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Controllers

Controllers are the ‘C’ in MVC. After routing has been applied and the correct controller has been found, your controller’s action is called. Your controller should handle interpreting the request data, making sure the correct models are called, and the right response or view is rendered. Controllers can be thought of as middle man between the Model and View. You want to keep your controllers thin, and your models fat. This will help you more easily reuse your code and makes your code easier to test.

Commonly, controllers are used to manage the logic around a single model. For example, if you were building a site for an on-line bakery, you might have a RecipesController and an IngredientsController managing your recipes and their ingredients. In CakePHP, controllers are named after the primary model they handle. It’s totally possible to have controllers work with more than one model as well.

Your application’s controllers extend AppController class, which in turn extends the core Controller class. The AppController class can be defined in /app/Controller/AppController.php and it should contain methods that are shared between all of your application’s controllers.

Controllers provide a number of methods which are called actions. Actions are methods on a controller that handle requests. By default all public methods on a controller are an action, and accessible from a url. Actions are responsible for interpreting the request and creating the response. Usually responses are in the form of a rendered view, but there are other ways to create responses as well.

The App Controller

As stated in the introduction, the AppController class is the parent class to all of your application’s controllers. AppController itself extends the Controller class included in the CakePHP core library. As such, AppController is defined in /app/Controller/AppController.php like so:

<?php
class AppController extends Controller {
}

Controller attributes and methods created in your AppController will be available to all of your application’s controllers. It is the ideal place to create code that is common to all of your controllers. Components (which you’ll learn about later) are best used for code that is used in many (but not necessarily all) controllers.

While normal object-oriented inheritance rules apply, CakePHP does a bit of extra work when it comes to special controller attributes. The list of components and helpers used by a controller are treated specially. In these cases, AppController value arrays are merged with child controller class arrays. The values in the child class will always override those in AppController.

Note

CakePHP merges the following variables from the AppController to your application’s controllers:

  • $components
  • $helpers
  • $uses

Remember to add the default Html and Form helpers, if you define var $helpers in your AppController

Please also remember to call AppController’s callbacks within child controller callbacks for best results:

<?php
public function beforeFilter() {
    parent::beforeFilter();
}

Request parameters

When a request is made to a CakePHP application, CakePHP’s Router and Dispatcher classes use Routes Configuration to find and create the correct controller. The request data is encapsulated into a request object. CakePHP puts all of the important request information into the $this->request property. See the section on CakeRequest for more information on the CakePHP request object.

Controller actions

Controller actions are responsible for converting the request parameters into a response for the browser/user making the request. CakePHP uses conventions to automate this process and remove some boiler-plate code you would otherwise need to write.

By convention CakePHP renders a view with an inflected version of the action name. Returning to our online bakery example, our RecipesController might contain the view(), share(), and search() actions. The controller would be found in /app/Controller/RecipesController.php and contain:

<?php
# /app/Controller/RecipesController.php

class RecipesController extends AppController {
    public function view($id) {
        //action logic goes here..
    }

    public function share($customerId, $recipeId) {
        //action logic goes here..
    }

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

The view files for these actions would be app/View/Recipes/view.ctp, app/View/Recipes/share.ctp, and app/View/Recipes/search.ctp. The conventional view file name is the lower cased and underscored version of the action name.

Controller actions generally use set() to create a context that View uses to render the view. Because of the conventions that CakePHP uses, you don’ need to create and render the view manually. Instead once a controller action has completed, CakePHP will handle rendering and delivering the View.

If for some reason you’d like to skip the default behavior. Both of the following techniques will by-pass the default view rendering behavior.

  • If you return a string, or an object that can be converted to a string from your controller action, it will be used as the response body.
  • You can return a CakeResponse object with the completely created response.

When controller methods are used with requestAction() you will often want to return data that isn’t a string. If you have controller methods that are used for normal web requests + requestAction you should check the request type before returning:

<?php
class RecipesController extends AppController {
    public function popular() {
        $popular = $this->Recipe->popular();
        if (!empty($this->request->params['requested'])) {
            return $popular;
        }
        $this->set('popular', $popular);
    }
}

The above controller action is an example of how a method can be used with requestAction() and normal requests. Returning an array data to a non-requestAction request will cause errors and should be avoided. See the section on Controller::requestAction() for more tips on using requestAction()

In order for you to use a controller effectively in your own application, we’ll cover some of the core attributes and methods provided by CakePHP’s controllers.

Request Life-cycle callbacks

class Controller

CakePHP controllers come fitted with callbacks you can use to insert logic around the request life-cycle:

Controller::beforeFilter()

This function is executed before every action in the controller. It’s a handy place to check for an active session or inspect user permissions.

Note

The beforeFilter() method will be called for missing actions, and scaffolded actions.

Controller::beforeRender()

Called after controller action logic, but before the view is rendered. This callback is not used often, but may be needed if you are calling render() manually before the end of a given action.

Controller::afterFilter()

Called after every controller action, and after rendering is complete. This is the last controller method to run.

In addition to controller life-cycle callbacks, Components also provide a similar set of callbacks.

Controller Methods

For a complete list of controller methods and their descriptions visit the CakePHP API. Check out http://api20.cakephp.org/class/controller.

Interacting with Views

Controllers interact with the view in a number of ways. First they are able to pass data to the views, using set(). You can also decide which view class to use, and which view file should be rendered from the controller.

Controller::set(string $var, mixed $value)

The set() method is the main way to send data from your controller to your view. Once you’ve used set(), the variable can be accessed in your view:

<?php
// First you pass data from the controller:

$this->set('color', 'pink');

// Then, in the view, you can utilize the data:
?>

You have selected <?php echo $color; ?> icing for the cake.

The set() method also takes an associative array as its first parameter. This can often be a quick way to assign a set of information to the view.

Changed in version 1.3: Array keys will no longer be inflected before they are assigned to the view (‘underscored_key’ does not become ‘underscoredKey’ anymore, etc.):

<?php
$data = array(
    'color' => 'pink',
    'type' => 'sugar',
    'base_price' => 23.95
);

// make $color, $type, and $base_price
// available to the view:

$this->set($data);

The attribute $pageTitle no longer exists, use set() to set the title:

<?php
$this->set('title_for_layout', 'This is the page title');
Controller::render(string $action, string $layout, string $file)

The render() method is automatically called at the end of each requested controller action. This method performs all the view logic (using the data you’ve given in using the set() method), places the view inside its layout and serves it back to the end user.

The default view file used by render is determined by convention. If the search() action of the RecipesController is requested, the view file in /app/View/Recipes/search.ctp will be rendered:

<?php
class RecipesController extends AppController {
// ...
    public function search() {
        // Render the view in /View/Recipes/search.ctp
        $this->render();
    }
// ...
}

Although CakePHP will automatically call it (unless you’ve set $this->autoRender to false) after every action’s logic, you can use it to specify an alternate view file by specifying an action name in the controller using $action.

If $action starts with ‘/’ it is assumed to be a view or element file relative to the /app/View folder. This allows direct rendering of elements, very useful in ajax calls.

<?php
// Render the element in /View/Elements/ajaxreturn.ctp
$this->render('/Elements/ajaxreturn');

You can also specify an alternate view or element file using the third parameter, $file. The $layout parameter allows you to specify the layout the view is rendered in.

Rendering a specific view

In your controller you may want to render a different view than what would conventionally be done. You can do this by calling render() directly. Once you have called render() CakePHP will not try to re-render the view:

<?php
class PostsController extends AppController {
    public function my_action() {
        $this->render('custom_file');
    }
}

This would render app/View/Posts/custom_file.ctp instead of app/View/Posts/my_action.ctp

Flow Control

Controller::redirect(mixed $url, integer $status, boolean $exit)

The flow control method you’ll use most often is redirect(). This method takes its first parameter in the form of a CakePHP-relative URL. When a user has successfully placed an order, you might wish to redirect them to a receipt screen.:

<?php
public function place_order() {
    // Logic for finalizing order goes here
    if ($success) {
        $this->redirect(array('controller' => 'orders', 'action' => 'thanks'));
    } else {
        $this->redirect(array('controller' => 'orders', 'action' => 'confirm'));
    }
}

You can also use a relative or absolute URL as the $url argument:

<?php
$this->redirect('/orders/thanks'));
$this->redirect('http://www.example.com');

You can also pass data to the action:

<?php
$this->redirect(array('action' => 'edit', $id));

The second parameter of redirect() allows you to define an HTTP status code to accompany the redirect. You may want to use 301 (moved permanently) or 303 (see other), depending on the nature of the redirect.

The method will issue an exit() after the redirect unless you set the third parameter to false.

If you need to redirect to the referer page you can use:

<?php
$this->redirect($this->referer());

The method also supports name based parameters. If you want to redirect to a URL like: http://www.example.com/orders/confirm/product:pizza/quantity:5 you can use:

<?php
$this->redirect(array('controller' => 'orders', 'action' => 'confirm', 'product' => 'pizza', 'quantity' => 5));
Controller::flash(string $message, string $url, integer $pause, string $layout)

Like redirect(), the flash() method is used to direct a user to a new page after an operation. The flash() method is different in that it shows a message before passing the user on to another URL.

The first parameter should hold the message to be displayed, and the second parameter is a CakePHP-relative URL. CakePHP will display the $message for $pause seconds before forwarding the user on.

If there’s a particular template you’d like your flashed message to use, you may specify the name of that layout in the $layout parameter.

For in-page flash messages, be sure to check out SessionComponent’s setFlash() method.

Callbacks

In addition to the Request Life-cycle callbacks. CakePHP also supports callbacks related to scaffolding.

Controller::beforeScaffold($method)

$method name of method called example index, edit, etc.

Controller::afterScaffoldSave($method)

$method name of method called either edit or update.

Controller::afterScaffoldSaveError($method)

$method name of method called either edit or update.

Controller::scaffoldError($method)

$method name of method called example index, edit, etc.

Other Useful Methods

Controller::constructClasses()

This method loads the models required by the controller. This loading process is done by CakePHP normally, but this method is handy to have when accessing controllers from a different perspective. If you need CakePHP in a command-line script or some other outside use, constructClasses() may come in handy.

Controller::referer(mixed $default = null, boolean $local = false)

Returns the referring URL for the current request. Parameter $default can be used to supply a default URL to use if HTTP_REFERER cannot be read from headers. So, instead of doing this:

<?php
class UserController extends AppController {
    public function delete($id) {
        // delete code goes here, and then...
        if ($this->referer() != '/') {
            $this->redirect($this->referer());
        } else {
            $this->redirect(array('action' => 'index'));
        }
    }
}

you can do this:

<?php
class UserController extends AppController {
    public function delete($id) {
        // delete code goes here, and then...
        $this->redirect($this->referer(array('action' => 'index')));
    }
}

If $default is not set, the function defaults to the root of your domain - ‘/’.

Parameter $local if set to true, restricts referring URLs to local server.

Controller::disableCache()

Used to tell the user’s browser not to cache the results of the current request. This is different than view caching, covered in a later chapter.

The headers sent to this effect are:

Expires: Mon, 26 Jul 1997 05:00:00 GMT
Last-Modified: [current datetime] GMT
Cache-Control: no-store, no-cache, must-revalidate
Cache-Control: post-check=0, pre-check=0
Pragma: no-cache
Controller::postConditions(array $data, mixed $op, string $bool, boolean $exclusive)

Use this method to turn a set of POSTed model data (from HtmlHelper-compatible inputs) into a set of find conditions for a model. This function offers a quick shortcut on building search logic. For example, an administrative user may want to be able to search orders in order to know which items need to be shipped. You can use CakePHP’s FormHelper and HtmlHelper to create a quick form based on the Order model. Then a controller action can use the data posted from that form to craft find conditions:

<?php
public function index() {
    $conditions = $this->postConditions($this->request->data);
    $orders = $this->Order->find('all', compact('conditions'));
    $this->set('orders', $orders);
}

If $this->request->data['Order']['destination'] equals “Old Towne Bakery”, postConditions converts that condition to an array compatible for use in a Model->find() method. In this case, array('Order.destination' => 'Old Towne Bakery').

If you want to use a different SQL operator between terms, supply them using the second parameter:

<?php
/*
Contents of $this->request->data
array(
    'Order' => array(
        'num_items' => '4',
        'referrer' => 'Ye Olde'
    )
)
*/

// Let's get orders that have at least 4 items and contain 'Ye Olde'
$conditions = $this->postConditions(
    $this->request->data,
    array(
        'num_items' => '>=',
        'referrer' => 'LIKE'
    )
);
$orders = $this->Order->find('all', compact('conditions'));

The third parameter allows you to tell CakePHP what SQL boolean operator to use between the find conditions. Strings like ‘AND’, ‘OR’ and ‘XOR’ are all valid values.

Finally, if the last parameter is set to true, and the $op parameter is an array, fields not included in $op will not be included in the returned conditions.

Controller::paginate()

This method is used for paginating results fetched by your models. You can specify page sizes, model find conditions and more. See the pagination section for more details on how to use paginate.

Controller::requestAction(string $url, array $options)

This function calls a controller’s action from any location and returns data from the action. The $url passed is a CakePHP-relative URL (/controllername/actionname/params). To pass extra data to the receiving controller action add to the $options array.

Note

You can use requestAction() to retrieve a fully rendered view by passing ‘return’ in the options: requestAction($url, array('return'));. It is important to note that making a requestAction using ‘return’ from a controller method can cause script and css tags to not work correctly.

Warning

If used without caching requestAction can lead to poor performance. It is rarely appropriate to use in a controller or model.

requestAction is best used in conjunction with (cached) elements – as a way to fetch data for an element before rendering. Let’s use the example of putting a “latest comments” element in the layout. First we need to create a controller function that will return the data:

<?php
// Controller/CommentsController.php
class CommentsController extends AppController {
    public function latest() {
        if (empty($this->request->params['requested'])) {
            throw new ForbiddenException();
        }
        return $this->Comment->find('all', array('order' => 'Comment.created DESC', 'limit' => 10));
    }
}

You should always include checks to make sure your requestAction methods are actually originating from requestAction. Failing to do so will allow requestAction methods to be directly accessible from a URL, which is generally undesirable.

If we now create a simple element to call that function:

<?php
// View/Elements/latest_comments.ctp

$comments = $this->requestAction('/comments/latest');
foreach ($comments as $comment) {
    echo $comment['Comment']['title'];
}

We can then place that element anywhere to get the output using:

<?php
echo $this->element('latest_comments');

Written in this way, whenever the element is rendered, a request will be made to the controller to get the data, the data will be processed, and returned. However in accordance with the warning above it’s best to make use of element caching to prevent needless processing. By modifying the call to element to look like this:

<?php
echo $this->element('latest_comments', array('cache' => '+1 hour'));

The requestAction call will not be made while the cached element view file exists and is valid.

In addition, requestAction now takes array based cake style urls:

<?php
echo $this->requestAction(
    array('controller' => 'articles', 'action' => 'featured'),
    array('return')
);

This allows the requestAction call to bypass the usage of Router::url which can increase performance. The url based arrays are the same as the ones that HtmlHelper::link() uses with one difference - if you are using named or passed parameters, you must put them in a second array and wrap them with the correct key. This is because requestAction merges the named args array (requestAction’s 2nd parameter) with the Controller::params member array and does not explicitly place the named args array into the key ‘named’; Additional members in the $option array will also be made available in the requested action’s Controller::params array:

<?php
echo $this->requestAction('/articles/featured/limit:3');
echo $this->requestAction('/articles/view/5');

As an array in the requestAction would then be:

<?php
echo $this->requestAction(
    array('controller' => 'articles', 'action' => 'featured'),
    array('named' => array('limit' => 3))
);

echo $this->requestAction(
    array('controller' => 'articles', 'action' => 'view'),
    array('pass' => array(5))
);

Note

Unlike other places where array urls are analogous to string urls, requestAction treats them differently.

When using an array url in conjunction with requestAction() you must specify all parameters that you will need in the requested action. This includes parameters like $this->request->data. In addition to passing all required parameters, named and pass parameters must be done in the second array as seen above.

Controller::loadModel(string $modelClass, mixed $id)

The loadModel function comes handy when you need to use a model which is not the controller’s default model or its associated model:

<?php
$this->loadModel('Article');
$recentArticles = $this->Article->find('all', array('limit' => 5, 'order' => 'Article.created DESC'));

$this->loadModel('User', 2);
$user = $this->User->read();

Controller Attributes

For a complete list of controller attributes and their descriptions visit the CakePHP API. Check out http://api20.cakephp.org/class/controller.

property Controller::$name

The $name attribute should be set to the name of the controller. Usually this is just the plural form of the primary model the controller uses. This property is not required, but saves CakePHP from inflecting it:

<?php
// $name controller attribute usage example
class RecipesController extends AppController {
   public $name = 'Recipes';
}

$components, $helpers and $uses

The next most often used controller attributes tell CakePHP what helpers, components, and models you’ll be using in conjunction with the current controller. Using these attributes make MVC classes given by $components and $uses available to the controller as class variables ($this->ModelName, for example) and those given by $helpers to the view as an object reference variable ($this->{$helpername}).

Note

Each controller has some of these classes available by default, so you may not need to configure your controller at all.

property Controller::$uses

Controllers have access to their primary model available by default. Our RecipesController will have the Recipe model class available at $this->Recipe, and our ProductsController also features the Product model at $this->Product. However, when allowing a controller to access additional models through the $uses variable, the name of the current controller’s model must also be included. This is illustrated in the example below.

If you do not wish to use a Model in your controller, set public $uses = array(). This will allow you to use a controller without a need for a corresponding Model file. However, the models defined in the AppController will still be loaded. You can also use false to not load any models at all. Even those defined in the AppController

Changed in version 2.1: Uses now has a new default value, it also handles false differently.

property Controller::$helpers

The Html, Form, and Session Helpers are available by default, as is the SessionComponent. But if you choose to define your own $helpers array in AppController, make sure to include Html and Form if you want them still available by default in your Controllers. To learn more about these classes, be sure to check out their respective sections later in this manual.

Let’s look at how to tell a CakePHP controller that you plan to use additional MVC classes:

<?php
class RecipesController extends AppController {
    public $uses = array('Recipe', 'User');
    public $helpers = array('Js');
    public $components = array('RequestHandler');
}

Each of these variables are merged with their inherited values, therefore it is not necessary (for example) to redeclare the Form helper, or anything that is declared in your App controller.

property Controller::$components

The components array allows you to set which Components a controller will use. Like $helpers and $uses components in your controllers are merged with those in AppController. As with $helpers you can pass settings into components. See Configuring Components for more information.

Other Attributes

While you can check out the details for all controller attributes in the API, there are other controller attributes that merit their own sections in the manual.