275 lines
8.0 KiB
Python
275 lines
8.0 KiB
Python
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#!/usr/bin/env python
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# -*- coding: utf-8 -*-
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import sys
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import os
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import logging
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import email
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import email.mime.multipart
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import email.mime.application
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import email.encoders
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import smtplib
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import copy
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from io import BytesIO
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try:
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from configparser import SafeConfigParser # Python 3
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except ImportError:
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from ConfigParser import SafeConfigParser # Python 2
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import gpgme
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# Boiler plate to avoid dependency on six
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# BBB: Python 2.7 support
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PY3K = sys.version_info > (3, 0)
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def message_from_binary(message):
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if PY3K:
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return email.message_from_bytes(message)
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else:
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return email.message_from_string(message)
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def as_binary_string(email):
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if PY3K:
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return email.as_bytes()
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else:
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return email.as_string()
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def encode_string(string):
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if isinstance(string, bytes):
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return string
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else:
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return string.encode('utf-8')
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__title__ = 'Zeyple'
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__version__ = '1.2.0'
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__author__ = 'Cédric Félizard'
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__license__ = 'AGPLv3+'
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__copyright__ = 'Copyright 2012-2016 Cédric Félizard'
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class Zeyple:
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"""Zeyple Encrypts Your Precious Log Emails"""
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def __init__(self, config_fname='zeyple.conf'):
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self.config = self.load_configuration(config_fname)
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log_file = self.config.get('zeyple', 'log_file')
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logging.basicConfig(
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filename=log_file, level=logging.DEBUG,
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format='%(asctime)s %(process)s %(levelname)s %(message)s'
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)
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logging.info("Zeyple ready to encrypt outgoing emails")
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def load_configuration(self, filename):
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"""Reads and parses the config file"""
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config = SafeConfigParser()
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config.read([
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os.path.join('/etc/', filename),
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filename,
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])
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if not config.sections():
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raise IOError('Cannot open config file.')
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return config
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@property
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def gpg(self):
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protocol = gpgme.PROTOCOL_OpenPGP
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if self.config.has_option('gpg', 'executable'):
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executable = self.config.get('gpg', 'executable')
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else:
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executable = None # Default value
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home_dir = self.config.get('gpg', 'home')
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ctx = gpgme.Context()
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ctx.set_engine_info(protocol, executable, home_dir)
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ctx.armor = True
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return ctx
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def process_message(self, message_data, recipients):
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"""Encrypts the message with recipient keys"""
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message_data = encode_string(message_data)
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in_message = message_from_binary(message_data)
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logging.info(
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"Processing outgoing message %s", in_message['Message-id'])
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if not recipients:
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logging.warn("Cannot find any recipients, ignoring")
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sent_messages = []
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for recipient in recipients:
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logging.info("Recipient: %s", recipient)
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key_id = self._user_key(recipient)
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logging.info("Key ID: %s", key_id)
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if key_id:
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out_message = self._encrypt_message(in_message, key_id)
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# Delete Content-Transfer-Encoding if present to default to
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# "7bit" otherwise Thunderbird seems to hang in some cases.
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del out_message["Content-Transfer-Encoding"]
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else:
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logging.warn("No keys found, message will be sent unencrypted")
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out_message = copy.copy(in_message)
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self._add_zeyple_header(out_message)
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self._send_message(out_message, recipient)
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sent_messages.append(out_message)
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return sent_messages
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def _get_version_part(self):
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ret = email.mime.application.MIMEApplication(
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'Version: 1\n',
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'pgp-encrypted',
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email.encoders.encode_noop,
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)
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ret.add_header(
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'Content-Description',
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"PGP/MIME version identification",
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)
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return ret
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def _get_encrypted_part(self, payload):
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ret = email.mime.application.MIMEApplication(
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payload,
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'octet-stream',
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email.encoders.encode_noop,
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name="encrypted.asc",
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)
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ret.add_header('Content-Description', "OpenPGP encrypted message")
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ret.add_header(
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'Content-Disposition',
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'inline',
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filename='encrypted.asc',
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)
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return ret
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def _encrypt_message(self, in_message, key_id):
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if in_message.is_multipart():
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# get the body (after the first \n\n)
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payload = in_message.as_string().split("\n\n", 1)[1].strip()
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# prepend the Content-Type including the boundary
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content_type = "Content-Type: " + in_message["Content-Type"]
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payload = content_type + "\n\n" + payload
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message = email.message.Message()
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message.set_payload(payload)
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payload = message.get_payload()
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else:
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payload = in_message.get_payload()
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payload = encode_string(payload)
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quoted_printable = email.charset.Charset('ascii')
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quoted_printable.body_encoding = email.charset.QP
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message = email.mime.nonmultipart.MIMENonMultipart(
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'text', 'plain', charset='utf-8'
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)
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message.set_payload(payload, charset=quoted_printable)
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mixed = email.mime.multipart.MIMEMultipart(
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'mixed',
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None,
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[message],
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)
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# remove superfluous header
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del mixed['MIME-Version']
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payload = as_binary_string(mixed)
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encrypted_payload = self._encrypt_payload(payload, [key_id])
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version = self._get_version_part()
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encrypted = self._get_encrypted_part(encrypted_payload)
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out_message = copy.copy(in_message)
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out_message.preamble = "This is an OpenPGP/MIME encrypted " \
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"message (RFC 4880 and 3156)"
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if 'Content-Type' not in out_message:
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out_message['Content-Type'] = 'multipart/encrypted'
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else:
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out_message.replace_header(
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'Content-Type',
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'multipart/encrypted',
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)
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out_message.set_param('protocol', 'application/pgp-encrypted')
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out_message.set_payload([version, encrypted])
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return out_message
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def _encrypt_payload(self, payload, key_ids):
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"""Encrypts the payload with the given keys"""
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payload = encode_string(payload)
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plaintext = BytesIO(payload)
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ciphertext = BytesIO()
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self.gpg.armor = True
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recipient = [self.gpg.get_key(key_id) for key_id in key_ids]
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self.gpg.encrypt(recipient, gpgme.ENCRYPT_ALWAYS_TRUST,
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plaintext, ciphertext)
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return ciphertext.getvalue()
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def _user_key(self, email):
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"""Returns the GPG key for the given email address"""
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logging.info("Trying to encrypt for %s", email)
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keys = [key for key in self.gpg.keylist(email)]
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if keys:
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key = keys.pop() # NOTE: looks like keys[0] is the master key
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key_id = key.subkeys[0].keyid
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return key_id
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return None
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def _add_zeyple_header(self, message):
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if self.config.has_option('zeyple', 'add_header') and \
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self.config.getboolean('zeyple', 'add_header'):
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message.add_header(
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'X-Zeyple',
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"processed by {0} v{1}".format(__title__, __version__)
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)
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def _send_message(self, message, recipient):
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"""Sends the given message through the SMTP relay"""
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logging.info("Sending message %s", message['Message-id'])
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smtp = smtplib.SMTP(self.config.get('relay', 'host'),
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self.config.get('relay', 'port'))
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smtp.sendmail(message['From'], recipient, message.as_string())
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smtp.quit()
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logging.info("Message %s sent", message['Message-id'])
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if __name__ == '__main__':
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recipients = sys.argv[1:]
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# BBB: Python 2.7 support
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binary_stdin = sys.stdin.buffer if PY3K else sys.stdin
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message = binary_stdin.read()
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zeyple = Zeyple()
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zeyple.process_message(message, recipients)
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