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

<modulesynopsis metafile="mod_proxy_express.xml.meta">

<name>mod_proxy_express</name>

<description>Dynamic mass reverse proxy extension for

<module>mod_proxy</module></description>

<status>Extension</status>

<sourcefile>mod_proxy_express.c</sourcefile>

<identifier>proxy_express_module</identifier>

<summary>

<p>This module creates dynamically configured mass reverse

proxies, by mapping the Host: header of the HTTP request to

a server name and backend URL stored in a DBM file.

This allows for easy use of a huge number of reverse proxies

with no configuration changes. It is much less feature-full

than <module>mod_proxy_balancer</module>, which also provides

dynamic growth, but is intended to handle much, much

larger numbers of backends. It is ideally suited as a

front-end HTTP switch.</p>

<p>This module <em>requires</em> the service of <module

>mod_proxy</module>.</p>

<note type="warning"><title>Warning</title>

<p>Do not enable proxying until you have <a

href="mod_proxy.html#access">secured your server</a>. Open proxy

servers are dangerous both to your network and to the Internet at

large.</p>

</note>

<note><title>Limitations</title>

<ul>

<li>This module is not intended to replace the dynamic capability of

<module>mod_proxy_balancer</module>. Instead, it is intended to be mostly

a lightweight and fast alternative to using <module>mod_rewrite</module>

with <directive>RewriteMap</directive> and the <code>[P]</code> flag

for mapped reverse proxying.

</li>

<li>It does not support regex or pattern matching at all.

</li>

<li>It emulates:

<highlight language="config">

&lt;VirtualHost *:80&gt;

ServerName front.end.server

ProxyPass "/" "back.end.server:port"

ProxyPassReverse "/" "back.end.server:port"

&lt;/VirtualHost&gt;

</highlight>

That is, the entire URL is appended to the mapped backend

URL. This is in keeping with the intent of being a simple

but fast reverse proxy switch.

</li>

</ul>

</note>

</summary>

<seealso><module>mod_proxy</module></seealso>

<directivesynopsis>

<name>ProxyExpressEnable</name>

<description>Enable the module functionality.</description>

<syntax>ProxyExpressEnable [on|off]</syntax>

<default>off</default>

<contextlist><context>server config</context><context>virtual host</context>

</contextlist>

<compatibility>Available in Apache 2.3.13 and later</compatibility>

<usage>

<p>The <directive>ProxyExpressEnable</directive> directive

controls whether the module will be active.</p>

</usage>

</directivesynopsis>

<directivesynopsis>

<name>ProxyExpressDBMFile</name>

<description>Pathname to DBM file.</description>

<syntax>ProxyExpressDBMFile &lt;pathname&gt;</syntax>

<default>None</default>

<contextlist><context>server config</context><context>virtual host</context>

</contextlist>

<compatibility>Available in Apache 2.3.13 and later</compatibility>

<usage>

<p>The <directive>ProxyExpressDBMFile</directive> directive

points to the location of the Express map DBM file. This

file serves to map the incoming server name, obtained from

the Host: header, to a backend URL.</p>

<note><title>Note</title>

<p>The file is constructed from a plain text file format using

the <code><a href="/programs/httxt2dbm.html">httxt2dbm</a></code>

utility.</p>

<example><title>ProxyExpress map file</title>

##<br />

##express-map.txt:<br />

##<br />

<br />

www1.example.com http://192.168.211.2:8080<br />

www2.example.com http://192.168.211.12:8088<br />

www3.example.com http://192.168.212.10<br />

</example>

<example><title>Create DBM file</title>

httxt2dbm -i express-map.txt -o emap<br />

</example>

<example><title>Configuration</title>

ProxyExpressEnable on<br />

ProxyExpressDBMFile emap<br />

</example>

</note>

</usage>

</directivesynopsis>

<directivesynopsis>

<name>ProxyExpressDBMType</name>

<description>DBM type of file.</description>

<syntax>ProxyExpressDBMFile &lt;type&gt;</syntax>

<default>"default"</default>

<contextlist><context>server config</context><context>virtual host</context>

</contextlist>

<compatibility>Available in Apache 2.3.13 and later</compatibility>

<usage>

<p>The <directive>ProxyExpressDBMType</directive> directive

controls the DBM type expected by the module. The default

is the default DBM type created with <code>

<a href="/programs/httxt2dbm.html">httxt2dbm</a></code>.</p>

<p>Possible values are (not all may be available at run time):</p>

<table border="1" style="zebra">

<columnspec><column width=".3"/><column width=".7"/></columnspec>

<tr><th>Value</th><th>Description</th></tr>

<tr><td><code>db</code></td><td> Berkeley DB files</td></tr>

<tr><td><code>gdbm</code></td><td> GDBM files</td></tr>

<tr><td><code>ndbm</code></td><td> NDBM files</td></tr>

<tr><td><code>sdbm</code></td><td> SDBM files (always available)</td></tr>

<tr><td><code>default</code></td><td> default DBM type</td></tr>

</table>

</usage>

</directivesynopsis>

</modulesynopsis>