MQTT: Add example to README and Python test client (#495)

README.md

@@ -173,6 +173,7 @@ Examples:
 | `rtl_433 -a -t` | Will run in analyze mode and save a test file per detected signal (gfile###.data). Format is uint8, 2 channels.
 | `rtl_433 -r file_name` | Play back a saved data file. 
 | `rtl_433 file_name` | Will save everything received from the rtl-sdr during the session into a single file. The saves file may become quite large depending on how long rtl_433 is left running. Note: saving signals into individual files wint `rtl_433 -a -t` is preferred.
+| `rtl_433 -F json -U | mosquitto_pub -t home/rtl_433 -l` | Will pipe the output to network as JSON formatted MQTT messages. A test MQTT client can be found in `tests/mqtt_rtl_433_test.py`.
 
 This software is mostly useable for developers right now.
 

tests/mqtt_rtl_433_test.py

@@ -0,0 +1,107 @@
+#!/usr/bin/env python3
+""" MQTT test client for receiving rtl_433 JSON data
+
+Example program for receiving and parsing sensor data from rtl_433 sent
+as MQTT network messages. Recommended way of sending rtl_433 data on network is:
+
+$ rtl_433 -F json -U | mosquitto_pub -t home/rtl_433 -l
+
+An MQTT broker e.g. 'mosquitto' must be running on local compputer
+
+Copyright (C) 2017 Tommy Vestermark
+This program is free software; you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation; either version 2 of the License, or
+(at your option) any later version.
+"""
+
+import multiprocessing as mp
+import logging
+import paho.mqtt.client as mqtt
+import json
+import sys, os
+import time, datetime
+
+MQTT_SERVER = "127.0.0.1"
+MQTT_TOPIC_PREFIX = "home/rtl_433"
+TIMEOUT_STALE_SENSOR = 600      # Seconds before showing a timeout indicator
+
+#log = logging.getLogger()  # Single process logger
+log = mp.log_to_stderr()    # Multiprocessing capable logger
+mqtt_client = mqtt.Client("RTL_433_Test")
+
+sensor_state = dict()   # Dictionary containing accumulated sensor state
+
+
+def print_sensor_state():
+    """ Print accumulated sensor state """
+    time_now = datetime.datetime.utcnow().replace(microsecond=0)
+    print("\nUpdate per {} UTC".format(time_now.isoformat(sep=' ')))
+    for model in sensor_state:
+        print(model)
+        for ID in sensor_state[model]:
+            data = sensor_state[model][ID]['data'].copy()
+            timestamp = data.pop('time')
+            timedelta = (time_now-timestamp).total_seconds()
+            indicator = "*" if (timedelta < 2) else "~" if (timedelta > TIMEOUT_STALE_SENSOR) else " "   # Indicator for new and stale data
+            print("  ID {:5} {}{} {}".format(ID, timestamp.isoformat(sep=' '), indicator, data))
+    sys.stdout.flush()  # Print in real-time
+
+
+def on_connect(client, userdata, rc):
+    """ Callback for when the client receives a CONNACK response from the server. """
+    log.info("MQTT Connection: " + mqtt.connack_string(rc))
+    if rc != 0:
+        log.error("Could not connect. RC: " + str(rc))
+        exit()
+    # Subscribing in on_connect() means that if we lose the connection and reconnect then subscriptions will be renewed.
+    client.subscribe(MQTT_TOPIC_PREFIX + "/#")
+
+
+def on_disconnect(client, userdata, rc):
+    if rc != 0:
+        log.error("Unexpected disconnection. RC: " + str(rc))
+
+
+def on_message(client, userdata, msg):
+    """ Callback for when a PUBLISH message is received from the server. """
+    if msg.topic.startswith(MQTT_TOPIC_PREFIX):
+        try:
+            # Decode JSON payload
+            d = json.loads(msg.payload.decode())
+        except:
+            log.warning("JSON decode error: " + msg.payload.decode())
+            return
+
+        # Convert time string to datetime object
+        time_str = d.get('time', "0000-00-00 00:00:00")
+        time_utc = datetime.datetime.strptime(time_str, "%Y-%m-%d %H:%M:%S")
+        d['time'] = time_utc
+        # Update sensor_state
+        sensor_model = d.pop('model', 'unknown')
+        sensor_id = d.pop('id', 0)
+        sensor_state.setdefault(sensor_model,{}).setdefault(sensor_id,{})['data'] = d
+        print_sensor_state()
+    else:
+        log.info("Uknown topic: " + msg.topic + "\t" + msg.payload.decode())
+
+
+# Setup MQTT client
+mqtt_client.on_connect = on_connect
+mqtt_client.on_disconnect = on_disconnect
+mqtt_client.on_message = on_message
+mqtt_client.connect(MQTT_SERVER)
+mqtt_client.loop_start()
+
+
+def main():
+    """MQTT Test Client"""
+    log.setLevel(logging.INFO)
+    log.info("MQTT RTL_433 Test Client")
+
+    while True:
+        time.sleep(1)
+
+
+if __name__ == "__main__":
+    main()