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- <div class="SECT1">
- <h1 class="SECT1"><a name="APPENDIX" id="APPENDIX">14. Appendix</a></h1>
-
- <div class="SECT2">
- <h2 class="SECT2"><a name="REGEX" id="REGEX">14.1. Regular
- Expressions</a></h2>
-
- <p><span class="APPLICATION">Privoxy</span> uses Perl-style
- <span class="QUOTE">"regular expressions"</span> in its <a href=
- "actions-file.html">actions files</a> and <a href=
- "filter-file.html">filter file</a>, through the <a href=
- "http://www.pcre.org/" target="_top">PCRE</a> and <span class=
- "APPLICATION">PCRS</span> libraries.</p>
-
- <p>If you are reading this, you probably don't understand what
- <span class="QUOTE">"regular expressions"</span> are, or what they can
- do. So this will be a very brief introduction only. A full explanation
- would require a <a href="http://www.oreilly.com/catalog/regex/" target=
- "_top">book</a> ;-)</p>
-
- <p>Regular expressions provide a language to describe patterns that can
- be run against strings of characters (letter, numbers, etc), to see if
- they match the string or not. The patterns are themselves (sometimes
- complex) strings of literal characters, combined with wild-cards, and
- other special characters, called meta-characters. The <span class=
- "QUOTE">"meta-characters"</span> have special meanings and are used to
- build complex patterns to be matched against. Perl Compatible Regular
- Expressions are an especially convenient <span class=
- "QUOTE">"dialect"</span> of the regular expression language.</p>
-
- <p>To make a simple analogy, we do something similar when we use
- wild-card characters when listing files with the <b class=
- "COMMAND">dir</b> command in DOS. <tt class="LITERAL">*.*</tt> matches
- all filenames. The <span class="QUOTE">"special"</span> character here
- is the asterisk which matches any and all characters. We can be more
- specific and use <tt class="LITERAL">?</tt> to match just individual
- characters. So <span class="QUOTE">"dir file?.text"</span> would match
- <span class="QUOTE">"file1.txt"</span>, <span class=
- "QUOTE">"file2.txt"</span>, etc. We are pattern matching, using a
- similar technique to <span class="QUOTE">"regular
- expressions"</span>!</p>
-
- <p>Regular expressions do essentially the same thing, but are much,
- much more powerful. There are many more <span class="QUOTE">"special
- characters"</span> and ways of building complex patterns however. Let's
- look at a few of the common ones, and then some examples:</p>
-
- <table border="0">
- <tbody>
- <tr>
- <td><span class="emphasis"><i class="EMPHASIS">.</i></span> -
- Matches any single character, e.g. <span class=
- "QUOTE">"a"</span>, <span class="QUOTE">"A"</span>, <span class=
- "QUOTE">"4"</span>, <span class="QUOTE">":"</span>, or
- <span class="QUOTE">"@"</span>.</td>
- </tr>
- </tbody>
- </table>
-
- <table border="0">
- <tbody>
- <tr>
- <td><span class="emphasis"><i class="EMPHASIS">?</i></span> - The
- preceding character or expression is matched ZERO or ONE times.
- Either/or.</td>
- </tr>
- </tbody>
- </table>
-
- <table border="0">
- <tbody>
- <tr>
- <td><span class="emphasis"><i class="EMPHASIS">+</i></span> - The
- preceding character or expression is matched ONE or MORE
- times.</td>
- </tr>
- </tbody>
- </table>
-
- <table border="0">
- <tbody>
- <tr>
- <td><span class="emphasis"><i class="EMPHASIS">*</i></span> - The
- preceding character or expression is matched ZERO or MORE
- times.</td>
- </tr>
- </tbody>
- </table>
-
- <table border="0">
- <tbody>
- <tr>
- <td><span class="emphasis"><i class="EMPHASIS">\</i></span> - The
- <span class="QUOTE">"escape"</span> character denotes that the
- following character should be taken literally. This is used where
- one of the special characters (e.g. <span class=
- "QUOTE">"."</span>) needs to be taken literally and not as a
- special meta-character. Example: <span class=
- "QUOTE">"example\.com"</span>, makes sure the period is
- recognized only as a period (and not expanded to its
- meta-character meaning of any single character).</td>
- </tr>
- </tbody>
- </table>
-
- <table border="0">
- <tbody>
- <tr>
- <td><span class="emphasis"><i class="EMPHASIS">[ ]</i></span> -
- Characters enclosed in brackets will be matched if any of the
- enclosed characters are encountered. For instance, <span class=
- "QUOTE">"[0-9]"</span> matches any numeric digit (zero through
- nine). As an example, we can combine this with <span class=
- "QUOTE">"+"</span> to match any digit one of more times:
- <span class="QUOTE">"[0-9]+"</span>.</td>
- </tr>
- </tbody>
- </table>
-
- <table border="0">
- <tbody>
- <tr>
- <td><span class="emphasis"><i class="EMPHASIS">( )</i></span> -
- parentheses are used to group a sub-expression, or multiple
- sub-expressions.</td>
- </tr>
- </tbody>
- </table>
-
- <table border="0">
- <tbody>
- <tr>
- <td><span class="emphasis"><i class="EMPHASIS">|</i></span> - The
- <span class="QUOTE">"bar"</span> character works like an
- <span class="QUOTE">"or"</span> conditional statement. A match is
- successful if the sub-expression on either side of <span class=
- "QUOTE">"|"</span> matches. As an example: <span class=
- "QUOTE">"/(this|that) example/"</span> uses grouping and the bar
- character and would match either <span class="QUOTE">"this
- example"</span> or <span class="QUOTE">"that example"</span>, and
- nothing else.</td>
- </tr>
- </tbody>
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-
- <p>These are just some of the ones you are likely to use when matching
- URLs with <span class="APPLICATION">Privoxy</span>, and is a long way
- from a definitive list. This is enough to get us started with a few
- simple examples which may be more illuminating:</p>
-
- <p><span class="emphasis"><i class="EMPHASIS"><tt class=
- "LITERAL">/.*/banners/.*</tt></i></span> - A simple example that uses
- the common combination of <span class="QUOTE">"."</span> and
- <span class="QUOTE">"*"</span> to denote any character, zero or more
- times. In other words, any string at all. So we start with a literal
- forward slash, then our regular expression pattern (<span class=
- "QUOTE">".*"</span>) another literal forward slash, the string
- <span class="QUOTE">"banners"</span>, another forward slash, and lastly
- another <span class="QUOTE">".*"</span>. We are building a directory
- path here. This will match any file with the path that has a directory
- named <span class="QUOTE">"banners"</span> in it. The <span class=
- "QUOTE">".*"</span> matches any characters, and this could conceivably
- be more forward slashes, so it might expand into a much longer looking
- path. For example, this could match: <span class=
- "QUOTE">"/eye/hate/spammers/banners/annoy_me_please.gif"</span>, or
- just <span class="QUOTE">"/banners/annoying.html"</span>, or almost an
- infinite number of other possible combinations, just so it has
- <span class="QUOTE">"banners"</span> in the path somewhere.</p>
-
- <p>And now something a little more complex:</p>
-
- <p><span class="emphasis"><i class="EMPHASIS"><tt class=
- "LITERAL">/.*/adv((er)?ts?|ertis(ing|ements?))?/</tt></i></span> - We
- have several literal forward slashes again (<span class=
- "QUOTE">"/"</span>), so we are building another expression that is a
- file path statement. We have another <span class="QUOTE">".*"</span>,
- so we are matching against any conceivable sub-path, just so it matches
- our expression. The only true literal that <span class=
- "emphasis"><i class="EMPHASIS">must match</i></span> our pattern is
- <span class="APPLICATION">adv</span>, together with the forward
- slashes. What comes after the <span class="QUOTE">"adv"</span> string
- is the interesting part.</p>
-
- <p>Remember the <span class="QUOTE">"?"</span> means the preceding
- expression (either a literal character or anything grouped with
- <span class="QUOTE">"(...)"</span> in this case) can exist or not,
- since this means either zero or one match. So <span class=
- "QUOTE">"((er)?ts?|ertis(ing|ements?))"</span> is optional, as are the
- individual sub-expressions: <span class="QUOTE">"(er)"</span>,
- <span class="QUOTE">"(ing|ements?)"</span>, and the <span class=
- "QUOTE">"s"</span>. The <span class="QUOTE">"|"</span> means
- <span class="QUOTE">"or"</span>. We have two of those. For instance,
- <span class="QUOTE">"(ing|ements?)"</span>, can expand to match either
- <span class="QUOTE">"ing"</span> <span class="emphasis"><i class=
- "EMPHASIS">OR</i></span> <span class="QUOTE">"ements?"</span>. What is
- being done here, is an attempt at matching as many variations of
- <span class="QUOTE">"advertisement"</span>, and similar, as possible.
- So this would expand to match just <span class="QUOTE">"adv"</span>, or
- <span class="QUOTE">"advert"</span>, or <span class=
- "QUOTE">"adverts"</span>, or <span class="QUOTE">"advertising"</span>,
- or <span class="QUOTE">"advertisement"</span>, or <span class=
- "QUOTE">"advertisements"</span>. You get the idea. But it would not
- match <span class="QUOTE">"advertizements"</span> (with a <span class=
- "QUOTE">"z"</span>). We could fix that by changing our regular
- expression to: <span class=
- "QUOTE">"/.*/adv((er)?ts?|erti(s|z)(ing|ements?))?/"</span>, which
- would then match either spelling.</p>
-
- <p><span class="emphasis"><i class="EMPHASIS"><tt class=
- "LITERAL">/.*/advert[0-9]+\.(gif|jpe?g)</tt></i></span> - Again another
- path statement with forward slashes. Anything in the square brackets
- <span class="QUOTE">"[ ]"</span> can be matched. This is using
- <span class="QUOTE">"0-9"</span> as a shorthand expression to mean any
- digit one through nine. It is the same as saying <span class=
- "QUOTE">"0123456789"</span>. So any digit matches. The <span class=
- "QUOTE">"+"</span> means one or more of the preceding expression must
- be included. The preceding expression here is what is in the square
- brackets -- in this case, any digit one through nine. Then, at the end,
- we have a grouping: <span class="QUOTE">"(gif|jpe?g)"</span>. This
- includes a <span class="QUOTE">"|"</span>, so this needs to match the
- expression on either side of that bar character also. A simple
- <span class="QUOTE">"gif"</span> on one side, and the other side will
- in turn match either <span class="QUOTE">"jpeg"</span> or <span class=
- "QUOTE">"jpg"</span>, since the <span class="QUOTE">"?"</span> means
- the letter <span class="QUOTE">"e"</span> is optional and can be
- matched once or not at all. So we are building an expression here to
- match image GIF or JPEG type image file. It must include the literal
- string <span class="QUOTE">"advert"</span>, then one or more digits,
- and a <span class="QUOTE">"."</span> (which is now a literal, and not a
- special character, since it is escaped with <span class=
- "QUOTE">"\"</span>), and lastly either <span class=
- "QUOTE">"gif"</span>, or <span class="QUOTE">"jpeg"</span>, or
- <span class="QUOTE">"jpg"</span>. Some possible matches would include:
- <span class="QUOTE">"//advert1.jpg"</span>, <span class=
- "QUOTE">"/nasty/ads/advert1234.gif"</span>, <span class=
- "QUOTE">"/banners/from/hell/advert99.jpg"</span>. It would not match
- <span class="QUOTE">"advert1.gif"</span> (no leading slash), or
- <span class="QUOTE">"/adverts232.jpg"</span> (the expression does not
- include an <span class="QUOTE">"s"</span>), or <span class=
- "QUOTE">"/advert1.jsp"</span> (<span class="QUOTE">"jsp"</span> is not
- in the expression anywhere).</p>
-
- <p>We are barely scratching the surface of regular expressions here so
- that you can understand the default <span class=
- "APPLICATION">Privoxy</span> configuration files, and maybe use this
- knowledge to customize your own installation. There is much, much more
- that can be done with regular expressions. Now that you know enough to
- get started, you can learn more on your own :/</p>
-
- <p>More reading on Perl Compatible Regular expressions: <a href=
- "http://perldoc.perl.org/perlre.html" target=
- "_top">http://perldoc.perl.org/perlre.html</a></p>
-
- <p>For information on regular expression based substitutions and their
- applications in filters, please see the <a href=
- "filter-file.html">filter file tutorial</a> in this manual.</p>
+ <hr align="LEFT" width="100%">
</div>
-
- <div class="SECT2">
- <h2 class="SECT2"><a name="INTERNAL-PAGES" id="INTERNAL-PAGES">14.2.
- Privoxy's Internal Pages</a></h2>
-
- <p>Since <span class="APPLICATION">Privoxy</span> proxies each
- requested web page, it is easy for <span class=
- "APPLICATION">Privoxy</span> to trap certain special URLs. In this way,
- we can talk directly to <span class="APPLICATION">Privoxy</span>, and
- see how it is configured, see how our rules are being applied, change
- these rules and other configuration options, and even turn <span class=
- "APPLICATION">Privoxy's</span> filtering off, all with a web
- browser.</p>
-
- <p>The URLs listed below are the special ones that allow direct access
- to <span class="APPLICATION">Privoxy</span>. Of course, <span class=
- "APPLICATION">Privoxy</span> must be running to access these. If not,
- you will get a friendly error message. Internet access is not necessary
- either.</p>
-
- <ul>
- <li>
- <p>Privoxy main page:</p><a name="AEN5923" id="AEN5923"></a>
-
- <blockquote class="BLOCKQUOTE">
- <p><a href="http://config.privoxy.org/" target=
- "_top">http://config.privoxy.org/</a></p>
- </blockquote>
-
- <p>There is a shortcut: <a href="http://p.p/" target=
- "_top">http://p.p/</a> (But it doesn't provide a fall-back to a
- real page, in case the request is not sent through <span class=
- "APPLICATION">Privoxy</span>)</p>
- </li>
-
- <li>
- <p>Show information about the current configuration, including
- viewing and editing of actions files:</p><a name="AEN5931" id=
- "AEN5931"></a>
-
- <blockquote class="BLOCKQUOTE">
- <p><a href="http://config.privoxy.org/show-status" target=
- "_top">http://config.privoxy.org/show-status</a></p>
- </blockquote>
- </li>
-
- <li>
- <p>Show the source code version numbers:</p><a name="AEN5936" id=
- "AEN5936"></a>
-
- <blockquote class="BLOCKQUOTE">
- <p><a href="http://config.privoxy.org/show-version" target=
- "_top">http://config.privoxy.org/show-version</a></p>
- </blockquote>
- </li>
-
- <li>
- <p>Show the browser's request headers:</p><a name="AEN5941" id=
- "AEN5941"></a>
-
- <blockquote class="BLOCKQUOTE">
- <p><a href="http://config.privoxy.org/show-request" target=
- "_top">http://config.privoxy.org/show-request</a></p>
- </blockquote>
- </li>
-
- <li>
- <p>Show which actions apply to a URL and why:</p><a name="AEN5946"
- id="AEN5946"></a>
-
- <blockquote class="BLOCKQUOTE">
- <p><a href="http://config.privoxy.org/show-url-info" target=
- "_top">http://config.privoxy.org/show-url-info</a></p>
- </blockquote>
- </li>
-
- <li>
- <p>Toggle Privoxy on or off. This feature can be turned off/on in
- the main <tt class="FILENAME">config</tt> file. When toggled
- <span class="QUOTE">"off"</span>, <span class=
- "QUOTE">"Privoxy"</span> continues to run, but only as a
- pass-through proxy, with no actions taking place:</p><a name=
- "AEN5954" id="AEN5954"></a>
-
- <blockquote class="BLOCKQUOTE">
- <p><a href="http://config.privoxy.org/toggle" target=
- "_top">http://config.privoxy.org/toggle</a></p>
- </blockquote>
-
- <p>Short cuts. Turn off, then on:</p><a name="AEN5958" id=
- "AEN5958"></a>
-
- <blockquote class="BLOCKQUOTE">
- <p><a href="http://config.privoxy.org/toggle?set=disable" target=
- "_top">http://config.privoxy.org/toggle?set=disable</a></p>
- </blockquote><a name="AEN5961" id="AEN5961"></a>
-
- <blockquote class="BLOCKQUOTE">
- <p><a href="http://config.privoxy.org/toggle?set=enable" target=
- "_top">http://config.privoxy.org/toggle?set=enable</a></p>
- </blockquote>
- </li>
- </ul>
- </div>
-
- <div class="SECT2">
- <h2 class="SECT2"><a name="CHAIN" id="CHAIN">14.3. Chain of
- Events</a></h2>
-
- <p>Let's take a quick look at how some of <span class=
- "APPLICATION">Privoxy's</span> core features are triggered, and the
- ensuing sequence of events when a web page is requested by your
- browser:</p>
-
- <ul>
- <li>
- <p>First, your web browser requests a web page. The browser knows
- to send the request to <span class="APPLICATION">Privoxy</span>,
- which will in turn, relay the request to the remote web server
- after passing the following tests:</p>
- </li>
-
- <li>
- <p><span class="APPLICATION">Privoxy</span> traps any request for
- its own internal CGI pages (e.g <a href="http://p.p/" target=
- "_top">http://p.p/</a>) and sends the CGI page back to the
- browser.</p>
- </li>
-
- <li>
- <p>Next, <span class="APPLICATION">Privoxy</span> checks to see if
- the URL matches any <a href="actions-file.html#BLOCK"><span class=
- "QUOTE">"+block"</span></a> patterns. If so, the URL is then
- blocked, and the remote web server will not be contacted. <a href=
- "actions-file.html#HANDLE-AS-IMAGE"><span class=
- "QUOTE">"+handle-as-image"</span></a> and <a href=
- "actions-file.html#HANDLE-AS-EMPTY-DOCUMENT"><span class=
- "QUOTE">"+handle-as-empty-document"</span></a> are then checked,
- and if there is no match, an HTML <span class=
- "QUOTE">"BLOCKED"</span> page is sent back to the browser.
- Otherwise, if it does match, an image is returned for the former,
- and an empty text document for the latter. The type of image would
- depend on the setting of <a href=
- "actions-file.html#SET-IMAGE-BLOCKER"><span class=
- "QUOTE">"+set-image-blocker"</span></a> (blank, checkerboard
- pattern, or an HTTP redirect to an image elsewhere).</p>
- </li>
-
- <li>
- <p>Untrusted URLs are blocked. If URLs are being added to the
- <tt class="FILENAME">trust</tt> file, then that is done.</p>
- </li>
-
- <li>
- <p>If the URL pattern matches the <a href=
- "actions-file.html#FAST-REDIRECTS"><span class=
- "QUOTE">"+fast-redirects"</span></a> action, it is then processed.
- Unwanted parts of the requested URL are stripped.</p>
- </li>
-
- <li>
- <p>Now the rest of the client browser's request headers are
- processed. If any of these match any of the relevant actions (e.g.
- <a href="actions-file.html#HIDE-USER-AGENT"><span class=
- "QUOTE">"+hide-user-agent"</span></a>, etc.), headers are
- suppressed or forged as determined by these actions and their
- parameters.</p>
- </li>
-
- <li>
- <p>Now the web server starts sending its response back (i.e.
- typically a web page).</p>
- </li>
-
- <li>
- <p>First, the server headers are read and processed to determine,
- among other things, the MIME type (document type) and encoding. The
- headers are then filtered as determined by the <a href=
- "actions-file.html#CRUNCH-INCOMING-COOKIES"><span class=
- "QUOTE">"+crunch-incoming-cookies"</span></a>, <a href=
- "actions-file.html#SESSION-COOKIES-ONLY"><span class=
- "QUOTE">"+session-cookies-only"</span></a>, and <a href=
- "actions-file.html#DOWNGRADE-HTTP-VERSION"><span class=
- "QUOTE">"+downgrade-http-version"</span></a> actions.</p>
- </li>
-
- <li>
- <p>If any <a href="actions-file.html#FILTER"><span class=
- "QUOTE">"+filter"</span></a> action or <a href=
- "actions-file.html#DEANIMATE-GIFS"><span class=
- "QUOTE">"+deanimate-gifs"</span></a> action applies (and the
- document type fits the action), the rest of the page is read into
- memory (up to a configurable limit). Then the filter rules (from
- <tt class="FILENAME">default.filter</tt> and any other filter
- files) are processed against the buffered content. Filters are
- applied in the order they are specified in one of the filter files.
- Animated GIFs, if present, are reduced to either the first or last
- frame, depending on the action setting.The entire page, which is
- now filtered, is then sent by <span class=
- "APPLICATION">Privoxy</span> back to your browser.</p>
-
- <p>If neither a <a href="actions-file.html#FILTER"><span class=
- "QUOTE">"+filter"</span></a> action or <a href=
- "actions-file.html#DEANIMATE-GIFS"><span class=
- "QUOTE">"+deanimate-gifs"</span></a> matches, then <span class=
- "APPLICATION">Privoxy</span> passes the raw data through to the
- client browser as it becomes available.</p>
- </li>
-
- <li>
- <p>As the browser receives the now (possibly filtered) page
- content, it reads and then requests any URLs that may be embedded
- within the page source, e.g. ad images, stylesheets, JavaScript,
- other HTML documents (e.g. frames), sounds, etc. For each of these
- objects, the browser issues a separate request (this is easily
- viewable in <span class="APPLICATION">Privoxy's</span> logs). And
- each such request is in turn processed just as above. Note that a
- complex web page will have many, many such embedded URLs. If these
- secondary requests are to a different server, then quite possibly a
- very differing set of actions is triggered.</p>
- </li>
- </ul>
-
- <p>NOTE: This is somewhat of a simplistic overview of what happens with
- each URL request. For the sake of brevity and simplicity, we have
- focused on <span class="APPLICATION">Privoxy's</span> core features
- only.</p>
- </div>
-
- <div class="SECT2">
- <h2 class="SECT2"><a name="ACTIONSANAT" id="ACTIONSANAT">14.4.
- Troubleshooting: Anatomy of an Action</a></h2>
-
- <p>The way <span class="APPLICATION">Privoxy</span> applies <a href=
- "actions-file.html#ACTIONS">actions</a> and <a href=
- "actions-file.html#FILTER">filters</a> to any given URL can be complex,
- and not always so easy to understand what is happening. And sometimes
- we need to be able to <span class="emphasis"><i class=
- "EMPHASIS">see</i></span> just what <span class=
- "APPLICATION">Privoxy</span> is doing. Especially, if something
- <span class="APPLICATION">Privoxy</span> is doing is causing us a
- problem inadvertently. It can be a little daunting to look at the
- actions and filters files themselves, since they tend to be filled with
- <a href="appendix.html#REGEX">regular expressions</a> whose
- consequences are not always so obvious.</p>
-
- <p>One quick test to see if <span class="APPLICATION">Privoxy</span> is
- causing a problem or not, is to disable it temporarily. This should be
- the first troubleshooting step (be sure to flush caches afterward!).
- Looking at the logs is a good idea too. (Note that both the toggle
- feature and logging are enabled via <tt class="FILENAME">config</tt>
- file settings, and may need to be turned <span class=
- "QUOTE">"on"</span>.)</p>
-
- <p>Another easy troubleshooting step to try is if you have done any
- customization of your installation, revert back to the installed
- defaults and see if that helps. There are times the developers get
- complaints about one thing or another, and the problem is more related
- to a customized configuration issue.</p>
-
- <p><span class="APPLICATION">Privoxy</span> also provides the <a href=
- "http://config.privoxy.org/show-url-info" target=
- "_top">http://config.privoxy.org/show-url-info</a> page that can show
- us very specifically how <span class="APPLICATION">actions</span> are
- being applied to any given URL. This is a big help for
- troubleshooting.</p>
-
- <p>First, enter one URL (or partial URL) at the prompt, and then
- <span class="APPLICATION">Privoxy</span> will tell us how the current
- configuration will handle it. This will not help with filtering effects
- (i.e. the <a href="actions-file.html#FILTER"><span class=
- "QUOTE">"+filter"</span></a> action) from one of the filter files since
- this is handled very differently and not so easy to trap! It also will
- not tell you about any other URLs that may be embedded within the URL
- you are testing. For instance, images such as ads are expressed as URLs
- within the raw page source of HTML pages. So you will only get info for
- the actual URL that is pasted into the prompt area -- not any sub-URLs.
- If you want to know about embedded URLs like ads, you will have to dig
- those out of the HTML source. Use your browser's <span class=
- "QUOTE">"View Page Source"</span> option for this. Or right click on
- the ad, and grab the URL.</p>
-
- <p>Let's try an example, <a href="http://google.com" target=
- "_top">google.com</a>, and look at it one section at a time in a sample
- configuration (your real configuration may vary):</p>
-
- <table border="0" bgcolor="#E0E0E0" width="100%">
- <tr>
- <td>
- <pre class="SCREEN">
+ <div class="SECT1">
+ <h1 class="SECT1">
+ <a name="APPENDIX">14. Appendix</a>
+ </h1>
+ <div class="SECT2">
+ <h2 class="SECT2">
+ <a name="REGEX">14.1. Regular Expressions</a>
+ </h2>
+ <p>
+ <span class="APPLICATION">Privoxy</span> uses Perl-style <span
+ class="QUOTE">"regular expressions"</span> in its <a href=
+ "actions-file.html">actions files</a> and <a href=
+ "filter-file.html">filter file</a>, through the <a href=
+ "http://www.pcre.org/" target="_top">PCRE</a> and <span class=
+ "APPLICATION">PCRS</span> libraries.
+ </p>
+ <p>
+ If you are reading this, you probably don't understand what <span
+ class="QUOTE">"regular expressions"</span> are, or what they can
+ do. So this will be a very brief introduction only. A full
+ explanation would require a <a href=
+ "http://www.oreilly.com/catalog/regex/" target="_top">book</a> ;-)
+ </p>
+ <p>
+ Regular expressions provide a language to describe patterns that
+ can be run against strings of characters (letter, numbers, etc), to
+ see if they match the string or not. The patterns are themselves
+ (sometimes complex) strings of literal characters, combined with
+ wild-cards, and other special characters, called meta-characters.
+ The <span class="QUOTE">"meta-characters"</span> have special
+ meanings and are used to build complex patterns to be matched
+ against. Perl Compatible Regular Expressions are an especially
+ convenient <span class="QUOTE">"dialect"</span> of the regular
+ expression language.
+ </p>
+ <p>
+ To make a simple analogy, we do something similar when we use
+ wild-card characters when listing files with the <b class=
+ "COMMAND">dir</b> command in DOS. <tt class="LITERAL">*.*</tt>
+ matches all filenames. The <span class="QUOTE">"special"</span>
+ character here is the asterisk which matches any and all
+ characters. We can be more specific and use <tt class=
+ "LITERAL">?</tt> to match just individual characters. So <span
+ class="QUOTE">"dir file?.text"</span> would match <span class=
+ "QUOTE">"file1.txt"</span>, <span class="QUOTE">"file2.txt"</span>,
+ etc. We are pattern matching, using a similar technique to <span
+ class="QUOTE">"regular expressions"</span>!
+ </p>
+ <p>
+ Regular expressions do essentially the same thing, but are much,
+ much more powerful. There are many more <span class=
+ "QUOTE">"special characters"</span> and ways of building complex
+ patterns however. Let's look at a few of the common ones, and then
+ some examples:
+ </p>
+ <table border="0">
+ <tbody>
+ <tr>
+ <td>
+ <span class="emphasis"><i class="EMPHASIS">.</i></span> -
+ Matches any single character, e.g. <span class=
+ "QUOTE">"a"</span>, <span class="QUOTE">"A"</span>, <span
+ class="QUOTE">"4"</span>, <span class="QUOTE">":"</span>, or
+ <span class="QUOTE">"@"</span>.
+ </td>
+ </tr>
+ </tbody>
+ </table>
+
+ <table border="0">
+ <tbody>
+ <tr>
+ <td>
+ <span class="emphasis"><i class="EMPHASIS">?</i></span> - The
+ preceding character or expression is matched ZERO or ONE
+ times. Either/or.
+ </td>
+ </tr>
+ </tbody>
+ </table>
+
+ <table border="0">
+ <tbody>
+ <tr>
+ <td>
+ <span class="emphasis"><i class="EMPHASIS">+</i></span> - The
+ preceding character or expression is matched ONE or MORE
+ times.
+ </td>
+ </tr>
+ </tbody>
+ </table>
+
+ <table border="0">
+ <tbody>
+ <tr>
+ <td>
+ <span class="emphasis"><i class="EMPHASIS">*</i></span> - The
+ preceding character or expression is matched ZERO or MORE
+ times.
+ </td>
+ </tr>
+ </tbody>
+ </table>
+
+ <table border="0">
+ <tbody>
+ <tr>
+ <td>
+ <span class="emphasis"><i class="EMPHASIS">\</i></span> - The
+ <span class="QUOTE">"escape"</span> character denotes that
+ the following character should be taken literally. This is
+ used where one of the special characters (e.g. <span class=
+ "QUOTE">"."</span>) needs to be taken literally and not as a
+ special meta-character. Example: <span class=
+ "QUOTE">"example\.com"</span>, makes sure the period is
+ recognized only as a period (and not expanded to its
+ meta-character meaning of any single character).
+ </td>
+ </tr>
+ </tbody>
+ </table>
+
+ <table border="0">
+ <tbody>
+ <tr>
+ <td>
+ <span class="emphasis"><i class="EMPHASIS">[ ]</i></span> -
+ Characters enclosed in brackets will be matched if any of the
+ enclosed characters are encountered. For instance, <span
+ class="QUOTE">"[0-9]"</span> matches any numeric digit (zero
+ through nine). As an example, we can combine this with <span
+ class="QUOTE">"+"</span> to match any digit one of more
+ times: <span class="QUOTE">"[0-9]+"</span>.
+ </td>
+ </tr>
+ </tbody>
+ </table>
+
+ <table border="0">
+ <tbody>
+ <tr>
+ <td>
+ <span class="emphasis"><i class="EMPHASIS">( )</i></span> -
+ parentheses are used to group a sub-expression, or multiple
+ sub-expressions.
+ </td>
+ </tr>
+ </tbody>
+ </table>
+
+ <table border="0">
+ <tbody>
+ <tr>
+ <td>
+ <span class="emphasis"><i class="EMPHASIS">|</i></span> - The
+ <span class="QUOTE">"bar"</span> character works like an
+ <span class="QUOTE">"or"</span> conditional statement. A
+ match is successful if the sub-expression on either side of
+ <span class="QUOTE">"|"</span> matches. As an example: <span
+ class="QUOTE">"/(this|that) example/"</span> uses grouping
+ and the bar character and would match either <span class=
+ "QUOTE">"this example"</span> or <span class="QUOTE">"that
+ example"</span>, and nothing else.
+ </td>
+ </tr>
+ </tbody>
+ </table>
+
+ <p>
+ These are just some of the ones you are likely to use when matching
+ URLs with <span class="APPLICATION">Privoxy</span>, and is a long
+ way from a definitive list. This is enough to get us started with a
+ few simple examples which may be more illuminating:
+ </p>
+ <p>
+ <span class="emphasis"><i class="EMPHASIS"><tt class=
+ "LITERAL">/.*/banners/.*</tt></i></span> - A simple example that
+ uses the common combination of <span class="QUOTE">"."</span> and
+ <span class="QUOTE">"*"</span> to denote any character, zero or
+ more times. In other words, any string at all. So we start with a
+ literal forward slash, then our regular expression pattern (<span
+ class="QUOTE">".*"</span>) another literal forward slash, the
+ string <span class="QUOTE">"banners"</span>, another forward slash,
+ and lastly another <span class="QUOTE">".*"</span>. We are building
+ a directory path here. This will match any file with the path that
+ has a directory named <span class="QUOTE">"banners"</span> in it.
+ The <span class="QUOTE">".*"</span> matches any characters, and
+ this could conceivably be more forward slashes, so it might expand
+ into a much longer looking path. For example, this could match:
+ <span class=
+ "QUOTE">"/eye/hate/spammers/banners/annoy_me_please.gif"</span>, or
+ just <span class="QUOTE">"/banners/annoying.html"</span>, or almost
+ an infinite number of other possible combinations, just so it has
+ <span class="QUOTE">"banners"</span> in the path somewhere.
+ </p>
+ <p>
+ And now something a little more complex:
+ </p>
+ <p>
+ <span class="emphasis"><i class="EMPHASIS"><tt class=
+ "LITERAL">/.*/adv((er)?ts?|ertis(ing|ements?))?/</tt></i></span> -
+ We have several literal forward slashes again (<span class=
+ "QUOTE">"/"</span>), so we are building another expression that is
+ a file path statement. We have another <span class=
+ "QUOTE">".*"</span>, so we are matching against any conceivable
+ sub-path, just so it matches our expression. The only true literal
+ that <span class="emphasis"><i class="EMPHASIS">must
+ match</i></span> our pattern is <span class=
+ "APPLICATION">adv</span>, together with the forward slashes. What
+ comes after the <span class="QUOTE">"adv"</span> string is the
+ interesting part.
+ </p>
+ <p>
+ Remember the <span class="QUOTE">"?"</span> means the preceding
+ expression (either a literal character or anything grouped with
+ <span class="QUOTE">"(...)"</span> in this case) can exist or not,
+ since this means either zero or one match. So <span class=
+ "QUOTE">"((er)?ts?|ertis(ing|ements?))"</span> is optional, as are
+ the individual sub-expressions: <span class="QUOTE">"(er)"</span>,
+ <span class="QUOTE">"(ing|ements?)"</span>, and the <span class=
+ "QUOTE">"s"</span>. The <span class="QUOTE">"|"</span> means <span
+ class="QUOTE">"or"</span>. We have two of those. For instance,
+ <span class="QUOTE">"(ing|ements?)"</span>, can expand to match
+ either <span class="QUOTE">"ing"</span> <span class="emphasis"><i
+ class="EMPHASIS">OR</i></span> <span class=
+ "QUOTE">"ements?"</span>. What is being done here, is an attempt at
+ matching as many variations of <span class=
+ "QUOTE">"advertisement"</span>, and similar, as possible. So this
+ would expand to match just <span class="QUOTE">"adv"</span>, or
+ <span class="QUOTE">"advert"</span>, or <span class=
+ "QUOTE">"adverts"</span>, or <span class=
+ "QUOTE">"advertising"</span>, or <span class=
+ "QUOTE">"advertisement"</span>, or <span class=
+ "QUOTE">"advertisements"</span>. You get the idea. But it would not
+ match <span class="QUOTE">"advertizements"</span> (with a <span
+ class="QUOTE">"z"</span>). We could fix that by changing our
+ regular expression to: <span class=
+ "QUOTE">"/.*/adv((er)?ts?|erti(s|z)(ing|ements?))?/"</span>, which
+ would then match either spelling.
+ </p>
+ <p>
+ <span class="emphasis"><i class="EMPHASIS"><tt class=
+ "LITERAL">/.*/advert[0-9]+\.(gif|jpe?g)</tt></i></span> - Again
+ another path statement with forward slashes. Anything in the square
+ brackets <span class="QUOTE">"[ ]"</span> can be matched. This is
+ using <span class="QUOTE">"0-9"</span> as a shorthand expression to
+ mean any digit one through nine. It is the same as saying <span
+ class="QUOTE">"0123456789"</span>. So any digit matches. The <span
+ class="QUOTE">"+"</span> means one or more of the preceding
+ expression must be included. The preceding expression here is what
+ is in the square brackets -- in this case, any digit one through
+ nine. Then, at the end, we have a grouping: <span class=
+ "QUOTE">"(gif|jpe?g)"</span>. This includes a <span class=
+ "QUOTE">"|"</span>, so this needs to match the expression on either
+ side of that bar character also. A simple <span class=
+ "QUOTE">"gif"</span> on one side, and the other side will in turn
+ match either <span class="QUOTE">"jpeg"</span> or <span class=
+ "QUOTE">"jpg"</span>, since the <span class="QUOTE">"?"</span>
+ means the letter <span class="QUOTE">"e"</span> is optional and can
+ be matched once or not at all. So we are building an expression
+ here to match image GIF or JPEG type image file. It must include
+ the literal string <span class="QUOTE">"advert"</span>, then one or
+ more digits, and a <span class="QUOTE">"."</span> (which is now a
+ literal, and not a special character, since it is escaped with
+ <span class="QUOTE">"\"</span>), and lastly either <span class=
+ "QUOTE">"gif"</span>, or <span class="QUOTE">"jpeg"</span>, or
+ <span class="QUOTE">"jpg"</span>. Some possible matches would
+ include: <span class="QUOTE">"//advert1.jpg"</span>, <span class=
+ "QUOTE">"/nasty/ads/advert1234.gif"</span>, <span class=
+ "QUOTE">"/banners/from/hell/advert99.jpg"</span>. It would not
+ match <span class="QUOTE">"advert1.gif"</span> (no leading slash),
+ or <span class="QUOTE">"/adverts232.jpg"</span> (the expression
+ does not include an <span class="QUOTE">"s"</span>), or <span
+ class="QUOTE">"/advert1.jsp"</span> (<span class=
+ "QUOTE">"jsp"</span> is not in the expression anywhere).
+ </p>
+ <p>
+ We are barely scratching the surface of regular expressions here so
+ that you can understand the default <span class=
+ "APPLICATION">Privoxy</span> configuration files, and maybe use
+ this knowledge to customize your own installation. There is much,
+ much more that can be done with regular expressions. Now that you
+ know enough to get started, you can learn more on your own :/
+ </p>
+ <p>
+ More reading on Perl Compatible Regular expressions: <a href=
+ "http://perldoc.perl.org/perlre.html" target=
+ "_top">http://perldoc.perl.org/perlre.html</a>
+ </p>
+ <p>
+ For information on regular expression based substitutions and their
+ applications in filters, please see the <a href=
+ "filter-file.html">filter file tutorial</a> in this manual.
+ </p>
+ </div>
+ <div class="SECT2">
+ <h2 class="SECT2">
+ <a name="INTERNAL-PAGES">14.2. Privoxy's Internal Pages</a>
+ </h2>
+ <p>
+ Since <span class="APPLICATION">Privoxy</span> proxies each
+ requested web page, it is easy for <span class=
+ "APPLICATION">Privoxy</span> to trap certain special URLs. In this
+ way, we can talk directly to <span class=
+ "APPLICATION">Privoxy</span>, and see how it is configured, see how
+ our rules are being applied, change these rules and other
+ configuration options, and even turn <span class=
+ "APPLICATION">Privoxy's</span> filtering off, all with a web
+ browser.
+ </p>
+ <p>
+ The URLs listed below are the special ones that allow direct access
+ to <span class="APPLICATION">Privoxy</span>. Of course, <span
+ class="APPLICATION">Privoxy</span> must be running to access these.
+ If not, you will get a friendly error message. Internet access is
+ not necessary either.
+ </p>
+ <p>
+ </p>
+ <ul>
+ <li>
+ <p>
+ Privoxy main page:
+ </p>
+ <a name="AEN5923"></a>
+ <blockquote class="BLOCKQUOTE">
+ <p>
+ <a href="http://config.privoxy.org/" target=
+ "_top">http://config.privoxy.org/</a>
+ </p>
+ </blockquote>
+ <p>
+ There is a shortcut: <a href="http://p.p/" target=
+ "_top">http://p.p/</a> (But it doesn't provide a fall-back to a
+ real page, in case the request is not sent through <span class=
+ "APPLICATION">Privoxy</span>)
+ </p>
+ </li>
+ <li>
+ <p>
+ Show information about the current configuration, including
+ viewing and editing of actions files:
+ </p>
+ <a name="AEN5931"></a>
+ <blockquote class="BLOCKQUOTE">
+ <p>
+ <a href="http://config.privoxy.org/show-status" target=
+ "_top">http://config.privoxy.org/show-status</a>
+ </p>
+ </blockquote>
+ </li>
+ <li>
+ <p>
+ Show the source code version numbers:
+ </p>
+ <a name="AEN5936"></a>
+ <blockquote class="BLOCKQUOTE">
+ <p>
+ <a href="http://config.privoxy.org/show-version" target=
+ "_top">http://config.privoxy.org/show-version</a>
+ </p>
+ </blockquote>
+ </li>
+ <li>
+ <p>
+ Show the browser's request headers:
+ </p>
+ <a name="AEN5941"></a>
+ <blockquote class="BLOCKQUOTE">
+ <p>
+ <a href="http://config.privoxy.org/show-request" target=
+ "_top">http://config.privoxy.org/show-request</a>
+ </p>
+ </blockquote>
+ </li>
+ <li>
+ <p>
+ Show which actions apply to a URL and why:
+ </p>
+ <a name="AEN5946"></a>
+ <blockquote class="BLOCKQUOTE">
+ <p>
+ <a href="http://config.privoxy.org/show-url-info" target=
+ "_top">http://config.privoxy.org/show-url-info</a>
+ </p>
+ </blockquote>
+ </li>
+ <li>
+ <p>
+ Toggle Privoxy on or off. This feature can be turned off/on in
+ the main <tt class="FILENAME">config</tt> file. When toggled
+ <span class="QUOTE">"off"</span>, <span class=
+ "QUOTE">"Privoxy"</span> continues to run, but only as a
+ pass-through proxy, with no actions taking place:
+ </p>
+ <a name="AEN5954"></a>
+ <blockquote class="BLOCKQUOTE">
+ <p>
+ <a href="http://config.privoxy.org/toggle" target=
+ "_top">http://config.privoxy.org/toggle</a>
+ </p>
+ </blockquote>
+ <p>
+ Short cuts. Turn off, then on:
+ </p>
+ <a name="AEN5958"></a>
+ <blockquote class="BLOCKQUOTE">
+ <p>
+ <a href="http://config.privoxy.org/toggle?set=disable"
+ target=
+ "_top">http://config.privoxy.org/toggle?set=disable</a>
+ </p>
+ </blockquote>
+ <a name="AEN5961"></a>
+ <blockquote class="BLOCKQUOTE">
+ <p>
+ <a href="http://config.privoxy.org/toggle?set=enable" target=
+ "_top">http://config.privoxy.org/toggle?set=enable</a>
+ </p>
+ </blockquote>
+ </li>
+ </ul>
+ </div>
+ <div class="SECT2">
+ <h2 class="SECT2">
+ <a name="CHAIN">14.3. Chain of Events</a>
+ </h2>
+ <p>
+ Let's take a quick look at how some of <span class=
+ "APPLICATION">Privoxy's</span> core features are triggered, and the
+ ensuing sequence of events when a web page is requested by your
+ browser:
+ </p>
+ <p>
+ </p>
+ <ul>
+ <li>
+ <p>
+ First, your web browser requests a web page. The browser knows
+ to send the request to <span class=
+ "APPLICATION">Privoxy</span>, which will in turn, relay the
+ request to the remote web server after passing the following
+ tests:
+ </p>
+ </li>
+ <li>
+ <p>
+ <span class="APPLICATION">Privoxy</span> traps any request for
+ its own internal CGI pages (e.g <a href="http://p.p/" target=
+ "_top">http://p.p/</a>) and sends the CGI page back to the
+ browser.
+ </p>
+ </li>
+ <li>
+ <p>
+ Next, <span class="APPLICATION">Privoxy</span> checks to see if
+ the URL matches any <a href="actions-file.html#BLOCK"><span
+ class="QUOTE">"+block"</span></a> patterns. If so, the URL is
+ then blocked, and the remote web server will not be contacted.
+ <a href="actions-file.html#HANDLE-AS-IMAGE"><span class=
+ "QUOTE">"+handle-as-image"</span></a> and <a href=
+ "actions-file.html#HANDLE-AS-EMPTY-DOCUMENT"><span class=
+ "QUOTE">"+handle-as-empty-document"</span></a> are then
+ checked, and if there is no match, an HTML <span class=
+ "QUOTE">"BLOCKED"</span> page is sent back to the browser.
+ Otherwise, if it does match, an image is returned for the
+ former, and an empty text document for the latter. The type of
+ image would depend on the setting of <a href=
+ "actions-file.html#SET-IMAGE-BLOCKER"><span class=
+ "QUOTE">"+set-image-blocker"</span></a> (blank, checkerboard
+ pattern, or an HTTP redirect to an image elsewhere).
+ </p>
+ </li>
+ <li>
+ <p>
+ Untrusted URLs are blocked. If URLs are being added to the <tt
+ class="FILENAME">trust</tt> file, then that is done.
+ </p>
+ </li>
+ <li>
+ <p>
+ If the URL pattern matches the <a href=
+ "actions-file.html#FAST-REDIRECTS"><span class=
+ "QUOTE">"+fast-redirects"</span></a> action, it is then
+ processed. Unwanted parts of the requested URL are stripped.
+ </p>
+ </li>
+ <li>
+ <p>
+ Now the rest of the client browser's request headers are
+ processed. If any of these match any of the relevant actions
+ (e.g. <a href="actions-file.html#HIDE-USER-AGENT"><span class=
+ "QUOTE">"+hide-user-agent"</span></a>, etc.), headers are
+ suppressed or forged as determined by these actions and their
+ parameters.
+ </p>
+ </li>
+ <li>
+ <p>
+ Now the web server starts sending its response back (i.e.
+ typically a web page).
+ </p>
+ </li>
+ <li>
+ <p>
+ First, the server headers are read and processed to determine,
+ among other things, the MIME type (document type) and encoding.
+ The headers are then filtered as determined by the <a href=
+ "actions-file.html#CRUNCH-INCOMING-COOKIES"><span class=
+ "QUOTE">"+crunch-incoming-cookies"</span></a>, <a href=
+ "actions-file.html#SESSION-COOKIES-ONLY"><span class=
+ "QUOTE">"+session-cookies-only"</span></a>, and <a href=
+ "actions-file.html#DOWNGRADE-HTTP-VERSION"><span class=
+ "QUOTE">"+downgrade-http-version"</span></a> actions.
+ </p>
+ </li>
+ <li>
+ <p>
+ If any <a href="actions-file.html#FILTER"><span class=
+ "QUOTE">"+filter"</span></a> action or <a href=
+ "actions-file.html#DEANIMATE-GIFS"><span class=
+ "QUOTE">"+deanimate-gifs"</span></a> action applies (and the
+ document type fits the action), the rest of the page is read
+ into memory (up to a configurable limit). Then the filter rules
+ (from <tt class="FILENAME">default.filter</tt> and any other
+ filter files) are processed against the buffered content.
+ Filters are applied in the order they are specified in one of
+ the filter files. Animated GIFs, if present, are reduced to
+ either the first or last frame, depending on the action
+ setting.The entire page, which is now filtered, is then sent by
+ <span class="APPLICATION">Privoxy</span> back to your browser.
+ </p>
+ <p>
+ If neither a <a href="actions-file.html#FILTER"><span class=
+ "QUOTE">"+filter"</span></a> action or <a href=
+ "actions-file.html#DEANIMATE-GIFS"><span class=
+ "QUOTE">"+deanimate-gifs"</span></a> matches, then <span class=
+ "APPLICATION">Privoxy</span> passes the raw data through to the
+ client browser as it becomes available.
+ </p>
+ </li>
+ <li>
+ <p>
+ As the browser receives the now (possibly filtered) page
+ content, it reads and then requests any URLs that may be
+ embedded within the page source, e.g. ad images, stylesheets,
+ JavaScript, other HTML documents (e.g. frames), sounds, etc.
+ For each of these objects, the browser issues a separate
+ request (this is easily viewable in <span class=
+ "APPLICATION">Privoxy's</span> logs). And each such request is
+ in turn processed just as above. Note that a complex web page
+ will have many, many such embedded URLs. If these secondary
+ requests are to a different server, then quite possibly a very
+ differing set of actions is triggered.
+ </p>
+ </li>
+ </ul>
+
+ <p>
+ NOTE: This is somewhat of a simplistic overview of what happens
+ with each URL request. For the sake of brevity and simplicity, we
+ have focused on <span class="APPLICATION">Privoxy's</span> core
+ features only.
+ </p>
+ </div>
+ <div class="SECT2">
+ <h2 class="SECT2">
+ <a name="ACTIONSANAT">14.4. Troubleshooting: Anatomy of an
+ Action</a>
+ </h2>
+ <p>
+ The way <span class="APPLICATION">Privoxy</span> applies <a href=
+ "actions-file.html#ACTIONS">actions</a> and <a href=
+ "actions-file.html#FILTER">filters</a> to any given URL can be
+ complex, and not always so easy to understand what is happening.
+ And sometimes we need to be able to <span class="emphasis"><i
+ class="EMPHASIS">see</i></span> just what <span class=
+ "APPLICATION">Privoxy</span> is doing. Especially, if something
+ <span class="APPLICATION">Privoxy</span> is doing is causing us a
+ problem inadvertently. It can be a little daunting to look at the
+ actions and filters files themselves, since they tend to be filled
+ with <a href="appendix.html#REGEX">regular expressions</a> whose
+ consequences are not always so obvious.
+ </p>
+ <p>
+ One quick test to see if <span class="APPLICATION">Privoxy</span>
+ is causing a problem or not, is to disable it temporarily. This
+ should be the first troubleshooting step (be sure to flush caches
+ afterward!). Looking at the logs is a good idea too. (Note that
+ both the toggle feature and logging are enabled via <tt class=
+ "FILENAME">config</tt> file settings, and may need to be turned
+ <span class="QUOTE">"on"</span>.)
+ </p>
+ <p>
+ Another easy troubleshooting step to try is if you have done any
+ customization of your installation, revert back to the installed
+ defaults and see if that helps. There are times the developers get
+ complaints about one thing or another, and the problem is more
+ related to a customized configuration issue.
+ </p>
+ <p>
+ <span class="APPLICATION">Privoxy</span> also provides the <a href=
+ "http://config.privoxy.org/show-url-info" target=
+ "_top">http://config.privoxy.org/show-url-info</a> page that can
+ show us very specifically how <span class=
+ "APPLICATION">actions</span> are being applied to any given URL.
+ This is a big help for troubleshooting.
+ </p>
+ <p>
+ First, enter one URL (or partial URL) at the prompt, and then <span
+ class="APPLICATION">Privoxy</span> will tell us how the current
+ configuration will handle it. This will not help with filtering
+ effects (i.e. the <a href="actions-file.html#FILTER"><span class=
+ "QUOTE">"+filter"</span></a> action) from one of the filter files
+ since this is handled very differently and not so easy to trap! It
+ also will not tell you about any other URLs that may be embedded
+ within the URL you are testing. For instance, images such as ads
+ are expressed as URLs within the raw page source of HTML pages. So
+ you will only get info for the actual URL that is pasted into the
+ prompt area -- not any sub-URLs. If you want to know about embedded
+ URLs like ads, you will have to dig those out of the HTML source.
+ Use your browser's <span class="QUOTE">"View Page Source"</span>
+ option for this. Or right click on the ad, and grab the URL.
+ </p>
+ <p>
+ Let's try an example, <a href="http://google.com" target=
+ "_top">google.com</a>, and look at it one section at a time in a
+ sample configuration (your real configuration may vary):
+ </p>
+ <p>
+ </p>
+ <table border="0" bgcolor="#E0E0E0" width="100%">
+ <tr>
+ <td>
+<pre class="SCREEN">
Matches for http://www.google.com:
In file: default.action <span class="GUIBUTTON">[ View ]</span> <span class=
"GUIBUTTON">[ Edit ]</span>
(no matches in this file)
</pre>
- </td>
- </tr>
- </table>
-
- <p>This is telling us how we have defined our <a href=
- "actions-file.html#ACTIONS"><span class="QUOTE">"actions"</span></a>,
- and which ones match for our test case, <span class=
- "QUOTE">"google.com"</span>. Displayed is all the actions that are
- available to us. Remember, the <tt class="LITERAL">+</tt> sign denotes
- <span class="QUOTE">"on"</span>. <tt class="LITERAL">-</tt> denotes
- <span class="QUOTE">"off"</span>. So some are <span class=
- "QUOTE">"on"</span> here, but many are <span class=
- "QUOTE">"off"</span>. Each example we try may provide a slightly
- different end result, depending on our configuration directives.</p>
-
- <p>The first listing is for our <tt class=
- "FILENAME">default.action</tt> file. The large, multi-line listing, is
- how the actions are set to match for all URLs, i.e. our default
- settings. If you look at your <span class="QUOTE">"actions"</span>
- file, this would be the section just below the <span class=
- "QUOTE">"aliases"</span> section near the top. This will apply to all
- URLs as signified by the single forward slash at the end of the listing
- -- <span class="QUOTE">" / "</span>.</p>
-
- <p>But we have defined additional actions that would be exceptions to
- these general rules, and then we list specific URLs (or patterns) that
- these exceptions would apply to. Last match wins. Just below this then
- are two explicit matches for <span class="QUOTE">".google.com"</span>.
- The first is negating our previous cookie setting, which was for
- <a href="actions-file.html#SESSION-COOKIES-ONLY"><span class=
- "QUOTE">"+session-cookies-only"</span></a> (i.e. not persistent). So we
- will allow persistent cookies for google, at least that is how it is in
- this example. The second turns <span class="emphasis"><i class=
- "EMPHASIS">off</i></span> any <a href=
- "actions-file.html#FAST-REDIRECTS"><span class=
- "QUOTE">"+fast-redirects"</span></a> action, allowing this to take
- place unmolested. Note that there is a leading dot here -- <span class=
- "QUOTE">".google.com"</span>. This will match any hosts and
- sub-domains, in the google.com domain also, such as <span class=
- "QUOTE">"www.google.com"</span> or <span class=
- "QUOTE">"mail.google.com"</span>. But it would not match <span class=
- "QUOTE">"www.google.de"</span>! So, apparently, we have these two
- actions defined as exceptions to the general rules at the top somewhere
- in the lower part of our <tt class="FILENAME">default.action</tt> file,
- and <span class="QUOTE">"google.com"</span> is referenced somewhere in
- these latter sections.</p>
-
- <p>Then, for our <tt class="FILENAME">user.action</tt> file, we again
- have no hits. So there is nothing google-specific that we might have
- added to our own, local configuration. If there was, those actions
- would over-rule any actions from previously processed files, such as
- <tt class="FILENAME">default.action</tt>. <tt class=
- "FILENAME">user.action</tt> typically has the last word. This is the
- best place to put hard and fast exceptions,</p>
-
- <p>And finally we pull it all together in the bottom section and
- summarize how <span class="APPLICATION">Privoxy</span> is applying all
- its <span class="QUOTE">"actions"</span> to <span class=
- "QUOTE">"google.com"</span>:</p>
-
- <table border="0" bgcolor="#E0E0E0" width="100%">
- <tr>
- <td>
- <pre class="SCREEN">
+ </td>
+ </tr>
+ </table>
+
+ <p>
+ This is telling us how we have defined our <a href=
+ "actions-file.html#ACTIONS"><span class=
+ "QUOTE">"actions"</span></a>, and which ones match for our test
+ case, <span class="QUOTE">"google.com"</span>. Displayed is all the
+ actions that are available to us. Remember, the <tt class=
+ "LITERAL">+</tt> sign denotes <span class="QUOTE">"on"</span>. <tt
+ class="LITERAL">-</tt> denotes <span class="QUOTE">"off"</span>. So
+ some are <span class="QUOTE">"on"</span> here, but many are <span
+ class="QUOTE">"off"</span>. Each example we try may provide a
+ slightly different end result, depending on our configuration
+ directives.
+ </p>
+ <p>
+ The first listing is for our <tt class=
+ "FILENAME">default.action</tt> file. The large, multi-line listing,
+ is how the actions are set to match for all URLs, i.e. our default
+ settings. If you look at your <span class="QUOTE">"actions"</span>
+ file, this would be the section just below the <span class=
+ "QUOTE">"aliases"</span> section near the top. This will apply to
+ all URLs as signified by the single forward slash at the end of the
+ listing -- <span class="QUOTE">" / "</span>.
+ </p>
+ <p>
+ But we have defined additional actions that would be exceptions to
+ these general rules, and then we list specific URLs (or patterns)
+ that these exceptions would apply to. Last match wins. Just below
+ this then are two explicit matches for <span class=
+ "QUOTE">".google.com"</span>. The first is negating our previous
+ cookie setting, which was for <a href=
+ "actions-file.html#SESSION-COOKIES-ONLY"><span class=
+ "QUOTE">"+session-cookies-only"</span></a> (i.e. not persistent).
+ So we will allow persistent cookies for google, at least that is
+ how it is in this example. The second turns <span class=
+ "emphasis"><i class="EMPHASIS">off</i></span> any <a href=
+ "actions-file.html#FAST-REDIRECTS"><span class=
+ "QUOTE">"+fast-redirects"</span></a> action, allowing this to take
+ place unmolested. Note that there is a leading dot here -- <span
+ class="QUOTE">".google.com"</span>. This will match any hosts and
+ sub-domains, in the google.com domain also, such as <span class=
+ "QUOTE">"www.google.com"</span> or <span class=
+ "QUOTE">"mail.google.com"</span>. But it would not match <span
+ class="QUOTE">"www.google.de"</span>! So, apparently, we have these
+ two actions defined as exceptions to the general rules at the top
+ somewhere in the lower part of our <tt class=
+ "FILENAME">default.action</tt> file, and <span class=
+ "QUOTE">"google.com"</span> is referenced somewhere in these latter
+ sections.
+ </p>
+ <p>
+ Then, for our <tt class="FILENAME">user.action</tt> file, we again
+ have no hits. So there is nothing google-specific that we might
+ have added to our own, local configuration. If there was, those
+ actions would over-rule any actions from previously processed
+ files, such as <tt class="FILENAME">default.action</tt>. <tt class=
+ "FILENAME">user.action</tt> typically has the last word. This is
+ the best place to put hard and fast exceptions,
+ </p>
+ <p>
+ And finally we pull it all together in the bottom section and
+ summarize how <span class="APPLICATION">Privoxy</span> is applying
+ all its <span class="QUOTE">"actions"</span> to <span class=
+ "QUOTE">"google.com"</span>:
+ </p>
+ <p>
+ </p>
+ <table border="0" bgcolor="#E0E0E0" width="100%">
+ <tr>
+ <td>
+<pre class="SCREEN">
Final results:
-add-header
-session-cookies-only
+set-image-blocker {pattern}
</pre>
- </td>
- </tr>
- </table>
-
- <p>Notice the only difference here to the previous listing, is to
- <span class="QUOTE">"fast-redirects"</span> and <span class=
- "QUOTE">"session-cookies-only"</span>, which are activated specifically
- for this site in our configuration, and thus show in the <span class=
- "QUOTE">"Final Results"</span>.</p>
-
- <p>Now another example, <span class=
- "QUOTE">"ad.doubleclick.net"</span>:</p>
-
- <table border="0" bgcolor="#E0E0E0" width="100%">
- <tr>
- <td>
- <pre class="SCREEN">
+ </td>
+ </tr>
+ </table>
+
+ <p>
+ Notice the only difference here to the previous listing, is to
+ <span class="QUOTE">"fast-redirects"</span> and <span class=
+ "QUOTE">"session-cookies-only"</span>, which are activated
+ specifically for this site in our configuration, and thus show in
+ the <span class="QUOTE">"Final Results"</span>.
+ </p>
+ <p>
+ Now another example, <span class=
+ "QUOTE">"ad.doubleclick.net"</span>:
+ </p>
+ <p>
+ </p>
+ <table border="0" bgcolor="#E0E0E0" width="100%">
+ <tr>
+ <td>
+<pre class="SCREEN">
{ +block{Domains starts with "ad"} }
ad*.
{ +block{Doubleclick banner server} +handle-as-image }
.[a-vx-z]*.doubleclick.net
</pre>
- </td>
- </tr>
- </table>
-
- <p>We'll just show the interesting part here - the explicit matches. It
- is matched three different times. Two <span class=
- "QUOTE">"+block{}"</span> sections, and a <span class="QUOTE">"+block{}
- +handle-as-image"</span>, which is the expanded form of one of our
- aliases that had been defined as: <span class=
- "QUOTE">"+block-as-image"</span>. (<a href=
- "actions-file.html#ALIASES"><span class="QUOTE">"Aliases"</span></a>
- are defined in the first section of the actions file and typically used
- to combine more than one action.)</p>
-
- <p>Any one of these would have done the trick and blocked this as an
- unwanted image. This is unnecessarily redundant since the last case
- effectively would also cover the first. No point in taking chances with
- these guys though ;-) Note that if you want an ad or obnoxious URL to
- be invisible, it should be defined as <span class=
- "QUOTE">"ad.doubleclick.net"</span> is done here -- as both a <a href=
- "actions-file.html#BLOCK"><span class="QUOTE">"+block{}"</span></a>
- <span class="emphasis"><i class="EMPHASIS">and</i></span> an <a href=
- "actions-file.html#HANDLE-AS-IMAGE"><span class=
- "QUOTE">"+handle-as-image"</span></a>. The custom alias <span class=
- "QUOTE">"<tt class="LITERAL">+block-as-image</tt>"</span> just
- simplifies the process and make it more readable.</p>
-
- <p>One last example. Let's try <span class=
- "QUOTE">"http://www.example.net/adsl/HOWTO/"</span>. This one is giving
- us problems. We are getting a blank page. Hmmm ...</p>
-
- <table border="0" bgcolor="#E0E0E0" width="100%">
- <tr>
- <td>
- <pre class="SCREEN">
+ </td>
+ </tr>
+ </table>
+
+ <p>
+ We'll just show the interesting part here - the explicit matches.
+ It is matched three different times. Two <span class=
+ "QUOTE">"+block{}"</span> sections, and a <span class=
+ "QUOTE">"+block{} +handle-as-image"</span>, which is the expanded
+ form of one of our aliases that had been defined as: <span class=
+ "QUOTE">"+block-as-image"</span>. (<a href=
+ "actions-file.html#ALIASES"><span class=
+ "QUOTE">"Aliases"</span></a> are defined in the first section of
+ the actions file and typically used to combine more than one
+ action.)
+ </p>
+ <p>
+ Any one of these would have done the trick and blocked this as an
+ unwanted image. This is unnecessarily redundant since the last case
+ effectively would also cover the first. No point in taking chances
+ with these guys though ;-) Note that if you want an ad or obnoxious
+ URL to be invisible, it should be defined as <span class=
+ "QUOTE">"ad.doubleclick.net"</span> is done here -- as both a <a
+ href="actions-file.html#BLOCK"><span class=
+ "QUOTE">"+block{}"</span></a> <span class="emphasis"><i class=
+ "EMPHASIS">and</i></span> an <a href=
+ "actions-file.html#HANDLE-AS-IMAGE"><span class=
+ "QUOTE">"+handle-as-image"</span></a>. The custom alias <span
+ class="QUOTE">"<tt class="LITERAL">+block-as-image</tt>"</span>
+ just simplifies the process and make it more readable.
+ </p>
+ <p>
+ One last example. Let's try <span class=
+ "QUOTE">"http://www.example.net/adsl/HOWTO/"</span>. This one is
+ giving us problems. We are getting a blank page. Hmmm ...
+ </p>
+ <p>
+ </p>
+ <table border="0" bgcolor="#E0E0E0" width="100%">
+ <tr>
+ <td>
+<pre class="SCREEN">
Matches for http://www.example.net/adsl/HOWTO/:
In file: default.action <span class="GUIBUTTON">[ View ]</span> <span class=
{ +block{Path contains "ads".} +handle-as-image }
/ads
</pre>
- </td>
- </tr>
- </table>
-
- <p>Ooops, the <span class="QUOTE">"/adsl/"</span> is matching
- <span class="QUOTE">"/ads"</span> in our configuration! But we did not
- want this at all! Now we see why we get the blank page. It is actually
- triggering two different actions here, and the effects are aggregated
- so that the URL is blocked, and <span class=
- "APPLICATION">Privoxy</span> is told to treat the block as if it were
- an image. But this is, of course, all wrong. We could now add a new
- action below this (or better in our own <tt class=
- "FILENAME">user.action</tt> file) that explicitly <span class=
- "emphasis"><i class="EMPHASIS">un</i></span> blocks ( <a href=
- "actions-file.html#BLOCK"><span class="QUOTE">"{-block}"</span></a>)
- paths with <span class="QUOTE">"adsl"</span> in them (remember, last
- match in the configuration wins). There are various ways to handle such
- exceptions. Example:</p>
-
- <table border="0" bgcolor="#E0E0E0" width="100%">
- <tr>
- <td>
- <pre class="SCREEN">
+ </td>
+ </tr>
+ </table>
+
+ <p>
+ Ooops, the <span class="QUOTE">"/adsl/"</span> is matching <span
+ class="QUOTE">"/ads"</span> in our configuration! But we did not
+ want this at all! Now we see why we get the blank page. It is
+ actually triggering two different actions here, and the effects are
+ aggregated so that the URL is blocked, and <span class=
+ "APPLICATION">Privoxy</span> is told to treat the block as if it
+ were an image. But this is, of course, all wrong. We could now add
+ a new action below this (or better in our own <tt class=
+ "FILENAME">user.action</tt> file) that explicitly <span class=
+ "emphasis"><i class="EMPHASIS">un</i></span> blocks ( <a href=
+ "actions-file.html#BLOCK"><span class=
+ "QUOTE">"{-block}"</span></a>) paths with <span class=
+ "QUOTE">"adsl"</span> in them (remember, last match in the
+ configuration wins). There are various ways to handle such
+ exceptions. Example:
+ </p>
+ <p>
+ </p>
+ <table border="0" bgcolor="#E0E0E0" width="100%">
+ <tr>
+ <td>
+<pre class="SCREEN">
{ -block }
/adsl
</pre>
- </td>
- </tr>
- </table>
-
- <p>Now the page displays ;-) Remember to flush your browser's caches
- when making these kinds of changes to your configuration to insure that
- you get a freshly delivered page! Or, try using <tt class=
- "LITERAL">Shift+Reload</tt>.</p>
-
- <p>But now what about a situation where we get no explicit matches like
- we did with:</p>
-
- <table border="0" bgcolor="#E0E0E0" width="100%">
- <tr>
- <td>
- <pre class="SCREEN">
+ </td>
+ </tr>
+ </table>
+
+ <p>
+ Now the page displays ;-) Remember to flush your browser's caches
+ when making these kinds of changes to your configuration to insure
+ that you get a freshly delivered page! Or, try using <tt class=
+ "LITERAL">Shift+Reload</tt>.
+ </p>
+ <p>
+ But now what about a situation where we get no explicit matches
+ like we did with:
+ </p>
+ <p>
+ </p>
+ <table border="0" bgcolor="#E0E0E0" width="100%">
+ <tr>
+ <td>
+<pre class="SCREEN">
{ +block{Path starts with "ads".} +handle-as-image }
/ads
</pre>
- </td>
- </tr>
- </table>
-
- <p>That actually was very helpful and pointed us quickly to where the
- problem was. If you don't get this kind of match, then it means one of
- the default rules in the first section of <tt class=
- "FILENAME">default.action</tt> is causing the problem. This would
- require some guesswork, and maybe a little trial and error to isolate
- the offending rule. One likely cause would be one of the <a href=
- "actions-file.html#FILTER"><span class="QUOTE">"+filter"</span></a>
- actions. These tend to be harder to troubleshoot. Try adding the URL
- for the site to one of aliases that turn off <a href=
- "actions-file.html#FILTER"><span class=
- "QUOTE">"+filter"</span></a>:</p>
-
- <table border="0" bgcolor="#E0E0E0" width="100%">
- <tr>
- <td>
- <pre class="SCREEN">
+ </td>
+ </tr>
+ </table>
+
+ <p>
+ That actually was very helpful and pointed us quickly to where the
+ problem was. If you don't get this kind of match, then it means one
+ of the default rules in the first section of <tt class=
+ "FILENAME">default.action</tt> is causing the problem. This would
+ require some guesswork, and maybe a little trial and error to
+ isolate the offending rule. One likely cause would be one of the <a
+ href="actions-file.html#FILTER"><span class=
+ "QUOTE">"+filter"</span></a> actions. These tend to be harder to
+ troubleshoot. Try adding the URL for the site to one of aliases
+ that turn off <a href="actions-file.html#FILTER"><span class=
+ "QUOTE">"+filter"</span></a>:
+ </p>
+ <p>
+ </p>
+ <table border="0" bgcolor="#E0E0E0" width="100%">
+ <tr>
+ <td>
+<pre class="SCREEN">
{ shop }
.quietpc.com
.worldpay.com # for quietpc.com
.scan.co.uk
.forbes.com
</pre>
- </td>
- </tr>
- </table>
-
- <p><span class="QUOTE">"<tt class="LITERAL">{ shop }</tt>"</span> is an
- <span class="QUOTE">"alias"</span> that expands to <span class=
- "QUOTE">"<tt class="LITERAL">{ -filter -session-cookies-only
- }</tt>"</span>. Or you could do your own exception to negate
- filtering:</p>
-
- <table border="0" bgcolor="#E0E0E0" width="100%">
- <tr>
- <td>
- <pre class="SCREEN">
+ </td>
+ </tr>
+ </table>
+
+ <p>
+ <span class="QUOTE">"<tt class="LITERAL">{ shop }</tt>"</span> is
+ an <span class="QUOTE">"alias"</span> that expands to <span class=
+ "QUOTE">"<tt class="LITERAL">{ -filter -session-cookies-only
+ }</tt>"</span>. Or you could do your own exception to negate
+ filtering:
+ </p>
+ <p>
+ </p>
+ <table border="0" bgcolor="#E0E0E0" width="100%">
+ <tr>
+ <td>
+<pre class="SCREEN">
{ -filter }
# Disable ALL filter actions for sites in this section
.forbes.com
developer.ibm.com
localhost
</pre>
- </td>
- </tr>
- </table>
-
- <p>This would turn off all filtering for these sites. This is best put
- in <tt class="FILENAME">user.action</tt>, for local site exceptions.
- Note that when a simple domain pattern is used by itself (without the
- subsequent path portion), all sub-pages within that domain are included
- automatically in the scope of the action.</p>
-
- <p>Images that are inexplicably being blocked, may well be hitting the
- <a href="actions-file.html#FILTER-BANNERS-BY-SIZE"><span class=
- "QUOTE">"+filter{banners-by-size}"</span></a> rule, which assumes that
- images of certain sizes are ad banners (works well <span class=
- "emphasis"><i class="EMPHASIS">most of the time</i></span> since these
- tend to be standardized).</p>
-
- <p><span class="QUOTE">"<tt class="LITERAL">{ fragile }</tt>"</span> is
- an alias that disables most actions that are the most likely to cause
- trouble. This can be used as a last resort for problem sites.</p>
-
- <table border="0" bgcolor="#E0E0E0" width="100%">
- <tr>
- <td>
- <pre class="SCREEN">
+ </td>
+ </tr>
+ </table>
+
+ <p>
+ This would turn off all filtering for these sites. This is best put
+ in <tt class="FILENAME">user.action</tt>, for local site
+ exceptions. Note that when a simple domain pattern is used by
+ itself (without the subsequent path portion), all sub-pages within
+ that domain are included automatically in the scope of the action.
+ </p>
+ <p>
+ Images that are inexplicably being blocked, may well be hitting the
+ <a href="actions-file.html#FILTER-BANNERS-BY-SIZE"><span class=
+ "QUOTE">"+filter{banners-by-size}"</span></a> rule, which assumes
+ that images of certain sizes are ad banners (works well <span
+ class="emphasis"><i class="EMPHASIS">most of the time</i></span>
+ since these tend to be standardized).
+ </p>
+ <p>
+ <span class="QUOTE">"<tt class="LITERAL">{ fragile }</tt>"</span>
+ is an alias that disables most actions that are the most likely to
+ cause trouble. This can be used as a last resort for problem sites.
+ </p>
+ <p>
+ </p>
+ <table border="0" bgcolor="#E0E0E0" width="100%">
+ <tr>
+ <td>
+<pre class="SCREEN">
{ fragile }
# Handle with care: easy to break
mail.google.
mybank.example.com
</pre>
+ </td>
+ </tr>
+ </table>
+
+ <p>
+ <span class="emphasis"><i class="EMPHASIS">Remember to flush
+ caches!</i></span> Note that the <tt class=
+ "LITERAL">mail.google</tt> reference lacks the TLD portion (e.g.
+ <span class="QUOTE">".com"</span>). This will effectively match any
+ TLD with <tt class="LITERAL">google</tt> in it, such as <tt class=
+ "LITERAL">mail.google.de.</tt>, just as an example.
+ </p>
+ <p>
+ If this still does not work, you will have to go through the
+ remaining actions one by one to find which one(s) is causing the
+ problem.
+ </p>
+ </div>
+ </div>
+ <div class="NAVFOOTER">
+ <hr align="LEFT" width="100%">
+ <table summary="Footer navigation table" width="100%" border="0"
+ cellpadding="0" cellspacing="0">
+ <tr>
+ <td width="33%" align="left" valign="top">
+ <a href="seealso.html" accesskey="P">Prev</a>
+ </td>
+ <td width="34%" align="center" valign="top">
+ <a href="index.html" accesskey="H">Home</a>
+ </td>
+ <td width="33%" align="right" valign="top">
+
+ </td>
+ </tr>
+ <tr>
+ <td width="33%" align="left" valign="top">
+ See Also
+ </td>
+ <td width="34%" align="center" valign="top">
+
+ </td>
+ <td width="33%" align="right" valign="top">
+
</td>
</tr>
</table>
-
- <p><span class="emphasis"><i class="EMPHASIS">Remember to flush
- caches!</i></span> Note that the <tt class="LITERAL">mail.google</tt>
- reference lacks the TLD portion (e.g. <span class=
- "QUOTE">".com"</span>). This will effectively match any TLD with
- <tt class="LITERAL">google</tt> in it, such as <tt class=
- "LITERAL">mail.google.de.</tt>, just as an example.</p>
-
- <p>If this still does not work, you will have to go through the
- remaining actions one by one to find which one(s) is causing the
- problem.</p>
</div>
- </div>
-
- <div class="NAVFOOTER">
- <hr align="left" width="100%">
-
- <table summary="Footer navigation table" width="100%" border="0"
- cellpadding="0" cellspacing="0">
- <tr>
- <td width="33%" align="left" valign="top"><a href="seealso.html"
- accesskey="P">Prev</a></td>
-
- <td width="34%" align="center" valign="top"><a href="index.html"
- accesskey="H">Home</a></td>
-
- <td width="33%" align="right" valign="top"> </td>
- </tr>
-
- <tr>
- <td width="33%" align="left" valign="top">See Also</td>
-
- <td width="34%" align="center" valign="top"> </td>
-
- <td width="33%" align="right" valign="top"> </td>
- </tr>
- </table>
- </div>
-</body>
+ </body>
</html>
+
projects / privoxy.git / blobdiff