ogp.php

## ogp.php
<?php
/**
 * Ogp Helper class file
 *
 * Adds OGP elements in <head />
 *
 * Licensed under The MIT License
 *
 * @author        Masunaga Ray (http://www.msng.info/)
 * @link          http://www.msng.info/archives/2011/12/cakephp-ogp-helper.php
 * @license       MIT License (http://www.opensource.org/licenses/mit-license.php)
 */
class OgpHelper extends AppHelper
{
	public $helpers = array('Html');

/**
 * Decides whether or not each property should be taken automatically
 *
 * Works only when the property is not configured anywhere.
 **/
	public $autoGetUrl = true;
	public $autoGetTitle = true;
	public $autoGetSiteName = true;
	public $autoGetLocale = true;

/**
 * Names for configurations
 **/
	public $configName = 'OGP';
	public $configLocaleName = 'OGPlocales';
	public $varName = 'ogp_params';

/**
 * Default values for OGP are read from this property,
 * Configure::read['OGP'] and View variable $ogp_params (by default)
 * and the former is overwritten by the latter.
 * Set to false to skip adding the property.
 **/
	public $defaults = array(
		'fb:admins'      => false,
		'fb:app_id'      => false,
		'og:url'         => false,
		'og:type'        => 'website',
		'og:title'       => false,
		'og:locale'      => false,
		'og:site_name'   => false,
		'og:image'       => false,
		'og:description' => false,
	);

/**
 * Map for CakePHP's config.language with Facebook's locale code
 * used by _getLocale method.
 *
 * Since they can not be associated one to one,
 * these values are supposed to be overwritten by Configure::write('OGPlocales').
 **/
	public $locales = array(
		'ja' => 'ja_JP',
		'en' => 'en_US',
	);

/**
 * Namespace attributes for OGP and Facebook
 **/
	protected $_ns = ' xmlns:og="http://ogp.me/ns#" xmlns:fb="http://www.facebook.com/2008/fbml"';

/**
 * Map used to correct irregular property names
 **/
	protected $_propertyNames = array(
		'admin'       => 'fb:admins',
		'admins'      => 'fb:admins',
		'app_id'      => 'fb:app_id',
		'appid'       => 'fb:app_id',
		'appId'       => 'fb:app_id',
		'appID'       => 'fb:app_id',
		'url'         => 'og:url',
		'URL'         => 'og:url',
		'type'        => 'og:type',
		'title'       => 'og:title',
		'locale'      => 'og:locale',
		'site_name'   => 'og:site_name',
		'sitename'    => 'og:site_name',
		'siteName'    => 'og:site_name',
		'image'       => 'og:image',
		'img'       => 'og:image',
		'description' => 'og:description',
	);

	protected $_properties = array();

	public function __construct() {
		$this->view =& ClassRegistry::getObject('view');
	}

/**
 * Sets default values
 **/
	public function beforeRender() {
		$this->defaults = $this->_normalize($this->defaults);
		$conf = $this->_normalize(Configure::read($this->configName));
		$viewVar = $this->_normalize($this->view->getVar($this->varName));
		$ogp = array_merge($this->defaults, $conf, $viewVar);

		if ($this->autoGetUrl && empty($ogp['og:url'])) {
			$ogp['og:url'] = $this->url(null, true);
		}

		if ($this->autoGetTitle && empty($ogp['og:title'])) {
			$ogp['og:title'] = $this->_getTitle();
		}

		if ($this->autoGetSiteName && empty($ogp['og:site_name'])) {
			$ogp['og:site_name'] = $this->_getSiteName();
		}

		if ($this->autoGetLocale && empty($ogp['og:locale'])) {
			$ogp['og:locale'] = $this->_getLocale();
		}

		foreach ($ogp as $property => $content) {
			$this->set($property, $content);
		}
	}

/**
 * Sets a meta tag in the view layout's <head />
 **/
	public function set($property, $content = false, $id = false) {
		if ($property) {
			$property = $this->_getPropertyName($property);
			if (empty($this->_properties[$property]) || !in_array($content, $this->_properties[$property])) {
				if ($id === false) {
					if ($property == 'og:image' && isset($this->_properties['og:image'])) {
						$id = count($this->_properties['og:image']);
					} else {
						$id = 0;
					}
				}

				if ($content === false) {
					return $this->delete($property, $id);
				} else {
					$propertyId = $this->_getPropertyId($property, $id);
					$meta = $this->Html->meta(null, null, array(
						'property' => $property,
						'content' => $content,
						'inline' => true,
					));
					$this->view->addScript($propertyId, $meta);
					$this->_properties[$property][$id] = $meta;
				}
			}
		}
		return $content;
	}

/**
 * Deletes a tag associated with property name and the ID.
 **/
	public function delete($property, $id = 0) {
		if ($property) {
			$property = $this->_getPropertyName($property);
			$propertyId = $this->_getPropertyId($property, $id);
			if (isset($this->view->__scripts[$propertyId], $this->_properties[$property][$id])) {
				unset($this->view->__scripts[$propertyId]);
				unset($this->_properties[$property][$id]);
				return true;
			}
		}
		return false;
	}

/**
 * Returns namespace attributes for OGP and Facebook.
 **/
	public function ns() {
		return $this->_ns;
	}

/**
 * Normalizes property names set as keys of an array
 **/
	protected function _normalize($ogp) {
		if (is_array($ogp)) {
			foreach ($ogp as $property => $content) {
				$propertyName = $this->_getPropertyName($property);
				if ($propertyName != $property) {
					unset($ogp[$property]);
					$ogp[$propertyName] = $content;
				}
			}
		} else {
			$ogp = array();
		}
		return $ogp;
	}

/**
 * Returns a proper property name for an OGP tag
 **/
	protected function _getPropertyName($property) {
		if (isset($this->_propertyNames[$property])) {
			$property = $this->_propertyNames[$property];
		}
		return $property;
	}

/**
 * Returns the $title_for_layout for the current view
 **/
	protected function _getTitle() {
		if (!$title = $this->view->getVar('title_for_layout')) {
			$title = Inflector::humanize($this->view->viewPath);
		}
		if ($title) {
			return __($title, true);
		} else {
			return false;
		}
	}

/**
 * Returns the <title /> in the layout
 **/
	protected function _getSiteName() {
		$layoutFileName = $this->view->_getLayoutFileName();
		if ($layoutFileName && file_exists($layoutFileName)) {
			if ($layout = file_get_contents($layoutFileName)) {
				$layout = str_replace(array("\r", "\n"), ' ', $layout);
				$pattern = '#<title.*?>(.+?)</title.*?>#i';
				preg_match($pattern, $layout, $matches);
				$title = $matches[1];

				$pattern = '/<\?(?:php|=)(.*?)\?>/i';
				preg_match_all($pattern, $title, $codes);

				if (is_array($codes[1]) && $codes[1]) {
					$debug = Configure::read('debug');
					Configure::write('debug', 0);
					foreach ($codes[1] as $key => $code) {
						ob_start();
						eval($code);
						$result = ob_get_contents();
						ob_end_clean();
						$title = str_replace($codes[0][$key], $result, $title);
					}
					Configure::write('debug', $debug);
				}
				$title = trim($title);
				if ($title) {
					return $title;
				}
			}
		}
		return false;
	}

/**
 * Returns a Facebook locale code associated with Config.language
 **/
	protected function _getLocale() {
		if (!class_exists('L10n')) {
			App::import('Core', 'l10n');
		}
		$l10n = new L10n;
		$l10n->get();
		$language = Configure::read('Config.language');
		if (!empty($_SESSION['Config']['language'])) {
			$language = $_SESSION['Config']['language'];
		}
		if ($language) {
			$this->locales = array_merge($this->locales, (array)Configure::read($this->configLocaleName));
			if (!empty($this->locales[$language])) {
				return $this->locales[$language];
			}
		}
		return false;
	}

/**
 * Creates a property ID string
 **/
	protected function _getPropertyId($property, $id) {
		return $property . '-' . $id;
	}
}