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   8 <title>Expressions in Apache HTTP Server - Apache HTTP Server</title>
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  17 <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>
  18 <p class="apache">Apache HTTP Server Version 2.5</p>
  19 <img alt="" src="./images/feather.gif" /></div>
  20 <div class="up"><a href="./"><img title="&lt;-" alt="&lt;-" src="./images/left.gif" /></a></div>
  21 <div id="path">
  22 <a href="http://www.apache.org/">Apache</a> &gt; <a href="http://httpd.apache.org/">HTTP Server</a> &gt; <a href="http://httpd.apache.org/docs/">Documentation</a> &gt; <a href="./">Version 2.5</a></div><div id="page-content"><div id="preamble"><h1>Expressions in Apache HTTP Server</h1>
  23 <div class="toplang">
  24 <p><span>Available Languages: </span><a href="./en/expr.html" title="English">&nbsp;en&nbsp;</a> |
  25 <a href="./fr/expr.html" hreflang="fr" rel="alternate" title="Français">&nbsp;fr&nbsp;</a></p>
  26 </div>
  27
  28     <p>Historically, there are several syntax variants for expressions used to express
  29         a condition in the different modules of the Apache HTTP Server.
  30         There is some ongoing effort to only use a single variant, called <em>ap_expr</em>,
  31         for all configuration directives.
  32         This document describes the <em>ap_expr</em> expression parser.
  33     </p>
  34     <p>The <em>ap_expr</em> expression is intended to replace most other
  35         expression variants in HTTPD. For example, the deprecated
  36         <code class="directive"><a href="./mod/mod_ssl.html#sslrequire">SSLRequire</a></code> expressions can be
  37         replaced by <a href="mod/mod_authz_core.html#reqexpr">Require expr</a>.
  38     </p>
  39   </div>
  40 <div id="quickview"><ul id="toc"><li><img alt="" src="./images/down.gif" /> <a href="#grammar">Grammar in Backus-Naur Form notation</a></li>
  41 <li><img alt="" src="./images/down.gif" /> <a href="#vars">Variables</a></li>
  42 <li><img alt="" src="./images/down.gif" /> <a href="#binop">Binary operators</a></li>
  43 <li><img alt="" src="./images/down.gif" /> <a href="#unnop">Unary operators</a></li>
  44 <li><img alt="" src="./images/down.gif" /> <a href="#functions">Functions</a></li>
  45 <li><img alt="" src="./images/down.gif" /> <a href="#examples">Example expressions</a></li>
  46 <li><img alt="" src="./images/down.gif" /> <a href="#other">Other</a></li>
  47 <li><img alt="" src="./images/down.gif" /> <a href="#sslrequire">Comparison with SSLRequire</a></li>
  48 </ul><h3>See also</h3><ul class="seealso"><li><code class="directive"><a href="./mod/core.html#if">&lt;If&gt;</a></code></li><li><code class="directive"><a href="./mod/core.html#elseif">&lt;ElseIf&gt;</a></code></li><li><code class="directive"><a href="./mod/core.html#else">&lt;Else&gt;</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></div>
  49 <div class="top"><a href="#page-header"><img alt="top" src="./images/up.gif" /></a></div>
  50 <div class="section">
  51 <h2><a name="grammar" id="grammar">Grammar in Backus-Naur Form notation</a></h2>
  52
  53       <p><a href="http://en.wikipedia.org/wiki/Backus%E2%80%93Naur_Form">Backus-Naur Form</a> (BNF) is a notation
  54       technique for context-free grammars, often used to describe the syntax of languages used in computing.
  55       </p>
  56 <blockquote>
  57 <pre>
  58 expr        ::= "<strong>true</strong>" | "<strong>false</strong>"
  59               | "<strong>!</strong>" expr
  60               | expr "<strong>&amp;&amp;</strong>" expr
  61               | expr "<strong>||</strong>" expr
  62               | "<strong>(</strong>" expr "<strong>)</strong>"
  63               | comp
  64
  65 comp        ::= stringcomp
  66               | integercomp
  67               | unaryop word
  68               | word binaryop word
  69               | word "<strong>in</strong>" "<strong>{</strong>" wordlist "<strong>}</strong>"
  70               | word "<strong>in</strong>" listfunction
  71               | word "<strong>=~</strong>" regex
  72               | word "<strong>!~</strong>" regex
  73
  74
  75 stringcomp  ::= word "<strong>==</strong>" word
  76               | word "<strong>!=</strong>" word
  77               | word "<strong>&lt;</strong>"  word
  78               | word "<strong>&lt;=</strong>" word
  79               | word "<strong>&gt;</strong>"  word
  80               | word "<strong>&gt;=</strong>" word
  81
  82 integercomp ::= word "<strong>-eq</strong>" word | word "<strong>eq</strong>" word
  83               | word "<strong>-ne</strong>" word | word "<strong>ne</strong>" word
  84               | word "<strong>-lt</strong>" word | word "<strong>lt</strong>" word
  85               | word "<strong>-le</strong>" word | word "<strong>le</strong>" word
  86               | word "<strong>-gt</strong>" word | word "<strong>gt</strong>" word
  87               | word "<strong>-ge</strong>" word | word "<strong>ge</strong>" word
  88
  89 wordlist    ::= word
  90               | wordlist "<strong>,</strong>" word
  91
  92 word        ::= word "<strong>.</strong>" word
  93               | digit
  94               | "<strong>'</strong>" string "<strong>'</strong>"
  95               | "<strong>"</strong>" string "<strong>"</strong>"
  96               | variable
  97               | rebackref
  98               | function
  99
 100 string      ::= stringpart
 101               | string stringpart
 102
 103 stringpart  ::= cstring
 104               | variable
 105               | rebackref
 106
 107 cstring     ::= ...
 108 digit       ::= [0-9]+
 109
 110 variable    ::= "<strong>%{</strong>" varname "<strong>}</strong>"
 111               | "<strong>%{</strong>" funcname "<strong>:</strong>" funcargs "<strong>}</strong>"
 112
 113 rebackref   ::= "<strong>$</strong>" [0-9]
 114
 115 function     ::= funcname "<strong>(</strong>" word "<strong>)</strong>"
 116
 117 listfunction ::= listfuncname "<strong>(</strong>" word "<strong>)</strong>"
 118 </pre>
 119 </blockquote>
 120
 121 </div><div class="top"><a href="#page-header"><img alt="top" src="./images/up.gif" /></a></div>
 122 <div class="section">
 123 <h2><a name="vars" id="vars">Variables</a></h2>
 124
 125
 126     <p>The expression parser provides a number of variables of the form
 127     <code>%{HTTP_HOST}</code>. Note that the value of a variable may depend
 128     on the phase of the request processing in which it is evaluated.  For
 129     example, an expression used in an <code class="directive">&lt;If &gt;</code>
 130     directive is evaluated before authentication is done. Therefore,
 131     <code>%{REMOTE_USER}</code> will not be set in this case.</p>
 132
 133     <p>The following variables provide the values of the named HTTP request
 134     headers. The values of other headers can be obtained witht the
 135     <code>req</code> <a href="#functions">function</a>.</p>
 136
 137     <table class="bordered"><tr class="header"><th>Name</th></tr>
 138 <tr><td><code>HTTP_ACCEPT</code></td></tr>
 139 <tr class="odd"><td><code>HTTP_FORWARDED</code></td></tr>
 140 <tr><td><code>HTTP_HOST</code></td></tr>
 141 <tr class="odd"><td><code>HTTP_PROXY_CONNECTION</code></td></tr>
 142 <tr><td><code>HTTP_REFERER</code></td></tr>
 143 <tr class="odd"><td><code>HTTP_USER_AGENT</code></td></tr>
 144 </table>
 145
 146     <p>Other request related variables</p>
 147
 148     <table class="bordered"><tr class="header"><th>Name</th><th>Description</th></tr>
 149 <tr><td><code>REQUEST_METHOD</code></td>
 150         <td>The HTTP method of the incoming request (e.g.
 151             <code>GET</code>)</td></tr>
 152 <tr class="odd"><td><code>REQUEST_SCHEME</code></td>
 153         <td>The scheme part of the request's URI</td></tr>
 154 <tr><td><code>REQUEST_URI</code></td>
 155         <td>The path part of the request's URI</td></tr>
 156 <tr class="odd"><td><code>DOCUMENT_URI</code></td>
 157         <td>Same as REQUEST_URI</td></tr>
 158 <tr><td><code>REQUEST_FILENAME</code></td>
 159         <td>The full local filesystem path to the file or script matching the
 160             request, if this has already been determined by the server at the
 161             time <code>REQUEST_FILENAME</code> is referenced. Otherwise, such
 162             as when used in virtual host context, the same value as
 163             <code>REQUEST_URI</code> </td></tr>
 164 <tr class="odd"><td><code>SCRIPT_FILENAME</code></td>
 165         <td>Same as <code>REQUEST_FILENAME</code></td></tr>
 166 <tr><td><code>LAST_MODIFIED</code></td>
 167         <td>The date and time of last modification of the file in the format
 168             <code>20101231235959</code>, if this has already been determined by
 169             the server at the time <code>LAST_MODIFIED</code> is referenced.
 170             </td></tr>
 171 <tr class="odd"><td><code>SCRIPT_USER</code></td>
 172         <td>The user name of the owner of the script.</td></tr>
 173 <tr><td><code>SCRIPT_GROUP</code></td>
 174         <td>The group name of the group of the script.</td></tr>
 175 <tr class="odd"><td><code>PATH_INFO</code></td>
 176         <td>The trailing path name information, see
 177             <code class="directive"><a href="./mod/core.html#acceptpathinfo">AcceptPathInfo</a></code></td></tr>
 178 <tr><td><code>QUERY_STRING</code></td>
 179         <td>The query string of the current request</td></tr>
 180 <tr class="odd"><td><code>IS_SUBREQ</code></td>
 181         <td>"<code>true</code>" if the current request is a subrequest,
 182             "<code>false</code>" otherwise</td></tr>
 183 <tr><td><code>THE_REQUEST</code></td>
 184         <td>The complete request line (e.g.,
 185             "<code>GET /index.html HTTP/1.1</code>")</td></tr>
 186 <tr class="odd"><td><code>REMOTE_ADDR</code></td>
 187         <td>The IP address of the remote host</td></tr>
 188 <tr><td><code>REMOTE_HOST</code></td>
 189         <td>The host name of the remote host</td></tr>
 190 <tr class="odd"><td><code>REMOTE_USER</code></td>
 191         <td>The name of the authenticated user (if any)</td></tr>
 192 <tr><td><code>REMOTE_IDENT</code></td>
 193         <td>The user name set by <code class="module"><a href="./mod/mod_ident.html">mod_ident</a></code></td></tr>
 194 <tr class="odd"><td><code>SERVER_NAME</code></td>
 195         <td>The <code class="directive"><a href="./mod/core.html#servername">ServerName</a></code> of
 196             the current vhost</td></tr>
 197 <tr><td><code>SERVER_PORT</code></td>
 198         <td>The server port of the current vhost, see
 199             <code class="directive"><a href="./mod/core.html#servername">ServerName</a></code></td></tr>
 200 <tr class="odd"><td><code>SERVER_ADMIN</code></td>
 201         <td>The <code class="directive"><a href="./mod/core.html#serveradmin">ServerAdmin</a></code> of
 202             the current vhost</td></tr>
 203 <tr><td><code>SERVER_PROTOCOL</code></td>
 204         <td>The protocol used by the request</td></tr>
 205 <tr class="odd"><td><code>DOCUMENT_ROOT</code></td>
 206         <td>The <code class="directive"><a href="./mod/core.html#documentroot">DocumentRoot</a></code> of
 207             the current vhost</td></tr>
 208 <tr><td><code>AUTH_TYPE</code></td>
 209         <td>The configured <code class="directive"><a href="./mod/mod_authn_core.html#authtype">AuthType</a></code>
 210             (e.g. "<code>basic</code>")</td></tr>
 211 <tr class="odd"><td><code>CONTENT_TYPE</code></td>
 212         <td>The content type of the response</td></tr>
 213 <tr><td><code>HANDLER</code></td>
 214         <td>The name of the <a href="handler.html">handler</a> creating
 215             the response</td></tr>
 216 <tr class="odd"><td><code>HTTPS</code></td>
 217         <td>"<code>on</code>" if the request uses https,
 218             "<code>off</code>" otherwise</td></tr>
 219 <tr><td><code>IPV6</code></td>
 220         <td>"<code>on</code>" if the connection uses IPv6,
 221             "<code>off</code>" otherwise</td></tr>
 222 <tr class="odd"><td><code>REQUEST_STATUS</code></td>
 223         <td>The HTTP error status of the request</td></tr>
 224 <tr><td><code>REQUEST_LOG_ID</code></td>
 225         <td>The error log id of the request (see
 226             <code class="directive"><a href="./mod/core.html#errorlogformat">ErrorLogFormat</a></code>)</td></tr>
 227 <tr class="odd"><td><code>CONN_LOG_ID</code></td>
 228         <td>The error log id of the connection (see
 229             <code class="directive"><a href="./mod/core.html#errorlogformat">ErrorLogFormat</a></code>)</td></tr>
 230 <tr><td><code>CONN_REMOTE_ADDR</code></td>
 231         <td>The peer IP address of the connection (see the
 232             <code class="module"><a href="./mod/mod_remoteip.html">mod_remoteip</a></code> module)</td></tr>
 233 </table>
 234
 235     <p>Misc variables</p>
 236
 237     <table class="bordered"><tr class="header"><th>Name</th><th>Description</th></tr>
 238 <tr><td><code>TIME_YEAR</code></td>
 239         <td>The current year (e.g. <code>2010</code>)</td></tr>
 240 <tr class="odd"><td><code>TIME_MON</code></td>
 241         <td>The current month (<code>1</code>, ..., <code>12</code>)</td></tr>
 242 <tr><td><code>TIME_DAY</code></td>
 243         <td>The current day of the month</td></tr>
 244 <tr class="odd"><td><code>TIME_HOUR</code></td>
 245         <td>The hour part of the current time
 246             (<code>0</code>, ..., <code>23</code>)</td></tr>
 247 <tr><td><code>TIME_MIN</code></td>
 248         <td>The minute part of the current time </td></tr>
 249 <tr class="odd"><td><code>TIME_SEC</code></td>
 250         <td>The second part of the current time </td></tr>
 251 <tr><td><code>TIME_WDAY</code></td>
 252         <td>The day of the week (starting with <code>0</code>
 253             for Sunday)</td></tr>
 254 <tr class="odd"><td><code>TIME</code></td>
 255         <td>The date and time in the format <code>20101231235959</code></td></tr>
 256 <tr><td><code>SERVER_SOFTWARE</code></td>
 257         <td>The server version string</td></tr>
 258 <tr class="odd"><td><code>API_VERSION</code></td>
 259         <td>The date of the API version (module magic number)</td></tr>
 260 </table>
 261
 262     <p>Some modules register additional variables, see e.g. <code class="module"><a href="./mod/mod_ssl.html">mod_ssl</a></code>.</p>
 263
 264 </div><div class="top"><a href="#page-header"><img alt="top" src="./images/up.gif" /></a></div>
 265 <div class="section">
 266 <h2><a name="binop" id="binop">Binary operators</a></h2>
 267
 268
 269     <p>With the exception of some built-in comparison operators, binary
 270     operators have the form "<code>-[a-zA-Z][a-zA-Z0-9_]+</code>", i.e. a
 271     minus and at least two characters. The name is not case sensitive.
 272     Modules may register additional binary operators.</p>
 273
 274     <h3><a name="comp" id="comp">Comparison operators</a></h3>
 275
 276
 277     <table class="bordered"><tr class="header"><th>Name</th><th>Alternative</th> <th>Description</th></tr>
 278 <tr><td><code>==</code></td>
 279         <td><code>=</code></td>
 280         <td>String equality</td></tr>
 281 <tr class="odd"><td><code>!=</code></td>
 282         <td />
 283         <td>String inequality</td></tr>
 284 <tr><td><code>&lt;</code></td>
 285         <td />
 286         <td>String less than</td></tr>
 287 <tr class="odd"><td><code>&lt;=</code></td>
 288         <td />
 289         <td>String less than or equal</td></tr>
 290 <tr><td><code>&gt;</code></td>
 291         <td />
 292         <td>String greater than</td></tr>
 293 <tr class="odd"><td><code>&gt;=</code></td>
 294         <td />
 295         <td>String greater than or equal</td></tr>
 296 <tr><td><code>-eq</code></td>
 297         <td><code>eq</code></td>
 298         <td>Integer equality</td></tr>
 299 <tr class="odd"><td><code>-ne</code></td>
 300         <td><code>ne</code></td>
 301         <td>Integer inequality</td></tr>
 302 <tr><td><code>-lt</code></td>
 303         <td><code>lt</code></td>
 304         <td>Integer less than</td></tr>
 305 <tr class="odd"><td><code>-le</code></td>
 306         <td><code>le</code></td>
 307         <td>Integer less than or equal</td></tr>
 308 <tr><td><code>-gt</code></td>
 309         <td><code>gt</code></td>
 310         <td>Integer greater than</td></tr>
 311 <tr class="odd"><td><code>-ge</code></td>
 312         <td><code>ge</code></td>
 313         <td>Integer greater than or equal</td></tr>
 314 </table>
 315
 316
 317     <h3><a name="binaryother" id="binaryother">Other binary operators</a></h3>
 318
 319
 320     <table class="bordered"><tr class="header"><th>Name</th><th>Description</th></tr>
 321 <tr><td><code>-ipmatch</code></td>
 322         <td>IP address matches address/netmask</td></tr>
 323 <tr class="odd"><td><code>-strmatch</code></td>
 324         <td>left string matches pattern given by right string (containing
 325             wildcards *, ?, [])</td></tr>
 326 <tr><td><code>-strcmatch</code></td>
 327         <td>same as <code>-strmatch</code>, but case insensitive</td></tr>
 328 <tr class="odd"><td><code>-fnmatch</code></td>
 329         <td>same as <code>-strmatch</code>, but slashes are not matched by
 330             wildcards</td></tr>
 331 </table>
 332
 333
 334 </div><div class="top"><a href="#page-header"><img alt="top" src="./images/up.gif" /></a></div>
 335 <div class="section">
 336 <h2><a name="unnop" id="unnop">Unary operators</a></h2>
 337
 338
 339     <p>Unary operators take one argument and have the form
 340     "<code>-[a-zA-Z]</code>", i.e. a minus and one character.
 341     The name <em>is</em> case sensitive.
 342     Modules may register additional unary operators.</p>
 343
 344     <table class="bordered"><tr class="header"><th>Name</th><th>Description</th><th>Restricted</th></tr>
 345 <tr><td><code>-d</code></td>
 346         <td>The argument is treated as a filename.
 347             True if the file exists and is a directory</td><td>yes</td></tr>
 348 <tr class="odd"><td><code>-e</code></td>
 349         <td>The argument is treated as a filename.
 350             True if the file (or dir or special) exists</td><td>yes</td></tr>
 351 <tr><td><code>-f</code></td>
 352         <td>The argument is treated as a filename.
 353             True if the file exists and is regular file</td><td>yes</td></tr>
 354 <tr class="odd"><td><code>-s</code></td>
 355         <td>The argument is treated as a filename.
 356             True if the file exists and is not empty</td><td>yes</td></tr>
 357 <tr><td><code>-L</code></td>
 358         <td>The argument is treated as a filename.
 359             True if the file exists and is symlink</td><td>yes</td></tr>
 360 <tr class="odd"><td><code>-h</code></td>
 361         <td>The argument is treated as a filename.
 362             True if the file exists and is symlink
 363             (same as <code>-L</code>)</td><td>yes</td></tr>
 364 <tr><td><code>-F</code></td>
 365         <td>True if string is a valid file, accessible via all the server's
 366             currently-configured access controls for that path. This uses an
 367             internal subrequest to do the check, so use it with care - it can
 368             impact your server's performance!</td><td /></tr>
 369 <tr class="odd"><td><code>-U</code></td>
 370         <td>True if string is a valid URL, accessible via all the server's
 371             currently-configured access controls for that path. This uses an
 372             internal subrequest to do the check, so use it with care - it can
 373             impact your server's performance!</td><td /></tr>
 374 <tr><td><code>-A</code></td>
 375         <td>Alias for <code>-U</code></td><td /></tr>
 376 <tr class="odd"><td><code>-n</code></td>
 377         <td>True if string is not empty</td><td /></tr>
 378 <tr><td><code>-z</code></td>
 379         <td>True if string is empty</td><td /></tr>
 380 <tr class="odd"><td><code>-T</code></td>
 381         <td>False if string is empty, "<code>0</code>", "<code>off</code>",
 382             "<code>false</code>", or "<code>no</code>" (case insensitive).
 383             True otherwise.</td><td /></tr>
 384 <tr><td><code>-R</code></td>
 385         <td>Same as "<code>%{REMOTE_ADDR} -ipmatch ...</code>", but more efficient
 386         </td><td /></tr>
 387 </table>
 388
 389     <p>The operators marked as "restricted" are not available in some modules
 390     like <code class="module"><a href="./mod/mod_include.html">mod_include</a></code>.</p>
 391 </div><div class="top"><a href="#page-header"><img alt="top" src="./images/up.gif" /></a></div>
 392 <div class="section">
 393 <h2><a name="functions" id="functions">Functions</a></h2>
 394
 395
 396     <p>Normal string-valued functions take one string as argument and return
 397     a string. Functions names are not case sensitive.
 398     Modules may register additional functions.</p>
 399
 400     <table class="bordered"><tr class="header"><th>Name</th><th>Description</th><th>Restricted</th></tr>
 401 <tr><td><code>req</code>, <code>http</code></td>
 402         <td>Get HTTP request header</td><td /></tr>
 403 <tr class="odd"><td><code>resp</code></td>
 404         <td>Get HTTP response header</td><td /></tr>
 405 <tr><td><code>reqenv</code></td>
 406         <td>Lookup request environment variable</td><td /></tr>
 407 <tr class="odd"><td><code>osenv</code></td>
 408         <td>Lookup operating system environment variable</td><td /></tr>
 409 <tr><td><code>note</code></td>
 410         <td>Lookup request note</td><td /></tr>
 411 <tr class="odd"><td><code>env</code></td>
 412         <td>Return first match of <code>note</code>, <code>reqenv</code>,
 413             <code>osenv</code></td><td /></tr>
 414 <tr><td><code>tolower</code></td>
 415         <td>Convert string to lower case</td><td /></tr>
 416 <tr class="odd"><td><code>toupper</code></td>
 417         <td>Convert string to uppser case</td><td /></tr>
 418 <tr><td><code>escape</code></td>
 419         <td>Escape special characters in %hex encoding</td><td /></tr>
 420 <tr class="odd"><td><code>unescape</code></td>
 421         <td>Unescape %hex encoded string, leaving encoded slashes alone;
 422             return empty string if %00 is found</td><td /></tr>
 423 <tr><td><code>file</code></td>
 424         <td>Read contents from a file</td><td>yes</td></tr>
 425 <tr class="odd"><td><code>filesize</code></td>
 426         <td>Return size of a file (or 0 if file does not exist or is not
 427             regular file)</td><td>yes</td></tr>
 428 </table>
 429
 430     <p>The functions marked as "restricted" are not available in some modules
 431     like <code class="module"><a href="./mod/mod_include.html">mod_include</a></code>.</p>
 432
 433     <p>In addition to string-valued functions, there are also list-valued functions which
 434     take one string as argument and return a wordlist, i.e. a list of strings. The wordlist
 435     can be used with the special <code>-in</code> operator.
 436     Functions names are not case sensitive.
 437     Modules may register additional functions.</p>
 438
 439     <p>There are no built-in list-valued functions. <code class="module"><a href="./mod/mod_ssl.html">mod_ssl</a></code>
 440     provides <code>PeerExtList</code>.  See the description of
 441     <code class="directive"><a href="./mod/mod_ssl.html#sslrequire">SSLRequire</a></code> for details
 442     (but <code>PeerExtList</code> is also usable outside
 443     of <code class="directive"><a href="./mod/mod_ssl.html#sslrequire">SSLRequire</a></code>).</p>
 444
 445 </div><div class="top"><a href="#page-header"><img alt="top" src="./images/up.gif" /></a></div>
 446 <div class="section">
 447 <h2><a name="examples" id="examples">Example expressions</a></h2>
 448
 449
 450         <p>The following examples show how expressions might be used to evaluate requests:</p>
 451
 452         <div class="example"><p><code>
 453         # Compare the host name to example.com and redirect to www.example.com if it matches<br />
 454         &lt;If "%{HTTP_HOST} == 'example.com'"&gt;<br />
 455         <span class="indent">
 456                 Redirect permanent / http://www.example.com<br />
 457         </span>
 458         &lt;/If&gt;<br /><br />
 459         # Force text/plain if requesting a file with the query string contains 'forcetext'<br />
 460         &lt;If "%{QUERY_STRING} =~ /forcetext/"&gt;<br />
 461         <span class="indent">
 462                 ForceType text/plain<br />
 463         </span>
 464         &lt;/If&gt;<br /><br />
 465         # Only allow access to this content during business hours<br />
 466         &lt;Directory "/foo/bar/business"&gt;<br />
 467         <span class="indent">
 468                 Require expr %{TIME_HOUR} &gt;= 9 &amp;&amp; %{TIME_HOUR} &lt;= 17 <br />
 469         </span>
 470         &lt;/Directory&gt;
 471         </code></p></div>
 472 </div><div class="top"><a href="#page-header"><img alt="top" src="./images/up.gif" /></a></div>
 473 <div class="section">
 474 <h2><a name="other" id="other">Other</a></h2>
 475
 476
 477     <table class="bordered"><tr class="header"><th>Name</th><th>Alternative</th> <th>Description</th></tr>
 478 <tr><td><code>-in</code></td>
 479         <td><code>in</code></td>
 480         <td>string contained in string list</td></tr>
 481 <tr class="odd"><td><code>/regexp/</code></td>
 482         <td><code>m#regexp#</code></td>
 483         <td>Regular expression (the second form allows different delimiters than /)</td></tr>
 484 <tr><td><code>/regexp/i</code></td>
 485         <td><code>m#regexp#i</code></td>
 486         <td>Case insensitive regular expression</td></tr>
 487 <tr class="odd"><td><code>$0 ... $9</code></td>
 488         <td />
 489         <td>Regular expression backreferences</td></tr>
 490 </table>
 491
 492     <h3><a name="rebackref" id="rebackref">Regular expression backreferences</a></h3>
 493
 494         <p>The strings <code>$0</code> ... <code>$9</code> allow to reference
 495         the capture groups from a previously executed, successfully
 496         matching regular expressions. They can normally only be used in the
 497         same expression as the matching regex, but some modules allow special
 498         uses.</p>
 499
 500
 501 </div><div class="top"><a href="#page-header"><img alt="top" src="./images/up.gif" /></a></div>
 502 <div class="section">
 503 <h2><a name="sslrequire" id="sslrequire">Comparison with SSLRequire</a></h2>
 504
 505     <p>The <em>ap_expr</em> syntax is mostly a superset of the syntax of the
 506     deprecated <code class="directive"><a href="./mod/mod_ssl.html#sslrequire">SSLRequire</a></code> directive.
 507     The differences are described in <code class="directive"><a href="./mod/mod_ssl.html#sslrequire">SSLRequire</a></code>'s documentation.</p>
 508 </div></div>
 509 <div class="bottomlang">
 510 <p><span>Available Languages: </span><a href="./en/expr.html" title="English">&nbsp;en&nbsp;</a> |
 511 <a href="./fr/expr.html" hreflang="fr" rel="alternate" title="Français">&nbsp;fr&nbsp;</a></p>
 512 </div><div id="footer">
 513 <p class="apache">Copyright 2012 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>
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