<?php
/*
* This file is part of SwiftMailer.
* (c) 2004-2009 Chris Corbyn
*
* For the full copyright and license information, please view the LICENSE
* file that was distributed with this source code.
*/
/**
* Redundantly and rotationally uses several Transports when sending.
*
* @author Chris Corbyn
*/
class Swift_Transport_LoadBalancedTransport implements Swift_Transport
{
/**
* Transports which are deemed useless.
*
* @var Swift_Transport[]
*/
private $deadTransports = array();
/**
* The Transports which are used in rotation.
*
* @var Swift_Transport[]
*/
protected $transports = array();
/**
* The Transport used in the last successful send operation.
*
* @var Swift_Transport
*/
protected $lastUsedTransport = null;
// needed as __construct is called from elsewhere explicitly
public function __construct()
{
}
/**
* Set $transports to delegate to.
*
* @param Swift_Transport[] $transports
*/
public function setTransports(array $transports)
{
$this->transports = $transports;
$this->deadTransports = array();
}
/**
* Get $transports to delegate to.
*
* @return Swift_Transport[]
*/
public function getTransports()
{
return array_merge($this->transports, $this->deadTransports);
}
/**
* Get the Transport used in the last successful send operation.
*
* @return Swift_Transport
*/
public function getLastUsedTransport()
{
return $this->lastUsedTransport;
}
/**
* Test if this Transport mechanism has started.
*
* @return bool
*/
public function isStarted()
{
return count($this->transports) > 0;
}
/**
* Start this Transport mechanism.
*/
public function start()
{
$this->transports = array_merge($this->transports, $this->deadTransports);
}
/**
* Stop this Transport mechanism.
*/
public function stop()
{
foreach ($this->transports as $transport) {
$transport->stop();
}
}
/**
* {@inheritdoc}
*/
public function ping()
{
foreach ($this->transports as $transport) {
if (!$transport->ping()) {
$this->killCurrentTransport();
}
}
return count($this->transports) > 0;
}
/**
* Send the given Message.
*
* Recipient/sender data will be retrieved from the Message API.
* The return value is the number of recipients who were accepted for delivery.
*
* @param Swift_Mime_SimpleMessage $message
* @param string[] $failedRecipients An array of failures by-reference
*
* @return int
*/
public function send(Swift_Mime_SimpleMessage $message, &$failedRecipients = null)
{
$maxTransports = count($this->transports);
$sent = 0;
$this->lastUsedTransport = null;
for ($i = 0; $i < $maxTransports
&& $transport = $this->getNextTransport(); ++$i) {
try {
if (!$transport->isStarted()) {
$transport->start();
}
if ($sent = $transport->send($message, $failedRecipients)) {
$this->lastUsedTransport = $transport;
break;
}
} catch (Swift_TransportException $e) {
$this->killCurrentTransport();
}
}
if (count($this->transports) == 0) {
throw new Swift_TransportException(
'All Transports in LoadBalancedTransport failed, or no Transports available'
);
}
return $sent;
}
/**
* Register a plugin.
*
* @param Swift_Events_EventListener $plugin
*/
public function registerPlugin(Swift_Events_EventListener $plugin)
{
foreach ($this->transports as $transport) {
$transport->registerPlugin($plugin);
}
}
/**
* Rotates the transport list around and returns the first instance.
*
* @return Swift_Transport
*/
protected function getNextTransport()
{
if ($next = array_shift($this->transports)) {
$this->transports[] = $next;
}
return $next;
}
/**
* Tag the currently used (top of stack) transport as dead/useless.
*/
protected function killCurrentTransport()
{
if ($transport = array_pop($this->transports)) {
try {
$transport->stop();
} catch (Exception $e) {
}
$this->deadTransports[] = $transport;
}
}
}