serial_node.py

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#!/usr/bin/env python
 
 
 
__author__ = "mferguson@willowgarage.com (Michael Ferguson)"
 
import rospy
from rosserial_python import SerialClient, RosSerialServer
from serial import SerialException
from time import sleep
import multiprocessing
 
import sys
 
if __name__=="__main__":
    rospy.init_node("serial_node")
    rospy.loginfo("ROS Serial Python Node")
 
    port_name = rospy.get_param('~port','/dev/ttyUSB0')
    baud = int(rospy.get_param('~baud','57600'))
 
    # for systems where pyserial yields errors in the fcntl.ioctl(self.fd, TIOCMBIS, \
    # TIOCM_DTR_str) line, which causes an IOError, when using simulated port
    fix_pyserial_for_test = rospy.get_param('~fix_pyserial_for_test', False)
 
    # Allows for assigning local parameters for tcp_port and fork_server with
    # global parameters as fallback to prevent breaking changes 
    if(rospy.has_param('~tcp_port')):
        tcp_portnum = int(rospy.get_param('~tcp_port'))
    else:
        tcp_portnum = int(rospy.get_param('/rosserial_embeddedlinux/tcp_port', '11411'))
    
    if(rospy.has_param('~fork_server')):
        fork_server = rospy.get_param('~fork_server')
    else:
        fork_server = rospy.get_param('/rosserial_embeddedlinux/fork_server', False)
 
    # TODO: do we really want command line params in addition to parameter server params?
    sys.argv = rospy.myargv(argv=sys.argv)
    if len(sys.argv) >= 2 :
        port_name  = sys.argv[1]
    if len(sys.argv) == 3 :
        tcp_portnum = int(sys.argv[2])
 
    if port_name == "tcp" :
        server = RosSerialServer(tcp_portnum, fork_server)
        rospy.loginfo("Waiting for socket connections on port %d" % tcp_portnum)
        try:
            server.listen()
        except KeyboardInterrupt:
            rospy.loginfo("got keyboard interrupt")
        finally:
            rospy.loginfo("Shutting down")
            for process in multiprocessing.active_children():
                rospy.loginfo("Shutting down process %r", process)
                process.terminate()
                process.join()
            rospy.loginfo("All done")
 
    else :          # Use serial port
        while not rospy.is_shutdown():
            rospy.loginfo("Connecting to %s at %d baud" % (port_name,baud) )
            try:
                client = SerialClient(port_name, baud, fix_pyserial_for_test=fix_pyserial_for_test)
                client.run()
            except KeyboardInterrupt:
                break
            except SerialException:
                sleep(1.0)
                continue
            except OSError:
                sleep(1.0)
                continue
            except:
                rospy.logwarn("Unexpected Error: %s", sys.exc_info()[0])
                client.port.close()
                sleep(1.0)
                continue