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| author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-07 15:01:30 +0000 |
|---|---|---|
| committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-07 15:01:30 +0000 |
| commit | 6beeb1b708550be0d4a53b272283e17e5e35fe17 (patch) | |
| tree | 1ce8673d4aaa948e5554000101f46536a1e4cc29 /docs/manual/rewrite/flags.html.en | |
| parent | Initial commit. (diff) | |
| download | apache2-3d46059c28a1d66e6e1aeb209491f1324c913a25.tar.xz apache2-3d46059c28a1d66e6e1aeb209491f1324c913a25.zip | |
Adding upstream version 2.4.57.upstream/2.4.57
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'docs/manual/rewrite/flags.html.en')
| -rw-r--r-- | docs/manual/rewrite/flags.html.en | 842 |
1 files changed, 842 insertions, 0 deletions
diff --git a/docs/manual/rewrite/flags.html.en b/docs/manual/rewrite/flags.html.en new file mode 100644 index 0000000..5e175f1 --- /dev/null +++ b/docs/manual/rewrite/flags.html.en @@ -0,0 +1,842 @@ +<?xml version="1.0" encoding="UTF-8"?> +<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd"> +<html xmlns="http://www.w3.org/1999/xhtml" lang="en" xml:lang="en"><head> +<meta content="text/html; charset=UTF-8" http-equiv="Content-Type" /> +<!-- + XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX + This file is generated from xml source: DO NOT EDIT + XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX + --> +<title>RewriteRule Flags - Apache HTTP Server Version 2.4</title> +<link href="../style/css/manual.css" rel="stylesheet" media="all" type="text/css" title="Main stylesheet" /> +<link href="../style/css/manual-loose-100pc.css" rel="alternate stylesheet" media="all" type="text/css" title="No Sidebar - Default font size" /> +<link href="../style/css/manual-print.css" rel="stylesheet" media="print" type="text/css" /><link rel="stylesheet" type="text/css" href="../style/css/prettify.css" /> +<script src="../style/scripts/prettify.min.js" type="text/javascript"> +</script> + +<link href="../images/favicon.ico" rel="shortcut icon" /></head> +<body id="manual-page"><div id="page-header"> +<p class="menu"><a href="../mod/">Modules</a> | <a href="../mod/directives.html">Directives</a> | <a href="http://wiki.apache.org/httpd/FAQ">FAQ</a> | <a href="../glossary.html">Glossary</a> | <a href="../sitemap.html">Sitemap</a></p> +<p class="apache">Apache HTTP Server Version 2.4</p> +<img alt="" src="../images/feather.png" /></div> +<div class="up"><a href="./"><img title="<-" alt="<-" src="../images/left.gif" /></a></div> +<div id="path"> +<a href="http://www.apache.org/">Apache</a> > <a href="http://httpd.apache.org/">HTTP Server</a> > <a href="http://httpd.apache.org/docs/">Documentation</a> > <a href="../">Version 2.4</a> > <a href="./">Rewrite</a></div><div id="page-content"><div id="preamble"><h1>RewriteRule Flags</h1> +<div class="toplang"> +<p><span>Available Languages: </span><a href="../en/rewrite/flags.html" title="English"> en </a> | +<a href="../fr/rewrite/flags.html" hreflang="fr" rel="alternate" title="Français"> fr </a></p> +</div> + +<p>This document discusses the flags which are available to the +<code class="directive"><a href="../mod/mod_rewrite.html#rewriterule">RewriteRule</a></code> directive, +providing detailed explanations and examples.</p> +</div> +<div id="quickview"><a href="https://www.apache.org/foundation/contributing.html" class="badge"><img src="https://www.apache.org/images/SupportApache-small.png" alt="Support Apache!" /></a><ul id="toc"><li><img alt="" src="../images/down.gif" /> <a href="#introduction">Introduction</a></li> +<li><img alt="" src="../images/down.gif" /> <a href="#flag_b">B (escape backreferences)</a></li> +<li><img alt="" src="../images/down.gif" /> <a href="#flag_bnp">BNP|backrefnoplus (don't escape space to +)</a></li> +<li><img alt="" src="../images/down.gif" /> <a href="#flag_bctls">BCTLS</a></li> +<li><img alt="" src="../images/down.gif" /> <a href="#flag_bne">BNE</a></li> +<li><img alt="" src="../images/down.gif" /> <a href="#flag_c">C|chain</a></li> +<li><img alt="" src="../images/down.gif" /> <a href="#flag_co">CO|cookie</a></li> +<li><img alt="" src="../images/down.gif" /> <a href="#flag_dpi">DPI|discardpath</a></li> +<li><img alt="" src="../images/down.gif" /> <a href="#flag_e">E|env</a></li> +<li><img alt="" src="../images/down.gif" /> <a href="#flag_end">END</a></li> +<li><img alt="" src="../images/down.gif" /> <a href="#flag_f">F|forbidden</a></li> +<li><img alt="" src="../images/down.gif" /> <a href="#flag_g">G|gone</a></li> +<li><img alt="" src="../images/down.gif" /> <a href="#flag_h">H|handler</a></li> +<li><img alt="" src="../images/down.gif" /> <a href="#flag_l">L|last</a></li> +<li><img alt="" src="../images/down.gif" /> <a href="#flag_n">N|next</a></li> +<li><img alt="" src="../images/down.gif" /> <a href="#flag_nc">NC|nocase</a></li> +<li><img alt="" src="../images/down.gif" /> <a href="#flag_ne">NE|noescape</a></li> +<li><img alt="" src="../images/down.gif" /> <a href="#flag_ns">NS|nosubreq</a></li> +<li><img alt="" src="../images/down.gif" /> <a href="#flag_p">P|proxy</a></li> +<li><img alt="" src="../images/down.gif" /> <a href="#flag_pt">PT|passthrough</a></li> +<li><img alt="" src="../images/down.gif" /> <a href="#flag_qsa">QSA|qsappend</a></li> +<li><img alt="" src="../images/down.gif" /> <a href="#flag_qsd">QSD|qsdiscard</a></li> +<li><img alt="" src="../images/down.gif" /> <a href="#flag_qsl">QSL|qslast</a></li> +<li><img alt="" src="../images/down.gif" /> <a href="#flag_r">R|redirect</a></li> +<li><img alt="" src="../images/down.gif" /> <a href="#flag_s">S|skip</a></li> +<li><img alt="" src="../images/down.gif" /> <a href="#flag_t">T|type</a></li> +</ul><h3>See also</h3><ul class="seealso"><li><a href="../mod/mod_rewrite.html">Module documentation</a></li><li><a href="intro.html">mod_rewrite introduction</a></li><li><a href="remapping.html">Redirection and remapping</a></li><li><a href="access.html">Controlling access</a></li><li><a href="vhosts.html">Virtual hosts</a></li><li><a href="proxy.html">Proxying</a></li><li><a href="rewritemap.html">Using RewriteMap</a></li><li><a href="advanced.html">Advanced techniques</a></li><li><a href="avoid.html">When not to use mod_rewrite</a></li><li><a href="#comments_section">Comments</a></li></ul></div> +<div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div> +<div class="section"> +<h2><a name="introduction" id="introduction">Introduction</a></h2> +<p>A <code class="directive"><a href="../mod/mod_rewrite.html#rewriterule">RewriteRule</a></code> can have +its behavior modified by one or more flags. Flags are included in +square brackets at the end of the rule, and multiple flags are separated +by commas.</p> +<pre class="prettyprint lang-config">RewriteRule pattern target [Flag1,Flag2,Flag3]</pre> + + +<p>Each flag (with a few exceptions) has a short form, such as +<code>CO</code>, as well as a longer form, such as <code>cookie</code>. +While it is most common to use +the short form, it is recommended that you familiarize yourself with the +long form, so that you remember what each flag is supposed to do. +Some flags take one or more arguments. Flags are not case sensitive.</p> + +<p>Flags that alter metadata associated with the request (T=, H=, E=) +have no affect in per-directory and htaccess context, when a substitution +(other than '-') is performed during the same round of rewrite processing. +</p> + +<p>Presented here are each of the available flags, along with an example +of how you might use them.</p> +</div><div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div> +<div class="section"> +<h2><a name="flag_b" id="flag_b">B (escape backreferences)</a></h2> +<p>The [B] flag instructs <code class="directive"><a href="../mod/mod_rewrite.html#rewriterule">RewriteRule</a></code> to escape non-alphanumeric +characters before applying the transformation.</p> + +<p><code>mod_rewrite</code> has to unescape URLs before mapping them, +so backreferences are unescaped at the time they are applied. +Using the B flag, non-alphanumeric characters in backreferences +will be escaped. For example, consider the rule:</p> + +<pre class="prettyprint lang-config">RewriteRule "^search/(.*)$" "/search.php?term=$1"</pre> + + +<p>Given a search term of 'x & y/z', a browser will encode it as +'x%20%26%20y%2Fz', making the request 'search/x%20%26%20y%2Fz'. Without the B +flag, this rewrite rule will map to 'search.php?term=x & y/z', which +isn't a valid URL, and so would be encoded as +<code>search.php?term=x%20&y%2Fz=</code>, which is not what was intended.</p> + +<p>With the B flag set on this same rule, the parameters are re-encoded +before being passed on to the output URL, resulting in a correct mapping to +<code>/search.php?term=x%20%26%20y%2Fz</code>.</p> + +<pre class="prettyprint lang-config">RewriteRule "^search/(.*)$" "/search.php?term=$1" [B,PT]</pre> + + +<p>Note that you may also need to set <code class="directive"><a href="../mod/core.html#allowencodedslashes">AllowEncodedSlashes</a></code> to <code>On</code> to get this +particular example to work, as httpd does not allow encoded slashes in URLs, and +returns a 404 if it sees one.</p> + +<p>This escaping is particularly necessary in a proxy situation, +when the backend may break if presented with an unescaped URL.</p> + +<p>An alternative to this flag is using a <code class="directive"><a href="../mod/mod_rewrite.html#rewritecond">RewriteCond</a></code> to capture against %{THE_REQUEST} which will capture +strings in the encoded form.</p> + +<p>In 2.4.26 and later, you can limit the escaping to specific characters +in backreferences by listing them: <code>[B=#?;]</code>. Note: The space +character can be used in the list of characters to escape, but you must quote +the entire third argument of <code class="directive"><a href="../mod/mod_rewrite.html#rewriterule">RewriteRule</a></code> +and the space must not be the last character in the list.</p> + +<pre class="prettyprint lang-config"># Escape spaces and question marks. The quotes around the final argument +# are required when a space is included. +RewriteRule "^search/(.*)$" "/search.php?term=$1" "[B= ?]"</pre> + + +<p>To limit the characters escaped this way, see <a href="flag_bne">flag_bne</a> +and <a href="flag_bctls">flag_bctls</a></p> +</div><div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div> +<div class="section"> +<h2><a name="flag_bnp" id="flag_bnp">BNP|backrefnoplus (don't escape space to +)</a></h2> +<p>The [BNP] flag instructs <code class="directive"><a href="../mod/mod_rewrite.html#rewriterule">RewriteRule</a></code> to escape the space character +in a backreference to %20 rather than '+'. Useful when the backreference +will be used in the path component rather than the query string.</p> + +<pre class="prettyprint lang-config"># Escape spaces to %20 in the path instead of + as used in form submission via +# the query string +RewriteRule "^search/(.*)$" "/search.php/$1" "[B,BNP]"</pre> + + + +<p>This flag is available in version 2.4.26 and later.</p> +</div><div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div> +<div class="section"> +<h2><a name="flag_bctls" id="flag_bctls">BCTLS</a></h2> +<p>The [BCTLS] flag is similar to the [B] flag, but only escapes +control characters and the space character. This is the same set of +characters rejected when they are copied into the query string unencoded. +</p> + +<pre class="prettyprint lang-config"># Escape control characters and spaces +RewriteRule "^search/(.*)$" "/search.php/$1" "[BCTLS]"</pre> + + +<p>This flag is available in version 2.4.57 and later.</p> + +</div><div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div> +<div class="section"> +<h2><a name="flag_bne" id="flag_bne">BNE</a></h2> +<p>The list of characters in [BNE=...] are treated as exclusions to the +characters of the [B] or [BCTLS] flags. The listed characters will not be +escaped. +</p> + +<pre class="prettyprint lang-config"># Escape the default characters, but leave / +RewriteRule "^search/(.*)$" "/search.php?term=$1" "[B,BNE=/]"</pre> + + +<p>This flag is available in version 2.4.57 and later.</p> +</div><div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div> +<div class="section"> +<h2><a name="flag_c" id="flag_c">C|chain</a></h2> +<p>The [C] or [chain] flag indicates that the <code class="directive"><a href="../mod/mod_rewrite.html#rewriterule">RewriteRule</a></code> is chained to the next +rule. That is, if the rule matches, then it is processed as usual and +control moves on to the next rule. However, if it does not match, then +the next rule, and any other rules that are chained together, are +skipped.</p> + +</div><div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div> +<div class="section"> +<h2><a name="flag_co" id="flag_co">CO|cookie</a></h2> +<p>The [CO], or [cookie] flag, allows you to set a cookie when a +particular <code class="directive"><a href="../mod/mod_rewrite.html#rewriterule">RewriteRule</a></code> +matches. The argument consists of three required fields and five optional +fields.</p> + +<p>The full syntax for the flag, including all attributes, is as +follows:</p> + +<div class="example"><p><code> +[CO=NAME:VALUE:DOMAIN:lifetime:path:secure:httponly:samesite] +</code></p></div> + +<p>If a literal ':' character is needed in any of the cookie fields, an +alternate syntax is available. To opt-in to the alternate syntax, the cookie +"Name" should be preceded with a ';' character, and field separators should be +specified as ';'.</p> + +<div class="example"><p><code> +[CO=;NAME;VALUE:MOREVALUE;DOMAIN;lifetime;path;secure;httponly;samesite] +</code></p></div> + +<p>You must declare a name, a value, and a domain for the cookie to be set.</p> + +<dl> +<dt>Domain</dt> +<dd>The domain for which you want the cookie to be valid. This may be a +hostname, such as <code>www.example.com</code>, or it may be a domain, +such as <code>.example.com</code>. It must be at least two parts +separated by a dot. That is, it may not be merely <code>.com</code> or +<code>.net</code>. Cookies of that kind are forbidden by the cookie +security model.</dd> +</dl> + +<p>You may optionally also set the following values:</p> + +<dl> +<dt>Lifetime</dt> +<dd>The time for which the cookie will persist, in minutes.</dd> +<dd>A value of 0 indicates that the cookie will persist only for the +current browser session. This is the default value if none is +specified.</dd> + +<dt>Path</dt> +<dd>The path, on the current website, for which the cookie is valid, +such as <code>/customers/</code> or <code>/files/download/</code>.</dd> +<dd>By default, this is set to <code>/</code> - that is, the entire +website.</dd> + +<dt>Secure</dt> +<dd>If set to <code>secure</code>, <code>true</code>, or <code>1</code>, +the cookie will only be permitted to be translated via secure (https) +connections.</dd> + +<dt>httponly</dt> +<dd>If set to <code>HttpOnly</code>, <code>true</code>, or +<code>1</code>, the cookie will have the <code>HttpOnly</code> flag set, +which means that the cookie is inaccessible to JavaScript code on +browsers that support this feature.</dd> + +<dt>samesite</dt> +<dd>If set to anything other than <code>false</code> or <code>0</code>, the <code>SameSite</code> +attribute is set to the specified value. Typical values are <code>None</code>, +<code>Lax</code>, and <code>Strict</code>. Available in 2.4.47 and later.</dd> +</dl> + + +<p>Consider this example:</p> + +<pre class="prettyprint lang-config">RewriteEngine On +RewriteRule "^/index\.html" "-" [CO=frontdoor:yes:.example.com:1440:/]</pre> + + +<p>In the example give, the rule doesn't rewrite the request. +The "-" rewrite target tells mod_rewrite to pass the request +through unchanged. Instead, it sets a cookie +called 'frontdoor' to a value of 'yes'. The cookie is valid for any host +in the <code>.example.com</code> domain. It is set to expire in 1440 +minutes (24 hours) and is returned for all URIs.</p> + +</div><div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div> +<div class="section"> +<h2><a name="flag_dpi" id="flag_dpi">DPI|discardpath</a></h2> +<p>The DPI flag causes the PATH_INFO portion of the rewritten URI to be +discarded.</p> +<p>This flag is available in version 2.2.12 and later.</p> +<p>In per-directory context, the URI each <code class="directive">RewriteRule</code> +compares against is the concatenation of the current values of the URI +and PATH_INFO.</p> + +<p>The current URI can be the initial URI as requested by the client, the +result of a previous round of mod_rewrite processing, or the result of +a prior rule in the current round of mod_rewrite processing.</p> + +<p>In contrast, the PATH_INFO that is appended to the URI before each +rule reflects only the value of PATH_INFO before this round of +mod_rewrite processing. As a consequence, if large portions +of the URI are matched and copied into a substitution in multiple +<code class="directive">RewriteRule</code> directives, without regard for +which parts of the URI came from the current PATH_INFO, the final +URI may have multiple copies of PATH_INFO appended to it.</p> + +<p>Use this flag on any substitution where the PATH_INFO that resulted +from the previous mapping of this request to the filesystem is not of +interest. This flag permanently forgets the PATH_INFO established +before this round of mod_rewrite processing began. PATH_INFO will +not be recalculated until the current round of mod_rewrite processing +completes. Subsequent rules during this round of processing will see +only the direct result of substitutions, without any PATH_INFO +appended.</p> +</div><div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div> +<div class="section"> +<h2><a name="flag_e" id="flag_e">E|env</a></h2> +<p>With the [E], or [env] flag, you can set the value of an environment +variable. Note that some environment variables may be set after the rule +is run, thus unsetting what you have set. See <a href="../env.html">the +Environment Variables document</a> for more details on how Environment +variables work.</p> + +<p>The full syntax for this flag is:</p> + +<pre class="prettyprint lang-config">[E=VAR:VAL] +[E=!VAR]</pre> + + +<p><code>VAL</code> may contain backreferences (<code>$N</code> or +<code>%N</code>) which are expanded.</p> + +<p>Using the short form</p> + +<div class="example"><p><code> +[E=VAR] +</code></p></div> + +<p>you can set the environment variable named <code>VAR</code> to an +empty value.</p> + +<p>The form</p> + +<div class="example"><p><code> +[E=!VAR] +</code></p></div> + +<p>allows to unset a previously set environment variable named +<code>VAR</code>.</p> + +<p>Environment variables can then be used in a variety of +contexts, including CGI programs, other RewriteRule directives, or +CustomLog directives.</p> + +<p>The following example sets an environment variable called 'image' to a +value of '1' if the requested URI is an image file. Then, that +environment variable is used to exclude those requests from the access +log.</p> + +<pre class="prettyprint lang-config">RewriteRule "\.(png|gif|jpg)$" "-" [E=image:1] +CustomLog "logs/access_log" combined env=!image</pre> + + +<p>Note that this same effect can be obtained using <code class="directive"><a href="../mod/mod_setenvif.html#setenvif">SetEnvIf</a></code>. This technique is offered as +an example, not as a recommendation.</p> +</div><div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div> +<div class="section"> +<h2><a name="flag_end" id="flag_end">END</a></h2> +<p>Using the [END] flag terminates not only the current round of rewrite +processing (like [L]) but also prevents any subsequent rewrite +processing from occurring in per-directory (htaccess) context.</p> + +<p>This does not apply to new requests resulting from external +redirects.</p> +</div><div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div> +<div class="section"> +<h2><a name="flag_f" id="flag_f">F|forbidden</a></h2> +<p>Using the [F] flag causes the server to return a 403 Forbidden status +code to the client. While the same behavior can be accomplished using +the <code class="directive"><a href="../mod/mod_access_compat.html#deny">Deny</a></code> directive, this +allows more flexibility in assigning a Forbidden status.</p> + +<p>The following rule will forbid <code>.exe</code> files from being +downloaded from your server.</p> + +<pre class="prettyprint lang-config">RewriteRule "\.exe" "-" [F]</pre> + + +<p>This example uses the "-" syntax for the rewrite target, which means +that the requested URI is not modified. There's no reason to rewrite to +another URI, if you're going to forbid the request.</p> + +<p>When using [F], an [L] is implied - that is, the response is returned +immediately, and no further rules are evaluated.</p> + +</div><div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div> +<div class="section"> +<h2><a name="flag_g" id="flag_g">G|gone</a></h2> +<p>The [G] flag forces the server to return a 410 Gone status with the +response. This indicates that a resource used to be available, but is no +longer available.</p> + +<p>As with the [F] flag, you will typically use the "-" syntax for the +rewrite target when using the [G] flag:</p> + +<pre class="prettyprint lang-config">RewriteRule "oldproduct" "-" [G,NC]</pre> + + +<p>When using [G], an [L] is implied - that is, the response is returned +immediately, and no further rules are evaluated.</p> + +</div><div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div> +<div class="section"> +<h2><a name="flag_h" id="flag_h">H|handler</a></h2> +<p>Forces the resulting request to be handled with the specified +handler. For example, one might use this to force all files without a +file extension to be parsed by the php handler:</p> + +<pre class="prettyprint lang-config">RewriteRule "!\." "-" [H=application/x-httpd-php]</pre> + + +<p> +The regular expression above - <code>!\.</code> - will match any request +that does not contain the literal <code>.</code> character. +</p> + +<p>This can be also used to force the handler based on some conditions. +For example, the following snippet used in per-server context allows +<code>.php</code> files to be <em>displayed</em> by <code>mod_php</code> +if they are requested with the <code>.phps</code> extension:</p> + +<pre class="prettyprint lang-config">RewriteRule "^(/source/.+\.php)s$" "$1" [H=application/x-httpd-php-source]</pre> + + +<p>The regular expression above - <code>^(/source/.+\.php)s$</code> - will +match any request that starts with <code>/source/</code> followed by 1 or +n characters followed by <code>.phps</code> literally. The backreference +$1 referrers to the captured match within parenthesis of the regular +expression.</p> +</div><div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div> +<div class="section"> +<h2><a name="flag_l" id="flag_l">L|last</a></h2> +<p>The [L] flag causes <code class="module"><a href="../mod/mod_rewrite.html">mod_rewrite</a></code> to stop processing +the rule set. In most contexts, this means that if the rule matches, no +further rules will be processed. This corresponds to the +<code>last</code> command in Perl, or the <code>break</code> command in +C. Use this flag to indicate that the current rule should be applied +immediately without considering further rules.</p> + +<p>If you are using <code class="directive"><a href="../mod/mod_rewrite.html#rewriterule">RewriteRule</a></code> in either +<code>.htaccess</code> files or in +<code class="directive"><a href="../mod/core.html#directory"><Directory></a></code> sections, +it is important to have some understanding of how the rules are +processed. The simplified form of this is that once the rules have been +processed, the rewritten request is handed back to the URL parsing +engine to do what it may with it. It is possible that as the rewritten +request is handled, the <code>.htaccess</code> file or +<code class="directive"><a href="../mod/core.html#directory"><Directory></a></code> section +may be encountered again, and thus the ruleset may be run again from the +start. Most commonly this will happen if one of the rules causes a +redirect - either internal or external - causing the request process to +start over.</p> + +<p>It is therefore important, if you are using <code class="directive"><a href="../mod/mod_rewrite.html#rewriterule">RewriteRule</a></code> directives in one of these +contexts, that you take explicit steps to avoid rules looping, and not +count solely on the [L] flag to terminate execution of a series of +rules, as shown below.</p> + +<p> An alternative flag, [END], can be used to terminate not only the +current round of rewrite processing but prevent any subsequent +rewrite processing from occurring in per-directory (htaccess) +context. This does not apply to new requests resulting from external +redirects.</p> + +<p>The example given here will rewrite any request to +<code>index.php</code>, giving the original request as a query string +argument to <code>index.php</code>, however, the <code class="directive"><a href="../mod/mod_rewrite.html#rewritecond">RewriteCond</a></code> ensures that if the request +is already for <code>index.php</code>, the <code class="directive"><a href="../mod/mod_rewrite.html#rewriterule">RewriteRule</a></code> will be skipped.</p> + +<pre class="prettyprint lang-config">RewriteBase "/" +RewriteCond "%{REQUEST_URI}" !=/index.php +RewriteRule "^(.*)" "/index.php?req=$1" [L,PT]</pre> + +</div><div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div> +<div class="section"> +<h2><a name="flag_n" id="flag_n">N|next</a></h2> +<p> +The [N] flag causes the ruleset to start over again from the top, using +the result of the ruleset so far as a starting point. Use +with extreme caution, as it may result in loop. +</p> +<p> +The [Next] flag could be used, for example, if you wished to replace a +certain string or letter repeatedly in a request. The example shown here +will replace A with B everywhere in a request, and will continue doing +so until there are no more As to be replaced. +</p> +<pre class="prettyprint lang-config">RewriteRule "(.*)A(.*)" "$1B$2" [N]</pre> + +<p>You can think of this as a <code>while</code> loop: While this +pattern still matches (i.e., while the URI still contains an +<code>A</code>), perform this substitution (i.e., replace the +<code>A</code> with a <code>B</code>).</p> + +<p>In 2.4.8 and later, this module returns an error after 10,000 iterations to +protect against unintended looping. An alternative maximum number of +iterations can be specified by adding to the N flag. </p> +<pre class="prettyprint lang-config"># Be willing to replace 1 character in each pass of the loop +RewriteRule "(.+)[><;]$" "$1" [N=32000] +# ... or, give up if after 10 loops +RewriteRule "(.+)[><;]$" "$1" [N=10]</pre> + + +</div><div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div> +<div class="section"> +<h2><a name="flag_nc" id="flag_nc">NC|nocase</a></h2> +<p>Use of the [NC] flag causes the <code class="directive"><a href="../mod/mod_rewrite.html#rewriterule">RewriteRule</a></code> to be matched in a +case-insensitive manner. That is, it doesn't care whether letters appear +as upper-case or lower-case in the matched URI.</p> + +<p>In the example below, any request for an image file will be proxied +to your dedicated image server. The match is case-insensitive, so that +<code>.jpg</code> and <code>.JPG</code> files are both acceptable, for +example.</p> + +<pre class="prettyprint lang-config">RewriteRule "(.*\.(jpg|gif|png))$" "http://images.example.com$1" [P,NC]</pre> + +</div><div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div> +<div class="section"> +<h2><a name="flag_ne" id="flag_ne">NE|noescape</a></h2> +<p>By default, special characters, such as <code>&</code> and +<code>?</code>, for example, will be converted to their hexcode +equivalent for rules that result in external redirects. +Using the [NE] flag prevents that from happening. +</p> + +<pre class="prettyprint lang-config">RewriteRule "^/anchor/(.+)" "/bigpage.html#$1" [NE,R]</pre> + + +<p> +The above example will redirect <code>/anchor/xyz</code> to +<code>/bigpage.html#xyz</code>. Omitting the [NE] will result in the # +being converted to its hexcode equivalent, <code>%23</code>, which will +then result in a 404 Not Found error condition. +</p> + +</div><div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div> +<div class="section"> +<h2><a name="flag_ns" id="flag_ns">NS|nosubreq</a></h2> +<p>Use of the [NS] flag prevents the rule from being used on +subrequests. For example, a page which is included using an SSI (Server +Side Include) is a subrequest, and you may want to avoid rewrites +happening on those subrequests. Also, when <code class="module"><a href="../mod/mod_dir.html">mod_dir</a></code> +tries to find out information about possible directory default files +(such as <code>index.html</code> files), this is an internal +subrequest, and you often want to avoid rewrites on such subrequests. +On subrequests, it is not always useful, and can even cause errors, if +the complete set of rules are applied. Use this flag to exclude +problematic rules.</p> + +<p>To decide whether or not to use this rule: if you prefix URLs with +CGI-scripts, to force them to be processed by the CGI-script, it's +likely that you will run into problems (or significant overhead) +on sub-requests. In these cases, use this flag.</p> + +<p> +Images, javascript files, or css files, loaded as part of an HTML page, +are not subrequests - the browser requests them as separate HTTP +requests. +</p> +</div><div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div> +<div class="section"> +<h2><a name="flag_p" id="flag_p">P|proxy</a></h2> +<p>Use of the [P] flag causes the request to be handled by +<code class="module"><a href="../mod/mod_proxy.html">mod_proxy</a></code>, and handled via a proxy request. For +example, if you wanted all image requests to be handled by a back-end +image server, you might do something like the following:</p> + +<pre class="prettyprint lang-config">RewriteRule "/(.*)\.(jpg|gif|png)$" "http://images.example.com/$1.$2" [P]</pre> + + +<p>Use of the [P] flag implies [L] - that is, the request is immediately +pushed through the proxy, and any following rules will not be +considered.</p> + +<p> +You must make sure that the substitution string is a valid URI +(typically starting with <code>http://</code><em>hostname</em>) which can be +handled by the <code class="module"><a href="../mod/mod_proxy.html">mod_proxy</a></code>. If not, you will get an +error from the proxy module. Use this flag to achieve a +more powerful implementation of the <code class="directive"><a href="../mod/mod_proxy.html#proxypass">ProxyPass</a></code> directive, +to map remote content into the namespace of the local server.</p> + +<div class="warning"> +<h3>Security Warning</h3> +<p>Take care when constructing the target URL of the rule, considering +the security impact from allowing the client influence over the set of +URLs to which your server will act as a proxy. Ensure that the scheme +and hostname part of the URL is either fixed, or does not allow the +client undue influence.</p> +</div> + +<div class="warning"> +<h3>Performance warning</h3> +<p>Using this flag triggers the use of <code class="module"><a href="../mod/mod_proxy.html">mod_proxy</a></code>, without handling of persistent connections. This +means the performance of your proxy will be better if you set it up with <code class="directive"><a href="../mod/mod_proxy.html#proxypass">ProxyPass</a></code> or +<code class="directive"><a href="../mod/mod_proxy.html#proxypassmatch">ProxyPassMatch</a></code></p> +<p>This is because this flag triggers the use of the default worker, which does not handle connection pooling/reuse.</p> +<p>Avoid using this flag and prefer those directives, whenever you can.</p> +</div> + +<p>Note: <code class="module"><a href="../mod/mod_proxy.html">mod_proxy</a></code> must be enabled in order +to use this flag.</p> + +</div><div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div> +<div class="section"> +<h2><a name="flag_pt" id="flag_pt">PT|passthrough</a></h2> + +<p> +The target (or substitution string) in a RewriteRule is assumed to be a +file path, by default. The use of the [PT] flag causes it to be treated +as a URI instead. That is to say, the +use of the [PT] flag causes the result of the <code class="directive"><a href="../mod/mod_rewrite.html#rewriterule">RewriteRule</a></code> to be passed back through +URL mapping, so that location-based mappings, such as <code class="directive"><a href="../mod/mod_alias.html#alias">Alias</a></code>, <code class="directive"><a href="../mod/mod_alias.html#redirect">Redirect</a></code>, or <code class="directive"><a href="../mod/mod_alias.html#scriptalias">ScriptAlias</a></code>, for example, might have a +chance to take effect. +</p> + +<p> +If, for example, you have an +<code class="directive"><a href="../mod/mod_alias.html#alias">Alias</a></code> +for /icons, and have a <code class="directive"><a href="../mod/mod_rewrite.html#rewriterule">RewriteRule</a></code> pointing there, you should +use the [PT] flag to ensure that the +<code class="directive"><a href="../mod/mod_alias.html#alias">Alias</a></code> is evaluated. +</p> + +<pre class="prettyprint lang-config">Alias "/icons" "/usr/local/apache/icons" +RewriteRule "/pics/(.+)\.jpg$" "/icons/$1.gif" [PT]</pre> + + +<p> +Omission of the [PT] flag in this case will cause the Alias to be +ignored, resulting in a 'File not found' error being returned. +</p> + +<p>The <code>PT</code> flag implies the <code>L</code> flag: +rewriting will be stopped in order to pass the request to +the next phase of processing.</p> + +<p>Note that the <code>PT</code> flag is implied in per-directory +contexts such as +<code class="directive"><a href="../mod/core.html#directory"><Directory></a></code> sections +or in <code>.htaccess</code> files. The only way to circumvent that +is to rewrite to <code>-</code>.</p> + +</div><div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div> +<div class="section"> +<h2><a name="flag_qsa" id="flag_qsa">QSA|qsappend</a></h2> +<p> +When the replacement URI contains a query string, the default behavior +of <code class="directive"><a href="../mod/mod_rewrite.html#rewriterule">RewriteRule</a></code> is to discard +the existing query string, and replace it with the newly generated one. +Using the [QSA] flag causes the query strings to be combined. +</p> + +<p>Consider the following rule:</p> + +<pre class="prettyprint lang-config">RewriteRule "/pages/(.+)" "/page.php?page=$1" [QSA]</pre> + + +<p>With the [QSA] flag, a request for <code>/pages/123?one=two</code> will be +mapped to <code>/page.php?page=123&one=two</code>. Without the [QSA] +flag, that same request will be mapped to +<code>/page.php?page=123</code> - that is, the existing query string +will be discarded. +</p> +</div><div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div> +<div class="section"> +<h2><a name="flag_qsd" id="flag_qsd">QSD|qsdiscard</a></h2> +<p> +When the requested URI contains a query string, and the target URI does +not, the default behavior of <code class="directive"><a href="../mod/mod_rewrite.html#rewriterule">RewriteRule</a></code> is to copy that query +string to the target URI. Using the [QSD] flag causes the query string +to be discarded. +</p> + +<p>This flag is available in version 2.4.0 and later.</p> + +<p> +Using [QSD] and [QSA] together will result in [QSD] taking precedence. +</p> + +<p> +If the target URI has a query string, the default behavior will be +observed - that is, the original query string will be discarded and +replaced with the query string in the <code>RewriteRule</code> target +URI. +</p> + +</div><div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div> +<div class="section"> +<h2><a name="flag_qsl" id="flag_qsl">QSL|qslast</a></h2> +<p> +By default, the first (left-most) question mark in the substitution +delimits the path from the query string. Using the [QSL] flag instructs +<code class="directive"><a href="../mod/mod_rewrite.html#rewriterule">RewriteRule</a></code> to instead split +the two components using the last (right-most) question mark. </p> + +<p> +This is useful when mapping to files that have literal question marks in +their filename. If no query string is used in the substitution, +a question mark can be appended to it in combination with this flag. </p> + +<p> This flag is available in version 2.4.19 and later.</p> + +</div><div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div> +<div class="section"> +<h2><a name="flag_r" id="flag_r">R|redirect</a></h2> +<p> +Use of the [R] flag causes a HTTP redirect to be issued to the browser. +If a fully-qualified URL is specified (that is, including +<code>http://servername/</code>) then a redirect will be issued to that +location. Otherwise, the current protocol, servername, and port number +will be used to generate the URL sent with the redirect. +</p> + +<p> +<em>Any</em> valid HTTP response status code may be specified, +using the syntax [R=305], with a 302 status code being used by +default if none is specified. The status code specified need not +necessarily be a redirect (3xx) status code. However, +if a status code is outside the redirect range (300-399) then the +substitution string is dropped entirely, and rewriting is stopped as if +the <code>L</code> were used.</p> + +<p>In addition to response status codes, you may also specify redirect +status using their symbolic names: <code>temp</code> (default), +<code>permanent</code>, or <code>seeother</code>.</p> + +<p> +You will almost always want to use [R] in conjunction with [L] (that is, +use [R,L]) because on its own, the [R] flag prepends +<code>http://thishost[:thisport]</code> to the URI, but then passes this +on to the next rule in the ruleset, which can often result in 'Invalid +URI in request' warnings. +</p> + +</div><div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div> +<div class="section"> +<h2><a name="flag_s" id="flag_s">S|skip</a></h2> +<p>The [S] flag is used to skip rules that you don't want to run. The +syntax of the skip flag is [S=<em>N</em>], where <em>N</em> signifies +the number of rules to skip (provided the <code class="directive"><a href="../mod/mod_rewrite.html#rewriterule"> +RewriteRule</a></code> and any preceding <code class="directive"><a href="../mod/mod_rewrite.html#rewritecond"> +RewriteCond</a></code> directives match). This can be thought of as a +<code>goto</code> statement in your rewrite ruleset. In the following +example, we only want to run the <code class="directive"><a href="../mod/mod_rewrite.html#rewriterule"> +RewriteRule</a></code> if the requested URI doesn't correspond with an +actual file.</p> + +<pre class="prettyprint lang-config"># Is the request for a non-existent file? +RewriteCond "%{REQUEST_FILENAME}" !-f +RewriteCond "%{REQUEST_FILENAME}" !-d +# If so, skip these two RewriteRules +RewriteRule ".?" "-" [S=2] + +RewriteRule "(.*\.gif)" "images.php?$1" +RewriteRule "(.*\.html)" "docs.php?$1"</pre> + + +<p>This technique is useful because a <code class="directive"><a href="../mod/mod_rewrite.html#rewritecond">RewriteCond</a></code> only applies to the +<code class="directive"><a href="../mod/mod_rewrite.html#rewriterule">RewriteRule</a></code> immediately +following it. Thus, if you want to make a <code>RewriteCond</code> apply +to several <code>RewriteRule</code>s, one possible technique is to +negate those conditions and add a <code>RewriteRule</code> with a [Skip] flag. You can +use this to make pseudo if-then-else constructs: The last rule of +the then-clause becomes <code>skip=N</code>, where N is the +number of rules in the else-clause:</p> +<pre class="prettyprint lang-config"># Does the file exist? +RewriteCond "%{REQUEST_FILENAME}" !-f +RewriteCond "%{REQUEST_FILENAME}" !-d +# Create an if-then-else construct by skipping 3 lines if we meant to go to the "else" stanza. +RewriteRule ".?" "-" [S=3] + +# IF the file exists, then: + RewriteRule "(.*\.gif)" "images.php?$1" + RewriteRule "(.*\.html)" "docs.php?$1" + # Skip past the "else" stanza. + RewriteRule ".?" "-" [S=1] +# ELSE... + RewriteRule "(.*)" "404.php?file=$1" +# END</pre> + + +<p>It is probably easier to accomplish this kind of configuration using +the <code class="directive"><If></code>, <code class="directive"><ElseIf></code>, and <code class="directive"><Else></code> directives instead.</p> + +</div><div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div> +<div class="section"> +<h2><a name="flag_t" id="flag_t">T|type</a></h2> +<p>Sets the MIME type with which the resulting response will be +sent. This has the same effect as the <code class="directive"><a href="../mod/mod_mime.html#addtype">AddType</a></code> directive.</p> + +<p>For example, you might use the following technique to serve Perl +source code as plain text, if requested in a particular way:</p> + +<pre class="prettyprint lang-config"># Serve .pl files as plain text +RewriteRule "\.pl$" "-" [T=text/plain]</pre> + + +<p>Or, perhaps, if you have a camera that produces jpeg images without +file extensions, you could force those images to be served with the +correct MIME type by virtue of their file names:</p> + +<pre class="prettyprint lang-config"># Files with 'IMG' in the name are jpg images. +RewriteRule "IMG" "-" [T=image/jpg]</pre> + + +<p>Please note that this is a trivial example, and could be better done +using <code class="directive"><a href="../mod/core.html#filesmatch"><FilesMatch></a></code> +instead. Always consider the alternate +solutions to a problem before resorting to rewrite, which will +invariably be a less efficient solution than the alternatives.</p> + +<p> +If used in per-directory context, use only <code>-</code> (dash) +as the substitution <em>for the entire round of mod_rewrite processing</em>, +otherwise the MIME-type set with this flag is lost due to an internal +re-processing (including subsequent rounds of mod_rewrite processing). +The <code>L</code> flag can be useful in this context to end the +<em>current</em> round of mod_rewrite processing.</p> + +</div></div> +<div class="bottomlang"> +<p><span>Available Languages: </span><a href="../en/rewrite/flags.html" title="English"> en </a> | +<a href="../fr/rewrite/flags.html" hreflang="fr" rel="alternate" title="Français"> fr </a></p> +</div><div class="top"><a href="#page-header"><img src="../images/up.gif" alt="top" /></a></div><div class="section"><h2><a id="comments_section" name="comments_section">Comments</a></h2><div class="warning"><strong>Notice:</strong><br />This is not a Q&A section. 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