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| <manualpage metafile="new_features_2_2.xml.meta"> |
| |
| <title>Overview of new features in Apache HTTP Server 2.2</title> |
| |
| <summary> |
| <p>This document describes some of the major changes between the |
| 2.0 and 2.2 versions of the Apache HTTP Server. For new features since |
| version 1.3, see the <a href="new_features_2_0.html">2.0 new features</a> |
| document.</p> |
| </summary> |
| |
| <section id="core"> |
| <title>Core Enhancements</title> |
| <dl> |
| |
| <dt>Authn/Authz</dt> |
| <dd>The bundled authentication and authorization modules have |
| been refactored. The new mod_authn_alias(already removed from 2.3/2.4) |
| module can greatly simplify certain authentication configurations. |
| See <a href="#module">module name changes</a>, and |
| <a href="#developer">the developer changes</a> for more |
| information about how these changes affects users and module |
| writers.</dd> |
| |
| <dt>Caching</dt> |
| <dd><module>mod_cache</module>, <module>mod_cache_disk</module>, and |
| mod_mem_cache(already removed from 2.3/2.4) have undergone a lot of changes, and |
| are now considered production-quality. <program>htcacheclean</program> |
| has been introduced to clean up <module>mod_cache_disk</module> |
| setups.</dd> |
| |
| <dt>Configuration</dt> |
| <dd>The default configuration layout has been simplified and |
| modularised. Configuration snippets which can be used to |
| enable commonly-used features are now bundled with Apache, and |
| can be easily added to the main server config.</dd> |
| |
| <dt>Graceful stop</dt> |
| <dd>The <module>prefork</module>, <module>worker</module> and |
| <module>event</module> MPMs now allow <program>httpd</program> |
| to be shutdown gracefully via the |
| <a href="stopping.html#gracefulstop"><code>graceful-stop</code></a> |
| signal. The <directive |
| module="mpm_common">GracefulShutdownTimeout</directive> directive |
| has been added to specify an optional timeout, after which |
| <program>httpd</program> will terminate regardless of the status |
| of any requests being served.</dd> |
| |
| <dt>Proxying</dt> |
| <dd>The new <module>mod_proxy_balancer</module> module provides |
| load balancing services for <module>mod_proxy</module>. |
| The new <module>mod_proxy_ajp</module> module adds support for the |
| <code>Apache JServ Protocol version 1.3</code> used by |
| <a href="http://tomcat.apache.org/">Apache Tomcat</a>.</dd> |
| |
| <dt>Regular Expression Library Updated</dt> |
| <dd>Version 5.0 of the |
| <a href="http://www.pcre.org/">Perl Compatible Regular Expression |
| Library</a> (PCRE) is now included. <program>httpd</program> can be |
| configured to use a system installation of PCRE by passing the |
| <code>--with-pcre</code> flag to configure.</dd> |
| |
| <dt>Smart Filtering</dt> |
| <dd><module>mod_filter</module> introduces dynamic configuration |
| to the output filter chain. It enables filters to be conditionally |
| inserted, based on any Request or Response header or environment |
| variable, and dispenses with the more problematic dependencies and |
| ordering problems in the 2.0 architecture.</dd> |
| |
| <dt>Large File Support</dt> |
| <dd><program>httpd</program> is now built with support for files larger |
| than 2GB on modern 32-bit Unix systems. Support for handling |
| >2GB request bodies has also been added.</dd> |
| |
| <dt>Event MPM</dt> |
| <dd>The <module>event</module> MPM uses a separate thread to handle |
| Keep Alive requests and accepting connections. Keep Alive requests |
| have traditionally required httpd to dedicate a worker to handle it. |
| This dedicated worker could not be used again until the Keep Alive |
| timeout was reached.</dd> |
| |
| <dt>SQL Database Support</dt> |
| <dd><module>mod_dbd</module>, together with the <code>apr_dbd</code> |
| framework, brings direct SQL support to modules that need it. |
| Supports connection pooling in threaded MPMs.</dd> |
| |
| </dl> |
| </section> |
| |
| <section id="module"> |
| <title>Module Enhancements</title> |
| <dl> |
| <dt>Authn/Authz</dt> |
| <dd>Modules in the aaa directory have been renamed and offer |
| better support for digest authentication. For example, |
| <code>mod_auth</code> is now split into |
| <module>mod_auth_basic</module> and |
| <module>mod_authn_file</module>; <code>mod_auth_dbm</code> is now |
| called <module>mod_authn_dbm</module>; <code>mod_access</code> has |
| been renamed <module>mod_authz_host</module>. There is also a new |
| mod_authn_alias(already removed from 2.3/2.4) module for simplifying |
| certain authentication configurations. |
| </dd> |
| |
| <dt><module outdated="true">mod_authnz_ldap</module></dt> |
| <dd>This module is a port of the 2.0 |
| <code>mod_auth_ldap</code> module to the 2.2 <code>Authn/Authz</code> |
| framework. New features include using LDAP attribute values and |
| complicated search filters in the |
| <directive module="mod_authz_core">Require</directive> directive.</dd> |
| |
| <dt><module>mod_authz_owner</module></dt> |
| <dd>A new module that authorizes access to files based |
| on the owner of the file on the file system</dd> |
| |
| <dt><module>mod_version</module></dt> |
| <dd>A new module that allows configuration blocks to be enabled based on the |
| version number of the running server.</dd> |
| |
| <dt><module>mod_info</module></dt> |
| <dd>Added a new <code>?config</code> argument which will show |
| the configuration directives as parsed by Apache, including |
| their file name and line number. The module also |
| shows the order of all request hooks and additional |
| build information, similar to <code>httpd -V</code>.</dd> |
| |
| <dt><module>mod_ssl</module></dt> |
| <!-- Need Info on SSLEngine Support? --> |
| <dd>Added a support for |
| <a href="http://www.ietf.org/rfc/rfc2817.txt">RFC 2817</a>, which |
| allows connections to upgrade from clear text to TLS encryption.</dd> |
| |
| <dt><module>mod_imagemap</module></dt> |
| <dd><code>mod_imap</code> has been renamed to |
| <module>mod_imagemap</module> to avoid user confusion.</dd> |
| </dl> |
| |
| </section> |
| |
| <section id="programs"> |
| <title>Program Enhancements</title> |
| <dl> |
| <dt><program>httpd</program></dt> |
| <dd>A new command line option <code>-M</code> has been added that |
| lists all modules that are loaded based on the current |
| configuration. Unlike the <code>-l</code> option, this list |
| includes DSOs loaded via <module>mod_so</module>.</dd> |
| |
| <dt><program>httxt2dbm</program></dt> |
| <dd>A new program used to generate dbm files from text input, |
| for use in <directive module="mod_rewrite">RewriteMap</directive> |
| with the <code>dbm</code> map type.</dd> |
| </dl> |
| </section> |
| |
| <section id="developer"> |
| <title>Module Developer Changes</title> |
| <dl> |
| <dt><glossary>APR</glossary> 1.0 API</dt> |
| |
| <dd>Apache 2.2 uses the APR 1.0 API. All deprecated functions and |
| symbols have been removed from <code>APR</code> and |
| <code>APR-Util</code>. For details, see the |
| <a href="http://apr.apache.org/">APR Website</a>.</dd> |
| |
| <dt>Authn/Authz</dt> |
| <dd>The bundled authentication and authorization modules have |
| been renamed along the following lines: |
| <ul> |
| <li><code>mod_auth_*</code> -> Modules that implement an HTTP |
| authentication mechanism</li> |
| <li><code>mod_authn_*</code> -> Modules that provide a backend |
| authentication provider</li> |
| <li><code>mod_authz_*</code> -> Modules that implement |
| authorization (or access)</li> |
| <li><code>mod_authnz_*</code> -> Module that implements both |
| authentication & authorization</li> |
| </ul> |
| There is a new authentication backend provider |
| scheme which greatly eases the construction of new authentication |
| backends.</dd> |
| |
| <dt>Connection Error Logging</dt> |
| |
| <dd>A new function, <code>ap_log_cerror</code> has been added to log |
| errors that occur with the client's connection. When logged, |
| the message includes the client IP address.</dd> |
| |
| <dt>Test Configuration Hook Added</dt> |
| |
| <dd>A new hook, <code>test_config</code> has been added to aid |
| modules that want to execute special code only when the user passes |
| <code>-t</code> to <program>httpd</program>.</dd> |
| |
| <dt>Set Threaded MPM's Stacksize</dt> |
| |
| <dd>A new directive, <directive module="mpm_common" |
| >ThreadStackSize</directive> has been added to |
| set the stack size on all threaded MPMs. This is required |
| for some third-party modules on platforms with small default |
| thread stack size.</dd> |
| |
| <dt>Protocol handling for output filters</dt> |
| |
| <dd>In the past, every filter has been responsible for ensuring |
| that it generates the correct response headers where it affects |
| them. Filters can now delegate common protocol management to |
| <module>mod_filter</module>, using the |
| <code>ap_register_output_filter_protocol</code> or |
| <code>ap_filter_protocol</code> calls.</dd> |
| |
| <dt>Monitor hook added</dt> |
| <dd>Monitor hook enables modules to run regular/scheduled jobs |
| in the parent (root) process.</dd> |
| |
| <dt>Regular expression API changes</dt> |
| |
| <dd>The <code>pcreposix.h</code> header is no longer available; |
| it is replaced by the new <code>ap_regex.h</code> header. The |
| POSIX.2 <code>regex.h</code> implementation exposed by the old |
| header is now available under the <code>ap_</code> namespace |
| from <code>ap_regex.h</code>. Calls to <code>regcomp</code>, |
| <code>regexec</code> and so on can be replaced by calls to |
| <code>ap_regcomp</code>, <code>ap_regexec</code>.</dd> |
| |
| <dt>DBD Framework (SQL Database API)</dt> |
| |
| <dd><p>With Apache 1.x and 2.0, modules requiring an SQL backend |
| had to take responsibility for managing it themselves. Apart |
| from reinventing the wheel, this can be very inefficient, for |
| example when several modules each maintain their own connections.</p> |
| |
| <p>Apache 2.1 and later provides the <code>ap_dbd</code> API for |
| managing database connections (including optimised strategies |
| for threaded and unthreaded MPMs), while APR 1.2 and later provides |
| the <code>apr_dbd</code> API for interacting with the database.</p> |
| |
| <p>New modules SHOULD now use these APIs for all SQL database |
| operations. Existing applications SHOULD be upgraded to use it |
| where feasible, either transparently or as a recommended option |
| to their users.</p></dd> |
| </dl> |
| </section> |
| </manualpage> |