X-Git-Url: http://www.privoxy.org/gitweb/?a=blobdiff_plain;ds=sidebyside;f=doc%2Fwebserver%2Fuser-manual%2Factions-file.html;h=ed6ffe402479d28e49c8d3f56b2b6feb3edffa9c;hb=66237b3fc4eb5187c29d7bc598a87676db5b780b;hp=ca87032f06d8e9a4736bc85fe456097582ed56e6;hpb=80b13c5019d561424b3ed8224b6dc4e830e24f67;p=privoxy.git diff --git a/doc/webserver/user-manual/actions-file.html b/doc/webserver/user-manual/actions-file.html index ca87032f..ed6ffe40 100644 --- a/doc/webserver/user-manual/actions-file.html +++ b/doc/webserver/user-manual/actions-file.html @@ -1,22 +1,28 @@ + Actions Files + +

-

The list of actions files to be used are defined in the main configuration - file, and are processed in the order they are defined. The content of these - can all be viewed and edited from default.action is typically processed before + user.action). The content of these can all be viewed and + edited from http://config.privoxy.org/show-status.

. + The over-riding principle when applying actions, is that the last action that + matches a given URL wins. The broadest, most general rules go first + (defined in default.action), + followed by any exceptions (typically also in + default.action), which are then followed lastly by any + local preferences (typically in user.action). + Generally, user.action has the last word. +

An actions file typically has multiple sections. If you want to use alias section at the top of that file. Then comes the default set of rules which will apply universally to all - sites and pages (be very careful with using such a universal set in default.action, - with the advantage that is a separate file, which makes preserving your + with the advantage that it is a separate file, which makes preserving your personal settings across Privoxy

Actions can be used to block anything you want, including ads, banners, or - just some obnoxious URL that you would rather not see. Cookies can be accepted + just some obnoxious URL whose content you would rather not see. Cookies can be accepted or rejected, or accepted only during the current browser session (i.e. not - written to disk), content can be modified, JavaScripts tamed, user-tracking + written to disk), content can be modified, some JavaScripts tamed, user-tracking fooled, and much more. See below for a complete list @@ -201,7 +501,7 @@ CLASS="SECT2" >

8.1. Finding the Right Mix

, like cookie suppression or script disabling, may render some sites unusable that rely on these techniques to work properly. Finding the right mix of actions is not always easy and - certainly a matter of personal taste. In general, it can be said that the more + certainly a matter of personal taste. And, things can always change, requiring + refinements in the configuration. In general, it can be said that the more "aggressive""trusted" sites you - will have to make later. If, for example, you want to kill popup windows per + will have to make later. If, for example, you want to crunch all cookies per default, you'll have to make exceptions from that rule for sites that you - regularly use and that require popups for actually useful content, like maybe + regularly use and that require cookies for actually useful purposes, like maybe your bank, favorite shop, or newspaper.

We have tried to provide you with reasonable rules to start from in the @@ -235,7 +536,7 @@ CLASS="SECT2" >

8.2. How to Edit

http://config.privoxy.org/show-status. - The editor allows both fine-grained control over every single feature on a - per-URL basis, and easy choosing from wholesale sets of defaults like - enable-edit-actions must be enabled for + this to work. The editor allows both fine-grained control over every single + feature on a per-URL basis, and easy choosing from wholesale sets of defaults + like "Cautious", "Medium" or or + "Advanced".

. Warning: the "Advanced" setting is more + aggressive, and will be more likely to cause problems for some sites. + Experienced users only! +

If you prefer plain text editing to GUIs, you can of course also directly edit the - the actions files. Look at default.action which is richly - commented.

which is richly commented with many + good examples.

8.3. How Actions are Applied to URLs8.3. How Actions are Applied to Requests

Actions files are divided into sections. There are special sections, @@ -285,20 +598,24 @@ HREF="actions-file.html#ALIASES" be discussed later. For now let's concentrate on regular sections: They have a heading line (often split up to multiple lines for readability) which consist of a list of actions, separated by whitespace and enclosed in curly braces. - Below that, there is a list of URL patterns, each on a separate line.

To determine which actions apply to a request, the URL of the request is - compared to all patterns in each action file file. Every time it matches, the list of - applicable actions for the URL is incrementally updated, using the heading - of the section in which the pattern is located. If multiple matches for - the same URL set the same action differently, the last match wins. If not, - the effects are aggregated. E.g. a URL might match a regular section with - a heading line of "action file". + Every time it matches, the list of applicable actions for the request is + incrementally updated, using the heading of the section in which the + pattern is located. The same is done again for tags and tag patterns later on.

If multiple applying sections set the same action differently, + the last match wins. If not, the effects are aggregated. + E.g. a URL might match a regular section with a heading line of { +handle-as-image }, @@ -307,25 +624,54 @@ CLASS="LITERAL" >{ +block }, resulting - in both actions to apply.

actions to apply. And there may well be + cases where you will want to combine actions together. Such a section then + might look like:

  { +handle-as-image  +block{Banner ads.} }
+  # Block these as if they were images. Send no block page.
+   banners.example.com
+   media.example.com/.*banners
+   .example.com/images/ads/
+

You can trace this process for any given URL by visiting You can trace this process for URL patterns and any given URL by visiting http://config.privoxy.org/show-url-info.

More detail on this is provided in the Appendix, Examples and more detail on this is provided in the Appendix, Anatomy of an Action.

Troubleshooting: Anatomy of an Action section.

8.4. Patterns

Generally, a pattern has the form + As mentioned, Privoxy uses "patterns" + to determine what actions might apply to which sites and + pages your browser attempts to access. These "patterns" use wild + card type pattern matching to achieve a high degree of + flexibility. This allows one expression to be expanded and potentially match + against many similar patterns.

Generally, an URL pattern has the form + <domain>/<path>, - where both the <domain><port>/<path>, where the + <domain> and , the <path><port> - are optional. (This is why the pattern <path> are optional. (This is why the special + / matches all URLs).

pattern matches all URLs). Note that the protocol + portion of the URL pattern (e.g. http://) should + not be included in the pattern. This is assumed already!

The pattern matching syntax is different for the domain and path parts of + the URL. The domain part uses a simple globbing type matching technique, + while the path part uses more flexible + "Regular + Expressions" (POSIX 1003.2).

The port part of a pattern is a decimal port number preceded by a colon + (:). If the domain part contains a numerical IPv6 address, + it has to be put into angle brackets + (<, >).

www.example.com, - regardless of which document on that server is requested. + regardless of which document on that server is requested. So ALL pages in + this domain would be covered by the scope of this action. Note that a + simple example.com is different and would NOT match.

matches all the documents on www.example.com + whose name starts with /index.html. +

www.example.com/index.html$

matches only the single document /index.html

/index.html/index.html$

/index.html, regardless of the domain, - i.e. on any web server. +> web server anywhere.

index.html:8000/

matches nothing, since it would be interpreted as a domain name and - there is no top-level domain called .html. +> Matches any URL pointing to TCP port 8000. +

<2001:db8::1>/

Matches any URL with the host address 2001:db8::1. + (Note that the real URL uses plain brackets, not angle brackets.) +

index.html

matches nothing, since it would be interpreted as a domain name and + there is no top-level domain called .html. So its + a mistake.

8.4.1. The Domain Pattern

matches any domain that ENDS in - matches any domain with first-level domain .example.comcom + and second-level domain example. + For example www.example.com, + example.com and foo.bar.baz.example.com. + Note that it wouldn't match if the second-level domain was another-example.

matches any domain that matches any domain that STARTS with www. +> (It also matches the domain + www but most of the time that doesn't matter.)

matches any domain that matches any domain that CONTAINS .example. - (Correctly speaking: It matches any FQDN that contains . + And, by the way, also included would be any files or documents that exist + within that domain since no path limitations are specified. (Correctly + speaking: It matches any FQDN that contains example as a domain.) +> as + a domain.) This might be www.example.com, + news.example.de, or + www.example.net/cgi/testing.pl for instance. All these + cases are matched.

Additionally, there are wild-cards that you can use in the domain names - themselves. They work pretty similar to shell wild-cards: "*" - stands for zero or more arbitrary characters, represents zero or more arbitrary characters (this is + equivalent to the + "Regular + Expression" based syntax of ".*"), + "?" stands for - any single character, you can define character classes in square - brackets and all of that can be freely mixed:

represents any single character (this is equivalent to the + regular expression syntax of a simple "."), and you can define + "character classes" in square brackets which is similar to + the same regular expression technique. All of this can be freely mixed:

wwwz.example.com etc., but etc., but not

While flexible, this is not the sophistication of full regular expression based syntax.

8.4.2. The Path Pattern

Privoxy uses Perl compatible regular expressions - (through the uses "modern" POSIX 1003.2 + PCRE library) for - matching the path.

"Regular + Expressions" for matching the path portion (after the slash), + and is thus more flexible.

There is an Appendix with a brief quick-start into regular - expressions, and full (very technical) documentation on PCRE regex syntax is available on-line - at http://www.pcre.org/man.txt. - You might also find the Perl man page on regular expressions (man perlre) - useful, which is available on-line at http://www.perldoc.com/perl5.6/pod/perlre.html.

man re_format
).

Note that the path pattern is automatically left-anchored at the (regular expression speak for the beginning of a line).

Please also note that matching in the path is Please also note that matching in the path is CASE INSENSITIVE by default, but you can switch to case sensitive at any point in the pattern by using the PaTtErN in - exactly this capitalization.

.example.com/.*

Is equivalent to just ".example.com", since any documents + within that domain are matched with or without the ".*" + regular expression. This is redundant +

.example.com/.*/index.html$

Will match any page in the domain of "example.com" that is + named "index.html", and that is part of some path. For + example, it matches "www.example.com/testing/index.html" but + NOT "www.example.com/index.html" because the regular + expression called for at least two "/'s", thus the path + requirement. It also would match + "www.example.com/testing/index_html", because of the + special meta-character ".". +

.example.com/(.*/)?index\.html$

This regular expression is conditional so it will match any page + named "index.html" regardless of path which in this case can + have one or more "/'s". And this one must contain exactly + ".html" (but does not have to end with that!). +

.example.com/(.*/)(ads|banners?|junk)

This regular expression will match any path of "example.com" + that contains any of the words "ads", "banner", + "banners" (because of the "?") or "junk". + The path does not have to end in these words, just contain them. +

.example.com/(.*/)(ads|banners?|junk)/.*\.(jpe?g|gif|png)$

This is very much the same as above, except now it must end in either + ".jpg", ".jpeg", ".gif" or ".png". So this + one is limited to common image formats. +

There are many, many good examples to be found in default.action, + and more tutorials below in Appendix on regular expressions.

8.4.3. The Tag Pattern

Tag patterns are used to change the applying actions based on the + request's tags. Tags can be created with either the + client-header-tagger + or the server-header-tagger action.

Tag patterns have to start with "TAG:", so Privoxy + can tell them apart from URL patterns. Everything after the colon + including white space, is interpreted as a regular expression with + path pattern syntax, except that tag patterns aren't left-anchored + automatically (Privoxy doesn't silently add a "^", + you have to do it yourself if you need it).

To match all requests that are tagged with "foo" + your pattern line should be "TAG:^foo$", + "TAG:foo" would work as well, but it would also + match requests whose tags contain "foo" somewhere. + "TAG: foo" wouldn't work as it requires white space.

Sections can contain URL and tag patterns at the same time, + but tag patterns are checked after the URL patterns and thus + always overrule them, even if they are located before the URL patterns.

Once a new tag is added, Privoxy checks right away if it's matched by one + of the tag patterns and updates the action settings accordingly. As a result + tags can be used to activate other tagger actions, as long as these other + taggers look for headers that haven't already be parsed.

For example you could tag client requests which use the + POST method, + then use this tag to activate another tagger that adds a tag if cookies + are sent, and then use a block action based on the cookie tag. This allows + the outcome of one action, to be input into a subsequent action. However if + you'd reverse the position of the described taggers, and activated the + method tagger based on the cookie tagger, no method tags would be created. + The method tagger would look for the request line, but at the time + the cookie tag is created, the request line has already been parsed.

While this is a limitation you should be aware of, this kind of + indirection is seldom needed anyway and even the example doesn't + make too much sense.

- There are three classes of actions:

Example: +block+handle-as-image

Example: +hide-user-agent{ Mozilla 1.0 }+hide-user-agent{Mozilla/5.0 (X11; U; FreeBSD i386; en-US; rv:1.8.1.4) Gecko/20070602 Firefox/2.0.0.4}

Multi-value. These look exactly like parameterized actions, but they behave differently: If the action applies multiple times to the - same URL, but with different parameters, all the parameters - from all matches are remembered. This is used for actions that can be executed for the same request repeatedly, like adding multiple headers, or filtering through multiple filters. Syntax: @@ -945,21 +1723,29 @@ CLASS="QUOTE" CLASS="APPLICATION" >Privoxy would just be a - normal, non-blocking, non-anonymizing proxy. You must specifically enable the + normal, non-blocking, non-filtering proxy. You must specifically enable the privacy and blocking features you need (although the provided default actions files will give a good starting point).

Later defined actions always over-ride earlier ones. So exceptions - to any rules you make, should come in the latter part of the file (or - in a file that is processed later when using multiple actions files). For - multi-valued actions, the actions are applied in the order they are specified. - Actions files are processed in the order they are defined in - Later defined action sections always over-ride earlier ones of the same type. + So exceptions to any rules you make, should come in the latter part of the file (or + in a file that is processed later when using multiple actions files such + as user.action). For multi-valued actions, the actions + are applied in the order they are specified. Actions files are processed in + the order they are defined in config (the default installation has three actions - files). It also quite possible for any given URL pattern to match more than - one pattern and thus more than one set of actions!

(the default + installation has three actions files). It also quite possible for any given + URL to match more than one "pattern" (because of wildcards and + regular expressions), and thus to trigger more than one set of actions! Last + match wins.

The list of valid are, you definitely don't need to worry about this one.

Headers added by this action are not modified by other actions. +

Example usage:
Typical use:

Block ads or other obnoxious content

Block ads or other unwanted content

Effect:

Requests for URLs to which this action applies are blocked, i.e. the requests are not - forwarded to the remote server, but answered locally with a substitute page or image, - as determined by the Requests for URLs to which this action applies are blocked, i.e. the + requests are trapped by Privoxy and the requested URL is never retrieved, + but is answered locally with a substitute page or image, as determined by + the handle-as-image - and , + set-image-blocker, and + handle-as-empty-document actions. +

Type:

Boolean.

Parameterized.

Parameter:

N/A

A block reason that should be given to the user.

Notes:
"BLOCKED" page - for requests to blocked pages. This page contains links to find out why the request - was blocked, and a click-through to the blocked content (the latter only if compiled with the - force feature enabled). The "BLOCKED" page adapts to the available - screen space -- it displays full-blown if space allows, or miniaturized and text-only - if loaded into a small frame or window. If you are using Privoxy - right now, you can take a look at the - "BLOCKED" - page. + for requests to blocked pages. This page contains the block reason given as + parameter, a link to find out why the block action applies, and a click-through + to the blocked content (the latter only if the force feature is available and + enabled).

- A very important exception occurs if both Privoxy deals with - ads and other unwanted content. + ads and other unwanted content. Blocking is a core feature, and one + upon which various other features depend.

The

{+block}      # Block and replace with "blocked" page
-.nasty-stuff.example.com
+>{+block{No nasty stuff for you.}}
+# Block and replace with "blocked" page
+ .nasty-stuff.example.com
 
-{+block +handle-as-image} # Block and replace with image
-.ad.doubleclick.net
-.ads.r.us

8.5.3. crunch-incoming-cookies8.5.3. change-x-forwarded-for

Typical use:

Prevent the web server from setting any cookies on your system -

Improve privacy by not forwarding the source of the request in the HTTP headers.

Effect:

Deletes any Deletes the "Set-Cookie:" HTTP headers from server replies. +>"X-Forwarded-For:" HTTP header from the client request, + or adds a new one.

Type:

Boolean.

Parameterized.

Parameter:

N/A -

Notes:

This action is only concerned with incoming cookies. For - outgoing cookies, use -

  • "block" to delete the header.

  • "add" to create the header (or append + the client's IP address to an already existing one). +

Notes:

It is safe and recommended to use crunch-outgoing-cookiesblock. - Use both to disable cookies completely.

It makes no sense at all to use this action in conjunction - with the session-cookies-only action, - since it would prevent the session cookies from being set. +> Forwarding the source address of the request may make + sense in some multi-user setups but is also a privacy risk.

Example usage:

+crunch-incoming-cookies
+change-x-forwarded-for{block}

8.5.4. crunch-outgoing-cookies8.5.4. client-header-filter

Typical use:

Prevent the web server from reading any cookies from your system +> Rewrite or remove single client headers.

Effect:

Deletes any "Cookie:" HTTP headers from client requests. +> All client headers to which this action applies are filtered on-the-fly through + the specified regular expression based substitutions.

Type:

Boolean.

Parameterized.

Parameter:

N/A +> The name of a client-header filter, as defined in one of the + filter files.

Notes:

This action is only concerned with outgoing cookies. For - incoming cookies, use - crunch-incoming-cookies. - Use both to disable cookies completely. +> Client-header filters are applied to each header on its own, not to + all at once. This makes it easier to diagnose problems, but on the downside + you can't write filters that only change header x if header y's value is z. + You can do that by using tags though.

It makes no sense at all to use this action in conjunction - with the session-cookies-only action, - since it would prevent the session cookies from being read. +> Client-header filters are executed after the other header actions have finished + and use their output as input. +

If the request URL gets changed, Privoxy will detect that and use the new + one. This can be used to rewrite the request destination behind the client's + back, for example to specify a Tor exit relay for certain requests. +

Please refer to the filter file chapter + to learn which client-header filters are available by default, and how to + create your own.

Example usage:
Example usage (section):

+crunch-outgoing-cookies
# Hide Tor exit notation in Host and Referer Headers +{+client-header-filter{hide-tor-exit-notation}} +/ +
-

8.5.5. deanimate-gifs8.5.5. client-header-tagger

Typical use:

Stop those annoying, distracting animated GIF images.

Block requests based on their headers. +

Effect:

De-animate GIF animations, i.e. reduce them to their first or last image. +> Client headers to which this action applies are filtered on-the-fly through + the specified regular expression based substitutions, the result is used as + tag.

Parameter:

"last" or "first" +> The name of a client-header tagger, as defined in one of the + filter files.

Notes:

This will also shrink the images considerably (in bytes, not pixels!). If - the option "first" is given, the first frame of the animation - is used as the replacement. If Client-header taggers are applied to each header on its own, + and as the header isn't modified, each tagger "last" is given, the last - frame of the animation is used instead, which probably makes more sense for - most banner animations, but also has the risk of not showing the entire - last frame (if it is only a delta to an earlier frame). +>"sees" + the original.

You can safely use this action with patterns that will also match non-GIF - objects, because no attempt will be made at anything that doesn't look like - a GIF. +> Client-header taggers are the first actions that are executed + and their tags can be used to control every other action.

Example usage:
Example usage (section):

+deanimate-gifs{last}
# Tag every request with the User-Agent header +{+client-header-tagger{user-agent}} +/ + +# Tagging itself doesn't change the action +# settings, sections with TAG patterns do: +# +# If it's a download agent, use a different forwarding proxy, +# show the real User-Agent and make sure resume works. +{+forward-override{forward-socks5 10.0.0.2:2222 .} \ + -hide-if-modified-since \ + -overwrite-last-modified \ + -hide-user-agent \ + -filter \ + -deanimate-gifs \ +} +TAG:^User-Agent: NetBSD-ftp/ +TAG:^User-Agent: Novell ZYPP Installer +TAG:^User-Agent: RPM APT-HTTP/ +TAG:^User-Agent: fetch libfetch/ +TAG:^User-Agent: Ubuntu APT-HTTP/ +TAG:^User-Agent: MPlayer/ +

8.5.6. downgrade-http-version8.5.6. content-type-overwrite

Typical use:

Work around (very rare) problems with HTTP/1.1

Stop useless download menus from popping up, or change the browser's rendering mode

Effect:

Downgrades HTTP/1.1 client requests and server replies to HTTP/1.0. +> Replaces the "Content-Type:" HTTP server header.

Type:

Boolean.

Parameterized.

Parameter:

N/A +> Any string.

Notes:

This is a left-over from the time when The "Content-Type:" HTTP server header is used by the + browser to decide what to do with the document. The value of this + header can cause the browser to open a download menu instead of + displaying the document by itself, even if the document's format is + supported by the browser. +

The declared content type can also affect which rendering mode + the browser chooses. If XHTML is delivered as "text/html", + many browsers treat it as yet another broken HTML document. + If it is send as "application/xml", browsers with + XHTML support will only display it, if the syntax is correct. +

If you see a web site that proudly uses XHTML buttons, but sets + "Content-Type: text/html", you can use Privoxy - didn't support important HTTP/1.1 features well. It is left here for the - unlikely case that you experience HTTP/1.1 related problems with some server - out there. Not all (optional) HTTP/1.1 features are supported yet, so there - is a chance you might need this action. + to overwrite it with "application/xml" and validate + the web master's claim inside your XHTML-supporting browser. + If the syntax is incorrect, the browser will complain loudly. +

You can also go the opposite direction: if your browser prints + error messages instead of rendering a document falsely declared + as XHTML, you can overwrite the content type with + "text/html" and have it rendered as broken HTML document. +

By default content-type-overwrite only replaces + "Content-Type:" headers that look like some kind of text. + If you want to overwrite it unconditionally, you have to combine it with + force-text-mode. + This limitation exists for a reason, think twice before circumventing it. +

Most of the time it's easier to replace this action with a custom + server-header filter. + It allows you to activate it for every document of a certain site and it will still + only replace the content types you aimed at. +

Of course you can apply content-type-overwrite + to a whole site and then make URL based exceptions, but it's a lot + more work to get the same precision.

Example usage (section):
Example usage (sections):

{+downgrade-http-version}
-problem-host.example.com
# Check if www.example.net/ really uses valid XHTML +{ +content-type-overwrite{application/xml} } +www.example.net/ + +# but leave the content type unmodified if the URL looks like a style sheet +{-content-type-overwrite} +www.example.net/.*\.css$ +www.example.net/.*style
-

8.5.7. fast-redirects8.5.7. crunch-client-header

Typical use:

Fool some click-tracking scripts and speed up indirect links

Remove a client header Privoxy has no dedicated action for.

Effect:

Cut off all but the last valid URL from requests. +> Deletes every header sent by the client that contains the string the user supplied as parameter.

Type:

Boolean.

Parameterized.

Parameter:

N/A +> Any string.

Notes:

- Many sites, like yahoo.com, don't just link to other sites. Instead, they - will link to some script on their own servers, giving the destination as a - parameter, which will then redirect you to the final target. URLs - resulting from this scheme typically look like: - http://some.place/click-tracker.cgi?target=http://some.where.else. -

This action allows you to block client headers for which no dedicated + Privoxy action exists. + Privoxy will remove every client header that + contains the string you supplied as parameter. +

Sometimes, there are even multiple consecutive redirects encoded in the - URL. These redirections via scripts make your web browsing more traceable, - since the server from which you follow such a link can see where you go - to. Apart from that, valuable bandwidth and time is wasted, while your - browser ask the server for one redirect after the other. Plus, it feeds - the advertisers. +> Regular expressions are not supported and you can't + use this action to block different headers in the same request, unless + they contain the same string.

This feature is currently not very smart and is scheduled for improvement. - It is likely to break some sites. You should expect to need possibly - many exceptions to this action, if it is enabled by default in +> crunch-client-header is only meant for quick tests. + If you have to block several different headers, or only want to modify + parts of them, you should use a default.action. Some sites just don't work without - it. +CLASS="LITERAL" +>client-header filter.

Warning

Don't block any header without understanding the consequences. +

Example usage:
Example usage (section):

{+fast-redirects}
# Block the non-existent "Privacy-Violation:" client header +{ +crunch-client-header{Privacy-Violation:} } +/ +
-

8.5.8. filter8.5.8. crunch-if-none-match

Typical use:

Get rid of HTML and JavaScript annoyances, banner advertisements (by size), do fun text replacements, etc.

Prevent yet another way to track the user's steps between sessions.

Effect:

Text documents, including HTML and JavaScript, to which this action applies, are filtered on-the-fly - through the specified regular expression based substitutions. +> Deletes the "If-None-Match:" HTTP client header.

Type:

Parameterized.

Boolean.

Parameter:

The name of a filter, as defined in the filter file - (typically default.filter, set by the - filterfile - option in the config file) +> N/A

Notes:

For your convenience, there are a bunch of pre-defined filters available - in the distribution filter file that you can use. See the example below for - a list. +> Removing the "If-None-Match:" HTTP client header + is useful for filter testing, where you want to force a real + reload instead of getting status code "304" which + would cause the browser to use a cached copy of the page.

This is potentially a very powerful feature! But "rolling your own" - filters requires a knowledge of regular expressions and HTML. +> It is also useful to make sure the header isn't used as a cookie + replacement (unlikely but possible).

Filtering requires buffering the page content, which may appear to - slow down page rendering since nothing is displayed until all content has - passed the filters. (It does not really take longer, but seems that way - since the page is not incrementally displayed.) This effect will be more - noticeable on slower connections. +> Blocking the "If-None-Match:" header shouldn't cause any + caching problems, as long as the "If-Modified-Since:" header + isn't blocked or missing as well.

At this time, Privoxy cannot (yet!) uncompress compressed - documents. If you want filtering to work on all documents, even those that - would normally be sent compressed, use the +> It is recommended to use this action together with prevent-compressionhide-if-modified-since - action in conjunction with filter. -

Filtering can achieve some of the effects as the + and blockoverwrite-last-modified - action, i.e. it can be used to block ads and banners. -

Feedback with suggestions for new or improved filters is particularly - welcome! +>.

Example usage (with filters from the distribution default.filter file):
Example usage (section):

-
+filter{html-annoyances}     # Get rid of particularly annoying HTML abuse.
# Let the browser revalidate cached documents but don't +# allow the server to use the revalidation headers for user tracking. +{+hide-if-modified-since{-60} \ + +overwrite-last-modified{randomize} \ + +crunch-if-none-match} +/

8.5.9. crunch-incoming-cookies

Typical use:

Prevent the web server from setting HTTP cookies on your system +

Effect:

Deletes any "Set-Cookie:" HTTP headers from server replies. +

Type:

- Boolean.

Parameter:

N/A +

Notes:

This action is only concerned with incoming HTTP cookies. For + outgoing HTTP cookies, use + crunch-outgoing-cookies. + Use both to disable HTTP cookies completely. +

It makes no sense at all to use this action in conjunction + with the session-cookies-only action, + since it would prevent the session cookies from being set. See also + filter-content-cookies. +

Example usage:

+filter{js-annoyances}       # Get rid of particularly annoying JavaScript abuse
+crunch-incoming-cookies

8.5.10. crunch-server-header

Typical use:

Remove a server header Privoxy has no dedicated action for.

Effect:

Deletes every header sent by the server that contains the string the user supplied as parameter. +

Type:

Parameterized.

Parameter:

Any string. +

Notes:

This action allows you to block server headers for which no dedicated + Privoxy action exists. Privoxy -

Regular expressions are not supported and you can't + use this action to block different headers in the same request, unless + they contain the same string. +

crunch-server-header is only meant for quick tests. + If you have to block several different headers, or only want to modify + parts of them, you should use a custom + server-header filter. +

+filter{banners-by-size}     # Kill banners by size (very efficient!)
Warning

Don't block any header without understanding the consequences. +

-

Example usage (section):

-
+filter{content-cookies}     # Kill cookies that come sneaking in the HTML or JS content
# Crunch server headers that try to prevent caching +{ +crunch-server-header{no-cache} } +/

8.5.11. crunch-outgoing-cookies

Typical use:

Prevent the web server from reading any HTTP cookies from your system +

Effect:

Deletes any "Cookie:" HTTP headers from client requests. +

Type:

Boolean.

Parameter:

N/A +

Notes:

This action is only concerned with outgoing HTTP cookies. For + incoming HTTP cookies, use + crunch-incoming-cookies. + Use both to disable HTTP cookies completely. +

It makes no sense at all to use this action in conjunction + with the session-cookies-only action, + since it would prevent the session cookies from being read. +

Example usage:

+crunch-outgoing-cookies
-

8.5.12. deanimate-gifs

Typical use:

Stop those annoying, distracting animated GIF images.

Effect:

De-animate GIF animations, i.e. reduce them to their first or last image. +

Type:

Parameterized.

Parameter:

"last" or "first" +

Notes:

This will also shrink the images considerably (in bytes, not pixels!). If + the option "first" is given, the first frame of the animation + is used as the replacement. If "last" is given, the last + frame of the animation is used instead, which probably makes more sense for + most banner animations, but also has the risk of not showing the entire + last frame (if it is only a delta to an earlier frame). +

You can safely use this action with patterns that will also match non-GIF + objects, because no attempt will be made at anything that doesn't look like + a GIF. +

Example usage:

+filter{popups}              # Kill all popups in JS and HTML
+deanimate-gifs{last}
+

8.5.13. downgrade-http-version

Typical use:

Work around (very rare) problems with HTTP/1.1

Effect:

Downgrades HTTP/1.1 client requests and server replies to HTTP/1.0.

Type:

Boolean.

Parameter:

N/A +

Notes:

This is a left-over from the time when Privoxy -
Example usage (section):

+filter{webbugs}             # Squish WebBugs (1x1 invisible GIFs used for user tracking)
{+downgrade-http-version} +problem-host.example.com
+

8.5.14. fast-redirects

Typical use:

Fool some click-tracking scripts and speed up indirect links.

Effect:

Detects redirection URLs and redirects the browser without contacting + the redirection server first. +

Type:

Parameterized.

Parameter:

  • "simple-check" to just search for the string "http://" + to detect redirection URLs. +

  • "check-decoded-url" to decode URLs (if necessary) before searching + for redirection URLs. +

Notes:

+ Many sites, like yahoo.com, don't just link to other sites. Instead, they + will link to some script on their own servers, giving the destination as a + parameter, which will then redirect you to the final target. URLs + resulting from this scheme typically look like: + "http://www.example.org/click-tracker.cgi?target=http%3a//www.example.net/". +

Sometimes, there are even multiple consecutive redirects encoded in the + URL. These redirections via scripts make your web browsing more traceable, + since the server from which you follow such a link can see where you go + to. Apart from that, valuable bandwidth and time is wasted, while your + browser asks the server for one redirect after the other. Plus, it feeds + the advertisers. +

This feature is currently not very smart and is scheduled for improvement. + If it is enabled by default, you will have to create some exceptions to + this action. It can lead to failures in several ways: +

Not every URLs with other URLs as parameters is evil. + Some sites offer a real service that requires this information to work. + For example a validation service needs to know, which document to validate. + fast-redirects assumes that every URL parameter that + looks like another URL is a redirection target, and will always redirect to + the last one. Most of the time the assumption is correct, but if it isn't, + the user gets redirected anyway. +

Another failure occurs if the URL contains other parameters after the URL parameter. + The URL: + "http://www.example.org/?redirect=http%3a//www.example.net/&foo=bar". + contains the redirection URL "http://www.example.net/", + followed by another parameter. fast-redirects doesn't know that + and will cause a redirect to "http://www.example.net/&foo=bar". + Depending on the target server configuration, the parameter will be silently ignored + or lead to a "page not found" error. You can prevent this problem by + first using the redirect action + to remove the last part of the URL, but it requires a little effort. +

To detect a redirection URL, fast-redirects only + looks for the string "http://", either in plain text + (invalid but often used) or encoded as "http%3a//". + Some sites use their own URL encoding scheme, encrypt the address + of the target server or replace it with a database id. In theses cases + fast-redirects is fooled and the request reaches the + redirection server where it probably gets logged. +

Example usage:

 { +fast-redirects{simple-check} }
+   one.example.com 
+
+ { +fast-redirects{check-decoded-url} }
+   another.example.com/testing
+

8.5.15. filter

Typical use:

Get rid of HTML and JavaScript annoyances, banner advertisements (by size), + do fun text replacements, add personalized effects, etc.

Effect:

All instances of text-based type, most notably HTML and JavaScript, to which + this action applies, can be filtered on-the-fly through the specified regular + expression based substitutions. (Note: as of version 3.0.3 plain text documents + are exempted from filtering, because web servers often use the + text/plain MIME type for all files whose type they don't know.) +

Type:

Parameterized.

Parameter:

The name of a content filter, as defined in the filter file. + Filters can be defined in one or more files as defined by the + filterfile + option in the config file. + default.filter is the collection of filters + supplied by the developers. Locally defined filters should go + in their own file, such as user.filter. +

When used in its negative form, + and without parameters, all filtering is completely disabled. +

Notes:

For your convenience, there are a number of pre-defined filters available + in the distribution filter file that you can use. See the examples below for + a list. +

Filtering requires buffering the page content, which may appear to + slow down page rendering since nothing is displayed until all content has + passed the filters. (It does not really take longer, but seems that way + since the page is not incrementally displayed.) This effect will be more + noticeable on slower connections. +

"Rolling your own" + filters requires a knowledge of + "Regular + Expressions" and + "HTML". + This is very powerful feature, and potentially very intrusive. + Filters should be used with caution, and where an equivalent + "action" is not available. +

The amount of data that can be filtered is limited to the + buffer-limit + option in the main config file. The + default is 4096 KB (4 Megs). Once this limit is exceeded, the buffered + data, and all pending data, is passed through unfiltered. +

Inappropriate MIME types, such as zipped files, are not filtered at all. + (Again, only text-based types except plain text). Encrypted SSL data + (from HTTPS servers) cannot be filtered either, since this would violate + the integrity of the secure transaction. In some situations it might + be necessary to protect certain text, like source code, from filtering + by defining appropriate -filter exceptions. +

Compressed content can't be filtered either, unless Privoxy + is compiled with zlib support (requires at least Privoxy 3.0.7), + in which case Privoxy will decompress the content before filtering + it. +

If you use a Privoxy version without zlib support, but want filtering to work on + as much documents as possible, even those that would normally be sent compressed, + you must use the prevent-compression + action in conjunction with filter. +

Content filtering can achieve some of the same effects as the + block + action, i.e. it can be used to block ads and banners. But the mechanism + works quite differently. One effective use, is to block ad banners + based on their size (see below), since many of these seem to be somewhat + standardized. +

Feedback with suggestions for new or + improved filters is particularly welcome! +

The below list has only the names and a one-line description of each + predefined filter. There are more + verbose explanations of what these filters do in the filter file chapter. +

Example usage (with filters from the distribution default.filter file). + See the Predefined Filters section for + more explanation on each:

+
+filter{js-annoyances}       # Get rid of particularly annoying JavaScript abuse.
+

+
+filter{js-events}           # Kill all JS event bindings and timers (Radically destructive! Only for extra nasty sites).
+

+
+filter{html-annoyances}     # Get rid of particularly annoying HTML abuse.
+

+
+filter{content-cookies}     # Kill cookies that come in the HTML or JS content.
+

+
+filter{refresh-tags}        # Kill automatic refresh tags (for dial-on-demand setups).
+

+
+filter{unsolicited-popups}  # Disable only unsolicited pop-up windows. Useful if your browser lacks this ability.
+

+
+filter{all-popups}          # Kill all popups in JavaScript and HTML. Useful if your browser lacks this ability.
+

+
+filter{img-reorder}         # Reorder attributes in <img> tags to make the banners-by-* filters more effective.
+

+
+filter{banners-by-size}     # Kill banners by size.
+

+
+filter{banners-by-link}     # Kill banners by their links to known clicktrackers.
+

+
+filter{webbugs}             # Squish WebBugs (1x1 invisible GIFs used for user tracking).
+

+
+filter{tiny-textforms}      # Extend those tiny textareas up to 40x80 and kill the hard wrap.
+

+
+filter{jumping-windows}     # Prevent windows from resizing and moving themselves.
+

+
+filter{frameset-borders}    # Give frames a border and make them resizable.
+

+
+filter{demoronizer}         # Fix MS's non-standard use of standard charsets.
+

+
+filter{shockwave-flash}     # Kill embedded Shockwave Flash objects.
+

+
+filter{quicktime-kioskmode} # Make Quicktime movies saveable.
+

+
+filter{fun}                 # Text replacements for subversive browsing fun!
+

+
+filter{crude-parental}      # Crude parental filtering. Note that this filter doesn't work reliably.
+

+
+filter{ie-exploits}         # Disable some known Internet Explorer bug exploits.
+

+
+filter{site-specifics}      # Cure for site-specific problems. Don't apply generally!
+

+
+filter{no-ping}             # Removes non-standard ping attributes in <a> and <area> tags.
+

+
+filter{google}              # CSS-based block for Google text ads. Also removes a width limitation and the toolbar advertisement.
+

+
+filter{yahoo}               # CSS-based block for Yahoo text ads. Also removes a width limitation.
+

+
+filter{msn}                 # CSS-based block for MSN text ads. Also removes tracking URLs and a width limitation.
+

+
+filter{blogspot}            # Cleans up some Blogspot blogs. Read the fine print before using this.
+

8.5.16. force-text-mode

Typical use:

Force Privoxy to treat a document as if it was in some kind of text format.

Effect:

Declares a document as text, even if the "Content-Type:" isn't detected as such. +

Type:

Boolean.

Parameter:

N/A +

Notes:

As explained above, + Privoxy tries to only filter files that are + in some kind of text format. The same restrictions apply to + content-type-overwrite. + force-text-mode declares a document as text, + without looking at the "Content-Type:" first. +

Warning

Think twice before activating this action. Filtering binary data + with regular expressions can cause file damage. +

Example usage:

+force-text-mode
+     
+

8.5.17. forward-override

Typical use:

Change the forwarding settings based on User-Agent or request origin

Effect:

Overrules the forward directives in the configuration file. +

Type:

Multi-value.

Parameter:

  • "forward ." to use a direct connection without any additional proxies.

  • "forward 127.0.0.1:8123" to use the HTTP proxy listening at 127.0.0.1 port 8123. +

  • "forward-socks4a 127.0.0.1:9050 ." to use the socks4a proxy listening at + 127.0.0.1 port 9050. Replace "forward-socks4a" with "forward-socks4" + to use a socks4 connection (with local DNS resolution) instead, use "forward-socks5" + for socks5 connections (with remote DNS resolution). +

  • "forward-socks4a 127.0.0.1:9050 proxy.example.org:8000" to use the socks4a proxy + listening at 127.0.0.1 port 9050 to reach the HTTP proxy listening at proxy.example.org port 8000. + Replace "forward-socks4a" with "forward-socks4" to use a socks4 connection + (with local DNS resolution) instead, use "forward-socks5" + for socks5 connections (with remote DNS resolution). +

Notes:

This action takes parameters similar to the + forward directives in the configuration + file, but without the URL pattern. It can be used as replacement, but normally it's only + used in cases where matching based on the request URL isn't sufficient. +

Warning

Please read the description for the forward directives before + using this action. Forwarding to the wrong people will reduce your privacy and increase the + chances of man-in-the-middle attacks. +

If the ports are missing or invalid, default values will be used. This might change + in the future and you shouldn't rely on it. Otherwise incorrect syntax causes Privoxy + to exit. +

Use the show-url-info CGI page + to verify that your forward settings do what you thought the do. +

Example usage:

# Always use direct connections for requests previously tagged as
+# "User-Agent: fetch libfetch/2.0" and make sure
+# resuming downloads continues to work.
+# This way you can continue to use Tor for your normal browsing,
+# without overloading the Tor network with your FreeBSD ports updates
+# or downloads of bigger files like ISOs.
+# Note that HTTP headers are easy to fake and therefore their
+# values are as (un)trustworthy as your clients and users.
+{+forward-override{forward .} \
+ -hide-if-modified-since      \
+ -overwrite-last-modified     \
+}
+TAG:^User-Agent: fetch libfetch/2\.0$
+     
+

8.5.18. handle-as-empty-document

Typical use:

Mark URLs that should be replaced by empty documents if they get blocked

Effect:

This action alone doesn't do anything noticeable. It just marks URLs. + If the block action also applies, + the presence or absence of this mark decides whether an HTML "BLOCKED" + page, or an empty document will be sent to the client as a substitute for the blocked content. + The empty document isn't literally empty, but actually contains a single space. +

Type:

Boolean.

Parameter:

N/A

Notes:

Some browsers complain about syntax errors if JavaScript documents + are blocked with Privoxy's -
+filter{fun}                 # Text replacements for subversive browsing fun!
Privoxy + BLOCKED message in frames.

-
+filter{frameset-borders}    # Give frames a border and make them resizeable
+> The content type for the empty document can be specified with + content-type-overwrite{}, + but usually this isn't necessary.

Example usage:

-
+filter{refresh-tags}        # Kill automatic refresh tags (for dial-on-demand setups)
# Block all documents on example.org that end with ".js", +# but send an empty document instead of the usual HTML message. +{+block{Blocked JavaScript} +handle-as-empty-document} +example.org/.*\.js$ +

8.5.19. handle-as-image

-
+filter{nimda}               # Remove Nimda (virus) code.

Typical use:

Mark URLs as belonging to images (so they'll be replaced by images if they do get blocked, rather than HTML pages)

Effect:

This action alone doesn't do anything noticeable. It just marks URLs as images. + If the block action also applies, + the presence or absence of this mark decides whether an HTML "blocked" + page, or a replacement image (as determined by the set-image-blocker action) will be sent to the + client as a substitute for the blocked content.

Type:

- Boolean.

Parameter:

N/A +

Notes:

The below generic example section is actually part of default.action. + It marks all URLs with well-known image file name extensions as images and should + be left intact. +

Users will probably only want to use the handle-as-image action in conjunction with + block, to block sources of banners, whose URLs don't + reflect the file type, like in the second example section. +

Note that you cannot treat HTML pages as images in most cases. For instance, (in-line) ad + frames require an HTML page to be sent, or they won't display properly. + Forcing handle-as-image in this situation will not replace the + ad frame with an image, but lead to error messages. +

Example usage (sections):

+filter{shockwave-flash}     # Kill embedded Shockwave Flash objects
# Generic image extensions: +# +{+handle-as-image} +/.*\.(gif|jpg|jpeg|png|bmp|ico)$ + +# These don't look like images, but they're banners and should be +# blocked as images: +# +{+block{Nasty banners.} +handle-as-image} +nasty-banner-server.example.com/junk.cgi\?output=trash

8.5.20. hide-accept-language

Typical use:

Pretend to use different language settings.

Effect:

Deletes or replaces the "Accept-Language:" HTTP header in client requests. +

Type:

Parameterized.

Parameter:

Keyword: "block", or any user defined value. +

Notes:

Faking the browser's language settings can be useful to make a + foreign User-Agent set with + hide-user-agent -

However some sites with content in different languages check the + "Accept-Language:" to decide which one to take by default. + Sometimes it isn't possible to later switch to another language without + changing the "Accept-Language:" header first. +

Therefore it's a good idea to either only change the + "Accept-Language:" header to languages you understand, + or to languages that aren't wide spread. +

Before setting the "Accept-Language:" header + to a rare language, you should consider that it helps to + make your requests unique and thus easier to trace. + If you don't plan to change this header frequently, + you should stick to a common language. +

Example usage (section):

+filter{crude-parental}      # Kill all web pages that contain the words "sex" or "warez"
# Pretend to use Canadian language settings. +{+hide-accept-language{en-ca} \ ++hide-user-agent{Mozilla/5.0 (X11; U; OpenBSD i386; en-CA; rv:1.8.0.4) Gecko/20060628 Firefox/1.5.0.4} \ +} +/

8.5.9. handle-as-image8.5.21. hide-content-disposition

Typical use:

Mark URLs as belonging to images (so they'll be replaced by images if they get blocked)

Prevent download menus for content you prefer to view inside the browser.

Effect:

This action alone doesn't do anything noticeable. It just marks URLs as images. - If the block action also applies, - the presence or absence of this mark decides whether an HTML Deletes or replaces the "blocked" - page, or a replacement image (as determined by the set-image-blocker action) will be sent to the - client as a substitute for the blocked content. +>"Content-Disposition:" HTTP header set by some servers.

Type:

Boolean.

Parameterized.

Parameter:

N/A +> Keyword: "block", or any user defined value.

Notes:

The below generic example section is actually part of default.action. - It marks all URLs with well-known image file name extensions as images and should - be left intact. +> Some servers set the "Content-Disposition:" HTTP header for + documents they assume you want to save locally before viewing them. + The "Content-Disposition:" header contains the file name + the browser is supposed to use by default.

Users will probably only want to use the handle-as-image action in conjunction with - block, to block sources of banners, whose URLs don't - reflect the file type, like in the second example section. +> In most browsers that understand this header, it makes it impossible to + just view the document, without downloading it first, + even if it's just a simple text file or an image.

Note that you cannot treat HTML pages as images in most cases. For instance, (inline) ad - frames require an HTML page to be sent, or they won't display properly. - Forcing handle-as-image in this situation will not replace the - ad frame with an image, but lead to error messages. +> Removing the "Content-Disposition:" header helps + to prevent this annoyance, but some browsers additionally check the + "Content-Type:" header, before they decide if they can + display a document without saving it first. In these cases, you have + to change this header as well, before the browser stops displaying + download menus. +

It is also possible to change the server's file name suggestion + to another one, but in most cases it isn't worth the time to set + it up. +

This action will probably be removed in the future, + use server-header filters instead.

Example usage (sections):
Example usage:

# Generic image extensions:
-#
-{+handle-as-image}
-/.*\.(gif|jpg|jpeg|png|bmp|ico)$
-
-# These don't look like images, but they're banners and should be
-# blocked as images:
-#
-{+block +handle-as-image}
-some.nasty-banner-server.com/junk.cgi?output=trash
-
-# Banner source! Who cares if they also have non-image content?
-ad.doubleclick.net 
# Disarm the download link in Sourceforge's patch tracker +{ -filter \ + +content-type-overwrite{text/plain}\ + +hide-content-disposition{block} } + .sourceforge.net/tracker/download\.php

8.5.10. hide-forwarded-for-headers8.5.22. hide-if-modified-since

Typical use:

Improve privacy by hiding the true source of the request

Prevent yet another way to track the user's steps between sessions.

Effect:

Deletes any existing Deletes the "X-Forwarded-for:" HTTP header from client requests, - and prevents adding a new one. +>"If-Modified-Since:" HTTP client header or modifies its value.

Type:

Boolean.

Parameterized.

Parameter:

N/A +> Keyword: "block", or a user defined value that specifies a range of hours.

Notes:

It is fairly safe to leave this on. +> Removing this header is useful for filter testing, where you want to force a real + reload instead of getting status code "304", which would cause the + browser to use a cached copy of the page.

This action is scheduled for improvement: It should be able to generate forged +> Instead of removing the header, hide-if-modified-since can + also add or subtract a random amount of time to/from the header's value. + You specify a range of minutes where the random factor should be chosen from and Privoxy does the rest. A negative value means + subtracting, a positive value adding. +

Randomizing the value of the "X-Forwarded-for:" headers using random IP addresses from a specified network, - to make successive requests from the same client look like requests from a pool of different - users sharing the same proxy. +>"If-Modified-Since:" makes + it less likely that the server can use the time as a cookie replacement, + but you will run into caching problems if the random range is too high. +

It is a good idea to only use a small negative value and let + overwrite-last-modified + handle the greater changes. +

It is also recommended to use this action together with + crunch-if-none-match, + otherwise it's more or less pointless.

Example usage:
Example usage (section):

+hide-forwarded-for-headers
# Let the browser revalidate but make tracking based on the time less likely. +{+hide-if-modified-since{-60} \ + +overwrite-last-modified{randomize} \ + +crunch-if-none-match} +/
8.5.11. hide-from-header8.5.23. hide-from-header

8.5.12. hide-referrer8.5.24. hide-referrer

"conditional-block" to delete the header completely if the host has changed.

  • "conditional-forge" to forge the header if the host has changed.

  • "block" to delete the header completely.

    to delete the header unconditionally.

  • Notes:

    conditional-block is the only parameter, + that isn't easily detected in the server's log file. If it blocks the + referrer, the request will look like the visitor used a bookmark or + typed in the address directly. +

    Leaving the referrer unmodified for requests on the same host + allows the server owner to see the visitor's "forge" is the preferred option here, since some servers will - not send images back otherwise, in an attempt to prevent their valuable - content from being embedded elsewhere (and hence, without being surrounded - by their banners). +>"click path", + but in most cases she could also get that information by comparing + other parts of the log file: for example the User-Agent if it isn't + a very common one, or the user's IP address if it doesn't change between + different requests. +

    Always blocking the referrer, or using a custom one, can lead to + failures on servers that check the referrer before they answer any + requests, in an attempt to prevent their content from being + embedded or linked to elsewhere. +

    Both conditional-block and forge + will work with referrer checks, as long as content and valid referring page + are on the same host. Most of the time that's the case.

    - hide-referer is an alternate spelling of - hide-referrer and the two can be can be freely - substituted with each other. ("referrer" is the - correct English spelling, however the HTTP specification has a bug - it - requires it to be spelled as "referer".) -

    Example usage:
    8.5.13. hide-user-agent8.5.25. hide-user-agent

    Typical use:

    Conceal your type of browser and client operating system

    Try to conceal your type of browser and client operating system

    Effect:
    Parameter:

    Any user-defined string. +> Any user-defined string. +

    Notes:

    Warning

    This can lead to problems on web sites that depend on looking at this header in + order to customize their content for different browsers (which, by the + way, is NOT the right thing to do: good web sites + work browser-independently). +

    Using this action in multi-user setups or wherever different types of + browsers will access the same Privoxy is + not recommended. In single-user, single-browser + setups, you might use it to delete your OS version information from + the headers, because it is an invitation to exploit known bugs for your + OS. It is also occasionally useful to forge this in order to access + sites that won't let you in otherwise (though there may be a good + reason in some cases). Example of this: some MSN sites will not + let Mozilla enter, yet forging to a + Netscape 6.1 user-agent works just fine. + (Must be just a silly MS goof, I'm sure :-). +

    More information on known user-agent strings can be found at + http://www.user-agents.org/ + and + http://en.wikipedia.org/wiki/User_agent. +

    Example usage:

    +hide-user-agent{Netscape 6.1 (X11; I; Linux 2.4.18 i686)}
    +

  • 8.5.26. limit-connect

    Typical use:

    Prevent abuse of Privoxy as a TCP proxy relay or disable SSL for untrusted sites

    Effect:

    Specifies to which ports HTTP CONNECT requests are allowable. +

    Type:

    Parameterized.

    Parameter:

    A comma-separated list of ports or port ranges (the latter using dashes, with the minimum + defaulting to 0 and the maximum to 65K).

    Notes:

    Warning
    By default, i.e. if no limit-connect action applies, + Privoxy allows HTTP CONNECT requests to all + ports. Use limit-connect if fine-grained control + is desired for some or all destinations. +

    This breaks many web sites that depend on looking at this header in order - to customize their content for different browsers (which, by the - way, is NOT a smart way to do - that!). -

    The CONNECT methods exists in HTTP to allow access to secure websites + ("https://" URLs) through proxies. It works very simply: + the proxy connects to the server on the specified port, and then + short-circuits its connections to the client and to the remote server. + This means CONNECT-enabled proxies can be used as TCP relays very easily. +

    Using this action in multi-user setups or wherever different types of - browsers will access the same Privoxy is - not recommended. In single-user, single-browser - setups, you might use it to delete your OS version information from - the headers, because it is an invitation to exploit known bugs for your - OS. It is also occasionally useful to forge this in order to access - sites that won't let you in otherwise (though there may be a good - reason in some cases). Example of this: some MSN sites will not - let Mozilla enter, yet forging to a - relays HTTPS traffic without seeing + the decoded content. Websites can leverage this limitation to circumvent Netscape 6.1 user-agent works just fine. - (Must be just a silly MS goof, I'm sure :-). -

    This action is scheduled for improvement. -

    Privoxy's + filters. By specifying an invalid port range you can disable HTTPS entirely. +

    Example usage:
    Example usages:

    +hide-user-agent{Netscape 6.1 (X11; I; Linux 2.4.18 i686)}
    +limit-connect{443} # Port 443 is OK. ++limit-connect{80,443} # Ports 80 and 443 are OK. ++limit-connect{-3, 7, 20-100, 500-} # Ports less than 3, 7, 20 to 100 and above 500 are OK. ++limit-connect{-} # All ports are OK ++limit-connect{,} # No HTTPS/SSL traffic is allowed

    8.5.14. kill-popups8.5.27. prevent-compression

    Typical use:

    Eliminate those annoying pop-up windows

    Ensure that servers send the content uncompressed, so it can be + passed through filters. +

    Effect:

    While loading the document, replace JavaScript code that opens - pop-up windows with (syntactically neutral) dummy code on the fly. +> Removes the Accept-Encoding header which can be used to ask for compressed transfer.

    Notes:

    This action is easily confused with the built-in, hardwired More and more websites send their content compressed by default, which + is generally a good idea and saves bandwidth. But the filter - action, but there are important differences: For kill-popups, - the document need not be buffered, so it can be incrementally rendered while - downloading. But kill-popups doesn't catch as many pop-ups as +> and filter{popupsdeanimate-gifs} - does. + actions need access to the uncompressed data.

    Think of it as a fast and efficient replacement for a filter that you - can use if you don't want any filtering at all. Note that it doesn't make - sense to combine it with any filter action, - since as soon as one filter applies, - the whole document needs to be buffered anyway, which destroys the advantage of - the kill-popups action over its filter equivalent. +> When compiled with zlib support (available since Privoxy 3.0.7), content that should be + filtered is decompressed on-the-fly and you don't have to worry about this action. + If you are using an older Privoxy version, or one that hasn't been compiled with zlib + support, this action can be used to convince the server to send the content uncompressed.

    Killing all pop-ups is a dangerous business. Many shops and banks rely on - pop-ups to display forms, shopping carts etc, and killing only the unwanted pop-ups - would require artificial intelligence in Most text-based instances compress very well, the size is seldom decreased by less than 50%, + for markup-heavy instances like news feeds saving more than 90% of the original size isn't + unusual. +

    Not using compression will therefore slow down the transfer, and you should only + enable this action if you really need it. As of Privoxy. - If the only kind of pop-ups that you want to kill are exit consoles (those - really nasty windows that appear when you close an other - one), you might want to use +> 3.0.7 it's disabled in all + predefined action settings. +

    Note that some (rare) ill-configured sites don't handle requests for uncompressed + documents correctly. Broken PHP applications tend to send an empty document body, + some IIS versions only send the beginning of the content. If you enable filter{js-annoyances} - instead. +>prevent-compression per default, you might want to add + exceptions for those sites. See the example for how to do that.

    Example usage:
    Example usage (sections):

    +kill-popups
    # Selectively turn off compression, and enable a filter +# +{ +filter{tiny-textforms} +prevent-compression } +# Match only these sites + .google. + sourceforge.net + sf.net + +# Or instead, we could set a universal default: +# +{ +prevent-compression } + / # Match all sites + +# Then maybe make exceptions for broken sites: +# +{ -prevent-compression } +.compusa.com/

    +

    8.5.15. limit-connect8.5.28. overwrite-last-modified

    Typical use:

    Prevent abuse of Privoxy as a TCP proxy relay

    Prevent yet another way to track the user's steps between sessions.

    Effect:

    Specifies to which ports HTTP CONNECT requests are allowable. +> Deletes the "Last-Modified:" HTTP server header or modifies its value.

    Parameter:

    A comma-separated list of ports or port ranges (the latter using dashes, with the minimum - defaulting to 0 and the maximum to 65K). +> One of the keywords: "block", "reset-to-request-time" + and "randomize"

    Notes:

    By default, i.e. if no limit-connect action applies, +> Removing the "Last-Modified:" header is useful for filter + testing, where you want to force a real reload instead of getting status + code "304", which would cause the browser to reuse the old + version of the page. +

    The "randomize" option overwrites the value of the Privoxy only allows HTTP CONNECT - requests to port 443 (the standard, secure HTTPS port). Use +CLASS="QUOTE" +>"Last-Modified:" header with a randomly chosen time + between the original value and the current time. In theory the server + could send each document with a different "Last-Modified:" + header to track visits without using cookies. "Randomize" + makes it impossible and the browser can still revalidate cached documents. +

    "reset-to-request-time" overwrites the value of the + "Last-Modified:" header with the current time. You could use + this option together with limit-connect if more fine-grained control is desired - for some or all destinations. +>hide-if-modified-since + to further customize your random range.

    The CONNECT methods exists in HTTP to allow access to secure websites - ( The preferred parameter here is "https://" URLs) through proxies. It works very simply: - the proxy connects to the server on the specified port, and then - short-circuits its connections to the client and to the remote server. - This can be a big security hole, since CONNECT-enabled proxies can be - abused as TCP relays very easily. -

    "randomize". It is safe + to use, as long as the time settings are more or less correct. + If the server sets the "Last-Modified:" header to the time + of the request, the random range becomes zero and the value stays the same. + Therefore you should later randomize it a second time with + hided-if-modified-since, + just to be sure. +

    If you don't know what any of this means, there probably is no reason to - change this one, since the default is already very restrictive. -

    It is also recommended to use this action together with + crunch-if-none-match. +

    Example usages:
    Example usage:

    +limit-connect{443}                   # This is the default and need not be specified.
    -+limit-connect{80,443}                # Ports 80 and 443 are OK.
    -+limit-connect{-3, 7, 20-100, 500-}   # Ports less than 3, 7, 20 to 100 and above 500 are OK.
    -+limit-connect{-}                     # All ports are OK (gaping security hole!)
    # Let the browser revalidate without being tracked across sessions +{ +hide-if-modified-since{-60} \ + +overwrite-last-modified{randomize} \ + +crunch-if-none-match} +/

    8.5.16. prevent-compression8.5.29. redirect

    Typical use:

    Ensure that servers send the content uncompressed, so it can be - passed through filters +> Redirect requests to other sites.

    Effect:

    Adds a header to the request that asks for uncompressed transfer. +> Convinces the browser that the requested document has been moved + to another location and the browser should get it from there.

    Type:

    Boolean.

    Parameterized

    Parameter:

    N/A +> An absolute URL or a single pcrs command.

    Notes:

    More and more websites send their content compressed by default, which - is generally a good idea and saves bandwidth. But for the Requests to which this action applies are answered with a + HTTP redirect to URLs of your choosing. The new URL is + either provided as parameter, or derived by applying a + single pcrs command to the original URL. +

    This action will be ignored if you use it together with + filterblock, . + It can be combined with + deanimate-gifsfast-redirects{check-decoded-url} - and kill-popups actions to work, - Privoxy needs access to the uncompressed data. - Unfortunately, Privoxy can't yet(!) uncompress, filter, and - re-compress the content on the fly. So if you want to ensure that all websites, including - those that normally compress, can be filtered, you need to use this action. -

    This will slow down transfers from those websites, though. If you use any of the above-mentioned - actions, you will typically want to use prevent-compression in conjunction - with them. + to redirect to a decoded version of a rewritten URL.

    Note that some (rare) ill-configured sites don't handle requests for uncompressed - documents correctly (they send an empty document body). If you use prevent-compression - per default, you'll have to add exceptions for those sites. See the example for how to do that. +>

    Use this action carefully, make sure not to create redirection loops + and be aware that using your own redirects might make it + possible to fingerprint your requests. +

    In case of problems with your redirects, or simply to watch + them working, enable debug 128.

    Example usage (sections):
    Example usages:

    # Set default:
    -#
    -{+prevent-compression}
    -/ # Match all sites
    +># Replace example.com's style sheet with another one
    +{ +redirect{http://localhost/css-replacements/example.com.css} }
    + example.com/stylesheet\.css
     
    -# Make exceptions for ill sites:
    -#
    -{-prevent-compression}
    -www.debianhelp.org
    -www.pclinuxonline.com
    Privoxy) +{ +redirect{http://www.privoxy.org/user-manual/actions-file.html} } + a + +# Always use the expanded view for Undeadly.org articles +# (Note the $ at the end of the URL pattern to make sure +# the request for the rewritten URL isn't redirected as well) +{+redirect{s@$@&mode=expanded@}} +undeadly.org/cgi\?action=article&sid=\d*$ + +# Redirect Google search requests to MSN +{+redirect{s@^http://[^/]*/search\?q=([^&]*).*@http://search.msn.com/results.aspx?q=$1@}} +.google.com/search + +# Redirect MSN search requests to Yahoo +{+redirect{s@^http://[^/]*/results\.aspx\?q=([^&]*).*@http://search.yahoo.com/search?p=$1@}} +search.msn.com//results\.aspx\?q= + +# Redirect remote requests for this manual +# to the local version delivered by Privoxy +{+redirect{s@^http://www@http://config@}} +www.privoxy.org/user-manual/

    8.5.17. send-vanilla-wafer8.5.30. server-header-filter

    Typical use:

    Feed log analysis scripts with useless data. +> Rewrite or remove single server headers.

    Effect:

    Sends a cookie with each request stating that you do not accept any copyright - on cookies sent to you, and asking the site operator not to track you. +> All server headers to which this action applies are filtered on-the-fly + through the specified regular expression based substitutions.

    Type:

    Boolean.

    Parameterized.

    Parameter:

    N/A +> The name of a server-header filter, as defined in one of the + filter files.

    Notes:

    The vanilla wafer is a (relatively) unique header and could conceivably be used to track you. +> Server-header filters are applied to each header on its own, not to + all at once. This makes it easier to diagnose problems, but on the downside + you can't write filters that only change header x if header y's value is z. + You can do that by using tags though. +

    Server-header filters are executed after the other header actions have finished + and use their output as input.

    This action is rarely used and not enabled in the default configuration. +> Please refer to the filter file chapter + to learn which server-header filters are available by default, and how to + create your own.

    Example usage:
    Example usage (section):

    +send-vanilla-wafer
    {+server-header-filter{html-to-xml}} +example.org/xml-instance-that-is-delivered-as-html + +{+server-header-filter{xml-to-html}} +example.org/instance-that-is-delivered-as-xml-but-is-not +
    -

    8.5.18. send-wafer8.5.31. server-header-tagger

    Typical use:

    Send custom cookies or feed log analysis scripts with even more useless data. +> Enable or disable filters based on the Content-Type header.

    Effect:

    Sends a custom, user-defined cookie with each request. +> Server headers to which this action applies are filtered on-the-fly through + the specified regular expression based substitutions, the result is used as + tag.

    Type:

    Multi-value.

    Parameterized.

    Parameter:

    A string of the form "name=value" The name of a server-header tagger, as defined in one of the + filter files.

    Notes:

    Being multi-valued, multiple instances of this action can apply to the same request, - resulting in multiple cookies being sent. +> Server-header taggers are applied to each header on its own, + and as the header isn't modified, each tagger "sees" + the original. +

    Server-header taggers are executed before all other header actions + that modify server headers. Their tags can be used to control + all of the other server-header actions, the content filters + and the crunch actions (redirect + and block).

    This action is rarely used and not enabled in the default configuration. +> Obviously crunching based on tags created by server-header taggers + doesn't prevent the request from showing up in the server's log file.

    Example usage (section):

    {+send-wafer{UsingPrivoxy=true}}
    -my-internal-testing-server.void
    # Tag every request with the content type declared by the server +{+server-header-tagger{content-type}} +/ +
    -

    8.5.19. session-cookies-only8.5.32. session-cookies-only

    Allow only temporary "session" cookies (for the current browser session cookies (for the current + browser session only). +>).

    field from "Set-Cookie:" server headers. - Most browsers will not store such cookies permanently and forget them in between sessions. +> + server headers. Most browsers will not store such cookies permanently and + forget them in between sessions.

    It makes It makes no sense at all to use session-cookies-only field. If you use an exotic browser, you might want to try it out to be sure.

    This setting also has no effect on cookies that may have been stored + previously by the browser before starting Privoxy. + These would have to be removed manually. +

    Privoxy also uses + the content-cookies filter + to block some types of cookies. Content cookies are not effected by + session-cookies-only. +

    Example usage:
    8.5.20. set-image-blocker8.5.33. set-image-blocker

    Effect:

    This action alone doesn't do anything noticeable. If This action alone doesn't do anything noticeable. If both block and handle-as-image also apply, i.e. if the request is to be blocked as an image, - then the parameter of this action decides what will be sent as a replacement.

    target-url
    . You can redirect - to any image anywhere, even in your local filesystem (via "file:///" URL). +> URL. + (But note that not all browsers support redirecting to a local file system).

    A good application of redirects is to use special There is a third (advanced) type, called "auto". It is . It is NOT to be used in

    Redirect to the BSD devil: +> Redirect to the BSD daemon:

    8.5.21. Summary8.5.34. Summary

    Note that many of these actions have the potential to cause a page to @@ -3604,10 +6765,13 @@ CLASS="QUOTE" > and "}", but we , but we strongly recommend that you only use "a" sign, since they are merely textually expanded.

    Aliases can be used throughout the actions file, but they Aliases can be used throughout the actions file, but they must be defined in a special section at the top of the file! And there can only be one such section per actions file. Each actions file may have its own alias section, and the aliases defined in it are only visible @@ -3654,9 +6821,12 @@ CLASS="EMPHASIS" CLASS="QUOTE" >"shop", you can later change your policy on shops in - one place, and your changes will take effect everywhere in the actions file where the Privoxy.

    Now let's define some aliases...

    crunch-incoming-cookies +crunch-outgoing-cookies + -crunch-all-cookies = -crunch-incoming-cookies -crunch-outgoing-cookies + +block-as-image = +block{Blocked image.} +handle-as-image + allow-all-cookies = -crunch-all-cookies -session-cookies-only -filter{content-cookies} # These aliases define combinations of actions # that are useful for certain types of sites: # - fragile = -block -crunch-all-cookies -filter -fast-redirects -hide-referer -kill-popups - shop = -crunch-all-cookies -filter{popups} -kill-popups + fragile = -block -filter -crunch-all-cookies -fast-redirects -hide-referrer -prevent-compression + + shop = -crunch-all-cookies -filter{all-popups} # Short names for other aliases, for really lazy people ;-) # @@ -3739,7 +6942,8 @@ CLASS="SCREEN" {fragile} .office.microsoft.com .windowsupdate.microsoft.com - .nytimes.com + # Gmail is really mail.google.com, not gmail.com + mail.google.com # Shopping sites: # Allow cookies (for setting and retrieving your customer data) @@ -3747,11 +6951,11 @@ CLASS="SCREEN" {shop} .quietpc.com .worldpay.com # for quietpc.com - .scan.co.uk + mybank.example.com # These shops require pop-ups: # - {shop -kill-popups -filter{popups}} + {-filter{all-popups} -filter{unsolicited-popups}} .dabs.com .overclockers.co.uk and "fragile" are often used for +> are typically used for "problem" sites that require some actions to be disabled +> sites that require more than one action to be disabled in order to function properly.

    . Now, let's look at an example match-all.action, default.action and + and user.action - file and see how all these pieces come together:

    file and see how all these pieces come together:

    8.7.1. default.action8.7.1. match-all.action

    Every config file should start with a short comment stating its purpose:

    Remember all actions are disabled when matching starts, + so we have to explicitly enable the ones we want.

    While the match-all.action file only contains a + single section, it is probably the most important one. It has only one + pattern, "/", but this pattern + matches all URLs. Therefore, the set of + actions used in this "default" section will + be applied to all requests as a start. It can be partly or + wholly overridden by other actions files like default.action + and user.action, but it will still be largely responsible + for your overall browsing experience.

    Again, at the start of matching, all actions are disabled, so there is + no need to disable any actions here. (Remember: a "+" + preceding the action name enables the action, a "-" disables!). + Also note how this long line has been made more readable by splitting it into + multiple lines with line continuation.

    # Sample default.action file <developers@privoxy.org>
    { \ + +change-x-forwarded-for{block} \ + +hide-from-header{block} \ + +set-image-blocker{pattern} \ +} +/ # Match all URLs +

    Then, since this is the The default behavior is now set.

    8.7.2. default.action

    If you aren't a developer, there's no need for you to edit the + default.action file. It is maintained by + the Privoxy developers and if you disagree with some of the + sections, you should overrule them in your user.action.

    Understanding the default.action file, the -first section is a special section for internal use that you needn't -change or worry about:

    file can + help you with your user.action, though.

    The first section in this file is a special section for internal use + that prevents older Privoxy versions from reading the file:

    ########################################################################## # Settings -- Don't change! For internal Privoxy use ONLY. ########################################################################## - {{settings}} -for-privoxy-version=3.0

    After that comes the (optional) alias section. We'll use the example -section from the above After that comes the (optional) alias section. We'll use the example + section from the above chapter on aliases, -that also explains why and how aliases are used:

    Now come the regular sections, i.e. sets of actions, accompanied - by URL patterns to which they apply. Remember all actions - are disabled when matching starts, so we have to explicitly - enable the ones we want.

    The first regular section is probably the most important. It has only - one pattern, "/", but this pattern - matches all URLs.. Therefore, the - set of actions used in this "default" section will - be applied to all requests as a start. It can be partly or - wholly overridden by later matches further down this file, or in user.action, - but it will still be largely responsible for your overall browsing - experience.

    Again, at the start of matching, all actions are disabled, so there is - no real need to disable any actions here, but we will do that nonetheless, - to have a complete listing for your reference. (Remember: A "+"crunch-incoming-cookies +crunch-outgoing-cookies - preceding the action name enables the action, a "-" disables!). - Also note how this long line has been made more readable by splitting it into - multiple lines with line continuation.

    ##########################################################################
    -# "Defaults" section:
    -##########################################################################
    - { \
    - -add-header \
    - -block \
    - -crunch-incoming-cookies \
    - - -crunch-outgoing-cookies \
    - +deanimate-gifs \
    - -downgrade-http-version \
    - +fast-redirects \
    - +filter{html-annoyances} \
    - +filter{js-annoyances} \
    - -
    + +block-as-image      = +block{Blocked image.} +handle-as-image
    + mercy-for-cookies   = -crunch-all-cookies -session-cookies-only -filter{content-cookies} \
    - +filter{popups} \
    - +filter{webbugs} \
    - -filter{refresh-tags} \
    - -filter{fun} \
    - +filter{nimda} \
    - +filter{banners-by-size} \
    - -filter{shockwave-flash} \
    - -filter{crude-parental} \
    - -handle-as-image \
    - +hide-forwarded-for-headers \
    - +hide-from-header{block} \
    - +
    +
    + # These aliases define combinations of actions
    + # that are useful for certain types of sites:
    + #
    + fragile     = -block -filter -crunch-all-cookies -fast-redirects -hide-referrer{forge} \
    - -hide-user-agent \
    - -kill-popups \
    - -limit-connect \
    - +prevent-compression \
    - -send-vanilla-wafer \
    - -send-wafer \
    - +session-cookies-only \
    - +set-image-blocker{pattern} \
    - }
    - / # forward slash will match *all* potential URL patterns.
    hide-referrer + shop = -crunch-all-cookies -filter{all-popups}

    The default behavior is now set. Note that some actions, like not hiding - the user agent, are part of a "general policy" that applies - universally and won't get any exceptions defined later. Other choices, - like not blocking (which is understandably the - default!) need exceptions, i.e. we need to specify explicitly what we - want to block in later sections. - We will also want to make exceptions from our general pop-up-killing, - and use our defined aliases for that.

    The first of our specialized sections is concerned with "fragile"

    Then, there are sites which rely on pop-up windows (yuck!) to work. - Since we made pop-up-killing our default above, we need to make exceptions - now. Mozilla users, who - can turn on smart handling of unwanted pop-ups in their browsers, can - safely choose - -filter{popups} (and - -kill-popups) above - and hence don't need this section. Anyway, disabling an already disabled - action doesn't hurt, so we'll define our exceptions regardless of what was - chosen in the defaults section:

    # These sites require pop-ups too :( 
    -#
    -{ -kill-popups -filter{popups} }
    -.dabs.com
    -.overclockers.co.uk
    -.deutsche-bank-24.de

    The fast-redirects - action, which we enabled per default above, breaks some sites. So disable - it for popular sites where we know it misbehaves:

    match-all.action
    , + breaks some sites. So disable it for popular sites where we know it misbehaves:

    Privoxy knows which - URLs belong to images, so that if they are to be blocked, a substitute image can be sent, rather than an HTML page. Contacting the remote site to find out is not an option, since it would destroy the loading time advantage of banner blocking, and it - would feed the advertisers (in terms of money and - information). We can mark any URL as an image with the

    And then there are known banner sources. They often use scripts to generate the banners, so it won't be visible from the URL that the - request is for an image. Hence we block them and mark them as images in one go, with the help of our block-as-image+block-as-image alias defined above. (We could of course just as well use # Known ad generators: # -{ block-as-image } +{ +block-as-image } ar.atwola.com .ad.doubleclick.net .ad.*.doubleclick.net .a.yimg.com/(?:(?!/i/).)*$ .a[0-9].yimg.com/(?:(?!/i/).)*$ bs*.gsanet.com -bs*.einets.com .qkimg.netPrivoxy - is to block banners. A huge bunch of them are already "blocked" @@ -4382,7 +7480,7 @@ HREF="actions-file.html#BLOCK" > action to them.

    First comes a bunch of generic patterns, which do most of the work, by +> First comes many generic patterns, which do most of the work, by matching typical domain and path name components of banners. Then comes a list of individual patterns for specific sites, which is omitted here to keep the example short:

    +block
    +block{Banner ads.} } # Generic patterns: @@ -4420,7 +7518,7 @@ count*. >

    You wouldn't believe how many advertisers actually call their banner +> It's quite remarkable how many advertisers actually call their banner servers ads. e.g. catches "nasty-"nasty-ads.nasty-corp.com" as intended, but also "downlo"downloads.sourcefroge.net" or ""adsl.some-provider.net." So here come some well-known exceptions to the -block - applies, so (unless it matches again further down) it ends up with no } adv[io]*. # (for advogato.org and advice.*) adsl. # (has nothing to do with ads) +adobe. # (has nothing to do with ads either) ad[ud]*. # (adult.* and add.*) .edu # (universities don't host banners (yet!)) .*loads. # (downloads, uploads etc) @@ -4565,9 +7676,12 @@ HREF="actions-file.html#FILTER" >filter - disables all filters in one fell swoop!

    filter } -/.*cvs +/(.*/)?cvs +bugzilla. +developer. +wiki. .sourceforge.net The actual default.action is of course more +> is of course much more comprehensive, but we hope this example made clear how it works.

    8.7.2. user.action8.7.3. user.action

    So far we are painting with a broad brush by setting general policies, which would be a reasonable starting point for many people. Now, - you'd maybe want to be more specific and have customized rules that + you might want to be more specific and have customized rules that are more suitable to your personal habits and preferences. These would be for narrowly defined situations like your ISP or your bank, and should be placed in user.action is also a - safe place for your personal settings, since

    # My user.action file. <fred@foobar.com>
    # My user.action file. <fred@example.com>

    # (Re-)define aliases for this file:
    +># Aliases are local to the file they are defined in.
    +# (Re-)define aliases for this file:
     #
     {{alias}}
    +# 
    +# These aliases just save typing later, and the alias names should 
    +# be self explanatory.
    +#
    ++crunch-all-cookies = +crunch-incoming-cookies +crunch-outgoing-cookies
     -crunch-all-cookies = -crunch-incoming-cookies -crunch-outgoing-cookies
    -mercy-for-cookies   = -crunch-all-cookies -session-cookies-only
    -fragile     = -block -crunch-all-cookies -filter -fast-redirects -hide-referer -kill-popups
    -shop        = mercy-for-cookies -filter{popups} -kill-popups
    -allow-ads   = -block -filter{banners-by-size} # (see below)
    filter +-content-type-overwrite{text/plain} +-force-text-mode -hide-content-disposition -

    Say you have accounts on some sites that you visit regularly, and you don't want to have to log in manually each time. So you'd like to allow persistent cookies for these sites. The mercy-for-cookiesallow-all-cookies alias defined above does exactly - that, i.e. it disables crunching of cookies in any direction, and - processing of cookies to make them temporary.

    { mercy-for-cookies }
    -sunsolve.sun.com
    -slashdot.org
    -.yahoo.com
    -.msdn.microsoft.com
    -.redhat.com
    { allow-all-cookies } + sourceforge.net + .yahoo.com + .msdn.microsoft.com + .redhat.com

    Your bank needs popups and is allergic to some filter, but you don't - know which, so you disable them all:

    Your bank is allergic to some filter, but you don't know which, so you disable them all:

    { -filter -kill-popups } -.your-home-banking-site.com

    While browsing the web with Privoxy you - noticed some ads that sneaked through, but you were too lazy to - report them through our fine and easy feedback Some file types you may not want to filter for various reasons:

    # Technical documentation is likely to contain strings that might
    +# erroneously get altered by the JavaScript-oriented filters:
    +#
    +.tldp.org
    +/(.*/)?selfhtml/
    +
    +# And this stupid host sends streaming video with a wrong MIME type,
    +# so that Privoxy thinks it is getting HTML and starts filtering:
    +#
    +stupid-server.example.com/

    Example of a simple block action. Say you've + seen an ad on your favourite page on example.com that you want to get rid of. + You have right-clicked the image, selected "copy image location" - system, so you have added them here:

    { +block{} }
    section. Note that { +handle-as-image + } need not be specified, since all URLs ending in + .gif will be tagged as images by the general rules as set + in default.action anyway:

    { +block } -www.a-popular-site.com/some/unobvious/path -another.popular.site.net/more/junk/here/{Nasty ads.} } + www.example.com/nasty-ads/sponsor\.gif + another.example.net/more/junk/here/

    Note that, assuming the banners in the above example have regular image - extensions (most do), - The URLs of dynamically generated banners, especially from large banner + farms, often don't use the well-known image file name extensions, which + makes it impossible for Privoxy to guess + the file type just by looking at the URL. + You can use the +handle-as-image - need not be specified, since all URLs ending in these extensions will - already have been tagged as images in the relevant section of - default.action by now.

    +block-as-image alias defined above for + these cases. + Note that objects which match this rule but then turn out NOT to be an + image are typically rendered as a "broken image" icon by the + browser. Use cautiously.

    { +block-as-image }
    + .doubleclick.net
    + .fastclick.net
    + /Realmedia/ads/
    + ar.atwola.com/

    Then you noticed that the default configuration breaks Forbes Magazine, +> Now you noticed that the default configuration breaks Forbes Magazine, but you were too lazy to find out which action is the culprit, and you were again too lazy to give fragile alias on the site, and - -- whoa! -- it worked:

    whoa! -- it worked. The fragile + aliases disables those actions that are most likely to break a site. Also, + good for testing purposes to see if it is Privoxy + that is causing the problem or not. We later find other regular sites + that misbehave, and add those to our personalized list of troublemakers:

    { fragile }
    -.forbes.com
    default.filter
    , - but it is disabled in the distributed actions file. (My colleagues on the team just - don't have a sense of humour, that's why! ;-). So you'd like to turn it on in your private, + but it is disabled in the distributed actions file. + So you'd like to turn it on in your private, update-safe config, once and for all:

    filter{fun} } -/ # For ALL sites!
    "fun" filtering specified here.

    Finally, you might think about how your favourite free websites are +> You might also worry about how your favourite free websites are funded, and find that they rely on displaying banner advertisements to survive. So you might want to specifically allow banners for those sites that you feel provide value to you:

    { allow-ads }
    -.sourceforge.net
    -.slashdot.org
    -.osdn.net
    block
    +>, -filter{banners-by-size} - above.

    , and + -filter{banners-by-link} above.

    Invoke another alias here to force an over-ride of the MIME type application/x-sh which typically would open a download type + dialog. In my case, I want to look at the shell script, and then I can save + it should I choose to.

    { handle-as-text }
    + /.*\.sh$

    user.action is generally the best place to define + exceptions and additions to the default policies of + default.action. Some actions are safe to have their + default policies set here though. So let's set a default policy to have a + "blank" image as opposed to the checkerboard pattern for + ALL sites. "/" of course matches all URL + paths and patterns:

    { +set-image-blocker{blank} }
    +/ # ALL sites


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