Add CGI docs

author: Denis Vlasenko <vda.linux@googlemail.com> 2007-02-11 14:52:07 +0000
committer: Denis Vlasenko <vda.linux@googlemail.com> 2007-02-11 14:52:07 +0000
commit: 136f42f503cb3e9588e62332d043e92b7475ec4e (patch)
tree: 81c556d1a136112be07bbd2c19293e65fad03cdd /docs/cgi
parent: ad67a3925c78e7c9f8e61248f640c5cc7a5cf186 (diff)
download: busybox-136f42f503cb3e9588e62332d043e92b7475ec4e.tar.gz
5 files changed, 383 insertions, 0 deletions
diff --git a/docs/cgi/cl.html b/docs/cgi/cl.html
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+<html><head><title>CGI Command line options</title></head><body><h1><img alt="" src="cl_files/CGIlogo.gif"> CGI Command line options</h1>
+<hr> <p>
+
+</p><h2>Specification</h2>
+
+The command line is only used in the case of an ISINDEX query. It is
+not used in the case of an HTML form or any as yet undefined query
+type. The server should search the query information (the <code>QUERY_STRING</code> environment variable) for a non-encoded
+= character to determine if the command line is to be used, if it
+finds one, the command line is not to be used. This trusts the clients
+to encode the = sign in ISINDEX queries, a practice which was
+considered safe at the time of the design of this specification. <p>
+
+For example, use the <a href="http://hoohoo.ncsa.uiuc.edu/cgi-bin/finger">finger script</a> and the ISINDEX interface to look up "httpd".  You will see that the script will call itself with <code>/cgi-bin/finger?httpd</code> and will actually execute "finger httpd" on the command line and output the results to you.
+</p><p>
+If the server does find a "=" in the <code>QUERY_STRING</code>,
+then the command line will not be used, and no decoding will be
+performed. The query then remains intact for processing by an
+appropriate FORM submission decoder.
+Again, as an example, use <a href="http://hoohoo.ncsa.uiuc.edu/cgi-bin/finger?httpd=name">this hyperlink</a> to submit <code>"httpd=name"</code> to the finger script.  Since this <code>QUERY_STRING</code>
+contained an unencoded "=", nothing was decoded, the script didn't know
+it was being submitted a valid query, and just gave you the default
+finger form.
+</p><p>
+If the server finds that it cannot send the string due to internal
+limitations (such as exec() or /bin/sh command line restrictions) the
+server should include NO command line information and provide the
+non-decoded query information in the environment
+variable <a href="http://hoohoo.ncsa.uiuc.edu/cgi/env.html#query"><code>QUERY_STRING</code></a>. </p><p>
+</p><hr>
+<h2>Examples</h2>
+
+Examples of the command line usage are much better <a href="http://hoohoo.ncsa.uiuc.edu/cgi/examples.html">demonstrated</a> than explained. For these
+examples, pay close attention to the script output which says what
+argc and argv are. <p>
+
+</p><hr>
+
+<a href="http://hoohoo.ncsa.uiuc.edu/cgi/interface.html"><img alt="[Back]" src="cl_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
diff --git a/docs/cgi/env.html b/docs/cgi/env.html
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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
diff --git a/docs/cgi/in.html b/docs/cgi/in.html
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+<html><head><title>CGI Script input</title></head><body><h1><img alt="" src="in_files/CGIlogo.gif"> CGI Script Input</h1>
+<hr>
+
+<h2>Specification</h2>
+
+For requests which have information attached after the header, such as
+HTTP POST or PUT, the information will be sent to the script on stdin.
+<p>
+
+The server will send <a href="http://hoohoo.ncsa.uiuc.edu/cgi/env.html#cl">CONTENT_LENGTH</a> bytes on
+this file descriptor. Remember that it will give the <a href="http://hoohoo.ncsa.uiuc.edu/cgi/env.html#ct">CONTENT_TYPE</a> of the data as well. The server is
+in no way obligated to send end-of-file after the script reads
+<code>CONTENT_LENGTH</code> bytes. </p><p>
+</p><hr>
+<h2>Example</h2>
+
+Let's take a form with METHOD="POST" as an example. Let's say the form
+results are 7 bytes encoded, and look like <code>a=b&amp;b=c</code>.
+<p>
+
+In this case, the server will set CONTENT_LENGTH to 7 and CONTENT_TYPE
+to application/x-www-form-urlencoded. The first byte on the script's
+standard input will be "a", followed by the rest of the encoded string.</p><p>
+
+</p><hr>
+
+<a href="http://hoohoo.ncsa.uiuc.edu/cgi/interface.html"><img alt="[Back]" src="in_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
diff --git a/docs/cgi/interface.html b/docs/cgi/interface.html
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+<html><head><title>The Common Gateway Interface Specification
+[http://hoohoo.ncsa.uiuc.edu/cgi/interface.html]
+</title></head><body><h1><img alt="" src="interface_files/CGIlogo.gif"> The CGI Specification</h1>
+
+<hr>
+
+This is the specification for CGI version 1.1, or CGI/1.1. Further
+revisions of this protocol are guaranteed to be backward compatible.
+<p>
+
+The server and the CGI script communicate in four major ways. Each of
+the following is a hotlink to graphic detail.</p><p>
+
+</p><ul>
+<li> <a href="env.html">Environment variables</a> 
+</li><li> <a href="cl.html">The command line</a>
+</li><li> <a href="in.html">Standard input</a>
+</li><li> <a href="out.html">Standard output</a>
+</li></ul>
+<hr>
+
+
+<a href="http://hoohoo.ncsa.uiuc.edu/cgi/overview.html"><img alt="[Back]" src="interface_files/back.gif">Return to the overview</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
diff --git a/docs/cgi/out.html b/docs/cgi/out.html
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+<html><head><title>CGI Script output</title></head><body><h1><img alt="" src="out_files/CGIlogo.gif"> CGI Script Output</h1>
+<hr>
+
+<h2>Script output</h2>
+
+The script sends its output to stdout. This output can either be a
+document generated by the script, or instructions to the server for
+retrieving the desired output. <p>
+</p><hr>
+
+<h2>Script naming conventions</h2>
+
+Normally, scripts produce output which is interpreted and sent back to
+the client. An advantage of this is that the scripts do not need to
+send a full HTTP/1.0 header for every request.  <p>
+<a name="nph">
+Some scripts may want to avoid the extra overhead of the server
+parsing their output, and talk directly to the client. In order to
+distinguish these scripts from the other scripts, CGI requires that
+the script name begins with nph- if a script does not want the server
+to parse its header. In this case, it is the script's responsibility
+to return a valid HTTP/1.0 (or HTTP/0.9) response to the client.  </a></p><p>
+
+</p><hr>
+<h2><a name="nph">Parsed headers</a></h2>
+
+<a name="nph">The output of scripts begins with a small header. This header consists
+of text lines, in the same format as an </a><a href="http://www.w3.org/hypertext/WWW/Protocols/HTTP/Object_Headers.html">
+HTTP header</a>, terminated by a blank line (a line with only a
+linefeed or CR/LF). <p>
+
+Any headers which are not server directives are sent directly back to
+the client. Currently, this specification defines three server
+directives:</p><p>
+
+</p><ul>
+<li> <code>Content-type</code> <p>
+
+    This is the MIME type of the document you are returning.  </p><p>
+
+</p></li><li> <code>Location</code> <p>
+
+    This is used to specify to the server that you are returning a
+    reference to a document rather than an actual document. </p><p>
+
+    If the argument to this is a URL, the server will issue a redirect
+    to the client. </p><p>
+
+    If the argument to this is a virtual path, the server will
+    retrieve the document specified as if the client had requested
+    that document originally. ? directives will work in here, but #
+    directives must be redirected back to the client.</p><p>
+
+
+</p></li><li> <a name="status"><code>Status</code></a><p>
+
+    This is used to give the server an HTTP/1.0 <a href="http://www.w3.org/hypertext/WWW/Protocols/HTTP/HTRESP.html">status
+line</a> to send to the client. The format is <code>nnn xxxxx</code>,
+where <code>nnn</code> is the 3-digit status code, and
+<code>xxxxx</code> is the reason string, such as "Forbidden".</p><p>
+
+</p></li></ul>
+
+<hr>
+<h2>Examples</h2>
+
+Let's say I have a fromgratz to HTML converter. When my converter is
+finished with its work, it will output the following on stdout (note
+that the lines beginning and ending with --- are just for illustration
+and would not be output): <p>
+
+</p><pre>--- start of output ---
+Content-type: text/html
+
+--- end of output ---
+</pre>
+
+Note the blank line after Content-type. <p>
+
+Now, let's say I have a script which, in certain instances, wants to
+return the document <code>/path/doc.txt</code> from this server just
+as if the user had actually requested
+<code>http://server:port/path/doc.txt</code> to begin with. In this
+case, the script would output: </p><p>
+</p><pre>--- start of output ---
+Location: /path/doc.txt
+
+--- end of output ---
+</pre>
+
+The server would then perform the request and send it to the client.
+<p>
+
+Let's say that I have a script which wants to reference our gopher
+server. In this case, if the script wanted to refer the user to
+<code>gopher://gopher.ncsa.uiuc.edu/</code>, it would output: </p><p>
+
+</p><pre>--- start of output ---
+Location: gopher://gopher.ncsa.uiuc.edu/
+
+--- end of output ---
+</pre>
+
+Finally, I have a script which wants to talk to the client directly.
+In this case, if the script is referenced with <a href="http://hoohoo.ncsa.uiuc.edu/cgi/env.html#protocol"><code>SERVER_PROTOCOL</code></a> of HTTP/1.0,
+the script would output the following HTTP/1.0 response: <p>
+
+</p><pre>--- start of output ---
+HTTP/1.0 200 OK
+Server: NCSA/1.0a6
+Content-type: text/plain
+
+This is a plaintext document generated on the fly just for you.
+
+--- end of output ---
+</pre>
+
+
+<hr>
+
+<a href="http://hoohoo.ncsa.uiuc.edu/cgi/interface.html"><img alt="[Back]" src="out_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
author	Denis Vlasenko <vda.linux@googlemail.com>	2007-02-11 14:52:07 +0000
committer	Denis Vlasenko <vda.linux@googlemail.com>	2007-02-11 14:52:07 +0000
commit	136f42f503cb3e9588e62332d043e92b7475ec4e (patch)
tree	81c556d1a136112be07bbd2c19293e65fad03cdd /docs/cgi
parent	ad67a3925c78e7c9f8e61248f640c5cc7a5cf186 (diff)
download	busybox-136f42f503cb3e9588e62332d043e92b7475ec4e.tar.gz