mod_headers.html revision e0b181d3bfa99dfb992df3024b397660cb7afbe9
330c042543440d0987244c94c65d14eeb7af0868rbb<html xmlns="http://www.w3.org/TR/xhtml1/strict"><head><!--
faa6e5d8b210456ae4dad0398dfa40a19fd89d59coar XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
faa6e5d8b210456ae4dad0398dfa40a19fd89d59coar This file is generated from xml source: DO NOT EDIT
faa6e5d8b210456ae4dad0398dfa40a19fd89d59coar XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
faa6e5d8b210456ae4dad0398dfa40a19fd89d59coar --><title>mod_headers- Apache HTTP Server</title><link rel="stylesheet" type="text/css" href="/style/manual.css"/></head><body><blockquote><div align="center"><img src="/images/sub.gif" alt="[APACHE DOCUMENTATION]"/><h3>Apache HTTP Server Version 2.0</h3></div><h1 align="center">Apache Module mod_headers</h1><table bgcolor="#cccccc" cellpadding="0" cellspacing="1"><tr><td><table bgcolor="#ffffff"><tr><td valign="top"><span class="help">Description:</span></td><td>Customization of HTTP request
faa6e5d8b210456ae4dad0398dfa40a19fd89d59coar and response headers</td></tr><tr><td><a class="help" href="module-dict.html#Status">Status:</a></td><td>Extension</td></tr><tr><td><a class="help" href="module-dict.html#ModuleIdentifier">Module Identifier:</a></td><td>headers_module</td></tr><tr><td valign="top" align="left"><a class="help" href="module-dict.html#Compatibility">Compatibility:</a></td><td><compatibility>RequestHeader is available only in Apache 2.0</compatibility></td></tr></table></td></tr></table><h2>Summary</h2>
ed105ee460bbaf479f0aa0f59d3951da85066e27stoddard <p>This module provides directives to control and modify HTTP
ed105ee460bbaf479f0aa0f59d3951da85066e27stoddard request and response headers. Headers can be merged, replaced
ed105ee460bbaf479f0aa0f59d3951da85066e27stoddard or removed.</p>
ed105ee460bbaf479f0aa0f59d3951da85066e27stoddard<h2>Directives</h2><ul><li><a href="#header">Header</a></li><li><a href="#requestheader">RequestHeader</a></li></ul><h2>Order of Processing</h2>
ed105ee460bbaf479f0aa0f59d3951da85066e27stoddard <p>The directives provided by mod_header can occur almost
ed105ee460bbaf479f0aa0f59d3951da85066e27stoddard anywhere within the server configuration. They are valid in the
ed105ee460bbaf479f0aa0f59d3951da85066e27stoddard main server config and virtual host sections, inside
ed105ee460bbaf479f0aa0f59d3951da85066e27stoddard <Directory>, <Location> and <Files> sections,
21b8c3cb46cea2b31a585a95ce9f93f4f6abc35brbb and within .htaccess files.</p>
bae64a3e5bf7b96d8379e24f13273f26b3b29e16coar <p>The directives are processed in the following order:</p>
f1fa5e69040a3a72054d185f6087a7d1592b83e8rbb <p>Order is important. These two headers have a different
f1fa5e69040a3a72054d185f6087a7d1592b83e8rbb effect if reversed:</p>
f1fa5e69040a3a72054d185f6087a7d1592b83e8rbb<blockquote><table cellpadding="10"><tr><td bgcolor="#eeeeee"><code>
30e3e9b782c701f885583b7d13d8e46c37d7e1ddtrawickRequestHeader append MirrorID "mirror 12"<br/>
30e3e9b782c701f885583b7d13d8e46c37d7e1ddtrawick RequestHeader unset MirrorID
30e3e9b782c701f885583b7d13d8e46c37d7e1ddtrawick <p>This way round, the MirrorID header is not set. If reversed,
27faa3af8a50c1dc2dc6cb3049722378f85e5517rbb the MirrorID header is set to "mirror 12".</p>
141b1a93f508248cbc0e9a124cc38041eb3e2562rbb <li>Copy all request headers that begin with "TS" to the
141b1a93f508248cbc0e9a124cc38041eb3e2562rbb response headers:
141b1a93f508248cbc0e9a124cc38041eb3e2562rbb<blockquote><table cellpadding="10"><tr><td bgcolor="#eeeeee"><code>
141b1a93f508248cbc0e9a124cc38041eb3e2562rbb Header echo ^TS*
865980dc9aeb61741e586502440f0c0fea4835c6trawick <li>Add a header, MyHeader, to the response including a
865980dc9aeb61741e586502440f0c0fea4835c6trawick timestamp for when the request was received and how long it
865980dc9aeb61741e586502440f0c0fea4835c6trawick took to begin serving the request. This header can be used by
865980dc9aeb61741e586502440f0c0fea4835c6trawick the client to intuit load on the server or in isolating
865980dc9aeb61741e586502440f0c0fea4835c6trawick bottlenecks between the client and the server.
865980dc9aeb61741e586502440f0c0fea4835c6trawick<blockquote><table cellpadding="10"><tr><td bgcolor="#eeeeee"><code>
9a0d076511763b559a755133f6a182e6c24ef643rbb Header add MyHeader "%D %t"
9a0d076511763b559a755133f6a182e6c24ef643rbb results in this header being added to the response:
9a0d076511763b559a755133f6a182e6c24ef643rbb<blockquote><table cellpadding="10"><tr><td bgcolor="#eeeeee"><code>
9a0d076511763b559a755133f6a182e6c24ef643rbb MyHeader: D=3775428 t=991424704447256
b42a7e46e4f80282bd27e96d43c9510b14ccb9aarbb <li>Say hello to Joe
6501b757f710f75d47c950300d8110aca67dc0b0rbb<blockquote><table cellpadding="10"><tr><td bgcolor="#eeeeee"><code>
6501b757f710f75d47c950300d8110aca67dc0b0rbb Header add MyHeader "Hello Joe. It took %D microseconds for Apache to serve this request."
6501b757f710f75d47c950300d8110aca67dc0b0rbb results in this header being added to the response:
dfd4950edac888e671b96f62ff5382b7cb350d48rbb<blockquote><table cellpadding="10"><tr><td bgcolor="#eeeeee"><code>
dfd4950edac888e671b96f62ff5382b7cb350d48rbb MyHeader: Hello Joe. It took D=3775428 microseconds for Apache to serve this request.
a6d4b3f8d54aaf14d8ee5dda3a09bf8b6370dfa4wrowe <li>Conditionally send MyHeader on the response if and only
c9a95767fbf0f5fb0976a06b97a256033925e433rbb if header "MyRequestHeader" is present on the request. This
c9a95767fbf0f5fb0976a06b97a256033925e433rbb is useful for constructing headers in response to some client
c9a95767fbf0f5fb0976a06b97a256033925e433rbb stimulus. Note that this example requires the services of the
c9a95767fbf0f5fb0976a06b97a256033925e433rbb mod_setenvif module.
d8d839738b1e80b0f9c54e83677b3f2c46c22705rbb<blockquote><table cellpadding="10"><tr><td bgcolor="#eeeeee"><code>
d8d839738b1e80b0f9c54e83677b3f2c46c22705rbb SetEnvIf MyRequestHeader value HAVE_MyRequestHeader<br/>
d8d839738b1e80b0f9c54e83677b3f2c46c22705rbb Header add MyHeader "%D %t mytext" env=HAVE_MyRequestHeader
adaea88da2d103e4302e361c932b98cee86fb1c5rbb If the header "MyRequestHeader: value" is present on the
9635d7ffbd8ca441f85051f9a3adba17142d0b20rbb HTTP request, the response will contain the following
9635d7ffbd8ca441f85051f9a3adba17142d0b20rbb<blockquote><table cellpadding="10"><tr><td bgcolor="#eeeeee"><code>
9635d7ffbd8ca441f85051f9a3adba17142d0b20rbb MyHeader: D=3775428 t=991424704447256 mytext
0415e5e1b9b6eba6899a2e5ef18f8facb8db0cfbstoddard<hr/><h2><a name="Header">Header</a> <a name="header">Directive</a></h2><table bgcolor="#cccccc" border="0" cellspacing="0" cellpadding="1"><tr><td><table bgcolor="#ffffff"><tr><td><strong>Description: </strong></td><td>Configure HTTP response headers</td></tr><tr><td><a class="help" href="directive-dict.html#Syntax">Syntax:</a></td><td>Header set|append|add|unset|echo <em>header</em>
0415e5e1b9b6eba6899a2e5ef18f8facb8db0cfbstoddard[<em>value</em>]</td></tr><tr><td><a class="help" href="directive-dict.html#Context">Context:</a></td><td>server config, virtual host, directory, .htaccess</td></tr><tr><td><a class="help" href="directive-dict.html#Override">Override:</a></td><td>FileInfo</td></tr><tr><td><a class="help" href="directive-dict.html#Status">Status:</a></td><td>Extension</td></tr><tr><td><a class="help" href="directive-dict.html#Module">Module:</a></td><td>mod_headers</td></tr></table></td></tr></table>
0415e5e1b9b6eba6899a2e5ef18f8facb8db0cfbstoddard <p>This directive can replace, merge or remove HTTP response
1374444b4fab1475091e12a81663f379b73005efrbb headers. The header is modified just after the content handler
1374444b4fab1475091e12a81663f379b73005efrbb and output filters are run, allowing outgoing headers to be
1374444b4fab1475091e12a81663f379b73005efrbb modified. The action it performs is determined by the first
3233d057ad276d823bded5c24c3fd6729ed1a736rbb argument. This can be one of the following values:</p>
9927a2a72d50103f32323b53f5fc4577c1801327rbb The response header is set, replacing any previous header
9927a2a72d50103f32323b53f5fc4577c1801327rbb string.</li>
82d2eed8f2152aff3f7554951c133a9d404ebbc5rbb The response header is appended to any existing header of
82d2eed8f2152aff3f7554951c133a9d404ebbc5rbb the same name. When a new value is merged onto an existing
2e970b7ec485dde18f8fb3f494f98a3f68749859fanf header it is separated from the existing header with a comma.
2e970b7ec485dde18f8fb3f494f98a3f68749859fanf This is the HTTP standard way of giving a header multiple
2e970b7ec485dde18f8fb3f494f98a3f68749859fanf values.</li>
a5a7ecb732cfe89bb1f8e3c61b316c2075cefe52rbb The response header is added to the existing set of headers,
364701a102725758f2e3a511924381e2faa93e27rbb even if this header already exists. This can result in two
364701a102725758f2e3a511924381e2faa93e27rbb (or more) headers having the same name. This can lead to
364701a102725758f2e3a511924381e2faa93e27rbb unforeseen consequences, and in general "append" should be
364701a102725758f2e3a511924381e2faa93e27rbb used instead.</li>
0811e8a41d152f0016a385ce1dfa44f475425b70rbb The response header of this name is removed, if it exists.
0811e8a41d152f0016a385ce1dfa44f475425b70rbb If there are multiple headers of the same name, all will be
0811e8a41d152f0016a385ce1dfa44f475425b70rbb removed.</li>
957b9b3f5e47c6cc7c2d8d9e2224c7364e966c70rbb Request headers with this name are echoed back in the
957b9b3f5e47c6cc7c2d8d9e2224c7364e966c70rbb expression.</li>
e91c80d53d8ffa738283d923638fa3efd8aa6bf7rbb <p>This argument is followed by a <em>header</em> name, which
e91c80d53d8ffa738283d923638fa3efd8aa6bf7rbb can include the final colon, but it is not required. Case is
e91c80d53d8ffa738283d923638fa3efd8aa6bf7rbb ignored for set, append, add and unset. The <em>header</em>
9359bd100badb53fd8a465cb3a0a90b218b30c4cben name for echo is case sensitive and may be a regular
9359bd100badb53fd8a465cb3a0a90b218b30c4cben expression.</p>
d0211374a981173d4537e3f919c708b5f64040fcgstein <code>set</code> a <em>value</em> is specified as the third
d0211374a981173d4537e3f919c708b5f64040fcgstein argument. If <em>value</em> contains spaces, it should be
37d15e1062df9dcdd39ebee5bd2fdc75d4a6aa4arbb surrounded by doublequotes. <em>value</em> may be a character
37d15e1062df9dcdd39ebee5bd2fdc75d4a6aa4arbb string, a string containing format specifiers or a combination
37d15e1062df9dcdd39ebee5bd2fdc75d4a6aa4arbb of both. The following format specifiers are supported in
e3ec3193b69b45923c14915fa3ee3bc1f0215bafrbb<tr><td>%t: </td> <td>The time the request was received in Universal
e3ec3193b69b45923c14915fa3ee3bc1f0215bafrbbCoordinated Time since the epoch (Jan. 1, 1970) measured in
138c8f7cb8254e035c6f45288e3909cd9c21be5cmartin<tr><td>%D: </td> <td>The time from when the request was received to
138c8f7cb8254e035c6f45288e3909cd9c21be5cmartinthe time the headers are sent on the wire. This is a measure of the
138c8f7cb8254e035c6f45288e3909cd9c21be5cmartinduration of the request. The value is preceded by "D=".</td></tr>
adaea88da2d103e4302e361c932b98cee86fb1c5rbb<tr><td>%{FOOBAR}e:</td> <td>The contents of the <a href="/env.html">environment
8a76b3f3c93d39930182afa227d258218f80926brbb <p>When the <code class="directive">Header</code> directive is used with the
8e7c85d6eb9bf628f081763c5bd778b784d5001crbb <code>add</code>, <code>append</code>, or <code>set</code>
8e7c85d6eb9bf628f081763c5bd778b784d5001crbb argument, a fourth argument may be used to specify conditions
8e7c85d6eb9bf628f081763c5bd778b784d5001crbb under which the action will be taken. If the <a href="/env.html">environment variable</a> specified in the
8e7c85d6eb9bf628f081763c5bd778b784d5001crbb <code>env=...</code> argument exists (or if the environment
8e7c85d6eb9bf628f081763c5bd778b784d5001crbb variable does not exist and <code>env=!...</code> is specified)
97ad13ce0413b573e63512b57c874ebbd41065b2rbb then the action specified by the <code class="directive">Header</code> directive
97ad13ce0413b573e63512b57c874ebbd41065b2rbb will take effect. Otherwise, the directive will have no effect
2d3a1dd65798c72b7e46593614b4e27716cc5cderbb on the request.</p>
2d3a1dd65798c72b7e46593614b4e27716cc5cderbb <p>The Header directives are processed just before the response
2d3a1dd65798c72b7e46593614b4e27716cc5cderbb is sent to the network. These means that it is possible to set
78f2608a1583b3cb409e12be701392ad1a929653rbb and/or override most headers, except for those headers added by
78f2608a1583b3cb409e12be701392ad1a929653rbb the header filter.</p>
78f2608a1583b3cb409e12be701392ad1a929653rbb<hr/><h2><a name="RequestHeader">RequestHeader</a> <a name="requestheader">Directive</a></h2><table bgcolor="#cccccc" border="0" cellspacing="0" cellpadding="1"><tr><td><table bgcolor="#ffffff"><tr><td><strong>Description: </strong></td><td>Configure HTTP request headers</td></tr><tr><td><a class="help" href="directive-dict.html#Syntax">Syntax:</a></td><td>RequestHeader set|append|add|unset <em>header</em>
78f2608a1583b3cb409e12be701392ad1a929653rbb[<em>value</em>]</td></tr><tr><td><a class="help" href="directive-dict.html#Context">Context:</a></td><td>server config, virtual host, directory, .htaccess</td></tr><tr><td><a class="help" href="directive-dict.html#Override">Override:</a></td><td>FileInfo</td></tr><tr><td><a class="help" href="directive-dict.html#Status">Status:</a></td><td>Extension</td></tr><tr><td><a class="help" href="directive-dict.html#Module">Module:</a></td><td>mod_headers</td></tr></table></td></tr></table>
c5c3b5e33fca6425dc716e1dc51c10733d9b6bc3rbb <p>This directive can replace, merge or remove HTTP request
c5c3b5e33fca6425dc716e1dc51c10733d9b6bc3rbb headers. The header is modified just before the content handler
c5c3b5e33fca6425dc716e1dc51c10733d9b6bc3rbb is run, allowing incoming headers to be modified. The action it
c5c3b5e33fca6425dc716e1dc51c10733d9b6bc3rbb performs is determined by the first argument. This can be one
be7b08f10dc6b0be088c8b41009d89ea49ad4acarbb of the following values:</p>
2a0c3663b66c9af764267ac3c4e140e659598474ben The request header is set, replacing any previous header
2a0c3663b66c9af764267ac3c4e140e659598474ben with this name</li>
8a76b3f3c93d39930182afa227d258218f80926brbb The request header is appended to any existing header of the
8a76b3f3c93d39930182afa227d258218f80926brbb same name. When a new value is merged onto an existing header
8a76b3f3c93d39930182afa227d258218f80926brbb it is separated from the existing header with a comma. This
8a76b3f3c93d39930182afa227d258218f80926brbb is the HTTP standard way of giving a header multiple
11d400383ba9f941cc49e1a8da562fd172d3d7c5stoddard values.</li>
528e2a7d7cf6b8879291b59dd5afd8f6c7ae1b6brbb The request header is added to the existing set of headers,
528e2a7d7cf6b8879291b59dd5afd8f6c7ae1b6brbb even if this header already exists. This can result in two
528e2a7d7cf6b8879291b59dd5afd8f6c7ae1b6brbb (or more) headers having the same name. This can lead to
528e2a7d7cf6b8879291b59dd5afd8f6c7ae1b6brbb unforeseen consequences, and in general "append" should be
528e2a7d7cf6b8879291b59dd5afd8f6c7ae1b6brbb used instead.</li>
1a3161b56ebbbd036730d5372d4800cc495db212rbb The request header of this name is removed, if it exists. If
1a3161b56ebbbd036730d5372d4800cc495db212rbb there are multiple headers of the same name, all will be
1a3161b56ebbbd036730d5372d4800cc495db212rbb removed.</li>
2d87d8f191175a0683f430d790d81a5604b74ec6rbb <p>This argument is followed by a header name, which can
2d87d8f191175a0683f430d790d81a5604b74ec6rbb include the final colon, but it is not required. Case is
6bcee6b60a2fc4c96328af30e79bad4927ff30f3rbb <code>set</code> a value is given as the third argument. If
6bcee6b60a2fc4c96328af30e79bad4927ff30f3rbb this value contains spaces, it should be surrounded by double
6bcee6b60a2fc4c96328af30e79bad4927ff30f3rbb quotes. For unset, no value should be given.</p>
1e8d4cfede0bad3a1a33e3b2eef0ba6754746f72rbb <p>The <code class="directive">RequestHeader</code> directive is processed
1e8d4cfede0bad3a1a33e3b2eef0ba6754746f72rbb just before the request is run by its handler in the fixup phase.
1e8d4cfede0bad3a1a33e3b2eef0ba6754746f72rbb This should allow headers generated by the browser, or by Apache
1e8d4cfede0bad3a1a33e3b2eef0ba6754746f72rbb input filters to be overridden or modified.</p>
