1: <?php
  2: 
  3: /*
  4:  * This file is part of SwiftMailer.
  5:  * (c) 2004-2009 Chris Corbyn
  6:  *
  7:  * For the full copyright and license information, please view the LICENSE
  8:  * file that was distributed with this source code.
  9:  */
 10: 
 11: /**
 12:  * Redudantly and rotationally uses several Transports when sending.
 13:  *
 14:  * @package Swift
 15:  * @subpackage Transport
 16:  * @author Chris Corbyn
 17:  */
 18: class Swift_Transport_LoadBalancedTransport implements Swift_Transport
 19: {
 20:     /** Transports which are deemed useless */
 21:     private $_deadTransports = array();
 22: 
 23:     /**
 24:      * The Transports which are used in rotation.
 25:      *
 26:      * @var array Swift_Transport
 27:      * @access protected
 28:      */
 29:     protected $_transports = array();
 30: 
 31:     /**
 32:      * Creates a new LoadBalancedTransport.
 33:      */
 34:     public function __construct()
 35:     {
 36:     }
 37: 
 38:     /**
 39:      * Set $transports to delegate to.
 40:      *
 41:      * @param array $transports Swift_Transport
 42:      */
 43:     public function setTransports(array $transports)
 44:     {
 45:         $this->_transports = $transports;
 46:         $this->_deadTransports = array();
 47:     }
 48: 
 49:     /**
 50:      * Get $transports to delegate to.
 51:      *
 52:      * @return array Swift_Transport
 53:      */
 54:     public function getTransports()
 55:     {
 56:         return array_merge($this->_transports, $this->_deadTransports);
 57:     }
 58: 
 59:     /**
 60:      * Test if this Transport mechanism has started.
 61:      *
 62:      * @return boolean
 63:      */
 64:     public function isStarted()
 65:     {
 66:         return count($this->_transports) > 0;
 67:     }
 68: 
 69:     /**
 70:      * Start this Transport mechanism.
 71:      */
 72:     public function start()
 73:     {
 74:         $this->_transports = array_merge($this->_transports, $this->_deadTransports);
 75:     }
 76: 
 77:     /**
 78:      * Stop this Transport mechanism.
 79:      */
 80:     public function stop()
 81:     {
 82:         foreach ($this->_transports as $transport) {
 83:             $transport->stop();
 84:         }
 85:     }
 86: 
 87:     /**
 88:      * Send the given Message.
 89:      *
 90:      * Recipient/sender data will be retrieved from the Message API.
 91:      * The return value is the number of recipients who were accepted for delivery.
 92:      *
 93:      * @param Swift_Mime_Message $message
 94:      * @param string[] &$failedRecipients to collect failures by-reference
 95:      * @return int
 96:      */
 97:     public function send(Swift_Mime_Message $message, &$failedRecipients = null)
 98:     {
 99:         $maxTransports = count($this->_transports);
100:         $sent = 0;
101: 
102:         for ($i = 0; $i < $maxTransports
103:             && $transport = $this->_getNextTransport(); ++$i)
104:         {
105:             try {
106:                 if (!$transport->isStarted()) {
107:                     $transport->start();
108:                 }
109:                 if ($sent = $transport->send($message, $failedRecipients)) {
110:                     break;
111:                 }
112:             } catch (Swift_TransportException $e) {
113:                 $this->_killCurrentTransport();
114:             }
115:         }
116: 
117:         if (count($this->_transports) == 0) {
118:             throw new Swift_TransportException(
119:                 'All Transports in LoadBalancedTransport failed, or no Transports available'
120:                 );
121:         }
122: 
123:         return $sent;
124:     }
125: 
126:     /**
127:      * Register a plugin.
128:      *
129:      * @param Swift_Events_EventListener $plugin
130:      */
131:     public function registerPlugin(Swift_Events_EventListener $plugin)
132:     {
133:         foreach ($this->_transports as $transport) {
134:             $transport->registerPlugin($plugin);
135:         }
136:     }
137: 
138:     // -- Protected methods
139: 
140:     /**
141:      * Rotates the transport list around and returns the first instance.
142:      *
143:      * @return Swift_Transport
144:      * @access protected
145:      */
146:     protected function _getNextTransport()
147:     {
148:         if ($next = array_shift($this->_transports)) {
149:             $this->_transports[] = $next;
150:         }
151: 
152:         return $next;
153:     }
154: 
155:     /**
156:      * Tag the currently used (top of stack) transport as dead/useless.
157:      *
158:      * @access protected
159:      */
160:     protected function _killCurrentTransport()
161:     {
162:         if ($transport = array_pop($this->_transports)) {
163:             try {
164:                 $transport->stop();
165:             } catch (Exception $e) {
166:             }
167:             $this->_deadTransports[] = $transport;
168:         }
169:     }
170: }
171: