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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><!-- XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX This file is generated from xml source: DO NOT EDIT XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX --><title>Apache Tutorial: Dynamic Content with CGI - 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> > <a href="./">How-To / Tutorials</a></div><div id="page-content"><div id="preamble"><h1>Apache Tutorial: Dynamic Content with CGI</h1><div class="toplang"><p><span>Available Languages: </span><a href="../en/howto/cgi.html" title="English"> en </a> |<a href="../ja/howto/cgi.html" hreflang="ja" rel="alternate" title="Japanese"> ja </a> |<a href="../ko/howto/cgi.html" hreflang="ko" rel="alternate" title="Korean"> ko </a></p></div></div><div id="quickview"><ul id="toc"><li><img alt="" src="../images/down.gif" /> <a href="#intro">Introduction</a></li><li><img alt="" src="../images/down.gif" /> <a href="#configuring">Configuring Apache to permit CGI</a></li><li><img alt="" src="../images/down.gif" /> <a href="#writing">Writing a CGI program</a></li><li><img alt="" src="../images/down.gif" /> <a href="#troubleshoot">But it's still not working!</a></li><li><img alt="" src="../images/down.gif" /> <a href="#behindscenes">What's going on behind the scenes?</a></li><li><img alt="" src="../images/down.gif" /> <a href="#libraries">CGI modules/libraries</a></li><li><img alt="" src="../images/down.gif" /> <a href="#moreinfo">For more information</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="intro" id="intro">Introduction</a></h2> <table class="related"><tr><th>Related Modules</th><th>Related Directives</th></tr><tr><td><ul><li><code class="module"><a href="../mod/mod_alias.html">mod_alias</a></code></li><li><code class="module"><a href="../mod/mod_cgi.html">mod_cgi</a></code></li></ul></td><td><ul><li><code class="directive"><a href="../mod/mod_mime.html#addhandler">AddHandler</a></code></li><li><code class="directive"><a href="../mod/core.html#options">Options</a></code></li><li><code class="directive"><a href="../mod/mod_alias.html#scriptalias">ScriptAlias</a></code></li></ul></td></tr></table> <p>The CGI (Common Gateway Interface) defines a way for a web server to interact with external content-generating programs, which are often referred to as CGI programs or CGI scripts. It is the simplest, and most common, way to put dynamic content on your web site. This document will be an introduction to setting up CGI on your Apache web server, and getting started writing CGI programs.</p> </div><div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div><div class="section"><h2><a name="configuring" id="configuring">Configuring Apache to permit CGI</a></h2> <p>In order to get your CGI programs to work properly, you'll need to have Apache configured to permit CGI execution. There are several ways to do this.</p> <h3><a name="scriptalias" id="scriptalias">ScriptAlias</a></h3> <p>The <code class="directive"><a href="../mod/mod_alias.html#scriptalias">ScriptAlias</a></code> directive tells Apache that a particular directory is set aside for CGI programs. Apache will assume that every file in this directory is a CGI program, and will attempt to execute it, when that particular resource is requested by a client.</p> <p>The <code class="directive"><a href="../mod/mod_alias.html#scriptalias">ScriptAlias</a></code> directive looks like:</p> <div class="example"><p><code> ScriptAlias /cgi-bin/ /usr/local/apache2/cgi-bin/ </code></p></div> <p>The example shown is from your default <code>httpd.conf</code> configuration file, if you installed Apache in the default location. The <code class="directive"><a href="../mod/mod_alias.html#scriptalias">ScriptAlias</a></code> directive is much like the <code class="directive"><a href="../mod/mod_alias.html#alias">Alias</a></code> directive, which defines a URL prefix that is to mapped to a particular directory. <code class="directive">Alias</code> and <code class="directive">ScriptAlias</code> are usually used for directories that are outside of the <code class="directive"><a href="../mod/core.html#documentroot">DocumentRoot</a></code> directory. The difference between <code class="directive">Alias</code> and <code class="directive">ScriptAlias</code> is that <code class="directive">ScriptAlias</code> has the added meaning that everything under that URL prefix will be considered a CGI program. So, the example above tells Apache that any request for a resource beginning with <code>/cgi-bin/</code> should be served from the directory <code>/usr/local/apache2/cgi-bin/</code>, and should be treated as a CGI program.</p> <p>For example, if the URL <code>http://www.example.com/cgi-bin/test.pl</code> is requested, Apache will attempt to execute the file <code>/usr/local/apache2/cgi-bin/test.pl</code> and return the output. Of course, the file will have to exist, and be executable, and return output in a particular way, or Apache will return an error message.</p> <h3><a name="nonscriptalias" id="nonscriptalias">CGI outside of ScriptAlias directories</a></h3> <p>CGI programs are often restricted to <code class="directive"><a href="../mod/mod_alias.html#scriptalias">ScriptAlias</a></code>'ed directories for security reasons. In this way, administrators can tightly control who is allowed to use CGI programs. However, if the proper security precautions are taken, there is no reason why CGI programs cannot be run from arbitrary directories. For example, you may wish to let users have web content in their home directories with the <code class="directive"><a href="../mod/mod_userdir.html#userdir">UserDir</a></code> directive. If they want to have their own CGI programs, but don't have access to the main <code>cgi-bin</code> directory, they will need to be able to run CGI programs elsewhere.</p> <p>There are two steps to allowing CGI execution in an arbitrary directory. First, the <code>cgi-script</code> handler must be activated using the <code class="directive"><a href="../mod/mod_mime.html#addhandler">AddHandler</a></code> or <code class="directive"><a href="../mod/core.html#sethandler">SetHandler</a></code> directive. Second, <code>ExecCGI</code> must be specified in the <code class="directive"><a href="../mod/core.html#options">Options</a></code> directive.</p> <h3><a name="options" id="options">Explicitly using Options to permit CGI execution</a></h3> <p>You could explicitly use the <code class="directive"><a href="../mod/core.html#options">Options</a></code> directive, inside your main server configuration file, to specify that CGI execution was permitted in a particular directory:</p> <div class="example"><p><code> <Directory /usr/local/apache2/htdocs/somedir><br /> <span class="indent"> Options +ExecCGI<br /> </span> </Directory> </code></p></div> <p>The above directive tells Apache to permit the execution of CGI files. You will also need to tell the server what files are CGI files. The following <code class="directive"><a href="../mod/mod_mime.html#addhandler">AddHandler</a></code> directive tells the server to treat all files with the <code>cgi</code> or <code>pl</code> extension as CGI programs:</p> <div class="example"><p><code> AddHandler cgi-script .cgi .pl </code></p></div> <h3><a name="htaccess" id="htaccess">.htaccess files</a></h3> <p>The <a href="htaccess.html"><code>.htaccess</code> tutorial</a> shows how to activate CGI programs if you do not have access to <code>httpd.conf</code>.</p> <h3><a name="userdir" id="userdir">User Directories</a></h3> <p>To allow CGI program execution for any file ending in <code>.cgi</code> in users' directories, you can use the following configuration.</p> <div class="example"><p><code> <Directory /home/*/public_html><br /> <span class="indent"> Options +ExecCGI<br /> AddHandler cgi-script .cgi<br /> </span> </Directory> </code></p></div> <p>If you wish designate a <code>cgi-bin</code> subdirectory of a user's directory where everything will be treated as a CGI program, you can use the following.</p> <div class="example"><p><code> <Directory /home/*/public_html/cgi-bin><br /> <span class="indent"> Options ExecCGI<br /> SetHandler cgi-script<br /> </span> </Directory> </code></p></div> </div><div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div><div class="section"><h2><a name="writing" id="writing">Writing a CGI program</a></h2> <p>There are two main differences between ``regular'' programming, and CGI programming.</p> <p>First, all output from your CGI program must be preceded by a MIME-type header. This is HTTP header that tells the client what sort of content it is receiving. Most of the time, this will look like:</p> <div class="example"><p><code> Content-type: text/html </code></p></div> <p>Secondly, your output needs to be in HTML, or some other format that a browser will be able to display. Most of the time, this will be HTML, but occasionally you might write a CGI program that outputs a gif image, or other non-HTML content.</p> <p>Apart from those two things, writing a CGI program will look a lot like any other program that you might write.</p> <h3><a name="firstcgi" id="firstcgi">Your first CGI program</a></h3> <p>The following is an example CGI program that prints one line to your browser. Type in the following, save it to a file called <code>first.pl</code>, and put it in your <code>cgi-bin</code> directory.</p> <div class="example"><p><code> #!/usr/bin/perl<br /> print "Content-type: text/html\n\n";<br /> print "Hello, World."; </code></p></div> <p>Even if you are not familiar with Perl, you should be able to see what is happening here. The first line tells Apache (or whatever shell you happen to be running under) that this program can be executed by feeding the file to the interpreter found at the location <code>/usr/bin/perl</code>. The second line prints the content-type declaration we talked about, followed by two carriage-return newline pairs. This puts a blank line after the header, to indicate the end of the HTTP headers, and the beginning of the body. The third line prints the string "Hello, World.". And that's the end of it.</p> <p>If you open your favorite browser and tell it to get the address</p> <div class="example"><p><code> http://www.example.com/cgi-bin/first.pl </code></p></div> <p>or wherever you put your file, you will see the one line <code>Hello, World.</code> appear in your browser window. It's not very exciting, but once you get that working, you'll have a good chance of getting just about anything working.</p> </div><div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div><div class="section"><h2><a name="troubleshoot" id="troubleshoot">But it's still not working!</a></h2> <p>There are four basic things that you may see in your browser when you try to access your CGI program from the web:</p> <dl> <dt>The output of your CGI program</dt> <dd>Great! That means everything worked fine. If the output is correct, but the browser is not processing it correctly, make sure you have the correct <code>Content-Type</code> set in your CGI program.</dd> <dt>The source code of your CGI program or a "POST Method Not Allowed" message</dt> <dd>That means that you have not properly configured Apache to process your CGI program. Reread the section on <a href="#configuring">configuring Apache</a> and try to find what you missed.</dd> <dt>A message starting with "Forbidden"</dt> <dd>That means that there is a permissions problem. Check the <a href="#errorlogs">Apache error log</a> and the section below on <a href="#permissions">file permissions</a>.</dd> <dt>A message saying "Internal Server Error"</dt> <dd>If you check the <a href="#errorlogs">Apache error log</a>, you will probably find that it says "Premature end of⌨️ 快捷键说明
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