Apache HTTP Сервер Версия 2.2
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Overview of new features in Apache 2.2
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 2.0 new features document.
Core Enhancements
- Authn/Authz
- The bundled authentication and authorization modules have
been refactored. The new
mod_authn_aliasmodule can greatly simplify certain authentication configurations. See module name changes, and the developer changes for more information about how these changes affects users and module writers. - Caching
mod_cache,mod_disk_cache, andmod_mem_cachehave undergone a lot of changes, and are now considered production-quality.htcachecleanhas been introduced to clean upmod_disk_cachesetups.- Configuration
- 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.
- Graceful stop
- The
prefork,workerandeventMPMs now allowhttpdto be shutdown gracefully via thegraceful-stopsignal. TheGracefulShutdownTimeoutdirective has been added to specify an optional timeout, after whichhttpdwill terminate regardless of the status of any requests being served. - Proxying
- The new
mod_proxy_balancermodule provides load balancing services formod_proxy. The newmod_proxy_ajpmodule adds support for theApache JServ Protocol version 1.3used by . - Regular Expression Library Updated
- Version 5.0 of the
(PCRE) is now included.
httpdcan be configured to use a system installation of PCRE by passing the--with-pcreflag to configure. - Smart Filtering
mod_filterintroduces 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.- Large File Support
httpdis 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.- Event MPM
- The
eventMPM 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. - SQL Database Support
mod_dbd, together with theapr_dbdframework, brings direct SQL support to modules that need it. Supports connection pooling in threaded MPMs.
Module Enhancements
- Authn/Authz
- Modules in the aaa directory have been renamed and offer
better support for digest authentication. For example,
mod_authis now split intomod_auth_basicandmod_authn_file;mod_auth_dbmis now calledmod_authn_dbm;mod_accesshas been renamedmod_authz_host. There is also a newmod_authn_aliasmodule for simplifying certain authentication configurations. mod_authnz_ldap- This module is a port of the 2.0
mod_auth_ldapmodule to the 2.2Authn/Authzframework. New features include using LDAP attribute values and complicated search filters in theRequiredirective. mod_authz_owner- A new module that authorizes access to files based on the owner of the file on the file system
mod_version- A new module that allows configuration blocks to be enabled based on the version number of the running server.
mod_info- Added a new
?configargument 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 tohttpd -V. mod_ssl- Added a support for , which allows connections to upgrade from clear text to TLS encryption.
mod_imagemapmod_imaphas been renamed tomod_imagemapto avoid user confusion.
Program Enhancements
httpd- A new command line option
-Mhas been added that lists all modules that are loaded based on the current configuration. Unlike the-loption, this list includes DSOs loaded viamod_so. httxt2dbm- A new program used to generate dbm files from text input,
for use in
RewriteMapwith thedbmmap type.
Module Developer Changes
- APR 1.0 API
- Apache 2.2 uses the APR 1.0 API. All deprecated functions and
symbols have been removed from
APRandAPR-Util. For details, see the . - Authn/Authz
- The bundled authentication and authorization modules have
been renamed along the following lines:
mod_auth_*-> Modules that implement an HTTP authentication mechanismmod_authn_*-> Modules that provide a backend authentication providermod_authz_*-> Modules that implement authorization (or access)mod_authnz_*-> Module that implements both authentication & authorization
- Connection Error Logging
- A new function,
ap_log_cerrorhas been added to log errors that occur with the client's connection. When logged, the message includes the client IP address. - Test Configuration Hook Added
- A new hook,
test_confighas been added to aid modules that want to execute special code only when the user passes-ttohttpd. - Set Threaded MPM's Stacksize
- A new directive,
ThreadStackSizehas 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. - Protocol handling for output filters
- 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
mod_filter, using theap_register_output_filter_protocolorap_filter_protocolcalls. - Monitor hook added
- Monitor hook enables modules to run regular/scheduled jobs in the parent (root) process.
- Regular expression API changes
- The
pcreposix.hheader is no longer available; it is replaced by the newap_regex.hheader. The POSIX.2regex.himplementation exposed by the old header is now available under theap_namespace fromap_regex.h. Calls toregcomp,regexecand so on can be replaced by calls toap_regcomp,ap_regexec. - DBD Framework (SQL Database API)
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.
Apache 2.1 and later provides the
ap_dbdAPI for managing database connections (including optimised strategies for threaded and unthreaded MPMs), while APR 1.2 and later provides theapr_dbdAPI for interacting with the database.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.