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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 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>www.<strong>SITE</strong>.example.com</code> for each
66 user, and serve their content out of
67 <code>/home/<strong>SITE</strong>/www</code>.</p>
74 <highlight language="config">
77 RewriteMap lowercase "int:tolower"
79 RewriteCond "${lowercase:%{<strong>HTTP_HOST</strong>}}" "^www\.<strong>([^.]+)</strong>\.example\.com$"
80 RewriteRule "^(.*)" "/home/<strong>%1</strong>/www$1"
86 <note type="warning">You will need to take care of the DNS
87 resolution - Apache does
88 not handle name resolution. You'll need either to create CNAME
89 records for each hostname, or a DNS wildcard record. Creating DNS
90 records is beyond the scope of this document.</note>
92 <p>The internal <code>tolower</code> RewriteMap directive is used to
93 ensure that the hostnames being used are all lowercase, so that there is
94 no ambiguity in the directory structure which must be created.</p>
96 <p>Parentheses used in a <directive
97 module="mod_rewrite">RewriteCond</directive> are captured into the
98 backreferences <code>%1</code>, <code>%2</code>, etc, while parentheses
99 used in <directive module="mod_rewrite">RewriteRule</directive> are
100 captured into the backreferences <code>$1</code>, <code>$2</code>,
104 As with many techniques discussed in this document, mod_rewrite really
105 isn't the best way to accomplish this task. You should, instead,
106 consider using <module>mod_vhost_alias</module> instead, as it will much
107 more gracefully handle anything beyond serving static files, such as any
108 dynamic content, and Alias resolution.
115 <section id="simple.rewrite"><title>Dynamic
116 Virtual Hosts Using <module>mod_rewrite</module></title>
118 <p>This extract from <code>httpd.conf</code> does the same
119 thing as <a href="#per-hostname">the first example</a>. The first
120 half is very similar to the corresponding part above, except for
121 some changes, required for backward compatibility and to make the
122 <code>mod_rewrite</code> part work properly; the second half
123 configures <code>mod_rewrite</code> to do the actual work.</p>
125 <p>Because <code>mod_rewrite</code> runs before other URI translation
126 modules (e.g., <code>mod_alias</code>), <code>mod_rewrite</code> must
127 be told to explicitly ignore any URLs that would have been handled
128 by those modules. And, because these rules would otherwise bypass
129 any <code>ScriptAlias</code> directives, we must have
130 <code>mod_rewrite</code> explicitly enact those mappings.</p>
132 <highlight language="config">
133 # get the server name from the Host: header
137 LogFormat "%{Host}i %h %l %u %t \"%r\" %s %b" vcommon
138 CustomLog logs/access_log vcommon
140 <Directory "/www/hosts">
141 # ExecCGI is needed here because we can't force
142 # CGI execution in the way that ScriptAlias does
143 Options FollowSymLinks ExecCGI
148 # a ServerName derived from a Host: header may be any case at all
149 RewriteMap lowercase "int:tolower"
151 ## deal with normal documents first:
152 # allow Alias /icons/ to work - repeat for other aliases
153 RewriteCond "%{REQUEST_URI}" "!^/icons/"
155 RewriteCond "%{REQUEST_URI}" "!^/cgi-bin/"
157 RewriteRule "^/(.*)$" "/www/hosts/${lowercase:%{SERVER_NAME}}/docs/$1"
159 ## and now deal with CGIs - we have to force a handler
160 RewriteCond "%{REQUEST_URI}" "^/cgi-bin/"
161 RewriteRule "^/(.*)$" "/www/hosts/${lowercase:%{SERVER_NAME}}/cgi-bin/$1" [H=cgi-script]
166 <section id="xtra-conf"><title>Using a Separate Virtual Host Configuration File</title>
168 <p>This arrangement uses more advanced <module>mod_rewrite</module>
169 features to work out the translation from virtual host to document
170 root, from a separate configuration file. This provides more
171 flexibility, but requires more complicated configuration.</p>
173 <p>The <code>vhost.map</code> file should look something like
177 customer-1.example.com /www/customers/1<br />
178 customer-2.example.com /www/customers/2<br />
180 customer-N.example.com /www/customers/N<br />
183 <p>The <code>httpd.conf</code> should contain the following:</p>
185 <highlight language="config">
188 RewriteMap lowercase "int:tolower"
190 # define the map file
191 RewriteMap vhost "txt:/www/conf/vhost.map"
193 # deal with aliases as above
194 RewriteCond "%{REQUEST_URI}" "!^/icons/"
195 RewriteCond "%{REQUEST_URI}" "!^/cgi-bin/"
196 RewriteCond "${lowercase:%{SERVER_NAME}}" "^(.+)$"
197 # this does the file-based remap
198 RewriteCond "${vhost:%1}" "^(/.*)$"
199 RewriteRule "^/(.*)$" "%1/docs/$1"
201 RewriteCond "%{REQUEST_URI}" "^/cgi-bin/"
202 RewriteCond "${lowercase:%{SERVER_NAME}}" "^(.+)$"
203 RewriteCond "${vhost:%1}" "^(/.*)$"
204 RewriteRule "^/(.*)$" "%1/cgi-bin/$1" [H=cgi-script]