A Python program to listen to your devices with MQTT

Application Development
8

I have improved the code a bit to work in Python3 and provide a simple CSV output showing packages received and signal strengths for each gateway.

Output example: > 2018-04-15T13:52:31.521984942Z, drone-mapper-new, 319, eui-3535303229005f00, -37, {‘alt’: 252, ‘lat’: 46.565055642429314, ‘lon’: 15.658404568338653, ‘hdop’: 2.2}

# https://www.thethingsnetwork.org/forum/t/a-python-program-to-listen-to-your-devices-with-mqtt/9036/6
# Get data from MQTT server
# Run this with python 3, install paho.mqtt prior to use

import paho.mqtt.client as mqtt
import json
import base64

APPEUI = "70B3D57EF00069A3"
APPID  = "my_second_lora_app"
PSW    = 'ttn-account-v2.<lots-of-chars>'

#Call back functions

# gives connection message
def on_connect(mqttc, mosq, obj,rc):
    print("Connected with result code:"+str(rc))
    # subscribe for all devices of user
    mqttc.subscribe('+/devices/+/up')

# gives message from device
def on_message(mqttc,obj,msg):
    try:
        #print(msg.payload)
        x = json.loads(msg.payload.decode('utf-8'))
        device = x["dev_id"]
        counter = x["counter"]
        payload_raw = x["payload_raw"]
        payload_fields = x["payload_fields"]
        datetime = x["metadata"]["time"]
        gateways = x["metadata"]["gateways"]
        # print for every gateway that has received the message and extract RSSI
        for gw in gateways:
            gateway_id = gw["gtw_id"]
            rssi = gw["rssi"]
            print(datetime + ", " + device + ", " + str(counter) + ", "+ gateway_id + ", "+ str(rssi) + ", " + str(payload_fields))
    except Exception as e:
        print(e)
        pass

def on_publish(mosq, obj, mid):
    print("mid: " + str(mid))

def on_subscribe(mosq, obj, mid, granted_qos):
    print("Subscribed: " + str(mid) + " " + str(granted_qos))

def on_log(mqttc,obj,level,buf):
    print("message:" + str(buf))
    print("userdata:" + str(obj))

mqttc= mqtt.Client()
# Assign event callbacks
mqttc.on_connect=on_connect
mqttc.on_message=on_message

mqttc.username_pw_set(APPID, PSW)
mqttc.connect("eu.thethings.network",1883,60)

# and listen to server
run = True
while run:
    mqttc.loop()
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