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| author | Stefan Fritsch <sf@sfritsch.de> | 2011-12-27 19:42:03 +0100 |
|---|---|---|
| committer | Stefan Fritsch <sf@sfritsch.de> | 2011-12-27 19:42:03 +0100 |
| commit | 80db94fff6a9620fb469ee911347ed973e3f7735 (patch) | |
| tree | 35ccde4018b7e6b84103e5e85dc1085ef9e7d6c2 /docs/manual/mod/mod_headers.html.en | |
| download | apache2-upstream/2.2.3.tar.gz | |
Upstream tarball 2.2.3upstream/2.2.3
Diffstat (limited to 'docs/manual/mod/mod_headers.html.en')
| -rw-r--r-- | docs/manual/mod/mod_headers.html.en | 356 |
1 files changed, 356 insertions, 0 deletions
diff --git a/docs/manual/mod/mod_headers.html.en b/docs/manual/mod/mod_headers.html.en new file mode 100644 index 00000000..25c5bc06 --- /dev/null +++ b/docs/manual/mod/mod_headers.html.en @@ -0,0 +1,356 @@ +<?xml version="1.0" encoding="ISO-8859-1"?> +<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd"> +<html xmlns="http://www.w3.org/1999/xhtml" lang="en" xml:lang="en"><head><!-- + XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX + This file is generated from xml source: DO NOT EDIT + XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX + --> +<title>mod_headers - Apache HTTP Server</title> +<link href="../style/css/manual.css" rel="stylesheet" media="all" type="text/css" title="Main stylesheet" /> +<link href="../style/css/manual-loose-100pc.css" rel="alternate stylesheet" media="all" type="text/css" title="No Sidebar - Default font size" /> +<link href="../style/css/manual-print.css" rel="stylesheet" media="print" type="text/css" /> +<link href="../images/favicon.ico" rel="shortcut icon" /></head> +<body> +<div id="page-header"> +<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> +<p class="apache">Apache HTTP Server Version 2.2</p> +<img alt="" src="../images/feather.gif" /></div> +<div class="up"><a href="./"><img title="<-" alt="<-" src="../images/left.gif" /></a></div> +<div id="path"> +<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 2.2</a> > <a href="./">Modules</a></div> +<div id="page-content"> +<div id="preamble"><h1>Apache Module mod_headers</h1> +<div class="toplang"> +<p><span>Available Languages: </span><a href="../en/mod/mod_headers.html" title="English"> en </a> | +<a href="../ja/mod/mod_headers.html" hreflang="ja" rel="alternate" title="Japanese"> ja </a> | +<a href="../ko/mod/mod_headers.html" hreflang="ko" rel="alternate" title="Korean"> ko </a></p> +</div> +<table class="module"><tr><th><a href="module-dict.html#Description">Description:</a></th><td>Customization of HTTP request and response +headers</td></tr> +<tr><th><a href="module-dict.html#Status">Status:</a></th><td>Extension</td></tr> +<tr><th><a href="module-dict.html#ModuleIdentifier">Module Identifier:</a></th><td>headers_module</td></tr> +<tr><th><a href="module-dict.html#SourceFile">Source File:</a></th><td>mod_headers.c</td></tr> +<tr><th><a href="module-dict.html#Compatibility">Compatibility:</a></th><td><code class="directive"><a href="#requestheader">RequestHeader</a></code> +is available only in Apache 2.0</td></tr></table> +<h3>Summary</h3> + + <p>This module provides directives to control and modify HTTP + request and response headers. Headers can be merged, replaced + or removed.</p> +</div> +<div id="quickview"><h3 class="directives">Directives</h3> +<ul id="toc"> +<li><img alt="" src="../images/down.gif" /> <a href="#header">Header</a></li> +<li><img alt="" src="../images/down.gif" /> <a href="#requestheader">RequestHeader</a></li> +</ul> +<h3>Topics</h3> +<ul id="topics"> +<li><img alt="" src="../images/down.gif" /> <a href="#order">Order of Processing</a></li> +<li><img alt="" src="../images/down.gif" /> <a href="#early">Early and Late Processing</a></li> +<li><img alt="" src="../images/down.gif" /> <a href="#examples">Examples</a></li> +</ul></div> +<div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div> +<div class="section"> +<h2><a name="order" id="order">Order of Processing</a></h2> + + <p>The directives provided by <code class="module"><a href="../mod/mod_headers.html">mod_headers</a></code> can + occur almost anywhere within the server configuration, and can be + limited in scope by enclosing them in <a href="../sections.html">configuration sections</a>.</p> + + <p>Order of processing is important and is affected both by the + order in the configuration file and by placement in <a href="../sections.html#mergin">configuration sections</a>. These + two headers have a different effect if reversed:</p> + + <div class="example"><p><code> + RequestHeader append MirrorID "mirror 12"<br /> + RequestHeader unset MirrorID + </code></p></div> + + <p>This way round, the <code>MirrorID</code> header is not set. If + reversed, the MirrorID header is set to "mirror 12".</p> +</div><div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div> +<div class="section"> +<h2><a name="early" id="early">Early and Late Processing</a></h2> + <p><code class="module"><a href="../mod/mod_headers.html">mod_headers</a></code> can be applied either early or late + in the request. The normal mode is late, when Request Headers are + set immediately before running the content generator and Response + Headers just as the response is sent down the wire. Always use + Late mode in an operational server.</p> + + <p>Early mode is designed as a test/debugging aid for developers. + Directives defined using the <code>early</code> keyword are set + right at the beginning of processing the request. This means + they can be used to simulate different requests and set up test + cases, but it also means that headers may be changed at any time + by other modules before generating a Response.</p> + + <p>Because early directives are processed before the request path's + configuration is traversed, early headers can only be set in a + main server or virtual host context. Early directives cannot depend + on a request path, so they will fail in contexts such as + <code><Directory></code> or <code><Location></code>.</p> +</div><div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div> +<div class="section"> +<h2><a name="examples" id="examples">Examples</a></h2> + + <ol> + <li> + Copy all request headers that begin with "TS" to the + response headers: + + <div class="example"><p><code> + Header echo ^TS + </code></p></div> + </li> + + <li> + Add a header, <code>MyHeader</code>, to the response including a + timestamp for when the request was received and how long it + took to begin serving the request. This header can be used by + the client to intuit load on the server or in isolating + bottlenecks between the client and the server. + + <div class="example"><p><code> + Header add MyHeader "%D %t" + </code></p></div> + + <p>results in this header being added to the response:</p> + + <div class="example"><p><code> + MyHeader: D=3775428 t=991424704447256 + </code></p></div> + </li> + + <li> + Say hello to Joe + + <div class="example"><p><code> + Header add MyHeader "Hello Joe. It took %D microseconds \<br /> + for Apache to serve this request." + </code></p></div> + + <p>results in this header being added to the response:</p> + + <div class="example"><p><code> + MyHeader: Hello Joe. It took D=3775428 microseconds for Apache + to serve this request. + </code></p></div> + </li> + + <li> + Conditionally send <code>MyHeader</code> on the response if and + only if header "MyRequestHeader" is present on the request. This + is useful for constructing headers in response to some client + stimulus. Note that this example requires the services of the + <code class="module"><a href="../mod/mod_setenvif.html">mod_setenvif</a></code> module. + + <div class="example"><p><code> + SetEnvIf MyRequestHeader value HAVE_MyRequestHeader<br /> + Header add MyHeader "%D %t mytext" env=HAVE_MyRequestHeader<br /> + </code></p></div> + + <p>If the header <code>MyRequestHeader: value</code> is present on + the HTTP request, the response will contain the following header:</p> + + <div class="example"><p><code> + MyHeader: D=3775428 t=991424704447256 mytext + </code></p></div> + </li> + </ol> +</div> +<div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div> +<div class="directive-section"><h2><a name="Header" id="Header">Header</a> <a name="header" id="header">Directive</a></h2> +<table class="directive"> +<tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Configure HTTP response headers</td></tr> +<tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>Header [<var>condition</var>] set|append|add|unset|echo +<var>header</var> [<var>value</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 or remove HTTP response + headers. The header is modified just after the content handler + and output filters are run, allowing outgoing headers to be + modified.</p> + + <p>The optional <var>condition</var> can be either <code>onsuccess</code> + or <code>always</code>. It determines, which internal header table should be + operated on. <code>onsuccess</code> stands for <code>2<var>xx</var></code> + status codes and <code>always</code> for all status codes (including + <code>2<var>xx</var></code>). Especially if you want to unset headers + set by certain modules, you should try out, which table is affected.</p> + + <p>The action it performs is determined by the second + argument. This can be one of the following values:</p> + + <dl> + <dt><code>set</code></dt> + <dd>The response header is set, replacing any previous header + with this name. The <var>value</var> may be a format string.</dd> + + <dt><code>append</code></dt> + <dd>The response 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 response 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 "append" should be + used instead.</dd> + + <dt><code>unset</code></dt> + <dd>The response 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>echo</code></dt> + <dd>Request headers with this name are echoed back in the + response headers. <var>header</var> may be a + <a class="glossarylink" href="../glossary.html#regex" title="see glossary">regular expression</a>. + <var>value</var> must be omitted.</dd> + </dl> + + <p>This argument is followed by a <var>header</var> name, which + can include the final colon, but it is not required. Case is + ignored for <code>set</code>, <code>append</code>, <code>add</code> + and <code>unset</code>. The <var>header</var> name for <code>echo</code> + is case sensitive and may be a <a class="glossarylink" href="../glossary.html#regex" title="see glossary">regular + expression</a>.</p> + + <p>For <code>add</code>, <code>append</code> and <code>set</code> a + <var>value</var> is specified as the third argument. If <var>value</var> + contains spaces, it should be surrounded by doublequotes. + <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> +<tr><td><code>%%</code></td> + <td>The percent sign</td></tr> +<tr class="odd"><td><code>%t</code></td> + <td>The time the request was received in Universal Coordinated Time + since the epoch (Jan. 1, 1970) measured in microseconds. The value + is preceded by <code>t=</code>.</td></tr> +<tr><td><code>%D</code></td> + <td>The time from when the request was received to the time the + headers are sent on the wire. This is a measure of the duration + of the request. The value is preceded by <code>D=</code>.</td></tr> +<tr class="odd"><td><code>%{FOOBAR}e</code></td> + <td>The contents of the <a href="../env.html">environment + variable</a> <code>FOOBAR</code>.</td></tr> +<tr><td><code>%{FOOBAR}s</code></td> + <td>The contents of the <a href="mod_ssl.html#envvars">SSL environment + variable</a> <code>FOOBAR</code>, if <code class="module"><a href="../mod/mod_ssl.html">mod_ssl</a></code> is enabled.</td></tr> +</table> + + <div class="note"><h3>Note</h3> + <p>The <code>%s</code> format specifier is only available in + Apache 2.1 and later; it can be used instead of <code>%e</code> + to avoid the overhead of enabling <code>SSLOptions + +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> + + <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 <var>header</var> +[<var>value</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 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> + </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 + <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.</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> | +<a href="../ja/mod/mod_headers.html" hreflang="ja" rel="alternate" title="Japanese"> ja </a> | +<a href="../ko/mod/mod_headers.html" hreflang="ko" rel="alternate" title="Korean"> ko </a></p> +</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> +<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> +</body></html>
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