A Practical Tutorial Of Zend Framework(二)

Zend_Controller

Using the controller is pretty intuitive. In fact, I'm writing this tutorial without the luxury of documentation!

Note: Documentation is now available at
http://framework.zend.com/manual/zend.controller.html.
I begin with

Zend_Controller_Front

, a front controller. In order to begin understanding how it works, place the following code in your

index.php

file:

<?php

include 'Zend.php';

Zend::loadClass('Zend_Controller_Front');

$controller = Zend_Controller_Front::getInstance();
$controller->setControllerDirectory('/path/to/controllers');
$controller->dispatch();

?>

If you prefer object chaining, this can instead be written as:

<?php

include 'Zend.php';

Zend::loadClass('Zend_Controller_Front');

$controller = Zend_Controller_Front::getInstance()
->setControllerDirectory('/path/to/controllers')
->dispatch();

?>

Now when you make a request for

/foo/bar

, you get an error. That's good! It lets you know something is happening. The major complaint is that

IndexController.php

is not found. Before you create this file, it's helpful to understand how the framework expects you to organize things. The framework breaks a request down into parts, and in the case of a request for

/foo/bar

,

foo

is the controller, and

bar

is the action. The default value for each is

index

. When

foo

is the controller, the framework looks for a file called

FooController.php

in the

controllers

directory. Because this does not exist, the framework falls back to

IndexController.php

. Not finding either, it reports the error. To continue, create

IndexController.php

in the

controllers

directory (which you set with

setControllerDirectory()

):

<?php

Zend::loadClass('Zend_Controller_Action');

class IndexController extends Zend_Controller_Action
{
public function indexAction()
{
echo 'IndexController::indexAction()';
}
}

?>

The

IndexController

class handles requests for which the controller is

index

or for which the indicated controller does not exist, as just explained. The

indexAction()

method handles requests for which the action is

index

. Remember that

index

is the default value for both the controller and the action. If you try a request for

/

,

/index

, or

/index/index

, the

indexAction()

method is executed. (Trailing slashes do not alter this behavior.) A request for any other resource is going to result in an error. There is another useful method to add to

IndexController

before continuing. The

noRouteAction()

method is called whenever a request is made for a controller that doesn't exist. For example, a request for

/foo/bar

executes

noRouteAction()

if

FooController.php

does not exist. However, a request for

/index/foo

still results in an error, because

foo

is the action, not the controller. Add

noRouteAction()

to

IndexController.php

:

<?php

Zend::loadClass('Zend_Controller_Action');

class IndexController extends Zend_Controller_Action
{
public function indexAction()
{
echo 'IndexController::indexAction()';
}

public function noRouteAction()
{
$this->_redirect('/');
}
}

?>

This example uses

$this->_redirect('/')

to illustrate a possible action to take in

noRouteAction()

. This causes requests for nonexistent controllers to be redirected to the root document (front page). Now create

FooController.php

:

<?php

Zend::loadClass('Zend_Controller_Action');

class FooController extends Zend_Controller_Action
{
public function indexAction()
{
echo 'FooController::indexAction()';
}

public function barAction()
{
echo 'FooController::barAction()';
}
}

?>

If you again request

/foo/bar

, you should see that

barAction()

is being executed, because

bar

is the action. Not only can you already support friendly URLs, but you can also do so in a very organized way with just a few lines of code. Cool! You can also create a

__call()

method to handle requests for undefined actions such as

/foo/baz

:

<?php

Zend::loadClass('Zend_Controller_Action');

class FooController extends Zend_Controller_Action
{
public function indexAction()
{
echo 'FooController::indexAction()';
}

public function barAction()
{
echo 'FooController::barAction()';
}

public function __call($action, $arguments)
{
echo 'FooController:__call()';
}
}

?>

Now that you can elegantly handle incoming requests with just a few lines of code, you are ready to continue.