Base Class for a RESTful Kohana

gistfile1.aw

<?php defined('SYSPATH') OR die('No direct access allowed.');
class Controller_API extends Controller
{
	/**
	 * @var Object Request Payload
	 */
	protected $_request_payload = NULL;

	/**
	 * @var Object Response Payload
	 */
	protected $_response_payload = NULL;

	/**
	 * @var array Map of HTTP methods -> actions
	 */
	protected $_action_map = array
	(
		Http_Request::POST   => 'post',   // Typically Create..
		Http_Request::GET    => 'get',
		Http_Request::PUT    => 'put',    // Typically Update..
		Http_Request::DELETE => 'delete',
	);

	/**
	 * @var array List of HTTP methods which support body content
	 */
	protected $_methods_with_body_content = array
	(
		Http_Request::POST,
		Http_Request::PUT,
	);

	/**
	 * @var array List of HTTP methods which may be cached
	 */
	protected $_cacheable_methods = array
	(
		Http_Request::GET,
	);

	public function before()
	{
		parent::before();

		$this->_parse_request();
	}

	public function after()
	{
		$this->_prepare_response();

		parent::after();
	}

	/**
	 * Parse the request...
	 */
	protected function _parse_request()
	{
		// Override the method if needed.
		$this->request->method(Arr::get(
			$_SERVER,
			'HTTP_X_HTTP_METHOD_OVERRIDE',
			$this->request->method()
		));

		// Is that a valid method?
		if ( ! isset($this->_action_map[$this->request->method()]))
		{
			// TODO .. add to the if (maybe??) .. method_exists($this, 'action_'.$this->request->method())
			throw new Http_Exception_405(array_keys($this->_action_map),
				'The :method method is not supported. Supported methods are :allowed_methods', array(
				':method'          => $method,
				':allowed_methods' => implode(', ', array_keys($this->_action_map)),
			));
		}

		// Get the basic verb based action..
		$action = $this->_action_map[$this->request->method()];

		// If this is a custom action, lets make sure we use it.
		if ($this->request->action() != '_none')
		{
			$action .= '_'.$this->request->action();
		}

		// If we are acting on a collection, append _collection to the action name.
		if ($this->request->param('id', FALSE) === FALSE)
		{
			$action .= '_collection';
		}

		// Override the action
		$this->request->action($action);

		// Are we be expecting body content as part of the request?
		if (in_array($this->request->method(), $this->_methods_with_body_content))
		{
			$this->_parse_request_body();
		}
	}

	/**
	 * @todo Support more than just JSON
	 */
	protected function _parse_request_body()
	{
		try
		{
			$this->_response_payload = json_decode($this->request->body(), TRUE);

			if ( ! is_array($this->_response_payload) AND ! is_object($this->_response_payload))
				throw new Http_Exception_400('Invalid json supplied. \':json\'', array(
					':json' => $this->request->body(),
				));
		}
		catch (Exception $e)
		{
			throw new Http_Exception_400('Invalid json supplied. \':json\'', array(
				':json' => $this->request->body(),
			));
		}
	}

	protected function _prepare_response()
	{
		// Should we prevent this request from being cached?
		if ( ! in_array($this->request->method(), $this->_cacheable_methods))
		{
			$this->response->headers('cache-control', 'no-cache, no-store, max-age=0, must-revalidate');
		}

		// Set the correct content-type header
		$this->response->headers('Content-Type', 'application/json');

		$this->_prepare_response_body();
	}

	/**
	 * @todo Support more than just JSON
	 */
	protected function _prepare_response_body()
	{
		try
		{
			// Format the reponse as JSON
			$this->response->body(json_encode($this->_response_payload));
		}
		catch (Exception $e)
		{
			throw new Http_Exception_500('Error while formatting response');
		}
	}
}