HELP! * GREY=local LOCAL HTML version of Foils prepared 18 March 97

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

From Introduction to CGI Programming CPS616 Spring 97 -- Spring Semester 97. by Nancy J. McCracken * Critical Information in IMAGE

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 Apr 29 1997