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| author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-27 06:33:50 +0000 |
|---|---|---|
| committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-27 06:33:50 +0000 |
| commit | fe39ffb8b90ae4e002ed73fe98617cd590abb467 (patch) | |
| tree | b80e5956907d8aeaaffe4e4f0c068c0e6157ce8b /docs/manual/expr.html.en | |
| parent | Initial commit. (diff) | |
| download | apache2-fe39ffb8b90ae4e002ed73fe98617cd590abb467.tar.xz apache2-fe39ffb8b90ae4e002ed73fe98617cd590abb467.zip | |
Adding upstream version 2.4.56.upstream/2.4.56upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to '')
| -rw-r--r-- | docs/manual/expr.html.en | 657 |
1 files changed, 657 insertions, 0 deletions
diff --git a/docs/manual/expr.html.en b/docs/manual/expr.html.en new file mode 100644 index 0000000..5520c33 --- /dev/null +++ b/docs/manual/expr.html.en @@ -0,0 +1,657 @@ +<?xml version="1.0" encoding="UTF-8"?> +<!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> +<meta content="text/html; charset=UTF-8" http-equiv="Content-Type" /> +<!-- + XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX + This file is generated from xml source: DO NOT EDIT + XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX + --> +<title>Expressions in Apache HTTP Server - Apache HTTP Server Version 2.4</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 rel="stylesheet" type="text/css" href="./style/css/prettify.css" /> +<script src="./style/scripts/prettify.min.js" type="text/javascript"> +</script> + +<link href="./images/favicon.ico" rel="shortcut icon" /></head> +<body id="manual-page"><div id="page-header"> +<p class="menu"><a href="./mod/">Modules</a> | <a href="./mod/directives.html">Directives</a> | <a href="http://wiki.apache.org/httpd/FAQ">FAQ</a> | <a href="./glossary.html">Glossary</a> | <a href="./sitemap.html">Sitemap</a></p> +<p class="apache">Apache HTTP Server Version 2.4</p> +<img alt="" src="./images/feather.png" /></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 2.4</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> | +<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 a condition in the different modules of the Apache + HTTP Server. There is some ongoing effort to only use a single + variant, called <em>ap_expr</em>, 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"><a href="https://www.apache.org/foundation/contributing.html" class="badge"><img src="https://www.apache.org/images/SupportApache-small.png" alt="Support Apache!" /></a><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> +<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> +<li><img alt="" src="./images/down.gif" /> <a href="#compatibility">Version History</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/core.html#errordocument">ErrorDocument</a></code></li><li><code class="directive"><a href="./mod/mod_alias.html#alias">Alias</a></code></li><li><code class="directive"><a href="./mod/mod_alias.html#scriptalias">ScriptAlias</a></code></li><li><code class="directive"><a href="./mod/mod_alias.html#redirect">Redirect</a></code></li><li><code class="directive"><a href="./mod/mod_auth_basic.html#authbasicfake">AuthBasicFake</a></code></li><li><code class="directive"><a href="./mod/mod_auth_form.html#authformloginrequiredlocation">AuthFormLoginRequiredLocation</a></code></li><li><code class="directive"><a href="./mod/mod_auth_form.html#authformloginsuccesslocation">AuthFormLoginSuccessLocation</a></code></li><li><code class="directive"><a href="./mod/mod_auth_form.html#authformlogoutlocation">AuthFormLogoutLocation</a></code></li><li><code class="directive"><a href="./mod/mod_authn_core.html#authname">AuthName</a></code></li><li><code class="directive"><a href="./mod/mod_authn_core.html#authtype">AuthType</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><a href="mod/mod_authnz_ldap.html#requser">Require ldap-user</a></li><li><a href="mod/mod_authnz_ldap.html#reqgroup">Require ldap-group</a></li><li><a href="mod/mod_authnz_ldap.html#reqdn">Require ldap-dn</a></li><li><a href="mod/mod_authnz_ldap.html#reqattribute">Require ldap-attribute</a></li><li><a href="mod/mod_authnz_ldap.html#reqfilter">Require ldap-filter</a></li><li><a href="mod/mod_authz_dbd.html#reqgroup">Require dbd-group</a></li><li><a href="mod/mod_authz_dbm.html#reqgroup">Require dbm-group</a></li><li><a href="mod/mod_authz_groupfile.html#reqgroup">Require group</a></li><li><a href="mod/mod_authz_host.html#reqhost">Require host</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><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 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 point 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 point in + the BNF is <code>string</code>. + </p> +<blockquote> +<pre>expr ::= "<strong>true</strong>" | "<strong>false</strong>" + | "<strong>!</strong>" expr + | expr "<strong>&&</strong>" expr + | expr "<strong>||</strong>" expr + | "<strong>(</strong>" expr "<strong>)</strong>" + | comp + +comp ::= stringcomp + | integercomp + | unaryop word + | word binaryop word + | word "<strong>in</strong>" "<strong>{</strong>" wordlist "<strong>}</strong>" + | word "<strong>in</strong>" listfunction + | word "<strong>=~</strong>" regex + | word "<strong>!~</strong>" regex + + +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 + | word "<strong>-lt</strong>" word | word "<strong>lt</strong>" word + | word "<strong>-le</strong>" word | word "<strong>le</strong>" word + | word "<strong>-gt</strong>" word | word "<strong>gt</strong>" word + | word "<strong>-ge</strong>" word | word "<strong>ge</strong>" word + +wordlist ::= word + | wordlist "<strong>,</strong>" word + +word ::= word "<strong>.</strong>" word + | digit + | "<strong>'</strong>" string "<strong>'</strong>" + | "<strong>"</strong>" string "<strong>"</strong>" + | variable + | rebackref + | function + +string ::= stringpart + | 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>"</pre> +</blockquote> + +</div><div class="top"><a href="#page-header"><img alt="top" src="./images/up.gif" /></a></div> +<div class="section"> +<h2><a name="vars" id="vars">Variables</a></h2> + + + <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> +<tr class="odd"><td><code>HTTP_COOKIE</code></td></tr> +<tr><td><code>HTTP_FORWARDED</code></td></tr> +<tr class="odd"><td><code>HTTP_HOST</code></td></tr> +<tr><td><code>HTTP_PROXY_CONNECTION</code></td></tr> +<tr class="odd"><td><code>HTTP_REFERER</code></td></tr> +<tr><td><code>HTTP_USER_AGENT</code></td></tr> +</table> + + <p>Other request related variables</p> + + <table class="bordered"><tr class="header"><th>Name</th><th>Description</th></tr> +<tr><td><code>REQUEST_METHOD</code></td> + <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>The scheme part of the request's URI</td></tr> +<tr><td><code>REQUEST_URI</code></td> + <td>The path part of the request's URI</td></tr> +<tr class="odd"><td><code>DOCUMENT_URI</code></td> + <td>Same as <code>REQUEST_URI</code></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_PORT</code></td> + <td>The port of the remote host (2.4.26 and later)</td></tr> +<tr class="odd"><td><code>REMOTE_HOST</code></td> + <td>The host name of the remote host</td></tr> +<tr><td><code>REMOTE_USER</code></td> + <td>The name of the authenticated user, if any (not available during <code class="directive"><If></code>)</td></tr> +<tr class="odd"><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><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 class="odd"><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><td><code>SERVER_ADMIN</code></td> + <td>The <code class="directive"><a href="./mod/core.html#serveradmin">ServerAdmin</a></code> of + the current vhost</td></tr> +<tr class="odd"><td><code>SERVER_PROTOCOL</code></td> + <td>The protocol used by the request</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>The content type of the response (not available during <code class="directive"><If></code>)</td></tr> +<tr class="odd"><td><code>HANDLER</code></td> + <td>The name of the <a href="handler.html">handler</a> creating + the response</td></tr> +<tr><td><code>HTTP2</code></td> + <td>"<code>on</code>" if the request uses http/2, + "<code>off</code>" otherwise</td></tr> +<tr class="odd"><td><code>HTTPS</code></td> + <td>"<code>on</code>" if the request uses https, + "<code>off</code>" otherwise</td></tr> +<tr><td><code>IPV6</code></td> + <td>"<code>on</code>" if the connection uses IPv6, + "<code>off</code>" otherwise</td></tr> +<tr class="odd"><td><code>REQUEST_STATUS</code></td> + <td>The HTTP error status of the request (not available during <code class="directive"><If></code>)</td></tr> +<tr><td><code>REQUEST_LOG_ID</code></td> + <td>The error log id of the request (see + <code class="directive"><a href="./mod/core.html#errorlogformat">ErrorLogFormat</a></code>)</td></tr> +<tr class="odd"><td><code>CONN_LOG_ID</code></td> + <td>The error log id of the connection (see + <code class="directive"><a href="./mod/core.html#errorlogformat">ErrorLogFormat</a></code>)</td></tr> +<tr><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> +<tr class="odd"><td><code>CONTEXT_PREFIX</code></td> + <td /></tr> +<tr><td><code>CONTEXT_DOCUMENT_ROOT</code></td> + <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>The current year (e.g. <code>2010</code>)</td></tr> +<tr class="odd"><td><code>TIME_MON</code></td> + <td>The current month (<code>01</code>, ..., <code>12</code>)</td></tr> +<tr><td><code>TIME_DAY</code></td> + <td>The current day of the month (<code>01</code>, ...)</td></tr> +<tr class="odd"><td><code>TIME_HOUR</code></td> + <td>The hour part of the current time + (<code>00</code>, ..., <code>23</code>)</td></tr> +<tr><td><code>TIME_MIN</code></td> + <td>The minute part of the current time </td></tr> +<tr class="odd"><td><code>TIME_SEC</code></td> + <td>The second part of the current time </td></tr> +<tr><td><code>TIME_WDAY</code></td> + <td>The day of the week (starting with <code>0</code> + for Sunday)</td></tr> +<tr class="odd"><td><code>TIME</code></td> + <td>The date and time in the format + <code>20101231235959</code></td></tr> +<tr><td><code>SERVER_SOFTWARE</code></td> + <td>The server version string</td></tr> +<tr class="odd"><td><code>API_VERSION</code></td> + <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> + + + <p>With the exception of some built-in comparison operators, binary + operators have the form "<code>-[a-zA-Z][a-zA-Z0-9_]+</code>", i.e. a + 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>String equality</td></tr> +<tr class="odd"><td><code>!=</code></td> + <td /> + <td>String inequality</td></tr> +<tr><td><code><</code></td> + <td /> + <td>String less than</td></tr> +<tr class="odd"><td><code><=</code></td> + <td /> + <td>String less than or equal</td></tr> +<tr><td><code>></code></td> + <td /> + <td>String greater than</td></tr> +<tr class="odd"><td><code>>=</code></td> + <td /> + <td>String greater than or equal</td></tr> +<tr><td><code>=~</code></td> + <td /> + <td>String matches the regular expression</td></tr> +<tr class="odd"><td><code>!~</code></td> + <td /> + <td>String does not match the regular expression</td></tr> +<tr><td><code>-eq</code></td> + <td><code>eq</code></td> + <td>Integer equality</td></tr> +<tr class="odd"><td><code>-ne</code></td> + <td><code>ne</code></td> + <td>Integer inequality</td></tr> +<tr><td><code>-lt</code></td> + <td><code>lt</code></td> + <td>Integer less than</td></tr> +<tr class="odd"><td><code>-le</code></td> + <td><code>le</code></td> + <td>Integer less than or equal</td></tr> +<tr><td><code>-gt</code></td> + <td><code>gt</code></td> + <td>Integer greater than</td></tr> +<tr class="odd"><td><code>-ge</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 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><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> + + + <p>Normal string-valued functions take one string as argument and return + 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><th>Special notes</th></tr> +<tr><td><code>req</code>, <code>http</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 (most response headers will not yet be set + during <code class="directive"><If></code>)</td><td /></tr> +<tr class="odd"><td><code>reqenv</code></td> + <td>Lookup request environment variable (as a shortcut, + <code>v</code> can also be used to access variables). + </td> + <td>ordering</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>ordering</td></tr> +<tr><td><code>env</code></td> + <td>Return first match of <code>note</code>, <code>reqenv</code>, + <code>osenv</code></td><td>ordering</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 upper 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>base64</code></td> + <td>Encode the string using base64 encoding</td><td /></tr> +<tr><td><code>unbase64</code></td> + <td>Decode base64 encoded string, return truncated string if 0x00 is + found</td><td /></tr> +<tr class="odd"><td><code>md5</code></td> + <td>Hash the string using MD5, then encode the hash with hexadecimal + encoding</td><td /></tr> +<tr><td><code>sha1</code></td> + <td>Hash the string using SHA1, then encode the hash with hexadecimal + encoding</td><td /></tr> +<tr class="odd"><td><code>file</code></td> + <td>Read contents from a file (including line endings, when present) + </td><td>restricted</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>restricted</td></tr> +<tr class="odd"><td><code>ldap</code></td> + <td>Escape characters as required by LDAP distinguished name escaping + (RFC4514) and LDAP filter escaping (RFC4515).<br /> + (Available in httpd 2.4.53 and later)</td><td /></tr> +</table> + + <p>The functions marked as "restricted" in the final column are not + available in some modules like <code class="module"><a href="./mod/mod_include.html">mod_include</a></code>.</p> + + <p>The functions marked as "ordering" in the final column require some + consideration for the ordering of different components of the server, + especially when the function is used within the + <<code class="directive"><a href="./mod/core.html#if">If</a></code>> directive which is + evaluated relatively early.</p> + <div class="note"> + <h3>Environment variable ordering</h3> + When environment variables are looked up within an + <<code class="directive"><a href="./mod/core.html#if">If</a></code>> condition, it's important + to consider how extremely early in request processing that this + resolution occurs. As a guideline, any directive defined outside of virtual host + context (directory, location, htaccess) is not likely to have yet had a + chance to execute. <code class="directive"><a href="./mod/mod_setenvif.html#setenvif">SetEnvIf</a></code> + in virtual host scope is one directive that runs prior to this resolution + <br /> + <br /> + When <code>reqenv</code> is used outside of <<code class="directive"><a href="./mod/core.html#if">If</a></code>>, the resolution will generally occur later, but the + exact timing depends on the directive the expression has been used within. + </div> + + <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. <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> + +# Check a HTTP header for a list of values +<If "%{HTTP:X-example-header} in { 'foo', 'bar', 'baz' }"> + Header set matched true +</If> + +# Check an environment variable for a regular expression, negated. +<If "! reqenv('REDIRECT_FOO') =~ /bar/"> + Header set matched true +</If> + +# Check result of URI mapping by running in Directory context with -f +<Directory "/var/www"> + AddEncoding x-gzip gz +<If "-f '%{REQUEST_FILENAME}.unzipme' && ! %{HTTP:Accept-Encoding} =~ /gzip/"> + SetOutputFilter INFLATE +</If> +</Directory> + +# Check against the client IP +<If "-R '192.168.1.0/24'"> + Header set matched true +</If> + +# Function example in boolean context +<If "md5('foo') == 'acbd18db4cc2f85cedef654fccc4a4d8'"> + Header set checksum-matched true +</If> + +# Function example in string context +Header set foo-checksum "expr=%{md5:foo}" + +# This delays the evaluation of the condition clause compared to <If> +Header always set CustomHeader my-value "expr=%{REQUEST_URI} =~ m#^/special_path\.php$#" + +# Conditional logging +CustomLog logs/access-errors.log common "expr=%{REQUEST_STATUS} >= 400" +CustomLog logs/access-errors-specific.log common "expr=%{REQUEST_STATUS} -in {'405','410'}"</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 wordlist</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 class="top"><a href="#page-header"><img alt="top" src="./images/up.gif" /></a></div> +<div class="section"> +<h2><a name="compatibility" id="compatibility">Version History</a></h2> + + <p>The <code>req_novary</code> <a href="#functions">function</a> + is available for versions 2.4.4 and later.</p> +</div></div> +<div class="bottomlang"> +<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><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. 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