183N/A<!
DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" 268N/A <
title>Filters - Apache HTTPD</
title>
268N/A <!-- Background white, links blue (unvisited), navy (visited), red (active) --> 268N/A <
body bgcolor="#FFFFFF" text="#000000" link="#0000FF" 268N/A vlink="#000080" alink="#FF0000">
268N/A <
h1 align="CENTER">Filters</
h1>
268N/A <
td valign="top"><
strong>Related Modules</
strong><
br />
183N/A <
td valign="top"><
strong>Related Directives</
strong><
br />
183N/A <
p>A <
em>filter</
em> is a process that is applied to data that
183N/A is sent or received by the server. Data sent by clients to the
183N/A server is processed by <
em>input filters</
em> while data sent
183N/A by the server to the client is processed by <
em>output
183N/A filters</
em>. Multiple filters can be applied to the data, and
183N/A the order of the filters can be explicitly specified.</
p>
<
p>Filters are used internally by Apache to perform functions such
as chunking and byte-range request handling. In addition, modules
can provide filters that are selectable using run-time
configuration directives. The set of filters that apply to data
can be manipulated with the <
code>SetInputFilter</
code>,
<
code>SetOutputFilter</
code>, <
code>AddInputFilter</
code>, and
<
code>AddOutputFilter</
code> directives.</
p>
<
p>The following user-selectable filters are currently provided
with the Apache HTTP Server distribution.</
p>
<
dt>INCLUDES</
dt> <
dd>Server-Side Includes processing by <
a<
dt>DEFLATE</
dt> <
dd>Compress output before sending it to
<
p>In addition, the module <
a for external programs to be defined as filters.</
p>