client_session_present.py

#!/usr/bin/python

# Copyright (c) 2014 Roger Light <roger@atchoo.org>
#
# All rights reserved. This program and the accompanying materials
# are made available under the terms of the Eclipse Distribution License v1.0
# which accompanies this distribution. 
#
# The Eclipse Distribution License is available at 
#   http://www.eclipse.org/org/documents/edl-v10.php.
#
# Contributors:
#    Roger Light - initial implementation
# Copyright (c) 2014 Roger Light <roger@atchoo.org>
# All rights reserved.

# This demonstrates the session present flag when connecting.

import sys
try:
    import paho.mqtt.client as mqtt
except ImportError:
    # This part is only required to run the example from within the examples
    # directory when the module itself is not installed.
    #
    # If you have the module installed, just use "import paho.mqtt.client"
    import os
    import inspect
    cmd_subfolder = os.path.realpath(os.path.abspath(os.path.join(os.path.split(inspect.getfile( inspect.currentframe() ))[0],"../src")))
    if cmd_subfolder not in sys.path:
        sys.path.insert(0, cmd_subfolder)
    import paho.mqtt.client as mqtt

def on_connect(mqttc, obj, flags, rc):
    if obj == 0:
        print("First connection:")
    elif obj == 1:
        print("Second connection:")
    elif obj == 2:
        print("Third connection (with clean session=True):")
    print("    Session present: "+str(flags['session present']))
    print("    Connection result: "+str(rc))
    mqttc.disconnect()

def on_disconnect(mqttc, obj, rc):
    mqttc.user_data_set(obj+1)
    if obj == 0:
        mqttc.reconnect()

def on_log(mqttc, obj, level, string):
    print(string)

mqttc = mqtt.Client(client_id="asdfj", clean_session=False)
mqttc.on_connect = on_connect
mqttc.on_disconnect = on_disconnect
# Uncomment to enable debug messages
#mqttc.on_log = on_log
mqttc.user_data_set(0)
mqttc.connect("test.mosquitto.org", 1883, 60)

mqttc.loop_forever()

# Clear session
mqttc = mqtt.Client(client_id="asdfj", clean_session=True)
mqttc.on_connect = on_connect
mqttc.user_data_set(2)
mqttc.connect("test.mosquitto.org", 1883, 60)
mqttc.loop_forever()