A Python script that (re-)sends all messages in mbox files with From/To/Cc/Bcc as specified in the messages headers

mbox_send.py

#!/usr/bin/env python

"""\
A command-line utility that can (re)send all messages in an mbox file
with options for controlling the rate at which they are sent, etc.
"""

# This script is based on a gist on github, see
#   https://gist.github.com/sbeyer/8230267
#
# For the origin of the script see
#   https://github.com/wojdyr/fityk/wiki/MigrationToGoogleGroups

import sys
import os
import time
import mailbox
import email
import smtplib

from copy import copy
from optparse import OptionParser, make_option
from getpass import getpass

# Set some defaults

defBcc = []
defChunkSize = 100
defChunkDelay = 30.0
defUser = None
defHost = 'localhost'
defPort = 25
defCount = -1
defStart = -1

# define the command line options

option_list = [
    make_option('--add-bcc', action='append', metavar='ADDRESSES', dest='bccAddresses', default=defBcc,
        help='Address that every mail should be sent to, additionally. May be repeated.'),

    make_option('--host', dest='host', default=defHost,
        help='Hostname where SMTP server is running. [default: %s]' % defHost),

    make_option('--port', type='int', dest='port', default=defPort,
        help='Port number to use for connecting to SMTP server. [default: %d]' % defPort),

    make_option('--user', dest='user', default=defUser,
        help='Username for SMTP server. (Will prompt for password.)'),

    make_option('--chunk', type='int', dest='chunkSize', default=defChunkSize,
        help='How many messages to send in each batch before pausing. [default: %d]' % defChunkSize),

    make_option('--pause', type='float', dest='chunkDelay', default=defChunkDelay,
        help='How many seconds to delay between chunks. [default: %f]' % defChunkDelay),

    make_option('--count', type='int', dest='count', default=defCount,
        help='How many messages to send before exiting the tool. [default: all messages in mbox]'),

    make_option('--start', type='int', dest='start', default=defStart,
        help='Which message number to start with. [default: where the tool left off the last time, or zero]'),
    ]

#---------------------------------------------------------------------------

def get_hwm(hwmfile):
    if not os.path.exists(hwmfile):
        return -1
    hwm = int(open(hwmfile).read())
    return hwm

def set_hwm(hwmfile, count):
    f = open(hwmfile, 'w')
    f.write(str(count))
    f.close()

def addresses(string):
    if string:
        return [x[1] for x in email.utils.getaddresses([string])]
    return []

def main(args):
    if sys.version_info < (2,5):
        print('Python 2.5 or better is required.')
        sys.exit(1)

    # Parse the command line args
    parser = OptionParser(
        usage='%prog [options] mbox_file(s)',
        description=__doc__,
        version='%prog 20140103',
        option_list=option_list)

    options, arguments = parser.parse_args(args)

    if not arguments:
        parser.error('At least one mbox file is required')

    smtpPassword = None
    if options.user:
        smtpPassword = getpass() # implies using TLS

    # process the mbox file(s)
    for mboxfile in arguments:
        print('Opening %s...' % mboxfile)
        mbox = mailbox.mbox(mboxfile)
        totalInMbox = len(mbox)
        print('Total messages in mbox: %d' % totalInMbox)

        hwmfile = mboxfile + '.hwm'
        print('Storing last message processed in %s' % hwmfile)
        start = get_hwm(hwmfile)
        if options.start != -1:
            start = options.start
        start += 1
        print('Starting with message #%d' % start)

        totalSent = 0
        current = start

        # Outer loop continues until either the whole mbox or options.count
        # messages have been sent,
        while (current < totalInMbox and
            (totalSent < options.count or options.count == -1)):

            # Inner loop works one chunkSize number of messages at a time,
            # pausing and reconnecting to the SMTP server for each chunk.
            print('Connecting to SMTP(%s, %d)' % (options.host, options.port))
            smtp = smtplib.SMTP(options.host, options.port)

            if options.user: # use TLS
                print('Logging in as %s' % options.user)
                smtp.ehlo()
                smtp.starttls()
                smtp.ehlo()
                smtp.login(options.user, smtpPassword)

            chunkSent = 0
            while chunkSent < options.chunkSize:
                msg = mbox[current]
                print('Processing message %d: %s' % (current, msg['Subject']))

                try:
                    # Here is where we actually send the message
                    fromAddress = addresses(msg['From'])[0]
                    toAddresses = copy(options.bccAddresses)
                    toAddresses += addresses(msg['To'])
                    toAddresses += addresses(msg['Cc'])
                    toAddresses += addresses(msg['Bcc'])
                    smtp.sendmail(fromAddress, toAddresses, msg.as_string())

                    set_hwm(hwmfile, current) # set new 'high water mark'
                    current += 1
                    totalSent += 1
                    chunkSent += 1
                    if (current >= totalInMbox or
                        (totalSent >= options.count and options.count != -1)):
                        break
                except smtplib.SMTPServerDisconnected as e:
                    print('Error: %s' % str(e))
                    del smtp
                    print('Pausing for %f seconds...' % options.chunkDelay)
                    time.sleep(options.chunkDelay)
                    print('')
                    break
            else:
                smtp.quit()
                del smtp
                print('Pausing for %f seconds...' % options.chunkDelay)
                time.sleep(options.chunkDelay)
                print('')

    print('Goodbye')

#---------------------------------------------------------------------------

if __name__ == '__main__':
    main(sys.argv[1:])