<title>Expressions in Apache HTTP Server - Apache HTTP Server</title>
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-<p class="apache">Apache HTTP Server Version 2.3</p>
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+<p class="apache">Apache HTTP Server Version 2.5</p>
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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></div><div id="page-content"><div id="preamble"><h1>Expressions in Apache HTTP Server</h1>
+<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 2.5</a></div><div id="page-content"><div id="preamble"><h1>Expressions in Apache HTTP Server</h1>
<div class="toplang">
-<p><span>Available Languages: </span><a href="./en/expr.html" title="English"> en </a></p>
+<p><span>Available Languages: </span><a href="./en/expr.html" title="English"> en </a> |
+<a href="./fr/expr.html" hreflang="fr" rel="alternate" title="Français"> fr </a></p>
</div>
<p>Historically, there are several syntax variants for expressions used to express
for all configuration directives.
This document describes the <em>ap_expr</em> expression parser.
</p>
+ <p>The <em>ap_expr</em> expression is intended to replace most other
+ expression variants in HTTPD. For example, the deprecated
+ <code class="directive"><a href="./mod/mod_ssl.html#sslrequire">SSLRequire</a></code> expressions can be
+ replaced by <a href="mod/mod_authz_core.html#reqexpr">Require expr</a>.
+ </p>
</div>
-<div id="quickview"><ul id="toc"><li><img alt="" src="./images/down.gif" /> <a href="#grammar">Grammar in BNF notation</a></li>
+<div id="quickview"><ul id="toc"><li><img alt="" src="./images/down.gif" /> <a href="#grammar">Grammar in Backus-Naur Form notation</a></li>
<li><img alt="" src="./images/down.gif" /> <a href="#vars">Variables</a></li>
<li><img alt="" src="./images/down.gif" /> <a href="#binop">Binary operators</a></li>
<li><img alt="" src="./images/down.gif" /> <a href="#unnop">Unary operators</a></li>
<li><img alt="" src="./images/down.gif" /> <a href="#functions">Functions</a></li>
-</ul></div>
+<li><img alt="" src="./images/down.gif" /> <a href="#examples">Example expressions</a></li>
+<li><img alt="" src="./images/down.gif" /> <a href="#other">Other</a></li>
+<li><img alt="" src="./images/down.gif" /> <a href="#sslrequire">Comparison with SSLRequire</a></li>
+</ul><h3>See also</h3><ul class="seealso"><li><code class="directive"><a href="./mod/core.html#if"><If></a></code></li><li><code class="directive"><a href="./mod/core.html#elseif"><ElseIf></a></code></li><li><code class="directive"><a href="./mod/core.html#else"><Else></a></code></li><li><code class="directive"><a href="./mod/mod_rewrite.html#rewritecond">RewriteCond</a></code></li><li><code class="directive"><a href="./mod/mod_setenvif.html#setenvifexpr">SetEnvIfExpr</a></code></li><li><code class="directive"><a href="./mod/mod_headers.html#header">Header</a></code></li><li><code class="directive"><a href="./mod/mod_headers.html#requestheader">RequestHeader</a></code></li><li><code class="directive"><a href="./mod/mod_filter.html#filterprovider">FilterProvider</a></code></li><li><a href="mod/mod_authz_core.html#reqexpr">Require expr</a></li><li><code class="directive"><a href="./mod/mod_ssl.html#sslrequire">SSLRequire</a></code></li><li><code class="directive"><a href="./mod/mod_log_debug.html#logmessage">LogMessage</a></code></li><li><code class="module"><a href="./mod/mod_include.html">mod_include</a></code></li></ul><ul class="seealso"><li><a href="#comments_section">Comments</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="grammar" id="grammar">Grammar in BNF notation</a></h2>
+<h2><a name="grammar" id="grammar">Grammar in Backus-Naur Form notation</a></h2>
+ <p><a href="http://en.wikipedia.org/wiki/Backus%E2%80%93Naur_Form">Backus-Naur Form</a> (BNF) is a notation
+ technique for context-free grammars, often used to describe the syntax of languages used in computing.
+ In most cases, expressions are used to express boolean values.
+ For these, the starting boint in the BNF is <code>expr</code>. However, a few directives
+ like <code class="directive"><a href="./mod/mod_log_debug.html#logmessage">LogMessage</a></code> accept expressions
+ that evaluate to a string value. For those, the starting boint in the BNF is <code>string</code>.
+ </p>
<blockquote>
<pre>
expr ::= "<strong>true</strong>" | "<strong>false</strong>"
| word "<strong>!~</strong>" regex
-stringcomp ::= word "<strong>==</strong>" word | word "<strong>eq</strong>" word
- | word "<strong>!=</strong>" word | word "<strong>ne</strong>" word
- | word "<strong><</strong>" word | word "<strong>lt</strong>" word
- | word "<strong><=</strong>" word | word "<strong>le</strong>" word
- | word "<strong>></strong>" word | word "<strong>gt</strong>" word
- | word "<strong>>=</strong>" word | word "<strong>ge</strong>" word
+stringcomp ::= word "<strong>==</strong>" word
+ | word "<strong>!=</strong>" word
+ | word "<strong><</strong>" word
+ | word "<strong><=</strong>" word
+ | word "<strong>></strong>" word
+ | word "<strong>>=</strong>" word
integercomp ::= word "<strong>-eq</strong>" word | word "<strong>eq</strong>" word
| word "<strong>-ne</strong>" word | word "<strong>ne</strong>" word
| "<strong>'</strong>" string "<strong>'</strong>"
| "<strong>"</strong>" string "<strong>"</strong>"
| variable
+ | rebackref
| function
string ::= stringpart
stringpart ::= cstring
| variable
+ | rebackref
cstring ::= ...
digit ::= [0-9]+
variable ::= "<strong>%{</strong>" varname "<strong>}</strong>"
| "<strong>%{</strong>" funcname "<strong>:</strong>" funcargs "<strong>}</strong>"
+rebackref ::= "<strong>$</strong>" [0-9]
+
function ::= funcname "<strong>(</strong>" word "<strong>)</strong>"
listfunction ::= listfuncname "<strong>(</strong>" word "<strong>)</strong>"
<div class="section">
<h2><a name="vars" id="vars">Variables</a></h2>
-<p>XXX: not all vars are available in all request phases</p>
-
- <p>Request headers (XXX:see req function)</p>
+
+ <p>The expression parser provides a number of variables of the form
+ <code>%{HTTP_HOST}</code>. Note that the value of a variable may depend
+ on the phase of the request processing in which it is evaluated. For
+ example, an expression used in an <code class="directive"><If ></code>
+ directive is evaluated before authentication is done. Therefore,
+ <code>%{REMOTE_USER}</code> will not be set in this case.</p>
+
+ <p>The following variables provide the values of the named HTTP request
+ headers. The values of other headers can be obtained with the
+ <code>req</code> <a href="#functions">function</a>. Using these
+ variables may cause the header name to be added to the Vary
+ header of the HTTP response, except where otherwise noted for the
+ directive accepting the expression. The <code>req_novary</code>
+ <a href="#functions">function</a> may be used to circumvent this
+ behavior.</p>
<table class="bordered"><tr class="header"><th>Name</th></tr>
<tr><td><code>HTTP_ACCEPT</code></td></tr>
<table class="bordered"><tr class="header"><th>Name</th><th>Description</th></tr>
<tr><td><code>REQUEST_METHOD</code></td>
- <td /></tr>
+ <td>The HTTP method of the incoming request (e.g.
+ <code>GET</code>)</td></tr>
<tr class="odd"><td><code>REQUEST_SCHEME</code></td>
- <td /></tr>
+ <td>The scheme part of the request's URI</td></tr>
<tr><td><code>REQUEST_URI</code></td>
- <td /></tr>
-<tr class="odd"><td><code>REQUEST_FILENAME</code></td>
- <td /></tr>
+ <td>The path part of the request's URI</td></tr>
+<tr class="odd"><td><code>DOCUMENT_URI</code></td>
+ <td>Same as REQUEST_URI</td></tr>
+<tr><td><code>REQUEST_FILENAME</code></td>
+ <td>The full local filesystem path to the file or script matching the
+ request, if this has already been determined by the server at the
+ time <code>REQUEST_FILENAME</code> is referenced. Otherwise, such
+ as when used in virtual host context, the same value as
+ <code>REQUEST_URI</code> </td></tr>
+<tr class="odd"><td><code>SCRIPT_FILENAME</code></td>
+ <td>Same as <code>REQUEST_FILENAME</code></td></tr>
+<tr><td><code>LAST_MODIFIED</code></td>
+ <td>The date and time of last modification of the file in the format
+ <code>20101231235959</code>, if this has already been determined by
+ the server at the time <code>LAST_MODIFIED</code> is referenced.
+ </td></tr>
+<tr class="odd"><td><code>SCRIPT_USER</code></td>
+ <td>The user name of the owner of the script.</td></tr>
+<tr><td><code>SCRIPT_GROUP</code></td>
+ <td>The group name of the group of the script.</td></tr>
+<tr class="odd"><td><code>PATH_INFO</code></td>
+ <td>The trailing path name information, see
+ <code class="directive"><a href="./mod/core.html#acceptpathinfo">AcceptPathInfo</a></code></td></tr>
+<tr><td><code>QUERY_STRING</code></td>
+ <td>The query string of the current request</td></tr>
+<tr class="odd"><td><code>IS_SUBREQ</code></td>
+ <td>"<code>true</code>" if the current request is a subrequest,
+ "<code>false</code>" otherwise</td></tr>
+<tr><td><code>THE_REQUEST</code></td>
+ <td>The complete request line (e.g.,
+ "<code>GET /index.html HTTP/1.1</code>")</td></tr>
+<tr class="odd"><td><code>REMOTE_ADDR</code></td>
+ <td>The IP address of the remote host</td></tr>
<tr><td><code>REMOTE_HOST</code></td>
- <td /></tr>
-<tr class="odd"><td><code>REMOTE_IDENT</code></td>
- <td /></tr>
-<tr><td><code>REMOTE_USER</code></td>
- <td /></tr>
+ <td>The host name of the remote host</td></tr>
+<tr class="odd"><td><code>REMOTE_USER</code></td>
+ <td>The name of the authenticated user (if any)</td></tr>
+<tr><td><code>REMOTE_IDENT</code></td>
+ <td>The user name set by <code class="module"><a href="./mod/mod_ident.html">mod_ident</a></code></td></tr>
+<tr class="odd"><td><code>SERVER_NAME</code></td>
+ <td>The <code class="directive"><a href="./mod/core.html#servername">ServerName</a></code> of
+ the current vhost</td></tr>
+<tr><td><code>SERVER_PORT</code></td>
+ <td>The server port of the current vhost, see
+ <code class="directive"><a href="./mod/core.html#servername">ServerName</a></code></td></tr>
<tr class="odd"><td><code>SERVER_ADMIN</code></td>
- <td /></tr>
-<tr><td><code>SERVER_NAME</code></td>
- <td /></tr>
-<tr class="odd"><td><code>SERVER_PORT</code></td>
- <td /></tr>
+ <td>The <code class="directive"><a href="./mod/core.html#serveradmin">ServerAdmin</a></code> of
+ the current vhost</td></tr>
<tr><td><code>SERVER_PROTOCOL</code></td>
- <td /></tr>
-<tr class="odd"><td><code>SCRIPT_FILENAME</code></td>
- <td /></tr>
-<tr><td><code>PATH_INFO</code></td>
- <td /></tr>
-<tr class="odd"><td><code>QUERY_STRING</code></td>
- <td /></tr>
-<tr><td><code>IS_SUBREQ</code></td>
- <td /></tr>
-<tr class="odd"><td><code>DOCUMENT_ROOT</code></td>
- <td /></tr>
-<tr><td><code>AUTH_TYPE</code></td>
- <td /></tr>
-<tr class="odd"><td><code>THE_REQUEST</code></td>
- <td /></tr>
+ <td>The protocol used by the request (e.g. HTTP/1.1). In some types of
+ internal subrequests, this variable has the value
+ <code>INCLUDED</code>.</td></tr>
+<tr class="odd"><td><code>SERVER_PROTOCOL_VERSION</code></td>
+ <td>A number that encodes the HTTP version of the request:
+ <code>1000 * major + minor</code>. For example, <code>1001</code>
+ corresponds to HTTP/1.1 and <code>9</code> corresponds
+ to HTTP/0.9</td></tr>
+<tr><td><code>SERVER_PROTOCOL_VERSION_MAJOR</code></td>
+ <td>The major version part of the HTTP version of the request,
+ e.g. <code>1</code> for HTTP/1.0</td></tr>
+<tr class="odd"><td><code>SERVER_PROTOCOL_VERSION_MINOR</code></td>
+ <td>The minor version part of the HTTP version of the request,
+ e.g. <code>0</code> for HTTP/1.0</td></tr>
+<tr><td><code>DOCUMENT_ROOT</code></td>
+ <td>The <code class="directive"><a href="./mod/core.html#documentroot">DocumentRoot</a></code> of
+ the current vhost</td></tr>
+<tr class="odd"><td><code>AUTH_TYPE</code></td>
+ <td>The configured <code class="directive"><a href="./mod/mod_authn_core.html#authtype">AuthType</a></code>
+ (e.g. "<code>basic</code>")</td></tr>
<tr><td><code>CONTENT_TYPE</code></td>
- <td /></tr>
+ <td>The content type of the response</td></tr>
<tr class="odd"><td><code>HANDLER</code></td>
- <td /></tr>
-<tr><td><code>REMOTE_ADDR</code></td>
- <td /></tr>
-<tr class="odd"><td><code>HTTPS</code></td>
- <td /></tr>
-<tr><td><code>IPV6</code></td>
- <td /></tr>
+ <td>The name of the <a href="handler.html">handler</a> creating
+ the response</td></tr>
+<tr><td><code>HTTPS</code></td>
+ <td>"<code>on</code>" if the request uses https,
+ "<code>off</code>" otherwise</td></tr>
+<tr class="odd"><td><code>IPV6</code></td>
+ <td>"<code>on</code>" if the connection uses IPv6,
+ "<code>off</code>" otherwise</td></tr>
+<tr><td><code>REQUEST_STATUS</code></td>
+ <td>The HTTP error status of the request</td></tr>
<tr class="odd"><td><code>REQUEST_LOG_ID</code></td>
- <td /></tr>
+ <td>The error log id of the request (see
+ <code class="directive"><a href="./mod/core.html#errorlogformat">ErrorLogFormat</a></code>)</td></tr>
<tr><td><code>CONN_LOG_ID</code></td>
- <td /></tr>
+ <td>The error log id of the connection (see
+ <code class="directive"><a href="./mod/core.html#errorlogformat">ErrorLogFormat</a></code>)</td></tr>
+<tr class="odd"><td><code>CONN_REMOTE_ADDR</code></td>
+ <td>The peer IP address of the connection (see the
+ <code class="module"><a href="./mod/mod_remoteip.html">mod_remoteip</a></code> module)</td></tr>
</table>
<p>Misc variables</p>
<table class="bordered"><tr class="header"><th>Name</th><th>Description</th></tr>
<tr><td><code>TIME_YEAR</code></td>
- <td /></tr>
+ <td>The current year (e.g. <code>2010</code>)</td></tr>
<tr class="odd"><td><code>TIME_MON</code></td>
- <td /></tr>
+ <td>The current month (<code>1</code>, ..., <code>12</code>)</td></tr>
<tr><td><code>TIME_DAY</code></td>
- <td /></tr>
+ <td>The current day of the month</td></tr>
<tr class="odd"><td><code>TIME_HOUR</code></td>
- <td /></tr>
+ <td>The hour part of the current time
+ (<code>0</code>, ..., <code>23</code>)</td></tr>
<tr><td><code>TIME_MIN</code></td>
- <td /></tr>
+ <td>The minute part of the current time </td></tr>
<tr class="odd"><td><code>TIME_SEC</code></td>
- <td /></tr>
+ <td>The second part of the current time </td></tr>
<tr><td><code>TIME_WDAY</code></td>
- <td /></tr>
+ <td>The day of the week (starting with <code>0</code>
+ for Sunday)</td></tr>
<tr class="odd"><td><code>TIME</code></td>
- <td /></tr>
+ <td>The date and time in the format <code>20101231235959</code></td></tr>
<tr><td><code>SERVER_SOFTWARE</code></td>
- <td /></tr>
+ <td>The server version string</td></tr>
<tr class="odd"><td><code>API_VERSION</code></td>
- <td /></tr>
+ <td>The date of the API version (module magic number)</td></tr>
</table>
+ <p>Some modules register additional variables, see e.g. <code class="module"><a href="./mod/mod_ssl.html">mod_ssl</a></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="binop" id="binop">Binary operators</a></h2>
minus and at least two characters. The name is not case sensitive.
Modules may register additional binary operators.</p>
+ <h3><a name="comp" id="comp">Comparison operators</a></h3>
+
+
<table class="bordered"><tr class="header"><th>Name</th><th>Alternative</th> <th>Description</th></tr>
<tr><td><code>==</code></td>
<td><code>=</code></td>
<td><code>ge</code></td>
<td>Integer greater than or equal</td></tr>
</table>
+
+
+ <h3><a name="binaryother" id="binaryother">Other binary operators</a></h3>
+
+
+ <table class="bordered"><tr class="header"><th>Name</th><th>Description</th></tr>
+<tr><td><code>-ipmatch</code></td>
+ <td>IP address matches address/netmask</td></tr>
+<tr class="odd"><td><code>-strmatch</code></td>
+ <td>left string matches pattern given by right string (containing
+ wildcards *, ?, [])</td></tr>
+<tr><td><code>-strcmatch</code></td>
+ <td>same as <code>-strmatch</code>, but case insensitive</td></tr>
+<tr class="odd"><td><code>-fnmatch</code></td>
+ <td>same as <code>-strmatch</code>, but slashes are not matched by
+ wildcards</td></tr>
+</table>
+
</div><div class="top"><a href="#page-header"><img alt="top" src="./images/up.gif" /></a></div>
<div class="section">
<h2><a name="unnop" id="unnop">Unary operators</a></h2>
- <p>Unary operators have the form "<code>-[a-zA-Z]</code>", i.e. a
- minus and one character. The name <em>is</em> case sensitive.
+ <p>Unary operators take one argument and have the form
+ "<code>-[a-zA-Z]</code>", i.e. a minus and one character.
+ The name <em>is</em> case sensitive.
Modules may register additional unary operators.</p>
- <table class="bordered"><tr class="header"><th>Name</th><th>Description</th></tr>
-<tr><td><code>-n</code></td>
- <td>String is not empty</td></tr>
-<tr class="odd"><td><code>-z</code></td>
- <td>String is empty</td></tr>
+ <table class="bordered"><tr class="header"><th>Name</th><th>Description</th><th>Restricted</th></tr>
+<tr><td><code>-d</code></td>
+ <td>The argument is treated as a filename.
+ True if the file exists and is a directory</td><td>yes</td></tr>
+<tr class="odd"><td><code>-e</code></td>
+ <td>The argument is treated as a filename.
+ True if the file (or dir or special) exists</td><td>yes</td></tr>
+<tr><td><code>-f</code></td>
+ <td>The argument is treated as a filename.
+ True if the file exists and is regular file</td><td>yes</td></tr>
+<tr class="odd"><td><code>-s</code></td>
+ <td>The argument is treated as a filename.
+ True if the file exists and is not empty</td><td>yes</td></tr>
+<tr><td><code>-L</code></td>
+ <td>The argument is treated as a filename.
+ True if the file exists and is symlink</td><td>yes</td></tr>
+<tr class="odd"><td><code>-h</code></td>
+ <td>The argument is treated as a filename.
+ True if the file exists and is symlink
+ (same as <code>-L</code>)</td><td>yes</td></tr>
+<tr><td><code>-F</code></td>
+ <td>True if string is a valid file, accessible via all the server's
+ currently-configured access controls for that path. This uses an
+ internal subrequest to do the check, so use it with care - it can
+ impact your server's performance!</td><td /></tr>
+<tr class="odd"><td><code>-U</code></td>
+ <td>True if string is a valid URL, accessible via all the server's
+ currently-configured access controls for that path. This uses an
+ internal subrequest to do the check, so use it with care - it can
+ impact your server's performance!</td><td /></tr>
+<tr><td><code>-A</code></td>
+ <td>Alias for <code>-U</code></td><td /></tr>
+<tr class="odd"><td><code>-n</code></td>
+ <td>True if string is not empty</td><td /></tr>
+<tr><td><code>-z</code></td>
+ <td>True if string is empty</td><td /></tr>
+<tr class="odd"><td><code>-T</code></td>
+ <td>False if string is empty, "<code>0</code>", "<code>off</code>",
+ "<code>false</code>", or "<code>no</code>" (case insensitive).
+ True otherwise.</td><td /></tr>
+<tr><td><code>-R</code></td>
+ <td>Same as "<code>%{REMOTE_ADDR} -ipmatch ...</code>", but more efficient
+ </td><td /></tr>
</table>
+ <p>The operators marked as "restricted" are not available in some modules
+ like <code class="module"><a href="./mod/mod_include.html">mod_include</a></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="functions" id="functions">Functions</a></h2>
a string. Functions names are not case sensitive.
Modules may register additional functions.</p>
- <table class="bordered"><tr class="header"><th>Name</th><th>Description</th></tr>
+ <table class="bordered"><tr class="header"><th>Name</th><th>Description</th><th>Restricted</th></tr>
<tr><td><code>req</code>, <code>http</code></td>
- <td>Get HTTP request header</td></tr>
-<tr class="odd"><td><code>resp</code></td>
- <td>Get HTTP response header</td></tr>
-<tr><td><code>reqenv</code></td>
- <td>Lookup request environment variable</td></tr>
-<tr class="odd"><td><code>osenv</code></td>
- <td>Lookup operating system environment variable</td></tr>
-<tr><td><code>note</code></td>
- <td>Lookup request environment variable</td></tr>
-<tr class="odd"><td><code>env</code></td>
+ <td>Get HTTP request header; header names may be added to the Vary
+ header, see below</td><td /></tr>
+<tr class="odd"><td><code>req_novary</code></td>
+ <td>Same as <code>req</code>, but header names will not be added to the
+ Vary header</td><td /></tr>
+<tr><td><code>resp</code></td>
+ <td>Get HTTP response header</td><td /></tr>
+<tr class="odd"><td><code>reqenv</code></td>
+ <td>Lookup request environment variable</td><td /></tr>
+<tr><td><code>osenv</code></td>
+ <td>Lookup operating system environment variable</td><td /></tr>
+<tr class="odd"><td><code>note</code></td>
+ <td>Lookup request note</td><td /></tr>
+<tr><td><code>env</code></td>
<td>Return first match of <code>note</code>, <code>reqenv</code>,
- <code>osenv</code></td></tr>
-<tr><td><code>tolower</code></td>
- <td>Convert string to lower case</td></tr>
-<tr class="odd"><td><code>toupper</code></td>
- <td>Convert string to uppser case</td></tr>
-<tr><td><code>escape</code></td>
- <td>Escape special characters in %hex encoding</td></tr>
-<tr class="odd"><td><code>unescape</code></td>
- <td>Unescape %hex encoded string, leaving URL-special characters encoded (XXX: describe better)</td></tr>
-<tr><td><code>file</code></td>
- <td>Read contents from a file</td></tr>
+ <code>osenv</code></td><td /></tr>
+<tr class="odd"><td><code>tolower</code></td>
+ <td>Convert string to lower case</td><td /></tr>
+<tr><td><code>toupper</code></td>
+ <td>Convert string to uppser case</td><td /></tr>
+<tr class="odd"><td><code>escape</code></td>
+ <td>Escape special characters in %hex encoding</td><td /></tr>
+<tr><td><code>unescape</code></td>
+ <td>Unescape %hex encoded string, leaving encoded slashes alone;
+ return empty string if %00 is found</td><td /></tr>
+<tr class="odd"><td><code>file</code></td>
+ <td>Read contents from a file</td><td>yes</td></tr>
+<tr><td><code>filesize</code></td>
+ <td>Return size of a file (or 0 if file does not exist or is not
+ regular file)</td><td>yes</td></tr>
</table>
+ <p>The functions marked as "restricted" are not available in some modules
+ like <code class="module"><a href="./mod/mod_include.html">mod_include</a></code>.</p>
+
+ <p>When the functions <code>req</code> or <code>http</code> are used,
+ the header name will automatically be added to the Vary header of the
+ HTTP response, except where otherwise noted for the directive accepting
+ the expression. The <code>req_novary</code> function can be used to
+ prevent names from being added to the Vary header.</p>
+
<p>In addition to string-valued functions, there are also list-valued functions which
take one string as argument and return a wordlist, i.e. a list of strings. The wordlist
can be used with the special <code>-in</code> operator.
Functions names are not case sensitive.
Modules may register additional functions.</p>
- <p>There are no built-in list-valued functions. mod_ssl provides
- <code>PeerExtList</code> (XXX: link)</p>
+ <p>There are no built-in list-valued functions. <code class="module"><a href="./mod/mod_ssl.html">mod_ssl</a></code>
+ provides <code>PeerExtList</code>. See the description of
+ <code class="directive"><a href="./mod/mod_ssl.html#sslrequire">SSLRequire</a></code> for details
+ (but <code>PeerExtList</code> is also usable outside
+ of <code class="directive"><a href="./mod/mod_ssl.html#sslrequire">SSLRequire</a></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">Example expressions</a></h2>
+
+
+ <p>The following examples show how expressions might be used to evaluate requests:</p>
+
+ <pre class="prettyprint lang-config">
+# Compare the host name to example.com and redirect to www.example.com if it matches
+<If "%{HTTP_HOST} == 'example.com'">
+ Redirect permanent / http://www.example.com
+</If>
+
+# Force text/plain if requesting a file with the query string contains 'forcetext'
+<If "%{QUERY_STRING} =~ /forcetext/">
+ ForceType text/plain
+</If>
+
+# Only allow access to this content during business hours
+<Directory "/foo/bar/business">
+ Require expr %{TIME_HOUR} -gt 9 && %{TIME_HOUR} -lt 17
+</Directory>
+ </pre>
+
+</div><div class="top"><a href="#page-header"><img alt="top" src="./images/up.gif" /></a></div>
+<div class="section">
+<h2><a name="other" id="other">Other</a></h2>
+
+
+ <table class="bordered"><tr class="header"><th>Name</th><th>Alternative</th> <th>Description</th></tr>
+<tr><td><code>-in</code></td>
+ <td><code>in</code></td>
+ <td>string contained in string list</td></tr>
+<tr class="odd"><td><code>/regexp/</code></td>
+ <td><code>m#regexp#</code></td>
+ <td>Regular expression (the second form allows different delimiters than /)</td></tr>
+<tr><td><code>/regexp/i</code></td>
+ <td><code>m#regexp#i</code></td>
+ <td>Case insensitive regular expression</td></tr>
+<tr class="odd"><td><code>$0 ... $9</code></td>
+ <td />
+ <td>Regular expression backreferences</td></tr>
+</table>
+
+ <h3><a name="rebackref" id="rebackref">Regular expression backreferences</a></h3>
+
+ <p>The strings <code>$0</code> ... <code>$9</code> allow to reference
+ the capture groups from a previously executed, successfully
+ matching regular expressions. They can normally only be used in the
+ same expression as the matching regex, but some modules allow special
+ uses.</p>
+
+</div><div class="top"><a href="#page-header"><img alt="top" src="./images/up.gif" /></a></div>
+<div class="section">
+<h2><a name="sslrequire" id="sslrequire">Comparison with SSLRequire</a></h2>
+
+ <p>The <em>ap_expr</em> syntax is mostly a superset of the syntax of the
+ deprecated <code class="directive"><a href="./mod/mod_ssl.html#sslrequire">SSLRequire</a></code> directive.
+ The differences are described in <code class="directive"><a href="./mod/mod_ssl.html#sslrequire">SSLRequire</a></code>'s documentation.</p>
</div></div>
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+</div><div class="top"><a href="#page-header"><img src="./images/up.gif" alt="top" /></a></div><div class="section"><h2><a id="comments_section" name="comments_section">Comments</a></h2><div class="warning"><strong>Notice:</strong><br />This is not a Q&A section. Comments placed here should be pointed towards suggestions on improving the documentation or server, and may be removed again by our moderators if they are either implemented or considered invalid/off-topic. Questions on how to manage the Apache HTTP Server should be directed at either our IRC channel, #httpd, on Freenode, or sent to our <a href="http://httpd.apache.org/lists.html">mailing lists</a>.</div>
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