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"""SMTP email backend class."""
import smtplib
import socket
import ssl
import threading
from django.conf import settings
from django.core.mail.backends.base import BaseEmailBackend
from django.core.mail.message import sanitize_address
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, use_ssl=None, timeout=None,
ssl_keyfile=None, ssl_certfile=None,
**kwargs):
super().__init__(fail_silently=fail_silently)
self.host = host or settings.EMAIL_HOST
self.port = port or settings.EMAIL_PORT
self.username = settings.EMAIL_HOST_USER if username is None else username
self.password = settings.EMAIL_HOST_PASSWORD if password is None else password
self.use_tls = settings.EMAIL_USE_TLS if use_tls is None else use_tls
self.use_ssl = settings.EMAIL_USE_SSL if use_ssl is None else use_ssl
self.timeout = settings.EMAIL_TIMEOUT if timeout is None else timeout
self.ssl_keyfile = settings.EMAIL_SSL_KEYFILE if ssl_keyfile is None else ssl_keyfile
self.ssl_certfile = settings.EMAIL_SSL_CERTFILE if ssl_certfile is None else ssl_certfile
if self.use_ssl and self.use_tls:
raise ValueError(
"EMAIL_USE_TLS/EMAIL_USE_SSL are mutually exclusive, so only set "
"one of those settings to True.")
self.connection = None
self._lock = threading.RLock()
@property
def connection_class(self):
return smtplib.SMTP_SSL if self.use_ssl else smtplib.SMTP
def open(self):
"""
Ensure an open connection to the email server. Return whether or not a
new connection was required (True or False) or None if an exception
passed silently.
"""
if self.connection:
# Nothing to do if the connection is already open.
return False
# If local_hostname is not specified, socket.getfqdn() gets used.
# For performance, we use the cached FQDN for local_hostname.
connection_params = {'local_hostname': DNS_NAME.get_fqdn()}
if self.timeout is not None:
connection_params['timeout'] = self.timeout
if self.use_ssl:
connection_params.update({
'keyfile': self.ssl_keyfile,
'certfile': self.ssl_certfile,
})
try:
self.connection = self.connection_class(self.host, self.port, **connection_params)
# TLS/SSL are mutually exclusive, so only attempt TLS over
# non-secure connections.
if not self.use_ssl and self.use_tls:
self.connection.starttls(keyfile=self.ssl_keyfile, certfile=self.ssl_certfile)
if self.username and self.password:
self.connection.login(self.username, self.password)
return True
except (smtplib.SMTPException, socket.error):
if not self.fail_silently:
raise
def close(self):
"""Close the connection to the email server."""
if self.connection is None:
return
try:
try:
self.connection.quit()
except (ssl.SSLError, smtplib.SMTPServerDisconnected):
# This happens when calling quit() on a TLS connection
# sometimes, or when the connection was already disconnected
# by the server.
self.connection.close()
except smtplib.SMTPException:
if self.fail_silently:
return
raise
finally:
self.connection = None
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
with self._lock:
new_conn_created = self.open()
if not self.connection or new_conn_created is None:
# 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()
return num_sent
def _send(self, email_message):
"""A helper method that does the actual sending."""
if not email_message.recipients():
return False
encoding = email_message.encoding or settings.DEFAULT_CHARSET
from_email = sanitize_address(email_message.from_email, encoding)
recipients = [sanitize_address(addr, encoding) for addr in email_message.recipients()]
message = email_message.message()
try:
self.connection.sendmail(from_email, recipients, message.as_bytes(linesep='\r\n'))
except smtplib.SMTPException:
if not self.fail_silently:
raise
return False
return True