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7 Copyright 2004-2005 The Apache Software Foundation or its licensors, as
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23 <manualpage metafile="new_features_2_2.xml.meta">
25 <title>Overview of new features in Apache 2.2</title>
28 <p>This document describes some of the major changes between the
29 2.0 and 2.2 versions of the Apache HTTP Server. For new features since
30 version 1.3, see the <a href="new_features_2_0.html">2.0 new features</a>
35 <title>Core Enhancements</title>
39 <dd>The bundled authentication and authorization modules have
40 been refactored. There is a new authentication backend provider
41 scheme which greatly eases the construction of new authentication
45 <dd><module>mod_cache</module>, <module>mod_disk_cache</module>, and
46 <module>mod_mem_cache</module> have undergone a lot of changes
47 are now considered production-quality. <program>htcacheclean</program>
48 has been introduced to cleanup <module>mod_disk_cache</module>
51 <dt>Graceful stop</dt>
52 <dd>The <module>prefork</module>, <module>worker</module> and
53 <module>event</module> MPMs now allow <program>httpd</program>
54 to be shutdown gracefully via the
55 <a href="stopping.html#gracefulstop"><code>graceful-stop</code></a>
56 signal. The <directive
57 module="mpm_common">GracefulShutdownTimeout</directive> directive
58 has been added to specify an optional timeout, after which
59 <program>httpd</program> will terminate regardless of the status
60 of any requests being served.</dd>
63 <dd>The new <module>mod_proxy_balancer</module> module provides
64 load balancing services for <module>mod_proxy</module>.
65 The new <module>mod_proxy_ajp</module> module adds support for the
66 <code>Apache JServ Protocol version 1.3</code> used by
67 <a href="http://jakarta.apache.org/tomcat/">Apache Tomcat</a>.</dd>
69 <dt>Regular Expression Library Updated</dt>
70 <dd>Version 5.0 of the
71 <a href="http://www.pcre.org/">Perl Compatible Regular Expression
72 Library</a> (PCRE) is now included.</dd>
74 <dt>Smart Filtering</dt>
75 <dd><module>mod_filter</module> introduces dynamic configuration
76 to the output filter chain. It enables filters to be conditionally
77 inserted, based on any Request or Response header or environment
78 variable, and dispenses with the more problematic dependencies and
79 ordering problems in the 2.0 architecture.</dd>
81 <dt>Large File Support</dt>
83 <dd>httpd is now built with support for files larger than 2Gb on
84 modern 32-bit Unix systems. Support for handling >2Gb request
85 bodies has also been added.</dd>
88 <dd>The <module>event</module> MPM uses a seperate thread to handle
89 Keep Alive requests and accepting connections. Keep Alive requests
90 have traditionally required httpd to dedicate a worker to handle it.
91 This dedicated worker could not be used again until the Keep Alive
92 timeout was reached.</dd>
94 <dt>SQL Database Support</dt>
95 <dd><module>mod_dbd</module>, together with the apr_dbd framework,
96 brings direct SQL support to modules that need it. Supports
97 connection pooling in threaded MPMs.</dd>
102 <section id="module">
103 <title>Module Enhancements</title>
105 <dt><module>mod_authnz_ldap</module></dt>
106 <dd>This module is a port of the 2.0
107 <code>mod_auth_ldap</code> module to the 2.2 <code>Authn/Authz</code>
108 framework. New features include using LDAP attribute values and
109 complicated search filters in the
110 <directive module="core">Require</directive> directive.</dd>
112 <dt><module>mod_info</module></dt>
113 <dd>Added a new <code>?config</code> argument which will show
114 the configuration directives as parsed by Apache, including
115 their file name and line number. The module also
116 shows the order of all request hooks and additional
117 build information, similar to <code>httpd -V</code>.</dd>
119 <dt><module>mod_ssl</module></dt>
120 <!-- Need Info on SSLEngine Support? -->
121 <dd>Added a support for
122 <a href="http://www.ietf.org/rfc/rfc2817.txt">RFC 2817</a>, which
123 allows connections to upgrade from clear text to TLS encryption.</dd>
127 <section id="programs">
128 <title>Program Enhancements</title>
130 <dt><program>httpd</program></dt>
131 <dd>A new command line option <code>-M</code> has been added that
132 lists all modules that are loaded based on the current
133 configuration. Unlike the <code>-l</code> option, this list
134 includes DSOs loaded via <module>mod_so</module>.</dd>
138 <section id="developer">
139 <title>Module Developer Changes</title>
143 <dd>Apache 2.2 uses the APR 1.0 API. All deprecated functions and
144 symbols have been removed from <code>APR</code> and
145 <code>APR-Util</code>. For details, see the
146 <a href="http://apr.apache.org/">APR Website</a>.</dd>
148 <dt>Connection Error Logging</dt>
150 <dd>A new function, <code>ap_log_cerror</code> has been added to log
151 errors that occure with the client's connection. When logged,
152 the message includes the client IP address.</dd>
154 <dt>Test Configuration Hook Added</dt>
156 <dd>A new hook, <code>test_config</code> has been added to aid
157 modules that want to execute special code only when the user passes
158 <code>-t</code> to <program>httpd</program>.</dd>
160 <dt>Set Threaded MPM's Stacksize</dt>
162 <dd>A new directive, <code>ThreadStackSize</code> has been added to
163 set the stack size on all threaded MPMs. This is required
164 for some third-party modules on platforms with small default
165 thread stack size.</dd>
167 <dt>Protocol handling for output filters</dt>
169 <dd>In the past, every filter has been responsible for ensuring
170 that it generates the correct response headers where it affects
171 them. Filters can now delegate common protocol management to
172 <module>mod_filter</module>, using the
173 <code>ap_register_output_filter_protocol</code> or
174 <code>ap_filter_protocol</code> calls.</dd>
176 <dt>Monitor hook added</dt>
177 <dd>Monitor hook enables modules to run regular/scheduled jobs
178 in the parent (root) process.</dd>