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381 lines
20 KiB
XML
<?xml version="1.0" encoding="ISO-8859-1"?>
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<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
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<html xmlns="http://www.w3.org/1999/xhtml" lang="en" xml:lang="en"><head><!--
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XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
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This file is generated from xml source: DO NOT EDIT
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XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
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-->
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<title>mod_headers - Apache HTTP Server</title>
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<link href="../style/css/manual.css" rel="stylesheet" media="all" type="text/css" title="Main stylesheet" />
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<link href="../style/css/manual-loose-100pc.css" rel="alternate stylesheet" media="all" type="text/css" title="No Sidebar - Default font size" />
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<link href="../style/css/manual-print.css" rel="stylesheet" media="print" type="text/css" />
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<link href="../images/favicon.ico" rel="shortcut icon" /></head>
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<body>
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||
<div id="page-header">
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<p class="menu"><a href="../mod/">Modules</a> | <a href="../mod/directives.html">Directives</a> | <a href="../faq/">FAQ</a> | <a href="../glossary.html">Glossary</a> | <a href="../sitemap.html">Sitemap</a></p>
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<p class="apache">Apache HTTP Server Version 2.3</p>
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<img alt="" src="../images/feather.gif" /></div>
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<div class="up"><a href="./"><img title="<-" alt="<-" src="../images/left.gif" /></a></div>
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<div id="path">
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<a href="http://www.apache.org/">Apache</a> > <a href="http://httpd.apache.org/">HTTP Server</a> > <a href="http://httpd.apache.org/docs/">Documentation</a> > <a href="../">Version 2.3</a> > <a href="./">Modules</a></div>
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<div id="page-content">
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<div id="preamble"><h1>Apache Module mod_headers</h1>
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<div class="toplang">
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<p><span>Available Languages: </span><a href="../en/mod/mod_headers.html" title="English"> en </a> |
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<a href="../ja/mod/mod_headers.html" hreflang="ja" rel="alternate" title="Japanese"> ja </a> |
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<a href="../ko/mod/mod_headers.html" hreflang="ko" rel="alternate" title="Korean"> ko </a></p>
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</div>
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<table class="module"><tr><th><a href="module-dict.html#Description">Description:</a></th><td>Customization of HTTP request and response
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headers</td></tr>
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<tr><th><a href="module-dict.html#Status">Status:</a></th><td>Extension</td></tr>
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<tr><th><a href="module-dict.html#ModuleIdentifier">Module<EFBFBD>Identifier:</a></th><td>headers_module</td></tr>
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<tr><th><a href="module-dict.html#SourceFile">Source<EFBFBD>File:</a></th><td>mod_headers.c</td></tr></table>
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<h3>Summary</h3>
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<p>This module provides directives to control and modify HTTP
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request and response headers. Headers can be merged, replaced
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or removed.</p>
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</div>
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<div id="quickview"><h3 class="directives">Directives</h3>
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<ul id="toc">
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<li><img alt="" src="../images/down.gif" /> <a href="#header">Header</a></li>
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<li><img alt="" src="../images/down.gif" /> <a href="#requestheader">RequestHeader</a></li>
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</ul>
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<h3>Topics</h3>
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<ul id="topics">
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<li><img alt="" src="../images/down.gif" /> <a href="#order">Order of Processing</a></li>
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<li><img alt="" src="../images/down.gif" /> <a href="#early">Early and Late Processing</a></li>
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<li><img alt="" src="../images/down.gif" /> <a href="#examples">Examples</a></li>
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</ul></div>
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<div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
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<div class="section">
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<h2><a name="order" id="order">Order of Processing</a></h2>
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<p>The directives provided by <code class="module"><a href="../mod/mod_headers.html">mod_headers</a></code> can
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occur almost anywhere within the server configuration, and can be
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limited in scope by enclosing them in <a href="../sections.html">configuration sections</a>.</p>
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<p>Order of processing is important and is affected both by the
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order in the configuration file and by placement in <a href="../sections.html#mergin">configuration sections</a>. These
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two headers have a different effect if reversed:</p>
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<div class="example"><p><code>
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RequestHeader append MirrorID "mirror 12"<br />
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RequestHeader unset MirrorID
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</code></p></div>
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<p>This way round, the <code>MirrorID</code> header is not set. If
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reversed, the MirrorID header is set to "mirror 12".</p>
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</div><div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
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<div class="section">
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<h2><a name="early" id="early">Early and Late Processing</a></h2>
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<p><code class="module"><a href="../mod/mod_headers.html">mod_headers</a></code> can be applied either early or late
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in the request. The normal mode is late, when Request Headers are
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set immediately before running the content generator and Response
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Headers just as the response is sent down the wire. Always use
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||
Late mode in an operational server.</p>
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||
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<p>Early mode is designed as a test/debugging aid for developers.
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Directives defined using the <code>early</code> keyword are set
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right at the beginning of processing the request. This means
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they can be used to simulate different requests and set up test
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||
cases, but it also means that headers may be changed at any time
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||
by other modules before generating a Response.</p>
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||
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<p>Because early directives are processed before the request path's
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||
configuration is traversed, early headers can only be set in a
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||
main server or virtual host context. Early directives cannot depend
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||
on a request path, so they will fail in contexts such as
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<code><Directory></code> or <code><Location></code>.</p>
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||
</div><div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
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<div class="section">
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<h2><a name="examples" id="examples">Examples</a></h2>
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<ol>
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<li>
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Copy all request headers that begin with "TS" to the
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response headers:
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<div class="example"><p><code>
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Header echo ^TS
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</code></p></div>
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</li>
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<li>
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Add a header, <code>MyHeader</code>, to the response including a
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timestamp for when the request was received and how long it
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took to begin serving the request. This header can be used by
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the client to intuit load on the server or in isolating
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bottlenecks between the client and the server.
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<div class="example"><p><code>
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Header add MyHeader "%D %t"
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</code></p></div>
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<p>results in this header being added to the response:</p>
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<div class="example"><p><code>
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MyHeader: D=3775428 t=991424704447256
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</code></p></div>
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</li>
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<li>
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Say hello to Joe
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<div class="example"><p><code>
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Header add MyHeader "Hello Joe. It took %D microseconds \<br />
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for Apache to serve this request."
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</code></p></div>
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<p>results in this header being added to the response:</p>
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<div class="example"><p><code>
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MyHeader: Hello Joe. It took D=3775428 microseconds for Apache
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to serve this request.
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</code></p></div>
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</li>
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<li>
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Conditionally send <code>MyHeader</code> on the response if and
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only if header "MyRequestHeader" is present on the request. This
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is useful for constructing headers in response to some client
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stimulus. Note that this example requires the services of the
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<code class="module"><a href="../mod/mod_setenvif.html">mod_setenvif</a></code> module.
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<div class="example"><p><code>
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SetEnvIf MyRequestHeader value HAVE_MyRequestHeader<br />
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Header add MyHeader "%D %t mytext" env=HAVE_MyRequestHeader<br />
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</code></p></div>
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<p>If the header <code>MyRequestHeader: value</code> is present on
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the HTTP request, the response will contain the following header:</p>
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<div class="example"><p><code>
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MyHeader: D=3775428 t=991424704447256 mytext
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</code></p></div>
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</li>
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<li>Enable DAV to work with Apache running HTTP through SSL hardware
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(<a href="http://svn.haxx.se/users/archive-2006-03/0549.shtml">problem description</a>) by replacing <var>https:</var> with
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<var>http:</var> in the <var>Destination</var> header:
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<div class="example"><p><code>
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RequestHeader edit Destination ^https: http: early
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</code></p></div>
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</li>
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</ol>
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</div>
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<div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
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<div class="directive-section"><h2><a name="Header" id="Header">Header</a> <a name="header" id="header">Directive</a></h2>
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||
<table class="directive">
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||
<tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Configure HTTP response headers</td></tr>
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||
<tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>Header [<var>condition</var>] set|append|add|unset|echo|edit
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<var>header</var> [<var>value</var>] [early|env=[!]<var>variable</var>]</code></td></tr>
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<tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
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||
<tr><th><a href="directive-dict.html#Override">Override:</a></th><td>FileInfo</td></tr>
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<tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr>
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<tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_headers</td></tr>
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||
</table>
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<p>This directive can replace, merge or remove HTTP response
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headers. The header is modified just after the content handler
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and output filters are run, allowing outgoing headers to be
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modified.</p>
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<p>The optional <var>condition</var> can be either <code>onsuccess</code>
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||
or <code>always</code>. It determines, which internal header table should be
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||
operated on. <code>onsuccess</code> stands for <code>2<var>xx</var></code>
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||
status codes and <code>always</code> for all status codes (including
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||
<code>2<var>xx</var></code>). Especially if you want to unset headers
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||
set by certain modules, you should try out, which table is affected.</p>
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||
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<p>The action it performs is determined by the second
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||
argument. This can be one of the following values:</p>
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<dl>
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||
<dt><code>set</code></dt>
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||
<dd>The response header is set, replacing any previous header
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with this name. The <var>value</var> may be a format string.</dd>
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||
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||
<dt><code>append</code></dt>
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||
<dd>The response header is appended to any existing header of
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||
the same name. When a new value is merged onto an existing
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||
header it is separated from the existing header with a comma.
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||
This is the HTTP standard way of giving a header multiple values.</dd>
|
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<dt><code>add</code></dt>
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||
<dd>The response header is added to the existing set of headers,
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||
even if this header already exists. This can result in two
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(or more) headers having the same name. This can lead to
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||
unforeseen consequences, and in general "append" should be
|
||
used instead.</dd>
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||
|
||
<dt><code>unset</code></dt>
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||
<dd>The response header of this name is removed, if it exists.
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||
If there are multiple headers of the same name, all will be
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||
removed. <var>value</var> must be omitted.</dd>
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<dt><code>echo</code></dt>
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||
<dd>Request headers with this name are echoed back in the
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response headers. <var>header</var> may be a
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<a class="glossarylink" href="../glossary.html#regex" title="see glossary">regular expression</a>.
|
||
<var>value</var> must be omitted.</dd>
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||
|
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<dt><code>edit</code></dt>
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||
<dd>If this request header exists, its value is transformed according
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||
to a <a class="glossarylink" href="../glossary.html#regex" title="see glossary">regular expression</a>
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search-and-replace. The <var>value</var> argument is a <a class="glossarylink" href="../glossary.html#regex" title="see glossary">regular expression</a>, and the <var>replacement</var>
|
||
is a replacement string, which may contain backreferences.</dd>
|
||
</dl>
|
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<p>This argument is followed by a <var>header</var> name, which
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||
can include the final colon, but it is not required. Case is
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ignored for <code>set</code>, <code>append</code>, <code>add</code>
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||
and <code>unset</code>. The <var>header</var> name for <code>echo</code>
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||
is case sensitive and may be a <a class="glossarylink" href="../glossary.html#regex" title="see glossary">regular
|
||
expression</a>.</p>
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||
|
||
<p>For <code>add</code>, <code>append</code> and <code>set</code> a
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||
<var>value</var> is specified as the third argument. If <var>value</var>
|
||
contains spaces, it should be surrounded by doublequotes.
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||
<var>value</var> may be a character string, a string containing format
|
||
specifiers or a combination of both. The following format specifiers
|
||
are supported in <var>value</var>:</p>
|
||
|
||
<table class="bordered"><tr class="header"><th>Format</th><th>Description</th></tr>
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||
<tr><td><code>%%</code></td>
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<td>The percent sign</td></tr>
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||
<tr class="odd"><td><code>%t</code></td>
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<td>The time the request was received in Universal Coordinated Time
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since the epoch (Jan. 1, 1970) measured in microseconds. The value
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is preceded by <code>t=</code>.</td></tr>
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<tr><td><code>%D</code></td>
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<td>The time from when the request was received to the time the
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headers are sent on the wire. This is a measure of the duration
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of the request. The value is preceded by <code>D=</code>.</td></tr>
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<tr class="odd"><td><code>%{FOOBAR}e</code></td>
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||
<td>The contents of the <a href="../env.html">environment
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||
variable</a> <code>FOOBAR</code>.</td></tr>
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||
<tr><td><code>%{FOOBAR}s</code></td>
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<td>The contents of the <a href="mod_ssl.html#envvars">SSL environment
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variable</a> <code>FOOBAR</code>, if <code class="module"><a href="../mod/mod_ssl.html">mod_ssl</a></code> is enabled.</td></tr>
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||
</table>
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<div class="note"><h3>Note</h3>
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<p>The <code>%s</code> format specifier is only available in
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Apache 2.1 and later; it can be used instead of <code>%e</code>
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||
to avoid the overhead of enabling <code>SSLOptions
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||
+StdEnvVars</code>. If <code>SSLOptions +StdEnvVars</code> must
|
||
be enabled anyway for some other reason, <code>%e</code> will be
|
||
more efficient than <code>%s</code>.</p>
|
||
</div>
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||
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||
<p>For <code>edit</code> there is both a <var>value</var> argument
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||
which is a <a class="glossarylink" href="../glossary.html#regex" title="see glossary">regular expression</a>,
|
||
and an additional <var>replacement</var> string.</p>
|
||
|
||
<p>The <code class="directive">Header</code> directive may be followed by an
|
||
an additional argument, which may be used to specify conditions under
|
||
which the action will be taken, or may be the keyword <code>early</code>
|
||
to specify <a href="#early">early processing</a>. If the
|
||
<a href="../env.html">environment variable</a> specified in the
|
||
<code>env=<var>...</var></code> argument exists (or if the environment
|
||
variable does not exist and <code>env=!<var>...</var></code> is specified)
|
||
then the action specified by the <code class="directive">Header</code> directive
|
||
will take effect. Otherwise, the directive will have no effect
|
||
on the request.</p>
|
||
|
||
<p>Except in <a href="#early">early</a> mode, the
|
||
<code class="directive">Header</code> directives are processed just
|
||
before the response is sent to the network. These means that it is
|
||
possible to set and/or override most headers, except for those headers
|
||
added by the header filter.</p>
|
||
|
||
</div>
|
||
<div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
|
||
<div class="directive-section"><h2><a name="RequestHeader" id="RequestHeader">RequestHeader</a> <a name="requestheader" id="requestheader">Directive</a></h2>
|
||
<table class="directive">
|
||
<tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Configure HTTP request headers</td></tr>
|
||
<tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>RequestHeader set|append|add|unset|edit <var>header</var>
|
||
[<var>value</var>] [<var>replacement</var>] [early|env=[!]<var>variable</var>]</code></td></tr>
|
||
<tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
|
||
<tr><th><a href="directive-dict.html#Override">Override:</a></th><td>FileInfo</td></tr>
|
||
<tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr>
|
||
<tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_headers</td></tr>
|
||
</table>
|
||
<p>This directive can replace, merge, change or remove HTTP request
|
||
headers. The header is modified just before the content handler
|
||
is run, allowing incoming headers to be modified. The action it
|
||
performs is determined by the first argument. This can be one
|
||
of the following values:</p>
|
||
|
||
<dl>
|
||
<dt><code>set</code></dt>
|
||
<dd>The request header is set, replacing any previous header
|
||
with this name</dd>
|
||
|
||
<dt><code>append</code></dt>
|
||
<dd>The request header is appended to any existing header of the
|
||
same name. When a new value is merged onto an existing header
|
||
it is separated from the existing header with a comma. This
|
||
is the HTTP standard way of giving a header multiple
|
||
values.</dd>
|
||
|
||
<dt><code>add</code></dt>
|
||
<dd>The request header is added to the existing set of headers,
|
||
even if this header already exists. This can result in two
|
||
(or more) headers having the same name. This can lead to
|
||
unforeseen consequences, and in general <code>append</code> should be
|
||
used instead.</dd>
|
||
|
||
<dt><code>unset</code></dt>
|
||
<dd>The request header of this name is removed, if it exists. If
|
||
there are multiple headers of the same name, all will be removed.
|
||
<var>value</var> must be omitted.</dd>
|
||
|
||
<dt><code>edit</code></dt>
|
||
<dd>If this request header exists, its value is transformed according
|
||
to a <a class="glossarylink" href="../glossary.html#regex" title="see glossary">regular expression</a>
|
||
search-and-replace. The <var>value</var> argument is a <a class="glossarylink" href="../glossary.html#regex" title="see glossary">regular expression</a>, and the <var>replacement</var>
|
||
is a replacement string, which may contain backreferences.</dd>
|
||
</dl>
|
||
|
||
<p>This argument is followed by a header name, which can
|
||
include the final colon, but it is not required. Case is
|
||
ignored. For <code>add</code>, <code>append</code> and
|
||
<code>set</code> a <var>value</var> is given as the third argument. If a
|
||
<var>value</var> contains spaces, it should be surrounded by double
|
||
quotes. For unset, no <var>value</var> should be given.
|
||
<var>value</var> may be a character string, a string containing format
|
||
specifiers or a combination of both. The supported format specifiers
|
||
are the same as for the <code class="directive"><a href="#header">Header</a></code>,
|
||
please have a look there for details. For <code>edit</code> both
|
||
a <var>value</var> and a <var>replacement</var> are required, and are
|
||
a <a class="glossarylink" href="../glossary.html#regex" title="see glossary">regular expression</a> and a
|
||
replacement string respectively.</p>
|
||
|
||
<p>The <code class="directive">RequestHeader</code> directive may be followed by
|
||
an additional argument, which may be used to specify conditions under
|
||
which the action will be taken, or may be the keyword <code>early</code>
|
||
to specify <a href="#early">early processing</a>. If the
|
||
<a href="../env.html">environment
|
||
variable</a> specified in the <code>env=<var>...</var></code> argument
|
||
exists (or if the environment variable does not exist and
|
||
<code>env=!<var>...</var></code> is specified) then the action specified
|
||
by the <code class="directive">RequestHeader</code> directive will take effect.
|
||
Otherwise, the directive will have no effect on the request.</p>
|
||
|
||
<p>Except in <a href="#early">early</a> mode, the
|
||
<code class="directive">RequestHeader</code> directive is processed
|
||
just before the request is run by its handler in the fixup phase.
|
||
This should allow headers generated by the browser, or by Apache
|
||
input filters to be overridden or modified.</p>
|
||
|
||
</div>
|
||
</div>
|
||
<div class="bottomlang">
|
||
<p><span>Available Languages: </span><a href="../en/mod/mod_headers.html" title="English"> en </a> |
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<a href="../ja/mod/mod_headers.html" hreflang="ja" rel="alternate" title="Japanese"> ja </a> |
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<a href="../ko/mod/mod_headers.html" hreflang="ko" rel="alternate" title="Korean"> ko </a></p>
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</div><div id="footer">
|
||
<p class="apache">Copyright 2006 The Apache Software Foundation.<br />Licensed under the <a href="http://www.apache.org/licenses/LICENSE-2.0">Apache License, Version 2.0</a>.</p>
|
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<p class="menu"><a href="../mod/">Modules</a> | <a href="../mod/directives.html">Directives</a> | <a href="../faq/">FAQ</a> | <a href="../glossary.html">Glossary</a> | <a href="../sitemap.html">Sitemap</a></p></div>
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