CGIInfo - A Irie Pascal sample CGI program

This simple CGI program displays the contents of the standard CGI environment variables.

Program Listing

	(********************************************************************************************
	** PROGRAM     : cgiinfo
	** VERSION     : 1.0.1
	** DESCRIPTION : Displays commonly used CGI environment variables.
	** AUTHOR      : Stuart King
	** COPYRIGHT   : Copyright (c) Irie Tools, 2002-2010. All Rights Reserved.
	** NOTES       :
	**    This sample program is distributed with Irie Pascal, and is an example of how to
	** write CGI programs using Irie Pascal. To make best use of this sample you should have
	** a basic understanding of Pascal as well as a basic understanding of the
	** Common Gateway Interface (CGI).
	**********************************************************************************************)
	program info(output);

	procedure WriteResponseHeader;
	begin (* WriteResponseHeader *)
	writeln('content-type: text/html');
	writeln
	end; (* WriteResponseHeader *)

	procedure WriteHTMLHeader;
	begin (* WriteHTMLHeader *)
	writeln('<head>');
	writeln('<title>Irie Pascal sample CGI application</title>');
	writeln('</head>')
	end; (* WriteHTMLHeader *)

	procedure WriteHTMLBody;

	procedure DisplayEnvVar(name : string);
	var
	value : string;
	begin (* DisplayEnvVar *)
	value := getenv(name);
	writeln(name, ' = ', value, '<br>')
	end; (* DisplayEnvVar *)

	begin (* WriteHTMLBody *)
	writeln('<body>');

	writeln('<h1>This program displays the contents of the CGI environment variables.</h1>');

	DisplayEnvVar('HTTP_ACCEPT');
	DisplayEnvVar('HTTP_ACCEPT_ENCODING');
	DisplayEnvVar('HTTP_ACCEPT_LANGUAGE');
	DisplayEnvVar('HTTP_AUTHORIZATION');
	DisplayEnvVar('HTTP_CHARGE_TO');
	DisplayEnvVar('HTTP_FROM');
	DisplayEnvVar('HTTP_IF_MODIFIED_SINCE');
	DisplayEnvVar('HTTP_PRAGMA');
	DisplayEnvVar('HTTP_REFERER');
	DisplayEnvVar('HTTP_USER_AGENT');

	writeln('<hr>');

	DisplayEnvVar('AUTH_TYPE');
	DisplayEnvVar('CONTENT_LENGTH');
	DisplayEnvVar('CONTENT_TYPE');
	DisplayEnvVar('GATEWAY_INTERFACE');
	DisplayEnvVar('PATH_INFO');
	DisplayEnvVar('PATH_TRANSLATED');
	DisplayEnvVar('QUERY_STRING');
	DisplayEnvVar('REMOTE_ADDR');
	DisplayEnvVar('REMOTE_HOST');
	DisplayEnvVar('REMOTE_IDENT');
	DisplayEnvVar('REMOTE_USER');
	DisplayEnvVar('REQUEST_METHOD');
	DisplayEnvVar('SCRIPT_NAME');
	DisplayEnvVar('SERVER_NAME');
	DisplayEnvVar('SERVER_PORT');
	DisplayEnvVar('SERVER_PROTOCOL');
	(* Don't show this one for security purposes
	DisplayEnvVar('SERVER_SOFTWARE');
	*)

	writeln('</body>')
	end; (* WriteHTMLBody *)

	procedure WriteHTMLFooter;
	begin (* WriteHTMLFooter *)
	end; (* WriteHTMLFooter *)

	begin
	WriteResponseHeader;
	writeln('<html>');
	WriteHTMLHeader;
	WriteHTMLBody;
	writeln('</html>')
	end.

This program is included with Irie Pascal (in the samples directory).

Program Description

The program works as follows:

  1. WriteResponseHeader

    WriteResponseHeader writes the HTTP response header:

    	content-type: text/html

    which tells the client (usually a web browser) that the content of the response is a html text file.

    Notice that the built-in procedure writeln is used to write the response header to the standard output stream, and on to the waiting web server.

    Notice also the second writeln, which is used to write a blank line after the response header. The blank line tells the web server that the response header is finished, and that what follows is the response file.

  2. writeln('<html>');

    writeln('<html>'); writes the open html tag (marking the beginning of the html response file).

  3. WriteHTMLHeader

    WriteHTMLHeader writes a html header (containing just a title).

  4. WriteBody

    WriteBody writes the open body tag

    	<body>

    to indicate the start of the body of the html file.

    WriteBody then makes repeated calls to WriteEnvVar, to display the contents of the standard environment variables.

  5. writeln('</html>');

    writeln('</html>'); writes the close html tag (marking the end of the html response file).

  6. End of program

    When the program ends, the web server sends all of output to the client

Run the program

CGIInfo has been compiled and installed on this server. Click info.cgi.

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