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diff --git a/rubbos/app/apache2/manual/howto/cgi.html.en b/rubbos/app/apache2/manual/howto/cgi.html.en new file mode 100644 index 00000000..c3299f6c --- /dev/null +++ b/rubbos/app/apache2/manual/howto/cgi.html.en @@ -0,0 +1,555 @@ +<?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 + script headers", possibly along with an error message + generated by your CGI program. In this case, you will want to + check each of the below sections to see what might be + preventing your CGI program from emitting the proper HTTP + headers.</dd> + </dl> + + <h3><a name="permissions" id="permissions">File permissions</a></h3> + + + <p>Remember that the server does not run as you. That is, + when the server starts up, it is running with the permissions + of an unprivileged user - usually <code>nobody</code>, or + <code>www</code> - and so it will need extra permissions to + execute files that are owned by you. Usually, the way to give + a file sufficient permissions to be executed by <code>nobody</code> + is to give everyone execute permission on the file:</p> + + <div class="example"><p><code> + chmod a+x first.pl + </code></p></div> + + <p>Also, if your program reads from, or writes to, any other + files, those files will need to have the correct permissions + to permit this.</p> + + + + <h3><a name="pathinformation" id="pathinformation">Path information and environment</a></h3> + + + <p>When you run a program from your command line, you have + certain information that is passed to the shell without you + thinking about it. For example, you have a <code>PATH</code>, + which tells the shell where it can look for files that you + reference.</p> + + <p>When a program runs through the web server as a CGI program, + it may not have the same <code>PATH</code>. Any programs that you + invoke in your CGI program (like <code>sendmail</code>, for + example) will need to be specified by a full path, so that the + shell can find them when it attempts to execute your CGI + program.</p> + + <p>A common manifestation of this is the path to the script + interpreter (often <code>perl</code>) indicated in the first + line of your CGI program, which will look something like:</p> + + <div class="example"><p><code> + #!/usr/bin/perl + </code></p></div> + + <p>Make sure that this is in fact the path to the + interpreter.</p> + + <p>In addition, if your CGI program depends on other <a href="#env">environment variables</a>, you will need to + assure that those variables are passed by Apache.</p> + + + + <h3><a name="syntaxerrors" id="syntaxerrors">Program errors</a></h3> + + + <p>Most of the time when a CGI program fails, it's because of + a problem with the program itself. This is particularly true + once you get the hang of this CGI stuff, and no longer make + the above two mistakes. The first thing to do is to make + sure that your program runs from the command line before + testing it via the web server. For example, try:</p> + + <div class="example"><p><code> + cd /usr/local/apache2/cgi-bin<br /> + ./first.pl + </code></p></div> + + <p>(Do not call the <code>perl</code> interpreter. The shell + and Apache should find the interpreter using the <a href="#pathinformation">path information</a> on the first line of + the script.)</p> + + <p>The first thing you see written by your program should be + a set of HTTP headers, including the <code>Content-Type</code>, + followed by a blank line. If you see anything else, Apache will + return the <code>Premature end of script headers</code> error if + you try to run it through the server. See <a href="#writing">Writing a CGI program</a> above for more + details.</p> + + + <h3><a name="errorlogs" id="errorlogs">Error logs</a></h3> + + + <p>The error logs are your friend. Anything that goes wrong + generates message in the error log. You should always look + there first. If the place where you are hosting your web site + does not permit you access to the error log, you should + probably host your site somewhere else. Learn to read the + error logs, and you'll find that almost all of your problems + are quickly identified, and quickly solved.</p> + + + <h3><a name="suexec" id="suexec">Suexec</a></h3> + + + <p>The <a href="../suexec.html">suexec</a> support program + allows CGI programs to be run under different user permissions, + depending on which virtual host or user home directory they are + located in. Suexec has very strict permission checking, and any + failure in that checking will result in your CGI programs + failing with <code>Premature end of script headers</code>.</p> + + <p>To check if you are using suexec, run <code>apachectl + -V</code> and check for the location of <code>SUEXEC_BIN</code>. + If Apache finds an <code class="program"><a href="../programs/suexec.html">suexec</a></code> binary there on startup, + suexec will be activated.</p> + + <p>Unless you fully understand suexec, you should not be using it. + To disable suexec, simply remove (or rename) the <code class="program"><a href="../programs/suexec.html">suexec</a></code> + binary pointed to by <code>SUEXEC_BIN</code> and then restart the + server. If, after reading about <a href="../suexec.html">suexec</a>, + you still wish to use it, then run <code>suexec -V</code> to find + the location of the suexec log file, and use that log file to + find what policy you are violating.</p> + + </div><div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div> +<div class="section"> +<h2><a name="behindscenes" id="behindscenes">What's going on behind the scenes?</a></h2> + + + <p>As you become more advanced in CGI programming, it will + become useful to understand more about what's happening behind + the scenes. Specifically, how the browser and server + communicate with one another. Because although it's all very + well to write a program that prints "Hello, World.", it's not + particularly useful.</p> + + <h3><a name="env" id="env">Environment variables</a></h3> + + + <p>Environment variables are values that float around you as + you use your computer. They are useful things like your path + (where the computer searches for the actual file + implementing a command when you type it), your username, your + terminal type, and so on. For a full list of your normal, + every day environment variables, type + <code>env</code> at a command prompt.</p> + + <p>During the CGI transaction, the server and the browser + also set environment variables, so that they can communicate + with one another. These are things like the browser type + (Netscape, IE, Lynx), the server type (Apache, IIS, WebSite), + the name of the CGI program that is being run, and so on.</p> + + <p>These variables are available to the CGI programmer, and + are half of the story of the client-server communication. The + complete list of required variables is at + <a href="http://hoohoo.ncsa.uiuc.edu/cgi/env.html">http://hoohoo.ncsa.uiuc.edu/cgi/env.html</a>.</p> + + <p>This simple Perl CGI program will display all of the + environment variables that are being passed around. Two + similar programs are included in the + <code>cgi-bin</code> + + directory of the Apache distribution. Note that some + variables are required, while others are optional, so you may + see some variables listed that were not in the official list. + In addition, Apache provides many different ways for you to + <a href="../env.html">add your own environment variables</a> + to the basic ones provided by default.</p> + + <div class="example"><p><code> + #!/usr/bin/perl<br /> + print "Content-type: text/html\n\n";<br /> + foreach $key (keys %ENV) {<br /> + <span class="indent"> + print "$key --> $ENV{$key}<br>";<br /> + </span> + } + </code></p></div> + + + <h3><a name="stdin" id="stdin">STDIN and STDOUT</a></h3> + + + <p>Other communication between the server and the client + happens over standard input (<code>STDIN</code>) and standard + output (<code>STDOUT</code>). In normal everyday context, + <code>STDIN</code> means the keyboard, or a file that a + program is given to act on, and <code>STDOUT</code> + usually means the console or screen.</p> + + <p>When you <code>POST</code> a web form to a CGI program, + the data in that form is bundled up into a special format + and gets delivered to your CGI program over <code>STDIN</code>. + The program then can process that data as though it was + coming in from the keyboard, or from a file</p> + + <p>The "special format" is very simple. A field name and + its value are joined together with an equals (=) sign, and + pairs of values are joined together with an ampersand + (&). Inconvenient characters like spaces, ampersands, and + equals signs, are converted into their hex equivalent so that + they don't gum up the works. The whole data string might look + something like:</p> + + <div class="example"><p><code> + name=Rich%20Bowen&city=Lexington&state=KY&sidekick=Squirrel%20Monkey + </code></p></div> + + <p>You'll sometimes also see this type of string appended to + a URL. When that is done, the server puts that string + into the environment variable called + <code>QUERY_STRING</code>. That's called a <code>GET</code> + request. Your HTML form specifies whether a <code>GET</code> + or a <code>POST</code> is used to deliver the data, by setting the + <code>METHOD</code> attribute in the <code>FORM</code> tag.</p> + + <p>Your program is then responsible for splitting that string + up into useful information. Fortunately, there are libraries + and modules available to help you process this data, as well + as handle other of the aspects of your CGI program.</p> + + </div><div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div> +<div class="section"> +<h2><a name="libraries" id="libraries">CGI modules/libraries</a></h2> + + + <p>When you write CGI programs, you should consider using a + code library, or module, to do most of the grunt work for you. + This leads to fewer errors, and faster development.</p> + + <p>If you're writing CGI programs in Perl, modules are + available on <a href="http://www.cpan.org/">CPAN</a>. The most + popular module for this purpose is <code>CGI.pm</code>. You might + also consider <code>CGI::Lite</code>, which implements a minimal + set of functionality, which is all you need in most programs.</p> + + <p>If you're writing CGI programs in C, there are a variety of + options. One of these is the <code>CGIC</code> library, from + <a href="http://www.boutell.com/cgic/">http://www.boutell.com/cgic/</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="moreinfo" id="moreinfo">For more information</a></h2> + + + <p>There are a large number of CGI resources on the web. You + can discuss CGI problems with other users on the Usenet group + <a href="news:comp.infosystems.www.authoring.cgi">comp.infosystems.www.authoring.cgi</a>. And the -servers mailing + list from the HTML Writers Guild is a great source of answers + to your questions. You can find out more at + <a href="http://www.hwg.org/lists/hwg-servers/">http://www.hwg.org/lists/hwg-servers/</a>.</p> + + <p>And, of course, you should probably read the CGI + specification, which has all the details on the operation of + CGI programs. You can find the original version at the + <a href="http://hoohoo.ncsa.uiuc.edu/cgi/interface.html">NCSA</a> and there is an updated draft at the + <a href="http://web.golux.com/coar/cgi/">Common Gateway + Interface RFC project</a>.</p> + + <p>When you post a question about a CGI problem that you're + having, whether to a mailing list, or to a newsgroup, make sure + you provide enough information about what happened, what you + expected to happen, and how what actually happened was + different, what server you're running, what language your CGI + program was in, and, if possible, the offending code. This will + make finding your problem much simpler.</p> + + <p>Note that questions about CGI problems should <strong>never</strong> + be posted to the Apache bug database unless you are sure you + have found a problem in the Apache source code.</p> + </div></div> +<div class="bottomlang"> +<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 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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