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authorDenis Vlasenko <vda.linux@googlemail.com>2007-02-11 14:52:07 +0000
committerDenis Vlasenko <vda.linux@googlemail.com>2007-02-11 14:52:07 +0000
commit136f42f503cb3e9588e62332d043e92b7475ec4e (patch)
tree81c556d1a136112be07bbd2c19293e65fad03cdd /docs/cgi/env.html
parentad67a3925c78e7c9f8e61248f640c5cc7a5cf186 (diff)
downloadbusybox-136f42f503cb3e9588e62332d043e92b7475ec4e.tar.gz
Add CGI docs
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+<html><head><title>CGI Environment Variables</title></head><body><h1><img alt="" src="env_files/CGIlogo.gif"> CGI Environment Variables</h1>
+<hr>
+
+<p>
+
+In order to pass data about the information request from the server to
+the script, the server uses command line arguments as well as
+environment variables. These environment variables are set when the
+server executes the gateway program. </p><p>
+
+</p><hr>
+<h2>Specification</h2>
+
+ <p>
+The following environment variables are not request-specific and are
+set for all requests: </p><p>
+
+</p><ul>
+<li> <code>SERVER_SOFTWARE</code> <p>
+
+ The name and version of the information server software answering
+ the request (and running the gateway). Format: name/version </p><p>
+
+</p></li><li> <code>SERVER_NAME</code> <p>
+ The server's hostname, DNS alias, or IP address as it would appear
+ in self-referencing URLs. </p><p>
+
+</p></li><li> <code>GATEWAY_INTERFACE</code> <p>
+ The revision of the CGI specification to which this server
+ complies. Format: CGI/revision</p><p>
+
+</p></li></ul>
+
+<hr>
+
+The following environment variables are specific to the request being
+fulfilled by the gateway program: <p>
+
+</p><ul>
+<li> <a name="protocol"><code>SERVER_PROTOCOL</code></a> <p>
+ The name and revision of the information protcol this request came
+ in with. Format: protocol/revision </p><p>
+
+</p></li><li> <code>SERVER_PORT</code> <p>
+ The port number to which the request was sent. </p><p>
+
+</p></li><li> <code>REQUEST_METHOD</code> <p>
+ The method with which the request was made. For HTTP, this is
+ "GET", "HEAD", "POST", etc. </p><p>
+
+</p></li><li> <code>PATH_INFO</code> <p>
+ The extra path information, as given by the client. In other
+ words, scripts can be accessed by their virtual pathname, followed
+ by extra information at the end of this path. The extra
+ information is sent as PATH_INFO. This information should be
+ decoded by the server if it comes from a URL before it is passed
+ to the CGI script.</p><p>
+
+</p></li><li> <code>PATH_TRANSLATED</code> <p>
+ The server provides a translated version of PATH_INFO, which takes
+ the path and does any virtual-to-physical mapping to it. </p><p>
+
+</p></li><li> <code>SCRIPT_NAME</code> <p>
+ A virtual path to the script being executed, used for
+ self-referencing URLs. </p><p>
+
+</p></li><li> <a name="query"><code>QUERY_STRING</code></a> <p>
+ The information which follows the ? in the <a href="http://www.ncsa.uiuc.edu/demoweb/url-primer.html">URL</a>
+ which referenced this script. This is the query information. It
+ should not be decoded in any fashion. This variable should always
+ be set when there is query information, regardless of <a href="http://hoohoo.ncsa.uiuc.edu/cgi/cl.html">command line decoding</a>. </p><p>
+
+</p></li><li> <code>REMOTE_HOST</code> <p>
+ The hostname making the request. If the server does not have this
+ information, it should set REMOTE_ADDR and leave this unset.</p><p>
+
+</p></li><li> <code>REMOTE_ADDR</code> <p>
+ The IP address of the remote host making the request. </p><p>
+
+</p></li><li> <code>AUTH_TYPE</code> <p>
+ If the server supports user authentication, and the script is
+ protects, this is the protocol-specific authentication method used
+ to validate the user. </p><p>
+
+</p></li><li> <code>REMOTE_USER</code> <p>
+ If the server supports user authentication, and the script is
+ protected, this is the username they have authenticated as. </p><p>
+</p></li><li> <code>REMOTE_IDENT</code> <p>
+ If the HTTP server supports RFC 931 identification, then this
+ variable will be set to the remote user name retrieved from the
+ server. Usage of this variable should be limited to logging only.
+ </p><p>
+
+</p></li><li> <a name="ct"><code>CONTENT_TYPE</code></a> <p>
+ For queries which have attached information, such as HTTP POST and
+ PUT, this is the content type of the data. </p><p>
+
+</p></li><li> <a name="cl"><code>CONTENT_LENGTH</code></a> <p>
+ The length of the said content as given by the client. </p><p>
+
+</p></li></ul>
+
+
+<a name="headers"><hr></a>
+
+In addition to these, the header lines received from the client, if
+any, are placed into the environment with the prefix HTTP_ followed by
+the header name. Any - characters in the header name are changed to _
+characters. The server may exclude any headers which it has already
+processed, such as Authorization, Content-type, and Content-length. If
+necessary, the server may choose to exclude any or all of these
+headers if including them would exceed any system environment
+limits. <p>
+
+An example of this is the HTTP_ACCEPT variable which was defined in
+CGI/1.0. Another example is the header User-Agent.</p><p>
+
+</p><ul>
+<li> <code>HTTP_ACCEPT</code> <p>
+ The MIME types which the client will accept, as given by HTTP
+ headers. Other protocols may need to get this information from
+ elsewhere. Each item in this list should be separated by commas as
+ per the HTTP spec. </p><p>
+
+ Format: type/subtype, type/subtype </p><p>
+
+
+</p></li><li> <code>HTTP_USER_AGENT</code><p>
+
+ The browser the client is using to send the request. General
+format: <code>software/version library/version</code>.</p><p>
+
+</p></li></ul>
+
+<hr>
+<h2>Examples</h2>
+
+Examples of the setting of environment variables are really much better
+<a href="http://hoohoo.ncsa.uiuc.edu/cgi/examples.html">demonstrated</a> than explained. <p>
+
+</p><hr>
+
+<a href="http://hoohoo.ncsa.uiuc.edu/cgi/interface.html"><img alt="[Back]" src="env_files/back.gif">Return to the
+interface specification</a> <p>
+
+CGI - Common Gateway Interface
+</p><address><a href="http://hoohoo.ncsa.uiuc.edu/cgi/mailtocgi.html">cgi@ncsa.uiuc.edu</a></address>
+
+</body></html> \ No newline at end of file