Apache HTTP Server Version 2.4
This document describes the use of filters in Apache.
Related Modules | Related Directives |
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The Filter Chain is available in Apache 2.0 and higher, and enables applications to process incoming and outgoing data in a highly flexible and configurable manner, regardless of where the data comes from. We can pre-process incoming data, and post-process outgoing data, at will. This is basically independent of the traditional request processing phases.
Some examples of filtering in the standard Apache distribution are:
mod_include
, implements server-side includes.mod_ssl
, implements SSL encryption (https).mod_deflate
, implements compression/decompression on the fly.mod_charset_lite
, transcodes between different character sets.mod_ext_filter
, runs an external program as a filter.Apache also uses a number of filters internally to perform functions like chunking and byte-range handling.
A wider range of applications are implemented by third-party filter modules. A few of these are:
mod_filter
, included in Apache 2.1 and later,
enables the filter chain to be configured dynamically at run time.
So for example you can set up a proxy to rewrite
HTML with an HTML filter and JPEG images with a completely
separate filter, despite the proxy having no pri