Jifty::Manual::RequestHandling(3pm)			User Contributed Perl Documentation		       Jifty::Manual::RequestHandling(3pm)

NAME

       Jifty::Manual::RequestHandling - Jifty's request handling process

DESCRIPTION

       This document outlines some of Jifty's inside in order to help you to understand what happens during the request processing phase.

THE HANDLER

       As soon as a HTTP request (whatever the method might be, like GET, POST, PUT, ...) arrives at Jifty's border, the request is forwarded to a
       handler. By default, "Jifty->handler" points to a Jifty::Handler object that is responsible for handling an incoming request. The handler
       receives a CGI object on which it operates.

   The major steps in the request handling process are:
       refresh eventually modified modules in develop mode
	   This allows a perl developer to change perl modules being used in a Jifty application without the need to restart the server which
	   would otherwise become necessary. This is never done on a live environment.

       build a stash
	   The stash is a storage area that can be reached by simply accessing "Jifty->handler->stash->{some_key}". The stash will start fresh
	   with every request and lives for the entire lifetime of a request. Using the stash, transporting data between otherwise unconnected
	   modules will become possible.

       construct a request and response object
	   Using the CGI object, a Jifty::Request object is constructed and its data is populated with the CGI object's data. The request can be
	   reached later using "Jifty->web->request". The request holds information about all actions involved, all page fragments, contains state
	   variables and arguments (usually GET/POST parameters).

	   Also, an empty Jifty::Response object is constructed that contains one or more Jifty::Result objects, each of which holds one
	   Jifty::Action's result. The response object can be retrieved with the "Jifty->web->response" method.

       setup plugins
	   For every registered Jifty::Plugin, some kind of per-request initialization is performed allowing the actions provided by each plugin
	   to run.

       handle static content
	   If the requested URI points to some existing static content being housed in a "static" directory, this content is handled.

       setup the session
	   Based on a cookie that is sent with every HTTP response, the current user is assigned a unique session. The session is stored in a
	   Jifty::Web::Session object and can be accessed using the "Jifty->web->session" method.

       return from a continuation if requested
	   If there is an open continuation on the stack (e.g. from a "Jifty->web->tangent" link) and the return has been requested (e.g. by a
	   "Jifty->web->return" link), the return will execute at this stage.

       handle dynamic request unless already served
	   First, the user is given a cookie containing the session-id. Then, the request is forwarded to "Jifty->handler->dispatcher", a
	   Jifty::Dispatcher object to handle the request. The dispatcher works through the following steps:

	   setup
	       In this stage, all rules in the dispatcher that are marked with the word "before" are run.

	   run the actions involved
	       Every Jifty::Action that is registered in a form or involved in a link or button is run in this stage.

	   run dispatching rules
	       This stage is responsible for working through all rules marked by words like "under", "on", "when" and so on. This is a point where
	       based on the URI or parameters the template to get displayed may still be modified, data get retrieved, additional actions run or
	       the template's parameters get adjusted.

	   show the page
	       Here, the template displaying the page is run.

	   cleanup
	       This final stage of the dispatcher will run all rules marked with the word "after".

       cleanup several things
	   Finally, the eventually modified session-record is flushed and some internally allocated structures get deallocated.

SEE ALSO

       Jifty::Handler, Jifty::Dispatcher, Jifty::Request, Jifty::Response

perl v5.14.2							    2010-12-08				       Jifty::Manual::RequestHandling(3pm)