Controllers¶

What is a controller?¶

A controller is used to manage the logic for a certain section of your application. Most commonly, controllers are used to manage the logic for a single model. For example, if you were building a site that manages a video collection, you might have a VideosController and a RentalsController managing your videos and rentals, respectively. In Cake, controller names are always plural.

Your application’s controllers are classes that extend the Cake AppController class, which in turn extends a core Controller class. Controllers can include any number of actions: functions used in your web application to display views.

The AppController class can be defined in /app/app_controller.php and it should contain methods that are shared between two or more controllers. It itself extends the Controller class which is a standard Cake library.

An action is a single functionality of a controller. It is run automatically by the Dispatcher if an incoming page request specifies it in the routes configuration. Returning to our video collection example, our VideosController might contain the view(), rent(), and search() actions. The controller would be found in /app/controllers/videos_controller.php and contain:

<?php
class VideosController extends AppController
{
    function view($id)
    {
        //action logic goes here..
    }

    function rent($customer_id, $video_id)
    {
        //action logic goes here..
    }

    function search($query)
    {
        //action logic goes here..
    }
}

You would be able to access these actions using the following example URLs:

http://www.example.com/videos/view/253
http://www.example.com/videos/rent/5124/0-235253
http://www.example.com/videos/search/hudsucker+proxy

But how would these pages look? You would need to define a view for each of these actions - check it out in the next chapter, but stay with me: the following sections will show you how to harness the power of the Cake controller and use it to your advantage. Specifically, you’ll learn how to have your controller hand data to the view, redirect the user, and much more.

Controller Functions¶

While this section will treat most of the often-used functions in Cake’s Controller, it’s important to remember to use https://api.cakephp.org for a full reference.

<?php
// Here is our simple controller:

class UsersController extends AppController
{
    function getUserList()
    {
        return $this->User->findAll();
    }
}

<?php
class ProductsController extends AppController
{
    function showUserProducts()
    {
        $this->set('users', $this->requestAction('/users/getUserList'));

        // Now the $users variable in the view will have the data from
        // UsersController::getUserList().
    }
}

<?php
class ProgramsController extends AppController
{
    function viewAll()
    {
        $this->set('userTable', $this->requestAction('/users/getUserList', array('return')));

        // Now, we can echo out $userTable in this action's view to
        // see the rendered view that is also available at /users/getUserList.
    }
}

<?php
// Inside a controller, you can use log() to write entries:
$this->log('Mayday! Mayday!');
//Log entry:
06-03-28 08:06:22 Error: Mayday! Mayday!
$this->log("Looks like {$_SESSION['user']} just logged in.", LOG_DEBUG);
//Log entry:
06-03-28 08:06:22 Debug: Looks like Bobby just logged in.

// app/views/people/search.thtml:
<?php echo $html->input('Person/last_name'); ?>

Array
(
    [Person] => Array
        (
            [last_name] => Anderson
        )
)

<?php
// app/controllers/people_controller.php:
$conditions = $this->postConditions($this->data);

// Yields an array looking like this:
Array
(
    [Person.last_name] => Anderson
)

// Which can be used in model find operations:
$this->Person->findAll($conditions);

Controller Variables¶

Manipulating a few special variables inside of your controller allows you to take advantage of some extra Cake functionality:

$name

PHP 4 doesn’t like to give us the name of the current class in CamelCase. Use this variable to set the correct CamelCased name of your class if you’re running into problems.

$uses

Does your controller use more than one model? Your FragglesController will automatically load $this->Fraggle, but if you want access to $this->Smurf as well, try adding something like the following to your controller:

<?php
var $uses = array('Fraggle','Smurf');

Please notice how you also need to include your Fraggle model in the $uses array, even though it was automatically available before.

$helpers

Use this variable to have your controller load helpers into its views. The HTML helper is automatically loaded, but you can use this variable to specify a few others:

<?php
var $helpers = array('Html','Ajax','Javascript');

Remember that you will need to include the HtmlHelper in the $helpers array if you intend to use it. It is normally available by default, but if you define $helpers without it, you’ll get error messages in your views.

$layout

Set this variable to the name of the layout you would like to use for this controller.

$autoRender

Setting this to false will stop your actions from automatically rendering.

$beforeFilter

If you’d like a bit of code run every time an action is called (and before any of that action code runs), use $beforeFilter. This functionality is really nice for access control - you can check to see a user’s permissions before any action takes place. Just set this variable using an array containing the controller action(s) you’d like to run:

<?php
class ProductsController extends AppController
{
    var $beforeFilter = array('checkAccess');

    function checkAccess()
    {
        //Logic to check user identity and access would go here....
    }

    function index()
    {
        //When this action is called, checkAccess() is called first.
    }
}

$components

Just like $helpers and $uses, this variable is used to load up components you will need:

<?php
var $components = array('acl');

Controller Parameters¶

Controller parameters are available at $this->params in your Cake controller. This variable is used to get data into the controller and provide access to information about the current request. The most common usage of $this->params is to get access to information that has been handed to the controller via POST or GET operations.

$this->data

Used to handle POST data sent from HTML Helper forms to the controller:

<?php
// A HTML Helper is used to create a form element

$html->input('User/first_name');

// When rendered as HTML it looks like:

<input name="data[User][first_name]" value="" type="text" />

// And when submitted to the controller via POST,
// shows up in $this->data['User']['first_name']

Array
(
    [data] => Array
        (
            [User] => Array
                (
                    [username] => mrrogers
                    [password] => myn3ighb0r
                    [first_name] => Mister
                    [last_name] => Rogers
                )

        )
)

$this->params[‘form’]

Any POST data from any form is stored here, including information also found in $_FILES.

$this->params[‘bare’]

Stores ‘1’ if the current layout is bare, ‘0’ if not.

$this->params[‘ajax’]

Stores ‘1’ if the current layout is ajax, ‘0’ if not.

$this->params[‘controller’]

Stores the name of the current controller handling the request. For example, if the URL /posts/view/1 was called, $this->params[‘controller’] would equal “posts”.

$this->params[‘action’]

Stores the name of the current action handling the request. For example, if the URL /posts/view/1 was called, $this->params[‘action’] would equal “view”.

$this->params[‘pass’]

Stores the GET query string passed with the current request. For example, if the URL /posts/view/?var1=3&var2=4 was called, $this->params[‘pass’] would equal “?var1=3&var2=4”.

$this->params[‘url’]

Stores the current URL requested, along with key-value pairs of get variables. For example, if the URL /posts/view/?var1=3&var2=4 was called, $this->params[‘url’] would look like this:

[url] => Array
        (
            [url] => posts/view
            [var1] => 3
            [var2] => 4
        )