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<title>mod_setenvif - Apache HTTP Server</title>
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<div id="preamble"><h1>Apache Module mod_setenvif</h1>
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<table class="module"><tr><th><a href="module-dict.html#Description">Description:</a></th><td>Allows the setting of environment variables based
on characteristics of the request</td></tr>
<tr><th><a href="module-dict.html#ModuleIdentifier">Module�Identifier:</a></th><td>setenvif_module</td></tr>
<tr><th><a href="module-dict.html#SourceFile">Source�File:</a></th><td>mod_setenvif.c</td></tr></table>
<h3>Summary</h3>
<p>The <code class="module"><a href="/mod/mod_setenvif.html">mod_setenvif</a></code> module allows you to set
internal environment variables according to whether different aspects of
the request match regular expressions you specify. These
environment variables can be used by other parts of the server
to make decisions about actions to be taken, as well as becoming
available to CGI scripts and SSI pages.</p>
<p>The directives are considered in the order they appear in
the configuration files. So more complex sequences can be used,
such as this example, which sets <code>netscape</code> if the
browser is mozilla but not MSIE.</p>
<div class="example"><p><code>
BrowserMatch ^Mozilla netscape<br />
BrowserMatch MSIE !netscape<br />
</code></p></div>
</div>
<div id="quickview"><h3 class="directives">Directives</h3>
<ul id="toc">
</ul>
<h3>See also</h3>
<ul class="seealso">
</ul></div>
<div class="directive-section"><h2><a name="BrowserMatch" id="BrowserMatch">BrowserMatch</a> <a name="browsermatch" id="browsermatch">Directive</a></h2>
<table class="directive">
<tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Sets environment variables conditional on HTTP User-Agent
</td></tr>
<tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>BrowserMatch <em>regex [!]env-variable</em>[=<em>value</em>]
[[!]<em>env-variable</em>[=<em>value</em>]] ...</code></td></tr>
<tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
</table>
<p>The <code class="directive">BrowserMatch</code> is a special cases of the
<code class="directive"><a href="#setenvif">SetEnvIf</a></code> directive that
sets environment variables conditional on the
<code>User-Agent</code> HTTP request header. The following two
lines have the same effect:</p>
<div class="example"><p><code>
BrowserMatchNoCase Robot is_a_robot<br />
SetEnvIfNoCase User-Agent Robot is_a_robot<br />
</code></p></div>
<p>Some additional examples:</p>
<div class="example"><p><code>
BrowserMatch ^Mozilla forms jpeg=yes browser=netscape<br />
BrowserMatch "^Mozilla/[2-3]" tables agif frames javascript<br />
BrowserMatch MSIE !javascript<br />
</code></p></div>
</div>
<div class="directive-section"><h2><a name="BrowserMatchNoCase" id="BrowserMatchNoCase">BrowserMatchNoCase</a> <a name="browsermatchnocase" id="browsermatchnocase">Directive</a></h2>
<table class="directive">
<tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Sets environment variables conditional on User-Agent without
respect to case</td></tr>
<tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>BrowserMatchNoCase <em>regex [!]env-variable</em>[=<em>value</em>]
[[!]<em>env-variable</em>[=<em>value</em>]] ...</code></td></tr>
<tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
</table>
<p>The <code class="directive">BrowserMatchNoCase</code> directive is
semantically identical to the <code class="directive"><a href="#browsermatch">BrowserMatch</a></code> directive.
However, it provides for case-insensitive matching. For
example:</p>
<div class="example"><p><code>
BrowserMatchNoCase mac platform=macintosh<br />
BrowserMatchNoCase win platform=windows<br />
</code></p></div>
<p>The <code class="directive">BrowserMatch</code> and
<code class="directive">BrowserMatchNoCase</code> directives are special cases of
the <code class="directive"><a href="#setenvif">SetEnvIf</a></code> and <code class="directive"><a href="#setenvifnocase">SetEnvIfNoCase</a></code>
directives. The following two lines have the same effect:</p>
<div class="example"><p><code>
BrowserMatchNoCase Robot is_a_robot<br />
SetEnvIfNoCase User-Agent Robot is_a_robot<br />
</code></p></div>
</div>
<div class="directive-section"><h2><a name="SetEnvIf" id="SetEnvIf">SetEnvIf</a> <a name="setenvif" id="setenvif">Directive</a></h2>
<table class="directive">
<tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Sets environment variables based on attributes of the request
</td></tr>
regex [!]env-variable</em>[=<em>value</em>]
[[!]<em>env-variable</em>[=<em>value</em>]] ...</code></td></tr>
<tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
</table>
<p>The <code class="directive">SetEnvIf</code> directive defines
environment variables based on attributes of the request. The
<em>attribute</em> specified in the first argument can be one of four
things:</p>
<ol>
<li>An HTTP request header field (see <a href="http://www.rfc-editor.org/rfc/rfc2616.txt">RFC2616</a>
for more information about these); for example: <code>Host</code>,
<code>User-Agent</code>, <code>Referer</code>, and
<code>Accept-Language</code>. A regular expression may be
used to specify a set of request headers.</li>
<li>One of the following aspects of the request:
<ul>
<li><code>Remote_Host</code> - the hostname (if available) of
the client making the request</li>
<li><code>Remote_Addr</code> - the IP address of the client
making the request</li>
<li><code>Server_Addr</code> - the IP address of the server
on which the request was received (only with versions later
than 2.0.43)</li>
<li><code>Request_Method</code> - the name of the method
being used (<code>GET</code>, <code>POST</code>, <em>et
cetera</em>)</li>
<li><code>Request_Protocol</code> - the name and version of
<li><code>Request_URI</code> - the resource requested on the HTTP
request line -- generally the portion of the URL
following the scheme and host portion without the query string. See
directive of <code class="module"><a href="/mod/mod_rewrite.html">mod_rewrite</a></code> for extra information on
how to match your query string.</li>
</ul>
</li>
<li>The name of an environment variable in the list of those
associated with the request. This allows
<code class="directive">SetEnvIf</code> directives to test against the result
of prior matches. Only those environment variables defined by earlier
<code>SetEnvIf[NoCase]</code> directives are available for testing in
this manner. 'Earlier' means that they were defined at a broader scope
(such as server-wide) or previously in the current directive's scope.
Environment variables will be considered only if there was no match
among request characteristics and a regular expression was not
used for the <em>attribute</em>.</li>
</ol>
<p>The second argument (<em>regex</em>) is a <a class="glossarylink" href="/glossary.html#regex" title="see glossary">regular expression</a>. If the <em>regex</em>
matches against the <em>attribute</em>, then the remainder of the
arguments are evaluated.</p>
<p>The rest of the arguments give the names of variables to set, and
optionally values to which they should be set. These take the form
of</p>
<ol>
<li><code><em>varname</em></code>, or</li>
<li><code>!<em>varname</em></code>, or</li>
<li><code><em>varname</em>=<em>value</em></code></li>
</ol>
<p>In the first form, the value will be set to "1". The second
will remove the given variable if already defined, and the
third will set the variable to the literal value given by
<code><em>value</em></code>. Since version 2.0.51, Apache httpd will
recognize occurrences of <code>$1</code>..<code>$9</code> within
<var>value</var> and replace them by parenthesized subexpressions
of <var>regex</var>.</p>
<div class="example"><h3>Example:</h3><p><code>
SetEnvIf Request_URI "\.gif$" object_is_image=gif<br />
SetEnvIf Request_URI "\.jpg$" object_is_image=jpg<br />
SetEnvIf Request_URI "\.xbm$" object_is_image=xbm<br />
:<br />
SetEnvIf Referer www\.mydomain\.example\.com intra_site_referral<br />
:<br />
SetEnvIf object_is_image xbm XBIT_PROCESSING=1<br />
:<br />
SetEnvIf ^TS ^[a-z] HAVE_TS<br />
</code></p></div>
<p>The first three will set the environment variable
<code>object_is_image</code> if the request was for an image
file, and the fourth sets <code>intra_site_referral</code> if
the referring page was somewhere on the
<p>The last example will set environment variable
<code>HAVE_TS</code> if the request contains any headers that
begin with "TS" whose values begins with any character in the
set [a-z].</p>
<h3>See also</h3>
<ul>
for additional examples.
</li>
</ul>
</div>
<div class="directive-section"><h2><a name="SetEnvIfExpr" id="SetEnvIfExpr">SetEnvIfExpr</a> <a name="setenvifexpr" id="setenvifexpr">Directive</a></h2>
<table class="directive">
<tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Sets environment variables based on an ap_expr expression</td></tr>
[!]env-variable</em>[=<em>value</em>]
[[!]<em>env-variable</em>[=<em>value</em>]] ...</code></td></tr>
<tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
</table>
<p>The <code class="directive">SetEnvIfExpr</code> directive defines
environment variables based on an <code class="directive"><If></code>
<code>ap_expr</code>. These expressions will be evaluated at runtime,
and applied <em>env-variable</em> in the same fashion as <code class="directive">SetEnvIf</code>.</p>
<div class="example"><p><code>
SetEnvIfExpr "tolower(req('X-Sendfile')) == 'd:\images\very_big.iso')" iso_delivered
</code></p></div>
<p>This would set the environment variable <code>iso_delivered</code>
every time our application attempts to send it via <code>X-Sendfile</code></p>
<p>A more useful example would be to set the variable rfc1918 if the
remote IP address is a private address according to RFC 1918:</p>
<div class="example"><p><code>
</code></p></div>
<h3>See also</h3>
<ul>
for a complete reference and more examples.</li>
<li><code class="directive"><If></code> can be used to achive similar
results.</li>
</ul>
</div>
<div class="directive-section"><h2><a name="SetEnvIfNoCase" id="SetEnvIfNoCase">SetEnvIfNoCase</a> <a name="setenvifnocase" id="setenvifnocase">Directive</a></h2>
<table class="directive">
<tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Sets environment variables based on attributes of the request
without respect to case</td></tr>
<tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>SetEnvIfNoCase <em>attribute regex
[!]env-variable</em>[=<em>value</em>]
[[!]<em>env-variable</em>[=<em>value</em>]] ...</code></td></tr>
<tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
</table>
<p>The <code class="directive">SetEnvIfNoCase</code> is semantically identical to
the <code class="directive"><a href="#setenvif">SetEnvIf</a></code> directive,
and differs only in that the regular expression matching is
performed in a case-insensitive manner. For example:</p>
<div class="example"><p><code>
SetEnvIfNoCase Host Example\.Org site=example
</code></p></div>
<p>This will cause the <code>site</code> environment variable
to be set to "<code>example</code>" if the HTTP request header
field <code>Host:</code> was included and contained
combination.</p>
</div>
</div>
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<a href="/tr/mod/mod_setenvif.html" hreflang="tr" rel="alternate" title="T�rk�e"> tr </a></p>
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