Basic HTML version of Foils prepared 2 Sept 1997

Foil 3 The Flow of Data amongst the Client, Server and CGI Script

From CGI Programming with Advanced Topics Jackson State University Mississippi -- Fall Semester 97. by Nancy McCracken *
The client sends a request, conforming to the URL standard and formatted with a MIME header, to the server.
The server parses the request and decides what to do:
  • for FTP and other services, the server makes an appropriate request of its operating system and responds.
  • for HTTP service, it retrieves the file named by the URL and decides what to do based on file type. An html, mpeg, au, or any other file with recognizable file extensions is returned directly to the client with no further processing (except in the case of Server Side Includes - SSI)
  • if the file is executable, the server executes it as a CGI program. The server processes the header to pass execution parameters as environment variables or as a STDIN stream to the CGI program.

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Page produced by wwwfoil on Tue Sep 2 1997