Filter raw protocol messages from Pidgin debug log (`pidgin -d`)

filter_messages_from_pidgin_log.py

#/usr/bin/env python2

from __future__ import print_function
from sys import stdin, stderr, stdout
import re

message = []
message_started = message_ended = None

for line in stdin:    
    m = re.match(r'MESSAGE (START|END) (.+)$', line)
    if m:
        if not message_started and m.group(1)=='START':
            stderr.write(line)
            message_started = m.group(2)
        elif message_started==m.group(2) and m.group(1)=='END':
            stderr.write(line)
            message_ended = True
        else:
            raise RuntimeError, "Unexpected line %s while in message %s" % (line, message_started)

    if message_started:
        message.append(line)

    if message_ended:
        stdout.writelines(message)
        stdout.write('----------------------------------------\n')
        message = []
        message_started = message_ended = None