Simple, GET-only version of Rails' ActiveResource for CodeIgniter

active_resource_model.php

<?php 
/**
 * Active_resource_model is a simple, GET-only version of Rails' ActiveResource
 * (http://api.rubyonrails.org/classes/ActiveResource/Base.html) for CodeIgniter.
 * 
 * Only JSON data sources are supported at present.  Active_resource_model requires the CodeIgniter "curl" library
 * (http://getsparks.org/packages/curl/show).
 * 
 * Copy this file into application/models and then add "Active_resource_model" to the models array in
 * application/config/autoload.php.
 * 
 * Simply create model classes that extend "Active_resource_model".  You must set the base URL of the data source
 * (the "site" instance variable) in each subclass.  Use Active_resource_model::find_by_id() and/or
 * Active_resource_model::find_all() to fetch records.  Get attributes from instances using "get_<attribute name>".
 * 
 * @author    Dan Bettles <[email protected]>
 * @copyright 2012 Dan Bettles
 * @license   http://www.opensource.org/licenses/MIT MIT
 */

if ( ! defined('BASEPATH')) exit('No direct script access allowed');

/**
 * Active_resource_model
 * 
 * @author Dan Bettles <[email protected]>
 */
class Active_resource_model extends CI_Model {

	/**
	 * The URL of the API.
	 * 
	 * @var string
	 */
	public $site;

	/**
	 * The name of the format of the data that will be requested from the API.
	 * 
	 * @var string
	 */
	public $format = 'json';

	/**
	 * The model's attributes.
	 * 
	 * @var array
	 */
	private $_attributes = array();

	/**
	 * The name of this model in the API.
	 * 
	 * @var string
	 */
	public $element_name;

	/**
	 * __construct()
	 * 
	 * @see parent::__construct
	 */
	public function __construct()
	{
		parent::__construct();

		$this->load->spark('curl/1.2.1');
		$this->load->helper('inflector');
	}

	/**
	 * Returns the object with the specified ID, or throws an exception if the object doesn't exist
	 * 
	 * @param mixed $object_id
	 * 
	 * @return Active_resource
	 * @throws InvalidArgumentException If the ID is invalid
	 * @throws RuntimeException If the object does not exist
	 */
	public function find_by_id($object_id)
	{
		$this->_ensure_id_valid($object_id);

		$api_request_url = $this->_get_api_controller_url() . '/' . $object_id . '.' . $this->_get_format();
		$something = $this->_fetch_json($api_request_url);

		if ($something === FALSE) {
			//@todo Create a more appropriate, custom exception
			throw new RuntimeException('The object does not exist');
		}

		return $something;
	}

	/**
	 * Returns TRUE if the specified ID is valid, or throws an exception otherwise
	 * 
	 * @param mixed $object_id
	 * 
	 * @return bool
	 * @throws InvalidArgumentException If the ID is invalid
	 */
	private function _ensure_id_valid($object_id)
	{
		if ( ! (is_scalar($object_id) AND strlen((string) $object_id)))
		{
			throw new InvalidArgumentException('The ID is invalid');
		}

		return TRUE;
	}

	/**
	 * Returns the name of the API controller corresponding to this model
	 * 
	 * @return string
	 */
	private function _get_api_controller_name()
	{
		$element_name = $this->_get_element_name();

		if (is_string($element_name) AND strlen($element_name)) {
			return plural($element_name);
		}

		return strtolower(plural(preg_replace('/_model$/i', '', get_class($this))));
	}

	/**
	 * Returns the URL of the API, or throws an exception if the URL hasn't been set
	 * 
	 * @return string
	 * @throws RuntimeException The URL of the API has not been set
	 */
	private function _get_site()
	{
		if ( ! strlen($this->site))
		{
			throw new RuntimeException('The URL of the API has not been set');
		}

		return rtrim($this->site, '/');
	}

	/**
	 * Returns the name of the format of the data that will be requested from the API
	 * 
	 * @return string
	 */
	private function _get_format()
	{
		return ltrim($this->format, '.');
	}

	/**
	 * Creates an instance of this class using values in the specified object
	 * 
	 * @param stdClass $plain_object
	 * 
	 * @return Active_resource_model
	 */
	private function _create_instance_from_attrs(stdClass $plain_object)
	{
		$instance = new $this();

		foreach ((array) $plain_object as $attribute_name => $attribute_value) {
			$instance->{"set_{$attribute_name}"}($attribute_value);
		}

		return $instance;
	}

	/**
	 * Provides setters and getters for attributes
	 * 
	 * @param string $method_name Name of the method
	 * @param array  $arguments   Arguments passed to the method
	 * 
	 * @return mixed
	 * @throws RuntimeException If the method does not exist
	 */
	public function __call($method_name, array $arguments)
	{
		$method_supported = (bool) preg_match('/^(set|get)_(.+)/', $method_name, $matches);

		if ( ! $method_supported) {
			throw new RuntimeException('The method does not exist');
		}

		switch ($matches[1]) {
			case 'set':
				$this->_attributes[$matches[2]] = reset($arguments);
				break;

			case 'get':
				return $this->_attributes[$matches[2]];
				break;
		}
	}

	/**
	 * Returns the URL of the API controller corresponding to this model
	 * 
	 * @return string
	 */
	private function _get_api_controller_url()
	{
		return $this->_get_site() . '/' . $this->_get_api_controller_name();
	}

	/**
	 * Returns all objects
	 *
	 * @param array [$arguments = array()]
	 * 
	 * @return array
	 */
	public function find_all(array $arguments = array())
	{
		$api_request_url = $this->_get_api_controller_url() . '.' . $this->_get_format();
		$api_request_url .= $this->_create_api_req_url_query($arguments);

		$something = $this->_fetch_json($api_request_url);

		return $something === FALSE ? array() : $something;
	}

	/**
	 * Returns either a single object or an array of objects, or FALSE if the API returned nothing
	 * 
	 * @param string $api_request_url URL
	 * 
	 * @return mixed
	 */
	private function _fetch_json($api_request_url)
	{
		$json = $this->curl->simple_get($api_request_url);

		if ($json === FALSE) {
			return FALSE;
		}

		$something = json_decode($json);

		if (is_array($something)) {
			$objects = array();
	
			foreach ($something as $plain_object) {
				$objects[] = $this->_create_instance_from_attrs($plain_object);
			}
	
			return $objects;
		}

		return $this->_create_instance_from_attrs($something);
	}

	/**
	 * Creates a query-string for an API request URL from the specified arguments
	 * 
	 * @param array $arguments
	 * 
	 * @return string
	 */
	private function _create_api_req_url_query(array $arguments)
	{
		return empty($arguments) ? '' : '?' . http_build_query($arguments);
	}

	/**
	 * Returns the element name
	 * 
	 * @return string
	 */
	private function _get_element_name()
	{
		return $this->element_name;
	}
}

//Location: ./models/active_resource_model.php
//End of file active_resource_model.php

release_model.php

<?php 
/**
 * Release_model
 * 
 * @author    Dan Bettles <[email protected]>
 * @copyright 2012 Dan Bettles
 * @license   http://www.opensource.org/licenses/MIT MIT
 */

/**
 * Release_model
 * 
 * @author Dan Bettles <[email protected]>
 */
class Release_model extends Active_resource_model {

	/**
	 * Tracks.
	 * 
	 * @var array
	 */
	private $_release_tracks = array();

	/**
	 * __construct
	 */
	public function __construct()
	{
		parent::__construct();

		$archaic_horizon_api_cfg = $this->config->item('archaic_horizon_api', 'app');
		$this->site = $archaic_horizon_api_cfg['site'];
	}

	/**
	 * Scope
	 * 
	 * Returns all releases in reverse chronological order
	 * 
	 * @return array
	 */
	public function history()
	{
		return $this->find_all(array('order' => 'released_at', 'in_reverse' => 1));
	}

	/**
	 * Scope
	 * 
	 * Returns the summary of the latest release or throws an exception otherwise
	 * 
	 * @return Release_model
	 * @throws RuntimeException If there is no latest release
	 */
	public function latest_summary()
	{
		$something = $this->find_all(array(
			'order' => 'released_at',
			'in_reverse' => 1,
			'num_per_page' => 1,
			'page' => 1
		));

		if (empty($something)) {
			throw new RuntimeException('There is no latest release');
		}

		return reset($something);
	}

	/**
	 * Returns the description in HTML format
	 * 
	 * @return string
	 */
	public function get_description_html()
	{
		$this->load->spark('markdown/1.2.0');
		return parse_markdown($this->get_description());
	}

	/**
	 * Fetches the specified release and then fetches its associated objects
	 *
	 * @see parent::find_by_id()
	 */
	public function find_by_id($object_id)
	{
		$release = parent::find_by_id($object_id);
		$release->_fetch_release_tracks();
		return $release;
	}

	/**
	 * _fetch_release_tracks
	 * 
	 * @return void
	 */
	private function _fetch_release_tracks()
	{
		$this->load->model('Release_track_model');

		$this->_release_tracks = $this->Release_track_model->find_all(array(
			'release_code' => $this->get_code(),
			'order' => 'position'
		));
	}

	/**
	 * get_release_tracks
	 * 
	 * @return array
	 */
	public function get_release_tracks()
	{
		return $this->_release_tracks;
	}
}

//Location: ./models/release_model.php
//End of file release_model.php

release_track_model.php

<?php 
/**
 * Release_track_model
 * 
 * @author    Dan Bettles <[email protected]>
 * @copyright 2012 Dan Bettles
 */

/**
 * Release_track_model
 * 
 * @author Dan Bettles <[email protected]>
 */
class Release_track_model extends Active_resource_model {

	/**
	 * __construct
	 */
	public function __construct()
	{
		parent::__construct();

		$archaic_horizon_api_cfg = $this->config->item('archaic_horizon_api', 'app');
		$this->site = $archaic_horizon_api_cfg['site'];

		$this->element_name = 'track';
	}

	/**
	 * Returns the length of the track in an ISO 8601 duration
	 * 
	 * @return string
	 */
	public function get_iso_8601_duration()
	{
		list($minutes, $seconds) = explode(':', $this->get_time(), 2);
		return "PT{$minutes}M{$seconds}S";
	}
}

//Location: ./models/release_track_model.php
//End of file release_track_model.php