feat: added bcc only emails to smtp

.env.dev

@@ -1,3 +1,4 @@
+SMTP_DEFAULT_RECIPIENT=
 MAILGUN_API_KEY=
 MAILGUN_DOMAIN=
 SENDGRID_API_KEY=

.github/workflows/test.yml

@@ -14,6 +14,7 @@ jobs:
     - run: git checkout HEAD^2
     - name: Run Tests 
       env:
+        SMTP_DEFAULT_RECIPIENT: ${{ secrets.SMTP_DEFAULT_RECIPIENT }}
         MAILGUN_API_KEY: ${{ secrets.MAILGUN_API_KEY }}
         MAILGUN_DOMAIN: ${{ secrets.MAILGUN_DOMAIN }}
         SENDGRID_API_KEY: ${{ secrets.SENDGRID_API_KEY }}

docker-compose.yml

@@ -7,6 +7,7 @@ services:
       - ./tests:/usr/local/src/tests
       - ./phpunit.xml:/usr/local/src/phpunit.xml
     environment:
+      - SMTP_DEFAULT_RECIPIENT
       - MAILGUN_API_KEY
       - MAILGUN_DOMAIN
       - SENDGRID_API_KEY

src/Utopia/Messaging/Adapter/Email/SMTP.php

@@ -19,6 +19,7 @@ class SMTP extends EmailAdapter
      * @param string $smtpSecure SMTP Secure prefix. Can be '', 'ssl' or 'tls'
      * @param bool $smtpAutoTLS Enable/disable SMTP AutoTLS feature. Defaults to false.
      * @param string $xMailer The value to use for the X-Mailer header.
+     * @param string $defaultRecipient The default recipient to use for the email.
      */
     public function __construct(
         private string $host,
@@ -27,7 +28,8 @@ public function __construct(
         private string $password = '',
         private string $smtpSecure = '',
         private bool $smtpAutoTLS = false,
-        private string $xMailer = ''
+        private string $xMailer = '',
+        private string $defaultRecipient = ''
     ) {
         if (!\in_array($this->smtpSecure, ['', 'ssl', 'tls'])) {
             throw new \InvalidArgumentException('Invalid SMTP secure prefix. Must be "", "ssl" or "tls"');
@@ -72,6 +74,14 @@ protected function process(EmailMessage $message): array
         $mail->AltBody = \strip_tags($mail->AltBody);
         $mail->AltBody = \trim($mail->AltBody);
 
+        if (empty($message->getTo())) {
+            if (empty($message->getBCC()) || empty($this->defaultRecipient)) {
+                throw new \Exception('Email requires either "to" recipients or both BCC and a default recipient configurations');
+            }
+
+            $mail->addAddress($this->defaultRecipient);
+        }
+
         foreach ($message->getTo() as $to) {
             $mail->addAddress($to);
         }

tests/Messaging/Adapter/Email/SMTPTest.php

@@ -78,4 +78,44 @@ public function testSendEmailWithAttachment(): void
         $this->assertEquals($subject, $lastEmail['subject']);
         $this->assertEquals($content, \trim($lastEmail['text']));
     }
+
+    public function testSendEmailOnlyBCC(): void
+    {
+        $defaultRecipient = \getenv('SMTP_DEFAULT_RECIPIENT') ?? 'placeholder@localhost.test';
+        $sender = new SMTP(
+            host: 'maildev',
+            port: 1025,
+            defaultRecipient: $defaultRecipient,
+        );
+
+        $subject = 'Test Subject';
+        $content = 'Test Content';
+        $fromName = 'Test Sender';
+        $fromEmail = 'sender@localhost.test';
+        $bcc = [
+            [
+                'email' => 'tester@localhost.test',
+                'name' => 'Test Recipient',
+            ],
+        ];
+
+        $message = new Email(
+            to: [],
+            subject: $subject,
+            content: $content,
+            fromName: $fromName,
+            fromEmail: $fromEmail,
+            bcc: $bcc,
+        );
+
+        $response = $sender->send($message);
+
+        $lastEmail = $this->getLastEmail();
+
+        $this->assertResponse($response);
+        $this->assertEquals($defaultRecipient, $lastEmail['to'][0]['address']);
+        $this->assertEquals($fromEmail, $lastEmail['from'][0]['address']);
+        $this->assertEquals($subject, $lastEmail['subject']);
+        $this->assertEquals($content, \trim($lastEmail['text']));
+    }
 }