add default headers setup

src/Mailer.php

@@ -29,17 +29,39 @@ class Mailer extends CApplicationComponent
      */
     public $dsn;
 
+    /**
+     * @var array<string, string|string[]> the default headers to be applied for each sending email.
+     * For example:
+     *
+     * ```
+     * [
+     *     'From' => 'My App<[email protected]>',
+     *     'Bcc' => '[email protected]',
+     *     'X-Custom-Header' => 'foobar',
+     * ]
+     * ```
+     */
+    public $defaultHeaders = [];
+
     /**
      * @var \Symfony\Component\Mailer\Mailer Swift mailer instance.
      */
     private $_symfonyMailer;
+
     /**
      * @var \Symfony\Component\Mailer\Transport\TransportInterface|\Closure|string|null transport instance or its class name or factory PHP callback.
      */
     private $_transport;
 
     public function send(RawMessage $message, ?Envelope $envelope = null): void
     {
+        foreach ($this->defaultHeaders as $name => $value) {
+            if (in_array(strtolower($name), ['from', 'to', 'cc', 'bcc', 'reply-to'])) {
+                $value = (array) $value;
+            }
+            $message->getHeaders()->addHeader($name, $value);
+        }
+
         $this->getSymfonyMailer()->send($message, $envelope);
     }
 

tests/MailerTest.php

@@ -5,6 +5,7 @@
 use Symfony\Component\Mailer\Mailer as SymfonyMailer;
 use Symfony\Component\Mailer\Transport\Smtp\SmtpTransport;
 use Symfony\Component\Mailer\Transport\NullTransport;
+use Symfony\Component\Mime\Email;
 use Yii;
 use yii1tech\mailer\Mailer;
 use yii1tech\mailer\transport\ArrayTransport;
@@ -73,4 +74,32 @@ public function testSetupSymfonyMailer(): void
         $mailer->setSymfonyMailer($symfonyMailer);
         $this->assertSame($symfonyMailer, $mailer->getSymfonyMailer());
     }
+
+    public function testDefaultHeaders(): void
+    {
+        $transport = new ArrayTransport();
+
+        /** @var Mailer $mailer */
+        $mailer = Yii::createComponent([
+            'class' => Mailer::class,
+            'transport' => $transport,
+            'defaultHeaders' => [
+                'From' => 'My App<[email protected]>',
+                'Bcc' => '[email protected]',
+            ],
+        ]);
+
+        $email = new Email();
+        $email->addTo('[email protected]');
+        $email->subject('Test subject');
+        $email->text('Test body');
+
+        $mailer->send($email);
+
+        $sentMessage = $transport->getLastSentMessage();
+
+        $this->assertSame('[email protected]', $sentMessage->getFrom()[0]->getAddress());
+        $this->assertSame('My App', $sentMessage->getFrom()[0]->getName());
+        $this->assertSame('[email protected]', $sentMessage->getBcc()[0]->getAddress());
+    }
 }