Update filter documentation page.

git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@332971 13f79535-47bb-0310-9956-ffa450edef68
author: Nick Kew <niq@apache.org> 2005-11-13 13:15:48 +0100
committer: Nick Kew <niq@apache.org> 2005-11-13 13:15:48 +0100
commit: c4d662ec071cb3a377772f116b3562867b0d6957 (patch)
tree: 6d9ae7996e2a9e2e156053f1c2256976961bd2de /docs
parent: update transformation (diff)
download: apache2-c4d662ec071cb3a377772f116b3562867b0d6957.tar.xz
apache2-c4d662ec071cb3a377772f116b3562867b0d6957.zip
4 files changed, 178 insertions, 68 deletions
diff --git a/docs/manual/filter.html.en b/docs/manual/filter.html.en
index afb56efbe0..b7459163ae 100644
--- a/docs/manual/filter.html.en
+++ b/docs/manual/filter.html.en
@@ -1,20 +1,20 @@
 <?xml version="1.0" encoding="ISO-8859-1"?>
 <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
-<html xmlns="http://www.w3.org/1999/xhtml" lang="en" xml:lang="en"><head><!--
+<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en"><head><meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1" /><!--
         XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
               This file is generated from xml source: DO NOT EDIT
         XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
       -->
 <title>Filters - Apache HTTP Server</title>
-<link href="./style/css/manual.css" rel="stylesheet" media="all" type="text/css" title="Main stylesheet" />
-<link href="./style/css/manual-loose-100pc.css" rel="alternate stylesheet" media="all" type="text/css" title="No Sidebar - Default font size" />
-<link href="./style/css/manual-print.css" rel="stylesheet" media="print" type="text/css" />
-<link href="./images/favicon.ico" rel="shortcut icon" /></head>
-<body id="manual-page" class="no-sidebar"><div id="page-header">
+<link title="Main stylesheet" type="text/css" media="all" rel="stylesheet" href="./style/css/manual.css" />
+<link title="No Sidebar - Default font size" type="text/css" media="all" rel="alternate stylesheet" href="./style/css/manual-loose-100pc.css" />
+<link type="text/css" media="print" rel="stylesheet" href="./style/css/manual-print.css" />
+<link rel="shortcut icon" href="./images/favicon.ico" /></head>
+<body id="manual-page"><div id="page-header">
 <p class="menu"><a href="./mod/">Modules</a> | <a href="./mod/directives.html">Directives</a> | <a href="./faq/">FAQ</a> | <a href="./glossary.html">Glossary</a> | <a href="./sitemap.html">Sitemap</a></p>
 <p class="apache">Apache HTTP Server Version 2.3</p>
-<img alt="" src="./images/feather.gif" /></div>
-<div class="up"><a href="./"><img title="&lt;-" alt="&lt;-" src="./images/left.gif" /></a></div>
+<img src="./images/feather.gif" alt="" /></div>
+<div class="up"><a href="./"><img src="./images/left.gif" alt="&lt;-" title="&lt;-" /></a></div>
 <div id="path">
 <a href="http://www.apache.org/">Apache</a> &gt; <a href="http://httpd.apache.org/">HTTP Server</a> &gt; <a href="http://httpd.apache.org/docs-project/">Documentation</a> &gt; <a href="./">Version 2.3</a></div><div id="page-content"><div id="preamble"><h1>Filters</h1>
 <div class="toplang">
@@ -27,46 +27,99 @@
 
     <p>This document describes the use of filters in Apache.</p>
   </div>
-<div class="top"><a href="#page-header"><img alt="top" src="./images/up.gif" /></a></div>
+<div id="quickview"><ul id="toc"><li><img src="./images/down.gif" alt="" /> <a href="#intro">Filtering in Apache 2</a></li>
+<li><img src="./images/down.gif" alt="" /> <a href="#smart">Smart Filtering</a></li>
+<li><img src="./images/down.gif" alt="" /> <a href="#using">Using Filters</a></li>
+</ul></div>
+<div class="top"><a href="#page-header"><img src="./images/up.gif" alt="top" /></a></div>
 <div class="section">
-<h2><a name="filters" id="filters">Filters</a></h2>
+<h2><a id="intro" name="intro">Filtering in Apache 2</a></h2>
     
-    <table class="related"><tr><th>Related Modules</th><th>Related Directives</th></tr><tr><td><ul><li><code class="module"><a href="./mod/mod_deflate.html">mod_deflate</a></code></li><li><code class="module"><a href="./mod/mod_ext_filter.html">mod_ext_filter</a></code></li><li><code class="module"><a href="./mod/mod_include.html">mod_include</a></code></li></ul></td><td><ul><li><code class="directive"><a href="./mod/mod_mime.html#addinputfilter">AddInputFilter</a></code></li><li><code class="directive"><a href="./mod/mod_mime.html#addoutputfilter">AddOutputFilter</a></code></li><li><code class="directive"><a href="./mod/mod_mime.html#removeinputfilter">RemoveInputFilter</a></code></li><li><code class="directive"><a href="./mod/mod_mime.html#removeoutputfilter">RemoveOutputFilter</a></code></li><li><code class="directive"><a href="./mod/mod_ext_filter.html#extfilterdefine">ExtFilterDefine</a></code></li><li><code class="directive"><a href="./mod/mod_ext_filter.html#extfilteroptions">ExtFilterOptions</a></code></li><li><code class="directive"><a href="./mod/core.html#setinputfilter">SetInputFilter</a></code></li><li><code class="directive"><a href="./mod/core.html#setoutputfilter">SetOutputFilter</a></code></li></ul></td></tr></table>
+    <table class="related"><tr><th>Related Modules</th><th>Related Directives</th></tr><tr><td><ul><li><code class="module"><a href="./mod/mod_filter.html">mod_filter</a></code></li><li><code class="module"><a href="./mod/mod_deflate.html">mod_deflate</a></code></li><li><code class="module"><a href="./mod/mod_ext_filter.html">mod_ext_filter</a></code></li><li><code class="module"><a href="./mod/mod_include.html">mod_include</a></code></li><li><code class="module"><a href="./mod/mod_charset_lite.html">mod_charset_lite</a></code></li></ul></td><td><ul><li><code class="directive"><a href="./mod/mod_filter.html#filterchain">FilterChain</a></code></li><li><code class="directive"><a href="./mod/mod_filter.html#filterdeclare">FilterDeclare</a></code></li><li><code class="directive"><a href="./mod/mod_filter.html#filterprotocol">FilterProtocol</a></code></li><li><code class="directive"><a href="./mod/mod_filter.html#filterprovider">FilterProvider</a></code></li><li><code class="directive"><a href="./mod/mod_mime.html#addinputfilter">AddInputFilter</a></code></li><li><code class="directive"><a href="./mod/mod_mime.html#addoutputfilter">AddOutputFilter</a></code></li><li><code class="directive"><a href="./mod/mod_mime.html#removeinputfilter">RemoveInputFilter</a></code></li><li><code class="directive"><a href="./mod/mod_mime.html#removeoutputfilter">RemoveOutputFilter</a></code></li><li><code class="directive"><a href="./mod/mod_ext_filter.html#extfilterdefine">ExtFilterDefine</a></code></li><li><code class="directive"><a href="./mod/mod_ext_filter.html#extfilteroptions">ExtFilterOptions</a></code></li><li><code class="directive"><a href="./mod/core.html#setinputfilter">SetInputFilter</a></code></li><li><code class="directive"><a href="./mod/core.html#setoutputfilter">SetOutputFilter</a></code></li></ul></td></tr></table>
 
-    <p>A <em>filter</em> is a process that is applied to data that
-    is sent or received by the server. Data sent by clients to the
-    server is processed by <em>input filters</em> while data sent
-    by the server to the client is processed by <em>output
-    filters</em>. Multiple filters can be applied to the data, and
-    the order of the filters can be explicitly specified.</p>
+<p>The Filter Chain is available in Apache 2.0 and higher,
+and enables applications to process incoming and outgoing data
+in a highly flexible and configurable manner, regardless of
+where the data comes from.  We can pre-process incoming data,
+and post-process outgoing data, at will.  This is basically
+independent of the traditional request processing phases.</p>
+<p class="figure">
+<img src="images/filter_arch.png" width="569" height="392" alt="Filters can be chained, in a Data Axis orthogonal to request processing" />
+</p>
+<p>Some examples of filtering in the standard Apache distribution are:</p>
+<ul>
+<li>mod_includes, implements server-side includes.</li>
+<li>mod_ssl, implements SSL encryption (https).</li>
+<li>mod_deflate, implements compression/decompression on the fly.</li>
+<li>mod_charset_lite, transcodes between different character sets.</li>
+<li>mod_ext_filter, runs an external program as a filter.</li>
+</ul>
+<p>Apache also uses a number of filters internally, to perform
+functions like chunking and byte-range handling.</p>
 
-    <p>Filters are used internally by Apache to perform functions such
-    as chunking and byte-range request handling. In addition, modules
-    can provide filters that are selectable using run-time
-    configuration directives. The set of filters that apply to data
-    can be manipulated with the
+<p>A wider range of applications are implemented by third-party
+filter modules.  A few of these are:</p>
+<ul>
+<li>HTML and XML processing and rewriting</li>
+<li>XSLT transforms and XIncludes</li>
+<li>XML Namespace support</li>
+<li>File Upload handling and decoding of HTML Forms</li>
+<li>Image processing</li>
+<li>Protection of vulnerable applications such as PHP scripts</li>
+<li>Text search-and-replace editing</li>
+</ul>
+</div><div class="top"><a href="#page-header"><img src="./images/up.gif" alt="top" /></a></div>
+<div class="section">
+<h2><a id="smart" name="smart">Smart Filtering</a></h2>
+
+<p class="figure">
+<img src="images/mod_filter_new.png" width="423" height="331" alt="Smart filtering applies different filter providers according to the state of request processing" />
+</p>
+<p><code class="module"><a href="./mod/mod_filter.html">mod_filter</a></code>, included in Apache 2.1 and up,
+enables the filter chain to be configured dynamically at run time.
+So for example you can set up a proxy to rewrite
+HTML with an HTML filter and JPEG images with a completely
+separate filter, despite the proxy having no prior information
+about what the origin server will send.  This works by using a
+filter harness, that dispatches to different providers according
+to the actual contents at runtime.  Any filter may be either
+inserted directly in the chain and run unconditionally, or
+used as a provider and inserted dynamically.  For example,</p>
+<ul>
+<li>an HTML processing filter will only run if the content is
+text/html or application/xhtml+xml</li>
+<li>A compression filter will only run if the input is a
+compressable type and not already compressed</li>
+<li>A charset conversion filter will be inserted if a text
+document is not already in the desired charset</li>
+</ul>
+</div><div class="top"><a href="#page-header"><img src="./images/up.gif" alt="top" /></a></div>
+<div class="section">
+<h2><a id="using" name="using">Using Filters</a></h2>
+
+<p>There are two ways to use filtering: Simple and Dynamic.
+In general, you should use one or the other: mixing them can
+have unexpected consequences (although simple Input filtering
+can be mixed freely with either simple or dynamic Output filtering!</p>
+<p>The Simple Way is the only way to configure input filters, and is
+suficient for output filters where you need a static filter chain.
+Relevant directives are
     <code class="directive"><a href="./mod/core.html#setinputfilter">SetInputFilter</a></code>,
     <code class="directive"><a href="./mod/core.html#setoutputfilter">SetOutputFilter</a></code>,
     <code class="directive"><a href="./mod/mod_mime.html#addinputfilter">AddInputFilter</a></code>,
     <code class="directive"><a href="./mod/mod_mime.html#addoutputfilter">AddOutputFilter</a></code>,
     <code class="directive"><a href="./mod/mod_mime.html#removeinputfilter">RemoveInputFilter</a></code>, and
-    <code class="directive"><a href="./mod/mod_mime.html#removeoutputfilter">RemoveOutputFilter</a></code>
-    directives.</p>
-
-    <p>The following user-selectable filters are currently provided
-    with the Apache HTTP Server distribution.</p>
-
-    <dl>
-      <dt>INCLUDES</dt>
-      <dd>Server-Side Includes processing by <code class="module"><a href="./mod/mod_include.html">mod_include</a></code></dd>
-      <dt>DEFLATE</dt>
-      <dd>Compress output before sending it to the client using
-          <code class="module"><a href="./mod/mod_deflate.html">mod_deflate</a></code>
-      </dd>
-    </dl>
+    <code class="directive"><a href="./mod/mod_mime.html#removeoutputfilter">RemoveOutputFilter</a></code>.</p>
 
-    <p>In addition, the module <code class="module"><a href="./mod/mod_ext_filter.html">mod_ext_filter</a></code> allows
-    for external programs to be defined as filters.</p>
+<p>The Dynamic Way enables both static and flexible, dynamic configuration
+of output filters, as discussed in the <code class="module"><a href="./mod/mod_filter.html">mod_filter</a></code> page.
+Relevant directives are
+    <code class="directive"><a href="./mod/mod_filter.html#filterchain">FilterChain</a></code>,
+    <code class="directive"><a href="./mod/mod_filter.html#filterdeclare">FilterDeclare</a></code>,
+    <code class="directive"><a href="./mod/mod_filter.html#filterprovider">FilterProvider</a></code>.</p>
+<p>One further directive AddOutputFilterByType is still supported,
+but may be problematic and is now deprecated.  Use dynamic configuration
+instead.</p>
   </div></div>
 <div class="bottomlang">
 <p><span>Available Languages: </span><a href="./en/filter.html" title="English">&nbsp;en&nbsp;</a> |
@@ -77,4 +130,4 @@
 </div><div id="footer">
 <p class="apache">Copyright 1995-2005 The Apache Software Foundation or its licensors, as applicable.<br />Licensed under the <a href="http://www.apache.org/licenses/LICENSE-2.0">Apache License, Version 2.0</a>.</p>
 <p class="menu"><a href="./mod/">Modules</a> | <a href="./mod/directives.html">Directives</a> | <a href="./faq/">FAQ</a> | <a href="./glossary.html">Glossary</a> | <a href="./sitemap.html">Sitemap</a></p></div>
-</body></html>
-\ No newline at end of file
+</body></html>
diff --git a/docs/manual/filter.xml b/docs/manual/filter.xml
index e5de3c0bfb..2d58be5120 100644
--- a/docs/manual/filter.xml
+++ b/docs/manual/filter.xml
@@ -28,15 +28,21 @@
     <p>This document describes the use of filters in Apache.</p>
   </summary>
 
-  <section id="filters">
-    <title>Filters</title>
+  <section id="intro">
+    <title>Filtering in Apache 2</title>
     <related>
       <modulelist>
+	<module>mod_filter</module>
         <module>mod_deflate</module>
         <module>mod_ext_filter</module>
         <module>mod_include</module>
+	<module>mod_charset_lite</module>
       </modulelist>
       <directivelist>
+        <directive module="mod_filter">FilterChain</directive>
+        <directive module="mod_filter">FilterDeclare</directive>
+        <directive module="mod_filter">FilterProtocol</directive>
+        <directive module="mod_filter">FilterProvider</directive>
         <directive module="mod_mime">AddInputFilter</directive>
         <directive module="mod_mime">AddOutputFilter</directive>
         <directive module="mod_mime">RemoveInputFilter</directive>
@@ -48,39 +54,90 @@
       </directivelist>
     </related>
 
-    <p>A <em>filter</em> is a process that is applied to data that
-    is sent or received by the server. Data sent by clients to the
-    server is processed by <em>input filters</em> while data sent
-    by the server to the client is processed by <em>output
-    filters</em>. Multiple filters can be applied to the data, and
-    the order of the filters can be explicitly specified.</p>
+<p>The Filter Chain is available in Apache 2.0 and higher,
+and enables applications to process incoming and outgoing data
+in a highly flexible and configurable manner, regardless of
+where the data comes from.  We can pre-process incoming data,
+and post-process outgoing data, at will.  This is basically
+independent of the traditional request processing phases.</p>
+<p class="figure">
+<img src="images/filter_arch.png" width="569" height="392" alt=
+"Filters can be chained, in a Data Axis orthogonal to request processing"
+/>
+</p>
+<p>Some examples of filtering in the standard Apache distribution are:</p>
+<ul>
+<li>mod_includes, implements server-side includes.</li>
+<li>mod_ssl, implements SSL encryption (https).</li>
+<li>mod_deflate, implements compression/decompression on the fly.</li>
+<li>mod_charset_lite, transcodes between different character sets.</li>
+<li>mod_ext_filter, runs an external program as a filter.</li>
+</ul>
+<p>Apache also uses a number of filters internally, to perform
+functions like chunking and byte-range handling.</p>
 
-    <p>Filters are used internally by Apache to perform functions such
-    as chunking and byte-range request handling. In addition, modules
-    can provide filters that are selectable using run-time
-    configuration directives. The set of filters that apply to data
-    can be manipulated with the
+<p>A wider range of applications are implemented by third-party
+filter modules.  A few of these are:</p>
+<ul>
+<li>HTML and XML processing and rewriting</li>
+<li>XSLT transforms and XIncludes</li>
+<li>XML Namespace support</li>
+<li>File Upload handling and decoding of HTML Forms</li>
+<li>Image processing</li>
+<li>Protection of vulnerable applications such as PHP scripts</li>
+<li>Text search-and-replace editing</li>
+</ul>
+</section>
+<section id="smart">
+<title>Smart Filtering</title>
+<p class="figure">
+<img src="images/mod_filter_new.png" width="423" height="331"
+alt="Smart filtering applies different filter providers according to the state of request processing"/>
+</p>
+<p><module>mod_filter</module>, included in Apache 2.1 and up,
+enables the filter chain to be configured dynamically at run time.
+So for example you can set up a proxy to rewrite
+HTML with an HTML filter and JPEG images with a completely
+separate filter, despite the proxy having no prior information
+about what the origin server will send.  This works by using a
+filter harness, that dispatches to different providers according
+to the actual contents at runtime.  Any filter may be either
+inserted directly in the chain and run unconditionally, or
+used as a provider and inserted dynamically.  For example,</p>
+<ul>
+<li>an HTML processing filter will only run if the content is
+text/html or application/xhtml+xml</li>
+<li>A compression filter will only run if the input is a
+compressable type and not already compressed</li>
+<li>A charset conversion filter will be inserted if a text
+document is not already in the desired charset</li>
+</ul>
+</section>
+
+<section id="using">
+<title>Using Filters</title>
+<p>There are two ways to use filtering: Simple and Dynamic.
+In general, you should use one or the other: mixing them can
+have unexpected consequences (although simple Input filtering
+can be mixed freely with either simple or dynamic Output filtering!</p>
+<p>The Simple Way is the only way to configure input filters, and is
+suficient for output filters where you need a static filter chain.
+Relevant directives are
     <directive module="core">SetInputFilter</directive>,
     <directive module="core">SetOutputFilter</directive>,
     <directive module="mod_mime">AddInputFilter</directive>,
     <directive module="mod_mime">AddOutputFilter</directive>,
     <directive module="mod_mime">RemoveInputFilter</directive>, and
-    <directive module="mod_mime">RemoveOutputFilter</directive>
-    directives.</p>
-
-    <p>The following user-selectable filters are currently provided
-    with the Apache HTTP Server distribution.</p>
-
-    <dl>
-      <dt>INCLUDES</dt>
-      <dd>Server-Side Includes processing by <module>mod_include</module></dd>
-      <dt>DEFLATE</dt>
-      <dd>Compress output before sending it to the client using
-          <module>mod_deflate</module>
-      </dd>
-    </dl>
+    <directive module="mod_mime">RemoveOutputFilter</directive>.</p>
 
-    <p>In addition, the module <module>mod_ext_filter</module> allows
-    for external programs to be defined as filters.</p>
+<p>The Dynamic Way enables both static and flexible, dynamic configuration
+of output filters, as discussed in the <module>mod_filter</module> page.
+Relevant directives are
+    <directive module="mod_filter">FilterChain</directive>,
+    <directive module="mod_filter">FilterDeclare</directive>,
+    <directive module="mod_filter">FilterProvider</directive>.</p>
+<p>One further directive AddOutputFilterByType is still supported,
+but may be problematic and is now deprecated.  Use dynamic configuration
+instead.</p>
   </section>
 </manualpage>
diff --git a/docs/manual/images/filter_arch.png b/docs/manual/images/filter_arch.png
new file mode 100644
index 0000000000..de021af5b5
--- /dev/null
+++ b/docs/manual/images/filter_arch.png
diff --git a/docs/manual/images/mod_filter_new.png b/docs/manual/images/mod_filter_new.png
new file mode 100644
index 0000000000..ad2cc73599
--- /dev/null
+++ b/docs/manual/images/mod_filter_new.png
author	Nick Kew <niq@apache.org>	2005-11-13 13:15:48 +0100
committer	Nick Kew <niq@apache.org>	2005-11-13 13:15:48 +0100
commit	c4d662ec071cb3a377772f116b3562867b0d6957 (patch)
tree	6d9ae7996e2a9e2e156053f1c2256976961bd2de /docs
parent	update transformation (diff)
download	apache2-c4d662ec071cb3a377772f116b3562867b0d6957.tar.xz apache2-c4d662ec071cb3a377772f116b3562867b0d6957.zip