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git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@832069 13f79535-47bb-0310-9956-ffa450edef68
836 lines
32 KiB
XML
836 lines
32 KiB
XML
<?xml version="1.0" encoding="ISO-8859-1"?>
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<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
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<html xmlns="http://www.w3.org/1999/xhtml" lang="en" xml:lang="en"><head><!--
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XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
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This file is generated from xml source: DO NOT EDIT
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XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
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-->
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<title>URL Rewriting Guide - Apache HTTP Server</title>
|
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<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 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="../faq/">FAQ</a> | <a href="../glossary.html">Glossary</a> | <a href="../sitemap.html">Sitemap</a></p>
|
|
<p class="apache">Apache HTTP Server Version 2.3</p>
|
|
<img alt="" src="../images/feather.gif" /></div>
|
|
<div class="up"><a href="./"><img title="<-" alt="<-" src="../images/left.gif" /></a></div>
|
|
<div id="path">
|
|
<a href="http://www.apache.org/">Apache</a> > <a href="http://httpd.apache.org/">HTTP Server</a> > <a href="http://httpd.apache.org/docs/">Documentation</a> > <a href="../">Version 2.3</a> > <a href="./">Rewrite</a></div><div id="page-content"><div id="preamble"><h1>URL Rewriting Guide</h1>
|
|
<div class="toplang">
|
|
<p><span>Available Languages: </span><a href="../en/rewrite/rewrite_guide.html" title="English"> en </a> |
|
|
<a href="../fr/rewrite/rewrite_guide.html" hreflang="fr" rel="alternate" title="Français"> fr </a></p>
|
|
</div>
|
|
|
|
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<p>This document supplements the <code class="module"><a href="../mod/mod_rewrite.html">mod_rewrite</a></code>
|
|
<a href="../mod/mod_rewrite.html">reference documentation</a>.
|
|
It describes how one can use Apache's <code class="module"><a href="../mod/mod_rewrite.html">mod_rewrite</a></code>
|
|
to solve typical URL-based problems with which webmasters are
|
|
commonly confronted. We give detailed descriptions on how to
|
|
solve each problem by configuring URL rewriting rulesets.</p>
|
|
|
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<div class="warning">ATTENTION: Depending on your server configuration
|
|
it may be necessary to slightly change the examples for your
|
|
situation, e.g. adding the <code>[PT]</code> flag when
|
|
additionally using <code class="module"><a href="../mod/mod_alias.html">mod_alias</a></code> and
|
|
<code class="module"><a href="../mod/mod_userdir.html">mod_userdir</a></code>, etc. Or rewriting a ruleset
|
|
to fit in <code>.htaccess</code> context instead
|
|
of per-server context. Always try to understand what a
|
|
particular ruleset really does before you use it. This
|
|
avoids many problems.</div>
|
|
|
|
</div>
|
|
<div id="quickview"><ul id="toc"><li><img alt="" src="../images/down.gif" /> <a href="#canonicalurl">Canonical URLs</a></li>
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<li><img alt="" src="../images/down.gif" /> <a href="#canonicalhost">Canonical Hostnames</a></li>
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<li><img alt="" src="../images/down.gif" /> <a href="#moveddocroot">Moved <code>DocumentRoot</code></a></li>
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|
<li><img alt="" src="../images/down.gif" /> <a href="#trailingslash">Trailing Slash Problem</a></li>
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|
<li><img alt="" src="../images/down.gif" /> <a href="#movehomedirs">Move Homedirs to Different Webserver</a></li>
|
|
<li><img alt="" src="../images/down.gif" /> <a href="#multipledirs">Search for pages in more than one directory</a></li>
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|
<li><img alt="" src="../images/down.gif" /> <a href="#setenvvars">Set Environment Variables According To URL Parts</a></li>
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|
<li><img alt="" src="../images/down.gif" /> <a href="#uservhosts">Virtual Hosts Per User</a></li>
|
|
<li><img alt="" src="../images/down.gif" /> <a href="#redirecthome">Redirect Homedirs For Foreigners</a></li>
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|
<li><img alt="" src="../images/down.gif" /> <a href="#redirectanchors">Redirecting Anchors</a></li>
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<li><img alt="" src="../images/down.gif" /> <a href="#time-dependent">Time-Dependent Rewriting</a></li>
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<li><img alt="" src="../images/down.gif" /> <a href="#backward-compatibility">Backward Compatibility for YYYY to XXXX migration</a></li>
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|
<li><img alt="" src="../images/down.gif" /> <a href="#old-to-new">From Old to New (intern)</a></li>
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<li><img alt="" src="../images/down.gif" /> <a href="#old-to-new-extern">From Old to New (extern)</a></li>
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|
<li><img alt="" src="../images/down.gif" /> <a href="#static-to-dynamic">From Static to Dynamic</a></li>
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<li><img alt="" src="../images/down.gif" /> <a href="#blocking-of-robots">Blocking of Robots</a></li>
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<li><img alt="" src="../images/down.gif" /> <a href="#blocked-inline-images">Forbidding Image "Hotlinking"</a></li>
|
|
<li><img alt="" src="../images/down.gif" /> <a href="#proxy-deny">Proxy Deny</a></li>
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<li><img alt="" src="../images/down.gif" /> <a href="#external-rewriting">External Rewriting Engine</a></li>
|
|
</ul><h3>See also</h3><ul class="seealso"><li><a href="../mod/mod_rewrite.html">Module
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|
documentation</a></li><li><a href="intro.html">mod_rewrite
|
|
introduction</a></li><li><a href="rewrite_guide_advanced.html">Advanced Rewrite Guide - advanced
|
|
useful examples</a></li><li><a href="tech.html">Technical details</a></li></ul></div>
|
|
<div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
|
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<div class="section">
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<h2><a name="canonicalurl" id="canonicalurl">Canonical URLs</a></h2>
|
|
|
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<dl>
|
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<dt>Description:</dt>
|
|
|
|
<dd>
|
|
<p>On some webservers there are more than one URL for a
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|
resource. Usually there are canonical URLs (which should be
|
|
actually used and distributed) and those which are just
|
|
shortcuts, internal ones, etc. Independent of which URL the
|
|
user supplied with the request he should finally see the
|
|
canonical one only.</p>
|
|
</dd>
|
|
|
|
<dt>Solution:</dt>
|
|
|
|
<dd>
|
|
<p>We do an external HTTP redirect for all non-canonical
|
|
URLs to fix them in the location view of the Browser and
|
|
for all subsequent requests. In the example ruleset below
|
|
we replace <code>/~user</code> by the canonical
|
|
<code>/u/user</code> and fix a missing trailing slash for
|
|
<code>/u/user</code>.</p>
|
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<div class="example"><pre>
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RewriteRule ^/<strong>~</strong>([^/]+)/?(.*) /<strong>u</strong>/$1/$2 [<strong>R</strong>]
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RewriteRule ^/u/(<strong>[^/]+</strong>)$ /$1/$2<strong>/</strong> [<strong>R</strong>]
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|
</pre></div>
|
|
</dd>
|
|
</dl>
|
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|
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</div><div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
|
|
<div class="section">
|
|
<h2><a name="canonicalhost" id="canonicalhost">Canonical Hostnames</a></h2>
|
|
|
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<dl>
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|
<dt>Description:</dt>
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|
|
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<dd>The goal of this rule is to force the use of a particular
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|
hostname, in preference to other hostnames which may be used to
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|
reach the same site. For example, if you wish to force the use
|
|
of <strong>www.example.com</strong> instead of
|
|
<strong>example.com</strong>, you might use a variant of the
|
|
following recipe.</dd>
|
|
|
|
<dt>Solution:</dt>
|
|
|
|
<dd>
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|
<p>For sites running on a port other than 80:</p>
|
|
<div class="example"><pre>
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|
RewriteCond %{HTTP_HOST} !^www\.example\.com [NC]
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RewriteCond %{HTTP_HOST} !^$
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|
RewriteCond %{SERVER_PORT} !^80$
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|
RewriteRule ^/?(.*) http://www.example.com:%{SERVER_PORT}/$1 [L,R,NE]
|
|
</pre></div>
|
|
|
|
<p>And for a site running on port 80</p>
|
|
<div class="example"><pre>
|
|
RewriteCond %{HTTP_HOST} !^www\.example\.com [NC]
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|
RewriteCond %{HTTP_HOST} !^$
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RewriteRule ^/?(.*) http://www.example.com/$1 [L,R,NE]
|
|
</pre></div>
|
|
|
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<p>
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|
If you wanted to do this generically for all domain names - that
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|
is, if you want to redirect <strong>example.com</strong> to
|
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<strong>www.example.com</strong> for all possible values of
|
|
<strong>example.com</strong>, you could use the following
|
|
recipe:</p>
|
|
|
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<div class="example"><pre>
|
|
RewriteCond %{HTTP_HOST} !^www\. [NC]
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|
RewriteCond %{HTTP_HOST} !^$
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|
RewriteRule ^/?(.*) http://www.%{HTTP_HOST}/$1 [L,R,NE]
|
|
</pre></div>
|
|
|
|
<p>These rulesets will work either in your main server configuration
|
|
file, or in a <code>.htaccess</code> file placed in the <code class="directive"><a href="../mod/core.html#documentroot">DocumentRoot</a></code> of the server.</p>
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</dd>
|
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</dl>
|
|
|
|
</div><div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
|
|
<div class="section">
|
|
<h2><a name="moveddocroot" id="moveddocroot">Moved <code>DocumentRoot</code></a></h2>
|
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|
|
|
|
|
|
<dl>
|
|
<dt>Description:</dt>
|
|
|
|
<dd>
|
|
<p>Usually the <code class="directive"><a href="../mod/core.html#documentroot">DocumentRoot</a></code>
|
|
of the webserver directly relates to the URL "<code>/</code>".
|
|
But often this data is not really of top-level priority. For example,
|
|
you may wish for visitors, on first entering a site, to go to a
|
|
particular subdirectory <code>/about/</code>. This may be accomplished
|
|
using the following ruleset:</p>
|
|
</dd>
|
|
|
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<dt>Solution:</dt>
|
|
|
|
<dd>
|
|
<p>We redirect the URL <code>/</code> to
|
|
<code>/about/</code>:
|
|
</p>
|
|
|
|
<div class="example"><pre>
|
|
RewriteEngine on
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|
RewriteRule <strong>^/$</strong> /about/ [<strong>R</strong>]
|
|
</pre></div>
|
|
|
|
<p>Note that this can also be handled using the <code class="directive"><a href="../mod/mod_alias.html#redirectmatch">RedirectMatch</a></code> directive:</p>
|
|
|
|
<div class="example"><p><code>
|
|
RedirectMatch ^/$ http://example.com/about/
|
|
</code></p></div>
|
|
|
|
<p>Note also that the example rewrites only the root URL. That is, it
|
|
rewrites a request for <code>http://example.com/</code>, but not a
|
|
request for <code>http://example.com/page.html</code>. If you have in
|
|
fact changed your document root - that is, if <strong>all</strong> of
|
|
your content is in fact in that subdirectory, it is greatly preferable
|
|
to simply change your <code class="directive"><a href="../mod/core.html#documentroot">DocumentRoot</a></code>
|
|
directive, rather than rewriting URLs.</p>
|
|
</dd>
|
|
</dl>
|
|
|
|
</div><div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
|
|
<div class="section">
|
|
<h2><a name="trailingslash" id="trailingslash">Trailing Slash Problem</a></h2>
|
|
|
|
|
|
|
|
<dl>
|
|
<dt>Description:</dt>
|
|
|
|
<dd><p>The vast majority of "trailing slash" problems can be dealt
|
|
with using the techniques discussed in the <a href="http://httpd.apache.org/docs/misc/FAQ-E.html#set-servername">FAQ
|
|
entry</a>. However, occasionally, there is a need to use mod_rewrite
|
|
to handle a case where a missing trailing slash causes a URL to
|
|
fail. This can happen, for example, after a series of complex
|
|
rewrite rules.</p>
|
|
</dd>
|
|
|
|
<dt>Solution:</dt>
|
|
|
|
<dd>
|
|
<p>The solution to this subtle problem is to let the server
|
|
add the trailing slash automatically. To do this
|
|
correctly we have to use an external redirect, so the
|
|
browser correctly requests subsequent images etc. If we
|
|
only did a internal rewrite, this would only work for the
|
|
directory page, but would go wrong when any images are
|
|
included into this page with relative URLs, because the
|
|
browser would request an in-lined object. For instance, a
|
|
request for <code>image.gif</code> in
|
|
<code>/~quux/foo/index.html</code> would become
|
|
<code>/~quux/image.gif</code> without the external
|
|
redirect!</p>
|
|
|
|
<p>So, to do this trick we write:</p>
|
|
|
|
<div class="example"><pre>
|
|
RewriteEngine on
|
|
RewriteBase /~quux/
|
|
RewriteRule ^foo<strong>$</strong> foo<strong>/</strong> [<strong>R</strong>]
|
|
</pre></div>
|
|
|
|
<p>Alternately, you can put the following in a
|
|
top-level <code>.htaccess</code> file in the content directory.
|
|
But note that this creates some processing overhead.</p>
|
|
|
|
<div class="example"><pre>
|
|
RewriteEngine on
|
|
RewriteBase /~quux/
|
|
RewriteCond %{REQUEST_FILENAME} <strong>-d</strong>
|
|
RewriteRule ^(.+<strong>[^/]</strong>)$ $1<strong>/</strong> [R]
|
|
</pre></div>
|
|
</dd>
|
|
</dl>
|
|
|
|
</div><div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
|
|
<div class="section">
|
|
<h2><a name="movehomedirs" id="movehomedirs">Move Homedirs to Different Webserver</a></h2>
|
|
|
|
|
|
|
|
<dl>
|
|
<dt>Description:</dt>
|
|
|
|
<dd>
|
|
<p>Many webmasters have asked for a solution to the
|
|
following situation: They wanted to redirect just all
|
|
homedirs on a webserver to another webserver. They usually
|
|
need such things when establishing a newer webserver which
|
|
will replace the old one over time.</p>
|
|
</dd>
|
|
|
|
<dt>Solution:</dt>
|
|
|
|
<dd>
|
|
<p>The solution is trivial with <code class="module"><a href="../mod/mod_rewrite.html">mod_rewrite</a></code>.
|
|
On the old webserver we just redirect all
|
|
<code>/~user/anypath</code> URLs to
|
|
<code>http://newserver/~user/anypath</code>.</p>
|
|
|
|
<div class="example"><pre>
|
|
RewriteEngine on
|
|
RewriteRule ^/~(.+) http://<strong>newserver</strong>/~$1 [R,L]
|
|
</pre></div>
|
|
</dd>
|
|
</dl>
|
|
|
|
</div><div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
|
|
<div class="section">
|
|
<h2><a name="multipledirs" id="multipledirs">Search for pages in more than one directory</a></h2>
|
|
|
|
|
|
|
|
<dl>
|
|
<dt>Description:</dt>
|
|
|
|
<dd>
|
|
<p>Sometimes it is necessary to let the webserver search
|
|
for pages in more than one directory. Here MultiViews or
|
|
other techniques cannot help.</p>
|
|
</dd>
|
|
|
|
<dt>Solution:</dt>
|
|
|
|
<dd>
|
|
<p>We program a explicit ruleset which searches for the
|
|
files in the directories.</p>
|
|
|
|
<div class="example"><pre>
|
|
RewriteEngine on
|
|
|
|
# first try to find it in dir1/...
|
|
# ...and if found stop and be happy:
|
|
RewriteCond %{DOCUMENT_ROOT}/<strong>dir1</strong>/%{REQUEST_URI} -f
|
|
RewriteRule ^(.+) %{DOCUMENT_ROOT}/<strong>dir1</strong>/$1 [L]
|
|
|
|
# second try to find it in dir2/...
|
|
# ...and if found stop and be happy:
|
|
RewriteCond %{DOCUMENT_ROOT}/<strong>dir2</strong>/%{REQUEST_URI} -f
|
|
RewriteRule ^(.+) %{DOCUMENT_ROOT}/<strong>dir2</strong>/$1 [L]
|
|
|
|
# else go on for other Alias or ScriptAlias directives,
|
|
# etc.
|
|
RewriteRule ^(.+) - [PT]
|
|
</pre></div>
|
|
</dd>
|
|
</dl>
|
|
|
|
</div><div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
|
|
<div class="section">
|
|
<h2><a name="setenvvars" id="setenvvars">Set Environment Variables According To URL Parts</a></h2>
|
|
|
|
|
|
|
|
<dl>
|
|
<dt>Description:</dt>
|
|
|
|
<dd>
|
|
<p>Perhaps you want to keep status information between
|
|
requests and use the URL to encode it. But you don't want
|
|
to use a CGI wrapper for all pages just to strip out this
|
|
information.</p>
|
|
</dd>
|
|
|
|
<dt>Solution:</dt>
|
|
|
|
<dd>
|
|
<p>We use a rewrite rule to strip out the status information
|
|
and remember it via an environment variable which can be
|
|
later dereferenced from within XSSI or CGI. This way a
|
|
URL <code>/foo/S=java/bar/</code> gets translated to
|
|
<code>/foo/bar/</code> and the environment variable named
|
|
<code>STATUS</code> is set to the value "java".</p>
|
|
|
|
<div class="example"><pre>
|
|
RewriteEngine on
|
|
RewriteRule ^(.*)/<strong>S=([^/]+)</strong>/(.*) $1/$3 [E=<strong>STATUS:$2</strong>]
|
|
</pre></div>
|
|
</dd>
|
|
</dl>
|
|
|
|
</div><div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
|
|
<div class="section">
|
|
<h2><a name="uservhosts" id="uservhosts">Virtual Hosts Per User</a></h2>
|
|
|
|
|
|
|
|
<dl>
|
|
<dt>Description:</dt>
|
|
|
|
<dd>
|
|
<p>Assume that you want to provide
|
|
<code>www.<strong>username</strong>.host.domain.com</code>
|
|
for the homepage of username via just DNS A records to the
|
|
same machine and without any virtualhosts on this
|
|
machine.</p>
|
|
</dd>
|
|
|
|
<dt>Solution:</dt>
|
|
|
|
<dd>
|
|
<p>For HTTP/1.0 requests there is no solution, but for
|
|
HTTP/1.1 requests which contain a Host: HTTP header we
|
|
can use the following ruleset to rewrite
|
|
<code>http://www.username.host.com/anypath</code>
|
|
internally to <code>/home/username/anypath</code>:</p>
|
|
|
|
<div class="example"><pre>
|
|
RewriteEngine on
|
|
RewriteCond %{<strong>HTTP_HOST</strong>} ^www\.<strong>([^.]+)</strong>\.host\.com$
|
|
RewriteRule ^(.*) /home/<strong>%1</strong>$1
|
|
</pre></div>
|
|
|
|
<p>Parentheses used in a <code class="directive"><a href="../mod/mod_rewrite.html#rewritecond">RewriteCond</a></code> are captured into the
|
|
backreferences <code>%1</code>, <code>%2</code>, etc, while parentheses
|
|
used in <code class="directive"><a href="../mod/mod_rewrite.html#rewriterule">RewriteRule</a></code> are
|
|
captured into the backreferences <code>$1</code>, <code>$2</code>,
|
|
etc.</p>
|
|
</dd>
|
|
</dl>
|
|
|
|
</div><div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
|
|
<div class="section">
|
|
<h2><a name="redirecthome" id="redirecthome">Redirect Homedirs For Foreigners</a></h2>
|
|
|
|
|
|
|
|
<dl>
|
|
<dt>Description:</dt>
|
|
|
|
<dd>
|
|
<p>We want to redirect homedir URLs to another webserver
|
|
<code>www.somewhere.com</code> when the requesting user
|
|
does not stay in the local domain
|
|
<code>ourdomain.com</code>. This is sometimes used in
|
|
virtual host contexts.</p>
|
|
</dd>
|
|
|
|
<dt>Solution:</dt>
|
|
|
|
<dd>
|
|
<p>Just a rewrite condition:</p>
|
|
|
|
<div class="example"><pre>
|
|
RewriteEngine on
|
|
RewriteCond %{REMOTE_HOST} <strong>!^.+\.ourdomain\.com$</strong>
|
|
RewriteRule ^(/~.+) http://www.somewhere.com/$1 [R,L]
|
|
</pre></div>
|
|
</dd>
|
|
</dl>
|
|
|
|
</div><div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
|
|
<div class="section">
|
|
<h2><a name="redirectanchors" id="redirectanchors">Redirecting Anchors</a></h2>
|
|
|
|
|
|
|
|
<dl>
|
|
<dt>Description:</dt>
|
|
|
|
<dd>
|
|
<p>By default, redirecting to an HTML anchor doesn't work,
|
|
because mod_rewrite escapes the <code>#</code> character,
|
|
turning it into <code>%23</code>. This, in turn, breaks the
|
|
redirection.</p>
|
|
</dd>
|
|
|
|
<dt>Solution:</dt>
|
|
|
|
<dd>
|
|
<p>Use the <code>[NE]</code> flag on the
|
|
<code>RewriteRule</code>. NE stands for No Escape.
|
|
</p>
|
|
</dd>
|
|
</dl>
|
|
|
|
</div><div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
|
|
<div class="section">
|
|
<h2><a name="time-dependent" id="time-dependent">Time-Dependent Rewriting</a></h2>
|
|
|
|
|
|
|
|
<dl>
|
|
<dt>Description:</dt>
|
|
|
|
<dd>
|
|
<p>When tricks like time-dependent content should happen a
|
|
lot of webmasters still use CGI scripts which do for
|
|
instance redirects to specialized pages. How can it be done
|
|
via <code class="module"><a href="../mod/mod_rewrite.html">mod_rewrite</a></code>?</p>
|
|
</dd>
|
|
|
|
<dt>Solution:</dt>
|
|
|
|
<dd>
|
|
<p>There are a lot of variables named <code>TIME_xxx</code>
|
|
for rewrite conditions. In conjunction with the special
|
|
lexicographic comparison patterns <code><STRING</code>,
|
|
<code>>STRING</code> and <code>=STRING</code> we can
|
|
do time-dependent redirects:</p>
|
|
|
|
<div class="example"><pre>
|
|
RewriteEngine on
|
|
RewriteCond %{TIME_HOUR}%{TIME_MIN} >0700
|
|
RewriteCond %{TIME_HOUR}%{TIME_MIN} <1900
|
|
RewriteRule ^foo\.html$ foo.day.html
|
|
RewriteRule ^foo\.html$ foo.night.html
|
|
</pre></div>
|
|
|
|
<p>This provides the content of <code>foo.day.html</code>
|
|
under the URL <code>foo.html</code> from
|
|
<code>07:00-19:00</code> and at the remaining time the
|
|
contents of <code>foo.night.html</code>. Just a nice
|
|
feature for a homepage...</p>
|
|
</dd>
|
|
</dl>
|
|
|
|
</div><div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
|
|
<div class="section">
|
|
<h2><a name="backward-compatibility" id="backward-compatibility">Backward Compatibility for YYYY to XXXX migration</a></h2>
|
|
|
|
|
|
|
|
<dl>
|
|
<dt>Description:</dt>
|
|
|
|
<dd>
|
|
<p>How can we make URLs backward compatible (still
|
|
existing virtually) after migrating <code>document.YYYY</code>
|
|
to <code>document.XXXX</code>, e.g. after translating a
|
|
bunch of <code>.html</code> files to <code>.phtml</code>?</p>
|
|
</dd>
|
|
|
|
<dt>Solution:</dt>
|
|
|
|
<dd>
|
|
<p>We just rewrite the name to its basename and test for
|
|
existence of the new extension. If it exists, we take
|
|
that name, else we rewrite the URL to its original state.</p>
|
|
|
|
|
|
<div class="example"><pre>
|
|
# backward compatibility ruleset for
|
|
# rewriting document.html to document.phtml
|
|
# when and only when document.phtml exists
|
|
# but no longer document.html
|
|
RewriteEngine on
|
|
RewriteBase /~quux/
|
|
# parse out basename, but remember the fact
|
|
RewriteRule ^(.*)\.html$ $1 [C,E=WasHTML:yes]
|
|
# rewrite to document.phtml if exists
|
|
# Note: This is a per-directory example, so %{REQUEST_FILENAME} is the full
|
|
# filesystem path as already mapped by the server.
|
|
RewriteCond %{REQUEST_FILENAME}.phtml -f
|
|
RewriteRule ^(.*)$ $1.phtml [S=1]
|
|
# else reverse the previous basename cutout
|
|
RewriteCond %{ENV:WasHTML} ^yes$
|
|
RewriteRule ^(.*)$ $1.html
|
|
</pre></div>
|
|
</dd>
|
|
</dl>
|
|
|
|
</div><div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
|
|
<div class="section">
|
|
<h2><a name="old-to-new" id="old-to-new">From Old to New (intern)</a></h2>
|
|
|
|
|
|
|
|
<dl>
|
|
<dt>Description:</dt>
|
|
|
|
<dd>
|
|
<p>Assume we have recently renamed the page
|
|
<code>foo.html</code> to <code>bar.html</code> and now want
|
|
to provide the old URL for backward compatibility. Actually
|
|
we want that users of the old URL even not recognize that
|
|
the pages was renamed.</p>
|
|
</dd>
|
|
|
|
<dt>Solution:</dt>
|
|
|
|
<dd>
|
|
<p>We rewrite the old URL to the new one internally via the
|
|
following rule:</p>
|
|
|
|
<div class="example"><pre>
|
|
RewriteEngine on
|
|
RewriteBase /~quux/
|
|
RewriteRule ^<strong>foo</strong>\.html$ <strong>bar</strong>.html
|
|
</pre></div>
|
|
</dd>
|
|
</dl>
|
|
|
|
</div><div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
|
|
<div class="section">
|
|
<h2><a name="old-to-new-extern" id="old-to-new-extern">From Old to New (extern)</a></h2>
|
|
|
|
|
|
|
|
<dl>
|
|
<dt>Description:</dt>
|
|
|
|
<dd>
|
|
<p>Assume again that we have recently renamed the page
|
|
<code>foo.html</code> to <code>bar.html</code> and now want
|
|
to provide the old URL for backward compatibility. But this
|
|
time we want that the users of the old URL get hinted to
|
|
the new one, i.e. their browsers Location field should
|
|
change, too.</p>
|
|
</dd>
|
|
|
|
<dt>Solution:</dt>
|
|
|
|
<dd>
|
|
<p>We force a HTTP redirect to the new URL which leads to a
|
|
change of the browsers and thus the users view:</p>
|
|
|
|
<div class="example"><pre>
|
|
RewriteEngine on
|
|
RewriteBase /~quux/
|
|
RewriteRule ^<strong>foo</strong>\.html$ <strong>bar</strong>.html [<strong>R</strong>]
|
|
</pre></div>
|
|
</dd>
|
|
</dl>
|
|
|
|
</div><div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
|
|
<div class="section">
|
|
<h2><a name="static-to-dynamic" id="static-to-dynamic">From Static to Dynamic</a></h2>
|
|
|
|
|
|
|
|
<dl>
|
|
<dt>Description:</dt>
|
|
|
|
<dd>
|
|
<p>How can we transform a static page
|
|
<code>foo.html</code> into a dynamic variant
|
|
<code>foo.cgi</code> in a seamless way, i.e. without notice
|
|
by the browser/user.</p>
|
|
</dd>
|
|
|
|
<dt>Solution:</dt>
|
|
|
|
<dd>
|
|
<p>We just rewrite the URL to the CGI-script and force the
|
|
handler to be <strong>cgi-script</strong> so that it is
|
|
executed as a CGI program.
|
|
This way a request to <code>/~quux/foo.html</code>
|
|
internally leads to the invocation of
|
|
<code>/~quux/foo.cgi</code>.</p>
|
|
|
|
<div class="example"><pre>
|
|
RewriteEngine on
|
|
RewriteBase /~quux/
|
|
RewriteRule ^foo\.<strong>html</strong>$ foo.<strong>cgi</strong> [H=<strong>cgi-script</strong>]
|
|
</pre></div>
|
|
</dd>
|
|
</dl>
|
|
|
|
</div><div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
|
|
<div class="section">
|
|
<h2><a name="blocking-of-robots" id="blocking-of-robots">Blocking of Robots</a></h2>
|
|
|
|
|
|
|
|
<dl>
|
|
<dt>Description:</dt>
|
|
|
|
<dd>
|
|
<p>How can we block a really annoying robot from
|
|
retrieving pages of a specific webarea? A
|
|
<code>/robots.txt</code> file containing entries of the
|
|
"Robot Exclusion Protocol" is typically not enough to get
|
|
rid of such a robot.</p>
|
|
</dd>
|
|
|
|
<dt>Solution:</dt>
|
|
|
|
<dd>
|
|
<p>We use a ruleset which forbids the URLs of the webarea
|
|
<code>/~quux/foo/arc/</code> (perhaps a very deep
|
|
directory indexed area where the robot traversal would
|
|
create big server load). We have to make sure that we
|
|
forbid access only to the particular robot, i.e. just
|
|
forbidding the host where the robot runs is not enough.
|
|
This would block users from this host, too. We accomplish
|
|
this by also matching the User-Agent HTTP header
|
|
information.</p>
|
|
|
|
<div class="example"><pre>
|
|
RewriteCond %{HTTP_USER_AGENT} ^<strong>NameOfBadRobot</strong>.*
|
|
RewriteCond %{REMOTE_ADDR} ^<strong>123\.45\.67\.[8-9]</strong>$
|
|
RewriteRule ^<strong>/~quux/foo/arc/</strong>.+ - [<strong>F</strong>]
|
|
</pre></div>
|
|
</dd>
|
|
</dl>
|
|
|
|
</div><div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
|
|
<div class="section">
|
|
<h2><a name="blocked-inline-images" id="blocked-inline-images">Forbidding Image "Hotlinking"</a></h2>
|
|
|
|
|
|
|
|
<dl>
|
|
<dt>Description:</dt>
|
|
|
|
<dd>
|
|
<p>The following technique forbids the practice of other sites
|
|
including your images inline in their pages. This practice is
|
|
often referred to as "hotlinking", and results in
|
|
your bandwidth being used to serve content for someone else's
|
|
site.</p>
|
|
</dd>
|
|
|
|
<dt>Solution:</dt>
|
|
|
|
<dd>
|
|
<p>This technique relies on the value of the
|
|
<code>HTTP_REFERER</code> variable, which is optional. As
|
|
such, it's possible for some people to circumvent this
|
|
limitation. However, most users will experience the failed
|
|
request, which should, over time, result in the image being
|
|
removed from that other site.</p>
|
|
<p>There are several ways that you can handle this
|
|
situation.</p>
|
|
|
|
<p>In this first example, we simply deny the request, if it didn't
|
|
initiate from a page on our site. For the purpose of this example,
|
|
we assume that our site is <code>www.example.com</code>.</p>
|
|
|
|
<div class="example"><pre>
|
|
RewriteCond %{HTTP_REFERER} <strong>!^$</strong>
|
|
RewriteCond %{HTTP_REFERER} !www.example.com [NC]
|
|
RewriteRule <strong>\.(gif|jpg|png)$</strong> - [F,NC]
|
|
</pre></div>
|
|
|
|
<p>In this second example, instead of failing the request, we display
|
|
an alternate image instead.</p>
|
|
|
|
<div class="example"><pre>
|
|
RewriteCond %{HTTP_REFERER} <strong>!^$</strong>
|
|
RewriteCond %{HTTP_REFERER} !www.example.com [NC]
|
|
RewriteRule <strong>\.(gif|jpg|png)$</strong> /images/go-away.png [R,NC]
|
|
</pre></div>
|
|
|
|
<p>In the third example, we redirect the request to an image on some
|
|
third-party site.</p>
|
|
|
|
<div class="example"><pre>
|
|
RewriteCond %{HTTP_REFERER} <strong>!^$</strong>
|
|
RewriteCond %{HTTP_REFERER} !www.example.com [NC]
|
|
RewriteRule <strong>\.(gif|jpg|png)$</strong> http://other.site.com/image.gif [R,NC]
|
|
</pre></div>
|
|
|
|
<p>Of these techniques, the last two tend to be the most effective
|
|
in getting people to stop hotlinking your images, because they will
|
|
simply not see the image that they expected to see.</p>
|
|
|
|
</dd>
|
|
</dl>
|
|
|
|
</div><div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
|
|
<div class="section">
|
|
<h2><a name="proxy-deny" id="proxy-deny">Proxy Deny</a></h2>
|
|
|
|
|
|
|
|
<dl>
|
|
<dt>Description:</dt>
|
|
|
|
<dd>
|
|
<p>How can we forbid a certain host or even a user of a
|
|
special host from using the Apache proxy?</p>
|
|
</dd>
|
|
|
|
<dt>Solution:</dt>
|
|
|
|
<dd>
|
|
<p>We first have to make sure <code class="module"><a href="../mod/mod_rewrite.html">mod_rewrite</a></code>
|
|
is below(!) <code class="module"><a href="../mod/mod_proxy.html">mod_proxy</a></code> in the Configuration
|
|
file when compiling the Apache webserver. This way it gets
|
|
called <em>before</em> <code class="module"><a href="../mod/mod_proxy.html">mod_proxy</a></code>. Then we
|
|
configure the following for a host-dependent deny...</p>
|
|
|
|
<div class="example"><pre>
|
|
RewriteCond %{REMOTE_HOST} <strong>^badhost\.mydomain\.com$</strong>
|
|
RewriteRule !^http://[^/.]\.mydomain.com.* - [F]
|
|
</pre></div>
|
|
|
|
<p>...and this one for a user@host-dependent deny:</p>
|
|
|
|
<div class="example"><pre>
|
|
RewriteCond %{REMOTE_IDENT}@%{REMOTE_HOST} <strong>^badguy@badhost\.mydomain\.com$</strong>
|
|
RewriteRule !^http://[^/.]\.mydomain.com.* - [F]
|
|
</pre></div>
|
|
</dd>
|
|
</dl>
|
|
|
|
</div><div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
|
|
<div class="section">
|
|
<h2><a name="external-rewriting" id="external-rewriting">External Rewriting Engine</a></h2>
|
|
|
|
|
|
|
|
<dl>
|
|
<dt>Description:</dt>
|
|
|
|
<dd>
|
|
<p>A FAQ: How can we solve the FOO/BAR/QUUX/etc.
|
|
problem? There seems no solution by the use of
|
|
<code class="module"><a href="../mod/mod_rewrite.html">mod_rewrite</a></code>...</p>
|
|
</dd>
|
|
|
|
<dt>Solution:</dt>
|
|
|
|
<dd>
|
|
<p>Use an external <code class="directive"><a href="../mod/mod_rewrite.html#rewritemap">RewriteMap</a></code>, i.e. a program which acts
|
|
like a <code class="directive"><a href="../mod/mod_rewrite.html#rewritemap">RewriteMap</a></code>. It is run once on startup of Apache
|
|
receives the requested URLs on <code>STDIN</code> and has
|
|
to put the resulting (usually rewritten) URL on
|
|
<code>STDOUT</code> (same order!).</p>
|
|
|
|
<div class="example"><pre>
|
|
RewriteEngine on
|
|
RewriteMap quux-map <strong>prg:</strong>/path/to/map.quux.pl
|
|
RewriteRule ^/~quux/(.*)$ /~quux/<strong>${quux-map:$1}</strong>
|
|
</pre></div>
|
|
|
|
<div class="example"><pre>
|
|
#!/path/to/perl
|
|
|
|
# disable buffered I/O which would lead
|
|
# to deadloops for the Apache server
|
|
$| = 1;
|
|
|
|
# read URLs one per line from stdin and
|
|
# generate substitution URL on stdout
|
|
while (<>) {
|
|
s|^foo/|bar/|;
|
|
print $_;
|
|
}
|
|
</pre></div>
|
|
|
|
<p>This is a demonstration-only example and just rewrites
|
|
all URLs <code>/~quux/foo/...</code> to
|
|
<code>/~quux/bar/...</code>. Actually you can program
|
|
whatever you like. But notice that while such maps can be
|
|
<strong>used</strong> also by an average user, only the
|
|
system administrator can <strong>define</strong> it.</p>
|
|
</dd>
|
|
</dl>
|
|
|
|
</div></div>
|
|
<div class="bottomlang">
|
|
<p><span>Available Languages: </span><a href="../en/rewrite/rewrite_guide.html" title="English"> en </a> |
|
|
<a href="../fr/rewrite/rewrite_guide.html" hreflang="fr" rel="alternate" title="Français"> fr </a></p>
|
|
</div><div id="footer">
|
|
<p class="apache">Copyright 2009 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="../faq/">FAQ</a> | <a href="../glossary.html">Glossary</a> | <a href="../sitemap.html">Sitemap</a></p></div>
|
|
</body></html> |