1
<?xml version="1.0" encoding="ISO-8859-1"?>
2
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
3
<html xmlns="http://www.w3.org/1999/xhtml" lang="en" xml:lang="en"><head><!--
4
XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
5
This file is generated from xml source: DO NOT EDIT
6
XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
8
<title>mod_headers - Apache HTTP Server</title>
9
<link href="../style/css/manual.css" rel="stylesheet" media="all" type="text/css" title="Main stylesheet" />
10
<link href="../style/css/manual-loose-100pc.css" rel="alternate stylesheet" media="all" type="text/css" title="No Sidebar - Default font size" />
11
<link href="../style/css/manual-print.css" rel="stylesheet" media="print" type="text/css" />
12
<link href="../images/favicon.ico" rel="shortcut icon" /></head>
14
<div id="page-header">
15
<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>
16
<p class="apache">Apache HTTP Server Version 2.2</p>
17
<img alt="" src="../images/feather.gif" /></div>
18
<div class="up"><a href="./"><img title="<-" alt="<-" src="../images/left.gif" /></a></div>
20
<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>
21
<div id="page-content">
22
<div id="preamble"><h1>Apache Module mod_headers</h1>
24
<p><span>Available Languages: </span><a href="../en/mod/mod_headers.html" title="English"> en </a> |
25
<a href="../ja/mod/mod_headers.html" hreflang="ja" rel="alternate" title="Japanese"> ja </a> |
26
<a href="../ko/mod/mod_headers.html" hreflang="ko" rel="alternate" title="Korean"> ko </a></p>
28
<table class="module"><tr><th><a href="module-dict.html#Description">Description:</a></th><td>Customization of HTTP request and response
30
<tr><th><a href="module-dict.html#Status">Status:</a></th><td>Extension</td></tr>
31
<tr><th><a href="module-dict.html#ModuleIdentifier">Module�Identifier:</a></th><td>headers_module</td></tr>
32
<tr><th><a href="module-dict.html#SourceFile">Source�File:</a></th><td>mod_headers.c</td></tr>
33
<tr><th><a href="module-dict.html#Compatibility">Compatibility:</a></th><td><code class="directive"><a href="#requestheader">RequestHeader</a></code>
34
is available only in Apache 2.0</td></tr></table>
37
<p>This module provides directives to control and modify HTTP
38
request and response headers. Headers can be merged, replaced
41
<div id="quickview"><h3 class="directives">Directives</h3>
43
<li><img alt="" src="../images/down.gif" /> <a href="#header">Header</a></li>
44
<li><img alt="" src="../images/down.gif" /> <a href="#requestheader">RequestHeader</a></li>
48
<li><img alt="" src="../images/down.gif" /> <a href="#order">Order of Processing</a></li>
49
<li><img alt="" src="../images/down.gif" /> <a href="#early">Early and Late Processing</a></li>
50
<li><img alt="" src="../images/down.gif" /> <a href="#examples">Examples</a></li>
52
<div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
54
<h2><a name="order" id="order">Order of Processing</a></h2>
56
<p>The directives provided by <code class="module"><a href="../mod/mod_headers.html">mod_headers</a></code> can
57
occur almost anywhere within the server configuration, and can be
58
limited in scope by enclosing them in <a href="../sections.html">configuration sections</a>.</p>
60
<p>Order of processing is important and is affected both by the
61
order in the configuration file and by placement in <a href="../sections.html#mergin">configuration sections</a>. These
62
two headers have a different effect if reversed:</p>
64
<div class="example"><p><code>
65
RequestHeader append MirrorID "mirror 12"<br />
66
RequestHeader unset MirrorID
69
<p>This way round, the <code>MirrorID</code> header is not set. If
70
reversed, the MirrorID header is set to "mirror 12".</p>
71
</div><div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
73
<h2><a name="early" id="early">Early and Late Processing</a></h2>
74
<p><code class="module"><a href="../mod/mod_headers.html">mod_headers</a></code> can be applied either early or late
75
in the request. The normal mode is late, when Request Headers are
76
set immediately before running the content generator and Response
77
Headers just as the response is sent down the wire. Always use
78
Late mode in an operational server.</p>
80
<p>Early mode is designed as a test/debugging aid for developers.
81
Directives defined using the <code>early</code> keyword are set
82
right at the beginning of processing the request. This means
83
they can be used to simulate different requests and set up test
84
cases, but it also means that headers may be changed at any time
85
by other modules before generating a Response.</p>
87
<p>Because early directives are processed before the request path's
88
configuration is traversed, early headers can only be set in a
89
main server or virtual host context. Early directives cannot depend
90
on a request path, so they will fail in contexts such as
91
<code><Directory></code> or <code><Location></code>.</p>
92
</div><div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
94
<h2><a name="examples" id="examples">Examples</a></h2>
98
Copy all request headers that begin with "TS" to the
101
<div class="example"><p><code>
107
Add a header, <code>MyHeader</code>, to the response including a
108
timestamp for when the request was received and how long it
109
took to begin serving the request. This header can be used by
110
the client to intuit load on the server or in isolating
111
bottlenecks between the client and the server.
113
<div class="example"><p><code>
114
Header add MyHeader "%D %t"
117
<p>results in this header being added to the response:</p>
119
<div class="example"><p><code>
120
MyHeader: D=3775428 t=991424704447256
127
<div class="example"><p><code>
128
Header add MyHeader "Hello Joe. It took %D microseconds \<br />
129
for Apache to serve this request."
132
<p>results in this header being added to the response:</p>
134
<div class="example"><p><code>
135
MyHeader: Hello Joe. It took D=3775428 microseconds for Apache
136
to serve this request.
141
Conditionally send <code>MyHeader</code> on the response if and
142
only if header "MyRequestHeader" is present on the request. This
143
is useful for constructing headers in response to some client
144
stimulus. Note that this example requires the services of the
145
<code class="module"><a href="../mod/mod_setenvif.html">mod_setenvif</a></code> module.
147
<div class="example"><p><code>
148
SetEnvIf MyRequestHeader value HAVE_MyRequestHeader<br />
149
Header add MyHeader "%D %t mytext" env=HAVE_MyRequestHeader<br />
152
<p>If the header <code>MyRequestHeader: value</code> is present on
153
the HTTP request, the response will contain the following header:</p>
155
<div class="example"><p><code>
156
MyHeader: D=3775428 t=991424704447256 mytext
161
<div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
162
<div class="directive-section"><h2><a name="Header" id="Header">Header</a> <a name="header" id="header">Directive</a></h2>
163
<table class="directive">
164
<tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Configure HTTP response headers</td></tr>
165
<tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>Header [<var>condition</var>] set|append|add|unset|echo
166
<var>header</var> [<var>value</var>] [early|env=[!]<var>variable</var>]</code></td></tr>
167
<tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
168
<tr><th><a href="directive-dict.html#Override">Override:</a></th><td>FileInfo</td></tr>
169
<tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr>
170
<tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_headers</td></tr>
172
<p>This directive can replace, merge or remove HTTP response
173
headers. The header is modified just after the content handler
174
and output filters are run, allowing outgoing headers to be
177
<p>The optional <var>condition</var> can be either <code>onsuccess</code>
178
or <code>always</code>. It determines, which internal header table should be
179
operated on. <code>onsuccess</code> stands for <code>2<var>xx</var></code>
180
status codes and <code>always</code> for all status codes (including
181
<code>2<var>xx</var></code>). Especially if you want to unset headers
182
set by certain modules, you should try out, which table is affected.</p>
184
<p>The action it performs is determined by the second
185
argument. This can be one of the following values:</p>
188
<dt><code>set</code></dt>
189
<dd>The response header is set, replacing any previous header
190
with this name. The <var>value</var> may be a format string.</dd>
192
<dt><code>append</code></dt>
193
<dd>The response header is appended to any existing header of
194
the same name. When a new value is merged onto an existing
195
header it is separated from the existing header with a comma.
196
This is the HTTP standard way of giving a header multiple values.</dd>
198
<dt><code>add</code></dt>
199
<dd>The response header is added to the existing set of headers,
200
even if this header already exists. This can result in two
201
(or more) headers having the same name. This can lead to
202
unforeseen consequences, and in general "append" should be
205
<dt><code>unset</code></dt>
206
<dd>The response header of this name is removed, if it exists.
207
If there are multiple headers of the same name, all will be
208
removed. <var>value</var> must be omitted.</dd>
210
<dt><code>echo</code></dt>
211
<dd>Request headers with this name are echoed back in the
212
response headers. <var>header</var> may be a
213
<a class="glossarylink" href="../glossary.html#regex" title="see glossary">regular expression</a>.
214
<var>value</var> must be omitted.</dd>
217
<p>This argument is followed by a <var>header</var> name, which
218
can include the final colon, but it is not required. Case is
219
ignored for <code>set</code>, <code>append</code>, <code>add</code>
220
and <code>unset</code>. The <var>header</var> name for <code>echo</code>
221
is case sensitive and may be a <a class="glossarylink" href="../glossary.html#regex" title="see glossary">regular
224
<p>For <code>add</code>, <code>append</code> and <code>set</code> a
225
<var>value</var> is specified as the third argument. If <var>value</var>
226
contains spaces, it should be surrounded by doublequotes.
227
<var>value</var> may be a character string, a string containing format
228
specifiers or a combination of both. The following format specifiers
229
are supported in <var>value</var>:</p>
231
<table class="bordered"><tr class="header"><th>Format</th><th>Description</th></tr>
232
<tr><td><code>%%</code></td>
233
<td>The percent sign</td></tr>
234
<tr class="odd"><td><code>%t</code></td>
235
<td>The time the request was received in Universal Coordinated Time
236
since the epoch (Jan. 1, 1970) measured in microseconds. The value
237
is preceded by <code>t=</code>.</td></tr>
238
<tr><td><code>%D</code></td>
239
<td>The time from when the request was received to the time the
240
headers are sent on the wire. This is a measure of the duration
241
of the request. The value is preceded by <code>D=</code>.</td></tr>
242
<tr class="odd"><td><code>%{FOOBAR}e</code></td>
243
<td>The contents of the <a href="../env.html">environment
244
variable</a> <code>FOOBAR</code>.</td></tr>
245
<tr><td><code>%{FOOBAR}s</code></td>
246
<td>The contents of the <a href="mod_ssl.html#envvars">SSL environment
247
variable</a> <code>FOOBAR</code>, if <code class="module"><a href="../mod/mod_ssl.html">mod_ssl</a></code> is enabled.</td></tr>
250
<div class="note"><h3>Note</h3>
251
<p>The <code>%s</code> format specifier is only available in
252
Apache 2.1 and later; it can be used instead of <code>%e</code>
253
to avoid the overhead of enabling <code>SSLOptions
254
+StdEnvVars</code>. If <code>SSLOptions +StdEnvVars</code> must
255
be enabled anyway for some other reason, <code>%e</code> will be
256
more efficient than <code>%s</code>.</p>
259
<p>The <code class="directive">Header</code> directive may be followed by an
260
an additional argument, which may be used to specify conditions under
261
which the action will be taken, or may be the keyword <code>early</code>
262
to specify <a href="#early">early processing</a>. If the
263
<a href="../env.html">environment variable</a> specified in the
264
<code>env=<var>...</var></code> argument exists (or if the environment
265
variable does not exist and <code>env=!<var>...</var></code> is specified)
266
then the action specified by the <code class="directive">Header</code> directive
267
will take effect. Otherwise, the directive will have no effect
270
<p>Except in <a href="#early">early</a> mode, the
271
<code class="directive">Header</code> directives are processed just
272
before the response is sent to the network. These means that it is
273
possible to set and/or override most headers, except for those headers
274
added by the header filter.</p>
277
<div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
278
<div class="directive-section"><h2><a name="RequestHeader" id="RequestHeader">RequestHeader</a> <a name="requestheader" id="requestheader">Directive</a></h2>
279
<table class="directive">
280
<tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Configure HTTP request headers</td></tr>
281
<tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>RequestHeader set|append|add|unset <var>header</var>
282
[<var>value</var>] [early|env=[!]<var>variable</var>]</code></td></tr>
283
<tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
284
<tr><th><a href="directive-dict.html#Override">Override:</a></th><td>FileInfo</td></tr>
285
<tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr>
286
<tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_headers</td></tr>
288
<p>This directive can replace, merge or remove HTTP request
289
headers. The header is modified just before the content handler
290
is run, allowing incoming headers to be modified. The action it
291
performs is determined by the first argument. This can be one
292
of the following values:</p>
295
<dt><code>set</code></dt>
296
<dd>The request header is set, replacing any previous header
299
<dt><code>append</code></dt>
300
<dd>The request header is appended to any existing header of the
301
same name. When a new value is merged onto an existing header
302
it is separated from the existing header with a comma. This
303
is the HTTP standard way of giving a header multiple
306
<dt><code>add</code></dt>
307
<dd>The request header is added to the existing set of headers,
308
even if this header already exists. This can result in two
309
(or more) headers having the same name. This can lead to
310
unforeseen consequences, and in general <code>append</code> should be
313
<dt><code>unset</code></dt>
314
<dd>The request header of this name is removed, if it exists. If
315
there are multiple headers of the same name, all will be removed.
316
<var>value</var> must be omitted.</dd>
319
<p>This argument is followed by a header name, which can
320
include the final colon, but it is not required. Case is
321
ignored. For <code>add</code>, <code>append</code> and
322
<code>set</code> a <var>value</var> is given as the third argument. If
323
<var>value</var> contains spaces, it should be surrounded by double
324
quotes. For unset, no <var>value</var> should be given.
325
<var>value</var> may be a character string, a string containing format
326
specifiers or a combination of both. The supported format specifiers
327
are the same as for the <code class="directive"><a href="#header">Header</a></code>,
328
please have a look there for details.</p>
330
<p>The <code class="directive">RequestHeader</code> directive may be followed by
331
an additional argument, which may be used to specify conditions under
332
which the action will be taken, or may be the keyword <code>early</code>
333
to specify <a href="#early">early processing</a>. If the
334
<a href="../env.html">environment
335
variable</a> specified in the <code>env=<var>...</var></code> argument
336
exists (or if the environment variable does not exist and
337
<code>env=!<var>...</var></code> is specified) then the action specified
338
by the <code class="directive">RequestHeader</code> directive will take effect.
339
Otherwise, the directive will have no effect on the request.</p>
341
<p>Except in <a href="#early">early</a> mode, the
342
<code class="directive">RequestHeader</code> directive is processed
343
just before the request is run by its handler in the fixup phase.
344
This should allow headers generated by the browser, or by Apache
345
input filters to be overridden or modified.</p>
349
<div class="bottomlang">
350
<p><span>Available Languages: </span><a href="../en/mod/mod_headers.html" title="English"> en </a> |
351
<a href="../ja/mod/mod_headers.html" hreflang="ja" rel="alternate" title="Japanese"> ja </a> |
352
<a href="../ko/mod/mod_headers.html" hreflang="ko" rel="alternate" title="Korean"> ko </a></p>
353
</div><div id="footer">
354
<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>
355
<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>
b'\\ No newline at end of file'
added
removed
docs/manual/mod/mod_headers.html.en
