lithium\action\Controller

class

The Controller class is the fundamental building block of your application's request/response cycle. Controllers are organized around a single logical entity, usually one or more model classes (i.e. lithium\data\Model) and are tasked with performing operations against that entity.

Each controller has a series of 'actions' which are defined as class methods of the Controller classes. Each action has a specific responsibility, such as listing a set of objects, updating an object, or deleting an object.

A controller object is instantiated by the Dispatcher (lithium\action\Dispatcher), and is given an instance of the lithium\action\Request class, which contains all necessary request state, including routing information, GET & POST data, and server variables. The controller is then invoked (using PHP's magic __invoke() syntax), and the proper action is called, according to the routing information stored in the Request object.

A controller then returns a response (i.e. using redirect() or render()) which includes HTTP headers, and/or a serialized data response (JSON or XML, etc.) or HTML webpage.

For more information on returning serialized data responses for web services, or manipulating template rendering from within your controllers, see the settings in $_render and the lithium\net\http\Media class.

Source

class Controller extends \lithium\core\Object {

	use \lithium\core\MergeInheritable;

	/**
	 * Contains an instance of the `Request` object with all the details of the HTTP request that
	 * was dispatched to the controller object. Any parameters captured in routing, such as
	 * controller or action name are accessible as properties of this object, i.e.
	 * `$this->request->controller` or `$this->request->action`.
	 *
	 * @see lithium\action\Request
	 * @var object
	 */
	public $request = null;

	/**
	 * Contains an instance of the `Response` object which aggregates the headers and body content
	 * to be written back to the client (browser) when the result of the request is rendered.
	 *
	 * @see lithium\action\Response
	 * @var object
	 */
	public $response = null;

	/**
	 * Lists the rendering control options for responses generated by this controller.
	 *
	 * - The `'type'` key is the content type that will be rendered by default, unless another is
	 *   explicitly specified (defaults to `'html'`).
	 * - The `'data'` key contains an associative array of variables to be sent to the view,
	 *   including any variables created in `set()`, or if an action returns any variables (as an
	 *   associative array).
	 * - When an action is invoked, it will by default attempt to render a response, set the
	 *   `'auto'` key to `false` to prevent this behavior.
	 * - If you manually call `render()` within an action, the `'hasRendered'` key stores this
	 *   state, so that responses are not rendered multiple times, either manually or automatically.
	 * - The `'layout'` key specifies the name of the layout to be used (defaults to `'default'`).
	 *   Typically, layout files are looked up as
	 *   `<app-path>/views/layouts/<layout-name>.<type>.php`. Based on the default settings, the
	 *   actual path would be `path-to-app/views/layouts/default.html.php`.
	 * - Though typically introspected from the action that is executed, the `'template'` key can be
	 *   manually specified. This sets the template to be rendered, and is looked up (by default) as
	 *   `<app-path>/views/<controller>/<action>.<type>.php`, i.e.:
	 *   `path-to-app/views/posts/index.html.php`.
	 * - To enable automatic content-type negotiation (i.e. determining the content type of the
	 *   response based on the value of the
	 *   [HTTP Accept header](http://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html)), set the
	 *   `'negotiate'` flag to `true`. Otherwise, the response will only be based on the `type`
	 *   parameter of the request object (defaulting to `'html'` if no type is present in the
	 *   `Request` parameters).
	 *
	 * Keep in mind that most of these settings may be passed to `Controller::render()` as well. To
	 * change how these settings operate (i.e. template paths, default render settings for
	 * individual media types), see the `Media` class.
	 *
	 * @var array
	 * @see lithium\action\Controller::render()
	 * @see lithium\net\http\Media::type()
	 * @see lithium\net\http\Media::render()
	 */
	protected $_render = [
		'type'        => null,
		'data'        => [],
		'auto'        => true,
		'layout'      => 'default',
		'template'    => null,
		'hasRendered' => false,
		'negotiate'   => false
	];

	/**
	 * Lists `Controller`'s class dependencies. For details on extending or replacing a class,
	 * please refer to that class's API.
	 *
	 * @var array
	 */
	protected $_classes = [
		'media' => 'lithium\net\http\Media',
		'router' => 'lithium\net\http\Router',
		'response' => 'lithium\action\Response'
	];

	/**
	 * Auto configuration properties.
	 *
	 * @var array
	 */
	protected $_autoConfig = ['render' => 'merge', 'classes' => 'merge'];

	/**
	 * Constructor.
	 *
	 * @see lithium\action\Controller::$request
	 * @see lithium\action\Controller::$response
	 * @see lithium\action\Controller::$_render
	 * @see lithium\action\Controller::$_classes
	 * @param array $config Available configuration options are:
	 *        - `'request'` _object|null_: Either a request object or `null`.
	 *        - `'response'` _array_: Options for constructing the response object.
	 *        - `'render'` _array_: Rendering control options.
	 *        - `'classes'` _array_
	 * @return void
	 */
	public function __construct(array $config = []) {
		$defaults = [
			'request' => null, 'response' => [], 'render' => [], 'classes' => []
		];
		parent::__construct($config + $defaults);
	}

	/**
	 * Populates the `$response` property with a new instance of the `Response` class passing it
	 * configuration, and sets some rendering options, depending on the incoming request.
	 *
	 * @return void
	 */
	protected function _init() {
		parent::_init();

		$this->_inherit(['_render']);

		$this->request = $this->request ?: $this->_config['request'];
		$this->response = $this->_instance('response', $this->_config['response']);

		if (!$this->request || $this->_render['type']) {
			return;
		}
		if ($this->_render['negotiate']) {
			$this->_render['type'] = $this->request->accepts();
			return;
		}
		$this->_render['type'] = $this->request->get('params:type') ?: 'html';
	}

	/**
	 * Called by the Dispatcher class to invoke an action.
	 *
	 * @param object $request The request object with URL and HTTP info for dispatching this action.
	 * @param array $dispatchParams The array of parameters that will be passed to the action.
	 * @param array $options The dispatch options for this action.
	 * @return object Returns the response object associated with this controller.
	 * @filter Filter to execute logic before an action is invoked (i.e. custom access
	 *         control) or after it has been called and has returned its response (i.e.
	 *         for caching it).
	 */
	public function __invoke($request, $dispatchParams, array $options = []) {
		$params = compact('request', 'dispatchParams', 'options');

		return Filters::run($this, __FUNCTION__, $params, function($params) {
			$dispatchParams = $params['dispatchParams'];

			$action = isset($dispatchParams['action']) ? $dispatchParams['action'] : 'index';
			$args = isset($dispatchParams['args']) ? $dispatchParams['args'] : [];

			if (substr($action, 0, 1) === '_' || method_exists(__CLASS__, $action)) {
				throw new DispatchException('Attempted to invoke a private method.');
			}
			if (!method_exists($this, $action)) {
				throw new DispatchException("Action `{$action}` not found.");
			}
			$this->_render['template'] = $this->_render['template'] ?: $action;

			if ($result = $this->invokeMethod($action, $args)) {
				if (is_string($result)) {
					$this->render(['text' => $result]);
					return $this->response;
				}
				if (is_array($result)) {
					$this->set($result);
				}
			}

			if (!$this->_render['hasRendered'] && $this->_render['auto']) {
				$this->render();
			}
			return $this->response;
		});
	}

	/**
	 * This method is used to pass along any data from the controller to the view and layout
	 *
	 * @param array $data sets of `<variable name> => <variable value>` to pass to view layer.
	 * @return void
	 */
	public function set($data = []) {
		$this->_render['data'] = (array) $data + $this->_render['data'];
	}

	/**
	 * Uses results (typically coming from a controller action) to generate content and headers for
	 * a `Response` object.
	 *
	 * @see lithium\action\Controller::$_render
	 * @param array $options An array of options, as follows:
	 *        - `'data'`: An associative array of variables to be assigned to the template. These
	 *          are merged on top of any variables set in `Controller::set()`.
	 *        - `'head'`: If true, only renders the headers of the response, not the body. Defaults
	 *          to `false`.
	 *        - `'template'`: The name of a template, which usually matches the name of the action.
	 *          By default, this template is looked for in the views directory of the current
	 *          controller, i.e. given a `PostsController` object, if template is set to `'view'`,
	 *          the template path would be `views/posts/view.html.php`. Defaults to the name of the
	 *          action being rendered.
	 *          The options specified here are merged with the values in the `Controller::$_render`
	 *          property. You may refer to it for other options accepted by this method.
	 * @return object Returns the `Response` object associated with this `Controller` instance.
	 */
	public function render(array $options = []) {
		$media = $this->_classes['media'];
		$class = get_class($this);
		$name = preg_replace('/Controller$/', '', substr($class, strrpos($class, '\\') + 1));
		$key = key($options);

		if (isset($options['data'])) {
			$this->set($options['data']);
			unset($options['data']);
		}
		$defaults = [
			'status'     => null,
			'location'   => false,
			'data'       => null,
			'head'       => false,
			'controller' => Inflector::underscore($name),
			'library'    => Libraries::get($class)
		];

		$options += $this->_render + $defaults;

		if ($key && $media::type($key)) {
			$options['type'] = $key;
			$this->set($options[$key]);
			unset($options[$key]);
		}

		$this->_render['hasRendered'] = true;
		$this->response->type($options['type']);
		$this->response->status($options['status']);
		$this->response->headers('Location', $options['location']);

		if ($options['head']) {
			return;
		}
		$response = $media::render($this->response, $this->_render['data'], $options + [
			'request' => $this->request
		]);
		return ($this->response = $response ?: $this->response);
	}

	/**
	 * Creates a redirect response by calling `render()` and providing a `'location'` parameter.
	 *
	 * @see lithium\net\http\Router::match()
	 * @see lithium\action\Controller::$response
	 * @param mixed $url The location to redirect to, provided as a string relative to the root of
	 *              the application, a fully-qualified URL, or an array of routing parameters to be
	 *              resolved to a URL. Post-processed by `Router::match()`.
	 * @param array $options Options when performing the redirect. Available options include:
	 *              - `'status'` _integer_: The HTTP status code associated with the redirect.
	 *                Defaults to `302`.
	 *              - `'head'` _boolean_: Determines whether only headers are returned with the
	 *                response. Defaults to `true`, in which case only headers and no body are
	 *                returned. Set to `false` to render a body as well.
	 *              - `'exit'` _boolean_: Exit immediately after rendering. Defaults to `false`.
	 *                Because `redirect()` does not exit by default, you should always prefix calls
	 *                with a `return` statement, so that the action is always immediately exited.
	 * @return object Returns the instance of the `Response` object associated with this controller.
	 * @filter Allows to intercept redirects, either stopping them completely i.e. during debugging
	 *         or for logging purposes.
	 */
	public function redirect($url, array $options = []) {
		$defaults = ['location' => null, 'status' => 302, 'head' => true, 'exit' => false];
		$options += $defaults;
		$params = compact('url', 'options');

		Filters::run($this, __FUNCTION__, $params, function($params) {
			$router = $this->_classes['router'];

			$options = $params['options'];
			$location = $options['location'] ?: $router::match($params['url'], $this->request);
			$this->render(compact('location') + $options);
		});

		if ($options['exit']) {
			$this->response->render();
			$this->_stop();
		}
		return $this->response;
	}

	/**
	 * Exit immediately. Primarily used for overrides during testing.
	 *
	 * @param integer|string $status integer range 0 to 254, string printed on exit
	 * @return void
	 */
	protected function _stop($status = 0) {
		exit($status);
	}
}