Flask-Mailman backend to send emails via AWS SES

flask_mailman_ses.py

"""Flask-Mailman backend to send emails via AWS SES."""
import boto3
from botocore.exceptions import ClientError
from flask_mailman.backends.base import BaseEmailBackend


class EmailBackend(BaseEmailBackend):
    """Implements sending email via SES through boto3.

    Usage (in settings):

    MAIL_BACKEND = 'flask_mailman_ses.EmailBackend'
    """

    def __init__(self, *args, **kwargs):
        super().__init__(*args, **kwargs)
        self.client = boto3.client('ses')

    def send_messages(self, email_messages):
        """Send one or more EmailMessage objects and return the number of email messages sent."""
        if not email_messages:
            return 0

        num_sent = 0
        for message in email_messages:
            num_sent += self._send(message)
        return num_sent

    def _send(self, message):
        """Sends a single instance of flask_mailman.EmailMessage."""
        try:
            email_message = message.message()
            response = self.client.send_raw_email(
                Source=email_message['From'],
                Destinations=message.recipients(),
                RawMessage={'Data': email_message.as_string()},
            )
            return 1 if response.get('MessageId') else 0
        except ClientError:
            if self.fail_silently:
                return 0
            raise