feat: #30 add email sender protocol

Author: payamnj

django_email_learning/ports/__init__.py

@@ -0,0 +1,7 @@
+from typing import Protocol
+from django.core.mail import EmailMultiAlternatives
+
+
+class EmailSenderProtocol(Protocol):
+    def send_email(self, email: EmailMultiAlternatives) -> None:
+        ...

django_email_learning/ports/email_sender_protocol.py

@@ -0,0 +1,36 @@
+import logging
+from django_email_learning.ports.email_sender_protocol import EmailSenderProtocol
+from django.core.mail import EmailMultiAlternatives
+from django.core.mail.message import BadHeaderError
+from smtplib import SMTPException
+
+logger = logging.getLogger(__name__)
+
+
+class DjangoEmailSender(EmailSenderProtocol):
+    def _mask_email(self, email_address: str) -> str:
+        """Mask email address for logging privacy."""
+        try:
+            username, domain = email_address.split("@")
+            masked_username = username[0] + "***"
+            return f"{masked_username}@{domain}"
+        except ValueError:
+            return "***@***"
+
+    def _mask_recipients(self, recipients: list[str]) -> str:
+        """Mask all recipient email addresses for logging."""
+        if not recipients:
+            return "no recipients"
+        masked = [self._mask_email(recipient) for recipient in recipients]
+        return ", ".join(masked)
+
+    def send_email(self, email: EmailMultiAlternatives) -> None:
+        try:
+            masked_recipients = self._mask_recipients(email.to)
+            logger.info(f"Sending email to {masked_recipients}")
+            email.send()
+            logger.info(f"Email sent successfully to {masked_recipients}")
+        except (SMTPException, BadHeaderError) as e:
+            masked_recipients = self._mask_recipients(email.to)
+            logger.error(f"Failed to send email to {masked_recipients}: {str(e)}")
+            raise