The FastCGI interface was created with speed in mind, while giving a programming environment almost equal to the CGI protocol. FastCGI distinguishes between Responders and Authenticators, both of which can get a request and issue a response. However, most FastCGI applications just use the Responder part of the protocol.

A FastCGI application runs in a while-loop, with the rest of the program being written in plain CGI style. As the program runs continuously, we can store data between requests; also the setup cost is removed for all requests but the first. A typical program would look like this (in most languages):

<startup>
while (FCGI_Accept())
<handle request>
<cleanup>

The FastCGI protocol comes with libraries for C, Perl and Java. In addition, there are FastCGI libraries in many programming languages. PHP even comes with an optional FastCGI-compatible interpreter. Visit http://www.fastcgi.org/ to find the library for your favorite language, or read Chapter 13...