home *** CD-ROM | disk | FTP | other *** search
Wrap
<?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><!-- XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX This file is generated from xml source: DO NOT EDIT XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX --> <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 2.2</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 2.2</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="Espa±ol"> es </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></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="Espa±ol"> es </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></p> </div><div id="footer"> <p class="apache">Copyright 1995-2006 The Apache Software Foundation or its licensors, as applicable.<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>