expr.html.en 35.5 KB
Newer Older
powelld's avatar
powelld committed
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522 523 524 525 526 527 528 529 530 531 532 533 534 535 536 537 538 539 540 541 542 543 544 545 546 547 548 549 550 551 552 553 554 555 556 557 558 559 560 561 562 563 564 565 566 567 568 569 570 571 572 573 574 575 576 577 578 579 580 581 582 583 584 585 586 587 588 589 590 591 592 593 594 595 596 597 598 599 600 601 602 603 604 605 606 607 608 609 610 611 612 613 614 615 616 617 618 619 620 621 622 623 624 625 626 627 628 629 630 631 632 633 634 635 636 637 638 639 640 641 642 643 644 645 646 647 648 649 650
<?xml version="1.0" encoding="ISO-8859-1"?>
<!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=ISO-8859-1" 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="&lt;-" alt="&lt;-" src="./images/left.gif" /></a></div>
<div id="path">
<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 2.4</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">&nbsp;en&nbsp;</a> |
<a href="./fr/expr.html" hreflang="fr" rel="alternate" title="Franais">&nbsp;fr&nbsp;</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">&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/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_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>&amp;&amp;</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>&lt;</strong>"  word
              | word "<strong>&lt;=</strong>" word
              | word "<strong>&gt;</strong>"  word
              | word "<strong>&gt;=</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">&lt;If &gt;</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">&lt;If &gt;</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">&lt;If &gt;</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">&lt;If &gt;</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>&lt;</code></td>
        <td />
        <td>String less than</td></tr>
<tr class="odd"><td><code>&lt;=</code></td>
        <td />
        <td>String less than or equal</td></tr>
<tr><td><code>&gt;</code></td>
        <td />
        <td>String greater than</td></tr>
<tr class="odd"><td><code>&gt;=</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</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>filemod</code></td>
        <td>Return last modification time 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>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>
</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 
    &lt;<code class="directive"><a href="./mod/core.html#if">If</a></code>&gt; directive which is
    evaluated relatively early.</p>
    <div class="note">
    <h3>Environment variable ordering</h3>
    When environment variables are looked up within an 
    &lt;<code class="directive"><a href="./mod/core.html#if">If</a></code>&gt; 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 &lt;<code class="directive"><a href="./mod/core.html#if">If</a></code>&gt;, 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
&lt;If "%{HTTP_HOST} == 'example.com'"&gt;
    Redirect permanent "/" "http://www.example.com/"
&lt;/If&gt;

# Force text/plain if requesting a file with the query string contains 'forcetext'
&lt;If "%{QUERY_STRING} =~ /forcetext/"&gt;
    ForceType text/plain
&lt;/If&gt;

# Only allow access to this content during business hours
&lt;Directory "/foo/bar/business"&gt;
    Require expr %{TIME_HOUR} -gt 9 &amp;&amp; %{TIME_HOUR} -lt 17
&lt;/Directory&gt;

# Check a HTTP header for a list of values
&lt;If "%{HTTP:X-example-header} in { 'foo', 'bar', 'baz' }"&gt;
    Header set matched true
&lt;/If&gt;

# Check an environment variable for a regular expression, negated.
&lt;If "! reqenv('REDIRECT_FOO') =~ /bar/"&gt;
    Header set matched true
&lt;/If&gt;

# Check result of URI mapping by running in Directory context with -f
&lt;Directory "/var/www"&gt;
    AddEncoding x-gzip gz
&lt;If "-f '%{REQUEST_FILENAME}.unzipme' &amp;&amp; ! %{HTTP:Accept-Encoding} =~ /gzip/"&gt;
      SetOutputFilter INFLATE
&lt;/If&gt;
&lt;/Directory&gt;

# Check against the client IP
&lt;If "-R '192.168.1.0/24'"&gt;
    Header set matched true
&lt;/If&gt;

# Function example in boolean context
&lt;If "md5('foo') == 'acbd18db4cc2f85cedef654fccc4a4d8'"&gt;
  Header set checksum-matched true
&lt;/If&gt;

# Function example in string context
Header set foo-checksum "expr=%{md5:foo}"

# This delays the evaluation of the condition clause compared to &lt;If&gt;
Header always set CustomHeader my-value "expr=%{REQUEST_URI} =~ m#^/special_path\.php$#"</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">&nbsp;en&nbsp;</a> |
<a href="./fr/expr.html" hreflang="fr" rel="alternate" title="Franais">&nbsp;fr&nbsp;</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&amp;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>
<script type="text/javascript"><!--//--><![CDATA[//><!--
var comments_shortname = 'httpd';
var comments_identifier = 'http://httpd.apache.org/docs/2.4/expr.html';
(function(w, d) {
    if (w.location.hostname.toLowerCase() == "httpd.apache.org") {
        d.write('<div id="comments_thread"><\/div>');
        var s = d.createElement('script');
        s.type = 'text/javascript';
        s.async = true;
        s.src = 'https://comments.apache.org/show_comments.lua?site=' + comments_shortname + '&page=' + comments_identifier;
        (d.getElementsByTagName('head')[0] || d.getElementsByTagName('body')[0]).appendChild(s);
    }
    else { 
        d.write('<div id="comments_thread">Comments are disabled for this page at the moment.<\/div>');
    }
})(window, document);
//--><!]]></script></div><div id="footer">
<p class="apache">Copyright 2017 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>
<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></div><script type="text/javascript"><!--//--><![CDATA[//><!--
if (typeof(prettyPrint) !== 'undefined') {
    prettyPrint();
}
//--><!]]></script>
</body></html>