Simple Mavlink Reader in Python using pymavlink

gistfile1.py

#!/usr/bin/env python

import sys, os
from optparse import OptionParser

# tell python where to find mavlink so we can import it
sys.path.append(os.path.join(os.path.dirname(os.path.realpath(__file__)), '../mavlink'))
from pymavlink import mavutil

def handle_heartbeat(msg):
	mode = mavutil.mode_string_v10(msg)
	is_armed = msg.base_mode & mavutil.mavlink.MAV_MODE_FLAG_SAFETY_ARMED
	is_enabled = msg.base_mode & mavutil.mavlink.MAV_MODE_FLAG_GUIDED_ENABLED

def handle_rc_raw(msg):
	channels = (msg.chan1_raw, msg.chan2_raw, msg.chan3_raw, msg.chan4_raw, 
			msg.chan5_raw, msg.chan6_raw, msg.chan7_raw, msg.chan8_raw)

def handle_hud(msg):
	hud_data = (msg.airspeed, msg.groundspeed, msg.heading, 
				msg.throttle, msg.alt, msg.climb)
	print "Aspd\tGspd\tHead\tThro\tAlt\tClimb"
	print "%0.2f\t%0.2f\t%0.2f\t%0.2f\t%0.2f\t%0.2f" % hud_data

def handle_attitude(msg):
	attitude_data = (msg.roll, msg.pitch, msg.yaw, msg.rollspeed, 
				msg.pitchspeed, msg.yawspeed)
	print "Roll\tPit\tYaw\tRSpd\tPSpd\tYSpd"
	print "%0.2f\t%0.2f\t%0.2f\t%0.2f\t%0.2f\t%0.2f\t" % attitude_data

def read_loop(m):

	while(True):

		# grab a mavlink message
		msg = m.recv_match(blocking=False)
		if not msg:
			return

		# handle the message based on its type
		msg_type = msg.get_type()
		if msg_type == "BAD_DATA":
			if mavutil.all_printable(msg.data):
				sys.stdout.write(msg.data)
				sys.stdout.flush()
		elif msg_type == "RC_CHANNELS_RAW": 
			handle_rc_raw(msg)
		elif msg_type == "HEARTBEAT":
			handle_heartbeat(msg)
		elif msg_type == "VFR_HUD":
			handle_hud(msg)
		elif msg_type == "ATTITUDE":
			handle_attitude(msg)
		
def main():

	# read command line options
	parser = OptionParser("readdata.py [options]")
	parser.add_option("--baudrate", dest="baudrate", type='int',
					  help="master port baud rate", default=115200)
	parser.add_option("--device", dest="device", default=None, help="serial device")
	parser.add_option("--rate", dest="rate", default=4, type='int', help="requested stream rate")
	parser.add_option("--source-system", dest='SOURCE_SYSTEM', type='int',
					  default=255, help='MAVLink source system for this GCS')
	parser.add_option("--showmessages", dest="showmessages", action='store_true',
					  help="show incoming messages", default=False)
	(opts, args) = parser.parse_args()
	
	if opts.device is None:
		print("You must specify a serial device")
		sys.exit(1)

	# create a mavlink serial instance
	master = mavutil.mavlink_connection(opts.device, baud=opts.baudrate)

	# wait for the heartbeat msg to find the system ID
	master.wait_heartbeat()

	# request data to be sent at the given rate
	master.mav.request_data_stream_send(master.target_system, master.target_component, 
		mavutil.mavlink.MAV_DATA_STREAM_ALL, opts.rate, 1)

	# enter the data loop
	read_loop(master)


if __name__ == '__main__':
	main()

Sir, this is very well written and easy to understand. You have saved me many hours of work. Thank you!
I do have a question though. Why does this script only extract a small portion of the available messages. When I run it with a print statement to print everything 'print (master.messages)', these are all that I see.
{'LOCAL_POSITION_NED':
<pymavlink.dialects.v10.ardupilotmega.MAVLink_local_position_ned_message object at 0x758ac050>, 'TERRAIN_REPORT':

<pymavlink.dialects.v10.ardupilotmega.MAVLink_terrain_report_message object at 0x758ac990>, 'ATTITUDE':

<pymavlink.dialects.v10.ardupilotmega.MAVLink_attitude_message object at 0x758ac650>, 'HEARTBEAT':

<pymavlink.dialects.v10.ardupilotmega.MAVLink_heartbeat_message object at 0x758ac330>, 'HOME':

<pymavlink.dialects.v10.ardupilotmega.MAVLink_gps_raw_int_message object at 0x758acb50>, 'MISSION_CURRENT':

<pymavlink.dialects.v10.ardupilotmega.MAVLink_mission_current_message object at 0x758acdf0>, 'RAW_IMU':

<pymavlink.dialects.v10.ardupilotmega.MAVLink_raw_imu_message object at 0x758ac190>, 'GPS_RAW_INT':

<pymavlink.dialects.v10.ardupilotmega.MAVLink_gps_raw_int_message object at 0x758ac430>, 'NAV_CONTROLLER_OUTPUT':

<pymavlink.dialects.v10.ardupilotmega.MAVLink_nav_controller_output_message object at 0x758ac0f0>, 'VFR_HUD':

<pymavlink.dialects.v10.ardupilotmega.MAVLink_vfr_hud_message object at 0x758acfd0>, 'MEMINFO':

<pymavlink.dialects.v10.ardupilotmega.MAVLink_meminfo_message object at 0x758ac810>, 'HWSTATUS':

<pymavlink.dialects.v10.ardupilotmega.MAVLink_hwstatus_message object at 0x758ac530>, 'VIBRATION':

<pymavlink.dialects.v10.ardupilotmega.MAVLink_vibration_message object at 0x758ac4d0>, 'SCALED_IMU2':

<pymavlink.dialects.v10.ardupilotmega.MAVLink_scaled_imu2_message object at 0x758acf10>, 'BAD_DATA':

<pymavlink.dialects.v10.ardupilotmega.MAVLink_bad_data object at 0x759526b0>, 'SENSOR_OFFSETS':

<pymavlink.dialects.v10.ardupilotmega.MAVLink_sensor_offsets_message object at 0x758accf0>, 'SYS_STATUS':

<pymavlink.dialects.v10.ardupilotmega.MAVLink_sys_status_message object at 0x758acaf0>, 'SCALED_PRESSURE':

<pymavlink.dialects.v10.ardupilotmega.MAVLink_scaled_pressure_message object at 0x758acd30>, 'GLOBAL_POSITION_INT':

<pymavlink.dialects.v10.ardupilotmega.MAVLink_global_position_int_message object at 0x758ac8b0>, 'AHRS':

<pymavlink.dialects.v10.ardupilotmega.MAVLink_ahrs_message object at 0x758aca90>, 'POWER_STATUS':

<pymavlink.dialects.v10.ardupilotmega.MAVLink_power_status_message object at 0x758ac2b0>, 'SYSTEM_TIME':

<pymavlink.dialects.v10.ardupilotmega.MAVLink_system_time_message object at 0x758ac210>, 'EKF_STATUS_REPORT':

<pymavlink.dialects.v10.ardupilotmega.MAVLink_ekf_status_report_message object at 0x758aca10>, 'MAV':

<pymavlink.mavutil.mavserial object at 0x75952910>, 'AHRS3':
<pymavlink.dialects.v10.ardupilotmega.MAVLink_ahrs3_message object at 0x758acf50>, 'AHRS2':

<pymavlink.dialects.v10.ardupilotmega.MAVLink_ahrs2_message object at 0x758acc50>, 'SERVO_OUTPUT_RAW':

<pymavlink.dialects.v10.ardupilotmega.MAVLink_servo_output_raw_message object at 0x758ac8f0>, 'RC_CHANNELS_RAW':

<pymavlink.dialects.v10.ardupilotmega.MAVLink_rc_channels_raw_message object at 0x758ac3d0>, 'POSITION_TARGET_GLOBAL_INT':

<pymavlink.dialects.v10.ardupilotmega.MAVLink_position_target_global_int_message object at 0x758acbb0>, 'WIND':

<pymavlink.dialects.v10.ardupilotmega.MAVLink_wind_message object at 0x758acf90>}

why is there a master.wait_heartbeart()?

And MAV_DATA_STREAM_ALL is said to be deprecated as per new MAVLink definitions i went through.I don't have a clue what its consequence is.
And can you help me out?

Instead of MAV_DATA_STREAM_ALL, use MAV_DATA_STREAM_POSITION or one of the others, It will work.

How do I find the serial device option in this. Can you please add an example of usage?
Thanks.