webapps/docs/cgi-howto.xml - tomcat80 - Git at Google

 <?xml version="1.0" encoding="UTF-8"?>
 <!--
   Licensed to the Apache Software Foundation (ASF) under one or more
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   The ASF licenses this file to You under the Apache License, Version 2.0
   (the "License"); you may not use this file except in compliance with
   the License.  You may obtain a copy of the License at

       http://www.apache.org/licenses/LICENSE-2.0

   Unless required by applicable law or agreed to in writing, software
   distributed under the License is distributed on an "AS IS" BASIS,
   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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   limitations under the License.
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 <!DOCTYPE document [
   <!ENTITY project SYSTEM "project.xml">
 ]>
 <document url="cgi-howto.html">

     &project;

     <properties>
         <title>CGI How To</title>
     </properties>

 <body>

 <section name="Table of Contents">
 <toc/>
 </section>

 <section name="Introduction">

 <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.
 </p>

 <p>Within Tomcat, CGI support can be added when you are using Tomcat as your
 HTTP server and require CGI support.  Typically this is done
 during development when you don't want to run a web server like
 Apache httpd.
 Tomcat's CGI support is largely compatible with Apache httpd's,
 but there are some limitations (e.g., only one cgi-bin directory).
 </p>

 <p>CGI support is implemented using the servlet class
 <code>org.apache.catalina.servlets.CGIServlet</code>.  Traditionally,
 this servlet is mapped to the URL pattern "/cgi-bin/*".</p>

 <p>By default CGI support is disabled in Tomcat.</p>
 </section>

 <section name="Installation">

 <p><strong>CAUTION</strong> - CGI scripts are used to execute programs
 external to the Tomcat JVM. If you are using the Java SecurityManager this
 will bypass your security policy configuration in <code>catalina.policy.</code></p>

 <p>To enable CGI support:</p>

 <ol>
 <li><p>There are commented-out sample servlet and servlet-mapping elements for
 CGI servlet in the default <code>$CATALINA_BASE/conf/web.xml</code> file.
 To enable CGI support in your web application, copy that servlet and
 servlet-mapping declarations into <code>WEB-INF/web.xml</code> file of your
 web application.</p>

 <p>Uncommenting the servlet and servlet-mapping in
 <code>$CATALINA_BASE/conf/web.xml</code> file enables CGI for all installed
 web applications at once.</p>
 </li>

 <li><p>Set <code>privileged="true"</code> on the Context element for your
 web application.</p>

 <p>Only Contexts which are marked as privileged are allowed to use the
 CGI servlet. Note that modifying the global <code>$CATALINA_BASE/conf/context.xml</code>
 file affects all web applications. See
 <a href="config/context.html">Context documentation</a> for details.</p>
 </li>
 </ol>

 </section>

 <section name="Configuration">

 <p>There are several servlet init parameters which can be used to
 configure the behaviour of the CGI servlet.</p>
 <ul>
 <li><strong>cgiPathPrefix</strong> - The CGI search path will start at
 the web application root directory + File.separator + this prefix.
 By default there is no value, which results in the web application root
 directory being used as the search path. The recommended value is
 <code>WEB-INF/cgi</code></li>
 <li><strong>executable</strong> - The name of the executable to be used to
 run the script. You may explicitly set this parameter to be an empty string
 if your script is itself executable (e.g. an exe file). Default is
 <code>perl</code>.</li>
 <li><strong>executable-arg-1</strong>, <strong>executable-arg-2</strong>,
 and so on - additional arguments for the executable. These precede the
 CGI script name. By default there are no additional arguments.</li>
 <li><strong>envHttpHeaders</strong> - A regular expression used to select the
 HTTP headers passed to the CGI process as environment variables. Note that
 headers are converted to upper case before matching and that the entire header
 name must match the pattern. Default is
 <code>ACCEPT[-0-9A-Z]*|CACHE-CONTROL|COOKIE|HOST|IF-[-0-9A-Z]*|REFERER|USER-AGENT</code>
 </li>
 <li><strong>parameterEncoding</strong> - Name of the parameter encoding
 to be used with the CGI servlet. Default is
 <code>System.getProperty("file.encoding","UTF-8")</code>. That is the system
 default encoding, or UTF-8 if that system property is not available.</li>
 <li><strong>passShellEnvironment</strong> - Should the shell environment
 variables from Tomcat process (if any) be passed to the CGI script? Default is
 <code>false</code>.</li>
 <li><strong>stderrTimeout</strong> - The time (in milliseconds) to wait for
 the reading of stderr to complete before terminating the CGI process. Default
 is <code>2000</code>.</li>
 </ul>

 <p>The name and path of the CGI script to search for in the CGI search path
 depends on how the Servlet has been mapped. If the <strong>pathInfo</strong> is
 <code>null</code>, the <strong>servletPath</strong> will be used. If the
 <strong>pathInfo</strong> is not <code>null</code> then the
 <strong>servletPath</strong> is appended to the CGI search path and the
 <strong>pathInfo</strong> is used.</p>

 <p>The search will start with the first path segment and expand one path segment
 at a time until no path segments are left (resulting in a 404) or a matching
 script is found in the CGI search path. Any remaining path segments will be
 passed to the CGI executable in the <strong>PATH_INFO</strong> environment
 variable.</p>

 </section>

 </body>

 </document>
	<?xml version="1.0" encoding="UTF-8"?>
	<!--
	Licensed to the Apache Software Foundation (ASF) under one or more
	contributor license agreements. See the NOTICE file distributed with
	this work for additional information regarding copyright ownership.
	The ASF licenses this file to You under the Apache License, Version 2.0
	(the "License"); you may not use this file except in compliance with
	the License. You may obtain a copy of the License at

	http://www.apache.org/licenses/LICENSE-2.0

	Unless required by applicable law or agreed to in writing, software
	distributed under the License is distributed on an "AS IS" BASIS,
	WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
	See the License for the specific language governing permissions and
	limitations under the License.
	-->
	<!DOCTYPE document [
	<!ENTITY project SYSTEM "project.xml">
	]>
	<document url="cgi-howto.html">

	&project;

	<properties>
	<title>CGI How To</title>
	</properties>

	<body>

	<section name="Table of Contents">
	<toc/>
	</section>

	<section name="Introduction">

	<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.
	</p>

	<p>Within Tomcat, CGI support can be added when you are using Tomcat as your
	HTTP server and require CGI support. Typically this is done
	during development when you don't want to run a web server like
	Apache httpd.
	Tomcat's CGI support is largely compatible with Apache httpd's,
	but there are some limitations (e.g., only one cgi-bin directory).
	</p>

	<p>CGI support is implemented using the servlet class
	<code>org.apache.catalina.servlets.CGIServlet</code>. Traditionally,
	this servlet is mapped to the URL pattern "/cgi-bin/*".</p>

	<p>By default CGI support is disabled in Tomcat.</p>
	</section>

	<section name="Installation">

	<p><strong>CAUTION</strong> - CGI scripts are used to execute programs
	external to the Tomcat JVM. If you are using the Java SecurityManager this
	will bypass your security policy configuration in <code>catalina.policy.</code></p>

	<p>To enable CGI support:</p>

	<ol>
	<li><p>There are commented-out sample servlet and servlet-mapping elements for
	CGI servlet in the default <code>$CATALINA_BASE/conf/web.xml</code> file.
	To enable CGI support in your web application, copy that servlet and
	servlet-mapping declarations into <code>WEB-INF/web.xml</code> file of your
	web application.</p>

	<p>Uncommenting the servlet and servlet-mapping in
	<code>$CATALINA_BASE/conf/web.xml</code> file enables CGI for all installed
	web applications at once.</p>
	</li>

	<li><p>Set <code>privileged="true"</code> on the Context element for your
	web application.</p>

	<p>Only Contexts which are marked as privileged are allowed to use the
	CGI servlet. Note that modifying the global <code>$CATALINA_BASE/conf/context.xml</code>
	file affects all web applications. See
	<a href="config/context.html">Context documentation</a> for details.</p>
	</li>
	</ol>

	</section>

	<section name="Configuration">

	<p>There are several servlet init parameters which can be used to
	configure the behaviour of the CGI servlet.</p>
	<ul>
	<li><strong>cgiPathPrefix</strong> - The CGI search path will start at
	the web application root directory + File.separator + this prefix.
	By default there is no value, which results in the web application root
	directory being used as the search path. The recommended value is
	<code>WEB-INF/cgi</code></li>
	<li><strong>executable</strong> - The name of the executable to be used to
	run the script. You may explicitly set this parameter to be an empty string
	if your script is itself executable (e.g. an exe file). Default is
	<code>perl</code>.</li>
	<li><strong>executable-arg-1</strong>, <strong>executable-arg-2</strong>,
	and so on - additional arguments for the executable. These precede the
	CGI script name. By default there are no additional arguments.</li>
	<li><strong>envHttpHeaders</strong> - A regular expression used to select the
	HTTP headers passed to the CGI process as environment variables. Note that
	headers are converted to upper case before matching and that the entire header
	name must match the pattern. Default is
	<code>ACCEPT[-0-9A-Z]\|CACHE-CONTROL\|COOKIE\|HOST\|IF-[-0-9A-Z]\|REFERER\|USER-AGENT</code>
	</li>
	<li><strong>parameterEncoding</strong> - Name of the parameter encoding
	to be used with the CGI servlet. Default is
	<code>System.getProperty("file.encoding","UTF-8")</code>. That is the system
	default encoding, or UTF-8 if that system property is not available.</li>
	<li><strong>passShellEnvironment</strong> - Should the shell environment
	variables from Tomcat process (if any) be passed to the CGI script? Default is
	<code>false</code>.</li>
	<li><strong>stderrTimeout</strong> - The time (in milliseconds) to wait for
	the reading of stderr to complete before terminating the CGI process. Default
	is <code>2000</code>.</li>
	</ul>

	<p>The name and path of the CGI script to search for in the CGI search path
	depends on how the Servlet has been mapped. If the <strong>pathInfo</strong> is
	<code>null</code>, the <strong>servletPath</strong> will be used. If the
	<strong>pathInfo</strong> is not <code>null</code> then the
	<strong>servletPath</strong> is appended to the CGI search path and the
	<strong>pathInfo</strong> is used.</p>

	<p>The search will start with the first path segment and expand one path segment
	at a time until no path segments are left (resulting in a 404) or a matching
	script is found in the CGI search path. Any remaining path segments will be
	passed to the CGI executable in the <strong>PATH_INFO</strong> environment
	variable.</p>

	</section>

	</body>

	</document>