subtopic_forwarder.py

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#! /usr/bin/python
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#* Author: Eitan Marder-Eppstein
#***********************************************************
PKG = 'move_base'
NAME = 'subtopic_forwarder'

import roslib; roslib.load_manifest(PKG)

import rospy
import sys
import rostopic
from std_msgs.msg import *
from roslib.message import Message

class SubtopicForwarder(object):
  def __init__(self, topic, remapped_topic):
    topic_class, real_topic, msg_eval = rostopic.get_topic_class(topic)
    try:
      rospy.Subscriber(real_topic, topic_class, self.callback, (remapped_topic, msg_eval))
    except ValueError: pass

  def callback(self, data, args):
    remapped_topic, msg_eval = args

    #make sure to check if we have a subtopic or just a topic
    remapped_msg = msg_eval != None and msg_eval(data) or data

    if not issubclass(type(remapped_msg), Message):
      rospy.logerr("Sorry, forwarding primitive types, in this case a %s, is not supported by this tool :(", type(remapped_msg))
      return 
        
    remap_pub = rospy.Publisher(remapped_topic, type(remapped_msg))
    remap_pub.publish(remapped_msg)

if __name__ == '__main__':
  if len(sys.argv) < 3:
    print "You are uinsg this tool wrong, usage is:" 
    print "subtopic_forwarder [source_topic] [destination_topic]"
    sys.exit(-1)

  rospy.init_node(NAME, anonymous=True)

  topic = rospy.resolve_name(sys.argv[1])
  remapped_topic = rospy.resolve_name(sys.argv[2])
  sf = SubtopicForwarder(topic, remapped_topic)

  rospy.spin()