Merge pull request #21 from geekdevs/feature/headers

Added support for custom headers

src/Services/SendGridTransport.php

@@ -68,6 +68,15 @@ class SendGridTransport implements Swift_Transport
      */
     private $eventDispatcher;
 
+    /**
+     * Some header keys are reserved. You may not include any of the following reserved keys
+     * (From SendGrid docs)
+     */
+    const RESERVED_KEYWORDS = [
+        'x-sg-id', 'x-sg-eid', 'received', 'dkim-signature', 'Content-Type', 'Content-Transfer-Encoding',
+        'To', 'From', 'Subject', 'Reply-To', 'CC', 'BCC'
+    ];
+
     public function __construct(Swift_Events_EventDispatcher $eventDispatcher, $sendGridApiKey, $sendGridCategories)
     {
         $this->eventDispatcher = $eventDispatcher;
@@ -220,6 +229,16 @@ public function send(Swift_Mime_SimpleMessage $message, &$failedRecipients = nul
             }
         }
 
+        // add headers
+        if ($headers = $message->getHeaders()->getAll()) {
+            foreach ($headers as $header) {
+                $headerName = $header->getFieldName();
+                if (!in_array($headerName, self::RESERVED_KEYWORDS)) {
+                    $mail->addHeader($headerName, $header->getFieldBody());
+                }
+            }
+        }
+
         $sendGrid = new SendGrid($this->sendGridApiKey, $this->httpClientOptions);
 
         $response = $sendGrid->client->mail()->send()->post($mail);