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+<?xml version="1.0" encoding="ISO-8859-1"?>
+<!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><!--
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+<title>Custom Error Responses - Apache HTTP Server</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 href="./images/favicon.ico" rel="shortcut icon" /></head>
+<body id="manual-page"><div id="page-header">
+<p class="menu"><a href="./mod/">Modules</a> | <a href="./mod/directives.html">Directives</a> | <a href="./faq/">FAQ</a> | <a href="./glossary.html">Glossary</a> | <a href="./sitemap.html">Sitemap</a></p>
+<p class="apache">Apache HTTP Server Version 2.0</p>
+<img alt="" src="./images/feather.gif" /></div>
+<div class="up"><a href="./"><img title="<-" alt="<-" src="./images/left.gif" /></a></div>
+<div id="path">
+<a href="http://www.apache.org/">Apache</a> > <a href="http://httpd.apache.org/">HTTP Server</a> > <a href="http://httpd.apache.org/docs/">Documentation</a> > <a href="./">Version 2.0</a></div><div id="page-content"><div id="preamble"><h1>Custom Error Responses</h1>
+<div class="toplang">
+<p><span>Available Languages: </span><a href="./en/custom-error.html" title="English"> en </a> |
+<a href="./es/custom-error.html" hreflang="es" rel="alternate" title="Español"> es </a> |
+<a href="./fr/custom-error.html" hreflang="fr" rel="alternate" title="Français"> fr </a> |
+<a href="./ja/custom-error.html" hreflang="ja" rel="alternate" title="Japanese"> ja </a> |
+<a href="./ko/custom-error.html" hreflang="ko" rel="alternate" title="Korean"> ko </a> |
+<a href="./tr/custom-error.html" hreflang="tr" rel="alternate" title="Türkçe"> tr </a></p>
+</div>
+
+ <p>Additional functionality allows webmasters to configure the response
+ of Apache to some error or problem.</p>
+
+ <p>Customizable responses can be defined to be activated in the event of
+ a server detected error or problem.</p>
+
+ <p>If a script crashes and produces a "500 Server Error" response,
+ then this response can be replaced with either some friendlier text or by
+ a redirection to another URL (local or external).</p>
+ </div>
+<div id="quickview"><ul id="toc"><li><img alt="" src="./images/down.gif" /> <a href="#behavior">Behavior</a></li>
+<li><img alt="" src="./images/down.gif" /> <a href="#configuration">Configuration</a></li>
+<li><img alt="" src="./images/down.gif" /> <a href="#custom">Custom Error Responses and Redirects</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="behavior" id="behavior">Behavior</a></h2>
+
+
+ <h3>Old Behavior</h3>
+
+
+ <p>NCSA httpd 1.3 would return some boring old error/problem message
+ which would often be meaningless to the user, and would provide no
+ means of logging the symptoms which caused it.</p>
+
+
+ <h3>New Behavior</h3>
+
+
+ <p>The server can be asked to:</p>
+
+ <ol>
+ <li>Display some other text, instead of the NCSA hard coded
+ messages, or</li>
+
+ <li>redirect to a local URL, or</li>
+
+ <li>redirect to an external URL.</li>
+ </ol>
+
+ <p>Redirecting to another URL can be useful, but only if some
+ information can be passed which can then be used to explain and/or log
+ the error/problem more clearly.</p>
+
+ <p>To achieve this, Apache will define new CGI-like environment
+ variables:</p>
+
+ <div class="example"><p><code>
+ REDIRECT_HTTP_ACCEPT=*/*, image/gif, image/x-xbitmap,
+ image/jpeg<br />
+ REDIRECT_HTTP_USER_AGENT=Mozilla/1.1b2 (X11; I; HP-UX A.09.05
+ 9000/712)<br />
+ REDIRECT_PATH=.:/bin:/usr/local/bin:/etc<br />
+ REDIRECT_QUERY_STRING=<br />
+ REDIRECT_REMOTE_ADDR=121.345.78.123<br />
+ REDIRECT_REMOTE_HOST=ooh.ahhh.com<br />
+ REDIRECT_SERVER_NAME=crash.bang.edu<br />
+ REDIRECT_SERVER_PORT=80<br />
+ REDIRECT_SERVER_SOFTWARE=Apache/0.8.15<br />
+ REDIRECT_URL=/cgi-bin/buggy.pl
+ </code></p></div>
+
+ <p>Note the <code>REDIRECT_</code> prefix.</p>
+
+ <p>At least <code>REDIRECT_URL</code> and
+ <code>REDIRECT_QUERY_STRING</code> will be passed to the
+ new URL (assuming it's a cgi-script or a cgi-include). The
+ other variables will exist only if they existed prior to
+ the error/problem. <strong>None</strong> of these will be
+ set if your <code class="directive"><a href="./mod/core.html#errordocument">ErrorDocument</a></code> is an
+ <em>external</em> redirect (anything starting with a
+ scheme name like <code>http:</code>, even if it refers to the same host
+ as the server).</p>
+
+ </div><div class="top"><a href="#page-header"><img alt="top" src="./images/up.gif" /></a></div>
+<div class="section">
+<h2><a name="configuration" id="configuration">Configuration</a></h2>
+
+
+ <p>Use of <code class="directive"><a href="./mod/core.html#errordocument">ErrorDocument</a></code> is enabled
+ for .htaccess files when the
+ <code class="directive"><a href="./mod/core.html#allowoverride">AllowOverride</a></code> is set accordingly.</p>
+
+ <p>Here are some examples...</p>
+
+ <div class="example"><p><code>
+ ErrorDocument 500 /cgi-bin/crash-recover <br />
+ ErrorDocument 500 "Sorry, our script crashed. Oh dear" <br />
+ ErrorDocument 500 http://xxx/ <br />
+ ErrorDocument 404 /Lame_excuses/not_found.html <br />
+ ErrorDocument 401 /Subscription/how_to_subscribe.html
+ </code></p></div>
+
+ <p>The syntax is,</p>
+
+ <div class="example"><p><code>
+ ErrorDocument <3-digit-code> <action>
+ </code></p></div>
+
+ <p>where the action can be,</p>
+
+ <ol>
+ <li>Text to be displayed. Prefix the text with a quote
+ ("). Whatever follows the quote is displayed. <em>Note:
+ the (") prefix isn't displayed.</em></li>
+
+ <li>An external URL to redirect to.</li>
+
+ <li>A local URL to redirect to.</li>
+ </ol>
+ </div><div class="top"><a href="#page-header"><img alt="top" src="./images/up.gif" /></a></div>
+<div class="section">
+<h2><a name="custom" id="custom">Custom Error Responses and Redirects</a></h2>
+
+
+ <p>Apache's behavior to redirected URLs has been modified so
+ that additional environment variables are available to a
+ script/server-include.</p>
+
+ <h3>Old behavior</h3>
+
+
+ <p>Standard CGI vars were made available to a script which
+ has been redirected to. No indication of where the
+ redirection came from was provided.</p>
+
+
+ <h3>New behavior</h3>
+
+
+ <p>A new batch of environment variables will be initialized
+ for use by a script which has been redirected to. Each new
+ variable will have the prefix <code>REDIRECT_</code>.
+ <code>REDIRECT_</code> environment variables are created from
+ the CGI environment variables which existed prior to the
+ redirect, they are renamed with a <code>REDIRECT_</code>
+ prefix, <em>i.e.</em>, <code>HTTP_USER_AGENT</code> becomes
+ <code>REDIRECT_HTTP_USER_AGENT</code>. In addition to these
+ new variables, Apache will define <code>REDIRECT_URL</code>
+ and <code>REDIRECT_STATUS</code> to help the script trace its
+ origin. Both the original URL and the URL being redirected to
+ can be logged in the access log.</p>
+
+ <p>If the ErrorDocument specifies a local redirect to a CGI
+ script, the script should include a "<code>Status:</code>"
+ header field in its output in order to ensure the propagation
+ all the way back to the client of the error condition that
+ caused it to be invoked. For instance, a Perl ErrorDocument
+ script might include the following:</p>
+
+ <div class="example"><p><code>
+ ... <br />
+ print "Content-type: text/html\n"; <br />
+ printf "Status: %s Condition Intercepted\n", $ENV{"REDIRECT_STATUS"}; <br />
+ ...
+ </code></p></div>
+
+ <p>If the script is dedicated to handling a particular error
+ condition, such as <code>404 Not Found</code>, it can
+ use the specific code and error text instead.</p>
+
+ <p>Note that the script <em>must</em> emit an appropriate
+ <code>Status:</code> header (such as <code>302 Found</code>), if the
+ response contains a <code>Location:</code> header (in order to issue a
+ client side redirect). Otherwise the <code>Location:</code> header may
+ have no effect.</p>
+
+ </div></div>
+<div class="bottomlang">
+<p><span>Available Languages: </span><a href="./en/custom-error.html" title="English"> en </a> |
+<a href="./es/custom-error.html" hreflang="es" rel="alternate" title="Español"> es </a> |
+<a href="./fr/custom-error.html" hreflang="fr" rel="alternate" title="Français"> fr </a> |
+<a href="./ja/custom-error.html" hreflang="ja" rel="alternate" title="Japanese"> ja </a> |
+<a href="./ko/custom-error.html" hreflang="ko" rel="alternate" title="Korean"> ko </a> |
+<a href="./tr/custom-error.html" hreflang="tr" rel="alternate" title="Türkçe"> tr </a></p>
+</div><div id="footer">
+<p class="apache">Copyright 2009 The Apache Software Foundation.<br />Licensed under the <a href="http://www.apache.org/licenses/LICENSE-2.0">Apache License, Version 2.0</a>.</p>
+<p class="menu"><a href="./mod/">Modules</a> | <a href="./mod/directives.html">Directives</a> | <a href="./faq/">FAQ</a> | <a href="./glossary.html">Glossary</a> | <a href="./sitemap.html">Sitemap</a></p></div>
+</body></html>
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