GMail Important Mails Notifier

#!/usr/bin/env python
# -*- coding: utf-8 -*-
"""GMail Important Mails Notifier

A very simple GMail IMAP client which retrieves
only new **important** messages and displays a
notification using pynotify module.
"""
import time
import imaplib
import pynotify
import getpass
from email.header import decode_header
from email.parser import Parser
from optparse import OptionParser

__author__ = "Andrés Gattinoni <andresgattinoni@gmail.com>"
__version__ = "0.1"
__host = 'imap.gmail.com'
__port = 993
__interval = 60*2

class Client(object):
    """Very simple IMAP client"""
    def __init__ (self, host, port, username, password):
        """Constructor"""
        self._interval = 0
        # Connector
        self.client =  imaplib.IMAP4_SSL(host, port)
        # Login
        if not self.client.login(username, password):
            raise Exception("Invalid login")
        # Attempt to select the Important label
        status, data = self.client.select('[Gmail]/Important')
        if status != 'OK':
            raise Exception("Label [Gmail]/Important not found")

        # Attempt to init pynotify
        if not pynotify.init("GMail Important Messages"):
            raise Exception("Failed to initialize pynotify module")

    def set_interval (self, time):
        """Define a new check interval"""
        self._interval = int(time)

    def start (self):
        """Main loop"""
        lst = []
        while True:
            try:
                status, data = self.client.search(None, '(UNSEEN)')
                if status == 'OK':
                    if data[0] != '':
                        for msg_id in sorted(data[0].split()):
                            # If we have a new message
                            # fetch it and append it to the list
                            if msg_id != '' and msg_id not in lst:
                                lst.append(msg_id)
                                status, data = self.client.fetch(msg_id, '(RFC822)')
                                # Mark as unread
                                self.client.store(msg_id, '-FLAGS', '\\Seen')
                                self.client.store(msg_id, '-FLAGS', '\\Recent')
                                if status == 'OK':
                                    msg = Parser().parsestr(data[0][1])
                                    self.notify(self.get_header(msg, 'From'), \
                                                self.get_header(msg, 'Subject'))
                                else:
                                    print "Failed to fetch message #%s" % str(msg_id)
                else:
                    raise Exception("Failed to retrieve new important messages")
                    break
                time.sleep(self._interval)
            except KeyboardInterrupt:
                break

    def notify (self, title, msg):
        """Notifies new messages"""
        pynotify.Notification(title, msg).show()

    def get_header (self, msg, header):
        """Gets a header from a message"""
        header = decode_header(msg.get(header))
        if (header[0][1]):
            return unicode(header[0][0], header[0][1]).encode('utf8')
        else:
            return header[0][0]

if __name__ == '__main__':
    """Starting point of the application.
    Defines an option parser and starts the client loop"""
    parser = OptionParser(usage='%prog [options]', \
                          version=__version__, \
                          description="Simple script for Important messages notifications")
    parser.add_option('-u', '--user', dest='user', \
                      help='Gmail\'s username', \
                      metavar='USERNAME', default=None)
    parser.add_option('-p', '--password', dest='password', \
                      help='Gmail\'s password', \
                      metavar='PASSWORD', default=None)
    parser.add_option('-H', '--host', dest='host', \
                      help='IMAP hostname (default: %s)' % __host, \
                      metavar='HOSTNAME', default=__host)
    parser.add_option('-P', '--port', dest='port', \
                      help='IMAP port (default: %d)' % __port, \
                      metavar='PORT', default=__port)
    parser.add_option('-t', '--time', dest='time', \
                      help='Check interval (default: %d secs)' % __interval, \
                      metavar='TIME', default=__interval)

    # Parse options and do some input checking
    (option, args) = parser.parse_args()

    if option.user is None:
        option.user = raw_input('Username: ')

    if option.password is None:
        option.password = getpass.getpass('Password: ')

    client = Client(option.host, option.port, option.user, option.password)
    client.set_interval(option.time)
    client.start()