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| author | Joshua Slive <slive@apache.org> | 2002-05-23 14:23:51 +0000 |
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| committer | Joshua Slive <slive@apache.org> | 2002-05-23 14:23:51 +0000 |
| commit | 700dc34d7c5ebc8c847d38671c70ded3f9a56a1e (patch) | |
| tree | e61383e7c4f09556afa12321b88ccaa006f7202e /docs/manual/mod/mod_ext_filter.html.en | |
| parent | dc4ff3c1c7a35ce49f0ba036ea298242976044af (diff) | |
| download | httpd-700dc34d7c5ebc8c847d38671c70ded3f9a56a1e.tar.gz | |
No change here except the filename extensions. Sorry for the massic commit.
git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@95240 13f79535-47bb-0310-9956-ffa450edef68
Diffstat (limited to 'docs/manual/mod/mod_ext_filter.html.en')
| -rw-r--r-- | docs/manual/mod/mod_ext_filter.html.en | 204 |
1 files changed, 204 insertions, 0 deletions
diff --git a/docs/manual/mod/mod_ext_filter.html.en b/docs/manual/mod/mod_ext_filter.html.en new file mode 100644 index 0000000000..1f3f27f49a --- /dev/null +++ b/docs/manual/mod/mod_ext_filter.html.en @@ -0,0 +1,204 @@ +<html xmlns="http://www.w3.org/TR/xhtml1/strict"><head><!-- + XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX + This file is generated from xml source: DO NOT EDIT + XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX + --><title>mod_ext_filter- Apache HTTP Server</title><link href="../style/manual.css" type="text/css" rel="stylesheet"/></head><body><blockquote><div align="center"><img src="../images/sub.gif" alt="[APACHE DOCUMENTATION]"/><h3>Apache HTTP Server Version 2.0</h3></div><h1 align="center">Apache Module mod_ext_filter</h1><table cellspacing="1" cellpadding="0" bgcolor="#cccccc"><tr><td><table bgcolor="#ffffff"><tr><td valign="top"><span class="help">Description:</span></td><td>Pass the response body + through an external program before delivery to the + client</td></tr><tr><td><a href="module-dict.html#Status" class="help">Status:</a></td><td>Experimental</td></tr><tr><td><a href="module-dict.html#ModuleIdentifier" class="help">Module Identifier:</a></td><td>ext_filter_module</td></tr></table></td></tr></table><h2>Summary</h2> + <p>This is an <strong>experimental</strong> module and should + be used with care. Test your <code><a href="mod_ext_filter.html">mod_ext_filter</a></code> + configuration carefully to ensure that it performs the desired + function. You may wish to review <a href="../filter.html"> + this information</a> for background on the Apache filtering + model.</p> + + <p><code><a href="mod_ext_filter.html">mod_ext_filter</a></code> presents a simple and familiar + programming model for filters. With this module, a program + which reads from stdin and writes to stdout (i.e., a Unix-style + filter command) can be a filter for Apache. This filtering + mechanism is much slower than using a filter which is specially + written for the Apache API and runs inside of the Apache server + process, but it does have the following benefits:</p> + + <ul> + <li>the programming model is much simpler</li> + + <li>any programming/scripting language can be used, provided + that it allows the program to read from standard input and + write to standard output</li> + + <li>existing programs can be used unmodified as Apache + filters</li> + </ul> + + <p>Even when the performance characteristics are not suitable + for production use, <code>mod_ext_filter</code> can be used as + a prototype environment for filters.</p> +<h2>Directives</h2><ul><li><a href="#extfilterdefine">ExtFilterDefine</a></li><li><a href="#extfilteroptions">ExtFilterOptions</a></li></ul><h2>Examples</h2> + +<h3>Generating HTML from some other type of response</h3> +<blockquote><table cellpadding="10"><tr><td bgcolor="#eeeeee"><code> +<pre> + # mod_ext_filter directive to define a filter to HTML-ize text/c files + # using the external program /usr/bin/enscript, with the type of the + # result set to text/html + ExtFilterDefine c-to-html mode=output intype=text/c outtype=text/html \ + cmd="/usr/bin/enscript --color -W html -Ec -o - -" + + <Directory "/export/home/trawick/apacheinst/htdocs/c"> + + # core directive to cause the new filter to be run on output + SetOutputFilter c-to-html + + # mod_mime directive to set the type of .c files to text/c + AddType text/c .c + + # mod_ext_filter directive to set the debug level just high + # enough to see a log message per request showing the configuration + # in force + ExtFilterOptions DebugLevel=1 + + </Directory> +</pre> +</code></td></tr></table></blockquote> + + +<h3>Implementing a content encoding filter</h3> +<blockquote><table cellpadding="10"><tr><td bgcolor="#eeeeee"><code> +<pre> + # mod_ext_filter directive to define the external filter + ExtFilterDefine gzip mode=output cmd=/bin/gzip + + <Location /gzipped> + + # core directive to cause the gzip filter to be run on output + SetOutputFilter gzip + + # mod_header directive to add "Content-Encoding: gzip" header field + Header set Content-Encoding gzip + + </Location> +</pre> +</code></td></tr></table></blockquote> + + <p>Note: this gzip example is just for the purposes of illustration. + Please refer to <code><a href="mod_deflate.html">mod_deflate</a></code> for a practical + implementation.</p> + + +<h3>Slowing down the server</h3> +<blockquote><table cellpadding="10"><tr><td bgcolor="#eeeeee"><code> +<pre> + # mod_ext_filter directive to define a filter which runs everything + # through cat; cat doesn't modify anything; it just introduces extra + # pathlength and consumes more resources + ExtFilterDefine slowdown mode=output cmd=/bin/cat preservescontentlength + + <Location /> + + # core directive to cause the slowdown filter to be run several times on + # output + SetOutputFilter slowdown slowdown slowdown + + </Location> +</pre> +</code></td></tr></table></blockquote> + + +<hr/><h2><a name="ExtFilterDefine">ExtFilterDefine</a> <a name="extfilterdefine">Directive</a></h2><table cellpadding="1" cellspacing="0" border="0" bgcolor="#cccccc"><tr><td><table bgcolor="#ffffff"><tr><td><strong>Description: </strong></td><td/></tr><tr><td><a href="directive-dict.html#Syntax" class="help">Syntax:</a></td><td>ExtFilterDefine <em>filtername</em> <em>parameters</em></td></tr><tr><td><a href="directive-dict.html#Context" class="help">Context:</a></td><td>server config</td></tr><tr><td><a href="directive-dict.html#Status" class="help">Status:</a></td><td>Experimental</td></tr><tr><td><a href="directive-dict.html#Module" class="help">Module:</a></td><td>mod_ext_filter</td></tr></table></td></tr></table> + <p>The <code class="directive">ExtFilterDefine</code> directive defines the + characteristics of an external filter, including the program to + run and its arguments.</p> + + <p><em>filtername</em> specifies the name of the filter being + defined. This name can then be used in SetOutputFilter + directives. It must be unique among all registered filters. + <em>At the present time, no error is reported by the + register-filter API, so a problem with duplicate names isn't + reported to the user.</em></p> + + <p>Subsequent parameters can appear in any order and define the + external command to run and certain other characteristics. The + only required parameter is <em>cmd=</em>. These parameters + are:</p> + + <dl> + <dt>cmd=<em>cmdline</em></dt> + + <dd>The <code>cmd=</code> keyword allows you to specify the + external command to run. If there are arguments after the + program name, the command line should be surrounded in + quotation marks.</dd> + + <dt>mode=<em>mode</em></dt> + + <dd><em>mode</em> should be <em>output</em> for now (the + default). In the future, <em>mode=input</em> will be used to + specify a filter for request bodies.</dd> + + <dt>intype=<em>imt</em></dt> + + <dd>This parameter specifies the internet media type (i.e., + MIME type) of documents which should be filtered. By default, + all documents are filtered. If <code>intype=</code> is + specified, the filter will be disabled for documents of other + types.</dd> + + <dt>outtype=<em>imt</em></dt> + + <dd>This parameter specifies the internet media type (i.e., + MIME type) of filtered documents. It is useful when the + filter changes the internet media type as part of the + filtering operation. By default, the internet media type is + unchanged.</dd> + + <dt>PreservesContentLength</dt> + + <dd>The <code>PreservesContentLength</code> keyword specifies + that the filter preserves the content length. This is not the + default, as most filters change the content length. In the + event that the filter doesn't modify the length, this keyword + should be specified.</dd> + </dl> +<hr/><h2><a name="ExtFilterOptions">ExtFilterOptions</a> <a name="extfilteroptions">Directive</a></h2><table cellpadding="1" cellspacing="0" border="0" bgcolor="#cccccc"><tr><td><table bgcolor="#ffffff"><tr><td><strong>Description: </strong></td><td/></tr><tr><td><a href="directive-dict.html#Syntax" class="help">Syntax:</a></td><td>ExtFilterOptions + <em>option</em> [<em>option</em>] ...</td></tr><tr><td><a href="directive-dict.html#Default" class="help">Default:</a></td><td><code>ExtFilterOptions DebugLevel=0 NoLogStderr</code></td></tr><tr><td><a href="directive-dict.html#Context" class="help">Context:</a></td><td>directory</td></tr><tr><td><a href="directive-dict.html#Status" class="help">Status:</a></td><td>Experimental</td></tr><tr><td><a href="directive-dict.html#Module" class="help">Module:</a></td><td>mod_ext_filter</td></tr></table></td></tr></table> + <p>The <code class="directive">ExtFilterOptions</code> directive specifies + special processing options for <code>mod_ext_filter</code>. + <em>Option</em> can be one of</p> + + <dl> + <dt>DebugLevel=<em>n</em></dt> + + <dd> + The <code>DebugLevel</code> keyword allows you to specify + the level of debug messages generated by + <code>mod_ext_filter</code>. By default, no debug messages + are generated. This is equivalent to + <code>DebugLevel=0</code>. With higher numbers, more debug + messages are generated, and server performance will be + degraded. The actual meanings of the numeric values are + described with the definitions of the DBGLVL_ constants + near the beginning of <code>mod_ext_filter.c</code>. + + <p>Note: The core directive LogLevel should be used to + cause debug messages to be stored in the Apache error + log.</p> + </dd> + + <dt>LogStderr | NoLogStderr</dt> + + <dd>The <code>LogStderr</code> keyword specifies that + messages written to standard error by the external filter + program will be saved in the Apache error log. + <code>NoLogStderr</code> disables this feature.</dd> + </dl> + + <p>Example:</p> +<blockquote><table cellpadding="10"><tr><td bgcolor="#eeeeee"><code> + ExtFilterOptions LogStderr DebugLevel=0 +</code></td></tr></table></blockquote> + + <p>Messages written to the filter's standard error will be stored + in the Apache error log. No debug messages will be generated by + <code><a href="mod_ext_filter.html">mod_ext_filter</a></code>. </p> +<hr/></blockquote><h3 align="center">Apache HTTP Server Version 2.0</h3><a href="./"><img src="../images/index.gif" alt="Index"/></a><a href="../"><img src="../images/home.gif" alt="Home"/></a></body></html>
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