lighttpd/doc/fastcgi-state.txt

=================
FastCGI Internals
=================

---------------
Module: fastcgi
---------------

:Author: Jan Kneschke
:Date: $Date: 2004/08/01 07:01:29 $
:Revision: $Revision: 1.1 $

:abstract:
  This is a short summary of the state-engine which is driving the FastCGI
  module. It describes the basic concepts and the way the different parts
  of the module are connected.

.. meta::
  :keywords: lighttpd, state-engine, fastcgi

.. contents:: Table of Contents

Description
===========

States
------

The state-engine is currently made of 6 states which are walk-through on
the way each connection.

:init:
  prepare fastcgi-connection
:connect:
  waiting for a connection
:prepwrite:
  build the fastcgi-request
:write:
  write the fastcgi-request to the network
:read:
  read fastcgi-response from network and push it to the write-queue
:close:
  terminate the connection

.. image:: fastcgi-state.png

Delays
------

connect, write and read may need to wait for an fdevent. That's the reason
for the loop in the state-diagram.