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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>
52 <dd>The new <module>mod_proxy_balancer</module> module provides
53 load balancing services for <module>mod_proxy</module>.
54 The new <module>mod_proxy_ajp</module> module adds support for the
55 <code>Apache JServ Protocol version 1.3</code> used by
56 <a href="http://jakarta.apache.org/tomcat/">Apache Tomcat</a>.</dd>
58 <dt>Regular Expression Library Updated</dt>
59 <dd>Version 5.0 of the
60 <a href="http://www.pcre.org/">Perl Compatible Regular Expression
61 Library</a> (PCRE) is now included.</dd>
63 <dt>Smart Filtering</dt>
64 <dd><module>mod_filter</module> introduces dynamic configuration
65 to the output filter chain. It enables filters to be conditionally
66 inserted, based on any Request or Response header or environment
67 variable, and dispenses with the more problematic dependencies and
68 ordering problems in the 2.0 architecture.</dd>
70 <dt>Large File Support</dt>
72 <dd>httpd is now built with support for files larger than 2Gb on
73 modern 32-bit Unix systems. Support for handling >2Gb request
74 bodies has also been added.</dd>
77 <dd>The <module>event</module> MPM uses a seperate thread to handle
78 Keep Alive requests and accepting connections. Keep Alive requests
79 have traditionally required httpd to dedicate a worker to handle it.
80 This dedicated worker could not be used again until the Keep Alive
81 timeout was reached.</dd>
83 <dt>SQL Database Support</dt>
84 <dd><module>mod_dbd</module>, together with the apr_dbd framework,
85 brings direct SQL support to modules that need it. Supports
86 connection pooling in threaded MPMs.</dd>
92 <title>Module Enhancements</title>
94 <dt><module>mod_authnz_ldap</module></dt>
95 <dd>This module is a port of the 2.0
96 <code>mod_auth_ldap</code> module to the 2.2 <code>Authn/Authz</code>
97 framework. New features include using LDAP attribute values and
98 complicated search filters in the
99 <directive module="core">Require</directive> directive.</dd>
101 <dt><module>mod_info</module></dt>
102 <dd>Added a new <code>?config</code> argument which will show
103 the configuration directives as parsed by Apache, including
104 their file name and line number. The module also
105 shows the order of all request hooks and additional
106 build information, similar to <code>httpd -V</code>.</dd>
108 <dt><module>mod_ssl</module></dt>
109 <!-- Need Info on SSLEngine Support? -->
110 <dd>Added a support for
111 <a href="http://www.ietf.org/rfc/rfc2817.txt">RFC 2817</a>, which
112 allows connections to upgrade from clear text to TLS encryption.</dd>
116 <section id="programs">
117 <title>Program Enhancements</title>
119 <dt><program>httpd</program></dt>
120 <dd>A new command line option <code>-M</code> has been added that
121 lists all modules that are loaded based on the current
122 configuration. Unlike the <code>-l</code> option, this list
123 includes DSOs loaded via <module>mod_so</module>.</dd>
127 <section id="developer">
128 <title>Module Developer Changes</title>
132 <dd>Apache 2.2 uses the APR 1.0 API. All deprecated functions and
133 symbols have been removed from <code>APR</code> and
134 <code>APR-Util</code>. For details, see the
135 <a href="http://apr.apache.org/">APR Website</a>.</dd>
137 <dt>Connection Error Logging</dt>
139 <dd>A new function, <code>ap_log_cerror</code> has been added to log
140 errors that occure with the client's connection. When logged,
141 the message includes the client IP address.</dd>
143 <dt>Test Configuration Hook Added</dt>
145 <dd>A new hook, <code>test_config</code> has been added to aid
146 modules that want to execute special code only when the user passes
147 <code>-t</code> to <program>httpd</program>.</dd>
149 <dt>Set Threaded MPM's Stacksize</dt>
151 <dd>A new directive, <code>ThreadStackSize</code> has been added to
152 set the stack size on all threaded MPMs. This is required
153 for some third-party modules on platforms with small default
154 thread stack size.</dd>
156 <dt>Protocol handling for output filters</dt>
158 <dd>In the past, every filter has been responsible for ensuring
159 that it generates the correct response headers where it affects
160 them. Filters can now delegate common protocol management to
161 <module>mod_filter</module>, using the
162 <code>ap_register_output_filter_protocol</code> or
163 <code>ap_filter_protocol</code> calls.</dd>
165 <dt>Monitor hook added</dt>
166 <dd>Monitor hook enables modules to run regular/scheduled jobs
167 in the parent (root) process.</dd>