"""SMTP email backend class."""
import smtplib
import socket
import threading
from django.conf import settings
from django.core.mail.backends.base import BaseEmailBackend
from django.core.mail.utils import DNS_NAME
class EmailBackend(BaseEmailBackend):
"""
A wrapper that manages the SMTP network connection.
"""
def __init__(self, host=None, port=None, username=None, password=None,
use_tls=None, fail_silently=False, **kwargs):
super(EmailBackend, self).__init__(fail_silently=fail_silently)
self.host = host or settings.EMAIL_HOST
self.port = port or settings.EMAIL_PORT
self.username = username or settings.EMAIL_HOST_USER
self.password = password or settings.EMAIL_HOST_PASSWORD
if use_tls is None:
self.use_tls = settings.EMAIL_USE_TLS
else:
self.use_tls = use_tls
self.connection = None
self._lock = threading.RLock()
def open(self):
"""
Ensures we have a connection to the email server. Returns whether or
not a new connection was required (True or False).
"""
if self.connection:
# Nothing to do if the connection is already open.
return False
try:
# If local_hostname is not specified, socket.getfqdn() gets used.
# For performance, we use the cached FQDN for local_hostname.
self.connection = smtplib.SMTP(self.host, self.port,
local_hostname=DNS_NAME.get_fqdn())
if self.use_tls:
self.connection.ehlo()
self.connection.starttls()
self.connection.ehlo()
if self.username and self.password:
self.connection.login(self.username, self.password)
return True
except:
if not self.fail_silently:
raise
def close(self):
"""Closes the connection to the email server."""
try:
try:
self.connection.quit()
except socket.sslerror:
# This happens when calling quit() on a TLS connection
# sometimes.
self.connection.close()
except:
if self.fail_silently:
return
raise
finally:
self.connection = None
def send_messages(self, email_messages):
"""
Sends one or more EmailMessage objects and returns the number of email
messages sent.
"""
if not email_messages:
return
self._lock.acquire()
try:
new_conn_created = self.open()
if not self.connection:
# We failed silently on open().
# Trying to send would be pointless.
return
num_sent = 0
for message in email_messages:
sent = self._send(message)
if sent:
num_sent += 1
if new_conn_created:
self.close()
finally:
self._lock.release()
return num_sent
def _send(self, email_message):
"""A helper method that does the actual sending."""
if not email_message.recipients():
return False
try:
self.connection.sendmail(email_message.from_email,
email_message.recipients(),
email_message.message().as_string())
except:
if not self.fail_silently:
raise
return False
return True
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