Opens a rosbag & shows connection information on all topics. Requires a patched `rosbag` package.

show_bag_headers.py

#!/usr/bin/env python2
from __future__ import print_function

import sys
from rosbag.bag import Bag

def main():
    if len(sys.argv) != 2:
        print ('usage: {script} <bagfile>'.format(script=sys.argv[0]))
        sys.exit(-1)
    inbag = Bag(sys.argv[1], 'r')
    headers = {}
    for topic, _, _, conn_header in inbag.read_messages(raw=True, return_connection_header=True):
        headers[topic] = conn_header

    for topic, header in headers.iteritems():
        print ('{topic}: {header}'.format(topic=topic, header=header))
    inbag.close()

if __name__ == '__main__':
   main()