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23 <manualpage metafile="vhosts.xml.meta">
24 <parentdocument href="./">Rewrite</parentdocument>
26 <title>Dynamic mass virtual hosts with mod_rewrite</title>
30 <p>This document supplements the <module>mod_rewrite</module>
31 <a href="../mod/mod_rewrite.html">reference documentation</a>. It describes
32 how you can use <module>mod_rewrite</module> to create dynamically
33 configured virtual hosts.</p>
35 <note type="warning">mod_rewrite is usually not the best way to configure
36 virtual hosts. You should first consider the <a
37 href="../vhosts/mass.html">alternatives</a> before resorting to
38 mod_rewrite. See also the "<a href="avoid.html#vhosts">how to avoid
39 mod_rewrite</a> document.</note>
42 <seealso><a href="../mod/mod_rewrite.html">Module documentation</a></seealso>
43 <seealso><a href="intro.html">mod_rewrite introduction</a></seealso>
44 <seealso><a href="remapping.html">Redirection and remapping</a></seealso>
45 <seealso><a href="access.html">Controlling access</a></seealso>
46 <!--<seealso><a href="vhosts.html">Virtual hosts</a></seealso>-->
47 <seealso><a href="proxy.html">Proxying</a></seealso>
48 <seealso><a href="rewritemap.html">RewriteMap</a></seealso>
49 <seealso><a href="advanced.html">Advanced techniques</a></seealso>
50 <seealso><a href="avoid.html">When not to use mod_rewrite</a></seealso>
52 <section id="per-hostname">
54 <title>Virtual Hosts For Arbitrary Hostnames</title>
60 <p>We want to automatically create a virtual host for every hostname
61 which resolves in our domain, without having to create
62 new VirtualHost sections.</p>
64 <p>In this recipe, we assume that we'll be using the hostname
65 <code><strong>SITE</strong>.example.com</code> for each
66 user, and serve their content out of
67 <code>/home/<strong>SITE</strong>/www</code>. However, we want
68 <code>www.example.com</code> to be ommitted from this mapping.</p>
75 <highlight language="config">
78 RewriteMap lowercase int:tolower
80 RewriteCond %{HTTP_HOST} !^www\.
81 RewriteCond ${lowercase:%{<strong>HTTP_HOST</strong>}} ^<strong>([^.]+)</strong>\.example\.com$
82 RewriteRule ^(.*) /home/<strong>%1</strong>/www$1
88 <note type="warning">You will need to take care of the DNS
89 resolution - Apache does
90 not handle name resolution. You'll need either to create CNAME
91 records for each hostname, or a DNS wildcard record. Creating DNS
92 records is beyond the scope of this document.</note>
94 <p>The internal <code>tolower</code> RewriteMap directive is used to
95 ensure that the hostnames being used are all lowercase, so that there is
96 no ambiguity in the directory structure which must be created.</p>
98 <p>Parentheses used in a <directive
99 module="mod_rewrite">RewriteCond</directive> are captured into the
100 backreferences <code>%1</code>, <code>%2</code>, etc, while parentheses
101 used in <directive module="mod_rewrite">RewriteRule</directive> are
102 captured into the backreferences <code>$1</code>, <code>$2</code>,
105 <p>The first <code>RewriteCond</code> checks to see if the hostname
106 starts with <code>www.</code>, and if it does, the rewriting is
110 As with many techniques discussed in this document, mod_rewrite really
111 isn't the best way to accomplish this task. You should, instead,
112 consider using <module>mod_vhost_alias</module> instead, as it will much
113 more gracefully handle anything beyond serving static files, such as any
114 dynamic content, and Alias resolution.
121 <section id="simple.rewrite"><title>Dynamic
122 Virtual Hosts Using <module>mod_rewrite</module></title>
124 <p>This extract from <code>httpd.conf</code> does the same
125 thing as <a href="#per-hostname">the first example</a>. The first
126 half is very similar to the corresponding part above, except for
127 some changes, required for backward compatibility and to make the
128 <code>mod_rewrite</code> part work properly; the second half
129 configures <code>mod_rewrite</code> to do the actual work.</p>
131 <p>Because <code>mod_rewrite</code> runs before other URI translation
132 modules (e.g., <code>mod_alias</code>), <code>mod_rewrite</code> must
133 be told to explicitly ignore any URLs that would have been handled
134 by those modules. And, because these rules would otherwise bypass
135 any <code>ScriptAlias</code> directives, we must have
136 <code>mod_rewrite</code> explicitly enact those mappings.</p>
138 <highlight language="config">
139 # get the server name from the Host: header
143 LogFormat "%{Host}i %h %l %u %t \"%r\" %s %b" vcommon
144 CustomLog "logs/access_log" vcommon
146 <Directory "/www/hosts">
147 # ExecCGI is needed here because we can't force
148 # CGI execution in the way that ScriptAlias does
149 Options FollowSymLinks ExecCGI
154 # a ServerName derived from a Host: header may be any case at all
155 RewriteMap lowercase "int:tolower"
157 ## deal with normal documents first:
158 # allow Alias /icons/ to work - repeat for other aliases
159 RewriteCond "%{REQUEST_URI}" "!^/icons/"
161 RewriteCond "%{REQUEST_URI}" "!^/cgi-bin/"
163 RewriteRule "^/(.*)$" "/www/hosts/${lowercase:%{SERVER_NAME}}/docs/$1"
165 ## and now deal with CGIs - we have to force a handler
166 RewriteCond "%{REQUEST_URI}" "^/cgi-bin/"
167 RewriteRule "^/(.*)$" "/www/hosts/${lowercase:%{SERVER_NAME}}/cgi-bin/$1" [H=cgi-script]
172 <section id="xtra-conf"><title>Using a Separate Virtual Host Configuration File</title>
174 <p>This arrangement uses more advanced <module>mod_rewrite</module>
175 features to work out the translation from virtual host to document
176 root, from a separate configuration file. This provides more
177 flexibility, but requires more complicated configuration.</p>
179 <p>The <code>vhost.map</code> file should look something like
183 customer-1.example.com /www/customers/1<br />
184 customer-2.example.com /www/customers/2<br />
186 customer-N.example.com /www/customers/N<br />
189 <p>The <code>httpd.conf</code> should contain the following:</p>
191 <highlight language="config">
194 RewriteMap lowercase "int:tolower"
196 # define the map file
197 RewriteMap vhost "txt:/www/conf/vhost.map"
199 # deal with aliases as above
200 RewriteCond "%{REQUEST_URI}" "!^/icons/"
201 RewriteCond "%{REQUEST_URI}" "!^/cgi-bin/"
202 RewriteCond "${lowercase:%{SERVER_NAME}}" "^(.+)$"
203 # this does the file-based remap
204 RewriteCond "${vhost:%1}" "^(/.*)$"
205 RewriteRule "^/(.*)$" "%1/docs/$1"
207 RewriteCond "%{REQUEST_URI}" "^/cgi-bin/"
208 RewriteCond "${lowercase:%{SERVER_NAME}}" "^(.+)$"
209 RewriteCond "${vhost:%1}" "^(/.*)$"
210 RewriteRule "^/cgi-bin/(.*)$" "%1/cgi-bin/$1" [H=cgi-script]