Re: Why FastCGI?

[Sam Hobbs <Sam@xxxxxxxxxxxxxxxxxx>]

See Common Gateway Interface - Wikipedia. It says:

The form's data is sent to the Web server within an HTTP request with a URL denoting a CGI script. The Web server then launches the CGI script in a new computer process, passing the form data to it. The output of the CGI script, usually in the form of HTML, is returned by the script to the Web server, and the server relays it back to the browser as its response to the browser's request.

For PHP, the CGI script (and the form) is the PHP file. The input is received using HTTP and the output of PHP is provided to the server and returned to the client using HTTP.

See RFC 3875 - The Common Gateway Interface (CGI) Version 1.1. It is the official definition CGI. Other protocols such as FastCGI perform the same function but are designed to be more efficient. The following are excerpts of the RFC.

Abstract

   The Common Gateway Interface (CGI) is a simple interface for running
   external programs, software or gateways under an information server
   in a platform-independent manner.  Currently, the supported
   information servers are HTTP servers.


1. Introduction
1.1. Purpose

{Two paragraphs omitted from here}

   The server is responsible for managing connection, data transfer,
   transport and network issues related to the client request, whereas
   the CGI script handles the application issues, such as data access
   and document processing.

Andrey Repin wrote on 3/25/2021 2:06 AM:

CGI is a protocol of exchanging information between client and server.