I've been researching Zend Framework lately and was curious about what's actually happening behind the scene of the whole dispatch process. I found a wonderful diagram created by Thorsten Ruf (http://nethands.de/download/zenddispatch_en.pdf) Inspired by it's clear and beautifully presented workflow, I decided to go a step deeper and crawl Zend Framework's code. I came up with my own version of the flexible yet complicated workflow. The Zend Framework version is 1.7, noting that things might have changed a bit in the latest 1.8 version that was released a weeks ago.

1. Zend Framework Basic Request Workflow Chart
V 1.01, Created by Polley Wong
End User’s
Browser
Request for a
page
URL
public/index.php
Requires
application/
bootstrap.php
bootstrap.php
Register Custom Plugin
application/
Initializer that runs
$this->initDb();
Runs
Pass in
Configure include Prepares Front $this->initHelpers(); Pass in Optional Custom
Environment
paths Controller $this->initView(); Request & Response
Front Controller
(development/staging/...) $this->initPlugins(); Object
Dispatch
$this->initRoutes();
$this->initControllers();

2. Runs
Front Controller Dispatch Workflow Chart Front Controller
Dispatch
V 1.01, Created by Polley Wong
Front Controller
Register
Instantiate Instantiate Request Object Notify Notify
Default Request Default and Plugin Broker Plugin Broker
Start Routing
Object if none Response Object Response Object of of
provided if none provided with Router Startup Router Completion
Plugin Broker
No
No
Plugin Broker
More Plugins with
More Plugins with Run Plugin’s Run Plugin’s
Yes routeShutdown() Yes
routeStartup() method? routeStartup() routeShutdown()
method?
Find a matching Inject
Extract Module,
Router
route to the returning
Controller, Action
current values to the
and Parameters
PATH_INFO Request Object

3. Runs
Front Controller Dispatch Workflow Chart Front Controller
Dispatch
V 1.01, Created by Polley Wong
Routing Process
Front Controller
Register
Instantiate Instantiate Request Object Notify Notify
Default Request Default and Plugin Broker Plugin Broker
Start Routing
Object if none Response Object Response Object of of
provided if none provided with Router Startup Router Completion cont.
Plugin Broker
No
No
Plugin Broker
More Plugins with
More Plugins with Run Plugin’s Run Plugin’s
Yes routeShutdown() Yes
routeStartup() method? routeStartup() routeShutdown()
method?
Find a matching Inject
Extract Module,
Router
route to the returning
Controller, Action
current values to the
and Parameters
PATH_INFO Request Object

4. Front Controller Dispatch Workflow Chart
V 1.01, Created by Polley Wong
Yes
Replace current Action
Replace current Action OR Skip current action
Front Controller
Skip current action
postDispatch Process
preDispatch Process
Yes
Notify Set Notify Notify
Did any Action Did any
Plugin Broker Request Object'’s Plugin Broker Request Object Plugin Broker
cont. preDispatch() reset Controller postDispatch() reset
of “isDispatched Flag” of No: and of
“isDispatched Flag” Dispatch “isDispatched Flag”
Dispatch Loop to Dispatch Response Object Dispatch
to FALSE? Process to FALSE?
Startup TRUE Startup Completion
cont.
No
Request
Request
Object No Request
Object No
Object
Plugin Broker
More Plugins with More Plugins with More Plugins with
Run Plugin’s Run Plugin’s Run Plugin’s
dispatchLoopStartup() Yes preDispatch() Yes postDispatch() Yes
dispatchLoopStartup() preDispatch() postDispatch()
method? method? method?

5. Front Controller Dispatch Workflow Chart
V 1.01, Created by Polley Wong
Yes
Replace current Action
Replace current Action OR Skip current action
Skip current action
Front Controller
postDispatch Process
preDispatch Process
Yes
Notify Set Notify Notify
Did any Action Did any
Plugin Broker Request Object'’s Plugin Broker Plugin Broker
Request Object
cont. preDispatch() reset Controller postDispatch() reset
of “isDispatched Flag” of No: and of
“isDispatched Flag” Dispatch “isDispatched Flag”
Dispatch Loop to Dispatch Response Object Dispatch
to FALSE? Process to FALSE?
Startup TRUE Startup Completion
cont.
No
Request
Request
Object No Request
Object No
Object
Plugin Broker
More Plugins with More Plugins with More Plugins with
Run Plugin’s Run Plugin’s Run Plugin’s
dispatchLoopStartup() Yes preDispatch() Yes postDispatch() Yes
dispatchLoopStartup() preDispatch() postDispatch()
method? method? method?
Controller Dispatcher
FALSE Append buffered
content into
Response Object’s
Call
Set TRUE body
Action Controller’s
Rretrieve Is parameter Is parameter
Request Object'’s
Load
dispatch() method
Action Method disableOutputBuffering output buffer disableOutputBuffering
“isDispatched Flag”
Controller TRUE
(Passes the
Name from TRUE (default) start TRUE (default)
to
class file
Name of Action
Request Object or FALSE? or FALSE?
TRUE Destroy Action
to the method)
FALSE Controller Object
Controller
Register Notify Is Notify
Action
Run Run
Initialize Action Action Controller Helper Broker “isDispatched Call of the Helper Broker
Action Controller’s Action Controller’s
Helper Broker with of Flag” == Action Method of
preDispatch() postDispatch()
Helper Broker Dispatch Startup TRUE? Dispatch Completion
No
No
Action Helper
No
Run
Broker
Run More Helpers with More Helpers with
More helper in init() method Run Helper’s Run Helper’s
setActionController() preDispatch()
Yes Yes postDispatch() Yes
stack? in preDispatch() postDispatch()
method in helper method? method?
helper

6. Front Controller Dispatch Workflow Chart
V 1.01, Created by Polley Wong
Return the
Response Object
Front Controller
Yes
Notify
Plugin Broker
Is “returnResponse”
of sendResponse()
Flag set to TRUE?
Dispatch Loop
cont.
Completion
Request
Object No
Plugin Broker
More Plugins with
Run Plugin’s
dispatchLoopShutdown() Yes
dispatchLoopShutdown()
method?
postDispatch Process (cont.)
Response Object
Output Body
Send Headers
(echo $content)
End User’s
Browser
Waiting for User Input