mod_rewrite.xml revision 6fbd2e53c97ea6976d93e0ac521adabc55e0fb73
013e1ddd21f2142a369c9a9a0eeb6c6a0bc3fcf3patrikj<!DOCTYPE modulesynopsis SYSTEM "/style/modulesynopsis.dtd">
e942c741056732f50da2074b36fe59805d370650slive<?xml-stylesheet type="text/xsl" href="/style/manual.en.xsl"?>
6fbd2e53c97ea6976d93e0ac521adabc55e0fb73nd Copyright 2002-2004 The Apache Software Foundation
d5d794fc2f4cc9ca6d6da17cfa2cdcd8d244bacdnd Licensed under the Apache License, Version 2.0 (the "License");
d5d794fc2f4cc9ca6d6da17cfa2cdcd8d244bacdnd you may not use this file except in compliance with the License.
d5d794fc2f4cc9ca6d6da17cfa2cdcd8d244bacdnd You may obtain a copy of the License at
d5d794fc2f4cc9ca6d6da17cfa2cdcd8d244bacdnd Unless required by applicable law or agreed to in writing, software
d5d794fc2f4cc9ca6d6da17cfa2cdcd8d244bacdnd distributed under the License is distributed on an "AS IS" BASIS,
d5d794fc2f4cc9ca6d6da17cfa2cdcd8d244bacdnd WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
d5d794fc2f4cc9ca6d6da17cfa2cdcd8d244bacdnd See the License for the specific language governing permissions and
d5d794fc2f4cc9ca6d6da17cfa2cdcd8d244bacdnd limitations under the License.
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive<description>Provides a rule-based rewriting engine to rewrite requested
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfsliveURLs on the fly</description>
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive<compatibility>Available in Apache 1.3 and later</compatibility>
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive <blockquote>
97a9a944b5887e91042b019776c41d5dd74557aferikabele <p>``The great thing about mod_rewrite is it gives you
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive all the configurability and flexibility of Sendmail.
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive The downside to mod_rewrite is that it gives you all
97a9a944b5887e91042b019776c41d5dd74557aferikabele the configurability and flexibility of Sendmail.''</p>
97a9a944b5887e91042b019776c41d5dd74557aferikabele <p class="cite">-- <cite>Brian Behlendorf</cite><br />
97a9a944b5887e91042b019776c41d5dd74557aferikabele Apache Group</p>
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive </blockquote>
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive <blockquote>
97a9a944b5887e91042b019776c41d5dd74557aferikabele <p>`` Despite the tons of examples and docs,
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive mod_rewrite is voodoo. Damned cool voodoo, but still
97a9a944b5887e91042b019776c41d5dd74557aferikabele voodoo. ''</p>
97a9a944b5887e91042b019776c41d5dd74557aferikabele bem@news.cmc.net</p>
97a9a944b5887e91042b019776c41d5dd74557aferikabele </blockquote>
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive <p>Welcome to mod_rewrite, the Swiss Army Knife of URL
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive manipulation!</p>
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive <p>This module uses a rule-based rewriting engine (based on a
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive regular-expression parser) to rewrite requested URLs on the
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive fly. It supports an unlimited number of rules and an
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive unlimited number of attached rule conditions for each rule to
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive provide a really flexible and powerful URL manipulation
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive mechanism. The URL manipulations can depend on various tests,
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive for instance server variables, environment variables, HTTP
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive headers, time stamps and even external database lookups in
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive various formats can be used to achieve a really granular URL
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive matching.</p>
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive <p>This module operates on the full URLs (including the
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive path-info part) both in per-server context
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive (<code>.htaccess</code>) and can even generate query-string
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive parts on result. The rewritten result can lead to internal
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive sub-processing, external request redirection or even to an
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive internal proxy throughput.</p>
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive <p>But all this functionality and flexibility has its
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive drawback: complexity. So don't expect to understand this
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive entire module in just one day.</p>
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive <p>This module was invented and originally written in April
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive 1996 and gifted exclusively to the The Apache Group in July 1997
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive href="mailto:rse@engelschall.com"><code>rse@engelschall.com</code></a><br />
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive href="http://www.engelschall.com/"><code>www.engelschall.com</code></a>
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive <p>The internal processing of this module is very complex but
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive needs to be explained once even to the average user to avoid
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive common mistakes and to let you exploit its full
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive functionality.</p>
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive <p>First you have to understand that when Apache processes a
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive HTTP request it does this in phases. A hook for each of these
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive phases is provided by the Apache API. Mod_rewrite uses two of
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive these hooks: the URL-to-filename translation hook which is
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive used after the HTTP request has been read but before any
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive authorization starts and the Fixup hook which is triggered
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive after the authorization phases and after the per-directory
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive config files (<code>.htaccess</code>) have been read, but
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive before the content handler is activated.</p>
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive <p>So, after a request comes in and Apache has determined the
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive corresponding server (or virtual server) the rewriting engine
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive starts processing of all mod_rewrite directives from the
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive per-server configuration in the URL-to-filename phase. A few
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive steps later when the final data directories are found, the
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive per-directory configuration directives of mod_rewrite are
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive triggered in the Fixup phase. In both situations mod_rewrite
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive rewrites URLs either to new URLs or to filenames, although
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive there is no obvious distinction between them. This is a usage
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive of the API which was not intended to be this way when the API
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive was designed, but as of Apache 1.x this is the only way
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive mod_rewrite can operate. To make this point more clear
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive remember the following two points:</p>
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive <li>Although mod_rewrite rewrites URLs to URLs, URLs to
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive filenames and even filenames to filenames, the API
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive currently provides only a URL-to-filename hook. In Apache
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive 2.0 the two missing hooks will be added to make the
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive processing more clear. But this point has no drawbacks for
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive the user, it is just a fact which should be remembered:
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive Apache does more in the URL-to-filename hook than the API
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive intends for it.</li>
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive Unbelievably mod_rewrite provides URL manipulations in
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive <code>.htaccess</code> files, although these are reached
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive a very long time after the URLs have been translated to
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive filenames. It has to be this way because
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive <code>.htaccess</code> files live in the filesystem, so
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive processing has already reached this stage. In other
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive words: According to the API phases at this time it is too
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive late for any URL manipulations. To overcome this chicken
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive and egg problem mod_rewrite uses a trick: When you
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive mod_rewrite first rewrites the filename back to its
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive corresponding URL (which is usually impossible, but see
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive trick to achieve this) and then initiates a new internal
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive sub-request with the new URL. This restarts processing of
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive the API phases.
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive <p>Again mod_rewrite tries hard to make this complicated
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive step totally transparent to the user, but you should
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive remember here: While URL manipulations in per-server
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive context are really fast and efficient, per-directory
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive rewrites are slow and inefficient due to this chicken and
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive egg problem. But on the other hand this is the only way
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive mod_rewrite can provide (locally restricted) URL
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive manipulations to the average user.</p>
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive<section id="InternalRuleset"><title>Ruleset Processing</title>
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive <p>Now when mod_rewrite is triggered in these two API phases, it
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive reads the configured rulesets from its configuration
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive structure (which itself was either created on startup for
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive per-server context or during the directory walk of the Apache
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive kernel for per-directory context). Then the URL rewriting
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive engine is started with the contained ruleset (one or more
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive rules together with their conditions). The operation of the
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive URL rewriting engine itself is exactly the same for both
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive configuration contexts. Only the final result processing is
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive different. </p>
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive <p>The order of rules in the ruleset is important because the
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive rewriting engine processes them in a special (and not very
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive obvious) order. The rule is this: The rewriting engine loops
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive through the ruleset rule by rule (<directive
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive module="mod_rewrite">RewriteRule</directive> directives) and
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive when a particular rule matches it optionally loops through
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive existing corresponding conditions (<code>RewriteCond</code>
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive directives). For historical reasons the conditions are given
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive first, and so the control flow is a little bit long-winded. See
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive Figure 1 for more details.</p>
97a9a944b5887e91042b019776c41d5dd74557aferikabele <img src="/images/mod_rewrite_fig1.gif" width="428"
97a9a944b5887e91042b019776c41d5dd74557aferikabele height="385" alt="[Needs graphics capability to display]" /><br />
97a9a944b5887e91042b019776c41d5dd74557aferikabele <dfn>Figure 1:</dfn>The control flow through the rewriting ruleset
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive <p>As you can see, first the URL is matched against the
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive <em>Pattern</em> of each rule. When it fails mod_rewrite
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive immediately stops processing this rule and continues with the
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive next rule. If the <em>Pattern</em> matches, mod_rewrite looks
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive for corresponding rule conditions. If none are present, it
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive just substitutes the URL with a new value which is
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive constructed from the string <em>Substitution</em> and goes on
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive with its rule-looping. But if conditions exist, it starts an
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive inner loop for processing them in the order that they are
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive listed. For conditions the logic is different: we don't match
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive a pattern against the current URL. Instead we first create a
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive back-references, map lookups, <em>etc.</em> and then we try
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive to match <em>CondPattern</em> against it. If the pattern
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive doesn't match, the complete set of conditions and the
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive corresponding rule fails. If the pattern matches, then the
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive next condition is processed until no more conditions are
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive available. If all conditions match, processing is continued
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive with the substitution of the URL with
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive<section id="quoting"><title>Quoting Special Characters</title>
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive <p>As of Apache 1.3.20, special characters in
013e1ddd21f2142a369c9a9a0eeb6c6a0bc3fcf3patrikj <em>TestString</em> and <em>Substitution</em> strings can be
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive escaped (that is, treated as normal characters without their
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive usual special meaning) by prefixing them with a slosh ('\')
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive character. In other words, you can include an actual
013e1ddd21f2142a369c9a9a0eeb6c6a0bc3fcf3patrikj dollar-sign character in a <em>Substitution</em> string by
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive using '<code>\$</code>'; this keeps mod_rewrite from trying
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive to treat it as a backreference.</p>
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive<section id="InternalBackRefs"><title>Regex Back-Reference Availability</title>
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive <p>One important thing here has to be remembered: Whenever you
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive <em>CondPattern</em>, back-references are internally created
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive which can be used with the strings <code>$N</code> and
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive <code>%N</code> (see below). These are available for creating
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive the strings <em>Substitution</em> and <em>TestString</em>.
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive Figure 2 shows to which locations the back-references are
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive transfered for expansion.</p>
97a9a944b5887e91042b019776c41d5dd74557aferikabele <img src="/images/mod_rewrite_fig2.gif" width="381"
97a9a944b5887e91042b019776c41d5dd74557aferikabele height="179" alt="[Needs graphics capability to display]" /><br />
97a9a944b5887e91042b019776c41d5dd74557aferikabele <dfn>Figure 2:</dfn> The back-reference flow through a rule.
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive <p>We know this was a crash course on mod_rewrite's internal
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive processing. But you will benefit from this knowledge when
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive reading the following documentation of the available
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive directives.</p>
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive<section id="EnvVar"><title>Environment Variables</title>
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive <p>This module keeps track of two additional (non-standard)
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive CGI/SSI environment variables named <code>SCRIPT_URL</code>
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive <em>logical</em> Web-view to the current resource, while the
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive standard CGI/SSI variables <code>SCRIPT_NAME</code> and
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive <code>SCRIPT_FILENAME</code> contain the <em>physical</em>
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive System-view. </p>
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive <p>Notice: These variables hold the URI/URL <em>as they were
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive initially requested</em>, <em>i.e.</em>, <em>before</em> any
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive rewriting. This is important because the rewriting process is
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive primarily used to rewrite logical URLs to physical
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive pathnames.</p>
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfsliveSCRIPT_NAME=/sw/lib/w3s/tree/global/u/rse/.www/index.html
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive<section id="Solutions"><title>Practical Solutions</title>
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive <p>We also have an <a href="/misc/rewriteguide.html">URL
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive Rewriting Guide</a> available, which provides a collection of
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive practical solutions for URL-based problems. There you can
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive find real-life rulesets and additional information about
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive mod_rewrite.</p>
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive<directivesynopsis>
013e1ddd21f2142a369c9a9a0eeb6c6a0bc3fcf3patrikj<description>Enables or disables runtime rewriting engine</description>
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive<contextlist><context>server config</context><context>virtual host</context>
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive<context>directory</context><context>.htaccess</context></contextlist>
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive <p>The <directive>RewriteEngine</directive> directive enables or
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive disables the runtime rewriting engine. If it is set to
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive <code>off</code> this module does no runtime processing at
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive all. It does not even update the <code>SCRIPT_URx</code>
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive environment variables.</p>
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive <p>Use this directive to disable the module instead of
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive commenting out all the <directive
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive module="mod_rewrite">RewriteRule</directive> directives!</p>
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive <p>Note that, by default, rewrite configurations are not
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive inherited. This means that you need to have a
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive <code>RewriteEngine on</code> directive for each virtual host
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive in which you wish to use it.</p>
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive</directivesynopsis>
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive<directivesynopsis>
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive<description>Sets some special options for the rewrite engine</description>
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive<contextlist><context>server config</context><context>virtual host</context>
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive<context>directory</context><context>.htaccess</context></contextlist>
1f8adbbac16c6f448602d983ada05574b33888b6nd<compatibility><code>MaxRedirects</code> is available in Apache 2.0.45 and
9ed9ba1fcf0a4a39f78f5f809c661bbd590b70eandlater</compatibility>
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive <p>The <directive>RewriteOptions</directive> directive sets some
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive special options for the current per-server or per-directory
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive configuration. The <em>Option</em> strings can be one of the
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive following:</p>
9ed9ba1fcf0a4a39f78f5f809c661bbd590b70eand <dd>This forces the current configuration to inherit the
9ed9ba1fcf0a4a39f78f5f809c661bbd590b70eand configuration of the parent. In per-virtual-server context
9ed9ba1fcf0a4a39f78f5f809c661bbd590b70eand this means that the maps, conditions and rules of the main
9ed9ba1fcf0a4a39f78f5f809c661bbd590b70eand server are inherited. In per-directory context this means
9ed9ba1fcf0a4a39f78f5f809c661bbd590b70eand that conditions and rules of the parent directory's
9ed9ba1fcf0a4a39f78f5f809c661bbd590b70eand <dd>In order to prevent endless loops of internal redirects
9ed9ba1fcf0a4a39f78f5f809c661bbd590b70eand >RewriteRule</directive>s, <module>mod_rewrite</module> aborts
9ed9ba1fcf0a4a39f78f5f809c661bbd590b70eand the request after reaching a maximum number of such redirects and
9ed9ba1fcf0a4a39f78f5f809c661bbd590b70eand responds with an 500 Internal Server Error. If you really need
9ed9ba1fcf0a4a39f78f5f809c661bbd590b70eand more internal redirects than 10 per request, you may increase
9ed9ba1fcf0a4a39f78f5f809c661bbd590b70eand the default to the desired value.</dd>
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive</directivesynopsis>
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive<directivesynopsis>
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive<description>Sets the name of the file used for logging rewrite engine
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfsliveprocessing</description>
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive<contextlist><context>server config</context><context>virtual host</context>
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive</contextlist>
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive <p>The <directive>RewriteLog</directive> directive sets the name
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive of the file to which the server logs any rewriting actions it
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive performs. If the name does not begin with a slash
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive ('<code>/</code>') then it is assumed to be relative to the
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive <em>Server Root</em>. The directive should occur only once per
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive server config.</p>
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive<note> To disable the logging of
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive rewriting actions it is not recommended to set
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive although the rewriting engine does not then output to a
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive logfile it still creates the logfile output internally.
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive <strong>This will slow down the server with no advantage
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive to the administrator!</strong> To disable logging either
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive remove or comment out the <directive>RewriteLog</directive>
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfsliveSee the <a href="/misc/security_tips.html">Apache Security Tips</a>
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslivedocument for details on why your security could be compromised if the
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslivedirectory where logfiles are stored is writable by anyone other than
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslivethe user that starts the server.
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive</directivesynopsis>
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive<directivesynopsis>
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive<description>Sets the verbosity of the log file used by the rewrite
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfsliveengine</description>
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive<contextlist><context>server config</context><context>virtual host</context>
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive</contextlist>
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive <p>The <directive>RewriteLogLevel</directive> directive sets the
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive verbosity level of the rewriting logfile. The default level 0
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive means no logging, while 9 or more means that practically all
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive actions are logged.</p>
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive <p>To disable the logging of rewriting actions simply set
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive<note> Using a high value for
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive dramatically! Use the rewriting logfile at a
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfsliveRewriteLogLevel 3
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive</directivesynopsis>
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive<directivesynopsis>
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive<description>Sets the name of the lock file used for <directive
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslivesynchronization</description>
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive<contextlist><context>server config</context></contextlist>
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive <p>This directive sets the filename for a synchronization
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive lockfile which mod_rewrite needs to communicate with <directive
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive <em>programs</em>. Set this lockfile to a local path (not on a
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive NFS-mounted device) when you want to use a rewriting
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive map-program. It is not required for other types of rewriting
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive</directivesynopsis>
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive<directivesynopsis>
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive<description>Defines a mapping function for key-lookup</description>
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive<syntax>RewriteMap <em>MapName</em> <em>MapType</em>:<em>MapSource</em>
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive<contextlist><context>server config</context><context>virtual host</context>
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive</contextlist>
630c456b6461158be6cc5c5483735e27b13b4ad5nd<compatibility>The choice of different dbm types is available in
630c456b6461158be6cc5c5483735e27b13b4ad5ndApache 2.0.41 and later</compatibility>
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive <p>The <directive>RewriteMap</directive> directive defines a
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive substitution strings by the mapping-functions to
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive insert/substitute fields through a key lookup. The source of
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive this lookup can be of various types.</p>
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive <p>The <a id="mapfunc" name="mapfunc"><em>MapName</em></a> is
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive the name of the map and will be used to specify a
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive mapping-function for the substitution strings of a rewriting
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive rule via one of the following constructs:</p>
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive <strong><code>${</code> <em>MapName</em> <code>:</code>
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive <em>LookupKey</em> <code>|</code> <em>DefaultValue</em>
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive <p>When such a construct occurs the map <em>MapName</em> is
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive consulted and the key <em>LookupKey</em> is looked-up. If the
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive key is found, the map-function construct is substituted by
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive <em>SubstValue</em>. If the key is not found then it is
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive substituted by <em>DefaultValue</em> or by the empty string
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive <p>The following combinations for <em>MapType</em> and
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive path to valid regular file
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive <p>This is the standard rewriting map feature where the
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive either blank lines, comment lines (starting with a '#'
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive character) or pairs like the following - one per
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive## map.txt -- rewriting map
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfsliveRalf.S.Engelschall rse # Bastard Operator From Hell
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfsliveMr.Joe.Average joe # Mr. Average
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive path to valid regular file
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive <p>This is identical to the Standard Plain Text variant
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive above but with a special post-processing feature: After
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive looking up a value it is parsed according to contained
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive ``<code>|</code>'' characters which have the meaning of
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive ``or''. In other words they indicate a set of
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive alternatives from which the actual returned value is
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive chosen randomly. Although this sounds crazy and useless,
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive it was actually designed for load balancing in a reverse
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive proxy situation where the looked up values are server
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive names. Example:</p>
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive## map.txt -- rewriting map
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslivestatic www1|www2|www3|www4
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslivedynamic www5|www6
1578daeec017d3bb20cecdcdc3b0261c999730d5slive <code>dbm[=<em>type</em>]</code>, MapSource: Unix filesystem
1578daeec017d3bb20cecdcdc3b0261c999730d5slive path to valid regular file
1578daeec017d3bb20cecdcdc3b0261c999730d5slive <p>Here the source is a binary format DBM file containing
1578daeec017d3bb20cecdcdc3b0261c999730d5slive the same contents as a <em>Plain Text</em> format file, but
1578daeec017d3bb20cecdcdc3b0261c999730d5slive in a special representation which is optimized for really
1578daeec017d3bb20cecdcdc3b0261c999730d5slive fast lookups. The <em>type</em> can be sdbm, gdbm, ndbm, or
1578daeec017d3bb20cecdcdc3b0261c999730d5slive db depending on <a href="/install.html#dbm">compile-time
1578daeec017d3bb20cecdcdc3b0261c999730d5slive compile-time default will be chosen. You can create such a
1578daeec017d3bb20cecdcdc3b0261c999730d5slive file with any DBM tool or with the following Perl
1578daeec017d3bb20cecdcdc3b0261c999730d5slive script. Be sure to adjust it to create the appropriate
1578daeec017d3bb20cecdcdc3b0261c999730d5slive type of DBM. The example creates an NDBM file.</p>
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive## txt2dbm -- convert txt map to dbm format
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfsliveuse NDBM_File;
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive($txtmap, $dbmmap) = @ARGV;
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfsliveopen(TXT, "<$txtmap") or die "Couldn't open $txtmap!\n";
97a9a944b5887e91042b019776c41d5dd74557aferikabeletie (%DB, 'NDBM_File', $dbmmap,O_RDWR|O_TRUNC|O_CREAT, 0644)
97a9a944b5887e91042b019776c41d5dd74557aferikabele or die "Couldn't create $dbmmap!\n";
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslivewhile (<TXT>) {
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive next if (/^\s*#/ or /^\s*$/);
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive $DB{$1} = $2 if (/^\s*(\S+)\s+(\S+)/);
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive <p>Here the source is an internal Apache function.
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive Currently you cannot create your own, but the following
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive functions already exists:</p>
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive Converts the looked up key to all upper case.</li>
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive Converts the looked up key to all lower case.</li>
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive Translates special characters in the looked up key to
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive hex-encodings.</li>
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive Translates hex-encodings in the looked up key back to
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive special characters.</li>
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive path to valid regular file
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive <p>Here the source is a program, not a map file. To
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive create it you can use the language of your choice, but
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive the result has to be a executable (<em>i.e.</em>, either
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive object-code or a script with the magic cookie trick
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive <p>This program is started once at startup of the Apache
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive servers and then communicates with the rewriting engine
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive file-handles. For each map-function lookup it will
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive receive the key to lookup as a newline-terminated string
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive looked-up value as a newline-terminated string on
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive ``<code>NULL</code>'' if it fails (<em>i.e.</em>, there
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive is no corresponding value for the given key). A trivial
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive program which will implement a 1:1 map (<em>i.e.</em>,
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive key == value) could be:</p>
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslivewhile (<STDIN>) {
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive # ...put here any transformations or lookups...
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive <li>``<em>Keep it simple, stupid</em>'' (KISS), because
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive if this program hangs it will hang the Apache server
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive when the rule occurs.</li>
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive <li>Avoid one common mistake: never do buffered I/O on
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive <code>stdout</code>! This will cause a deadloop! Hence
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive the ``<code>$|=1</code>'' in the above example...</li>
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive module="mod_rewrite">RewriteLock</directive> directive to
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive define a lockfile mod_rewrite can use to synchronize the
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive communication to the program. By default no such
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive synchronization takes place.</li>
013e1ddd21f2142a369c9a9a0eeb6c6a0bc3fcf3patrikj <p>The <directive>RewriteMap</directive> directive can occur more than
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive once. For each mapping-function use one
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive <directive>RewriteMap</directive> directive to declare its rewriting
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive mapfile. While you cannot <strong>declare</strong> a map in
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive per-directory context it is of course possible to
013e1ddd21f2142a369c9a9a0eeb6c6a0bc3fcf3patrikj <strong>use</strong> this map in per-directory context. </p>
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive<note><title>Note</title> For plain text and DBM format files the
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslivelooked-up keys are cached in-core until the <code>mtime</code> of the
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslivemapfile changes or the server does a restart. This way you can have
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslivemap-functions in rules which are used for <strong>every</strong>
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfsliverequest. This is no problem, because the external lookup only happens
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive</directivesynopsis>
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive<directivesynopsis>
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive<description>Sets the base URL for per-directory rewrites</description>
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive<contextlist><context>directory</context><context>.htaccess</context>
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive</contextlist>
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive <p>The <directive>RewriteBase</directive> directive explicitly
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive sets the base URL for per-directory rewrites. As you will see
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive below, <directive module="mod_rewrite">RewriteRule</directive>
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive can be used in per-directory config files
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive <em>i.e.</em>, the local directory prefix is stripped at this
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive stage of processing and your rewriting rules act only on the
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive remainder. At the end it is automatically added back to the
013e1ddd21f2142a369c9a9a0eeb6c6a0bc3fcf3patrikj path. The default setting is; <directive>RewriteBase</directive> <em>physical-directory-path</em></p>
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive <p>When a substitution occurs for a new URL, this module has
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive to re-inject the URL into the server processing. To be able
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive to do this it needs to know what the corresponding URL-prefix
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive or URL-base is. By default this prefix is the corresponding
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive filepath itself. <strong>But at most websites URLs are NOT
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive directly related to physical filename paths, so this
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive assumption will usually be wrong!</strong> There you have to
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive use the <code>RewriteBase</code> directive to specify the
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive correct URL-prefix.</p>
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive<note> If your webserver's URLs are <strong>not</strong> directly
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfsliverelated to physical file paths, you have to use
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive<directive>RewriteBase</directive> in every <code>.htaccess</code>
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslivefiles where you want to use <directive
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslivemodule="mod_rewrite">RewriteRule</directive> directives.
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive <p> For example, assume the following per-directory config file:</p>
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive# /abc/def/.htaccess -- per-dir config file for directory /abc/def
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive# Remember: /abc/def is the physical path of /xyz, <em>i.e.</em>, the server
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfsliveRewriteEngine On
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive# let the server know that we were reached via /xyz and not
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfsliveRewriteBase /xyz
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive# now the rewriting rules
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfsliveRewriteRule ^oldstuff\.html$ newstuff.html
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive <p>In the above example, a request to
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive <code>/xyz/oldstuff.html</code> gets correctly rewritten to
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive the physical file <code>/abc/def/newstuff.html</code>.</p>
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive<p>The following list gives detailed information about
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive the internal processing steps:</p>
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfsliveInternal Processing:
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive /xyz/oldstuff.html -> /abc/def/oldstuff.html (per-server Alias)
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive /abc/def/oldstuff.html -> /abc/def/newstuff.html (per-dir RewriteRule)
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive /abc/def/newstuff.html -> /xyz/newstuff.html (per-dir RewriteBase)
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive /xyz/newstuff.html -> /abc/def/newstuff.html (per-server Alias)
013e1ddd21f2142a369c9a9a0eeb6c6a0bc3fcf3patrikj <p>This seems very complicated but is
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive the correct Apache internal processing, because the
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive per-directory rewriting comes too late in the
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive process. So, when it occurs the (rewritten) request
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive has to be re-injected into the Apache kernel! BUT:
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive While this seems like a serious overhead, it really
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive isn't, because this re-injection happens fully
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive internally to the Apache server and the same
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive procedure is used by many other operations inside
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive Apache. So, you can be sure the design and
013e1ddd21f2142a369c9a9a0eeb6c6a0bc3fcf3patrikj implementation is correct.</p>
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive</directivesynopsis>
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive<directivesynopsis>
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive<description>Defines a condition under which rewriting will take place
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive</description>
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive<syntax> RewriteCond
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive<contextlist><context>server config</context><context>virtual host</context>
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive<context>directory</context><context>.htaccess</context></contextlist>
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive <p>The <directive>RewriteCond</directive> directive defines a
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive rule condition. Precede a <directive
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive module="mod_rewrite">RewriteRule</directive> directive with one
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive or more <directive>RewriteCond</directive> directives. The following
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive rewriting rule is only used if its pattern matches the current
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive state of the URI <strong>and</strong> if these additional
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive conditions apply too.</p>
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive <p><em>TestString</em> is a string which can contains the
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive following expanded constructs in addition to plain text:</p>
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive <strong>RewriteRule backreferences</strong>: These are
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive backreferences of the form
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive (0 <= N <= 9) which provide access to the grouped
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive parts (parenthesis!) of the pattern from the
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive corresponding <code>RewriteRule</code> directive (the one
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive following the current bunch of <code>RewriteCond</code>
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive directives).
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive <strong>RewriteCond backreferences</strong>: These are
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive backreferences of the form
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive (1 <= N <= 9) which provide access to the grouped
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive parts (parentheses!) of the pattern from the last matched
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive <code>RewriteCond</code> directive in the current bunch
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive of conditions.
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive expansions of the form
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive RewriteMap</a> for more details.
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive <strong>Server-Variables</strong>: These are variables of
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive from the following list:
97a9a944b5887e91042b019776c41d5dd74557aferikabele <th>HTTP headers:</th> <th>connection & request:</th> <th></th>
97a9a944b5887e91042b019776c41d5dd74557aferikabele HTTP_USER_AGENT<br />
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive HTTP_REFERER<br />
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive HTTP_COOKIE<br />
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive HTTP_FORWARDED<br />
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive HTTP_HOST<br />
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive HTTP_PROXY_CONNECTION<br />
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive HTTP_ACCEPT<br />
97a9a944b5887e91042b019776c41d5dd74557aferikabele REMOTE_ADDR<br />
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive REMOTE_HOST<br />
74a6de79356cd15d2e47065087785e36dd65aa41nd REMOTE_PORT<br />
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive REMOTE_USER<br />
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive REMOTE_IDENT<br />
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive REQUEST_METHOD<br />
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive SCRIPT_FILENAME<br />
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive PATH_INFO<br />
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive QUERY_STRING<br />
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive AUTH_TYPE<br />
97a9a944b5887e91042b019776c41d5dd74557aferikabele <th>server internals:</th> <th>system stuff:</th> <th>specials:</th>
97a9a944b5887e91042b019776c41d5dd74557aferikabele DOCUMENT_ROOT<br />
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive SERVER_ADMIN<br />
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive SERVER_NAME<br />
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive SERVER_ADDR<br />
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive SERVER_PORT<br />
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive SERVER_PROTOCOL<br />
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive SERVER_SOFTWARE<br />
97a9a944b5887e91042b019776c41d5dd74557aferikabele TIME_YEAR<br />
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive TIME_MON<br />
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive TIME_DAY<br />
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive TIME_HOUR<br />
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive TIME_MIN<br />
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive TIME_SEC<br />
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive TIME_WDAY<br />
97a9a944b5887e91042b019776c41d5dd74557aferikabele API_VERSION<br />
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive THE_REQUEST<br />
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive REQUEST_URI<br />
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive REQUEST_FILENAME<br />
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive IS_SUBREQ<br />
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive <p>These variables all
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive correspond to the similarly named HTTP
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive MIME-headers, C variables of the Apache server or
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive Most are documented elsewhere in the Manual or in
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive the CGI specification. Those that are special to
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive mod_rewrite include:</p>
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive <dd>Will contain the text "true" if the request
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive currently being processed is a sub-request,
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive "false" otherwise. Sub-requests may be generated
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive by modules that need to resolve additional files
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive or URIs in order to complete their tasks.</dd>
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive <dd>This is the version of the Apache module API
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive (the internal interface between server and
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive module) in the current httpd build, as defined in
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive corresponds to the version of Apache in use (in
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive the release version of Apache 1.3.14, for
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive instance, it is 19990320:10), but is mainly of
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive interest to module authors.</dd>
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive <dd>The full HTTP request line sent by the
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive include any additional headers sent by the
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive browser.</dd>
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive <dd>The resource requested in the HTTP request
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive line. (In the example above, this would be
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive <dd>The full local filesystem path to the file or
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive script matching the request.</dd>
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive <li>The variables SCRIPT_FILENAME and REQUEST_FILENAME
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive contain the same value, <em>i.e.</em>, the value of the
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive <code>request_rec</code> structure of the Apache server.
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive The first name is just the commonly known CGI variable name
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive while the second is the consistent counterpart to
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive REQUEST_URI (which contains the value of the
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive <code>uri</code> field of <code>request_rec</code>).</li>
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive <li>There is the special format:
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive <code>%{ENV:variable}</code> where <em>variable</em> can be
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive any environment variable. This is looked-up via internal
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive Apache structures and (if not found there) via
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive <code>getenv()</code> from the Apache server process.</li>
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive <li>There is the special format:
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive <code>%{HTTP:header}</code> where <em>header</em> can be
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive any HTTP MIME-header name. This is looked-up from the HTTP
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive request. Example: <code>%{HTTP:Proxy-Connection}</code> is
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive the value of the HTTP header
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive <li>There is the special format
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive <code>%{LA-U:variable}</code> for look-aheads which perform
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive an internal (URL-based) sub-request to determine the final
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive value of <em>variable</em>. Use this when you want to use a
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive variable for rewriting which is actually set later in an
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive API phase and thus is not available at the current stage.
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive For instance when you want to rewrite according to the
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive per-server context (<code>httpd.conf</code> file) you have
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive variable is set by the authorization phases which come
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive <em>after</em> the URL translation phase where mod_rewrite
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive operates. On the other hand, because mod_rewrite implements
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive its per-directory context (<code>.htaccess</code> file) via
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive the Fixup phase of the API and because the authorization
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive phases come <em>before</em> this phase, you just can use
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive <li>There is the special format:
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive <code>%{LA-F:variable}</code> which performs an internal
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive (filename-based) sub-request to determine the final value
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive of <em>variable</em>. Most of the time this is the same as
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive LA-U above.</li>
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive <em>i.e.</em>, a regular expression which is applied to the
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive current instance of the <em>TestString</em>, <em>i.e.</em>,
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive <em>TestString</em> is evaluated and then matched against
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive <p><strong>Remember:</strong> <em>CondPattern</em> is a
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive additions:</p>
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive <li>You can prefix the pattern string with a
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive '<code>!</code>' character (exclamation mark) to specify a
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive There are some special variants of <em>CondPatterns</em>.
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive Instead of real regular expression strings you can also
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive use one of the following:
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive lower)<br />
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive greater)<br />
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive equal)<br />
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive equal (character by character). If <em>CondPattern</em>
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive compares <em>TestString</em> to the empty string.</li>
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive Treats the <em>TestString</em> as a pathname and tests
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive if it exists and is a directory.</li>
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive Treats the <em>TestString</em> as a pathname and tests
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive if it exists and is a regular file.</li>
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive Treats the <em>TestString</em> as a pathname and tests
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive if it exists and is a regular file with size greater
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive than zero.</li>
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive Treats the <em>TestString</em> as a pathname and tests
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive if it exists and is a symbolic link.</li>
4e3cdb85620921a8a120fe22edbccae708f4f34end <li>'<strong>-x</strong>' (has e<strong>x</strong>ecutable
4e3cdb85620921a8a120fe22edbccae708f4f34end permissions)<br />
4e3cdb85620921a8a120fe22edbccae708f4f34end if it exists and has execution permissions. These permissions
4e3cdb85620921a8a120fe22edbccae708f4f34end are determined depending on the underlying OS.</li>
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive subrequest)<br />
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive accessible via all the server's currently-configured
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive access controls for that path. This uses an internal
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive subrequest to determine the check, so use it with care
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive because it decreases your servers performance!</li>
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive subrequest)<br />
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive accessible via all the server's currently-configured
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive access controls for that path. This uses an internal
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive subrequest to determine the check, so use it with care
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive because it decreases your server's performance!</li>
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive All of these tests can
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive also be prefixed by an exclamation mark ('!') to
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive negate their meaning.
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive <p>Additionally you can set special flags for
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive <strong><code>[</code><em>flags</em><code>]</code></strong>
013e1ddd21f2142a369c9a9a0eeb6c6a0bc3fcf3patrikj <p>as the third argument to the <code>RewriteCond</code>
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive directive. <em>Flags</em> is a comma-separated list of the
013e1ddd21f2142a369c9a9a0eeb6c6a0bc3fcf3patrikj following flags:</p>
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive This makes the test case-insensitive, <em>i.e.</em>, there
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive is no difference between 'A-Z' and 'a-z' both in the
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive expanded <em>TestString</em> and the <em>CondPattern</em>.
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive This flag is effective only for comparisons between
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive <em>TestString</em> and <em>CondPattern</em>. It has no
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive effect on filesystem and subrequest checks.</li>
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive Use this to combine rule conditions with a local OR
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive instead of the implicit AND. Typical example:
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfsliveRewriteCond %{REMOTE_HOST} ^host1.* [OR]
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfsliveRewriteCond %{REMOTE_HOST} ^host2.* [OR]
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfsliveRewriteCond %{REMOTE_HOST} ^host3.*
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfsliveRewriteRule ...some special stuff for any of these hosts...
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive Without this flag you would have to write the cond/rule
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive three times.
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive <p>To rewrite the Homepage of a site according to the
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive ``<code>User-Agent:</code>'' header of the request, you can
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive use the following: </p>
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfsliveRewriteCond %{HTTP_USER_AGENT} ^Mozilla.*
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfsliveRewriteRule ^/$ /homepage.max.html [L]
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfsliveRewriteCond %{HTTP_USER_AGENT} ^Lynx.*
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfsliveRewriteRule ^/$ /homepage.min.html [L]
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfsliveRewriteRule ^/$ /homepage.std.html [L]
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive <p>Interpretation: If you use Netscape Navigator as your
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive browser (which identifies itself as 'Mozilla'), then you
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive get the max homepage, which includes Frames, <em>etc.</em>
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive If you use the Lynx browser (which is Terminal-based), then
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive you get the min homepage, which contains no images, no
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive tables, <em>etc.</em> If you use any other browser you get
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive the standard homepage.</p>
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive</directivesynopsis>
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive<directivesynopsis>
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive<description>Defines rules for the rewriting engine</description>
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive<syntax>RewriteRule
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive<contextlist><context>server config</context><context>virtual host</context>
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive<context>directory</context><context>.htaccess</context></contextlist>
630c456b6461158be6cc5c5483735e27b13b4ad5nd<compatibility>The cookie-flag is available in Apache 2.0.40 and later.</compatibility>
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive <p>The <directive>RewriteRule</directive> directive is the real
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive rewriting workhorse. The directive can occur more than once.
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive Each directive then defines one single rewriting rule. The
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive <strong>important</strong>, because this order is used when
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive applying the rules at run-time.</p>
630c456b6461158be6cc5c5483735e27b13b4ad5nd <p><a id="patterns" name="patterns"><em>Pattern</em></a> is
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive expression</a> which gets applied to the current URL. Here
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive ``current'' means the value of the URL when this rule gets
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive applied. This may not be the originally requested URL,
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive because any number of rules may already have matched and made
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive alterations to it.</p>
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive <p>Some hints about the syntax of regular expressions:</p>
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive <strong><code>[</code></strong>chars<strong><code>]</code></strong> Character class: One of chars
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive <strong><code>[^</code></strong>chars<strong><code>]</code></strong> Character class: None of chars
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive text1<strong><code>|</code></strong>text2 Alternative: text1 or text2
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive <strong><code>?</code></strong> 0 or 1 of the preceding text
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive <strong><code>*</code></strong> 0 or N of the preceding text (N > 0)
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive <strong><code>+</code></strong> 1 or N of the preceding text (N > 1)
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive <strong><code>(</code></strong>text<strong><code>)</code></strong> Grouping of text
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive (either to set the borders of an alternative or
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive for making backreferences where the <strong>N</strong>th group can
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive be used on the RHS of a RewriteRule with <code>$</code><strong>N</strong>)
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive <strong><code>\</code></strong>char escape that particular char
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive (for instance to specify the chars "<code>.[]()</code>" <em>etc.</em>)
630c456b6461158be6cc5c5483735e27b13b4ad5nd <p>For more information about regular expressions have a look at the
630c456b6461158be6cc5c5483735e27b13b4ad5nd perl regular expression manpage ("<a
630c456b6461158be6cc5c5483735e27b13b4ad5nd href="http://www.perldoc.com/perl5.6.1/pod/perlre.html">perldoc
630c456b6461158be6cc5c5483735e27b13b4ad5nd perlre</a>"). If you are interested in more detailed
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive information about regular expressions and their variants
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive following dedicated book on this topic:</p>
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive Nutshell Handbook Series<br />
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive O'Reilly & Associates, Inc. 1997<br />
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive ISBN 1-56592-257-3<br />
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive <p>Additionally in mod_rewrite the NOT character
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive ('<code>!</code>') is a possible pattern prefix. This gives
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive you the ability to negate a pattern; to say, for instance:
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive ``<em>if the current URL does <strong>NOT</strong> match this
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive pattern</em>''. This can be used for exceptional cases, where
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive it is easier to match the negative pattern, or as a last
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive default rule.</p>
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfsliveWhen using the NOT character
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive to negate a pattern you cannot have grouped wildcard
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive parts in the pattern. This is impossible because when the
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive pattern does NOT match, there are no contents for the
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive groups. In consequence, if negated patterns are used, you
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive <p><a id="rhs" name="rhs"><em>Substitution</em></a> of a
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive rewriting rule is the string which is substituted for (or
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive matched. Beside plain text you can use</p>
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive <li>back-references <code>$N</code> to the RewriteRule
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive pattern</li>
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive <li>back-references <code>%N</code> to the last matched
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive RewriteCond pattern</li>
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive <li>server-variables as in rule condition test-strings
013e1ddd21f2142a369c9a9a0eeb6c6a0bc3fcf3patrikj <p>Back-references are <code>$</code><strong>N</strong>
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive (<strong>N</strong>=0..9) identifiers which will be replaced
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive by the contents of the <strong>N</strong>th group of the
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive matched <em>Pattern</em>. The server-variables are the same
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive as for the <em>TestString</em> of a <code>RewriteCond</code>
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive directive. The mapping-functions come from the
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive <code>RewriteMap</code> directive and are explained there.
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive These three types of variables are expanded in the order of
013e1ddd21f2142a369c9a9a0eeb6c6a0bc3fcf3patrikj the above list. </p>
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive <p>As already mentioned above, all the rewriting rules are
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive definition in the config file). The URL is <strong>completely
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive replaced</strong> by the <em>Substitution</em> and the
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive rewriting process goes on until there are no more rules
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive unless explicitly terminated by a
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive <p>There is a special substitution string named
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive substitution</strong>! Sounds silly? No, it is useful to
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive provide rewriting rules which <strong>only</strong> match
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive conjunction with the <strong>C</strong> (chain) flag to be
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive able to have more than one pattern to be applied before a
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive substitution occurs.</p>
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive <p>One more note: You can even create URLs in the
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive substitution string containing a query string part. Just use
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive a question mark inside the substitution string to indicate
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive that the following stuff should be re-injected into the
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive QUERY_STRING. When you want to erase an existing query
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive string, end the substitution string with just the question
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfsliveThere is a special feature:
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive When you prefix a substitution field with
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive <code>http://</code><em>thishost</em>[<em>:thisport</em>]
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive then <strong>mod_rewrite</strong> automatically strips it
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive out. This auto-reduction on implicit external redirect
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive URLs is a useful and important feature when used in
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive combination with a mapping-function which generates the
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive hostname part. Have a look at the first example in the
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive example section below to understand this.
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive An unconditional external
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive redirect to your own server will not work with the prefix
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive <code>http://thishost</code> because of this feature. To
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive achieve such a self-redirect, you have to use the
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive <p>Additionally you can set special flags for
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive <strong><code>[</code><em>flags</em><code>]</code></strong>
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive directive. <em>Flags</em> is a comma-separated list of the
013e1ddd21f2142a369c9a9a0eeb6c6a0bc3fcf3patrikj following flags: </p>
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive <code>http://thishost[:thisport]/</code> (which makes the
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive new URL a URI) to force a external redirection. If no
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive TEMPORARILY) is used. If you want to use other response
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive codes in the range 300-400 just specify them as a number
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive or use one of the following symbolic names:
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive canonicalize the URL and give it back to the client,
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive <p><strong>Note:</strong> When you use this flag, make
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive sure that the substitution field is a valid URL! If not,
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive you are redirecting to an invalid location! And remember
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive that this flag itself only prefixes the URL with
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive continues. Usually you also want to stop and do the
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive redirection immediately. To stop the rewriting you also
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive have to provide the 'L' flag.</p>
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive <li>'<strong><code>forbidden|F</code></strong>' (force URL
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive This forces the current URL to be forbidden,
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive <em>i.e.</em>, it immediately sends back a HTTP response of
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive 403 (FORBIDDEN). Use this flag in conjunction with
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive appropriate RewriteConds to conditionally block some
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive <li>'<strong><code>gone|G</code></strong>' (force URL to be
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive This forces the current URL to be gone, <em>i.e.</em>, it
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive immediately sends back a HTTP response of 410 (GONE). Use
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive this flag to mark pages which no longer exist as gone.</li>
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive This flag forces the substitution part to be internally
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive forced as a proxy request and immediately (<em>i.e.</em>,
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive rewriting rule processing stops here) put through the <a
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive href="mod_proxy.html">proxy module</a>. You have to make
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive sure that the substitution string is a valid URI
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive handled by the Apache proxy module. If not you get an
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive error from the proxy module. Use this flag to achieve a
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive more powerful implementation of the <a
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive href="mod_proxy.html#proxypass">ProxyPass</a> directive,
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive to map some remote stuff into the namespace of the local
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive <p>Notice: To use this functionality make sure you have
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive the proxy module compiled into your Apache server
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive program. If you don't know please check whether
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive -l</code>'' output. If yes, this functionality is
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive available to mod_rewrite. If not, then you first have to
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive rebuild the ``<code>httpd</code>'' program with mod_proxy
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive enabled.</p>
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive Stop the rewriting process here and don't apply any more
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive rewriting rules. This corresponds to the Perl
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive <code>last</code> command or the <code>break</code> command
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive from the C language. Use this flag to prevent the currently
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive rewritten URL from being rewritten further by following
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive rules. For example, use it to rewrite the root-path URL
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive Re-run the rewriting process (starting again with the
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive first rewriting rule). Here the URL to match is again not
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive the original URL but the URL from the last rewriting rule.
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive This corresponds to the Perl <code>next</code> command or
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive the <code>continue</code> command from the C language. Use
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive this flag to restart the rewriting process, <em>i.e.</em>,
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive to immediately go to the top of the loop.<br />
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive <strong>But be careful not to create an infinite
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive This flag chains the current rule with the next rule
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive (which itself can be chained with the following rule,
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive <em>etc.</em>). This has the following effect: if a rule
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive matches, then processing continues as usual, <em>i.e.</em>,
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive the flag has no effect. If the rule does
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive <strong>not</strong> match, then all following chained
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive rules are skipped. For instance, use it to remove the
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive ``<code>.www</code>'' part inside a per-directory rule set
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive when you let an external redirect happen (where the
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive ``<code>.www</code>'' part should not to occur!).</li>
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive '<strong><code>type|T</code></strong>=<em>MIME-type</em>'
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive Force the MIME-type of the target file to be
1c4127f51c434f3083709d905b02f5d211d746b4nd setup the content-type based on some conditions.
1c4127f51c434f3083709d905b02f5d211d746b4nd For example, the following snippet allows <code>.php</code> files to
1c4127f51c434f3083709d905b02f5d211d746b4nd be <em>displayed</em> by <code>mod_php</code> if they are called with
1c4127f51c434f3083709d905b02f5d211d746b4nd RewriteRule ^(.+\.php)s$ $1 [T=application/x-httpd-php-source]
1c4127f51c434f3083709d905b02f5d211d746b4nd </example>
1c4127f51c434f3083709d905b02f5d211d746b4nd '<strong><code>handler|H</code></strong>=<em>Content-handler</em>'
1c4127f51c434f3083709d905b02f5d211d746b4nd Force the Content-handler of the target file to be
1c4127f51c434f3083709d905b02f5d211d746b4nd <em>Content-handler</em>. For instance, this can be used to
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive <code>ScriptAlias</code> which internally forces all files
1c4127f51c434f3083709d905b02f5d211d746b4nd inside the mapped directory to have a handler of
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive '<strong><code>nosubreq|NS</code></strong>' (used only if
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive This flag forces the rewriting engine to skip a
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive rewriting rule if the current request is an internal
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive sub-request. For instance, sub-requests occur internally
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive in Apache when <code>mod_include</code> tries to find out
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive information about possible directory default files
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive always useful and even sometimes causes a failure to if
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive the complete set of rules are applied. Use this flag to
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive exclude some rules.<br />
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive <p>Use the following rule for your decision: whenever you
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive prefix some URLs with CGI-scripts to force them to be
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive processed by the CGI-script, the chance is high that you
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive will run into problems (or even overhead) on
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive sub-requests. In these cases, use this flag.</p>
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive <em>i.e.</em>, there is no difference between 'A-Z' and
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive 'a-z' when <em>Pattern</em> is matched against the current
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive This flag forces the rewriting engine to append a query
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive string part in the substitution string to the existing one
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive instead of replacing it. Use this when you want to add more
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive data to the query string via a rewrite rule.</li>
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive output)<br />
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive This flag keeps mod_rewrite from applying the usual URI
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive escaping rules to the result of a rewrite. Ordinarily,
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive special characters (such as '%', '$', ';', and so on)
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive will be escaped into their hexcode equivalents ('%25',
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive '%24', and '%3B', respectively); this flag prevents this
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive from being done. This allows percent symbols to appear in
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive the output, as in
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive RewriteRule /foo/(.*) /bar?arg=P1\%3d$1 [R,NE]
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive (<strong>p</strong>ass <strong>t</strong>hrough to next
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive handler)<br />
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive This flag forces the rewriting engine to set the
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive <code>request_rec</code> structure to the value of the
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive <code>filename</code> field. This flag is just a hack to
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive be able to post-process the output of
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive other URI-to-filename translators. A trivial example to
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive show the semantics: If you want to rewrite
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive <code>/abc</code> to <code>/def</code> via the rewriting
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive RewriteRule ^/abc(.*) /def$1 [PT]<br />
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive Alias /def /ghi
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive <em>i.e.</em>, it rewrites <code>uri=/abc/...</code> to
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive <code>filename=/def/...</code> as a full API-compliant
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive URI-to-filename translator should do. Then
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive URI-to-filename transition which will not work.
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive <p>Note: <strong>You have to use this flag if you want to
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive intermix directives of different modules which contain
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive URL-to-filename translators</strong>. The typical example
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive <li>'<strong><code>skip|S</code></strong>=<em>num</em>'
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive This flag forces the rewriting engine to skip the next
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive matches. Use this to make pseudo if-then-else constructs:
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive The last rule of the then-clause becomes
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive <code>skip=N</code> where N is the number of rules in the
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive else-clause. (This is <strong>not</strong> the same as the
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive 'chain|C' flag!)</li>
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive '<strong><code>env|E=</code></strong><em>VAR</em>:<em>VAL</em>'
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive This forces an environment variable named <em>VAR</em> to
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive be set to the value <em>VAL</em>, where <em>VAL</em> can
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive <code>%N</code> which will be expanded. You can use this
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive flag more than once to set more than one variable. The
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive variables can be later dereferenced in many situations, but
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive usually from within XSSI (via <code><!--#echo
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive <code>$ENV{'VAR'}</code>). Additionally you can dereference
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive it in a following RewriteCond pattern via
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive <code>%{ENV:VAR}</code>. Use this to strip but remember
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive information from URLs.</li>
6deb8bcfb8511ac38243a8274fc589842841b398ianh '<strong><code>cookie|CO=</code></strong><em>NAME</em>:<em>VAL</em>:<em>domain</em>[:<em>lifetime</em>[:<em>path</em>]]'
854cc4d3451547c2359c27870a3c354ad385a49bianh This sets a cookie on the client's browser. The cookie's name
854cc4d3451547c2359c27870a3c354ad385a49bianh <em>VAL</em>. The <em>domain</em> field is the domain of the
6deb8bcfb8511ac38243a8274fc589842841b398ianh cookie, such as '.apache.org',the optional <em>lifetime</em>
6deb8bcfb8511ac38243a8274fc589842841b398ianh is the lifetime of the cookie in minutes, and the optional
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive<note><title>Note</title> Never forget that <em>Pattern</em> is
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfsliveapplied to a complete URL in per-server configuration
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslivefiles. <strong>But in per-directory configuration files, the
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfsliveper-directory prefix (which always is the same for a specific
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslivedirectory!) is automatically <em>removed</em> for the pattern matching
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfsliveand automatically <em>added</em> after the substitution has been
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslivedone.</strong> This feature is essential for many sorts of rewriting,
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslivebecause without this prefix stripping you have to match the parent
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslivedirectory which is not always possible.
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive <p>There is one exception: If a substitution string
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive starts with ``<code>http://</code>'' then the directory
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive external redirect or proxy throughput (if flag
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive To enable the rewriting engine
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive for per-directory configuration files you need to set
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive FollowSymLinks</code>'' must be enabled. If your
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive administrator has disabled override of
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive <code>FollowSymLinks</code> for a user's directory, then
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive you cannot use the rewriting engine. This restriction is
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive needed for security reasons.
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive <p>Here are all possible substitution combinations and their
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive meanings:</p>
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive for request ``<code>GET
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive<strong>Given Rule</strong> <strong>Resulting Substitution</strong>
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive---------------------------------------------- ----------------------------------
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive^/somepath(.*) otherpath$1 not supported, because invalid!
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive^/somepath(.*) otherpath$1 [R] not supported, because invalid!
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive^/somepath(.*) otherpath$1 [P] not supported, because invalid!
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive---------------------------------------------- ----------------------------------
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive^/somepath(.*) /otherpath$1 [R] http://thishost/otherpath/pathinfo
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive via external redirection
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive^/somepath(.*) /otherpath$1 [P] not supported, because silly!
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive---------------------------------------------- ----------------------------------
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive^/somepath(.*) http://thishost/otherpath$1 /otherpath/pathinfo
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive^/somepath(.*) http://thishost/otherpath$1 [R] http://thishost/otherpath/pathinfo
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive via external redirection
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive^/somepath(.*) http://thishost/otherpath$1 [P] not supported, because silly!
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive---------------------------------------------- ----------------------------------
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive^/somepath(.*) http://otherhost/otherpath$1 http://otherhost/otherpath/pathinfo
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive via external redirection
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive^/somepath(.*) http://otherhost/otherpath$1 [R] http://otherhost/otherpath/pathinfo
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive via external redirection
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive (the [R] flag is redundant)
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive^/somepath(.*) http://otherhost/otherpath$1 [P] http://otherhost/otherpath/pathinfo
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive via internal proxy
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive for request ``<code>GET
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive<strong>Given Rule</strong> <strong>Resulting Substitution</strong>
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive---------------------------------------------- ----------------------------------
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive^localpath(.*) otherpath$1 /somepath/otherpath/pathinfo
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive^localpath(.*) otherpath$1 [R] http://thishost/somepath/otherpath/pathinfo
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive via external redirection
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive^localpath(.*) otherpath$1 [P] not supported, because silly!
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive---------------------------------------------- ----------------------------------
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive^localpath(.*) /otherpath$1 [R] http://thishost/otherpath/pathinfo
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive via external redirection
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive^localpath(.*) /otherpath$1 [P] not supported, because silly!
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive---------------------------------------------- ----------------------------------
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive^localpath(.*) http://thishost/otherpath$1 /otherpath/pathinfo
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive^localpath(.*) http://thishost/otherpath$1 [R] http://thishost/otherpath/pathinfo
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive via external redirection
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive^localpath(.*) http://thishost/otherpath$1 [P] not supported, because silly!
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive---------------------------------------------- ----------------------------------
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive^localpath(.*) http://otherhost/otherpath$1 http://otherhost/otherpath/pathinfo
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive via external redirection
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive^localpath(.*) http://otherhost/otherpath$1 [R] http://otherhost/otherpath/pathinfo
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive via external redirection
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive (the [R] flag is redundant)
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive^localpath(.*) http://otherhost/otherpath$1 [P] http://otherhost/otherpath/pathinfo
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive via internal proxy
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive <p>We take the rewrite mapfile from above and save it under
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive <code>/path/to/file/map.txt</code>. Then we only have to
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive add the following lines to the Apache server configuration
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfsliveRewriteRule ^/([^/]+)/~([^/]+)/(.*)$ /u/${real-to-user:$2|nobody}/$3.$1
013e1ddd21f2142a369c9a9a0eeb6c6a0bc3fcf3patrikj </directivesynopsis>
1c47b0c72c991a6f0ad172c74df0936fe13d6fbfslive</modulesynopsis>