bearer.php

<?php
/**
 * Tweet Display Back Module for Joomla!
 *
 * @copyright  Copyright (C) 2010-2015 Michael Babker. All rights reserved.
 * @license    http://www.gnu.org/licenses/gpl-2.0.txt GNU General Public License Version 2 or Later
 */

defined('JPATH_PLATFORM') or die;

/**
 * Bearer class for Tweet Display Back
 *
 * @since  3.1
 */
class BDBearer
{
	/**
	 * The name of the cache file to use to store the bearer token
	 *
	 * @var    string
	 * @since  3.1
	 */
	private $cache_file = 'tweetdisplayback_bearer.json';

	/**
	 * The time in seconds to cache the bearer token
	 *
	 * @var    integer
	 * @since  3.1
	 */
	private $cache_time = -1;

	/**
	 * BDHttp connector
	 *
	 * @var    BDHttp
	 * @since  3.1
	 */
	protected $connector = null;

	/**
	 * The bearer token
	 *
	 * @var    string
	 * @since  3.1
	 */
	public $token = null;

	/**
	 * Constructor
	 *
	 * @param   JRegistry  $params     The module parameters
	 * @param   BDHttp     $connector  BDHttp connector
	 *
	 * @since   3.1
	 */
	public function __construct($params, BDHttp $connector)
	{
		// Store the module params
		$this->params = $params;

		// Store the connector
		$this->connector = $connector;

		// Prepare the token
		$this->prepareToken();
	}

	/**
	 * Function to create the bearer authentication value for use in HTTP headers
	 *
	 * @return  string
	 *
	 * @since   3.1
	 */
	protected function prepareBearerAuth()
	{
		$ckey = rawurlencode($this->params->get('consumer_key', ''));
		$csec = rawurlencode($this->params->get('consumer_secret', ''));

		return ($ckey && $csec) ? base64_encode("{$ckey}:{$csec}") : '';
	}

	/**
	 * Function to convert the bearer_cache_time_unit and _qty into epoch seconds
	 *
	 * @return  integer  The time in seconds to cache the bearer token
	 *
	 * @since   3.1
	 */
	protected function cacheTime()
	{
		if ($this->cache_time < 0)
		{
			$this->prepareCacheTime();
		}

		return (int) $this->cache_time;
	}

	/**
	 * Function to retrieve a bearer token from Twitter's API using a consumer key
	 *
	 * @return  void
	 *
	 * @since   3.1
	 * @throws  RuntimeException
	 */
	protected function callConsumer()
	{
		$auth = $this->prepareBearerAuth();

		if ($auth)
		{
			$url      = "https://api.twitter.com/oauth2/token";
			$headers  = array(
				'Authorization' => "Basic {$auth}",
			);

			$data     = "grant_type=client_credentials";
			$response = $this->connector->post($url, $data, $headers);

			if ($response->code == 200)
			{
				$this->token = json_decode($response->body)->access_token;
			}
			else
			{
				throw new RuntimeException('Could not retrieve bearer token (consumer)');
			}

			$this->writeCache();
		}
		else
		{
			throw new RuntimeException('Invalid consumer key/secret in configuration');
		}
	}

	/**
	 * Function to retrieve a bearer token from a remote URL
	 *
	 * @return  void
	 *
	 * @since   3.1
	 * @throws  RuntimeException
	 */
	protected function callRemoteUrl()
	{
		$url = $this->params->get('remote_url', 'http://tdbtoken.gopagoda.com/tokenRequest.php');

		// Call consumer or RemoteURL
		$response = $this->connector->get($url);

		if ($response->code == 200)
		{
			$this->token = str_replace('Bearer ', '', base64_decode($response->body));
		}
		else
		{
			throw new RuntimeException('Could not retrieve bearer token (remote)');
		}

		$this->writeCache();
	}

	/**
	 * Function to convert the bearer_cache_time_unit and _qty into epoch seconds
	 *
	 * @return  void
	 *
	 * @since   3.1
	 */
	protected function prepareCacheTime()
	{
		$cacheTime = (int) $this->params->get('bearer_cache_time_qty', 1);
		$cacheUnit = $this->params->get('bearer_cache_time_unit', '');

		if (!$cacheUnit)
		{
			$cacheUnit = 'day';
			$cacheTime = 1;
		}

		switch ($cacheUnit)
		{
			case 'hour':
				$cacheTime *= 3600;
				break;

			case 'min':
				$cacheTime *= 60;
				break;

			case 'week':
				$cacheTime *= 86400 * 7;
				break;

			case 'noexp':
				$cacheTime = 0;
				break;

			case 'day':
			default:
				$cacheTime *= 86400;
				break;
		}

		$this->cache_time = $cacheTime;
	}

	/**
	 * Function to obtain a bearer token, if none is cached
	 *
	 * @return  boolean  True if a bearer token is available, otherwise false
	 *
	 * @since   3.1
	 */
	protected function prepareToken()
	{
		// If we haven't retrieved the bearer yet, get it if in the site application
		if (($this->token == null) && JFactory::getApplication()->isSite())
		{
			$cacheTime = $this->cacheTime();
			$cacheFile = JPATH_CACHE . DIRECTORY_SEPARATOR . $this->cache_file;

			// Check if we have cached data and use it if unexpired
			if (!file_exists($cacheFile) || ($cacheTime && (time() - @filemtime($cacheFile) > $cacheTime)))
			{
				// call consumer or RemoteURL
				switch ($this->params->get('token_source', 'consumer'))
				{
					case 'remote':
						$this->callRemoteUrl();
						break;

					case 'consumer':
					default:
						$this->callConsumer();
						break;
				}

				// Write the cache
				$this->writeCache();
			}
			else
			{
				// Render from the cached data
				$this->token = $this->readCache();
			}
		}

		return !empty($this->token);
	}

	/**
	 * Function to read the bearer token from cache
	 *
	 * @return  string
	 *
	 * @since   3.1
	 */
	protected function readCache()
	{
		$cacheFile = JPATH_CACHE . '/' . $this->cache_file;
		$ret       = '';

		if (file_exists($cacheFile))
		{
			$ret = file_get_contents($cacheFile);
		}

		return $ret;
	}

	/**
	 * Function to cache the bearer token
	 *
	 * @return  void
	 *
	 * @since   3.1
	 */
	protected function writeCache()
	{
		$cacheFile = JPATH_CACHE . DIRECTORY_SEPARATOR . $this->cache_file;

		// Write the cache
		file_put_contents($cacheFile, $this->token);
	}
}