</quote>). Make sure any
1029 checkboxes like <quote>Use the same proxy server for all protocols</quote> is
1030 <emphasis>UNCHECKED</emphasis>. You want only HTTP and HTTPS (SSL)!
1033 <!-- image of IE Proxy configuration -->
1035 <figure pgwide="0" float="0"><title>Proxy Configuration Showing
1036 Internet Explorer HTTP and HTTPS (Secure) Settings</title>
1039 <imagedata fileref="proxy2.jpg" format="jpg">
1042 <phrase>[ Screenshot of IE Proxy Configuration ]</phrase>
1050 After doing this, flush your browser's disk and memory caches to force a
1051 re-reading of all pages and to get rid of any ads that may be cached. Remove
1052 any <ulink url="http://en.wikipedia.org/wiki/Browser_cookie">cookies</ulink>,
1053 if you want <application>Privoxy</application> to manage that. You are now
1054 ready to start enjoying the benefits of using
1055 <application>Privoxy</application>!
1059 <application>Privoxy</application> itself is typically started by specifying the
1060 main configuration file to be used on the command line. If no configuration
1061 file is specified on the command line, <application>Privoxy</application>
1062 will look for a file named <filename>config</filename> in the current
1063 directory. Except on Win32 where it will try <filename>config.txt</filename>.
1066 <sect2 id="start-debian">
1067 <title>Debian</title>
1069 We use a script. Note that Debian typically starts &my-app; upon booting per
1070 default. It will use the file
1071 <filename>/etc/privoxy/config</filename> as its main configuration
1076 # /etc/init.d/privoxy start
1081 <sect2 id="start-windows">
1082 <title>Windows</title>
1084 Click on the &my-app; Icon to start <application>Privoxy</application>. If no configuration file is
1085 specified on the command line, <application>Privoxy</application> will look
1086 for a file named <filename>config.txt</filename>. Note that Windows will
1087 automatically start &my-app; when the system starts if you chose that option
1091 <application>Privoxy</application> can run with full Windows service functionality.
1092 On Windows only, the &my-app; program has two new command line arguments
1093 to install and uninstall &my-app; as a service. See the
1094 <link linkend="installation-pack-win">Windows Installation
1095 instructions</link> for details.
1099 <sect2 id="start-unices">
1100 <title>Solaris, NetBSD, FreeBSD, HP-UX and others</title>
1102 Example Unix startup command:
1106 # /usr/sbin/privoxy /etc/privoxy/config
1111 <sect2 id="start-os2">
1114 During installation, <application>Privoxy</application> is configured to
1115 start automatically when the system restarts. You can start it manually by
1116 double-clicking on the <application>Privoxy</application> icon in the
1117 <application>Privoxy</application> folder.
1121 <sect2 id="start-macosx">
1122 <title>Mac OS X</title>
1124 After downloading the privoxy software, unzip the downloaded file by
1125 double-clicking on the zip file icon. Then, double-click on the
1126 installer package icon and follow the installation process.
1129 The privoxy service will automatically start after a successful
1130 installation. In addition, the privoxy service will automatically
1131 start every time your computer starts up.
1134 To prevent the privoxy service from automatically starting when your
1135 computer starts up, remove or rename the folder named
1136 /Library/StartupItems/Privoxy.
1139 A simple application named Privoxy Utility has been created which
1140 enables administrators to easily start and stop the privoxy service.
1143 In addition, the Privoxy Utility presents a simple way for
1144 administrators to edit the various privoxy config files. A method
1145 to uninstall the software is also available.
1148 An administrator username and password must be supplied in order for
1149 the Privoxy Utility to perform any of the tasks.
1157 See the section <link linkend="cmdoptions">Command line options</link> for
1161 must find a better place for this paragraph
1164 The included default configuration files should give a reasonable starting
1165 point. Most of the per site configuration is done in the
1166 <ulink url="actions-file.html"><quote>actions</quote></ulink> files. These are
1167 where various cookie actions are defined, ad and banner blocking, and other
1168 aspects of <application>Privoxy</application> configuration. There are several
1169 such files included, with varying levels of aggressiveness.
1173 You will probably want to keep an eye out for sites for which you may prefer
1174 persistent cookies, and add these to your actions configuration as needed. By
1175 default, most of these will be accepted only during the current browser
1176 session (aka <quote>session cookies</quote>), unless you add them to the
1177 configuration. If you want the browser to handle this instead, you will need
1178 to edit <filename>user.action</filename> (or through the web based interface)
1179 and disable this feature. If you use more than one browser, it would make
1180 more sense to let <application>Privoxy</application> handle this. In which
1181 case, the browser(s) should be set to accept all cookies.
1185 Another feature where you will probably want to define exceptions for trusted
1186 sites is the popup-killing (through <ulink
1187 url="actions-file.html#FILTER-POPUPS"><quote>+filter{popups}</quote></ulink>),
1188 because your favorite shopping, banking, or leisure site may need
1189 popups (explained below).
1193 <application>Privoxy</application> does not support all of the optional HTTP/1.1
1194 features yet. In the unlikely event that you experience inexplicable problems
1195 with browsers that use HTTP/1.1 per default
1196 (like <application>Mozilla</application> or recent versions of I.E.), you might
1197 try to force HTTP/1.0 compatibility. For Mozilla, look under <literal>Edit ->
1198 Preferences -> Debug -> Networking</literal>.
1199 Alternatively, set the <quote>+downgrade-http-version</quote> config option in
1200 <filename>default.action</filename> which will downgrade your browser's HTTP
1201 requests from HTTP/1.1 to HTTP/1.0 before processing them.
1205 After running <application>Privoxy</application> for a while, you can
1206 start to fine tune the configuration to suit your personal, or site,
1207 preferences and requirements. There are many, many aspects that can
1208 be customized. <quote>Actions</quote>
1209 can be adjusted by pointing your browser to
1210 <ulink url="http://config.privoxy.org/">http://config.privoxy.org/</ulink>
1211 (shortcut: <ulink url="http://p.p/">http://p.p/</ulink>),
1212 and then follow the link to <quote>View & Change the Current Configuration</quote>.
1213 (This is an internal page and does not require Internet access.)
1217 In fact, various aspects of <application>Privoxy</application>
1218 configuration can be viewed from this page, including
1219 current configuration parameters, source code version numbers,
1220 the browser's request headers, and <quote>actions</quote> that apply
1221 to a given URL. In addition to the actions file
1222 editor mentioned above, <application>Privoxy</application> can also
1223 be turned <quote>on</quote> and <quote>off</quote> (toggled) from this page.
1227 If you encounter problems, try loading the page without
1228 <application>Privoxy</application>. If that helps, enter the URL where
1229 you have the problems into <ulink url="http://p.p/show-url-info">the browser
1230 based rule tracing utility</ulink>. See which rules apply and why, and
1231 then try turning them off for that site one after the other, until the problem
1232 is gone. When you have found the culprit, you might want to turn the rest on
1237 If the above paragraph sounds gibberish to you, you might want to <link
1238 linkend="actions-file">read more about the actions concept</link>
1239 or even dive deep into the <link linkend="actionsanat">Appendix
1244 If you can't get rid of the problem at all, think you've found a bug in
1245 Privoxy, want to propose a new feature or smarter rules, please see the
1246 section <link linkend="contact"><quote>Contacting the
1247 Developers</quote></link> below.
1252 <!-- ~~~~~ New section ~~~~~ -->
1253 <sect2 id="cmdoptions">
1254 <title>Command Line Options</title>
1256 <application>Privoxy</application> may be invoked with the following
1257 command-line options:
1265 <emphasis>--config-test</emphasis>
1268 Exit after loading the configuration files before binding to
1269 the listen address. The exit code signals whether or not the
1270 configuration files have been successfully loaded.
1273 If the exit code is 1, at least one of the configuration files
1274 is invalid, if it is 0, all the configuration files have been
1275 successfully loaded (but may still contain errors that can
1276 currently only be detected at run time).
1279 This option doesn't affect the log setting, combination with
1280 <emphasis>--no-daemon</emphasis> is recommended if a configured
1281 log file shouldn't be used.
1286 <emphasis>--version</emphasis>
1289 Print version info and exit. Unix only.
1294 <emphasis>--help</emphasis>
1297 Print short usage info and exit. Unix only.
1302 <emphasis>--no-daemon</emphasis>
1305 Don't become a daemon, i.e. don't fork and become process group
1306 leader, and don't detach from controlling tty. Unix only.
1311 <emphasis>--pidfile FILE</emphasis>
1314 On startup, write the process ID to <emphasis>FILE</emphasis>. Delete the
1315 <emphasis>FILE</emphasis> on exit. Failure to create or delete the
1316 <emphasis>FILE</emphasis> is non-fatal. If no <emphasis>FILE</emphasis>
1317 option is given, no PID file will be used. Unix only.
1322 <emphasis>--user USER[.GROUP]</emphasis>
1325 After (optionally) writing the PID file, assume the user ID of
1326 <emphasis>USER</emphasis>, and if included the GID of GROUP. Exit if the
1327 privileges are not sufficient to do so. Unix only.
1332 <emphasis>--chroot</emphasis>
1335 Before changing to the user ID given in the <emphasis>--user</emphasis> option,
1336 chroot to that user's home directory, i.e. make the kernel pretend to the &my-app;
1337 process that the directory tree starts there. If set up carefully, this can limit
1338 the impact of possible vulnerabilities in &my-app; to the files contained in that hierarchy.
1344 <emphasis>--pre-chroot-nslookup hostname</emphasis>
1347 Specifies a hostname to look up before doing a chroot. On some systems, initializing the
1348 resolver library involves reading config files from /etc and/or loading additional shared
1349 libraries from /lib. On these systems, doing a hostname lookup before the chroot reduces
1350 the number of files that must be copied into the chroot tree.
1353 For fastest startup speed, a good value is a hostname that is not in /etc/hosts but that
1354 your local name server (listed in /etc/resolv.conf) can resolve without recursion
1355 (that is, without having to ask any other name servers). The hostname need not exist,
1356 but if it doesn't, an error message (which can be ignored) will be output.
1362 <emphasis>configfile</emphasis>
1365 If no <emphasis>configfile</emphasis> is included on the command line,
1366 <application>Privoxy</application> will look for a file named
1367 <quote>config</quote> in the current directory (except on Win32
1368 where it will look for <quote>config.txt</quote> instead). Specify
1369 full path to avoid confusion. If no config file is found,
1370 <application>Privoxy</application> will fail to start.
1378 On <application>MS Windows</application> only there are two additional
1379 command-line options to allow <application>Privoxy</application> to install and
1380 run as a <emphasis>service</emphasis>. See the
1381 <link linkend="installation-pack-win">Window Installation section</link>
1389 <!-- ~ End section ~ -->
1392 <!-- ~~~~~ New section ~~~~~ -->
1393 <sect1 id="configuration"><title>Privoxy Configuration</title>
1395 All <application>Privoxy</application> configuration is stored
1396 in text files. These files can be edited with a text editor.
1397 Many important aspects of <application>Privoxy</application> can
1398 also be controlled easily with a web browser.
1402 <!-- ~~~~~ New section ~~~~~ -->
1405 <title>Controlling Privoxy with Your Web Browser</title>
1407 <application>Privoxy</application>'s user interface can be reached through the special
1408 URL <ulink url="http://config.privoxy.org/">http://config.privoxy.org/</ulink>
1409 (shortcut: <ulink url="http://p.p/">http://p.p/</ulink>),
1410 which is a built-in page and works without Internet access.
1411 You will see the following section:
1415 <!-- Needs to be put in a table and colorized -->
1418 <bridgehead renderas="sect2"> Privoxy Menu</bridgehead>
1422 ▪ <ulink url="http://config.privoxy.org/show-status">View & change the current configuration</ulink>
1425 ▪ <ulink url="http://config.privoxy.org/show-version">View the source code version numbers</ulink>
1428 ▪ <ulink url="http://config.privoxy.org/show-request">View the request headers.</ulink>
1431 ▪ <ulink url="http://config.privoxy.org/show-url-info">Look up which actions apply to a URL and why</ulink>
1434 ▪ <ulink url="http://config.privoxy.org/toggle">Toggle Privoxy on or off</ulink>
1437 ▪ <ulink
1438 url="http://www.privoxy.org/&p-version;/user-manual/">Documentation</ulink>
1446 This should be self-explanatory. Note the first item leads to an editor for the
1447 <link linkend="actions-file">actions files</link>, which is where the ad, banner,
1448 cookie, and URL blocking magic is configured as well as other advanced features of
1449 <application>Privoxy</application>. This is an easy way to adjust various
1450 aspects of <application>Privoxy</application> configuration. The actions
1451 file, and other configuration files, are explained in detail below.
1455 <quote>Toggle Privoxy On or Off</quote> is handy for sites that might
1456 have problems with your current actions and filters. You can in fact use
1457 it as a test to see whether it is <application>Privoxy</application>
1458 causing the problem or not. <application>Privoxy</application> continues
1459 to run as a proxy in this case, but all manipulation is disabled, i.e.
1460 <application>Privoxy</application> acts like a normal forwarding proxy. There
1461 is even a toggle <link linkend="bookmarklets">Bookmarklet</link> offered, so
1462 that you can toggle <application>Privoxy</application> with one click from
1467 Note that several of the features described above are disabled by default
1468 in <application>Privoxy</application> 3.0.7 beta and later.
1470 <ulink url="config.html">configuration file</ulink> to learn why
1471 and in which cases it's safe to enable them again.
1476 <!-- ~ End section ~ -->
1481 <!-- ~~~~~ New section ~~~~~ -->
1483 <sect2 id="confoverview">
1484 <title>Configuration Files Overview</title>
1486 For Unix, *BSD and Linux, all configuration files are located in
1487 <filename>/etc/privoxy/</filename> by default. For MS Windows, OS/2, and
1488 AmigaOS these are all in the same directory as the
1489 <application>Privoxy</application> executable. <![%p-not-stable;[ The name
1490 and number of configuration files has changed from previous versions, and is
1491 subject to change as development progresses.]]>
1495 The installed defaults provide a reasonable starting point, though
1496 some settings may be aggressive by some standards. For the time being, the
1497 principle configuration files are:
1505 The <link linkend="config">main configuration file</link> is named <filename>config</filename>
1506 on Linux, Unix, BSD, OS/2, and AmigaOS and <filename>config.txt</filename>
1507 on Windows. This is a required file.
1513 <filename>match-all.action</filename> is used to define which <quote>actions</quote>
1514 relating to banner-blocking, images, pop-ups, content modification, cookie handling
1515 etc should be applied by default. It should be the first actions file loaded.
1518 <filename>default.action</filename> defines many exceptions (both positive and negative)
1519 from the default set of actions that's configured in <filename>match-all.action</filename>.
1520 It should be the second actions file loaded and shouldn't be edited by the user.
1523 Multiple actions files may be defined in <filename>config</filename>. These
1524 are processed in the order they are defined. Local customizations and locally
1525 preferred exceptions to the default policies as defined in
1526 <filename>match-all.action</filename> (which you will most probably want
1527 to define sooner or later) are best applied in <filename>user.action</filename>,
1528 where you can preserve them across upgrades. The file isn't installed by all
1529 installers, but you can easily create it yourself with a text editor.
1532 There is also a web based editor that can be accessed from
1534 url="http://config.privoxy.org/show-status">http://config.privoxy.org/show-status</ulink>
1536 url="http://p.p/show-status">http://p.p/show-status</ulink>) for the
1537 various actions files.
1543 <quote>Filter files</quote> (the <link linkend="filter-file">filter
1544 file</link>) can be used to re-write the raw page content, including
1545 viewable text as well as embedded HTML and JavaScript, and whatever else
1546 lurks on any given web page. The filtering jobs are only pre-defined here;
1547 whether to apply them or not is up to the actions files.
1548 <filename>default.filter</filename> includes various filters made
1549 available for use by the developers. Some are much more intrusive than
1550 others, and all should be used with caution. You may define additional
1551 filter files in <filename>config</filename> as you can with
1552 actions files. We suggest <filename>user.filter</filename> for any
1553 locally defined filters or customizations.
1561 The syntax of the configuration and filter files may change between different
1562 Privoxy versions, unfortunately some enhancements cost backwards compatibility.
1563 <!-- Add link to documentation-->
1567 All files use the <quote><literal>#</literal></quote> character to denote a
1568 comment (the rest of the line will be ignored) and understand line continuation
1569 through placing a backslash ("<literal>\</literal>") as the very last character
1570 in a line. If the <literal>#</literal> is preceded by a backslash, it looses
1571 its special function. Placing a <literal>#</literal> in front of an otherwise
1572 valid configuration line to prevent it from being interpreted is called "commenting
1573 out" that line. Blank lines are ignored.
1577 The actions files and filter files
1578 can use Perl style <link linkend="regex">regular expressions</link> for
1579 maximum flexibility.
1583 After making any changes, there is no need to restart
1584 <application>Privoxy</application> in order for the changes to take
1585 effect. <application>Privoxy</application> detects such changes
1586 automatically. Note, however, that it may take one or two additional
1587 requests for the change to take effect. When changing the listening address
1588 of <application>Privoxy</application>, these <quote>wake up</quote> requests
1589 must obviously be sent to the <emphasis>old</emphasis> listening address.
1594 While under development, the configuration content is subject to change.
1595 The below documentation may not be accurate by the time you read this.
1596 Also, what constitutes a <quote>default</quote> setting, may change, so
1597 please check all your configuration files on important issues.
1603 <!-- ~ End section ~ -->
1606 <!-- ~~~~~~~~ New section Header ~~~~~~~~~ -->
1608 <!-- **************************************************** -->
1609 <!-- Include config.sgml here -->
1610 <!-- This is where the entire config file is detailed. -->
1612 <!-- end include -->
1615 <!-- ~ End section ~ -->
1619 <!-- ~~~~~~~~ New section Header ~~~~~~~~~ -->
1621 <sect1 id="actions-file"><title>Actions Files</title>
1625 XXX: similar descriptions are in the Configuration Files sections.
1626 We should only describe them at one place.
1629 The actions files are used to define what <emphasis>actions</emphasis>
1630 <application>Privoxy</application> takes for which URLs, and thus determines
1631 how ad images, cookies and various other aspects of HTTP content and
1632 transactions are handled, and on which sites (or even parts thereof).
1633 There are a number of such actions, with a wide range of functionality.
1634 Each action does something a little different.
1635 These actions give us a veritable arsenal of tools with which to exert
1636 our control, preferences and independence. Actions can be combined so that
1637 their effects are aggregated when applied against a given set of URLs.
1641 are three action files included with <application>Privoxy</application> with
1648 <filename>match-all.action</filename> - is used to define which
1649 <quote>actions</quote> relating to banner-blocking, images, pop-ups,
1650 content modification, cookie handling etc should be applied by default.
1651 It should be the first actions file loaded
1656 <filename>default.action</filename> - defines many exceptions (both
1657 positive and negative) from the default set of actions that's configured
1658 in <filename>match-all.action</filename>. It is a set of rules that should
1659 work reasonably well as-is for most users. This file is only supposed to
1660 be edited by the developers. It should be the second actions file loaded.
1665 <filename>user.action</filename> - is intended to be for local site
1666 preferences and exceptions. As an example, if your ISP or your bank
1667 has specific requirements, and need special handling, this kind of
1668 thing should go here. This file will not be upgraded.
1673 <guibutton>Edit</guibutton> <guibutton>Set to Cautious</guibutton> <guibutton>Set to Medium</guibutton> <guibutton>Set to Advanced</guibutton>
1676 These have increasing levels of aggressiveness <emphasis>and have no
1677 influence on your browsing unless you select them explicitly in the
1678 editor</emphasis>. A default installation should be pre-set to
1679 <literal>Cautious</literal>. New users should try this for a while before
1680 adjusting the settings to more aggressive levels. The more aggressive
1681 the settings, then the more likelihood there is of problems such as sites
1682 not working as they should.
1685 The <guibutton>Edit</guibutton> button allows you to turn each
1686 action on/off individually for fine-tuning. The <guibutton>Cautious</guibutton>
1687 button changes the actions list to low/safe settings which will activate
1688 ad blocking and a minimal set of &my-app;'s features, and subsequently
1689 there will be less of a chance for accidental problems. The
1690 <guibutton>Medium</guibutton> button sets the list to a medium level of
1691 other features and a low level set of privacy features. The
1692 <guibutton>Advanced</guibutton> button sets the list to a high level of
1693 ad blocking and medium level of privacy. See the chart below. The latter
1694 three buttons over-ride any changes via with the
1695 <guibutton>Edit</guibutton> button. More fine-tuning can be done in the
1696 lower sections of this internal page.
1699 While the actions file editor allows to enable these settings in all
1700 actions files, they are only supposed to be enabled in the first one
1701 to make sure you don't unintentionally overrule earlier rules.
1704 The default profiles, and their associated actions, as pre-defined in
1705 <filename>default.action</filename> are:
1708 <table frame=all><title>Default Configurations</title>
1709 <tgroup cols=4 align=left colsep=1 rowsep=1>
1710 <colspec colname=c1>
1711 <colspec colname=c2>
1712 <colspec colname=c3>
1713 <colspec colname=c4>
1716 <entry>Feature</entry>
1717 <entry>Cautious</entry>
1718 <entry>Medium</entry>
1719 <entry>Advanced</entry>
1724 <!-- <entry>f1</entry> -->
1725 <!-- <entry>f2</entry> -->
1726 <!-- <entry>f3</entry> -->
1727 <!-- <entry>f4</entry> -->
1733 <entry>Ad-blocking Aggressiveness</entry>
1734 <entry>medium</entry>
1740 <entry>Ad-filtering by size</entry>
1747 <entry>Ad-filtering by link</entry>
1753 <entry>Pop-up killing</entry>
1754 <entry>blocks only</entry>
1755 <entry>blocks only</entry>
1756 <entry>blocks only</entry>
1760 <entry>Privacy Features</entry>
1762 <entry>medium</entry>
1763 <entry>medium/high</entry>
1767 <entry>Cookie handling</entry>
1769 <entry>session-only</entry>
1774 <entry>Referer forging</entry>
1781 <entry>GIF de-animation</entry>
1788 <entry>Fast redirects</entry>
1795 <entry>HTML taming</entry>
1802 <entry>JavaScript taming</entry>
1809 <entry>Web-bug killing</entry>
1816 <entry>Image tag reordering</entry>
1832 The list of actions files to be used are defined in the main configuration
1833 file, and are processed in the order they are defined (e.g.
1834 <filename>default.action</filename> is typically processed before
1835 <filename>user.action</filename>). The content of these can all be viewed and
1837 url="http://config.privoxy.org/show-status">http://config.privoxy.org/show-status</ulink>.
1838 The over-riding principle when applying actions, is that the last action that
1839 matches a given URL wins. The broadest, most general rules go first
1840 (defined in <filename>default.action</filename>),
1841 followed by any exceptions (typically also in
1842 <filename>default.action</filename>), which are then followed lastly by any
1843 local preferences (typically in <emphasis>user</emphasis><filename>.action</filename>).
1844 Generally, <filename>user.action</filename> has the last word.
1848 An actions file typically has multiple sections. If you want to use
1849 <quote>aliases</quote> in an actions file, you have to place the (optional)
1850 <link linkend="aliases">alias section</link> at the top of that file.
1851 Then comes the default set of rules which will apply universally to all
1852 sites and pages (be <emphasis>very careful</emphasis> with using such a
1853 universal set in <filename>user.action</filename> or any other actions file after
1854 <filename>default.action</filename>, because it will override the result
1855 from consulting any previous file). And then below that,
1856 exceptions to the defined universal policies. You can regard
1857 <filename>user.action</filename> as an appendix to <filename>default.action</filename>,
1858 with the advantage that it is a separate file, which makes preserving your
1859 personal settings across <application>Privoxy</application> upgrades easier.
1863 Actions can be used to block anything you want, including ads, banners, or
1864 just some obnoxious URL whose content you would rather not see. Cookies can be accepted
1865 or rejected, or accepted only during the current browser session (i.e. not
1866 written to disk), content can be modified, some JavaScripts tamed, user-tracking
1867 fooled, and much more. See below for a <link linkend="actions">complete list
1871 <!-- ~~~~~ New section ~~~~~ -->
1873 <title>Finding the Right Mix</title>
1875 Note that some <link linkend="actions">actions</link>, like cookie suppression
1876 or script disabling, may render some sites unusable that rely on these
1877 techniques to work properly. Finding the right mix of actions is not always easy and
1878 certainly a matter of personal taste. And, things can always change, requiring
1879 refinements in the configuration. In general, it can be said that the more
1880 <quote>aggressive</quote> your default settings (in the top section of the
1881 actions file) are, the more exceptions for <quote>trusted</quote> sites you
1882 will have to make later. If, for example, you want to crunch all cookies per
1883 default, you'll have to make exceptions from that rule for sites that you
1884 regularly use and that require cookies for actually useful purposes, like maybe
1885 your bank, favorite shop, or newspaper.
1889 We have tried to provide you with reasonable rules to start from in the
1890 distribution actions files. But there is no general rule of thumb on these
1891 things. There just are too many variables, and sites are constantly changing.
1892 Sooner or later you will want to change the rules (and read this chapter again :).
1896 <!-- ~~~~~ New section ~~~~~ -->
1898 <title>How to Edit</title>
1900 The easiest way to edit the actions files is with a browser by
1901 using our browser-based editor, which can be reached from <ulink
1902 url="http://config.privoxy.org/show-status">http://config.privoxy.org/show-status</ulink>.
1903 Note: the config file option <link
1904 linkend="enable-edit-actions">enable-edit-actions</link> must be enabled for
1905 this to work. The editor allows both fine-grained control over every single
1906 feature on a per-URL basis, and easy choosing from wholesale sets of defaults
1907 like <quote>Cautious</quote>, <quote>Medium</quote> or
1908 <quote>Advanced</quote>. Warning: the <quote>Advanced</quote> setting is more
1909 aggressive, and will be more likely to cause problems for some sites.
1910 Experienced users only!
1914 If you prefer plain text editing to GUIs, you can of course also directly edit the
1915 the actions files with your favorite text editor. Look at
1916 <filename>default.action</filename> which is richly commented with many
1922 <sect2 id="actions-apply">
1923 <title>How Actions are Applied to Requests</title>
1925 Actions files are divided into sections. There are special sections,
1926 like the <quote><link linkend="aliases">alias</link></quote> sections which will
1927 be discussed later. For now let's concentrate on regular sections: They have a
1928 heading line (often split up to multiple lines for readability) which consist
1929 of a list of actions, separated by whitespace and enclosed in curly braces.
1930 Below that, there is a list of URL and tag patterns, each on a separate line.
1934 To determine which actions apply to a request, the URL of the request is
1935 compared to all URL patterns in each <quote>action file</quote>.
1936 Every time it matches, the list of applicable actions for the request is
1937 incrementally updated, using the heading of the section in which the
1938 pattern is located. The same is done again for tags and tag patterns later on.
1942 If multiple applying sections set the same action differently,
1943 the last match wins. If not, the effects are aggregated.
1944 E.g. a URL might match a regular section with a heading line of <literal>{
1945 +<link linkend="handle-as-image">handle-as-image</link> }</literal>,
1946 then later another one with just <literal>{
1947 +<link linkend="block">block</link> }</literal>, resulting
1948 in <emphasis>both</emphasis> actions to apply. And there may well be
1949 cases where you will want to combine actions together. Such a section then
1955 { +<literal>handle-as-image</literal> +<literal>block{Banner ads.}</literal> }
1956 # Block these as if they were images. Send no block page.
1958 media.example.com/.*banners
1959 .example.com/images/ads/</screen>
1963 You can trace this process for URL patterns and any given URL by visiting <ulink
1964 url="http://config.privoxy.org/show-url-info">http://config.privoxy.org/show-url-info</ulink>.
1968 Examples and more detail on this is provided in the Appendix, <link linkend="ACTIONSANAT">
1969 Troubleshooting: Anatomy of an Action</link> section.
1973 <!-- ~~~~~ New section ~~~~~ -->
1974 <sect2 id="af-patterns">
1975 <title>Patterns</title>
1977 As mentioned, <application>Privoxy</application> uses <quote>patterns</quote>
1978 to determine what <emphasis>actions</emphasis> might apply to which sites and
1979 pages your browser attempts to access. These <quote>patterns</quote> use wild
1980 card type <emphasis>pattern</emphasis> matching to achieve a high degree of
1981 flexibility. This allows one expression to be expanded and potentially match
1982 against many similar patterns.
1986 Generally, an URL pattern has the form
1987 <literal><domain><port>/<path></literal>, where the
1988 <literal><domain></literal>, the <literal><port></literal>
1989 and the <literal><path></literal> are optional. (This is why the special
1990 <literal>/</literal> pattern matches all URLs). Note that the protocol
1991 portion of the URL pattern (e.g. <literal>http://</literal>) should
1992 <emphasis>not</emphasis> be included in the pattern. This is assumed already!
1995 The pattern matching syntax is different for the domain and path parts of
1996 the URL. The domain part uses a simple globbing type matching technique,
1997 while the path part uses more flexible
1998 <ulink url="http://en.wikipedia.org/wiki/Regular_expressions"><quote>Regular
1999 Expressions</quote></ulink> (POSIX 1003.2).
2002 The port part of a pattern is a decimal port number preceded by a colon
2003 (<literal>:</literal>). If the domain part contains a numerical IPv6 address,
2004 it has to be put into angle brackets
2005 (<literal><</literal>, <literal>></literal>).
2010 <term><literal>www.example.com/</literal></term>
2013 is a domain-only pattern and will match any request to <literal>www.example.com</literal>,
2014 regardless of which document on that server is requested. So ALL pages in
2015 this domain would be covered by the scope of this action. Note that a
2016 simple <literal>example.com</literal> is different and would NOT match.
2021 <term><literal>www.example.com</literal></term>
2024 means exactly the same. For domain-only patterns, the trailing <literal>/</literal> may
2030 <term><literal>www.example.com/index.html</literal></term>
2033 matches all the documents on <literal>www.example.com</literal>
2034 whose name starts with <literal>/index.html</literal>.
2039 <term><literal>www.example.com/index.html$</literal></term>
2042 matches only the single document <literal>/index.html</literal>
2043 on <literal>www.example.com</literal>.
2048 <term><literal>/index.html$</literal></term>
2051 matches the document <literal>/index.html</literal>, regardless of the domain,
2052 i.e. on <emphasis>any</emphasis> web server anywhere.
2057 <term><literal>/</literal></term>
2060 Matches any URL because there's no requirement for either the
2061 domain or the path to match anything.
2066 <term><literal>:8000/</literal></term>
2069 Matches any URL pointing to TCP port 8000.
2074 <term><literal><2001:db8::1>/</literal></term>
2077 Matches any URL with the host address <literal>2001:db8::1</literal>.
2078 (Note that the real URL uses plain brackets, not angle brackets.)
2083 <term><literal>index.html</literal></term>
2086 matches nothing, since it would be interpreted as a domain name and
2087 there is no top-level domain called <literal>.html</literal>. So its
2095 <!-- ~~~~~ New section ~~~~~ -->
2096 <sect3><title>The Domain Pattern</title>
2099 The matching of the domain part offers some flexible options: if the
2100 domain starts or ends with a dot, it becomes unanchored at that end.
2106 <term><literal>.example.com</literal></term>
2109 matches any domain with first-level domain <literal>com</literal>
2110 and second-level domain <literal>example</literal>.
2111 For example <literal>www.example.com</literal>,
2112 <literal>example.com</literal> and <literal>foo.bar.baz.example.com</literal>.
2113 Note that it wouldn't match if the second-level domain was <literal>another-example</literal>.
2118 <term><literal>www.</literal></term>
2121 matches any domain that <emphasis>STARTS</emphasis> with
2122 <literal>www.</literal> (It also matches the domain
2123 <literal>www</literal> but most of the time that doesn't matter.)
2128 <term><literal>.example.</literal></term>
2131 matches any domain that <emphasis>CONTAINS</emphasis> <literal>.example.</literal>.
2132 And, by the way, also included would be any files or documents that exist
2133 within that domain since no path limitations are specified. (Correctly
2134 speaking: It matches any FQDN that contains <literal>example</literal> as
2135 a domain.) This might be <literal>www.example.com</literal>,
2136 <literal>news.example.de</literal>, or
2137 <literal>www.example.net/cgi/testing.pl</literal> for instance. All these
2145 Additionally, there are wild-cards that you can use in the domain names
2146 themselves. These work similarly to shell globbing type wild-cards:
2147 <quote>*</quote> represents zero or more arbitrary characters (this is
2149 <ulink url="http://en.wikipedia.org/wiki/Regular_expressions"><quote>Regular
2150 Expression</quote></ulink> based syntax of <quote>.*</quote>),
2151 <quote>?</quote> represents any single character (this is equivalent to the
2152 regular expression syntax of a simple <quote>.</quote>), and you can define
2153 <quote>character classes</quote> in square brackets which is similar to
2154 the same regular expression technique. All of this can be freely mixed:
2159 <term><literal>ad*.example.com</literal></term>
2162 matches <quote>adserver.example.com</quote>,
2163 <quote>ads.example.com</quote>, etc but not <quote>sfads.example.com</quote>
2168 <term><literal>*ad*.example.com</literal></term>
2171 matches all of the above, and then some.
2176 <term><literal>.?pix.com</literal></term>
2179 matches <literal>www.ipix.com</literal>,
2180 <literal>pictures.epix.com</literal>, <literal>a.b.c.d.e.upix.com</literal> etc.
2185 <term><literal>www[1-9a-ez].example.c*</literal></term>
2188 matches <literal>www1.example.com</literal>,
2189 <literal>www4.example.cc</literal>, <literal>wwwd.example.cy</literal>,
2190 <literal>wwwz.example.com</literal> etc., but <emphasis>not</emphasis>
2191 <literal>wwww.example.com</literal>.
2198 While flexible, this is not the sophistication of full regular expression based syntax.
2203 <!-- ~ End section ~ -->
2206 <!-- ~~~~~ New section ~~~~~ -->
2207 <sect3><title>The Path Pattern</title>
2210 <application>Privoxy</application> uses <quote>modern</quote> POSIX 1003.2
2211 <ulink url="http://en.wikipedia.org/wiki/Regular_expressions"><quote>Regular
2212 Expressions</quote></ulink> for matching the path portion (after the slash),
2213 and is thus more flexible.
2217 There is an <link linkend="regex">Appendix</link> with a brief quick-start into regular
2218 expressions, you also might want to have a look at your operating system's documentation
2219 on regular expressions (try <literal>man re_format</literal>).
2223 Note that the path pattern is automatically left-anchored at the <quote>/</quote>,
2224 i.e. it matches as if it would start with a <quote>^</quote> (regular expression speak
2225 for the beginning of a line).
2229 Please also note that matching in the path is <emphasis>CASE INSENSITIVE</emphasis>
2230 by default, but you can switch to case sensitive at any point in the pattern by using the
2231 <quote>(?-i)</quote> switch: <literal>www.example.com/(?-i)PaTtErN.*</literal> will match
2232 only documents whose path starts with <literal>PaTtErN</literal> in
2233 <emphasis>exactly</emphasis> this capitalization.
2238 <term><literal>.example.com/.*</literal></term>
2241 Is equivalent to just <quote>.example.com</quote>, since any documents
2242 within that domain are matched with or without the <quote>.*</quote>
2243 regular expression. This is redundant
2248 <term><literal>.example.com/.*/index.html$</literal></term>
2251 Will match any page in the domain of <quote>example.com</quote> that is
2252 named <quote>index.html</quote>, and that is part of some path. For
2253 example, it matches <quote>www.example.com/testing/index.html</quote> but
2254 NOT <quote>www.example.com/index.html</quote> because the regular
2255 expression called for at least two <quote>/'s</quote>, thus the path
2256 requirement. It also would match
2257 <quote>www.example.com/testing/index_html</quote>, because of the
2258 special meta-character <quote>.</quote>.
2263 <term><literal>.example.com/(.*/)?index\.html$</literal></term>
2266 This regular expression is conditional so it will match any page
2267 named <quote>index.html</quote> regardless of path which in this case can
2268 have one or more <quote>/'s</quote>. And this one must contain exactly
2269 <quote>.html</quote> (but does not have to end with that!).
2274 <term><literal>.example.com/(.*/)(ads|banners?|junk)</literal></term>
2277 This regular expression will match any path of <quote>example.com</quote>
2278 that contains any of the words <quote>ads</quote>, <quote>banner</quote>,
2279 <quote>banners</quote> (because of the <quote>?</quote>) or <quote>junk</quote>.
2280 The path does not have to end in these words, just contain them.
2285 <term><literal>.example.com/(.*/)(ads|banners?|junk)/.*\.(jpe?g|gif|png)$</literal></term>
2288 This is very much the same as above, except now it must end in either
2289 <quote>.jpg</quote>, <quote>.jpeg</quote>, <quote>.gif</quote> or <quote>.png</quote>. So this
2290 one is limited to common image formats.
2297 There are many, many good examples to be found in <filename>default.action</filename>,
2298 and more tutorials below in <link linkend="regex">Appendix on regular expressions</link>.
2303 <!-- ~ End section ~ -->
2306 <!-- ~~~~~ New section ~~~~~ -->
2307 <sect3 id="tag-pattern"><title>The Tag Pattern</title>
2310 Tag patterns are used to change the applying actions based on the
2311 request's tags. Tags can be created with either the
2312 <link linkend="CLIENT-HEADER-TAGGER">client-header-tagger</link>
2313 or the <link linkend="SERVER-HEADER-TAGGER">server-header-tagger</link> action.
2317 Tag patterns have to start with <quote>TAG:</quote>, so &my-app;
2318 can tell them apart from URL patterns. Everything after the colon
2319 including white space, is interpreted as a regular expression with
2320 path pattern syntax, except that tag patterns aren't left-anchored
2321 automatically (&my-app; doesn't silently add a <quote>^</quote>,
2322 you have to do it yourself if you need it).
2326 To match all requests that are tagged with <quote>foo</quote>
2327 your pattern line should be <quote>TAG:^foo$</quote>,
2328 <quote>TAG:foo</quote> would work as well, but it would also
2329 match requests whose tags contain <quote>foo</quote> somewhere.
2330 <quote>TAG: foo</quote> wouldn't work as it requires white space.
2334 Sections can contain URL and tag patterns at the same time,
2335 but tag patterns are checked after the URL patterns and thus
2336 always overrule them, even if they are located before the URL patterns.
2340 Once a new tag is added, Privoxy checks right away if it's matched by one
2341 of the tag patterns and updates the action settings accordingly. As a result
2342 tags can be used to activate other tagger actions, as long as these other
2343 taggers look for headers that haven't already be parsed.
2347 For example you could tag client requests which use the
2348 <literal>POST</literal> method,
2349 then use this tag to activate another tagger that adds a tag if cookies
2350 are sent, and then use a block action based on the cookie tag. This allows
2351 the outcome of one action, to be input into a subsequent action. However if
2352 you'd reverse the position of the described taggers, and activated the
2353 method tagger based on the cookie tagger, no method tags would be created.
2354 The method tagger would look for the request line, but at the time
2355 the cookie tag is created, the request line has already been parsed.
2359 While this is a limitation you should be aware of, this kind of
2360 indirection is seldom needed anyway and even the example doesn't
2361 make too much sense.
2366 <!-- ~~~~~ New section ~~~~~ -->
2367 <sect3 id="negative-tag-patterns"><title>The Negative Tag Patterns</title>
2370 To match requests that do not have a certain tag, specify a negative tag pattern
2371 by prefixing the tag pattern line with either <quote>NO-REQUEST-TAG:</quote>
2372 or <quote>NO-RESPONSE-TAG:</quote> instead of <quote>TAG:</quote>.
2376 Negative tag patterns created with <quote>NO-REQUEST-TAG:</quote> are checked
2377 after all client headers are scanned, the ones created with <quote>NO-RESPONSE-TAG:</quote>
2378 are checked after all server headers are scanned. In both cases all the created
2379 tags are considered.
2385 <!-- ~ End section ~ -->
2388 <!-- ~~~~~ New section ~~~~~ -->
2390 <sect2 id="actions">
2391 <title>Actions</title>
2393 All actions are disabled by default, until they are explicitly enabled
2394 somewhere in an actions file. Actions are turned on if preceded with a
2395 <quote>+</quote>, and turned off if preceded with a <quote>-</quote>. So a
2396 <literal>+action</literal> means <quote>do that action</quote>, e.g.
2397 <literal>+block</literal> means <quote>please block URLs that match the
2398 following patterns</quote>, and <literal>-block</literal> means <quote>don't
2399 block URLs that match the following patterns, even if <literal>+block</literal>
2400 previously applied.</quote>
2405 Again, actions are invoked by placing them on a line, enclosed in curly braces and
2406 separated by whitespace, like in
2407 <literal>{+some-action -some-other-action{some-parameter}}</literal>,
2408 followed by a list of URL patterns, one per line, to which they apply.
2409 Together, the actions line and the following pattern lines make up a section
2410 of the actions file.
2414 Actions fall into three categories:
2421 Boolean, i.e the action can only be <quote>enabled</quote> or
2422 <quote>disabled</quote>. Syntax:
2426 +<replaceable class="function">name</replaceable> # enable action <replaceable class="parameter">name</replaceable>
2427 -<replaceable class="function">name</replaceable> # disable action <replaceable class="parameter">name</replaceable></screen>
2430 Example: <literal>+handle-as-image</literal>
2437 Parameterized, where some value is required in order to enable this type of action.
2442 +<replaceable class="function">name</replaceable>{<replaceable class="parameter">param</replaceable>} # enable action and set parameter to <replaceable class="parameter">param</replaceable>,
2443 # overwriting parameter from previous match if necessary
2444 -<replaceable class="function">name</replaceable> # disable action. The parameter can be omitted</screen>
2447 Note that if the URL matches multiple positive forms of a parameterized action,
2448 the last match wins, i.e. the params from earlier matches are simply ignored.
2451 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>
2457 Multi-value. These look exactly like parameterized actions,
2458 but they behave differently: If the action applies multiple times to the
2459 same URL, but with different parameters, <emphasis>all</emphasis> the parameters
2460 from <emphasis>all</emphasis> matches are remembered. This is used for actions
2461 that can be executed for the same request repeatedly, like adding multiple
2462 headers, or filtering through multiple filters. Syntax:
2466 +<replaceable class="function">name</replaceable>{<replaceable class="parameter">param</replaceable>} # enable action and add <replaceable class="parameter">param</replaceable> to the list of parameters
2467 -<replaceable class="function">name</replaceable>{<replaceable class="parameter">param</replaceable>} # remove the parameter <replaceable class="parameter">param</replaceable> from the list of parameters
2468 # If it was the last one left, disable the action.
2469 <replaceable class="parameter">-name</replaceable> # disable this action completely and remove all parameters from the list</screen>
2472 Examples: <literal>+add-header{X-Fun-Header: Some text}</literal> and
2473 <literal>+filter{html-annoyances}</literal>
2481 If nothing is specified in any actions file, no <quote>actions</quote> are
2482 taken. So in this case <application>Privoxy</application> would just be a
2483 normal, non-blocking, non-filtering proxy. You must specifically enable the
2484 privacy and blocking features you need (although the provided default actions
2485 files will give a good starting point).
2489 Later defined action sections always over-ride earlier ones of the same type.
2490 So exceptions to any rules you make, should come in the latter part of the file (or
2491 in a file that is processed later when using multiple actions files such
2492 as <filename>user.action</filename>). For multi-valued actions, the actions
2493 are applied in the order they are specified. Actions files are processed in
2494 the order they are defined in <filename>config</filename> (the default
2495 installation has three actions files). It also quite possible for any given
2496 URL to match more than one <quote>pattern</quote> (because of wildcards and
2497 regular expressions), and thus to trigger more than one set of actions! Last
2501 <!-- start actions listing -->
2503 The list of valid <application>Privoxy</application> actions are:
2507 <!-- ********************************************************** -->
2508 <!-- Please note the below defined actions use id's that are -->
2509 <!-- probably linked from other places, so please don't change. -->
2511 <!-- ********************************************************** -->
2514 <!-- ~~~~~ New section ~~~~~ -->
2516 <sect3 renderas="sect4" id="add-header">
2517 <title>add-header</title>
2521 <term>Typical use:</term>
2523 <para>Confuse log analysis, custom applications</para>
2528 <term>Effect:</term>
2531 Sends a user defined HTTP header to the web server.
2538 <!-- boolean, parameterized, Multi-value -->
2540 <para>Multi-value.</para>
2545 <term>Parameter:</term>
2548 Any string value is possible. Validity of the defined HTTP headers is not checked.
2549 It is recommended that you use the <quote><literal>X-</literal></quote> prefix
2559 This action may be specified multiple times, in order to define multiple
2560 headers. This is rarely needed for the typical user. If you don't know what
2561 <quote>HTTP headers</quote> are, you definitely don't need to worry about this
2565 Headers added by this action are not modified by other actions.
2571 <term>Example usage:</term>
2574 <screen>+add-header{X-User-Tracking: sucks}</screen>
2582 <!-- ~~~~~ New section ~~~~~ -->
2583 <sect3 renderas="sect4" id="block">
2584 <title>block</title>
2588 <term>Typical use:</term>
2590 <para>Block ads or other unwanted content</para>
2595 <term>Effect:</term>
2598 Requests for URLs to which this action applies are blocked, i.e. the
2599 requests are trapped by &my-app; and the requested URL is never retrieved,
2600 but is answered locally with a substitute page or image, as determined by
2602 linkend="handle-as-image">handle-as-image</link></literal>,
2604 linkend="set-image-blocker">set-image-blocker</link></literal>, and
2606 linkend="handle-as-empty-document">handle-as-empty-document</link></literal> actions.
2614 <!-- boolean, parameterized, Multi-value -->
2616 <para>Parameterized.</para>
2621 <term>Parameter:</term>
2623 <para>A block reason that should be given to the user.</para>
2631 <application>Privoxy</application> sends a special <quote>BLOCKED</quote> page
2632 for requests to blocked pages. This page contains the block reason given as
2633 parameter, a link to find out why the block action applies, and a click-through
2634 to the blocked content (the latter only if the force feature is available and
2638 A very important exception occurs if <emphasis>both</emphasis>
2639 <literal>block</literal> and <literal><link linkend="handle-as-image">handle-as-image</link></literal>,
2640 apply to the same request: it will then be replaced by an image. If
2641 <literal><link linkend="set-image-blocker">set-image-blocker</link></literal>
2642 (see below) also applies, the type of image will be determined by its parameter,
2643 if not, the standard checkerboard pattern is sent.
2646 It is important to understand this process, in order
2647 to understand how <application>Privoxy</application> deals with
2648 ads and other unwanted content. Blocking is a core feature, and one
2649 upon which various other features depend.
2652 The <literal><link linkend="filter">filter</link></literal>
2653 action can perform a very similar task, by <quote>blocking</quote>
2654 banner images and other content through rewriting the relevant URLs in the
2655 document's HTML source, so they don't get requested in the first place.
2656 Note that this is a totally different technique, and it's easy to confuse the two.
2662 <term>Example usage (section):</term>
2665 <screen>{+block{No nasty stuff for you.}}
2666 # Block and replace with "blocked" page
2667 .nasty-stuff.example.com
2669 {+block{Doubleclick banners.} +handle-as-image}
2670 # Block and replace with image
2674 {+block{Layered ads.} +handle-as-empty-document}
2675 # Block and then ignore
2676 adserver.example.net/.*\.js$</screen>
2686 <!-- ~~~~~ New section ~~~~~ -->
2687 <sect3 renderas="sect4" id="change-x-forwarded-for">
2688 <title>change-x-forwarded-for</title>
2692 <term>Typical use:</term>
2694 <para>Improve privacy by not forwarding the source of the request in the HTTP headers.</para>
2699 <term>Effect:</term>
2702 Deletes the <quote>X-Forwarded-For:</quote> HTTP header from the client request,
2710 <!-- Boolean, Parameterized, Multi-value -->
2712 <para>Parameterized.</para>
2717 <term>Parameter:</term>
2721 <para><quote>block</quote> to delete the header.</para>
2725 <quote>add</quote> to create the header (or append
2726 the client's IP address to an already existing one).
2737 It is safe and recommended to use <literal>block</literal>.
2740 Forwarding the source address of the request may make
2741 sense in some multi-user setups but is also a privacy risk.
2746 <term>Example usage:</term>
2749 <screen>+change-x-forwarded-for{block}</screen>
2756 <!-- ~~~~~ New section ~~~~~ -->
2757 <sect3 renderas="sect4" id="client-header-filter">
2758 <title>client-header-filter</title>
2762 <term>Typical use:</term>
2765 Rewrite or remove single client headers.
2771 <term>Effect:</term>
2774 All client headers to which this action applies are filtered on-the-fly through
2775 the specified regular expression based substitutions.
2782 <!-- boolean, parameterized, Multi-value -->
2784 <para>Parameterized.</para>
2789 <term>Parameter:</term>
2792 The name of a client-header filter, as defined in one of the
2793 <link linkend="filter-file">filter files</link>.
2802 Client-header filters are applied to each header on its own, not to
2803 all at once. This makes it easier to diagnose problems, but on the downside
2804 you can't write filters that only change header x if header y's value is z.
2805 You can do that by using tags though.
2808 Client-header filters are executed after the other header actions have finished
2809 and use their output as input.
2812 If the request URI gets changed, &my-app; will detect that and use the new
2813 one. This can be used to rewrite the request destination behind the client's
2814 back, for example to specify a Tor exit relay for certain requests.
2817 Please refer to the <link linkend="filter-file">filter file chapter</link>
2818 to learn which client-header filters are available by default, and how to
2826 <term>Example usage (section):</term>
2830 # Hide Tor exit notation in Host and Referer Headers
2831 {+client-header-filter{hide-tor-exit-notation}}
2842 <!-- ~~~~~ New section ~~~~~ -->
2843 <sect3 renderas="sect4" id="client-header-tagger">
2844 <title>client-header-tagger</title>
2848 <term>Typical use:</term>
2851 Block requests based on their headers.
2857 <term>Effect:</term>
2860 Client headers to which this action applies are filtered on-the-fly through
2861 the specified regular expression based substitutions, the result is used as
2869 <!-- boolean, parameterized, Multi-value -->
2871 <para>Parameterized.</para>
2876 <term>Parameter:</term>
2879 The name of a client-header tagger, as defined in one of the
2880 <link linkend="filter-file">filter files</link>.
2889 Client-header taggers are applied to each header on its own,
2890 and as the header isn't modified, each tagger <quote>sees</quote>
2894 Client-header taggers are the first actions that are executed
2895 and their tags can be used to control every other action.
2901 <term>Example usage (section):</term>
2905 # Tag every request with the User-Agent header
2906 {+client-header-tagger{user-agent}}
2909 # Tagging itself doesn't change the action
2910 # settings, sections with TAG patterns do:
2912 # If it's a download agent, use a different forwarding proxy,
2913 # show the real User-Agent and make sure resume works.
2914 {+forward-override{forward-socks5 10.0.0.2:2222 .} \
2915 -hide-if-modified-since \
2916 -overwrite-last-modified \
2921 TAG:^User-Agent: NetBSD-ftp/
2922 TAG:^User-Agent: Novell ZYPP Installer
2923 TAG:^User-Agent: RPM APT-HTTP/
2924 TAG:^User-Agent: fetch libfetch/
2925 TAG:^User-Agent: Ubuntu APT-HTTP/
2926 TAG:^User-Agent: MPlayer/
2931 # Tag all requests with the Range header set
2932 {+client-header-tagger{range-requests}}
2935 # Disable filtering for the tagged requests.
2937 # With filtering enabled Privoxy would remove the Range headers
2938 # to be able to filter the whole response. The downside is that
2939 # it prevents clients from resuming downloads or skipping over
2940 # parts of multimedia files.
2941 {-filter -deanimate-gifs}
2952 <!-- ~~~~~ New section ~~~~~ -->
2953 <sect3 renderas="sect4" id="content-type-overwrite">
2954 <title>content-type-overwrite</title>
2958 <term>Typical use:</term>
2960 <para>Stop useless download menus from popping up, or change the browser's rendering mode</para>
2965 <term>Effect:</term>
2968 Replaces the <quote>Content-Type:</quote> HTTP server header.
2975 <!-- Boolean, Parameterized, Multi-value -->
2977 <para>Parameterized.</para>
2982 <term>Parameter:</term>
2994 The <quote>Content-Type:</quote> HTTP server header is used by the
2995 browser to decide what to do with the document. The value of this
2996 header can cause the browser to open a download menu instead of
2997 displaying the document by itself, even if the document's format is
2998 supported by the browser.
3001 The declared content type can also affect which rendering mode
3002 the browser chooses. If XHTML is delivered as <quote>text/html</quote>,
3003 many browsers treat it as yet another broken HTML document.
3004 If it is send as <quote>application/xml</quote>, browsers with
3005 XHTML support will only display it, if the syntax is correct.
3008 If you see a web site that proudly uses XHTML buttons, but sets
3009 <quote>Content-Type: text/html</quote>, you can use &my-app;
3010 to overwrite it with <quote>application/xml</quote> and validate
3011 the web master's claim inside your XHTML-supporting browser.
3012 If the syntax is incorrect, the browser will complain loudly.
3015 You can also go the opposite direction: if your browser prints
3016 error messages instead of rendering a document falsely declared
3017 as XHTML, you can overwrite the content type with
3018 <quote>text/html</quote> and have it rendered as broken HTML document.
3021 By default <literal>content-type-overwrite</literal> only replaces
3022 <quote>Content-Type:</quote> headers that look like some kind of text.
3023 If you want to overwrite it unconditionally, you have to combine it with
3024 <literal><link linkend="force-text-mode">force-text-mode</link></literal>.
3025 This limitation exists for a reason, think twice before circumventing it.
3028 Most of the time it's easier to replace this action with a custom
3029 <literal><link linkend="server-header-filter">server-header filter</link></literal>.
3030 It allows you to activate it for every document of a certain site and it will still
3031 only replace the content types you aimed at.
3034 Of course you can apply <literal>content-type-overwrite</literal>
3035 to a whole site and then make URL based exceptions, but it's a lot
3036 more work to get the same precision.
3042 <term>Example usage (sections):</term>
3045 <screen># Check if www.example.net/ really uses valid XHTML
3046 { +content-type-overwrite{application/xml} }
3049 # but leave the content type unmodified if the URL looks like a style sheet
3050 {-content-type-overwrite}
3051 www.example.net/.*\.css$
3052 www.example.net/.*style
3061 <!-- ~~~~~ New section ~~~~~ -->
3062 <sect3 renderas="sect4" id="crunch-client-header">
3066 <title>crunch-client-header</title>
3070 <term>Typical use:</term>
3072 <para>Remove a client header <application>Privoxy</application> has no dedicated action for.</para>
3077 <term>Effect:</term>
3080 Deletes every header sent by the client that contains the string the user supplied as parameter.
3087 <!-- Boolean, Parameterized, Multi-value -->
3089 <para>Parameterized.</para>
3094 <term>Parameter:</term>
3106 This action allows you to block client headers for which no dedicated
3107 <application>Privoxy</application> action exists.
3108 <application>Privoxy</application> will remove every client header that
3109 contains the string you supplied as parameter.
3112 Regular expressions are <emphasis>not supported</emphasis> and you can't
3113 use this action to block different headers in the same request, unless
3114 they contain the same string.
3117 <literal>crunch-client-header</literal> is only meant for quick tests.
3118 If you have to block several different headers, or only want to modify
3119 parts of them, you should use a
3120 <literal><link linkend="client-header-filter">client-header filter</link></literal>.
3124 Don't block any header without understanding the consequences.
3131 <term>Example usage (section):</term>
3134 <screen># Block the non-existent "Privacy-Violation:" client header
3135 { +crunch-client-header{Privacy-Violation:} }
3145 <!-- ~~~~~ New section ~~~~~ -->
3146 <sect3 renderas="sect4" id="crunch-if-none-match">
3147 <title>crunch-if-none-match</title>
3153 <term>Typical use:</term>
3155 <para>Prevent yet another way to track the user's steps between sessions.</para>
3160 <term>Effect:</term>
3163 Deletes the <quote>If-None-Match:</quote> HTTP client header.
3170 <!-- Boolean, Parameterized, Multi-value -->
3172 <para>Boolean.</para>
3177 <term>Parameter:</term>
3189 Removing the <quote>If-None-Match:</quote> HTTP client header
3190 is useful for filter testing, where you want to force a real
3191 reload instead of getting status code <quote>304</quote> which
3192 would cause the browser to use a cached copy of the page.
3195 It is also useful to make sure the header isn't used as a cookie
3196 replacement (unlikely but possible).
3199 Blocking the <quote>If-None-Match:</quote> header shouldn't cause any
3200 caching problems, as long as the <quote>If-Modified-Since:</quote> header
3201 isn't blocked or missing as well.
3204 It is recommended to use this action together with
3205 <literal><link linkend="hide-if-modified-since">hide-if-modified-since</link></literal>
3207 <literal><link linkend="overwrite-last-modified">overwrite-last-modified</link></literal>.
3213 <term>Example usage (section):</term>
3216 <screen># Let the browser revalidate cached documents but don't
3217 # allow the server to use the revalidation headers for user tracking.
3218 {+hide-if-modified-since{-60} \
3219 +overwrite-last-modified{randomize} \
3220 +crunch-if-none-match}
3229 <!-- ~~~~~ New section ~~~~~ -->
3230 <sect3 renderas="sect4" id="crunch-incoming-cookies">
3231 <title>crunch-incoming-cookies</title>
3235 <term>Typical use:</term>
3238 Prevent the web server from setting HTTP cookies on your system
3244 <term>Effect:</term>
3247 Deletes any <quote>Set-Cookie:</quote> HTTP headers from server replies.
3254 <!-- Boolean, Parameterized, Multi-value -->
3256 <para>Boolean.</para>
3261 <term>Parameter:</term>
3273 This action is only concerned with <emphasis>incoming</emphasis> HTTP cookies. For
3274 <emphasis>outgoing</emphasis> HTTP cookies, use
3275 <literal><link linkend="crunch-outgoing-cookies">crunch-outgoing-cookies</link></literal>.
3276 Use <emphasis>both</emphasis> to disable HTTP cookies completely.
3279 It makes <emphasis>no sense at all</emphasis> to use this action in conjunction
3280 with the <literal><link linkend="session-cookies-only">session-cookies-only</link></literal> action,
3281 since it would prevent the session cookies from being set. See also
3282 <literal><link linkend="filter-content-cookies">filter-content-cookies</link></literal>.
3288 <term>Example usage:</term>
3291 <screen>+crunch-incoming-cookies</screen>
3299 <!-- ~~~~~ New section ~~~~~ -->
3300 <sect3 renderas="sect4" id="crunch-server-header">
3301 <title>crunch-server-header</title>
3307 <term>Typical use:</term>
3309 <para>Remove a server header <application>Privoxy</application> has no dedicated action for.</para>
3314 <term>Effect:</term>
3317 Deletes every header sent by the server that contains the string the user supplied as parameter.
3324 <!-- Boolean, Parameterized, Multi-value -->
3326 <para>Parameterized.</para>
3331 <term>Parameter:</term>
3343 This action allows you to block server headers for which no dedicated
3344 <application>Privoxy</application> action exists. <application>Privoxy</application>
3345 will remove every server header that contains the string you supplied as parameter.
3348 Regular expressions are <emphasis>not supported</emphasis> and you can't
3349 use this action to block different headers in the same request, unless
3350 they contain the same string.
3353 <literal>crunch-server-header</literal> is only meant for quick tests.
3354 If you have to block several different headers, or only want to modify
3355 parts of them, you should use a custom
3356 <literal><link linkend="server-header-filter">server-header filter</link></literal>.
3360 Don't block any header without understanding the consequences.
3367 <term>Example usage (section):</term>
3370 <screen># Crunch server headers that try to prevent caching
3371 { +crunch-server-header{no-cache} }
3380 <!-- ~~~~~ New section ~~~~~ -->
3381 <sect3 renderas="sect4" id="crunch-outgoing-cookies">
3382 <title>crunch-outgoing-cookies</title>
3386 <term>Typical use:</term>
3389 Prevent the web server from reading any HTTP cookies from your system
3395 <term>Effect:</term>
3398 Deletes any <quote>Cookie:</quote> HTTP headers from client requests.
3405 <!-- Boolean, Parameterized, Multi-value -->
3407 <para>Boolean.</para>
3412 <term>Parameter:</term>
3424 This action is only concerned with <emphasis>outgoing</emphasis> HTTP cookies. For
3425 <emphasis>incoming</emphasis> HTTP cookies, use
3426 <literal><link linkend="crunch-incoming-cookies">crunch-incoming-cookies</link></literal>.
3427 Use <emphasis>both</emphasis> to disable HTTP cookies completely.
3430 It makes <emphasis>no sense at all</emphasis> to use this action in conjunction
3431 with the <literal><link linkend="session-cookies-only">session-cookies-only</link></literal> action,
3432 since it would prevent the session cookies from being read.
3438 <term>Example usage:</term>
3441 <screen>+crunch-outgoing-cookies</screen>
3450 <!-- ~~~~~ New section ~~~~~ -->
3451 <sect3 renderas="sect4" id="deanimate-gifs">
3452 <title>deanimate-gifs</title>
3456 <term>Typical use:</term>
3458 <para>Stop those annoying, distracting animated GIF images.</para>
3463 <term>Effect:</term>
3466 De-animate GIF animations, i.e. reduce them to their first or last image.
3473 <!-- boolean, parameterized, Multi-value -->
3475 <para>Parameterized.</para>
3480 <term>Parameter:</term>
3483 <quote>last</quote> or <quote>first</quote>
3492 This will also shrink the images considerably (in bytes, not pixels!). If
3493 the option <quote>first</quote> is given, the first frame of the animation
3494 is used as the replacement. If <quote>last</quote> is given, the last
3495 frame of the animation is used instead, which probably makes more sense for
3496 most banner animations, but also has the risk of not showing the entire
3497 last frame (if it is only a delta to an earlier frame).
3500 You can safely use this action with patterns that will also match non-GIF
3501 objects, because no attempt will be made at anything that doesn't look like
3508 <term>Example usage:</term>
3511 <screen>+deanimate-gifs{last}</screen>
3518 <!-- ~~~~~ New section ~~~~~ -->
3519 <sect3 renderas="sect4" id="downgrade-http-version">
3520 <title>downgrade-http-version</title>
3524 <term>Typical use:</term>
3526 <para>Work around (very rare) problems with HTTP/1.1</para>
3531 <term>Effect:</term>
3534 Downgrades HTTP/1.1 client requests and server replies to HTTP/1.0.
3541 <!-- boolean, parameterized, Multi-value -->
3543 <para>Boolean.</para>
3548 <term>Parameter:</term>
3560 This is a left-over from the time when <application>Privoxy</application>
3561 didn't support important HTTP/1.1 features well. It is left here for the
3562 unlikely case that you experience HTTP/1.1-related problems with some server
3566 Note that enabling this action is only a workaround. It should not
3567 be enabled for sites that work without it. While it shouldn't break
3568 any pages, it has an (usually negative) performance impact.
3571 If you come across a site where enabling this action helps, please report it,
3572 so the cause of the problem can be analyzed. If the problem turns out to be
3573 caused by a bug in <application>Privoxy</application> it should be
3574 fixed so the following release works without the work around.
3580 <term>Example usage (section):</term>
3583 <screen>{+downgrade-http-version}
3584 problem-host.example.com</screen>
3592 <!-- ~~~~~ New section ~~~~~ -->
3593 <sect3 renderas="sect4" id="fast-redirects">
3594 <title>fast-redirects</title>
3598 <term>Typical use:</term>
3600 <para>Fool some click-tracking scripts and speed up indirect links.</para>
3605 <term>Effect:</term>
3608 Detects redirection URLs and redirects the browser without contacting
3609 the redirection server first.
3616 <!-- boolean, parameterized, Multi-value -->
3618 <para>Parameterized.</para>
3623 <term>Parameter:</term>
3628 <quote>simple-check</quote> to just search for the string <quote>http://</quote>
3629 to detect redirection URLs.
3634 <quote>check-decoded-url</quote> to decode URLs (if necessary) before searching
3635 for redirection URLs.
3646 Many sites, like yahoo.com, don't just link to other sites. Instead, they
3647 will link to some script on their own servers, giving the destination as a
3648 parameter, which will then redirect you to the final target. URLs
3649 resulting from this scheme typically look like:
3650 <quote>http://www.example.org/click-tracker.cgi?target=http%3a//www.example.net/</quote>.
3653 Sometimes, there are even multiple consecutive redirects encoded in the
3654 URL. These redirections via scripts make your web browsing more traceable,
3655 since the server from which you follow such a link can see where you go
3656 to. Apart from that, valuable bandwidth and time is wasted, while your
3657 browser asks the server for one redirect after the other. Plus, it feeds
3661 This feature is currently not very smart and is scheduled for improvement.
3662 If it is enabled by default, you will have to create some exceptions to
3663 this action. It can lead to failures in several ways:
3666 Not every URLs with other URLs as parameters is evil.
3667 Some sites offer a real service that requires this information to work.
3668 For example a validation service needs to know, which document to validate.
3669 <literal>fast-redirects</literal> assumes that every URL parameter that
3670 looks like another URL is a redirection target, and will always redirect to
3671 the last one. Most of the time the assumption is correct, but if it isn't,
3672 the user gets redirected anyway.
3675 Another failure occurs if the URL contains other parameters after the URL parameter.
3677 <quote>http://www.example.org/?redirect=http%3a//www.example.net/&foo=bar</quote>.
3678 contains the redirection URL <quote>http://www.example.net/</quote>,
3679 followed by another parameter. <literal>fast-redirects</literal> doesn't know that
3680 and will cause a redirect to <quote>http://www.example.net/&foo=bar</quote>.
3681 Depending on the target server configuration, the parameter will be silently ignored
3682 or lead to a <quote>page not found</quote> error. You can prevent this problem by
3683 first using the <literal><link linkend="redirect">redirect</link></literal> action
3684 to remove the last part of the URL, but it requires a little effort.
3687 To detect a redirection URL, <literal>fast-redirects</literal> only
3688 looks for the string <quote>http://</quote>, either in plain text
3689 (invalid but often used) or encoded as <quote>http%3a//</quote>.
3690 Some sites use their own URL encoding scheme, encrypt the address
3691 of the target server or replace it with a database id. In theses cases
3692 <literal>fast-redirects</literal> is fooled and the request reaches the
3693 redirection server where it probably gets logged.
3699 <term>Example usage:</term>
3703 { +fast-redirects{simple-check} }
3706 { +fast-redirects{check-decoded-url} }
3707 another.example.com/testing</screen>
3716 <!-- ~~~~~ New section ~~~~~ -->
3717 <sect3 renderas="sect4" id="filter">
3718 <title>filter</title>
3722 <term>Typical use:</term>
3724 <para>Get rid of HTML and JavaScript annoyances, banner advertisements (by size),
3725 do fun text replacements, add personalized effects, etc.</para>
3730 <term>Effect:</term>
3733 All instances of text-based type, most notably HTML and JavaScript, to which
3734 this action applies, can be filtered on-the-fly through the specified regular
3735 expression based substitutions. (Note: as of version 3.0.3 plain text documents
3736 are exempted from filtering, because web servers often use the
3737 <literal>text/plain</literal> MIME type for all files whose type they don't know.)
3744 <!-- boolean, parameterized, Multi-value -->
3746 <para>Parameterized.</para>
3751 <term>Parameter:</term>
3754 The name of a content filter, as defined in the <link linkend="filter-file">filter file</link>.
3755 Filters can be defined in one or more files as defined by the
3756 <literal><link linkend="filterfile">filterfile</link></literal>
3757 option in the <link linkend="config">config file</link>.
3758 <filename>default.filter</filename> is the collection of filters
3759 supplied by the developers. Locally defined filters should go
3760 in their own file, such as <filename>user.filter</filename>.
3763 When used in its negative form,
3764 and without parameters, <emphasis>all</emphasis> filtering is completely disabled.
3773 For your convenience, there are a number of pre-defined filters available
3774 in the distribution filter file that you can use. See the examples below for
3778 Filtering requires buffering the page content, which may appear to
3779 slow down page rendering since nothing is displayed until all content has
3780 passed the filters. (The total time until the page is completely rendered
3781 doesn't change much, but it may be perceived as slower since the page is
3782 not incrementally displayed.)
3783 This effect will be more noticeable on slower connections.
3786 <quote>Rolling your own</quote>
3787 filters requires a knowledge of
3788 <ulink url="http://en.wikipedia.org/wiki/Regular_expressions"><quote>Regular
3789 Expressions</quote></ulink> and
3790 <ulink url="http://en.wikipedia.org/wiki/Html"><quote>HTML</quote></ulink>.
3791 This is very powerful feature, and potentially very intrusive.
3792 Filters should be used with caution, and where an equivalent
3793 <quote>action</quote> is not available.
3796 The amount of data that can be filtered is limited to the
3797 <literal><link linkend="buffer-limit">buffer-limit</link></literal>
3798 option in the main <link linkend="config">config file</link>. The
3799 default is 4096 KB (4 Megs). Once this limit is exceeded, the buffered
3800 data, and all pending data, is passed through unfiltered.
3803 Inappropriate MIME types, such as zipped files, are not filtered at all.
3804 (Again, only text-based types except plain text). Encrypted SSL data
3805 (from HTTPS servers) cannot be filtered either, since this would violate
3806 the integrity of the secure transaction. In some situations it might
3807 be necessary to protect certain text, like source code, from filtering
3808 by defining appropriate <literal>-filter</literal> exceptions.
3811 Compressed content can't be filtered either, but if &my-app;
3812 is compiled with zlib support and a supported compression algorithm
3813 is used (gzip or deflate), &my-app; can first decompress the content
3817 If you use a &my-app; version without zlib support, but want filtering to work on
3818 as much documents as possible, even those that would normally be sent compressed,
3819 you must use the <literal><link linkend="prevent-compression">prevent-compression</link></literal>
3820 action in conjunction with <literal>filter</literal>.
3823 Content filtering can achieve some of the same effects as the
3824 <literal><link linkend="block">block</link></literal>
3825 action, i.e. it can be used to block ads and banners. But the mechanism
3826 works quite differently. One effective use, is to block ad banners
3827 based on their size (see below), since many of these seem to be somewhat
3831 <link linkend="contact">Feedback</link> with suggestions for new or
3832 improved filters is particularly welcome!
3835 The below list has only the names and a one-line description of each
3836 predefined filter. There are <link linkend="predefined-filters">more
3837 verbose explanations</link> of what these filters do in the <link
3838 linkend="filter-file">filter file chapter</link>.
3844 <term>Example usage (with filters from the distribution <filename>default.filter</filename> file).
3845 See <link linkend="PREDEFINED-FILTERS">the Predefined Filters section</link> for
3846 more explanation on each:</term>
3849 <anchor id="filter-js-annoyances">
3850 <screen>+filter{js-annoyances} # Get rid of particularly annoying JavaScript abuse.</screen>
3853 <anchor id="filter-js-events">
3854 <screen>+filter{js-events} # Kill JavaScript event bindings and timers (Radically destructive! Only for extra nasty sites).</screen>
3857 <anchor id="filter-html-annoyances">
3858 <screen>+filter{html-annoyances} # Get rid of particularly annoying HTML abuse.</screen>
3861 <anchor id="filter-content-cookies">
3862 <screen>+filter{content-cookies} # Kill cookies that come in the HTML or JS content.</screen>
3865 <anchor id="filter-refresh-tags">
3866 <screen>+filter{refresh-tags} # Kill automatic refresh tags if refresh time is larger than 9 seconds.</screen>
3869 <anchor id="filter-unsolicited-popups">
3870 <screen>+filter{unsolicited-popups} # Disable only unsolicited pop-up windows.</screen>
3873 <anchor id="filter-all-popups">
3874 <screen>+filter{all-popups} # Kill all popups in JavaScript and HTML.</screen>
3877 <anchor id="filter-img-reorder">
3878 <screen>+filter{img-reorder} # Reorder attributes in <img> tags to make the banners-by-* filters more effective.</screen>
3881 <anchor id="filter-banners-by-size">
3882 <screen>+filter{banners-by-size} # Kill banners by size.</screen>
3885 <anchor id="filter-banners-by-link">
3886 <screen>+filter{banners-by-link} # Kill banners by their links to known clicktrackers.</screen>
3889 <anchor id="filter-webbugs">
3890 <screen>+filter{webbugs} # Squish WebBugs (1x1 invisible GIFs used for user tracking).</screen>
3893 <anchor id="filter-tiny-textforms">
3894 <screen>+filter{tiny-textforms} # Extend those tiny textareas up to 40x80 and kill the hard wrap.</screen>
3897 <anchor id="filter-jumping-windows">
3898 <screen>+filter{jumping-windows} # Prevent windows from resizing and moving themselves.</screen>
3901 <anchor id="filter-frameset-borders">
3902 <screen>+filter{frameset-borders} # Give frames a border and make them resizable.</screen>
3905 <anchor id="filter-iframes">
3906 <screen>+filter{iframes} # Removes all detected iframes. Should only be enabled for individual sites.</screen>
3909 <anchor id="filter-demoronizer">
3910 <screen>+filter{demoronizer} # Fix MS's non-standard use of standard charsets.</screen>
3913 <anchor id="filter-shockwave-flash">
3914 <screen>+filter{shockwave-flash} # Kill embedded Shockwave Flash objects.</screen>
3917 <anchor id="filter-quicktime-kioskmode">
3918 <screen>+filter{quicktime-kioskmode} # Make Quicktime movies saveable.</screen>
3921 <anchor id="filter-fun">
3922 <screen>+filter{fun} # Text replacements for subversive browsing fun!</screen>
3925 <anchor id="filter-crude-parental">
3926 <screen>+filter{crude-parental} # Crude parental filtering. Note that this filter doesn't work reliably.</screen>
3929 <anchor id="filter-ie-exploits">
3930 <screen>+filter{ie-exploits} # Disable some known Internet Explorer bug exploits.</screen>
3933 <anchor id="filter-site-specifics">
3934 <screen>+filter{site-specifics} # Cure for site-specific problems. Don't apply generally!</screen>
3937 <anchor id="filter-no-ping">
3938 <screen>+filter{no-ping} # Removes non-standard ping attributes in <a> and <area> tags.</screen>
3941 <anchor id="filter-google">
3942 <screen>+filter{google} # CSS-based block for Google text ads. Also removes a width limitation and the toolbar advertisement.</screen>
3945 <anchor id="filter-yahoo">
3946 <screen>+filter{yahoo} # CSS-based block for Yahoo text ads. Also removes a width limitation.</screen>
3949 <anchor id="filter-msn">
3950 <screen>+filter{msn} # CSS-based block for MSN text ads. Also removes tracking URLs and a width limitation.</screen>
3953 <anchor id="filter-blogspot">
3954 <screen>+filter{blogspot} # Cleans up some Blogspot blogs. Read the fine print before using this.</screen>
3962 <!-- ~~~~~ New section ~~~~~ -->
3963 <sect3 renderas="sect4" id="force-text-mode">
3964 <title>force-text-mode</title>
3970 <term>Typical use:</term>
3972 <para>Force <application>Privoxy</application> to treat a document as if it was in some kind of <emphasis>text</emphasis> format. </para>
3977 <term>Effect:</term>
3980 Declares a document as text, even if the <quote>Content-Type:</quote> isn't detected as such.
3987 <!-- Boolean, Parameterized, Multi-value -->
3989 <para>Boolean.</para>
3994 <term>Parameter:</term>
4006 As explained <literal><link linkend="filter">above</link></literal>,
4007 <application>Privoxy</application> tries to only filter files that are
4008 in some kind of text format. The same restrictions apply to
4009 <literal><link linkend="content-type-overwrite">content-type-overwrite</link></literal>.
4010 <literal>force-text-mode</literal> declares a document as text,
4011 without looking at the <quote>Content-Type:</quote> first.
4015 Think twice before activating this action. Filtering binary data
4016 with regular expressions can cause file damage.
4023 <term>Example usage:</term>
4036 <!-- ~~~~~ New section ~~~~~ -->
4037 <sect3 renderas="sect4" id="forward-override">
4038 <title>forward-override</title>
4044 <term>Typical use:</term>
4046 <para>Change the forwarding settings based on User-Agent or request origin</para>
4051 <term>Effect:</term>
4054 Overrules the forward directives in the configuration file.
4061 <!-- Boolean, Parameterized, Multi-value -->
4063 <para>Multi-value.</para>
4068 <term>Parameter:</term>
4072 <para><quote>forward .</quote> to use a direct connection without any additional proxies.</para>
4076 <quote>forward 127.0.0.1:8123</quote> to use the HTTP proxy listening at 127.0.0.1 port 8123.
4081 <quote>forward-socks4a 127.0.0.1:9050 .</quote> to use the socks4a proxy listening at
4082 127.0.0.1 port 9050. Replace <quote>forward-socks4a</quote> with <quote>forward-socks4</quote>
4083 to use a socks4 connection (with local DNS resolution) instead, use <quote>forward-socks5</quote>
4084 for socks5 connections (with remote DNS resolution).
4089 <quote>forward-socks4a 127.0.0.1:9050 proxy.example.org:8000</quote> to use the socks4a proxy
4090 listening at 127.0.0.1 port 9050 to reach the HTTP proxy listening at proxy.example.org port 8000.
4091 Replace <quote>forward-socks4a</quote> with <quote>forward-socks4</quote> to use a socks4 connection
4092 (with local DNS resolution) instead, use <quote>forward-socks5</quote>
4093 for socks5 connections (with remote DNS resolution).
4104 This action takes parameters similar to the
4105 <link linkend="forwarding">forward</link> directives in the configuration
4106 file, but without the URL pattern. It can be used as replacement, but normally it's only
4107 used in cases where matching based on the request URL isn't sufficient.
4111 Please read the description for the <link linkend="forwarding">forward</link> directives before
4112 using this action. Forwarding to the wrong people will reduce your privacy and increase the
4113 chances of man-in-the-middle attacks.
4116 If the ports are missing or invalid, default values will be used. This might change
4117 in the future and you shouldn't rely on it. Otherwise incorrect syntax causes Privoxy
4121 Use the <ulink url="http://config.privoxy.org/show-url-info">show-url-info CGI page</ulink>
4122 to verify that your forward settings do what you thought the do.
4129 <term>Example usage:</term>
4133 # Always use direct connections for requests previously tagged as
4134 # <quote>User-Agent: fetch libfetch/2.0</quote> and make sure
4135 # resuming downloads continues to work.
4136 # This way you can continue to use Tor for your normal browsing,
4137 # without overloading the Tor network with your FreeBSD ports updates
4138 # or downloads of bigger files like ISOs.
4139 # Note that HTTP headers are easy to fake and therefore their
4140 # values are as (un)trustworthy as your clients and users.
4141 {+forward-override{forward .} \
4142 -hide-if-modified-since \
4143 -overwrite-last-modified \
4145 TAG:^User-Agent: fetch libfetch/2\.0$
4154 <!-- ~~~~~ New section ~~~~~ -->
4155 <sect3 renderas="sect4" id="handle-as-empty-document">
4156 <title>handle-as-empty-document</title>
4162 <term>Typical use:</term>
4164 <para>Mark URLs that should be replaced by empty documents <emphasis>if they get blocked</emphasis></para>
4169 <term>Effect:</term>
4172 This action alone doesn't do anything noticeable. It just marks URLs.
4173 If the <literal><link linkend="block">block</link></literal> action <emphasis>also applies</emphasis>,
4174 the presence or absence of this mark decides whether an HTML <quote>BLOCKED</quote>
4175 page, or an empty document will be sent to the client as a substitute for the blocked content.
4176 The <emphasis>empty</emphasis> document isn't literally empty, but actually contains a single space.
4183 <!-- Boolean, Parameterized, Multi-value -->
4185 <para>Boolean.</para>
4190 <term>Parameter:</term>
4202 Some browsers complain about syntax errors if JavaScript documents
4203 are blocked with <application>Privoxy's</application>
4204 default HTML page; this option can be used to silence them.
4205 And of course this action can also be used to eliminate the &my-app;
4206 BLOCKED message in frames.
4209 The content type for the empty document can be specified with
4210 <literal><link linkend="content-type-overwrite">content-type-overwrite{}</link></literal>,
4211 but usually this isn't necessary.
4217 <term>Example usage:</term>
4220 <screen># Block all documents on example.org that end with ".js",
4221 # but send an empty document instead of the usual HTML message.
4222 {+block{Blocked JavaScript} +handle-as-empty-document}
4232 <!-- ~~~~~ New section ~~~~~ -->
4233 <sect3 renderas="sect4" id="handle-as-image">
4234 <title>handle-as-image</title>
4238 <term>Typical use:</term>
4240 <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>
4245 <term>Effect:</term>
4248 This action alone doesn't do anything noticeable. It just marks URLs as images.
4249 If the <literal><link linkend="block">block</link></literal> action <emphasis>also applies</emphasis>,
4250 the presence or absence of this mark decides whether an HTML <quote>blocked</quote>
4251 page, or a replacement image (as determined by the <literal><link
4252 linkend="set-image-blocker">set-image-blocker</link></literal> action) will be sent to the
4253 client as a substitute for the blocked content.
4260 <!-- Boolean, Parameterized, Multi-value -->
4262 <para>Boolean.</para>
4267 <term>Parameter:</term>
4279 The below generic example section is actually part of <filename>default.action</filename>.
4280 It marks all URLs with well-known image file name extensions as images and should
4284 Users will probably only want to use the handle-as-image action in conjunction with
4285 <literal><link linkend="block">block</link></literal>, to block sources of banners, whose URLs don't
4286 reflect the file type, like in the second example section.
4289 Note that you cannot treat HTML pages as images in most cases. For instance, (in-line) ad
4290 frames require an HTML page to be sent, or they won't display properly.
4291 Forcing <literal>handle-as-image</literal> in this situation will not replace the
4292 ad frame with an image, but lead to error messages.
4298 <term>Example usage (sections):</term>
4301 <screen># Generic image extensions:
4304 /.*\.(gif|jpg|jpeg|png|bmp|ico)$
4306 # These don't look like images, but they're banners and should be
4307 # blocked as images:
4309 {+block{Nasty banners.} +handle-as-image}
4310 nasty-banner-server.example.com/junk.cgi\?output=trash
4319 <!-- ~~~~~ New section ~~~~~ -->
4320 <sect3 renderas="sect4" id="hide-accept-language">
4321 <title>hide-accept-language</title>
4327 <term>Typical use:</term>
4329 <para>Pretend to use different language settings.</para>
4334 <term>Effect:</term>
4337 Deletes or replaces the <quote>Accept-Language:</quote> HTTP header in client requests.
4344 <!-- Boolean, Parameterized, Multi-value -->
4346 <para>Parameterized.</para>
4351 <term>Parameter:</term>
4354 Keyword: <quote>block</quote>, or any user defined value.
4363 Faking the browser's language settings can be useful to make a
4364 foreign User-Agent set with
4365 <literal><link linkend="hide-user-agent">hide-user-agent</link></literal>
4369 However some sites with content in different languages check the
4370 <quote>Accept-Language:</quote> to decide which one to take by default.
4371 Sometimes it isn't possible to later switch to another language without
4372 changing the <quote>Accept-Language:</quote> header first.
4375 Therefore it's a good idea to either only change the
4376 <quote>Accept-Language:</quote> header to languages you understand,
4377 or to languages that aren't wide spread.
4380 Before setting the <quote>Accept-Language:</quote> header
4381 to a rare language, you should consider that it helps to
4382 make your requests unique and thus easier to trace.
4383 If you don't plan to change this header frequently,
4384 you should stick to a common language.
4390 <term>Example usage (section):</term>
4393 <screen># Pretend to use Canadian language settings.
4394 {+hide-accept-language{en-ca} \
4395 +hide-user-agent{Mozilla/5.0 (X11; U; OpenBSD i386; en-CA; rv:1.8.0.4) Gecko/20060628 Firefox/1.5.0.4} \
4405 <!-- ~~~~~ New section ~~~~~ -->
4406 <sect3 renderas="sect4" id="hide-content-disposition">
4407 <title>hide-content-disposition</title>
4413 <term>Typical use:</term>
4415 <para>Prevent download menus for content you prefer to view inside the browser.</para>
4420 <term>Effect:</term>
4423 Deletes or replaces the <quote>Content-Disposition:</quote> HTTP header set by some servers.
4430 <!-- Boolean, Parameterized, Multi-value -->
4432 <para>Parameterized.</para>
4437 <term>Parameter:</term>
4440 Keyword: <quote>block</quote>, or any user defined value.
4449 Some servers set the <quote>Content-Disposition:</quote> HTTP header for
4450 documents they assume you want to save locally before viewing them.
4451 The <quote>Content-Disposition:</quote> header contains the file name
4452 the browser is supposed to use by default.
4455 In most browsers that understand this header, it makes it impossible to
4456 <emphasis>just view</emphasis> the document, without downloading it first,
4457 even if it's just a simple text file or an image.
4460 Removing the <quote>Content-Disposition:</quote> header helps
4461 to prevent this annoyance, but some browsers additionally check the
4462 <quote>Content-Type:</quote> header, before they decide if they can
4463 display a document without saving it first. In these cases, you have
4464 to change this header as well, before the browser stops displaying
4468 It is also possible to change the server's file name suggestion
4469 to another one, but in most cases it isn't worth the time to set
4473 This action will probably be removed in the future,
4474 use server-header filters instead.
4480 <term>Example usage:</term>
4483 <screen># Disarm the download link in Sourceforge's patch tracker
4485 +content-type-overwrite{text/plain}\
4486 +hide-content-disposition{block} }
4487 .sourceforge.net/tracker/download\.php</screen>
4495 <!-- ~~~~~ New section ~~~~~ -->
4496 <sect3 renderas="sect4" id="hide-if-modified-since">
4497 <title>hide-if-modified-since</title>
4503 <term>Typical use:</term>
4505 <para>Prevent yet another way to track the user's steps between sessions.</para>
4510 <term>Effect:</term>
4513 Deletes the <quote>If-Modified-Since:</quote> HTTP client header or modifies its value.
4520 <!-- Boolean, Parameterized, Multi-value -->
4522 <para>Parameterized.</para>
4527 <term>Parameter:</term>
4530 Keyword: <quote>block</quote>, or a user defined value that specifies a range of hours.
4539 Removing this header is useful for filter testing, where you want to force a real
4540 reload instead of getting status code <quote>304</quote>, which would cause the
4541 browser to use a cached copy of the page.
4544 Instead of removing the header, <literal>hide-if-modified-since</literal> can
4545 also add or subtract a random amount of time to/from the header's value.
4546 You specify a range of minutes where the random factor should be chosen from and
4547 <application>Privoxy</application> does the rest. A negative value means
4548 subtracting, a positive value adding.
4551 Randomizing the value of the <quote>If-Modified-Since:</quote> makes
4552 it less likely that the server can use the time as a cookie replacement,
4553 but you will run into caching problems if the random range is too high.
4556 It is a good idea to only use a small negative value and let
4557 <literal><link linkend="overwrite-last-modified">overwrite-last-modified</link></literal>
4558 handle the greater changes.
4561 It is also recommended to use this action together with
4562 <literal><link linkend="crunch-if-none-match">crunch-if-none-match</link></literal>,
4563 otherwise it's more or less pointless.
4569 <term>Example usage (section):</term>
4572 <screen># Let the browser revalidate but make tracking based on the time less likely.
4573 {+hide-if-modified-since{-60} \
4574 +overwrite-last-modified{randomize} \
4575 +crunch-if-none-match}
4584 <!-- ~~~~~ New section ~~~~~ -->
4585 <sect3 renderas="sect4" id="hide-from-header">
4586 <title>hide-from-header</title>
4590 <term>Typical use:</term>
4592 <para>Keep your (old and ill) browser from telling web servers your email address</para>
4597 <term>Effect:</term>
4600 Deletes any existing <quote>From:</quote> HTTP header, or replaces it with the
4608 <!-- Boolean, Parameterized, Multi-value -->
4610 <para>Parameterized.</para>
4615 <term>Parameter:</term>
4618 Keyword: <quote>block</quote>, or any user defined value.
4627 The keyword <quote>block</quote> will completely remove the header
4628 (not to be confused with the <literal><link linkend="block">block</link></literal>
4632 Alternately, you can specify any value you prefer to be sent to the web
4633 server. If you do, it is a matter of fairness not to use any address that
4634 is actually used by a real person.
4637 This action is rarely needed, as modern web browsers don't send
4638 <quote>From:</quote> headers anymore.
4644 <term>Example usage:</term>
4647 <screen>+hide-from-header{block}</screen> or
4648 <screen>+hide-from-header{spam-me-senseless@sittingduck.example.com}</screen>
4656 <!-- ~~~~~ New section ~~~~~ -->
4657 <sect3 renderas="sect4" id="hide-referrer">
4658 <title>hide-referrer</title>
4659 <anchor id="hide-referer">
4662 <term>Typical use:</term>
4664 <para>Conceal which link you followed to get to a particular site</para>
4669 <term>Effect:</term>
4672 Deletes the <quote>Referer:</quote> (sic) HTTP header from the client request,
4673 or replaces it with a forged one.
4680 <!-- Boolean, Parameterized, Multi-value -->
4682 <para>Parameterized.</para>
4687 <term>Parameter:</term>
4691 <para><quote>conditional-block</quote> to delete the header completely if the host has changed.</para>
4694 <para><quote>conditional-forge</quote> to forge the header if the host has changed.</para>
4697 <para><quote>block</quote> to delete the header unconditionally.</para>
4700 <para><quote>forge</quote> to pretend to be coming from the homepage of the server we are talking to.</para>
4703 <para>Any other string to set a user defined referrer.</para>
4713 <literal>conditional-block</literal> is the only parameter,
4714 that isn't easily detected in the server's log file. If it blocks the
4715 referrer, the request will look like the visitor used a bookmark or
4716 typed in the address directly.
4719 Leaving the referrer unmodified for requests on the same host
4720 allows the server owner to see the visitor's <quote>click path</quote>,
4721 but in most cases she could also get that information by comparing
4722 other parts of the log file: for example the User-Agent if it isn't
4723 a very common one, or the user's IP address if it doesn't change between
4727 Always blocking the referrer, or using a custom one, can lead to
4728 failures on servers that check the referrer before they answer any
4729 requests, in an attempt to prevent their content from being
4730 embedded or linked to elsewhere.
4733 Both <literal>conditional-block</literal> and <literal>forge</literal>
4734 will work with referrer checks, as long as content and valid referring page
4735 are on the same host. Most of the time that's the case.
4738 <literal>hide-referer</literal> is an alternate spelling of
4739 <literal>hide-referrer</literal> and the two can be can be freely
4740 substituted with each other. (<quote>referrer</quote> is the
4741 correct English spelling, however the HTTP specification has a bug - it
4742 requires it to be spelled as <quote>referer</quote>.)
4748 <term>Example usage:</term>
4751 <screen>+hide-referrer{forge}</screen> or
4752 <screen>+hide-referrer{http://www.yahoo.com/}</screen>
4760 <!-- ~~~~~ New section ~~~~~ -->
4761 <sect3 renderas="sect4" id="hide-user-agent">
4762 <title>hide-user-agent</title>
4766 <term>Typical use:</term>
4768 <para>Try to conceal your type of browser and client operating system</para>
4773 <term>Effect:</term>
4776 Replaces the value of the <quote>User-Agent:</quote> HTTP header
4777 in client requests with the specified value.
4784 <!-- Boolean, Parameterized, Multi-value -->
4786 <para>Parameterized.</para>
4791 <term>Parameter:</term>
4794 Any user-defined string.
4804 This can lead to problems on web sites that depend on looking at this header in
4805 order to customize their content for different browsers (which, by the
4806 way, is <emphasis>NOT</emphasis> the right thing to do: good web sites
4807 work browser-independently).
4811 Using this action in multi-user setups or wherever different types of
4812 browsers will access the same <application>Privoxy</application> is
4813 <emphasis>not recommended</emphasis>. In single-user, single-browser
4814 setups, you might use it to delete your OS version information from
4815 the headers, because it is an invitation to exploit known bugs for your
4816 OS. It is also occasionally useful to forge this in order to access
4817 sites that won't let you in otherwise (though there may be a good
4818 reason in some cases).
4821 More information on known user-agent strings can be found at
4822 <ulink url="http://www.user-agents.org/">http://www.user-agents.org/</ulink>
4824 <ulink url="http://en.wikipedia.org/wiki/User_agent">http://en.wikipedia.org/wiki/User_agent</ulink>.
4830 <term>Example usage:</term>
4833 <screen>+hide-user-agent{Netscape 6.1 (X11; I; Linux 2.4.18 i686)}</screen>
4841 <!-- ~~~~~ New section ~~~~~ -->
4842 <sect3 renderas="sect4" id="limit-connect">
4843 <title>limit-connect</title>
4847 <term>Typical use:</term>
4849 <para>Prevent abuse of <application>Privoxy</application> as a TCP proxy relay or disable SSL for untrusted sites</para>
4854 <term>Effect:</term>
4857 Specifies to which ports HTTP CONNECT requests are allowable.
4864 <!-- Boolean, Parameterized, Multi-value -->
4866 <para>Parameterized.</para>
4871 <term>Parameter:</term>
4874 A comma-separated list of ports or port ranges (the latter using dashes, with the minimum
4875 defaulting to 0 and the maximum to 65K).
4884 By default, i.e. if no <literal>limit-connect</literal> action applies,
4885 <application>Privoxy</application> allows HTTP CONNECT requests to all
4886 ports. Use <literal>limit-connect</literal> if fine-grained control
4887 is desired for some or all destinations.
4890 The CONNECT methods exists in HTTP to allow access to secure websites
4891 (<quote>https://</quote> URLs) through proxies. It works very simply:
4892 the proxy connects to the server on the specified port, and then
4893 short-circuits its connections to the client and to the remote server.
4894 This means CONNECT-enabled proxies can be used as TCP relays very easily.
4897 <application>Privoxy</application> relays HTTPS traffic without seeing
4898 the decoded content. Websites can leverage this limitation to circumvent &my-app;'s
4899 filters. By specifying an invalid port range you can disable HTTPS entirely.
4905 <term>Example usages:</term>
4907 <!-- I had trouble getting the spacing to look right in my browser -->
4908 <!-- I probably have the wrong font setup, bollocks. -->
4909 <!-- Apparently the emphasis tag uses a proportional font no matter what -->
4911 <screen>+limit-connect{443} # Port 443 is OK.
4912 +limit-connect{80,443} # Ports 80 and 443 are OK.
4913 +limit-connect{-3, 7, 20-100, 500-} # Ports less than 3, 7, 20 to 100 and above 500 are OK.
4914 +limit-connect{-} # All ports are OK
4915 +limit-connect{,} # No HTTPS/SSL traffic is allowed</screen>
4923 <!-- ~~~~~ New section ~~~~~ -->
4924 <sect3 renderas="sect4" id="limit-cookie-lifetime">
4925 <title>limit-cookie-lifetime</title>
4929 <term>Typical use:</term>
4931 <para>Limit the lifetime of HTTP cookies to a couple of minutes or hours.</para>
4936 <term>Effect:</term>
4939 Overwrites the expires field in Set-Cookie server headers if it's above the specified limit.
4946 <!-- Boolean, Parameterized, Multi-value -->
4948 <para>Parameterized.</para>
4953 <term>Parameter:</term>
4956 The lifetime limit in minutes, or 0.
4965 This action reduces the lifetime of HTTP cookies coming from the
4966 server to the specified number of minutes, starting from the time
4967 the cookie passes Privoxy.
4970 Cookies with a lifetime below the limit are not modified.
4971 The lifetime of session cookies is set to the specified limit.
4974 The effect of this action depends on the server.
4977 In case of servers which refresh their cookies with each response
4978 (or at least frequently), the lifetime limit set by this action
4980 Thus, a session associated with the cookie continues to work with
4981 this action enabled, as long as a new request is made before the
4982 last limit set is reached.
4985 However, some servers send their cookies once, with a lifetime of several
4986 years (the year 2037 is a popular choice), and do not refresh them
4987 until a certain event in the future, for example the user logging out.
4988 In this case this action may limit the absolute lifetime of the session,
4989 even if requests are made frequently.
4992 If the parameter is <quote>0</quote>, this action behaves like
4993 <literal><link linkend="session-cookies-only">session-cookies-only</link></literal>.
4999 <term>Example usages:</term>
5002 <screen>+limit-cookie-lifetime{60}
5010 <!-- ~~~~~ New section ~~~~~ -->
5011 <sect3 renderas="sect4" id="prevent-compression">
5012 <title>prevent-compression</title>
5016 <term>Typical use:</term>
5019 Ensure that servers send the content uncompressed, so it can be
5020 passed through <literal><link linkend="filter">filter</link></literal>s.
5026 <term>Effect:</term>
5029 Removes the Accept-Encoding header which can be used to ask for compressed transfer.
5036 <!-- Boolean, Parameterized, Multi-value -->
5038 <para>Boolean.</para>
5043 <term>Parameter:</term>
5055 More and more websites send their content compressed by default, which
5056 is generally a good idea and saves bandwidth. But the <literal><link
5057 linkend="filter">filter</link></literal> and
5058 <literal><link linkend="deanimate-gifs">deanimate-gifs</link></literal>
5059 actions need access to the uncompressed data.
5062 When compiled with zlib support (available since &my-app; 3.0.7), content that should be
5063 filtered is decompressed on-the-fly and you don't have to worry about this action.
5064 If you are using an older &my-app; version, or one that hasn't been compiled with zlib
5065 support, this action can be used to convince the server to send the content uncompressed.
5068 Most text-based instances compress very well, the size is seldom decreased by less than 50%,
5069 for markup-heavy instances like news feeds saving more than 90% of the original size isn't
5073 Not using compression will therefore slow down the transfer, and you should only
5074 enable this action if you really need it. As of &my-app; 3.0.7 it's disabled in all
5075 predefined action settings.
5078 Note that some (rare) ill-configured sites don't handle requests for uncompressed
5079 documents correctly. Broken PHP applications tend to send an empty document body,
5080 some IIS versions only send the beginning of the content. If you enable
5081 <literal>prevent-compression</literal> per default, you might want to add
5082 exceptions for those sites. See the example for how to do that.
5088 <term>Example usage (sections):</term>
5092 # Selectively turn off compression, and enable a filter
5094 { +filter{tiny-textforms} +prevent-compression }
5095 # Match only these sites
5100 # Or instead, we could set a universal default:
5102 { +prevent-compression }
5105 # Then maybe make exceptions for broken sites:
5107 { -prevent-compression }
5108 .compusa.com/</screen>
5117 <!-- ~~~~~ New section ~~~~~ -->
5118 <sect3 renderas="sect4" id="overwrite-last-modified">
5119 <title>overwrite-last-modified</title>
5125 <term>Typical use:</term>
5127 <para>Prevent yet another way to track the user's steps between sessions.</para>
5132 <term>Effect:</term>
5135 Deletes the <quote>Last-Modified:</quote> HTTP server header or modifies its value.
5142 <!-- Boolean, Parameterized, Multi-value -->
5144 <para>Parameterized.</para>
5149 <term>Parameter:</term>
5152 One of the keywords: <quote>block</quote>, <quote>reset-to-request-time</quote>
5153 and <quote>randomize</quote>
5162 Removing the <quote>Last-Modified:</quote> header is useful for filter
5163 testing, where you want to force a real reload instead of getting status
5164 code <quote>304</quote>, which would cause the browser to reuse the old
5165 version of the page.
5168 The <quote>randomize</quote> option overwrites the value of the
5169 <quote>Last-Modified:</quote> header with a randomly chosen time
5170 between the original value and the current time. In theory the server
5171 could send each document with a different <quote>Last-Modified:</quote>
5172 header to track visits without using cookies. <quote>Randomize</quote>
5173 makes it impossible and the browser can still revalidate cached documents.
5176 <quote>reset-to-request-time</quote> overwrites the value of the
5177 <quote>Last-Modified:</quote> header with the current time. You could use
5178 this option together with
5179 <literal><link linkend="hide-if-modified-since">hide-if-modified-since</link></literal>
5180 to further customize your random range.
5183 The preferred parameter here is <quote>randomize</quote>. It is safe
5184 to use, as long as the time settings are more or less correct.
5185 If the server sets the <quote>Last-Modified:</quote> header to the time
5186 of the request, the random range becomes zero and the value stays the same.
5187 Therefore you should later randomize it a second time with
5188 <literal><link linkend="hide-if-modified-since">hided-if-modified-since</link></literal>,
5192 It is also recommended to use this action together with
5193 <literal><link linkend="crunch-if-none-match">crunch-if-none-match</link></literal>.
5199 <term>Example usage:</term>
5202 <screen># Let the browser revalidate without being tracked across sessions
5203 { +hide-if-modified-since{-60} \
5204 +overwrite-last-modified{randomize} \
5205 +crunch-if-none-match}
5214 <!-- ~~~~~ New section ~~~~~ -->
5215 <sect3 renderas="sect4" id="redirect">
5216 <title>redirect</title>
5222 <term>Typical use:</term>
5225 Redirect requests to other sites.
5231 <term>Effect:</term>
5234 Convinces the browser that the requested document has been moved
5235 to another location and the browser should get it from there.
5242 <!-- Boolean, Parameterized, Multi-value -->
5244 <para>Parameterized</para>
5249 <term>Parameter:</term>
5252 An absolute URL or a single pcrs command.
5261 Requests to which this action applies are answered with a
5262 HTTP redirect to URLs of your choosing. The new URL is
5263 either provided as parameter, or derived by applying a
5264 single pcrs command to the original URL.
5267 The syntax for pcrs commands is documented in the
5268 <link linkend="filter-file">filter file</link> section.
5271 This action will be ignored if you use it together with
5272 <literal><link linkend="block">block</link></literal>.
5273 It can be combined with
5274 <literal><link linkend="fast-redirects">fast-redirects{check-decoded-url}</link></literal>
5275 to redirect to a decoded version of a rewritten URL.
5278 Use this action carefully, make sure not to create redirection loops
5279 and be aware that using your own redirects might make it
5280 possible to fingerprint your requests.
5283 In case of problems with your redirects, or simply to watch
5284 them working, enable <link linkend="DEBUG">debug 128</link>.
5290 <term>Example usages:</term>
5293 <screen># Replace example.com's style sheet with another one
5294 { +redirect{http://localhost/css-replacements/example.com.css} }
5295 example.com/stylesheet\.css
5297 # Create a short, easy to remember nickname for a favorite site
5298 # (relies on the browser to accept and forward invalid URLs to &my-app;)
5299 { +redirect{http://www.privoxy.org/user-manual/actions-file.html} }
5302 # Always use the expanded view for Undeadly.org articles
5303 # (Note the $ at the end of the URL pattern to make sure
5304 # the request for the rewritten URL isn't redirected as well)
5305 {+redirect{s@$@&mode=expanded@}}
5306 undeadly.org/cgi\?action=article&sid=\d*$
5308 # Redirect Google search requests to MSN
5309 {+redirect{s@^http://[^/]*/search\?q=([^&]*).*@http://search.msn.com/results.aspx?q=$1@}}
5312 # Redirect MSN search requests to Yahoo
5313 {+redirect{s@^http://[^/]*/results\.aspx\?q=([^&]*).*@http://search.yahoo.com/search?p=$1@}}
5314 search.msn.com//results\.aspx\?q=
5316 # Redirect remote requests for this manual
5317 # to the local version delivered by Privoxy
5318 {+redirect{s@^http://www@http://config@}}
5319 www.privoxy.org/user-manual/</screen>
5328 <!-- ~~~~~ New section ~~~~~ -->
5329 <sect3 renderas="sect4" id="server-header-filter">
5330 <title>server-header-filter</title>
5334 <term>Typical use:</term>
5337 Rewrite or remove single server headers.
5343 <term>Effect:</term>
5346 All server headers to which this action applies are filtered on-the-fly
5347 through the specified regular expression based substitutions.
5354 <!-- boolean, parameterized, Multi-value -->
5356 <para>Parameterized.</para>
5361 <term>Parameter:</term>
5364 The name of a server-header filter, as defined in one of the
5365 <link linkend="filter-file">filter files</link>.
5374 Server-header filters are applied to each header on its own, not to
5375 all at once. This makes it easier to diagnose problems, but on the downside
5376 you can't write filters that only change header x if header y's value is z.
5377 You can do that by using tags though.
5380 Server-header filters are executed after the other header actions have finished
5381 and use their output as input.
5384 Please refer to the <link linkend="filter-file">filter file chapter</link>
5385 to learn which server-header filters are available by default, and how to
5392 <term>Example usage (section):</term>
5396 {+server-header-filter{html-to-xml}}
5397 example.org/xml-instance-that-is-delivered-as-html
5399 {+server-header-filter{xml-to-html}}
5400 example.org/instance-that-is-delivered-as-xml-but-is-not
5410 <!-- ~~~~~ New section ~~~~~ -->
5411 <sect3 renderas="sect4" id="server-header-tagger">
5412 <title>server-header-tagger</title>
5416 <term>Typical use:</term>
5419 Enable or disable filters based on the Content-Type header.
5425 <term>Effect:</term>
5428 Server headers to which this action applies are filtered on-the-fly through
5429 the specified regular expression based substitutions, the result is used as
5437 <!-- boolean, parameterized, Multi-value -->
5439 <para>Parameterized.</para>
5444 <term>Parameter:</term>
5447 The name of a server-header tagger, as defined in one of the
5448 <link linkend="filter-file">filter files</link>.
5457 Server-header taggers are applied to each header on its own,
5458 and as the header isn't modified, each tagger <quote>sees</quote>
5462 Server-header taggers are executed before all other header actions
5463 that modify server headers. Their tags can be used to control
5464 all of the other server-header actions, the content filters
5465 and the crunch actions (<link linkend="redirect">redirect</link>
5466 and <link linkend="block">block</link>).
5469 Obviously crunching based on tags created by server-header taggers
5470 doesn't prevent the request from showing up in the server's log file.
5477 <term>Example usage (section):</term>
5481 # Tag every request with the content type declared by the server
5482 {+server-header-tagger{content-type}}
5493 <!-- ~~~~~ New section ~~~~~ -->
5494 <sect3 renderas="sect4" id="session-cookies-only">
5495 <title>session-cookies-only</title>
5499 <term>Typical use:</term>
5502 Allow only temporary <quote>session</quote> cookies (for the current
5503 browser session <emphasis>only</emphasis>).
5509 <term>Effect:</term>
5512 Deletes the <quote>expires</quote> field from <quote>Set-Cookie:</quote>
5513 server headers. Most browsers will not store such cookies permanently and
5514 forget them in between sessions.
5521 <!-- Boolean, Parameterized, Multi-value -->
5523 <para>Boolean.</para>
5528 <term>Parameter:</term>
5540 This is less strict than <literal><link linkend="crunch-incoming-cookies">crunch-incoming-cookies</link></literal> /
5541 <literal><link linkend="crunch-outgoing-cookies">crunch-outgoing-cookies</link></literal> and allows you to browse
5542 websites that insist or rely on setting cookies, without compromising your privacy too badly.
5545 Most browsers will not permanently store cookies that have been processed by
5546 <literal>session-cookies-only</literal> and will forget about them between sessions.
5547 This makes profiling cookies useless, but won't break sites which require cookies so
5548 that you can log in for transactions. This is generally turned on for all
5549 sites, and is the recommended setting.
5552 It makes <emphasis>no sense at all</emphasis> to use <literal>session-cookies-only</literal>
5553 together with <literal><link linkend="crunch-incoming-cookies">crunch-incoming-cookies</link></literal> or
5554 <literal><link linkend="crunch-outgoing-cookies">crunch-outgoing-cookies</link></literal>. If you do, cookies
5555 will be plainly killed.
5558 Note that it is up to the browser how it handles such cookies without an <quote>expires</quote>
5559 field. If you use an exotic browser, you might want to try it out to be sure.
5562 This setting also has no effect on cookies that may have been stored
5563 previously by the browser before starting <application>Privoxy</application>.
5564 These would have to be removed manually.
5567 <application>Privoxy</application> also uses
5568 the <link linkend="filter-content-cookies">content-cookies filter</link>
5569 to block some types of cookies. Content cookies are not effected by
5570 <literal>session-cookies-only</literal>.
5576 <term>Example usage:</term>
5579 <screen>+session-cookies-only</screen>
5587 <!-- ~~~~~ New section ~~~~~ -->
5588 <sect3 renderas="sect4" id="set-image-blocker">
5589 <title>set-image-blocker</title>
5593 <term>Typical use:</term>
5595 <para>Choose the replacement for blocked images</para>
5600 <term>Effect:</term>
5603 This action alone doesn't do anything noticeable. If <emphasis>both</emphasis>
5604 <literal><link linkend="block">block</link></literal> <emphasis>and</emphasis> <literal><link
5605 linkend="handle-as-image">handle-as-image</link></literal> <emphasis>also</emphasis>
5606 apply, i.e. if the request is to be blocked as an image,
5607 <emphasis>then</emphasis> the parameter of this action decides what will be
5608 sent as a replacement.
5615 <!-- Boolean, Parameterized, Multi-value -->
5617 <para>Parameterized.</para>
5622 <term>Parameter:</term>
5627 <quote>pattern</quote> to send a built-in checkerboard pattern image. The image is visually
5628 decent, scales very well, and makes it obvious where banners were busted.
5633 <quote>blank</quote> to send a built-in transparent image. This makes banners disappear
5634 completely, but makes it hard to detect where <application>Privoxy</application> has blocked
5635 images on a given page and complicates troubleshooting if <application>Privoxy</application>
5636 has blocked innocent images, like navigation icons.
5641 <quote><replaceable class="parameter">target-url</replaceable></quote> to
5642 send a redirect to <replaceable class="parameter">target-url</replaceable>. You can redirect
5643 to any image anywhere, even in your local filesystem via <quote>file:///</quote> URL.
5644 (But note that not all browsers support redirecting to a local file system).
5647 A good application of redirects is to use special <application>Privoxy</application>-built-in
5648 URLs, which send the built-in images, as <replaceable class="parameter">target-url</replaceable>.
5649 This has the same visual effect as specifying <quote>blank</quote> or <quote>pattern</quote> in
5650 the first place, but enables your browser to cache the replacement image, instead of requesting
5651 it over and over again.
5662 The URLs for the built-in images are <quote>http://config.privoxy.org/send-banner?type=<replaceable
5663 class="parameter">type</replaceable></quote>, where <replaceable class="parameter">type</replaceable> is
5664 either <quote>blank</quote> or <quote>pattern</quote>.
5667 There is a third (advanced) type, called <quote>auto</quote>. It is <emphasis>NOT</emphasis> to be
5668 used in <literal>set-image-blocker</literal>, but meant for use from <link linkend="filter-file">filters</link>.
5669 Auto will select the type of image that would have applied to the referring page, had it been an image.
5675 <term>Example usage:</term>
5681 <screen>+set-image-blocker{pattern}</screen>
5684 Redirect to the BSD daemon:
5687 <screen>+set-image-blocker{http://www.freebsd.org/gifs/dae_up3.gif}</screen>
5690 Redirect to the built-in pattern for better caching:
5693 <screen>+set-image-blocker{http://config.privoxy.org/send-banner?type=pattern}</screen>
5701 <!-- ~~~~~ New section ~~~~~ -->
5703 <title>Summary</title>
5705 Note that many of these actions have the potential to cause a page to
5706 misbehave, possibly even not to display at all. There are many ways
5707 a site designer may choose to design his site, and what HTTP header
5708 content, and other criteria, he may depend on. There is no way to have hard
5709 and fast rules for all sites. See the <link
5710 linkend="ACTIONSANAT">Appendix</link> for a brief example on troubleshooting
5716 <!-- ~~~~~ New section ~~~~~ -->
5717 <sect2 id="aliases">
5718 <title>Aliases</title>
5720 Custom <quote>actions</quote>, known to <application>Privoxy</application>
5721 as <quote>aliases</quote>, can be defined by combining other actions.
5722 These can in turn be invoked just like the built-in actions.
5723 Currently, an alias name can contain any character except space, tab,
5725 <quote>{</quote> and <quote>}</quote>, but we <emphasis>strongly
5726 recommend</emphasis> that you only use <quote>a</quote> to <quote>z</quote>,
5727 <quote>0</quote> to <quote>9</quote>, <quote>+</quote>, and <quote>-</quote>.
5728 Alias names are not case sensitive, and are not required to start with a
5729 <quote>+</quote> or <quote>-</quote> sign, since they are merely textually
5733 Aliases can be used throughout the actions file, but they <emphasis>must be
5734 defined in a special section at the top of the file!</emphasis>
5735 And there can only be one such section per actions file. Each actions file may
5736 have its own alias section, and the aliases defined in it are only visible
5740 There are two main reasons to use aliases: One is to save typing for frequently
5741 used combinations of actions, the other one is a gain in flexibility: If you
5742 decide once how you want to handle shops by defining an alias called
5743 <quote>shop</quote>, you can later change your policy on shops in
5744 <emphasis>one</emphasis> place, and your changes will take effect everywhere
5745 in the actions file where the <quote>shop</quote> alias is used. Calling aliases
5746 by their purpose also makes your actions files more readable.
5749 Currently, there is one big drawback to using aliases, though:
5750 <application>Privoxy</application>'s built-in web-based action file
5751 editor honors aliases when reading the actions files, but it expands
5752 them before writing. So the effects of your aliases are of course preserved,
5753 but the aliases themselves are lost when you edit sections that use aliases
5758 Now let's define some aliases...
5763 # Useful custom aliases we can use later.
5765 # Note the (required!) section header line and that this section
5766 # must be at the top of the actions file!
5770 # These aliases just save typing later:
5771 # (Note that some already use other aliases!)
5773 +crunch-all-cookies = +<link linkend="CRUNCH-INCOMING-COOKIES">crunch-incoming-cookies</link> +<link linkend="CRUNCH-OUTGOING-COOKIES">crunch-outgoing-cookies</link>
5774 -crunch-all-cookies = -<link linkend="CRUNCH-INCOMING-COOKIES">crunch-incoming-cookies</link> -<link linkend="CRUNCH-OUTGOING-COOKIES">crunch-outgoing-cookies</link>
5775 +block-as-image = +block{Blocked image.} +handle-as-image
5776 allow-all-cookies = -crunch-all-cookies -<link linkend="SESSION-COOKIES-ONLY">session-cookies-only</link> -<link linkend="FILTER-CONTENT-COOKIES">filter{content-cookies}</link>
5778 # These aliases define combinations of actions
5779 # that are useful for certain types of sites:
5781 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>
5783 shop = -crunch-all-cookies -<link linkend="FILTER-ALL-POPUPS">filter{all-popups}</link>
5785 # Short names for other aliases, for really lazy people ;-)
5787 c0 = +crunch-all-cookies
5788 c1 = -crunch-all-cookies</screen>
5792 ...and put them to use. These sections would appear in the lower part of an
5793 actions file and define exceptions to the default actions (as specified further
5794 up for the <quote>/</quote> pattern):
5799 # These sites are either very complex or very keen on
5800 # user data and require minimal interference to work:
5803 .office.microsoft.com
5804 .windowsupdate.microsoft.com
5805 # Gmail is really mail.google.com, not gmail.com
5809 # Allow cookies (for setting and retrieving your customer data)
5813 .worldpay.com # for quietpc.com
5816 # These shops require pop-ups:
5818 {-filter{all-popups} -filter{unsolicited-popups}}
5820 .overclockers.co.uk</screen>
5824 Aliases like <quote>shop</quote> and <quote>fragile</quote> are typically used for
5825 <quote>problem</quote> sites that require more than one action to be disabled
5826 in order to function properly.
5832 <!-- ~~~~~ New section ~~~~~ -->
5833 <sect2 id="act-examples">
5834 <title>Actions Files Tutorial</title>
5836 The above chapters have shown <link linkend="actions-file">which actions files
5837 there are and how they are organized</link>, how actions are <link
5838 linkend="actions">specified</link> and <link linkend="actions-apply">applied
5839 to URLs</link>, how <link linkend="af-patterns">patterns</link> work, and how to
5840 define and use <link linkend="aliases">aliases</link>. Now, let's look at an
5841 example <filename>match-all.action</filename>, <filename>default.action</filename>
5842 and <filename>user.action</filename> file and see how all these pieces come together:
5846 <title>match-all.action</title>
5848 Remember <emphasis>all actions are disabled when matching starts</emphasis>,
5849 so we have to explicitly enable the ones we want.
5853 While the <filename>match-all.action</filename> file only contains a
5854 single section, it is probably the most important one. It has only one
5855 pattern, <quote><literal>/</literal></quote>, but this pattern
5856 <link linkend="af-patterns">matches all URLs</link>. Therefore, the set of
5857 actions used in this <quote>default</quote> section <emphasis>will
5858 be applied to all requests as a start</emphasis>. It can be partly or
5859 wholly overridden by other actions files like <filename>default.action</filename>
5860 and <filename>user.action</filename>, but it will still be largely responsible
5861 for your overall browsing experience.
5865 Again, at the start of matching, all actions are disabled, so there is
5866 no need to disable any actions here. (Remember: a <quote>+</quote>
5867 preceding the action name enables the action, a <quote>-</quote> disables!).
5868 Also note how this long line has been made more readable by splitting it into
5869 multiple lines with line continuation.
5875 +<link linkend="CHANGE-X-FORWARDED-FOR">change-x-forwarded-for{block}</link> \
5876 +<link linkend="HIDE-FROM-HEADER">hide-from-header{block}</link> \
5877 +<link linkend="SET-IMAGE-BLOCKER">set-image-blocker{pattern}</link> \
5884 The default behavior is now set.
5889 <title>default.action</title>
5892 If you aren't a developer, there's no need for you to edit the
5893 <filename>default.action</filename> file. It is maintained by
5894 the &my-app; developers and if you disagree with some of the
5895 sections, you should overrule them in your <filename>user.action</filename>.
5899 Understanding the <filename>default.action</filename> file can
5900 help you with your <filename>user.action</filename>, though.
5904 The first section in this file is a special section for internal use
5905 that prevents older &my-app; versions from reading the file:
5910 ##########################################################################
5911 # Settings -- Don't change! For internal Privoxy use ONLY.
5912 ##########################################################################
5914 for-privoxy-version=3.0.11</screen>
5918 After that comes the (optional) alias section. We'll use the example
5919 section from the above <link linkend="aliases">chapter on aliases</link>,
5920 that also explains why and how aliases are used:
5925 ##########################################################################
5927 ##########################################################################
5930 # These aliases just save typing later:
5931 # (Note that some already use other aliases!)
5933 +crunch-all-cookies = +<link linkend="CRUNCH-INCOMING-COOKIES">crunch-incoming-cookies</link> +<link linkend="CRUNCH-OUTGOING-COOKIES">crunch-outgoing-cookies</link>
5934 -crunch-all-cookies = -<link linkend="CRUNCH-INCOMING-COOKIES">crunch-incoming-cookies</link> -<link linkend="CRUNCH-OUTGOING-COOKIES">crunch-outgoing-cookies</link>
5935 +block-as-image = +block{Blocked image.} +handle-as-image
5936 mercy-for-cookies = -crunch-all-cookies -<link linkend="SESSION-COOKIES-ONLY">session-cookies-only</link> -<link linkend="FILTER-CONTENT-COOKIES">filter{content-cookies}</link>
5938 # These aliases define combinations of actions
5939 # that are useful for certain types of sites:
5941 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>
5942 shop = -crunch-all-cookies -<link linkend="FILTER-ALL-POPUPS">filter{all-popups}</link></screen>
5946 The first of our specialized sections is concerned with <quote>fragile</quote>
5947 sites, i.e. sites that require minimum interference, because they are either
5948 very complex or very keen on tracking you (and have mechanisms in place that
5949 make them unusable for people who avoid being tracked). We will simply use
5950 our pre-defined <literal>fragile</literal> alias instead of stating the list
5951 of actions explicitly:
5956 ##########################################################################
5957 # Exceptions for sites that'll break under the default action set:
5958 ##########################################################################
5960 # "Fragile" Use a minimum set of actions for these sites (see alias above):
5963 .office.microsoft.com # surprise, surprise!
5964 .windowsupdate.microsoft.com
5965 mail.google.com</screen>
5969 Shopping sites are not as fragile, but they typically
5970 require cookies to log in, and pop-up windows for shopping
5971 carts or item details. Again, we'll use a pre-defined alias:
5980 .worldpay.com # for quietpc.com
5982 .scan.co.uk</screen>
5986 The <literal><link linkend="FAST-REDIRECTS">fast-redirects</link></literal>
5987 action, which may have been enabled in <filename>match-all.action</filename>,
5988 breaks some sites. So disable it for popular sites where we know it misbehaves:
5993 { -<link linkend="FAST-REDIRECTS">fast-redirects</link> }
5997 .altavista.com/.*(like|url|link):http
5998 .altavista.com/trans.*urltext=http
5999 .nytimes.com</screen>
6003 It is important that <application>Privoxy</application> knows which
6004 URLs belong to images, so that <emphasis>if</emphasis> they are to
6005 be blocked, a substitute image can be sent, rather than an HTML page.
6006 Contacting the remote site to find out is not an option, since it
6007 would destroy the loading time advantage of banner blocking, and it
6008 would feed the advertisers information about you. We can mark any
6009 URL as an image with the <literal><link
6010 linkend="handle-as-image">handle-as-image</link></literal> action,
6011 and marking all URLs that end in a known image file extension is a
6017 ##########################################################################
6019 ##########################################################################
6021 # Define which file types will be treated as images, in case they get
6022 # blocked further down this file:
6024 { +<link linkend="HANDLE-AS-IMAGE">handle-as-image</link> }
6025 /.*\.(gif|jpe?g|png|bmp|ico)$</screen>
6029 And then there are known banner sources. They often use scripts to
6030 generate the banners, so it won't be visible from the URL that the
6031 request is for an image. Hence we block them <emphasis>and</emphasis>
6032 mark them as images in one go, with the help of our
6033 <literal>+block-as-image</literal> alias defined above. (We could of
6034 course just as well use <literal>+<link linkend="block">block</link>
6035 +<link linkend="handle-as-image">handle-as-image</link></literal> here.)
6036 Remember that the type of the replacement image is chosen by the
6037 <literal><link linkend="set-image-blocker">set-image-blocker</link></literal>
6038 action. Since all URLs have matched the default section with its
6039 <literal>+<link linkend="set-image-blocker">set-image-blocker</link>{pattern}</literal>
6040 action before, it still applies and needn't be repeated:
6045 # Known ad generators:
6050 .ad.*.doubleclick.net
6051 .a.yimg.com/(?:(?!/i/).)*$
6052 .a[0-9].yimg.com/(?:(?!/i/).)*$
6058 One of the most important jobs of <application>Privoxy</application>
6059 is to block banners. Many of these can be <quote>blocked</quote>
6060 by the <literal><link linkend="filter">filter</link>{banners-by-size}</literal>
6061 action, which we enabled above, and which deletes the references to banner
6062 images from the pages while they are loaded, so the browser doesn't request
6063 them anymore, and hence they don't need to be blocked here. But this naturally
6064 doesn't catch all banners, and some people choose not to use filters, so we
6065 need a comprehensive list of patterns for banner URLs here, and apply the
6066 <literal><link linkend="block">block</link></literal> action to them.
6069 First comes many generic patterns, which do most of the work, by
6070 matching typical domain and path name components of banners. Then comes
6071 a list of individual patterns for specific sites, which is omitted here
6072 to keep the example short:
6077 ##########################################################################
6078 # Block these fine banners:
6079 ##########################################################################
6080 { <link linkend="BLOCK">+block{Banner ads.}</link> }
6088 /.*count(er)?\.(pl|cgi|exe|dll|asp|php[34]?)
6089 /(?:.*/)?(publicite|werbung|rekla(ma|me|am)|annonse|maino(kset|nta|s)?)/
6091 # Site-specific patterns (abbreviated):
6093 .hitbox.com</screen>
6097 It's quite remarkable how many advertisers actually call their banner
6098 servers ads.<replaceable>company</replaceable>.com, or call the directory
6099 in which the banners are stored simply <quote>banners</quote>. So the above
6100 generic patterns are surprisingly effective.
6103 But being very generic, they necessarily also catch URLs that we don't want
6104 to block. The pattern <literal>.*ads.</literal> e.g. catches
6105 <quote>nasty-<emphasis>ads</emphasis>.nasty-corp.com</quote> as intended,
6106 but also <quote>downlo<emphasis>ads</emphasis>.sourcefroge.net</quote> or
6107 <quote><emphasis>ads</emphasis>l.some-provider.net.</quote> So here come some
6108 well-known exceptions to the <literal>+<link linkend="BLOCK">block</link></literal>
6112 Note that these are exceptions to exceptions from the default! Consider the URL
6113 <quote>downloads.sourcefroge.net</quote>: Initially, all actions are deactivated,
6114 so it wouldn't get blocked. Then comes the defaults section, which matches the
6115 URL, but just deactivates the <literal><link linkend="BLOCK">block</link></literal>
6116 action once again. Then it matches <literal>.*ads.</literal>, an exception to the
6117 general non-blocking policy, and suddenly
6118 <literal><link linkend="BLOCK">+block</link></literal> applies. And now, it'll match
6119 <literal>.*loads.</literal>, where <literal><link linkend="BLOCK">-block</link></literal>
6120 applies, so (unless it matches <emphasis>again</emphasis> further down) it ends up
6121 with no <literal><link linkend="BLOCK">block</link></literal> action applying.
6126 ##########################################################################
6127 # Save some innocent victims of the above generic block patterns:
6128 ##########################################################################
6132 { -<link linkend="BLOCK">block</link> }
6133 adv[io]*. # (for advogato.org and advice.*)
6134 adsl. # (has nothing to do with ads)
6135 adobe. # (has nothing to do with ads either)
6136 ad[ud]*. # (adult.* and add.*)
6137 .edu # (universities don't host banners (yet!))
6138 .*loads. # (downloads, uploads etc)
6146 www.globalintersec.com/adv # (adv = advanced)
6147 www.ugu.com/sui/ugu/adv</screen>
6151 Filtering source code can have nasty side effects,
6152 so make an exception for our friends at sourceforge.net,
6153 and all paths with <quote>cvs</quote> in them. Note that
6154 <literal>-<link linkend="FILTER">filter</link></literal>
6155 disables <emphasis>all</emphasis> filters in one fell swoop!
6160 # Don't filter code!
6162 { -<link linkend="FILTER">filter</link> }
6167 .sourceforge.net</screen>
6171 The actual <filename>default.action</filename> is of course much more
6172 comprehensive, but we hope this example made clear how it works.
6177 <sect3><title>user.action</title>
6180 So far we are painting with a broad brush by setting general policies,
6181 which would be a reasonable starting point for many people. Now,
6182 you might want to be more specific and have customized rules that
6183 are more suitable to your personal habits and preferences. These would
6184 be for narrowly defined situations like your ISP or your bank, and should
6185 be placed in <filename>user.action</filename>, which is parsed after all other
6186 actions files and hence has the last word, over-riding any previously
6187 defined actions. <filename>user.action</filename> is also a
6188 <emphasis>safe</emphasis> place for your personal settings, since
6189 <filename>default.action</filename> is actively maintained by the
6190 <application>Privoxy</application> developers and you'll probably want
6191 to install updated versions from time to time.
6195 So let's look at a few examples of things that one might typically do in
6196 <filename>user.action</filename>:
6200 <!-- brief sample user.action here -->
6204 # My user.action file. <fred@example.com></screen>
6208 As <link linkend="aliases">aliases</link> are local to the actions
6209 file that they are defined in, you can't use the ones from
6210 <filename>default.action</filename>, unless you repeat them here:
6215 # Aliases are local to the file they are defined in.
6216 # (Re-)define aliases for this file:
6220 # These aliases just save typing later, and the alias names should
6221 # be self explanatory.
6223 +crunch-all-cookies = +crunch-incoming-cookies +crunch-outgoing-cookies
6224 -crunch-all-cookies = -crunch-incoming-cookies -crunch-outgoing-cookies
6225 allow-all-cookies = -crunch-all-cookies -session-cookies-only
6226 allow-popups = -filter{all-popups}
6227 +block-as-image = +block{Blocked as image.} +handle-as-image
6228 -block-as-image = -block
6230 # These aliases define combinations of actions that are useful for
6231 # certain types of sites:
6233 fragile = -block -crunch-all-cookies -filter -fast-redirects -hide-referrer
6234 shop = -crunch-all-cookies allow-popups
6236 # Allow ads for selected useful free sites:
6238 allow-ads = -block -filter{banners-by-size} -filter{banners-by-link}
6240 # Alias for specific file types that are text, but might have conflicting
6241 # MIME types. We want the browser to force these to be text documents.
6242 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>
6247 Say you have accounts on some sites that you visit regularly, and
6248 you don't want to have to log in manually each time. So you'd like
6249 to allow persistent cookies for these sites. The
6250 <literal>allow-all-cookies</literal> alias defined above does exactly
6251 that, i.e. it disables crunching of cookies in any direction, and the
6252 processing of cookies to make them only temporary.
6257 { allow-all-cookies }
6261 .redhat.com</screen>
6265 Your bank is allergic to some filter, but you don't know which, so you disable them all:
6270 { -<link linkend="FILTER">filter</link> }
6271 .your-home-banking-site.com</screen>
6275 Some file types you may not want to filter for various reasons:
6280 # Technical documentation is likely to contain strings that might
6281 # erroneously get altered by the JavaScript-oriented filters:
6286 # And this stupid host sends streaming video with a wrong MIME type,
6287 # so that Privoxy thinks it is getting HTML and starts filtering:
6289 stupid-server.example.com/</screen>
6293 Example of a simple <link linkend="BLOCK">block</link> action. Say you've
6294 seen an ad on your favourite page on example.com that you want to get rid of.
6295 You have right-clicked the image, selected <quote>copy image location</quote>
6296 and pasted the URL below while removing the leading http://, into a
6297 <literal>{ +block{} }</literal> section. Note that <literal>{ +handle-as-image
6298 }</literal> need not be specified, since all URLs ending in
6299 <literal>.gif</literal> will be tagged as images by the general rules as set
6300 in default.action anyway:
6305 { +<link linkend="BLOCK">block</link>{Nasty ads.} }
6306 www.example.com/nasty-ads/sponsor\.gif
6307 another.example.net/more/junk/here/</screen>
6311 The URLs of dynamically generated banners, especially from large banner
6312 farms, often don't use the well-known image file name extensions, which
6313 makes it impossible for <application>Privoxy</application> to guess
6314 the file type just by looking at the URL.
6315 You can use the <literal>+block-as-image</literal> alias defined above for
6317 Note that objects which match this rule but then turn out NOT to be an
6318 image are typically rendered as a <quote>broken image</quote> icon by the
6319 browser. Use cautiously.
6328 ar.atwola.com/</screen>
6332 Now you noticed that the default configuration breaks Forbes Magazine,
6333 but you were too lazy to find out which action is the culprit, and you
6334 were again too lazy to give <link linkend="contact">feedback</link>, so
6335 you just used the <literal>fragile</literal> alias on the site, and
6336 -- <emphasis>whoa!</emphasis> -- it worked. The <literal>fragile</literal>
6337 aliases disables those actions that are most likely to break a site. Also,
6338 good for testing purposes to see if it is <application>Privoxy</application>
6339 that is causing the problem or not. We later find other regular sites
6340 that misbehave, and add those to our personalized list of troublemakers:
6348 .mybank.com</screen>
6352 You like the <quote>fun</quote> text replacements in <filename>default.filter</filename>,
6353 but it is disabled in the distributed actions file.
6354 So you'd like to turn it on in your private,
6355 update-safe config, once and for all:
6360 { +<link linkend="filter-fun">filter{fun}</link> }
6361 / # For ALL sites!</screen>
6365 Note that the above is not really a good idea: There are exceptions
6366 to the filters in <filename>default.action</filename> for things that
6367 really shouldn't be filtered, like code on CVS->Web interfaces. Since
6368 <filename>user.action</filename> has the last word, these exceptions
6369 won't be valid for the <quote>fun</quote> filtering specified here.
6373 You might also worry about how your favourite free websites are
6374 funded, and find that they rely on displaying banner advertisements
6375 to survive. So you might want to specifically allow banners for those
6376 sites that you feel provide value to you:
6388 Note that <literal>allow-ads</literal> has been aliased to
6389 <literal>-<link linkend="block">block</link></literal>,
6390 <literal>-<link linkend="filter-banners-by-size">filter{banners-by-size}</link></literal>, and
6391 <literal>-<link linkend="filter-banners-by-link">filter{banners-by-link}</link></literal> above.
6395 Invoke another alias here to force an over-ride of the MIME type <literal>
6396 application/x-sh</literal> which typically would open a download type
6397 dialog. In my case, I want to look at the shell script, and then I can save
6398 it should I choose to.
6408 <filename>user.action</filename> is generally the best place to define
6409 exceptions and additions to the default policies of
6410 <filename>default.action</filename>. Some actions are safe to have their
6411 default policies set here though. So let's set a default policy to have a
6412 <quote>blank</quote> image as opposed to the checkerboard pattern for
6413 <emphasis>ALL</emphasis> sites. <quote>/</quote> of course matches all URL
6419 { +<link linkend="set-image-blocker">set-image-blocker{blank}</link> }
6420 / # ALL sites</screen>
6426 <!-- ~ End section ~ -->
6430 <!-- ~ End section ~ -->
6432 <!-- ~~~~~~~~ New section Header ~~~~~~~~~ -->
6434 <sect1 id="filter-file">
6435 <title>Filter Files</title>
6438 On-the-fly text substitutions need
6439 to be defined in a <quote>filter file</quote>. Once defined, they
6440 can then be invoked as an <quote>action</quote>.
6444 &my-app; supports three different filter actions:
6445 <literal><link linkend="filter">filter</link></literal> to
6446 rewrite the content that is send to the client,
6447 <literal><link linkend="client-header-filter">client-header-filter</link></literal>
6448 to rewrite headers that are send by the client, and
6449 <literal><link linkend="server-header-filter">server-header-filter</link></literal>
6450 to rewrite headers that are send by the server.
6454 &my-app; also supports two tagger actions:
6455 <literal><link linkend="client-header-tagger">client-header-tagger</link></literal>
6457 <literal><link linkend="server-header-tagger">server-header-tagger</link></literal>.
6458 Taggers and filters use the same syntax in the filter files, the difference
6459 is that taggers don't modify the text they are filtering, but use a rewritten
6460 version of the filtered text as tag. The tags can then be used to change the
6461 applying actions through sections with <link linkend="tag-pattern">tag-patterns</link>.
6466 Multiple filter files can be defined through the <literal> <link
6467 linkend="filterfile">filterfile</link></literal> config directive. The filters
6468 as supplied by the developers are located in
6469 <filename>default.filter</filename>. It is recommended that any locally
6470 defined or modified filters go in a separately defined file such as
6471 <filename>user.filter</filename>.
6475 Common tasks for content filters are to eliminate common annoyances in
6476 HTML and JavaScript, such as pop-up windows,
6477 exit consoles, crippled windows without navigation tools, the
6478 infamous <BLINK> tag etc, to suppress images with certain
6479 width and height attributes (standard banner sizes or web-bugs),
6480 or just to have fun.
6484 Enabled content filters are applied to any content whose
6485 <quote>Content Type</quote> header is recognised as a sign
6486 of text-based content, with the exception of <literal>text/plain</literal>.
6487 Use the <link linkend="FORCE-TEXT-MODE">force-text-mode</link> action
6488 to also filter other content.
6492 Substitutions are made at the source level, so if you want to <quote>roll
6493 your own</quote> filters, you should first be familiar with HTML syntax,
6494 and, of course, regular expressions.
6498 Just like the <link linkend="actions-file">actions files</link>, the
6499 filter file is organized in sections, which are called <emphasis>filters</emphasis>
6500 here. Each filter consists of a heading line, that starts with one of the
6501 <emphasis>keywords</emphasis> <literal>FILTER:</literal>,
6502 <literal>CLIENT-HEADER-FILTER:</literal> or <literal>SERVER-HEADER-FILTER:</literal>
6503 followed by the filter's <emphasis>name</emphasis>, and a short (one line)
6504 <emphasis>description</emphasis> of what it does. Below that line
6505 come the <emphasis>jobs</emphasis>, i.e. lines that define the actual
6506 text substitutions. By convention, the name of a filter
6507 should describe what the filter <emphasis>eliminates</emphasis>. The
6508 comment is used in the <ulink url="http://config.privoxy.org/">web-based
6509 user interface</ulink>.
6513 Once a filter called <replaceable>name</replaceable> has been defined
6514 in the filter file, it can be invoked by using an action of the form
6515 +<literal><link linkend="filter">filter</link>{<replaceable>name</replaceable>}</literal>
6516 in any <link linkend="actions-file">actions file</link>.
6520 Filter definitions start with a header line that contains the filter
6521 type, the filter name and the filter description.
6522 A content filter header line for a filter called <quote>foo</quote> could look
6527 <screen>FILTER: foo Replace all "foo" with "bar"</screen>
6531 Below that line, and up to the next header line, come the jobs that
6532 define what text replacements the filter executes. They are specified
6533 in a syntax that imitates <ulink url="http://www.perl.org/">Perl</ulink>'s
6534 <literal>s///</literal> operator. If you are familiar with Perl, you
6535 will find this to be quite intuitive, and may want to look at the
6536 PCRS documentation for the subtle differences to Perl behaviour. Most
6537 notably, the non-standard option letter <literal>U</literal> is supported,
6538 which turns the default to ungreedy matching.
6543 <ulink url="http://en.wikipedia.org/wiki/Regular_expressions"><quote>Regular
6544 Expressions</quote></ulink>, you might want to take a look at
6545 the <link linkend="regex">Appendix on regular expressions</link>, and
6546 see the <ulink url="http://perldoc.perl.org/perlre.html">Perl
6548 <ulink url="http://perldoc.perl.org/perlop.html">the
6549 <literal>s///</literal> operator's syntax</ulink> and <ulink
6550 url="http://perldoc.perl.org/perlre.html">Perl-style regular
6551 expressions</ulink> in general.
6552 The below examples might also help to get you started.
6556 <!-- ~~~~~~~~ New section Header ~~~~~~~~~ -->
6558 <sect2><title>Filter File Tutorial</title>
6560 Now, let's complete our <quote>foo</quote> content filter. We have already defined
6561 the heading, but the jobs are still missing. Since all it does is to replace
6562 <quote>foo</quote> with <quote>bar</quote>, there is only one (trivial) job
6567 <screen>s/foo/bar/</screen>
6571 But wait! Didn't the comment say that <emphasis>all</emphasis> occurrences
6572 of <quote>foo</quote> should be replaced? Our current job will only take
6573 care of the first <quote>foo</quote> on each page. For global substitution,
6574 we'll need to add the <literal>g</literal> option:
6578 <screen>s/foo/bar/g</screen>
6582 Our complete filter now looks like this:
6585 <screen>FILTER: foo Replace all "foo" with "bar"
6586 s/foo/bar/g</screen>
6590 Let's look at some real filters for more interesting examples. Here you see
6591 a filter that protects against some common annoyances that arise from JavaScript
6592 abuse. Let's look at its jobs one after the other:
6598 FILTER: js-annoyances Get rid of particularly annoying JavaScript abuse
6600 # Get rid of JavaScript referrer tracking. Test page: http://www.randomoddness.com/untitled.htm
6602 s|(<script.*)document\.referrer(.*</script>)|$1"Not Your Business!"$2|Usg</screen>
6606 Following the header line and a comment, you see the job. Note that it uses
6607 <literal>|</literal> as the delimiter instead of <literal>/</literal>, because
6608 the pattern contains a forward slash, which would otherwise have to be escaped
6609 by a backslash (<literal>\</literal>).
6613 Now, let's examine the pattern: it starts with the text <literal><script.*</literal>
6614 enclosed in parentheses. Since the dot matches any character, and <literal>*</literal>
6615 means: <quote>Match an arbitrary number of the element left of myself</quote>, this
6616 matches <quote><script</quote>, followed by <emphasis>any</emphasis> text, i.e.
6617 it matches the whole page, from the start of the first <script> tag.
6621 That's more than we want, but the pattern continues: <literal>document\.referrer</literal>
6622 matches only the exact string <quote>document.referrer</quote>. The dot needed to
6623 be <emphasis>escaped</emphasis>, i.e. preceded by a backslash, to take away its
6624 special meaning as a joker, and make it just a regular dot. So far, the meaning is:
6625 Match from the start of the first <script> tag in a the page, up to, and including,
6626 the text <quote>document.referrer</quote>, if <emphasis>both</emphasis> are present
6627 in the page (and appear in that order).
6631 But there's still more pattern to go. The next element, again enclosed in parentheses,
6632 is <literal>.*</script></literal>. You already know what <literal>.*</literal>
6633 means, so the whole pattern translates to: Match from the start of the first <script>
6634 tag in a page to the end of the last <script> tag, provided that the text
6635 <quote>document.referrer</quote> appears somewhere in between.
6639 This is still not the whole story, since we have ignored the options and the parentheses:
6640 The portions of the page matched by sub-patterns that are enclosed in parentheses, will be
6641 remembered and be available through the variables <literal>$1, $2, ...</literal> in
6642 the substitute. The <literal>U</literal> option switches to ungreedy matching, which means
6643 that the first <literal>.*</literal> in the pattern will only <quote>eat up</quote> all
6644 text in between <quote><script</quote> and the <emphasis>first</emphasis> occurrence
6645 of <quote>document.referrer</quote>, and that the second <literal>.*</literal> will
6646 only span the text up to the <emphasis>first</emphasis> <quote></script></quote>
6647 tag. Furthermore, the <literal>s</literal> option says that the match may span
6648 multiple lines in the page, and the <literal>g</literal> option again means that the
6649 substitution is global.
6653 So, to summarize, the pattern means: Match all scripts that contain the text
6654 <quote>document.referrer</quote>. Remember the parts of the script from
6655 (and including) the start tag up to (and excluding) the string
6656 <quote>document.referrer</quote> as <literal>$1</literal>, and the part following
6657 that string, up to and including the closing tag, as <literal>$2</literal>.
6661 Now the pattern is deciphered, but wasn't this about substituting things? So
6662 lets look at the substitute: <literal>$1"Not Your Business!"$2</literal> is
6663 easy to read: The text remembered as <literal>$1</literal>, followed by
6664 <literal>"Not Your Business!"</literal> (<emphasis>including</emphasis>
6665 the quotation marks!), followed by the text remembered as <literal>$2</literal>.
6666 This produces an exact copy of the original string, with the middle part
6667 (the <quote>document.referrer</quote>) replaced by <literal>"Not Your
6668 Business!"</literal>.
6672 The whole job now reads: Replace <quote>document.referrer</quote> by
6673 <literal>"Not Your Business!"</literal> wherever it appears inside a
6674 <script> tag. Note that this job won't break JavaScript syntax,
6675 since both the original and the replacement are syntactically valid
6676 string objects. The script just won't have access to the referrer
6677 information anymore.
6681 We'll show you two other jobs from the JavaScript taming department, but
6682 this time only point out the constructs of special interest:
6687 # The status bar is for displaying link targets, not pointless blahblah
6689 s/window\.status\s*=\s*(['"]).*?\1/dUmMy=1/ig</screen>
6693 <literal>\s</literal> stands for whitespace characters (space, tab, newline,
6694 carriage return, form feed), so that <literal>\s*</literal> means: <quote>zero
6695 or more whitespace</quote>. The <literal>?</literal> in <literal>.*?</literal>
6696 makes this matching of arbitrary text ungreedy. (Note that the <literal>U</literal>
6697 option is not set). The <literal>['"]</literal> construct means: <quote>a single
6698 <emphasis>or</emphasis> a double quote</quote>. Finally, <literal>\1</literal> is
6699 a back-reference to the first parenthesis just like <literal>$1</literal> above,
6700 with the difference that in the <emphasis>pattern</emphasis>, a backslash indicates
6701 a back-reference, whereas in the <emphasis>substitute</emphasis>, it's the dollar.
6705 So what does this job do? It replaces assignments of single- or double-quoted
6706 strings to the <quote>window.status</quote> object with a dummy assignment
6707 (using a variable name that is hopefully odd enough not to conflict with
6708 real variables in scripts). Thus, it catches many cases where e.g. pointless
6709 descriptions are displayed in the status bar instead of the link target when
6710 you move your mouse over links.
6715 # Kill OnUnload popups. Yummy. Test: http://www.zdnet.com/zdsubs/yahoo/tree/yfs.html
6717 s/(<body [^>]*)onunload(.*>)/$1never$2/iU</screen>
6722 <ulink url="http://www.w3.org/TR/2000/REC-DOM-Level-2-Events-20001113/events.html#Events-eventgroupings-htmlevents">OnUnload
6723 event binding</ulink> in the HTML DOM was a <emphasis>CRIME</emphasis>.
6724 When I close a browser window, I want it to close and die. Basta.
6725 This job replaces the <quote>onunload</quote> attribute in
6726 <quote><body></quote> tags with the dummy word <literal>never</literal>.
6727 Note that the <literal>i</literal> option makes the pattern matching
6728 case-insensitive. Also note that ungreedy matching alone doesn't always guarantee
6729 a minimal match: In the first parenthesis, we had to use <literal>[^>]*</literal>
6730 instead of <literal>.*</literal> to prevent the match from exceeding the
6731 <body> tag if it doesn't contain <quote>OnUnload</quote>, but the page's
6736 The last example is from the fun department:
6741 FILTER: fun Fun text replacements
6743 # Spice the daily news:
6745 s/microsoft(?!\.com)/MicroSuck/ig</screen>
6749 Note the <literal>(?!\.com)</literal> part (a so-called negative lookahead)
6750 in the job's pattern, which means: Don't match, if the string
6751 <quote>.com</quote> appears directly following <quote>microsoft</quote>
6752 in the page. This prevents links to microsoft.com from being trashed, while
6753 still replacing the word everywhere else.
6758 # Buzzword Bingo (example for extended regex syntax)
6760 s* industry[ -]leading \
6762 | customer[ -]focused \
6763 | market[ -]driven \
6764 | award[ -]winning # Comments are OK, too! \
6765 | high[ -]performance \
6766 | solutions[ -]based \
6770 *<font color="red"><b>BINGO!</b></font> \
6775 The <literal>x</literal> option in this job turns on extended syntax, and allows for
6776 e.g. the liberal use of (non-interpreted!) whitespace for nicer formatting.
6784 <!-- ~~~~~~~~ New section Header ~~~~~~~~~ -->
6786 <sect2 id="predefined-filters"><title>The Pre-defined Filters</title>
6790 Note each filter is also listed in the +filter action section above. Please
6791 keep these listings in sync.
6796 The distribution <filename>default.filter</filename> file contains a selection of
6797 pre-defined filters for your convenience:
6802 <term><emphasis>js-annoyances</emphasis></term>
6805 The purpose of this filter is to get rid of particularly annoying JavaScript abuse.
6810 replaces JavaScript references to the browser's referrer information
6811 with the string "Not Your Business!". This compliments the <literal><link
6812 linkend="hide-referrer">hide-referrer</link></literal> action on the content level.
6817 removes the bindings to the DOM's
6818 <ulink url="http://www.w3.org/TR/2000/REC-DOM-Level-2-Events-20001113/events.html#Events-eventgroupings-htmlevents">unload
6819 event</ulink> which we feel has no right to exist and is responsible for most <quote>exit consoles</quote>, i.e.
6820 nasty windows that pop up when you close another one.
6825 removes code that causes new windows to be opened with undesired properties, such as being
6826 full-screen, non-resizeable, without location, status or menu bar etc.
6832 Use with caution. This is an aggressive filter, and can break sites that
6833 rely heavily on JavaScript.
6839 <term><emphasis>js-events</emphasis></term>
6842 This is a very radical measure. It removes virtually all JavaScript event bindings, which
6843 means that scripts can not react to user actions such as mouse movements or clicks, window
6844 resizing etc, anymore. Use with caution!
6847 We <emphasis>strongly discourage</emphasis> using this filter as a default since it breaks
6848 many legitimate scripts. It is meant for use only on extra-nasty sites (should you really
6855 <term><emphasis>html-annoyances</emphasis></term>
6858 This filter will undo many common instances of HTML based abuse.
6861 The <literal>BLINK</literal> and <literal>MARQUEE</literal> tags
6862 are neutralized (yeah baby!), and browser windows will be created as
6863 resizeable (as of course they should be!), and will have location,
6864 scroll and menu bars -- even if specified otherwise.
6870 <term><emphasis>content-cookies</emphasis></term>
6873 Most cookies are set in the HTTP dialog, where they can be intercepted
6875 <literal><link linkend="crunch-incoming-cookies">crunch-incoming-cookies</link></literal>
6876 and <literal><link linkend="crunch-outgoing-cookies">crunch-outgoing-cookies</link></literal>
6877 actions. But web sites increasingly make use of HTML meta tags and JavaScript
6878 to sneak cookies to the browser on the content level.
6881 This filter disables most HTML and JavaScript code that reads or sets
6882 cookies. It cannot detect all clever uses of these types of code, so it
6883 should not be relied on as an absolute fix. Use it wherever you would also
6884 use the cookie crunch actions.
6890 <term><emphasis>refresh-tags</emphasis></term>
6893 Disable any refresh tags if the interval is greater than nine seconds (so
6894 that redirections done via refresh tags are not destroyed). This is useful
6895 for dial-on-demand setups, or for those who find this HTML feature
6902 <term><emphasis>unsolicited-popups</emphasis></term>
6905 This filter attempts to prevent only <quote>unsolicited</quote> pop-up
6906 windows from opening, yet still allow pop-up windows that the user
6907 has explicitly chosen to open. It was added in version 3.0.1,
6908 as an improvement over earlier such filters.
6911 Technical note: The filter works by redefining the window.open JavaScript
6912 function to a dummy function, <literal>PrivoxyWindowOpen()</literal>,
6913 during the loading and rendering phase of each HTML page access, and
6914 restoring the function afterward.
6917 This is recommended only for browsers that cannot perform this function
6918 reliably themselves. And be aware that some sites require such windows
6919 in order to function normally. Use with caution.
6925 <term><emphasis>all-popups</emphasis></term>
6928 Attempt to prevent <emphasis>all</emphasis> pop-up windows from opening.
6929 Note this should be used with even more discretion than the above, since
6930 it is more likely to break some sites that require pop-ups for normal
6931 usage. Use with caution.
6937 <term><emphasis>img-reorder</emphasis></term>
6940 This is a helper filter that has no value if used alone. It makes the
6941 <literal>banners-by-size</literal> and <literal>banners-by-link</literal>
6942 (see below) filters more effective and should be enabled together with them.
6948 <term><emphasis>banners-by-size</emphasis></term>
6951 This filter removes image tags purely based on what size they are. Fortunately
6952 for us, many ads and banner images tend to conform to certain standardized
6953 sizes, which makes this filter quite effective for ad stripping purposes.
6956 Occasionally this filter will cause false positives on images that are not ads,
6957 but just happen to be of one of the standard banner sizes.
6960 Recommended only for those who require extreme ad blocking. The default
6961 block rules should catch 95+% of all ads <emphasis>without</emphasis> this filter enabled.
6967 <term><emphasis>banners-by-link</emphasis></term>
6970 This is an experimental filter that attempts to kill any banners if
6971 their URLs seem to point to known or suspected click trackers. It is currently
6972 not of much value and is not recommended for use by default.
6978 <term><emphasis>webbugs</emphasis></term>
6981 Webbugs are small, invisible images (technically 1X1 GIF images), that
6982 are used to track users across websites, and collect information on them.
6983 As an HTML page is loaded by the browser, an embedded image tag causes the
6984 browser to contact a third-party site, disclosing the tracking information
6985 through the requested URL and/or cookies for that third-party domain, without
6986 the user ever becoming aware of the interaction with the third-party site.
6987 HTML-ized spam also uses a similar technique to verify email addresses.
6990 This filter removes the HTML code that loads such <quote>webbugs</quote>.
6996 <term><emphasis>tiny-textforms</emphasis></term>
6999 A rather special-purpose filter that can be used to enlarge textareas (those
7000 multi-line text boxes in web forms) and turn off hard word wrap in them.
7001 It was written for the sourceforge.net tracker system where such boxes are
7002 a nuisance, but it can be handy on other sites, too.
7005 It is not recommended to use this filter as a default.
7011 <term><emphasis>jumping-windows</emphasis></term>
7014 Many consider windows that move, or resize themselves to be abusive. This filter
7015 neutralizes the related JavaScript code. Note that some sites might not display
7016 or behave as intended when using this filter. Use with caution.
7022 <term><emphasis>frameset-borders</emphasis></term>
7025 Some web designers seem to assume that everyone in the world will view their
7026 web sites using the same browser brand and version, screen resolution etc,
7027 because only that assumption could explain why they'd use static frame sizes,
7028 yet prevent their frames from being resized by the user, should they be too
7029 small to show their whole content.
7032 This filter removes the related HTML code. It should only be applied to sites
7039 <term><emphasis>demoronizer</emphasis></term>
7042 Many Microsoft products that generate HTML use non-standard extensions (read:
7043 violations) of the ISO 8859-1 aka Latin-1 character set. This can cause those
7044 HTML documents to display with errors on standard-compliant platforms.
7047 This filter translates the MS-only characters into Latin-1 equivalents.
7048 It is not necessary when using MS products, and will cause corruption of
7049 all documents that use 8-bit character sets other than Latin-1. It's mostly
7050 worthwhile for Europeans on non-MS platforms, if weird garbage characters
7051 sometimes appear on some pages, or user agents that don't correct for this on
7054 My version of Mozilla (ancient) shows litte square boxes for quote
7055 characters, and apostrophes on moronized pages. So many pages have this, I
7056 can read them fine now. HB 08/27/06
7063 <term><emphasis>shockwave-flash</emphasis></term>
7066 A filter for shockwave haters. As the name suggests, this filter strips code
7067 out of web pages that is used to embed shockwave flash objects.
7075 <term><emphasis>quicktime-kioskmode</emphasis></term>
7078 Change HTML code that embeds Quicktime objects so that kioskmode, which
7079 prevents saving, is disabled.
7085 <term><emphasis>fun</emphasis></term>
7088 Text replacements for subversive browsing fun. Make fun of your favorite
7089 Monopolist or play buzzword bingo.
7095 <term><emphasis>crude-parental</emphasis></term>
7098 A demonstration-only filter that shows how <application>Privoxy</application>
7099 can be used to delete web content on a keyword basis.
7105 <term><emphasis>ie-exploits</emphasis></term>
7108 An experimental collection of text replacements to disable malicious HTML and JavaScript
7109 code that exploits known security holes in Internet Explorer.
7112 Presently, it only protects against Nimda and a cross-site scripting bug, and
7113 would need active maintenance to provide more substantial protection.
7119 <term><emphasis>site-specifics</emphasis></term>
7122 Some web sites have very specific problems, the cure for which doesn't apply
7123 anywhere else, or could even cause damage on other sites.
7126 This is a collection of such site-specific cures which should only be applied
7127 to the sites they were intended for, which is what the supplied
7128 <filename>default.action</filename> file does. Users shouldn't need to change
7129 anything regarding this filter.
7135 <term><emphasis>google</emphasis></term>
7138 A CSS based block for Google text ads. Also removes a width limitation
7139 and the toolbar advertisement.
7145 <term><emphasis>yahoo</emphasis></term>
7148 Another CSS based block, this time for Yahoo text ads. And removes
7149 a width limitation as well.
7155 <term><emphasis>msn</emphasis></term>
7158 Another CSS based block, this time for MSN text ads. And removes
7159 tracking URLs, as well as a width limitation.
7165 <term><emphasis>blogspot</emphasis></term>
7168 Cleans up some Blogspot blogs. Read the fine print before using this one!
7171 This filter also intentionally removes some navigation stuff and sets the
7172 page width to 100%. As a result, some rounded <quote>corners</quote> would
7173 appear to early or not at all and as fixing this would require a browser
7174 that understands background-size (CSS3), they are removed instead.
7180 <term><emphasis>xml-to-html</emphasis></term>
7183 Server-header filter to change the Content-Type from xml to html.
7189 <term><emphasis>html-to-xml</emphasis></term>
7192 Server-header filter to change the Content-Type from html to xml.
7198 <term><emphasis>no-ping</emphasis></term>
7201 Removes the non-standard <literal>ping</literal> attribute from
7202 anchor and area HTML tags.
7208 <term><emphasis>hide-tor-exit-notation</emphasis></term>
7211 Client-header filter to remove the <command>Tor</command> exit node notation
7212 found in Host and Referer headers.
7215 If &my-app; and <command>Tor</command> are chained and &my-app;
7216 is configured to use socks4a, one can use <quote>http://www.example.org.foobar.exit/</quote>
7217 to access the host <quote>www.example.org</quote> through the
7218 <command>Tor</command> exit node <quote>foobar</quote>.
7221 As the HTTP client isn't aware of this notation, it treats the
7222 whole string <quote>www.example.org.foobar.exit</quote> as host and uses it
7223 for the <quote>Host</quote> and <quote>Referer</quote> headers. From the
7224 server's point of view the resulting headers are invalid and can cause problems.
7227 An invalid <quote>Referer</quote> header can trigger <quote>hot-linking</quote>
7228 protections, an invalid <quote>Host</quote> header will make it impossible for
7229 the server to find the right vhost (several domains hosted on the same IP address).
7232 This client-header filter removes the <quote>foo.exit</quote> part in those headers
7233 to prevent the mentioned problems. Note that it only modifies
7234 the HTTP headers, it doesn't make it impossible for the server
7235 to detect your <command>Tor</command> exit node based on the IP address
7236 the request is coming from.
7243 <term><emphasis> </emphasis></term>
7257 <!-- ~ End section ~ -->
7261 <!-- ~~~~~ New section ~~~~~ -->
7263 <sect1 id="templates">
7264 <title>Privoxy's Template Files</title>
7266 All <application>Privoxy</application> built-in pages, i.e. error pages such as the
7267 <ulink url="http://show-the-404-error.page"><quote>404 - No Such Domain</quote>
7268 error page</ulink>, the <ulink
7269 url="http://ads.bannerserver.example.com/nasty-ads/sponsor.html"><quote>BLOCKED</quote>
7271 and all pages of its <ulink url="http://config.privoxy.org/">web-based
7272 user interface</ulink>, are generated from <emphasis>templates</emphasis>.
7273 (<application>Privoxy</application> must be running for the above links to work as
7278 These templates are stored in a subdirectory of the <link linkend="confdir">configuration
7279 directory</link> called <filename>templates</filename>. On Unixish platforms,
7281 <ulink url="file:///etc/privoxy/templates/"><filename>/etc/privoxy/templates/</filename></ulink>.
7285 The templates are basically normal HTML files, but with place-holders (called symbols
7286 or exports), which <application>Privoxy</application> fills at run time. It
7287 is possible to edit the templates with a normal text editor, should you want
7288 to customize them. (<emphasis>Not recommended for the casual
7289 user</emphasis>). Should you create your own custom templates, you should use
7290 the <filename>config</filename> setting <link linkend="templdir">templdir</link>
7291 to specify an alternate location, so your templates do not get overwritten
7295 Note that just like in configuration files, lines starting
7296 with <literal>#</literal> are ignored when the templates are filled in.
7300 The place-holders are of the form <literal>@name@</literal>, and you will
7301 find a list of available symbols, which vary from template to template,
7302 in the comments at the start of each file. Note that these comments are not
7303 always accurate, and that it's probably best to look at the existing HTML
7304 code to find out which symbols are supported and what they are filled in with.
7308 A special application of this substitution mechanism is to make whole
7309 blocks of HTML code disappear when a specific symbol is set. We use this
7310 for many purposes, one of them being to include the beta warning in all
7311 our user interface (CGI) pages when <application>Privoxy</application>
7312 is in an alpha or beta development stage:
7317 <!-- @if-unstable-start -->
7319 ... beta warning HTML code goes here ...
7321 <!-- if-unstable-end@ --></screen>
7325 If the "unstable" symbol is set, everything in between and including
7326 <literal>@if-unstable-start</literal> and <literal>if-unstable-end@</literal>
7327 will disappear, leaving nothing but an empty comment:
7331 <screen><!-- --></screen>
7335 There's also an if-then-else construct and an <literal>#include</literal>
7336 mechanism, but you'll sure find out if you are inclined to edit the
7341 All templates refer to a style located at
7342 <ulink url="http://config.privoxy.org/send-stylesheet"><literal>http://config.privoxy.org/send-stylesheet</literal></ulink>.
7343 This is, of course, locally served by <application>Privoxy</application>
7344 and the source for it can be found and edited in the
7345 <filename>cgi-style.css</filename> template.
7350 <!-- ~ End section ~ -->
7354 <!-- ~~~~~ New section ~~~~~ -->
7356 <sect1 id="contact"><title>Contacting the Developers, Bug Reporting and Feature
7359 <!-- Include contacting.sgml boilerplate: -->
7361 <!-- end boilerplate -->
7365 <!-- ~ End section ~ -->
7368 <!-- ~~~~~ New section ~~~~~ -->
7369 <sect1 id="copyright"><title>Privoxy Copyright, License and History</title>
7371 <!-- Include copyright.sgml: -->
7373 <!-- end copyright -->
7376 <application>Privoxy</application> is free software; you can
7377 redistribute it and/or modify it under the terms of the
7378 <citetitle>GNU General Public License</citetitle>, version 2,
7379 as published by the Free Software Foundation and included in
7383 <!-- ~~~~~ New section ~~~~~ -->
7384 <sect2 id="license"><title>License</title>
7386 <screen><![ RCDATA [ &GPLv2; ]]></screen>
7390 <!-- ~ End section ~ -->
7393 <!-- ~~~~~ New section ~~~~~ -->
7395 <sect2 id="history"><title>History</title>
7396 <!-- Include history.sgml: -->
7398 <!-- end history -->
7401 <sect2 id="authors"><title>Authors</title>
7402 <!-- Include p-authors.sgml: -->
7404 <!-- end authors -->
7409 <!-- ~ End section ~ -->
7412 <!-- ~~~~~ New section ~~~~~ -->
7413 <sect1 id="seealso"><title>See Also</title>
7414 <!-- Include seealso.sgml: -->
7416 <!-- end seealso -->
7421 <!-- ~~~~~ New section ~~~~~ -->
7422 <sect1 id="appendix"><title>Appendix</title>
7425 <!-- ~~~~~ New section ~~~~~ -->
7427 <title>Regular Expressions</title>
7429 <application>Privoxy</application> uses Perl-style <quote>regular
7430 expressions</quote> in its <link linkend="actions-file">actions
7431 files</link> and <link linkend="filter-file">filter file</link>,
7432 through the <ulink url="http://www.pcre.org/">PCRE</ulink> and
7435 <ulink url="http://www.oesterhelt.org/pcrs/">PCRS</ulink> libraries.
7437 <application>PCRS</application> libraries.
7441 If you are reading this, you probably don't understand what <quote>regular
7442 expressions</quote> are, or what they can do. So this will be a very brief
7443 introduction only. A full explanation would require a <ulink
7444 url="http://www.oreilly.com/catalog/regex/">book</ulink> ;-)
7448 Regular expressions provide a language to describe patterns that can be
7449 run against strings of characters (letter, numbers, etc), to see if they
7450 match the string or not. The patterns are themselves (sometimes complex)
7451 strings of literal characters, combined with wild-cards, and other special
7452 characters, called meta-characters. The <quote>meta-characters</quote> have
7453 special meanings and are used to build complex patterns to be matched against.
7454 Perl Compatible Regular Expressions are an especially convenient
7455 <quote>dialect</quote> of the regular expression language.
7459 To make a simple analogy, we do something similar when we use wild-card
7460 characters when listing files with the <command>dir</command> command in DOS.
7461 <literal>*.*</literal> matches all filenames. The <quote>special</quote>
7462 character here is the asterisk which matches any and all characters. We can be
7463 more specific and use <literal>?</literal> to match just individual
7464 characters. So <quote>dir file?.text</quote> would match
7465 <quote>file1.txt</quote>, <quote>file2.txt</quote>, etc. We are pattern
7466 matching, using a similar technique to <quote>regular expressions</quote>!
7470 Regular expressions do essentially the same thing, but are much, much more
7471 powerful. There are many more <quote>special characters</quote> and ways of
7472 building complex patterns however. Let's look at a few of the common ones,
7473 and then some examples:
7478 <emphasis>.</emphasis> - Matches any single character, e.g. <quote>a</quote>,
7479 <quote>A</quote>, <quote>4</quote>, <quote>:</quote>, or <quote>@</quote>.
7481 </simplelist></para>
7485 <emphasis>?</emphasis> - The preceding character or expression is matched ZERO or ONE
7488 </simplelist></para>
7492 <emphasis>+</emphasis> - The preceding character or expression is matched ONE or MORE
7495 </simplelist></para>
7499 <emphasis>*</emphasis> - The preceding character or expression is matched ZERO or MORE
7502 </simplelist></para>
7506 <emphasis>\</emphasis> - The <quote>escape</quote> character denotes that
7507 the following character should be taken literally. This is used where one of the
7508 special characters (e.g. <quote>.</quote>) needs to be taken literally and
7509 not as a special meta-character. Example: <quote>example\.com</quote>, makes
7510 sure the period is recognized only as a period (and not expanded to its
7511 meta-character meaning of any single character).
7513 </simplelist></para>
7517 <emphasis>[ ]</emphasis> - Characters enclosed in brackets will be matched if
7518 any of the enclosed characters are encountered. For instance, <quote>[0-9]</quote>
7519 matches any numeric digit (zero through nine). As an example, we can combine
7520 this with <quote>+</quote> to match any digit one of more times: <quote>[0-9]+</quote>.
7522 </simplelist></para>
7526 <emphasis>( )</emphasis> - parentheses are used to group a sub-expression,
7527 or multiple sub-expressions.
7529 </simplelist></para>
7533 <emphasis>|</emphasis> - The <quote>bar</quote> character works like an
7534 <quote>or</quote> conditional statement. A match is successful if the
7535 sub-expression on either side of <quote>|</quote> matches. As an example:
7536 <quote>/(this|that) example/</quote> uses grouping and the bar character
7537 and would match either <quote>this example</quote> or <quote>that
7538 example</quote>, and nothing else.
7540 </simplelist></para>
7543 These are just some of the ones you are likely to use when matching URLs with
7544 <application>Privoxy</application>, and is a long way from a definitive
7545 list. This is enough to get us started with a few simple examples which may
7546 be more illuminating:
7550 <emphasis><literal>/.*/banners/.*</literal></emphasis> - A simple example
7551 that uses the common combination of <quote>.</quote> and <quote>*</quote> to
7552 denote any character, zero or more times. In other words, any string at all.
7553 So we start with a literal forward slash, then our regular expression pattern
7554 (<quote>.*</quote>) another literal forward slash, the string
7555 <quote>banners</quote>, another forward slash, and lastly another
7556 <quote>.*</quote>. We are building
7557 a directory path here. This will match any file with the path that has a
7558 directory named <quote>banners</quote> in it. The <quote>.*</quote> matches
7559 any characters, and this could conceivably be more forward slashes, so it
7560 might expand into a much longer looking path. For example, this could match:
7561 <quote>/eye/hate/spammers/banners/annoy_me_please.gif</quote>, or just
7562 <quote>/banners/annoying.html</quote>, or almost an infinite number of other
7563 possible combinations, just so it has <quote>banners</quote> in the path
7568 And now something a little more complex:
7572 <emphasis><literal>/.*/adv((er)?ts?|ertis(ing|ements?))?/</literal></emphasis> -
7573 We have several literal forward slashes again (<quote>/</quote>), so we are
7574 building another expression that is a file path statement. We have another
7575 <quote>.*</quote>, so we are matching against any conceivable sub-path, just so
7576 it matches our expression. The only true literal that <emphasis>must
7577 match</emphasis> our pattern is <application>adv</application>, together with
7578 the forward slashes. What comes after the <quote>adv</quote> string is the
7583 Remember the <quote>?</quote> means the preceding expression (either a
7584 literal character or anything grouped with <quote>(...)</quote> in this case)
7585 can exist or not, since this means either zero or one match. So
7586 <quote>((er)?ts?|ertis(ing|ements?))</quote> is optional, as are the
7587 individual sub-expressions: <quote>(er)</quote>,
7588 <quote>(ing|ements?)</quote>, and the <quote>s</quote>. The <quote>|</quote>
7589 means <quote>or</quote>. We have two of those. For instance,
7590 <quote>(ing|ements?)</quote>, can expand to match either <quote>ing</quote>
7591 <emphasis>OR</emphasis> <quote>ements?</quote>. What is being done here, is an
7592 attempt at matching as many variations of <quote>advertisement</quote>, and
7593 similar, as possible. So this would expand to match just <quote>adv</quote>,
7594 or <quote>advert</quote>, or <quote>adverts</quote>, or
7595 <quote>advertising</quote>, or <quote>advertisement</quote>, or
7596 <quote>advertisements</quote>. You get the idea. But it would not match
7597 <quote>advertizements</quote> (with a <quote>z</quote>). We could fix that by
7598 changing our regular expression to:
7599 <quote>/.*/adv((er)?ts?|erti(s|z)(ing|ements?))?/</quote>, which would then match
7604 <emphasis><literal>/.*/advert[0-9]+\.(gif|jpe?g)</literal></emphasis> - Again
7605 another path statement with forward slashes. Anything in the square brackets
7606 <quote>[ ]</quote> can be matched. This is using <quote>0-9</quote> as a
7607 shorthand expression to mean any digit one through nine. It is the same as
7608 saying <quote>0123456789</quote>. So any digit matches. The <quote>+</quote>
7609 means one or more of the preceding expression must be included. The preceding
7610 expression here is what is in the square brackets -- in this case, any digit
7611 one through nine. Then, at the end, we have a grouping: <quote>(gif|jpe?g)</quote>.
7612 This includes a <quote>|</quote>, so this needs to match the expression on
7613 either side of that bar character also. A simple <quote>gif</quote> on one side, and the other
7614 side will in turn match either <quote>jpeg</quote> or <quote>jpg</quote>,
7615 since the <quote>?</quote> means the letter <quote>e</quote> is optional and
7616 can be matched once or not at all. So we are building an expression here to
7617 match image GIF or JPEG type image file. It must include the literal
7618 string <quote>advert</quote>, then one or more digits, and a <quote>.</quote>
7619 (which is now a literal, and not a special character, since it is escaped
7620 with <quote>\</quote>), and lastly either <quote>gif</quote>, or
7621 <quote>jpeg</quote>, or <quote>jpg</quote>. Some possible matches would
7622 include: <quote>//advert1.jpg</quote>,
7623 <quote>/nasty/ads/advert1234.gif</quote>,
7624 <quote>/banners/from/hell/advert99.jpg</quote>. It would not match
7625 <quote>advert1.gif</quote> (no leading slash), or
7626 <quote>/adverts232.jpg</quote> (the expression does not include an
7627 <quote>s</quote>), or <quote>/advert1.jsp</quote> (<quote>jsp</quote> is not
7628 in the expression anywhere).
7632 We are barely scratching the surface of regular expressions here so that you
7633 can understand the default <application>Privoxy</application>
7634 configuration files, and maybe use this knowledge to customize your own
7635 installation. There is much, much more that can be done with regular
7636 expressions. Now that you know enough to get started, you can learn more on
7641 More reading on Perl Compatible Regular expressions:
7642 <ulink url="http://perldoc.perl.org/perlre.html">http://perldoc.perl.org/perlre.html</ulink>
7646 For information on regular expression based substitutions and their applications
7647 in filters, please see the <link linkend="filter-file">filter file tutorial</link>
7652 <!-- ~ End section ~ -->
7655 <!-- ~~~~~ New section ~~~~~ -->
7657 <title>Privoxy's Internal Pages</title>
7660 Since <application>Privoxy</application> proxies each requested
7661 web page, it is easy for <application>Privoxy</application> to
7662 trap certain special URLs. In this way, we can talk directly to
7663 <application>Privoxy</application>, and see how it is
7664 configured, see how our rules are being applied, change these
7665 rules and other configuration options, and even turn
7666 <application>Privoxy's</application> filtering off, all with
7672 The URLs listed below are the special ones that allow direct access
7673 to <application>Privoxy</application>. Of course,
7674 <application>Privoxy</application> must be running to access these. If
7675 not, you will get a friendly error message. Internet access is not
7688 <ulink url="http://config.privoxy.org/">http://config.privoxy.org/</ulink>
7692 There is a shortcut: <ulink url="http://p.p/">http://p.p/</ulink> (But it
7693 doesn't provide a fall-back to a real page, in case the request is not
7694 sent through <application>Privoxy</application>)
7700 Show information about the current configuration, including viewing and
7701 editing of actions files:
7705 <ulink url="http://config.privoxy.org/show-status">http://config.privoxy.org/show-status</ulink>
7712 Show the source code version numbers:
7716 <ulink url="http://config.privoxy.org/show-version">http://config.privoxy.org/show-version</ulink>
7723 Show the browser's request headers:
7727 <ulink url="http://config.privoxy.org/show-request">http://config.privoxy.org/show-request</ulink>
7734 Show which actions apply to a URL and why:
7738 <ulink url="http://config.privoxy.org/show-url-info">http://config.privoxy.org/show-url-info</ulink>
7745 Toggle Privoxy on or off. This feature can be turned off/on in the main
7746 <filename>config</filename> file. When toggled <quote>off</quote>, <quote>Privoxy</quote>
7747 continues to run, but only as a pass-through proxy, with no actions taking
7752 <ulink url="http://config.privoxy.org/toggle">http://config.privoxy.org/toggle</ulink>
7756 Short cuts. Turn off, then on:
7760 <ulink url="http://config.privoxy.org/toggle?set=disable">http://config.privoxy.org/toggle?set=disable</ulink>
7765 <ulink url="http://config.privoxy.org/toggle?set=enable">http://config.privoxy.org/toggle?set=enable</ulink>
7774 These may be bookmarked for quick reference. See next.
7778 <sect3 id="bookmarklets">
7779 <title>Bookmarklets</title>
7781 Below are some <quote>bookmarklets</quote> to allow you to easily access a
7782 <quote>mini</quote> version of some of <application>Privoxy's</application>
7783 special pages. They are designed for MS Internet Explorer, but should work
7784 equally well in Netscape, Mozilla, and other browsers which support
7785 JavaScript. They are designed to run directly from your bookmarks - not by
7786 clicking the links below (although that should work for testing).
7789 To save them, right-click the link and choose <quote>Add to Favorites</quote>
7790 (IE) or <quote>Add Bookmark</quote> (Netscape). You will get a warning that
7791 the bookmark <quote>may not be safe</quote> - just click OK. Then you can run the
7792 Bookmarklet directly from your favorites/bookmarks. For even faster access,
7793 you can put them on the <quote>Links</quote> bar (IE) or the <quote>Personal
7794 Toolbar</quote> (Netscape), and run them with a single click.
7803 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>
7810 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>
7817 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)
7824 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>
7830 <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>
7836 <ulink url="javascript:void(window.open('http://config.privoxy.org/show-url-info?url='+escape(location.href),'Why').focus());">Privoxy - Why?</ulink>
7843 Credit: The site which gave us the general idea for these bookmarklets is
7844 <ulink url="http://www.bookmarklets.com/">www.bookmarklets.com</ulink>. They
7845 have more information about bookmarklets.
7854 <!-- ~~~~~ New section ~~~~~ -->
7856 <title>Chain of Events</title>
7858 Let's take a quick look at how some of <application>Privoxy's</application>
7859 core features are triggered, and the ensuing sequence of events when a web
7860 page is requested by your browser:
7867 First, your web browser requests a web page. The browser knows to send
7868 the request to <application>Privoxy</application>, which will in turn,
7869 relay the request to the remote web server after passing the following
7875 <application>Privoxy</application> traps any request for its own internal CGI
7876 pages (e.g <ulink url="http://p.p/">http://p.p/</ulink>) and sends the CGI page back to the browser.
7881 Next, <application>Privoxy</application> checks to see if the URL
7883 linkend="BLOCK"><quote>+block</quote></link> patterns. If
7884 so, the URL is then blocked, and the remote web server will not be contacted.
7885 <link linkend="HANDLE-AS-IMAGE"><quote>+handle-as-image</quote></link>
7887 <link linkend="HANDLE-AS-EMPTY-DOCUMENT"><quote>+handle-as-empty-document</quote></link>
7888 are then checked, and if there is no match, an
7889 HTML <quote>BLOCKED</quote> page is sent back to the browser. Otherwise, if
7890 it does match, an image is returned for the former, and an empty text
7891 document for the latter. The type of image would depend on the setting of
7892 <link linkend="SET-IMAGE-BLOCKER"><quote>+set-image-blocker</quote></link>
7893 (blank, checkerboard pattern, or an HTTP redirect to an image elsewhere).
7898 Untrusted URLs are blocked. If URLs are being added to the
7899 <filename>trust</filename> file, then that is done.
7904 If the URL pattern matches the <link
7905 linkend="FAST-REDIRECTS"><quote>+fast-redirects</quote></link> action,
7906 it is then processed. Unwanted parts of the requested URL are stripped.
7911 Now the rest of the client browser's request headers are processed. If any
7912 of these match any of the relevant actions (e.g. <link
7913 linkend="HIDE-USER-AGENT"><quote>+hide-user-agent</quote></link>,
7914 etc.), headers are suppressed or forged as determined by these actions and
7920 Now the web server starts sending its response back (i.e. typically a web
7926 First, the server headers are read and processed to determine, among other
7927 things, the MIME type (document type) and encoding. The headers are then
7928 filtered as determined by the
7929 <link linkend="CRUNCH-INCOMING-COOKIES"><quote>+crunch-incoming-cookies</quote></link>,
7930 <link linkend="SESSION-COOKIES-ONLY"><quote>+session-cookies-only</quote></link>,
7931 and <link linkend="DOWNGRADE-HTTP-VERSION"><quote>+downgrade-http-version</quote></link>
7937 If any <link linkend="FILTER"><quote>+filter</quote></link> action
7939 linkend="DEANIMATE-GIFS"><quote>+deanimate-gifs</quote></link>
7940 action applies (and the document type fits the action), the rest of the page is
7941 read into memory (up to a configurable limit). Then the filter rules (from
7942 <filename>default.filter</filename> and any other filter files) are
7943 processed against the buffered content. Filters are applied in the order
7944 they are specified in one of the filter files. Animated GIFs, if present,
7945 are reduced to either the first or last frame, depending on the action
7946 setting.The entire page, which is now filtered, is then sent by
7947 <application>Privoxy</application> back to your browser.
7950 If neither a <link linkend="FILTER"><quote>+filter</quote></link> action
7952 linkend="DEANIMATE-GIFS"><quote>+deanimate-gifs</quote></link>
7953 matches, then <application>Privoxy</application> passes the raw data through
7954 to the client browser as it becomes available.
7959 As the browser receives the now (possibly filtered) page content, it
7960 reads and then requests any URLs that may be embedded within the page
7961 source, e.g. ad images, stylesheets, JavaScript, other HTML documents (e.g.
7962 frames), sounds, etc. For each of these objects, the browser issues a
7963 separate request (this is easily viewable in <application>Privoxy's</application>
7964 logs). And each such request is in turn processed just as above. Note that a
7965 complex web page will have many, many such embedded URLs. If these
7966 secondary requests are to a different server, then quite possibly a very
7967 differing set of actions is triggered.
7974 NOTE: This is somewhat of a simplistic overview of what happens with each URL
7975 request. For the sake of brevity and simplicity, we have focused on
7976 <application>Privoxy's</application> core features only.
7982 <!-- ~~~~~ New section ~~~~~ -->
7983 <sect2 id="actionsanat">
7984 <title>Troubleshooting: Anatomy of an Action</title>
7987 The way <application>Privoxy</application> applies
7988 <link linkend="ACTIONS">actions</link> and <link linkend="FILTER">filters</link>
7989 to any given URL can be complex, and not always so
7990 easy to understand what is happening. And sometimes we need to be able to
7991 <emphasis>see</emphasis> just what <application>Privoxy</application> is
7992 doing. Especially, if something <application>Privoxy</application> is doing
7993 is causing us a problem inadvertently. It can be a little daunting to look at
7994 the actions and filters files themselves, since they tend to be filled with
7995 <link linkend="regex">regular expressions</link> whose consequences are not
8000 One quick test to see if <application>Privoxy</application> is causing a problem
8001 or not, is to disable it temporarily. This should be the first troubleshooting
8002 step. See <link linkend="bookmarklets">the Bookmarklets</link> section on a quick
8003 and easy way to do this (be sure to flush caches afterward!). Looking at the
8004 logs is a good idea too. (Note that both the toggle feature and logging are
8005 enabled via <filename>config</filename> file settings, and may need to be
8006 turned <quote>on</quote>.)
8009 Another easy troubleshooting step to try is if you have done any
8010 customization of your installation, revert back to the installed
8011 defaults and see if that helps. There are times the developers get complaints
8012 about one thing or another, and the problem is more related to a customized
8013 configuration issue.
8017 <application>Privoxy</application> also provides the
8018 <ulink url="http://config.privoxy.org/show-url-info">http://config.privoxy.org/show-url-info</ulink>
8019 page that can show us very specifically how <application>actions</application>
8020 are being applied to any given URL. This is a big help for troubleshooting.
8024 First, enter one URL (or partial URL) at the prompt, and then
8025 <application>Privoxy</application> will tell us
8026 how the current configuration will handle it. This will not
8027 help with filtering effects (i.e. the <link
8028 linkend="FILTER"><quote>+filter</quote></link> action) from
8029 one of the filter files since this is handled very
8030 differently and not so easy to trap! It also will not tell you about any other
8031 URLs that may be embedded within the URL you are testing. For instance, images
8032 such as ads are expressed as URLs within the raw page source of HTML pages. So
8033 you will only get info for the actual URL that is pasted into the prompt area
8034 -- not any sub-URLs. If you want to know about embedded URLs like ads, you
8035 will have to dig those out of the HTML source. Use your browser's <quote>View
8036 Page Source</quote> option for this. Or right click on the ad, and grab the
8041 Let's try an example, <ulink url="http://google.com">google.com</ulink>,
8042 and look at it one section at a time in a sample configuration (your real
8043 configuration may vary):
8048 Matches for http://www.google.com:
8050 In file: default.action <guibutton>[ View ]</guibutton> <guibutton>[ Edit ]</guibutton>
8052 {+change-x-forwarded-for{block}
8053 +deanimate-gifs {last}
8054 +fast-redirects {check-decoded-url}
8055 +filter {refresh-tags}
8056 +filter {img-reorder}
8057 +filter {banners-by-size}
8059 +filter {jumping-windows}
8060 +filter {ie-exploits}
8061 +hide-from-header {block}
8062 +hide-referrer {forge}
8063 +session-cookies-only
8064 +set-image-blocker {pattern}
8067 { -session-cookies-only }
8073 In file: user.action <guibutton>[ View ]</guibutton> <guibutton>[ Edit ]</guibutton>
8074 (no matches in this file)
8079 This is telling us how we have defined our
8080 <link linkend="ACTIONS"><quote>actions</quote></link>, and
8081 which ones match for our test case, <quote>google.com</quote>.
8082 Displayed is all the actions that are available to us. Remember,
8083 the <literal>+</literal> sign denotes <quote>on</quote>. <literal>-</literal>
8084 denotes <quote>off</quote>. So some are <quote>on</quote> here, but many
8085 are <quote>off</quote>. Each example we try may provide a slightly different
8086 end result, depending on our configuration directives.
8090 is for our <filename>default.action</filename> file. The large, multi-line
8091 listing, is how the actions are set to match for all URLs, i.e. our default
8092 settings. If you look at your <quote>actions</quote> file, this would be the
8093 section just below the <quote>aliases</quote> section near the top. This
8094 will apply to all URLs as signified by the single forward slash at the end
8095 of the listing -- <quote> / </quote>.
8099 But we have defined additional actions that would be exceptions to these general
8100 rules, and then we list specific URLs (or patterns) that these exceptions
8101 would apply to. Last match wins. Just below this then are two explicit
8102 matches for <quote>.google.com</quote>. The first is negating our previous
8103 cookie setting, which was for <link
8104 linkend="SESSION-COOKIES-ONLY"><quote>+session-cookies-only</quote></link>
8105 (i.e. not persistent). So we will allow persistent cookies for google, at
8106 least that is how it is in this example. The second turns
8107 <emphasis>off</emphasis> any <link
8108 linkend="FAST-REDIRECTS"><quote>+fast-redirects</quote></link>
8109 action, allowing this to take place unmolested. Note that there is a leading
8110 dot here -- <quote>.google.com</quote>. This will match any hosts and
8111 sub-domains, in the google.com domain also, such as
8112 <quote>www.google.com</quote> or <quote>mail.google.com</quote>. But it would not
8113 match <quote>www.google.de</quote>! So, apparently, we have these two actions
8114 defined as exceptions to the general rules at the top somewhere in the lower
8115 part of our <filename>default.action</filename> file, and
8116 <quote>google.com</quote> is referenced somewhere in these latter sections.
8120 Then, for our <filename>user.action</filename> file, we again have no hits.
8121 So there is nothing google-specific that we might have added to our own, local
8122 configuration. If there was, those actions would over-rule any actions from
8123 previously processed files, such as <filename>default.action</filename>.
8124 <filename>user.action</filename> typically has the last word. This is the
8125 best place to put hard and fast exceptions,
8129 And finally we pull it all together in the bottom section and summarize how
8130 <application>Privoxy</application> is applying all its <quote>actions</quote>
8131 to <quote>google.com</quote>:
8142 +change-x-forwarded-for{block}
8143 -client-header-filter{hide-tor-exit-notation}
8144 -content-type-overwrite
8145 -crunch-client-header
8146 -crunch-if-none-match
8147 -crunch-incoming-cookies
8148 -crunch-outgoing-cookies
8149 -crunch-server-header
8150 +deanimate-gifs {last}
8151 -downgrade-http-version
8154 -filter {content-cookies}
8155 -filter {all-popups}
8156 -filter {banners-by-link}
8157 -filter {tiny-textforms}
8158 -filter {frameset-borders}
8159 -filter {demoronizer}
8160 -filter {shockwave-flash}
8161 -filter {quicktime-kioskmode}
8163 -filter {crude-parental}
8164 -filter {site-specifics}
8165 -filter {js-annoyances}
8166 -filter {html-annoyances}
8167 +filter {refresh-tags}
8168 -filter {unsolicited-popups}
8169 +filter {img-reorder}
8170 +filter {banners-by-size}
8172 +filter {jumping-windows}
8173 +filter {ie-exploits}
8180 -handle-as-empty-document
8182 -hide-accept-language
8183 -hide-content-disposition
8184 +hide-from-header {block}
8185 -hide-if-modified-since
8186 +hide-referrer {forge}
8189 -overwrite-last-modified
8190 -prevent-compression
8192 -server-header-filter{xml-to-html}
8193 -server-header-filter{html-to-xml}
8194 -session-cookies-only
8195 +set-image-blocker {pattern} </screen>
8199 Notice the only difference here to the previous listing, is to
8200 <quote>fast-redirects</quote> and <quote>session-cookies-only</quote>,
8201 which are activated specifically for this site in our configuration,
8202 and thus show in the <quote>Final Results</quote>.
8206 Now another example, <quote>ad.doubleclick.net</quote>:
8212 { +block{Domains starts with "ad"} }
8215 { +block{Domain contains "ad"} }
8218 { +block{Doubleclick banner server} +handle-as-image }
8219 .[a-vx-z]*.doubleclick.net
8224 We'll just show the interesting part here - the explicit matches. It is
8225 matched three different times. Two <quote>+block{}</quote> sections,
8226 and a <quote>+block{} +handle-as-image</quote>,
8227 which is the expanded form of one of our aliases that had been defined as:
8228 <quote>+block-as-image</quote>. (<link
8229 linkend="ALIASES"><quote>Aliases</quote></link> are defined in
8230 the first section of the actions file and typically used to combine more
8235 Any one of these would have done the trick and blocked this as an unwanted
8236 image. This is unnecessarily redundant since the last case effectively
8237 would also cover the first. No point in taking chances with these guys
8238 though ;-) Note that if you want an ad or obnoxious
8239 URL to be invisible, it should be defined as <quote>ad.doubleclick.net</quote>
8240 is done here -- as both a <link
8241 linkend="BLOCK"><quote>+block{}</quote></link>
8242 <emphasis>and</emphasis> an
8243 <link linkend="HANDLE-AS-IMAGE"><quote>+handle-as-image</quote></link>.
8244 The custom alias <quote><literal>+block-as-image</literal></quote> just
8245 simplifies the process and make it more readable.
8249 One last example. Let's try <quote>http://www.example.net/adsl/HOWTO/</quote>.
8250 This one is giving us problems. We are getting a blank page. Hmmm ...
8256 Matches for http://www.example.net/adsl/HOWTO/:
8258 In file: default.action <guibutton>[ View ]</guibutton> <guibutton>[ Edit ]</guibutton>
8262 +change-x-forwarded-for{block}
8263 -client-header-filter{hide-tor-exit-notation}
8264 -content-type-overwrite
8265 -crunch-client-header
8266 -crunch-if-none-match
8267 -crunch-incoming-cookies
8268 -crunch-outgoing-cookies
8269 -crunch-server-header
8271 -downgrade-http-version
8272 +fast-redirects {check-decoded-url}
8274 -filter {content-cookies}
8275 -filter {all-popups}
8276 -filter {banners-by-link}
8277 -filter {tiny-textforms}
8278 -filter {frameset-borders}
8279 -filter {demoronizer}
8280 -filter {shockwave-flash}
8281 -filter {quicktime-kioskmode}
8283 -filter {crude-parental}
8284 -filter {site-specifics}
8285 -filter {js-annoyances}
8286 -filter {html-annoyances}
8287 +filter {refresh-tags}
8288 -filter {unsolicited-popups}
8289 +filter {img-reorder}
8290 +filter {banners-by-size}
8292 +filter {jumping-windows}
8293 +filter {ie-exploits}
8300 -handle-as-empty-document
8302 -hide-accept-language
8303 -hide-content-disposition
8304 +hide-from-header{block}
8305 +hide-referer{forge}
8307 -overwrite-last-modified
8308 +prevent-compression
8310 -server-header-filter{xml-to-html}
8311 -server-header-filter{html-to-xml}
8312 +session-cookies-only
8313 +set-image-blocker{blank} }
8316 { +block{Path contains "ads".} +handle-as-image }
8322 Ooops, the <quote>/adsl/</quote> is matching <quote>/ads</quote> in our
8323 configuration! But we did not want this at all! Now we see why we get the
8324 blank page. It is actually triggering two different actions here, and
8325 the effects are aggregated so that the URL is blocked, and &my-app; is told
8326 to treat the block as if it were an image. But this is, of course, all wrong.
8327 We could now add a new action below this (or better in our own
8328 <filename>user.action</filename> file) that explicitly
8329 <emphasis>un</emphasis> blocks (
8330 <link linkend="BLOCK"><quote>{-block}</quote></link>) paths with
8331 <quote>adsl</quote> in them (remember, last match in the configuration
8332 wins). There are various ways to handle such exceptions. Example:
8344 Now the page displays ;-)
8345 Remember to flush your browser's caches when making these kinds of changes to
8346 your configuration to insure that you get a freshly delivered page! Or, try
8347 using <literal>Shift+Reload</literal>.
8351 But now what about a situation where we get no explicit matches like
8358 { +block{Path starts with "ads".} +handle-as-image }
8364 That actually was very helpful and pointed us quickly to where the problem
8365 was. If you don't get this kind of match, then it means one of the default
8366 rules in the first section of <filename>default.action</filename> is causing
8367 the problem. This would require some guesswork, and maybe a little trial and
8368 error to isolate the offending rule. One likely cause would be one of the
8369 <link linkend="FILTER"><quote>+filter</quote></link> actions.
8370 These tend to be harder to troubleshoot.
8371 Try adding the URL for the site to one of aliases that turn off
8372 <link linkend="FILTER"><quote>+filter</quote></link>:
8380 .worldpay.com # for quietpc.com
8388 <quote><literal>{ shop }</literal></quote> is an <quote>alias</quote> that expands to
8389 <quote><literal>{ -filter -session-cookies-only }</literal></quote>.
8390 Or you could do your own exception to negate filtering:
8398 # Disable ALL filter actions for sites in this section
8406 This would turn off all filtering for these sites. This is best
8407 put in <filename>user.action</filename>, for local site
8408 exceptions. Note that when a simple domain pattern is used by itself (without
8409 the subsequent path portion), all sub-pages within that domain are included
8410 automatically in the scope of the action.
8414 Images that are inexplicably being blocked, may well be hitting the
8415 <link linkend="FILTER-BANNERS-BY-SIZE"><quote>+filter{banners-by-size}</quote></link>
8417 that images of certain sizes are ad banners (works well
8418 <emphasis>most of the time</emphasis> since these tend to be standardized).
8422 <quote><literal>{ fragile }</literal></quote> is an alias that disables most
8423 actions that are the most likely to cause trouble. This can be used as a
8424 last resort for problem sites.
8430 # Handle with care: easy to break
8432 mybank.example.com</screen>
8437 <emphasis>Remember to flush caches!</emphasis> Note that the
8438 <literal>mail.google</literal> reference lacks the TLD portion (e.g.
8439 <quote>.com</quote>). This will effectively match any TLD with
8440 <literal>google</literal> in it, such as <literal>mail.google.de.</literal>,
8444 If this still does not work, you will have to go through the remaining
8445 actions one by one to find which one(s) is causing the problem.
8454 This program is free software; you can redistribute it
8455 and/or modify it under the terms of the GNU General
8456 Public License as published by the Free Software
8457 Foundation; either version 2 of the License, or (at
8458 your option) any later version.
8460 This program is distributed in the hope that it will
8461 be useful, but WITHOUT ANY WARRANTY; without even the
8462 implied warranty of MERCHANTABILITY or FITNESS FOR A
8463 PARTICULAR PURPOSE. See the GNU General Public
8464 License for more details.
8466 The GNU General Public License should be included with
8467 this file. If not, you can view it at
8468 http://www.gnu.org/copyleft/gpl.html
8469 or write to the Free Software Foundation, Inc.,
8470 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301,
projects / privoxy.git / blob