d0978b1d74a5614cfc225aa772fe90344bf85d0drbowen<?xml version="1.0" encoding="UTF-8"?>

0a3142725875ea286597e083547d34d98f8c1f2drbowen<!DOCTYPE manualpage SYSTEM "/style/manualpage.dtd">

0a3142725875ea286597e083547d34d98f8c1f2drbowen<?xml-stylesheet type="text/xsl" href="/style/manual.en.xsl"?>

0a3142725875ea286597e083547d34d98f8c1f2drbowen<manualpage metafile="rewritemap.xml.meta">

0a3142725875ea286597e083547d34d98f8c1f2drbowen <parentdocument href="./">Rewrite</parentdocument>

d0978b1d74a5614cfc225aa772fe90344bf85d0drbowen <title>Using RewriteMap</title>

d0978b1d74a5614cfc225aa772fe90344bf85d0drbowen <summary>

83f3471f5de14ca3def6d7935cd1af1604874bfdrbowen <p>This document supplements the <module>mod_rewrite</module>

d0978b1d74a5614cfc225aa772fe90344bf85d0drbowen<a href="/mod/mod_rewrite.html">reference documentation</a>. It describes

0a3142725875ea286597e083547d34d98f8c1f2drbowenthe use of the <directive module="mod_rewrite">RewriteMap</directive> directive,

0a3142725875ea286597e083547d34d98f8c1f2drbowenand provides examples of each of the various <code>RewriteMap</code> types.</p>

0a3142725875ea286597e083547d34d98f8c1f2drbowen <note type="warning">Note that many of these examples won't work unchanged in your

83f3471f5de14ca3def6d7935cd1af1604874bfdrbowenparticular server configuration, so it's important that you understand

d0978b1d74a5614cfc225aa772fe90344bf85d0drbowenthem, rather than merely cutting and pasting the examples into your

0a3142725875ea286597e083547d34d98f8c1f2drbowenconfiguration.</note>

0a3142725875ea286597e083547d34d98f8c1f2drbowen </summary>

0a3142725875ea286597e083547d34d98f8c1f2drbowen <seealso> <a href="/mod/mod_rewrite.html">Module documentation</a> </seealso>

83f3471f5de14ca3def6d7935cd1af1604874bfdrbowen <seealso> <a href="intro.html">mod_rewrite introduction</a> </seealso>

d0978b1d74a5614cfc225aa772fe90344bf85d0drbowen <seealso> <a href="remapping.html">Redirection and remapping</a> </seealso>

83f3471f5de14ca3def6d7935cd1af1604874bfdrbowen <seealso> <a href="access.html">Controlling access</a> </seealso>

83f3471f5de14ca3def6d7935cd1af1604874bfdrbowen <seealso> <a href="vhosts.html">Virtual hosts</a> </seealso>

83f3471f5de14ca3def6d7935cd1af1604874bfdrbowen <seealso> <a href="proxy.html">Proxying</a> </seealso>

83f3471f5de14ca3def6d7935cd1af1604874bfdrbowen <seealso> <a href="advanced.html">Advanced techniques and tricks</a> </seealso>

83f3471f5de14ca3def6d7935cd1af1604874bfdrbowen <seealso> <a href="avoid.html">When not to use mod_rewrite</a> </seealso>

83f3471f5de14ca3def6d7935cd1af1604874bfdrbowen

83f3471f5de14ca3def6d7935cd1af1604874bfdrbowen <section id="introduction">

83f3471f5de14ca3def6d7935cd1af1604874bfdrbowen <title>Introduction</title>

365711300b7310a1efed8aa9f01492086882ba7crbowen <p>The <directive>RewriteMap</directive> directive defines a

d0978b1d74a5614cfc225aa772fe90344bf85d0drbowen <em>Rewriting Map</em> which can be used inside rule

d0978b1d74a5614cfc225aa772fe90344bf85d0drbowen substitution strings by the mapping-functions to

83f3471f5de14ca3def6d7935cd1af1604874bfdrbowen insert/substitute fields through a key lookup. The source of

83f3471f5de14ca3def6d7935cd1af1604874bfdrbowen this lookup can be of various types.</p>

83f3471f5de14ca3def6d7935cd1af1604874bfdrbowen <p>The <a id="mapfunc" name="mapfunc"><em>MapName</em></a> is

83f3471f5de14ca3def6d7935cd1af1604874bfdrbowen the name of the map and will be used to specify a

83f3471f5de14ca3def6d7935cd1af1604874bfdrbowen mapping-function for the substitution strings of a rewriting

83f3471f5de14ca3def6d7935cd1af1604874bfdrbowen rule via one of the following constructs:</p>

83f3471f5de14ca3def6d7935cd1af1604874bfdrbowen <p class="indent">

83f3471f5de14ca3def6d7935cd1af1604874bfdrbowen <strong>

83f3471f5de14ca3def6d7935cd1af1604874bfdrbowen <code>${</code>

83f3471f5de14ca3def6d7935cd1af1604874bfdrbowen <em>MapName</em>

83f3471f5de14ca3def6d7935cd1af1604874bfdrbowen <code>:</code>

83f3471f5de14ca3def6d7935cd1af1604874bfdrbowen <em>LookupKey</em>

83f3471f5de14ca3def6d7935cd1af1604874bfdrbowen <code>}</code>

83f3471f5de14ca3def6d7935cd1af1604874bfdrbowen <br/>

83f3471f5de14ca3def6d7935cd1af1604874bfdrbowen <code>${</code>

83f3471f5de14ca3def6d7935cd1af1604874bfdrbowen <em>MapName</em>

83f3471f5de14ca3def6d7935cd1af1604874bfdrbowen <code>:</code>

83f3471f5de14ca3def6d7935cd1af1604874bfdrbowen <em>LookupKey</em>

83f3471f5de14ca3def6d7935cd1af1604874bfdrbowen <code>|</code>

83f3471f5de14ca3def6d7935cd1af1604874bfdrbowen <em>DefaultValue</em>

83f3471f5de14ca3def6d7935cd1af1604874bfdrbowen <code>}</code>

83f3471f5de14ca3def6d7935cd1af1604874bfdrbowen </strong>

83f3471f5de14ca3def6d7935cd1af1604874bfdrbowen </p>

83f3471f5de14ca3def6d7935cd1af1604874bfdrbowen <p>When such a construct occurs, the map <em>MapName</em> is

d0978b1d74a5614cfc225aa772fe90344bf85d0drbowen consulted and the key <em>LookupKey</em> is looked-up. If the

d0978b1d74a5614cfc225aa772fe90344bf85d0drbowen key is found, the map-function construct is substituted by

83f3471f5de14ca3def6d7935cd1af1604874bfdrbowen <em>SubstValue</em>. If the key is not found then it is

83f3471f5de14ca3def6d7935cd1af1604874bfdrbowen substituted by <em>DefaultValue</em> or by the empty string

83f3471f5de14ca3def6d7935cd1af1604874bfdrbowen if no <em>DefaultValue</em> was specified.</p>

d0978b1d74a5614cfc225aa772fe90344bf85d0drbowen <p>For example, you might define a

d0978b1d74a5614cfc225aa772fe90344bf85d0drbowen <directive>RewriteMap</directive> as:</p>

83f3471f5de14ca3def6d7935cd1af1604874bfdrbowen <example>

d0978b1d74a5614cfc225aa772fe90344bf85d0drbowen RewriteMap examplemap txt:/path/to/file/map.txt

0a3142725875ea286597e083547d34d98f8c1f2drbowen </example>

0a3142725875ea286597e083547d34d98f8c1f2drbowen <p>You would then be able to use this map in a

0a3142725875ea286597e083547d34d98f8c1f2drbowen <directive>RewriteRule</directive> as follows:</p>

0a3142725875ea286597e083547d34d98f8c1f2drbowen <example>

0a3142725875ea286597e083547d34d98f8c1f2drbowen RewriteRule ^/ex/(.*) ${examplemap:$1}

83f3471f5de14ca3def6d7935cd1af1604874bfdrbowen </example>

d0978b1d74a5614cfc225aa772fe90344bf85d0drbowen <p>The following combinations for <em>MapType</em> and

0a3142725875ea286597e083547d34d98f8c1f2drbowen <em>MapSource</em> can be used:</p>

d0978b1d74a5614cfc225aa772fe90344bf85d0drbowen </section>

0a3142725875ea286597e083547d34d98f8c1f2drbowen <section id="txt">

0a3142725875ea286597e083547d34d98f8c1f2drbowen <title>txt: Plain text maps</title>

d0978b1d74a5614cfc225aa772fe90344bf85d0drbowen <p>MapType: <code>txt</code>, MapSource: Unix filesystem

0a3142725875ea286597e083547d34d98f8c1f2drbowen path to valid regular file</p>

721755eb7ca9b3bf233f223d48e43edd7795c6ebrbowen <p>This is the standard rewriting map feature where the

721755eb7ca9b3bf233f223d48e43edd7795c6ebrbowen <em>MapSource</em> is a plain ASCII file containing

721755eb7ca9b3bf233f223d48e43edd7795c6ebrbowen either blank lines, comment lines (starting with a '#'

721755eb7ca9b3bf233f223d48e43edd7795c6ebrbowen character) or pairs like the following - one per

721755eb7ca9b3bf233f223d48e43edd7795c6ebrbowen line.</p>

721755eb7ca9b3bf233f223d48e43edd7795c6ebrbowen <p class="indent">

721755eb7ca9b3bf233f223d48e43edd7795c6ebrbowen <strong>

721755eb7ca9b3bf233f223d48e43edd7795c6ebrbowen <em>MatchingKey</em>

721755eb7ca9b3bf233f223d48e43edd7795c6ebrbowen <em>SubstValue</em>

721755eb7ca9b3bf233f223d48e43edd7795c6ebrbowen </strong>

83f3471f5de14ca3def6d7935cd1af1604874bfdrbowen </p>

83f3471f5de14ca3def6d7935cd1af1604874bfdrbowen <example>

83f3471f5de14ca3def6d7935cd1af1604874bfdrbowen <title>Example</title>

0a3142725875ea286597e083547d34d98f8c1f2drbowen <pre>

83f3471f5de14ca3def6d7935cd1af1604874bfdrbowen##

d0978b1d74a5614cfc225aa772fe90344bf85d0drbowen## map.txt -- rewriting map

d0978b1d74a5614cfc225aa772fe90344bf85d0drbowen##

721755eb7ca9b3bf233f223d48e43edd7795c6ebrbowen

721755eb7ca9b3bf233f223d48e43edd7795c6ebrbowenRalf.S.Engelschall rse # Bastard Operator From Hell

721755eb7ca9b3bf233f223d48e43edd7795c6ebrbowenMr.Joe.Average joe # Mr. Average

721755eb7ca9b3bf233f223d48e43edd7795c6ebrbowen</pre>

721755eb7ca9b3bf233f223d48e43edd7795c6ebrbowen </example>

721755eb7ca9b3bf233f223d48e43edd7795c6ebrbowen <example>

721755eb7ca9b3bf233f223d48e43edd7795c6ebrbowenRewriteMap real-to-user txt:/path/to/file/map.txt

721755eb7ca9b3bf233f223d48e43edd7795c6ebrbowen</example>

721755eb7ca9b3bf233f223d48e43edd7795c6ebrbowen </section>

d0978b1d74a5614cfc225aa772fe90344bf85d0drbowen <section id="rnd">

721755eb7ca9b3bf233f223d48e43edd7795c6ebrbowen <title>rnd: Randomized Plain Text</title>

721755eb7ca9b3bf233f223d48e43edd7795c6ebrbowen <p>MapType: <code>rnd</code>, MapSource: Unix filesystem

721755eb7ca9b3bf233f223d48e43edd7795c6ebrbowen path to valid regular file</p>

d0978b1d74a5614cfc225aa772fe90344bf85d0drbowen <p>This is identical to the Standard Plain Text variant

721755eb7ca9b3bf233f223d48e43edd7795c6ebrbowen above but with a special post-processing feature: After

721755eb7ca9b3bf233f223d48e43edd7795c6ebrbowen looking up a value it is parsed according to contained

721755eb7ca9b3bf233f223d48e43edd7795c6ebrbowen ``<code>|</code>'' characters which have the meaning of

721755eb7ca9b3bf233f223d48e43edd7795c6ebrbowen ``or''. In other words they indicate a set of

721755eb7ca9b3bf233f223d48e43edd7795c6ebrbowen alternatives from which the actual returned value is

721755eb7ca9b3bf233f223d48e43edd7795c6ebrbowen chosen randomly. For example, you might use the following map

721755eb7ca9b3bf233f223d48e43edd7795c6ebrbowen file and directives to provide a random load balancing between

721755eb7ca9b3bf233f223d48e43edd7795c6ebrbowen several back-end server, via a reverse-proxy. Images are sent

721755eb7ca9b3bf233f223d48e43edd7795c6ebrbowen to one of the servers in the 'static' pool, while everything

721755eb7ca9b3bf233f223d48e43edd7795c6ebrbowen else is sent to one of the 'dynamic' pool.</p>

721755eb7ca9b3bf233f223d48e43edd7795c6ebrbowen <p>Example:</p>

721755eb7ca9b3bf233f223d48e43edd7795c6ebrbowen <example>

721755eb7ca9b3bf233f223d48e43edd7795c6ebrbowen <title>Rewrite map file</title>

721755eb7ca9b3bf233f223d48e43edd7795c6ebrbowen <pre>

721755eb7ca9b3bf233f223d48e43edd7795c6ebrbowen##

721755eb7ca9b3bf233f223d48e43edd7795c6ebrbowen## map.txt -- rewriting map

721755eb7ca9b3bf233f223d48e43edd7795c6ebrbowen##

721755eb7ca9b3bf233f223d48e43edd7795c6ebrbowen

721755eb7ca9b3bf233f223d48e43edd7795c6ebrbowenstatic www1|www2|www3|www4

721755eb7ca9b3bf233f223d48e43edd7795c6ebrbowendynamic www5|www6

721755eb7ca9b3bf233f223d48e43edd7795c6ebrbowen</pre>

721755eb7ca9b3bf233f223d48e43edd7795c6ebrbowen </example>

d0978b1d74a5614cfc225aa772fe90344bf85d0drbowen <example><title>Configuration directives</title>

0a3142725875ea286597e083547d34d98f8c1f2drbowenRewriteMap servers rnd:/path/to/file/map.txt<br/>

721755eb7ca9b3bf233f223d48e43edd7795c6ebrbowen<br/>

0a3142725875ea286597e083547d34d98f8c1f2drbowenRewriteRule ^/(.*\.(png|gif|jpg)) http://${servers:static}/$1

0a3142725875ea286597e083547d34d98f8c1f2drbowen[NC,P,L]<br/>

721755eb7ca9b3bf233f223d48e43edd7795c6ebrbowenRewriteRule ^/(.*) http://${servers:dynamic}/$1 [P,L]

721755eb7ca9b3bf233f223d48e43edd7795c6ebrbowen</example>

721755eb7ca9b3bf233f223d48e43edd7795c6ebrbowen </section>

721755eb7ca9b3bf233f223d48e43edd7795c6ebrbowen <section id="dbm">

721755eb7ca9b3bf233f223d48e43edd7795c6ebrbowen <title>dbm: DBM Hash File</title>

0a3142725875ea286597e083547d34d98f8c1f2drbowen <p>MapType:

d0978b1d74a5614cfc225aa772fe90344bf85d0drbowen <code>dbm[=<em>type</em>]</code>, MapSource: Unix filesystem

721755eb7ca9b3bf233f223d48e43edd7795c6ebrbowen path to valid regular file</p>

721755eb7ca9b3bf233f223d48e43edd7795c6ebrbowen <p>Here the source is a binary format DBM file containing

721755eb7ca9b3bf233f223d48e43edd7795c6ebrbowen the same contents as a <em>Plain Text</em> format file, but

721755eb7ca9b3bf233f223d48e43edd7795c6ebrbowen in a special representation which is optimized for really

721755eb7ca9b3bf233f223d48e43edd7795c6ebrbowen fast lookups. The <em>type</em> can be sdbm, gdbm, ndbm, or

721755eb7ca9b3bf233f223d48e43edd7795c6ebrbowen db depending on <a href="/install.html#dbm">compile-time

721755eb7ca9b3bf233f223d48e43edd7795c6ebrbowen settings</a>. If the <em>type</em> is omitted, the

721755eb7ca9b3bf233f223d48e43edd7795c6ebrbowen compile-time default will be chosen.</p>

721755eb7ca9b3bf233f223d48e43edd7795c6ebrbowen <p>To create a dbm file from a source text file, use the <a href="/programs/httxt2dbm.html">httxt2dbm</a> utility.</p>

721755eb7ca9b3bf233f223d48e43edd7795c6ebrbowen <example>

d0978b1d74a5614cfc225aa772fe90344bf85d0drbowen$ httxt2dbm -i mapfile.txt -o mapfile.map

721755eb7ca9b3bf233f223d48e43edd7795c6ebrbowen</example>

721755eb7ca9b3bf233f223d48e43edd7795c6ebrbowen </section>

721755eb7ca9b3bf233f223d48e43edd7795c6ebrbowen <section id="int">

721755eb7ca9b3bf233f223d48e43edd7795c6ebrbowen <title>int: Internal Function</title>

d0978b1d74a5614cfc225aa772fe90344bf85d0drbowen <p>

d0978b1d74a5614cfc225aa772fe90344bf85d0drbowen MapType: <code>int</code>, MapSource: Internal Apache httpd

d0978b1d74a5614cfc225aa772fe90344bf85d0drbowen function</p>

d0978b1d74a5614cfc225aa772fe90344bf85d0drbowen <p>Here, the source is an internal Apache httpd function.

0a3142725875ea286597e083547d34d98f8c1f2drbowen Currently you cannot create your own, but the following

d0978b1d74a5614cfc225aa772fe90344bf85d0drbowen functions already exist:</p>

0a3142725875ea286597e083547d34d98f8c1f2drbowen <ul>

0a3142725875ea286597e083547d34d98f8c1f2drbowen <li><strong>toupper</strong>:<br/>

0a3142725875ea286597e083547d34d98f8c1f2drbowen Converts the key to all upper case.</li>

0a3142725875ea286597e083547d34d98f8c1f2drbowen <li><strong>tolower</strong>:<br/>

0a3142725875ea286597e083547d34d98f8c1f2drbowen Converts the key to all lower case.</li>

0a3142725875ea286597e083547d34d98f8c1f2drbowen <li><strong>escape</strong>:<br/>

0a3142725875ea286597e083547d34d98f8c1f2drbowen Translates special characters in the key to

0a3142725875ea286597e083547d34d98f8c1f2drbowen hex-encodings.</li>

0a3142725875ea286597e083547d34d98f8c1f2drbowen <li><strong>unescape</strong>:<br/>

0a3142725875ea286597e083547d34d98f8c1f2drbowen Translates hex-encodings in the key back to

d0978b1d74a5614cfc225aa772fe90344bf85d0drbowen special characters.</li>

d0978b1d74a5614cfc225aa772fe90344bf85d0drbowen </ul>

d0978b1d74a5614cfc225aa772fe90344bf85d0drbowen </section>

d0978b1d74a5614cfc225aa772fe90344bf85d0drbowen <section id="prg"><title>prg: External Rewriting Program</title><p>

0a3142725875ea286597e083547d34d98f8c1f2drbowen MapType: <code>prg</code>, MapSource: Unix filesystem

0a3142725875ea286597e083547d34d98f8c1f2drbowen path to valid regular file

0a3142725875ea286597e083547d34d98f8c1f2drbowen </p><p>Here the source is a program, not a map file. To

0a3142725875ea286597e083547d34d98f8c1f2drbowen create it you can use a language of your choice, but

0a3142725875ea286597e083547d34d98f8c1f2drbowen the result has to be an executable program (either

0a3142725875ea286597e083547d34d98f8c1f2drbowen object-code or a script with the magic cookie trick

0a3142725875ea286597e083547d34d98f8c1f2drbowen '<code>#!/path/to/interpreter</code>' as the first

d0978b1d74a5614cfc225aa772fe90344bf85d0drbowen line).</p><p>This program is started once, when the Apache httpd server

d0978b1d74a5614cfc225aa772fe90344bf85d0drbowen is started, and then communicates with the rewriting engine

d0978b1d74a5614cfc225aa772fe90344bf85d0drbowen via its <code>stdin</code> and <code>stdout</code>

d0978b1d74a5614cfc225aa772fe90344bf85d0drbowen file-handles. For each map-function lookup it will

0a3142725875ea286597e083547d34d98f8c1f2drbowen receive the key to lookup as a newline-terminated string

d0978b1d74a5614cfc225aa772fe90344bf85d0drbowen on <code>stdin</code>. It then has to give back the

0a3142725875ea286597e083547d34d98f8c1f2drbowen looked-up value as a newline-terminated string on

0a3142725875ea286597e083547d34d98f8c1f2drbowen <code>stdout</code> or the four-character string

d0978b1d74a5614cfc225aa772fe90344bf85d0drbowen ``<code>NULL</code>'' if it fails (<em>i.e.</em>, there

d0978b1d74a5614cfc225aa772fe90344bf85d0drbowen is no corresponding value for the given key).</p><p>This feature utilizes the <code>rewrite-map</code> mutex,

d0978b1d74a5614cfc225aa772fe90344bf85d0drbowen which is required for reliable communication with the program.

d0978b1d74a5614cfc225aa772fe90344bf85d0drbowen The mutex mechanism and lock file can be configured with the

0a3142725875ea286597e083547d34d98f8c1f2drbowen <directive module="core">Mutex</directive> directive.</p><p>External rewriting programs are not started if they're defined in a

0a3142725875ea286597e083547d34d98f8c1f2drbowen context that does not have <directive>RewriteEngine</directive> set to

d0978b1d74a5614cfc225aa772fe90344bf85d0drbowen <code>on</code></p>.

0a3142725875ea286597e083547d34d98f8c1f2drbowen

0a3142725875ea286597e083547d34d98f8c1f2drbowen <p>A trivial program which will implement a 1:1 map (<em>i.e.</em>,

0a3142725875ea286597e083547d34d98f8c1f2drbowen key == value) could be:</p><example><pre>

0a3142725875ea286597e083547d34d98f8c1f2drbowen#!/usr/bin/perl

0a3142725875ea286597e083547d34d98f8c1f2drbowen$| = 1;

0a3142725875ea286597e083547d34d98f8c1f2drbowenwhile (&lt;STDIN&gt;) {

d0978b1d74a5614cfc225aa772fe90344bf85d0drbowen # ...put here any transformations or lookups...

d0978b1d74a5614cfc225aa772fe90344bf85d0drbowen print $_;

0a3142725875ea286597e083547d34d98f8c1f2drbowen}

0a3142725875ea286597e083547d34d98f8c1f2drbowen</pre></example><p>But be very careful:</p><ol><li>``<em>Keep it simple, stupid</em>'' (KISS).

d0978b1d74a5614cfc225aa772fe90344bf85d0drbowenIf this program hangs, it will cause Apache httpd to hang

d0978b1d74a5614cfc225aa772fe90344bf85d0drbowenwhen trying to use the relevant rewrite rule.</li><li>A common mistake is to use buffered I/O on

d0978b1d74a5614cfc225aa772fe90344bf85d0drbowen<code>stdout</code>. Avoid this, as it will cause a deadloop!

d0978b1d74a5614cfc225aa772fe90344bf85d0drbowen``<code>$|=1</code>'' is used above, to prevent this.</li></ol></section>

0a3142725875ea286597e083547d34d98f8c1f2drbowen <section id="dbd">

0a3142725875ea286597e083547d34d98f8c1f2drbowen <title>dbd or fastdbd: SQL Query</title>

d0978b1d74a5614cfc225aa772fe90344bf85d0drbowen <p>MapType: <code>dbd</code> or <code>fastdbd</code>,

0a3142725875ea286597e083547d34d98f8c1f2drbowenMapSource: An SQL SELECT statement that takes a single

0a3142725875ea286597e083547d34d98f8c1f2drbowen argument and returns a single value.</p>

d0978b1d74a5614cfc225aa772fe90344bf85d0drbowen <p>This uses <module>mod_dbd</module> to implement a rewritemap

d0978b1d74a5614cfc225aa772fe90344bf85d0drbowenby lookup in an SQL database. There are two forms:

0a3142725875ea286597e083547d34d98f8c1f2drbowen<code>fastdbd</code> caches database lookups internally,

d0978b1d74a5614cfc225aa772fe90344bf85d0drbowen<code>dbd</code> doesn't. So <code>dbd</code> incurs a

0a3142725875ea286597e083547d34d98f8c1f2drbowenperformance penalty but responds immediately if the database

d0978b1d74a5614cfc225aa772fe90344bf85d0drbowencontents are updated, while <code>fastdbd</code> is more

0a3142725875ea286597e083547d34d98f8c1f2drbowenefficient but won't re-read database contents until server

0a3142725875ea286597e083547d34d98f8c1f2drbowenrestart.</p>

d0978b1d74a5614cfc225aa772fe90344bf85d0drbowen <p>If a query returns more than one row, a random row from

0a3142725875ea286597e083547d34d98f8c1f2drbowenthe result set is used.</p>

0a3142725875ea286597e083547d34d98f8c1f2drbowen <example><title>Example</title>

d0978b1d74a5614cfc225aa772fe90344bf85d0drbowenRewriteMap myquery "fastdbd:SELECT destination FROM rewrite WHERE source = %s"

d0978b1d74a5614cfc225aa772fe90344bf85d0drbowen</example>

83f3471f5de14ca3def6d7935cd1af1604874bfdrbowen </section>

83f3471f5de14ca3def6d7935cd1af1604874bfdrbowen <section id="summary">

83f3471f5de14ca3def6d7935cd1af1604874bfdrbowen <title>Summary</title>

83f3471f5de14ca3def6d7935cd1af1604874bfdrbowen <p>The <directive>RewriteMap</directive> directive can occur more than

83f3471f5de14ca3def6d7935cd1af1604874bfdrbowen once. For each mapping-function use one

83f3471f5de14ca3def6d7935cd1af1604874bfdrbowen <directive>RewriteMap</directive> directive to declare its rewriting

83f3471f5de14ca3def6d7935cd1af1604874bfdrbowen mapfile. While you cannot <strong>declare</strong> a map in

83f3471f5de14ca3def6d7935cd1af1604874bfdrbowen per-directory context it is of course possible to

83f3471f5de14ca3def6d7935cd1af1604874bfdrbowen <strong>use</strong> this map in per-directory context. </p>

83f3471f5de14ca3def6d7935cd1af1604874bfdrbowen <note><title>Note</title> For plain text and DBM format files the

83f3471f5de14ca3def6d7935cd1af1604874bfdrbowenlooked-up keys are cached in-core until the <code>mtime</code> of the

83f3471f5de14ca3def6d7935cd1af1604874bfdrbowenmapfile changes or the server does a restart. This way you can have

83f3471f5de14ca3def6d7935cd1af1604874bfdrbowenmap-functions in rules which are used for <strong>every</strong>

83f3471f5de14ca3def6d7935cd1af1604874bfdrbowenrequest. This is no problem, because the external lookup only happens

83f3471f5de14ca3def6d7935cd1af1604874bfdrbowenonce!

83f3471f5de14ca3def6d7935cd1af1604874bfdrbowen</note>

83f3471f5de14ca3def6d7935cd1af1604874bfdrbowen </section>

83f3471f5de14ca3def6d7935cd1af1604874bfdrbowen</manualpage>

83f3471f5de14ca3def6d7935cd1af1604874bfdrbowen