Question about callback function

[IROS]

how to read message from subscriber in service callback function?

[ptvphongtn93]

in section “Unit 5 Services in ROS: Clients” has a example call service from client
Python Program: simple_service_client.py

#! /usr/bin/env python

import rospy
# Import the service message used by the service /trajectory_by_name
from trajectory_by_name_srv.srv import TrajByName, TrajByNameRequest
import sys

# Initialise a ROS node with the name service_client
rospy.init_node('service_client')
# Wait for the service client /trajectory_by_name to be running
rospy.wait_for_service('/trajectory_by_name')
# Create the connection to the service
traj_by_name_service = rospy.ServiceProxy('/trajectory_by_name', TrajByName)
# Create an object of type TrajByNameRequest
traj_by_name_object = TrajByNameRequest()
# Fill the variable traj_name of this object with the desired value
traj_by_name_object.traj_name = "release_food"
# Send through the connection the name of the trajectory to be executed by the robot
result = traj_by_name_service(traj_by_name_object)
# Print the result given by the service called
print(result)

At final line: print(result), this is print respond message from server. If you know structure of respond message, you can analysis and reuse for many purpose
Please see example 5.6 : How to know the structure of the service message used by the service? to look up structure of message
please respond if i mistake your mean

[IROS]

Thanks for answer, but this answer is not what I want What I mean is that there’s a problem when using two kind callback function in one python file. If so how to read subscriber message in service callback function?

[bayodesegun]

Please provide more context so we can help you.

• What unit are you on?
• What exercise are you trying to solve?