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| author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-27 06:33:50 +0000 |
|---|---|---|
| committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-27 06:33:50 +0000 |
| commit | fe39ffb8b90ae4e002ed73fe98617cd590abb467 (patch) | |
| tree | b80e5956907d8aeaaffe4e4f0c068c0e6157ce8b /docs/manual/developer/modules.html.en | |
| parent | Initial commit. (diff) | |
| download | apache2-fe39ffb8b90ae4e002ed73fe98617cd590abb467.tar.xz apache2-fe39ffb8b90ae4e002ed73fe98617cd590abb467.zip | |
Adding upstream version 2.4.56.upstream/2.4.56
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'docs/manual/developer/modules.html.en')
| -rw-r--r-- | docs/manual/developer/modules.html.en | 306 |
1 files changed, 306 insertions, 0 deletions
diff --git a/docs/manual/developer/modules.html.en b/docs/manual/developer/modules.html.en new file mode 100644 index 0000000..fb7ccef --- /dev/null +++ b/docs/manual/developer/modules.html.en @@ -0,0 +1,306 @@ +<?xml version="1.0" encoding="UTF-8"?> +<!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> +<meta content="text/html; charset=UTF-8" http-equiv="Content-Type" /> +<!-- + XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX + This file is generated from xml source: DO NOT EDIT + XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX + --> +<title>Converting Modules from Apache 1.3 to Apache 2.0 - Apache HTTP Server Version 2.4</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 rel="stylesheet" type="text/css" href="../style/css/prettify.css" /> +<script src="../style/scripts/prettify.min.js" type="text/javascript"> +</script> + +<link href="../images/favicon.ico" rel="shortcut icon" /></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="http://wiki.apache.org/httpd/FAQ">FAQ</a> | <a href="../glossary.html">Glossary</a> | <a href="../sitemap.html">Sitemap</a></p> +<p class="apache">Apache HTTP Server Version 2.4</p> +<img alt="" src="../images/feather.png" /></div> +<div class="up"><a href="./"><img title="<-" alt="<-" src="../images/left.gif" /></a></div> +<div id="path"> +<a href="http://www.apache.org/">Apache</a> > <a href="http://httpd.apache.org/">HTTP Server</a> > <a href="http://httpd.apache.org/docs/">Documentation</a> > <a href="../">Version 2.4</a> > <a href="./">Developer Documentation</a></div><div id="page-content"><div id="preamble"><h1>Converting Modules from Apache 1.3 to Apache 2.0</h1> +<div class="toplang"> +<p><span>Available Languages: </span><a href="../en/developer/modules.html" title="English"> en </a> | +<a href="../ja/developer/modules.html" hreflang="ja" rel="alternate" title="Japanese"> ja </a></p> +</div> + + <p>This is a first attempt at writing the lessons I learned + when trying to convert the <code>mod_mmap_static</code> module to Apache + 2.0. It's by no means definitive and probably won't even be + correct in some ways, but it's a start.</p> +</div> +<div id="quickview"><a href="https://www.apache.org/foundation/contributing.html" class="badge"><img src="https://www.apache.org/images/SupportApache-small.png" alt="Support Apache!" /></a><ul id="toc"><li><img alt="" src="../images/down.gif" /> <a href="#easy">The easier changes ...</a></li> +<li><img alt="" src="../images/down.gif" /> <a href="#messy">The messier changes...</a></li> +</ul><h3>See also</h3><ul class="seealso"><li><a href="#comments_section">Comments</a></li></ul></div> +<div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div> +<div class="section"> +<h2><a name="easy" id="easy">The easier changes ...</a></h2> + + <h3><a name="cleanup" id="cleanup">Cleanup Routines</a></h3> + <p>These now need to be of type <code>apr_status_t</code> and return a + value of that type. Normally the return value will be + <code>APR_SUCCESS</code> unless there is some need to signal an error in + the cleanup. Be aware that even though you signal an error not all code + yet checks and acts upon the error.</p> + + + <h3><a name="init" id="init">Initialisation Routines</a></h3> + <p>These should now be renamed to better signify where they sit + in the overall process. So the name gets a small change from + <code>mmap_init</code> to <code>mmap_post_config</code>. The arguments + passed have undergone a radical change and now look like</p> + + <ul> + <li><code>apr_pool_t *p</code></li> + <li><code>apr_pool_t *plog</code></li> + <li><code>apr_pool_t *ptemp</code></li> + <li><code>server_rec *s</code></li> + </ul> + + + <h3><a name="datatypes" id="datatypes">Data Types</a></h3> + <p>A lot of the data types have been moved into the <a href="http://apr.apache.org/">APR</a>. This means that some have had + a name change, such as the one shown above. The following is a brief + list of some of the changes that you are likely to have to make.</p> + + <ul> + <li><code>pool</code> becomes <code>apr_pool_t</code></li> + <li><code>table</code> becomes <code>apr_table_t</code></li> + </ul> + +</div><div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div> +<div class="section"> +<h2><a name="messy" id="messy">The messier changes...</a></h2> + + <h3><a name="register-hooks" id="register-hooks">Register Hooks</a></h3> + <p>The new architecture uses a series of hooks to provide for + calling your functions. These you'll need to add to your module + by way of a new function, <code>static void register_hooks(void)</code>. + The function is really reasonably straightforward once you + understand what needs to be done. Each function that needs + calling at some stage in the processing of a request needs to + be registered, handlers do not. There are a number of phases + where functions can be added, and for each you can specify with + a high degree of control the relative order that the function + will be called in.</p> + + <p>This is the code that was added to <code>mod_mmap_static</code>:</p> + <div class="example"><pre>static void register_hooks(void) +{ + static const char * const aszPre[]={ "http_core.c",NULL }; + ap_hook_post_config(mmap_post_config,NULL,NULL,HOOK_MIDDLE); + ap_hook_translate_name(mmap_static_xlat,aszPre,NULL,HOOK_LAST); +};</pre></div> + + <p>This registers 2 functions that need to be called, one in + the <code>post_config</code> stage (virtually every module will need this + one) and one for the <code>translate_name</code> phase. note that while + there are different function names the format of each is + identical. So what is the format?</p> + + <div class="example"><p><code> + ap_hook_<var>phase_name</var>(<var>function_name</var>, + <var>predecessors</var>, <var>successors</var>, <var>position</var>); + </code></p></div> + + <p>There are 3 hook positions defined...</p> + + <ul> + <li><code>HOOK_FIRST</code></li> + <li><code>HOOK_MIDDLE</code></li> + <li><code>HOOK_LAST</code></li> + </ul> + + <p>To define the position you use the position and then modify + it with the predecessors and successors. Each of the modifiers + can be a list of functions that should be called, either before + the function is run (predecessors) or after the function has + run (successors).</p> + + <p>In the <code>mod_mmap_static</code> case I didn't care about the + <code>post_config</code> stage, but the <code>mmap_static_xlat</code> + <strong>must</strong> be called after the core module had done its name + translation, hence the use of the aszPre to define a modifier to the + position <code>HOOK_LAST</code>.</p> + + + <h3><a name="moddef" id="moddef">Module Definition</a></h3> + <p>There are now a lot fewer stages to worry about when + creating your module definition. The old definition looked + like</p> + + <div class="example"><pre>module MODULE_VAR_EXPORT <var>module_name</var>_module = +{ + STANDARD_MODULE_STUFF, + /* initializer */ + /* dir config creater */ + /* dir merger --- default is to override */ + /* server config */ + /* merge server config */ + /* command handlers */ + /* handlers */ + /* filename translation */ + /* check_user_id */ + /* check auth */ + /* check access */ + /* type_checker */ + /* fixups */ + /* logger */ + /* header parser */ + /* child_init */ + /* child_exit */ + /* post read-request */ +};</pre></div> + + <p>The new structure is a great deal simpler...</p> + <div class="example"><pre>module MODULE_VAR_EXPORT <var>module_name</var>_module = +{ + STANDARD20_MODULE_STUFF, + /* create per-directory config structures */ + /* merge per-directory config structures */ + /* create per-server config structures */ + /* merge per-server config structures */ + /* command handlers */ + /* handlers */ + /* register hooks */ +};</pre></div> + + <p>Some of these read directly across, some don't. I'll try to + summarise what should be done below.</p> + + <p>The stages that read directly across :</p> + + <dl> + <dt><code>/* dir config creater */</code></dt> + <dd><code>/* create per-directory config structures */</code></dd> + + <dt><code>/* server config */</code></dt> + <dd><code>/* create per-server config structures */</code></dd> + + <dt><code>/* dir merger */</code></dt> + <dd><code>/* merge per-directory config structures */</code></dd> + + <dt><code>/* merge server config */</code></dt> + <dd><code>/* merge per-server config structures */</code></dd> + + <dt><code>/* command table */</code></dt> + <dd><code>/* command apr_table_t */</code></dd> + + <dt><code>/* handlers */</code></dt> + <dd><code>/* handlers */</code></dd> + </dl> + + <p>The remainder of the old functions should be registered as + hooks. There are the following hook stages defined so + far...</p> + + <dl> + <dt><code>ap_hook_pre_config</code></dt> + <dd>do any setup required prior to processing configuration + directives</dd> + + <dt><code>ap_hook_check_config</code></dt> + <dd>review configuration directive interdependencies</dd> + + <dt><code>ap_hook_test_config</code></dt> + <dd>executes only with <code>-t</code> option</dd> + + <dt><code>ap_hook_open_logs</code></dt> + <dd>open any specified logs</dd> + + <dt><code>ap_hook_post_config</code></dt> + <dd>this is where the old <code>_init</code> routines get + registered</dd> + + <dt><code>ap_hook_http_method</code></dt> + <dd>retrieve the http method from a request. (legacy)</dd> + + <dt><code>ap_hook_auth_checker</code></dt> + <dd>check if the resource requires authorization</dd> + + <dt><code>ap_hook_access_checker</code></dt> + <dd>check for module-specific restrictions</dd> + + <dt><code>ap_hook_check_user_id</code></dt> + <dd>check the user-id and password</dd> + + <dt><code>ap_hook_default_port</code></dt> + <dd>retrieve the default port for the server</dd> + + <dt><code>ap_hook_pre_connection</code></dt> + <dd>do any setup required just before processing, but after + accepting</dd> + + <dt><code>ap_hook_process_connection</code></dt> + <dd>run the correct protocol</dd> + + <dt><code>ap_hook_child_init</code></dt> + <dd>call as soon as the child is started</dd> + + <dt><code>ap_hook_create_request</code></dt> + <dd>??</dd> + + <dt><code>ap_hook_fixups</code></dt> + <dd>last chance to modify things before generating content</dd> + + <dt><code>ap_hook_handler</code></dt> + <dd>generate the content</dd> + + <dt><code>ap_hook_header_parser</code></dt> + <dd>lets modules look at the headers, not used by most modules, because + they use <code>post_read_request</code> for this</dd> + + <dt><code>ap_hook_insert_filter</code></dt> + <dd>to insert filters into the filter chain</dd> + + <dt><code>ap_hook_log_transaction</code></dt> + <dd>log information about the request</dd> + + <dt><code>ap_hook_optional_fn_retrieve</code></dt> + <dd>retrieve any functions registered as optional</dd> + + <dt><code>ap_hook_post_read_request</code></dt> + <dd>called after reading the request, before any other phase</dd> + + <dt><code>ap_hook_quick_handler</code></dt> + <dd>called before any request processing, used by cache modules.</dd> + + <dt><code>ap_hook_translate_name</code></dt> + <dd>translate the URI into a filename</dd> + + <dt><code>ap_hook_type_checker</code></dt> + <dd>determine and/or set the doc type</dd> + </dl> + +</div></div> +<div class="bottomlang"> +<p><span>Available Languages: </span><a href="../en/developer/modules.html" title="English"> en </a> | +<a href="../ja/developer/modules.html" hreflang="ja" rel="alternate" title="Japanese"> ja </a></p> +</div><div class="top"><a href="#page-header"><img src="../images/up.gif" alt="top" /></a></div><div class="section"><h2><a id="comments_section" name="comments_section">Comments</a></h2><div class="warning"><strong>Notice:</strong><br />This is not a Q&A section. Comments placed here should be pointed towards suggestions on improving the documentation or server, and may be removed by our moderators if they are either implemented or considered invalid/off-topic. Questions on how to manage the Apache HTTP Server should be directed at either our IRC channel, #httpd, on Libera.chat, or sent to our <a href="https://httpd.apache.org/lists.html">mailing lists</a>.</div> +<script type="text/javascript"><!--//--><![CDATA[//><!-- +var comments_shortname = 'httpd'; +var comments_identifier = 'http://httpd.apache.org/docs/2.4/developer/modules.html'; +(function(w, d) { + if (w.location.hostname.toLowerCase() == "httpd.apache.org") { + d.write('<div id="comments_thread"><\/div>'); + var s = d.createElement('script'); + s.type = 'text/javascript'; + s.async = true; + s.src = 'https://comments.apache.org/show_comments.lua?site=' + comments_shortname + '&page=' + comments_identifier; + (d.getElementsByTagName('head')[0] || d.getElementsByTagName('body')[0]).appendChild(s); + } + else { + d.write('<div id="comments_thread">Comments are disabled for this page at the moment.<\/div>'); + } +})(window, document); +//--><!]]></script></div><div id="footer"> +<p class="apache">Copyright 2023 The Apache Software Foundation.<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="http://wiki.apache.org/httpd/FAQ">FAQ</a> | <a href="../glossary.html">Glossary</a> | <a href="../sitemap.html">Sitemap</a></p></div><script type="text/javascript"><!--//--><![CDATA[//><!-- +if (typeof(prettyPrint) !== 'undefined') { + prettyPrint(); +} +//--><!]]></script> +</body></html>
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