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POAm I Using A Factory To Promote Polymorphism?
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copied!<p>My first question is basically asking for a code-review. Does the code I'm about to provide use a Factory to promote Polymorphism? Its written in PHP. Here are the basic requirements:</p> <ul> <li>Pass a long url to a library and return a shortened url. Along with the long url, pass user properties to attempt to locate the users specific shortener service and API key.</li> <li>Allow users to set API keys for specific URL shorteners. My code assumes this is already set in the database and Bitly is the only service supported.</li> <li>If a user doesn't have an API key and service set, use the default API key and service. Again, my code assumes the default is set to Bitly in the database.</li> <li>If the url shortener service fails, log the failure, but don't throw an exception. The library should silently fail. Instead of using the short url, we'll use the long url.</li> </ul> <p>Here is an example of calling the code:</p> <pre><code><?php $long_url = 'http://www.news.com/story/1'; $account_id = 1; $use_this_url = $long_url; $meta = array( 'account_id' => $account_id, // OPTIONS // 'service_id' => $service_id, // 'account_id' => $account_id, ); $shortener = new Shortener_Factory($long_url, $meta); if ($shortener->shorten_long_url() AND $shortener->save_short_url()) { $use_this_url = $shortener->short_url; } echo $use_this_url; </code></pre> <p>Here are the classes:</p> <pre><code><?php interface ShortenerServiceInterface { public function save_short_url(); public function shorten_long_url(); } abstract class ShortenerServiceAbstract implements ShortenerServiceInterface { // Url to be shortened public $long_url = ''; // Long url unique id public $url_id = 0; // Service unique id public $shorturlservice_id = 0; // Service account unique id public $shorturlserviceaccount_id = 0; // Short url service unique API login public $api_login = ''; // Short url service unique API key public $api_key = ''; // Short url service unique hash which maps to original url value public $hash = ''; // Shortened url string public $short_url = ''; // Attempt to call shortner service three times before failing public $attempts = 3; // Shorten long url with specific service API/logic public function shorten_long_url() { // Can't save a short url when one doesn't exist if (!$this->long_url OR !$this->api_login OR !$this->api_key) { log('error', 'ShortenerServiceAbstract::shorten_long_url - no long url to shorten - '.var_export($this, TRUE)); return FALSE; } } // Save short url and related meta-data to shorturls table public function save_short_url() { // Can't save a short url when one doesn't exist if (!$this->url_id OR !$this->hash OR !$this->shorturlservice_id OR !$this->shorturlserviceaccount_id) { log('error', 'ShortenerServiceAbstract::save_short_url - no short url to save - '.var_export($this, TRUE)); return FALSE; } // Insert a new short url, or update an existing record $saved = Shorturl_Model::insert_on_dup_key_update($this->url_id, $this->hash, $this->shorturlservice_id, $this->shorturlserviceaccount_id); if (!$saved) { log('error', 'ShortenerServiceAbstract::save_short_url - short url record can not be saved - '.var_export($this, TRUE)); return FALSE; } else { return TRUE; } } } // Bitly, a simple url shortener // @link http://code.google.com/p/bitly-api/wiki/ApiDocumentation class ShortenerServiceBitly extends ShortenerServiceAbstract { public function shorten_long_url() { // Make sure we have required members set parent::shorten_long_url(); $urlencoded = urlencode($this->long_url); $bitlyurl = 'http://api.bit.ly/shorten?version=2.0.1&longUrl='.$urlencoded.'&login='.$this->api_login.'&apiKey='.$this->api_key.'&history=1'; $attempts = 1; while ($attempts <= 3) { $json_result = file_get_contents($bitlyurl); if ($json_result) { // Return an assoc array $json_decode = json_decode($json_result, TRUE); if (is_array($json_decode) AND isset($json_decode['errorCode']) AND $json_decode['errorCode'] == 0) { // Don't compare sent URL with returned URL // Bitly removes invalid poritions of URLs // The camparison might fail even though the URLs are the "same" $shortened = current($json_decode['results']); break; } else { log('error', 'ShortenerServiceBitly::shorten_long_url - bit.ly json decoded - '.var_export($json_decode, TRUE)); } } else { log('error', 'ShortenerServiceBitly::shorten_long_url - bit.ly http response - '.var_export($json_result, TRUE)); } $attempts++; } if (isset($shortened)) { $this->short_url = $shortened['shortUrl']; $this->hash = $shortened['userHash']; return TRUE; } else { return FALSE; } } } // Shortener Factory class Shortener_Factory { // Shortener service account parameter object // @param object shortener account properties private $_account; // Shortener service object created by factory //@param object shorterner service functions private $_service; // Url to be shortened private $_long_url; // Set url members, service parameter object and finally the service itself public function __construct($long_url, $meta=array()) { $this->_long_url = $long_url; $this->_set_account($meta); $this->_set_service(); } // Set shortener service account parameter object // @param $meta array determine parameters for the current service object private function _set_account($meta=array()) { $s = FALSE; // Get shorturl service account if (isset($meta['account_id'])) { $s = Shorturlserviceaccount_Model::get_by_account_id($meta['account_id']); } elseif (isset($meta['service_id'])) { $s = Shorturlserviceaccount_Model::get_by_service_id($meta['service_id']); } // Account not found, lets use default if (!$s) { $s = Shorturlserviceaccount_Model::get_default(); } // Must have a service to use if ($s === FALSE) { log('error', 'Shortener_Core::_set_account - _account not found - '.var_export($this, TRUE)); return FALSE; } else { $this->_account = $s; } } // Use shortener service account parameter object to set shortener service object private function _set_service() { switch ($this->_account->name) { case 'bitly': $this->_service = new ShortenerServiceBitly; break; default: log('error', 'Shortener_Core::_set_service - _account not set - '.var_export($this, TRUE)); return FALSE; } $this->_service->long_url = $this->_long_url; $this->_service->shorturlserviceaccount_id = $this->_account->id; $this->_service->shorturlservice_id = $this->_account->shorturlservice_id; $this->_service->api_login = $this->_account->api_login; $this->_service->api_key = $this->_account->api_key; } // Public API for shortener service object methods public function __call($name, $arguments) { if (!$this->_service) { log('error', 'Shortener_Core::__call - _service not set - '.var_export($this, TRUE)); return FALSE; } return $this->_service->$name(); } // Public API for shortener service object members public function __get($name) { return ($this->_service->$name) ? $this->_service->$name : NULL; } } </code></pre>

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