"yii\swiftmailer\Mailer" transport setup has been advanced to support constructor arguments and plugins.

extensions/swiftmailer/Mailer.php

@@ -37,6 +37,23 @@ use yii\mail\BaseMailer;
  * You may also skip the configuration of the [[transport]] property. In that case, the default
  * PHP `mail()` function will be used to send emails.
  *
+ * You specify the transport constructor arguments using 'constructArgs' key in the config.
+ * You can also specify the list of plugins, which should be registered to the transport using
+ * 'plugins' key. For example:
+ *
+ * ~~~
+ * 'transport' => [
+ *     'class' => 'Swift_SmtpTransport',
+ *     'constructArgs' => ['localhost', 25]
+ *     'plugins' => [
+ *         [
+ *             'class' => 'Swift_Plugins_ThrottlerPlugin',
+ *             'constructArgs' => [20],
+ *         ],
+ *     ],
+ * ],
+ * ~~~
+ *
  * To send an email, you may use the following code:
  *
  * ~~~
@@ -131,28 +148,69 @@ class Mailer extends BaseMailer
 	 */
 	protected function createTransport(array $config)
 	{
+		if (!isset($config['class'])) {
+			$config['class'] = 'Swift_MailTransport';
+		}
+		if (isset($config['plugins'])) {
+			$plugins = $config['plugins'];
+			unset($config['plugins']);
+		}
+		/** @var \Swift_MailTransport $transport */
+		$transport = $this->createSwiftObject($config);
+		if (isset($plugins)) {
+			foreach ($plugins as $plugin) {
+				if (is_array($plugin) && isset($plugin['class'])) {
+					$plugin = $this->createSwiftObject($plugin);
+				}
+				$transport->registerPlugin($plugin);
+			}
+		}
+		return $transport;
+	}
+
+	/**
+	 * Creates Swift library object, from given array configuration.
+	 * @param array $config object configuration
+	 * @return Object created object
+	 * @throws \yii\base\InvalidConfigException on invalid configuration.
+	 */
+	protected function createSwiftObject(array $config)
+	{
 		if (isset($config['class'])) {
 			$className = $config['class'];
 			unset($config['class']);
 		} else {
-			$className = 'Swift_MailTransport';
+			throw new InvalidConfigException('Object configuration must be an array containing a "class" element.');
+		}
+		if (isset($config['constructArgs'])) {
+			$args = [];
+			foreach ($config['constructArgs'] as $arg) {
+				if (is_array($arg) && isset($arg['class'])) {
+					$args[] = $this->createSwiftObject($arg);
+				} else {
+					$args[] = $arg;
+				}
+			}
+			unset($config['constructArgs']);
+			array_unshift($args, ['class' => $className]);
+			$object = call_user_func_array(['Yii', 'createObject'], $args);
+		} else {
+			$object = new $className;
 		}
-		/** @var \Swift_MailTransport $transport */
-		$transport = $className::newInstance();
 		if (!empty($config)) {
 			foreach ($config as $name => $value) {
-				if (property_exists($transport, $name)) {
-					$transport->$name = $value;
+				if (property_exists($object, $name)) {
+					$object->$name = $value;
 				} else {
 					$setter = 'set' . $name;
-					if (method_exists($transport, $setter) || method_exists($transport, '__call')) {
-						$transport->$setter($value);
+					if (method_exists($object, $setter) || method_exists($object, '__call')) {
+						$object->$setter($value);
 					} else {
-						throw new InvalidConfigException('Setting unknown property: ' . get_class($transport) . '::' . $name);
+						throw new InvalidConfigException('Setting unknown property: ' . $className . '::' . $name);
 					}
 				}
 			}
 		}
-		return $transport;
+		return $object;
 	}
 }

tests/unit/extensions/swiftmailer/MailerTest.php

@@ -63,6 +63,56 @@ class MailerTest extends VendorTestCase
 		$this->assertEquals($transportConfig['host'], $transport->getHost(), 'Invalid transport host!');
 	}
 
+	/**
+	 * @depends testConfigureTransport
+	 */
+	public function testConfigureTransportConstruct()
+	{
+		$mailer = new Mailer();
+
+		$host = 'some.test.host';
+		$port = 999;
+		$transportConfig = [
+			'class' => 'Swift_SmtpTransport',
+			'constructArgs' => [
+				$host,
+				$port,
+			],
+		];
+		$mailer->setTransport($transportConfig);
+		$transport = $mailer->getTransport();
+		$this->assertTrue(is_object($transport), 'Unable to setup transport via config!');
+		$this->assertEquals($host, $transport->getHost(), 'Invalid transport host!');
+		$this->assertEquals($port, $transport->getPort(), 'Invalid transport host!');
+	}
+
+	/**
+	 * @depends testConfigureTransportConstruct
+	 */
+	public function testConfigureTransportWithPlugins()
+	{
+		$mailer = new Mailer();
+
+		$pluginClass = 'Swift_Plugins_ThrottlerPlugin';
+		$rate = 10;
+
+		$transportConfig = [
+			'class' => 'Swift_SmtpTransport',
+			'plugins' => [
+				[
+					'class' => $pluginClass,
+					'constructArgs' => [
+						$rate,
+					],
+				],
+			],
+		];
+		$mailer->setTransport($transportConfig);
+		$transport = $mailer->getTransport();
+		$this->assertTrue(is_object($transport), 'Unable to setup transport via config!');
+		$this->assertContains(':' . $pluginClass . ':', print_r($transport, true), 'Plugin not added');
+	}
+
 	public function testGetSwiftMailer()
 	{
 		$mailer = new Mailer();