Publish "card swiped" event via MQTT

components/smart-home-automation/MQTT-protocol/README.md

@@ -34,8 +34,16 @@ Phoniebox' MQTT client will do the following things:
 2. at shutdown send state info to
    - `phoniebox/state` (offline)
 3. periodically send *all* attributes to `phoniebox/attribute/$attributeName` (this interval can be defined through `refreshIntervalPlaying` and `refreshIntervalIdle` in the `SETTINGS` section)
-4. listen for attribute requests on `phoniebox/get/$attribute`
-5. listen for commands on `phoniebox/cmd/$command` (if a command needs a parameter it has to be provided via payload)
+4. send specific events to `phoniebox/event/$eventName` right away
+5. listen for attribute requests on `phoniebox/get/$attribute`
+6. listen for commands on `phoniebox/cmd/$command` (if a command needs a parameter it has to be provided via payload)
+
+## Topic: phoniebox/event/$event
+This is a read-only topic. The following events trigger immediate messages through this topic:
+
+- card_swiped
+
+Use these topics to get notified of time-critical events right away rather than having to wait for the periodic send of all attributes or requesting an attribute through the get topic. Currently the only event triggering a message is the "card_swiped" event with the obvious use-case of letting your smart home react upon swiped cards. These cards needn't be configured in Phoniebox as the MQTT daemon will just relay any swiped card to the MQTT server. So it's possible to have a "dim lights" card that will not trigger any Phoniebox action but is picked up by your smart home to dim the lights.
 
 ## Topic: phoniebox/get/$attribute
 MQTT clients can (additionally to the periodic updates) request an attribute of Phoniebox. Sending an empty payload to `phoniebox/get/volume` will trigger Phoniebox' MQTT client to fetch the current volume from MPD and send the result to `phoniebox/attribute/volume`. 
@@ -114,7 +122,7 @@ Sending empty payload to `phoniebox/cmd/help` will be responded by a list of all
 Install missing python packages for MQTT:
 
 ~~~
-sudo pip3 install paho-mqtt
+sudo python3 -m pip install --upgrade --force-reinstall -q -r requirements.txt
 ~~~
 
 All relevant files can be found in the folder:

components/smart-home-automation/MQTT-protocol/daemon_mqtt_client.py

@@ -2,12 +2,13 @@
 
 import paho.mqtt.client as mqtt
 import os, subprocess, re, ssl, time, datetime
-
+import inotify.adapters
+from threading import *
 
 # ----------------------------------------------------------
 #  Prerequisites
 # ----------------------------------------------------------
-# pip3 install paho-mqtt
+# pip3 install paho-mqtt inotify
 
 
 # ----------------------------------------------------------
@@ -43,6 +44,29 @@
 arAvailableAttributes = ['volume', 'mute', 'repeat', 'random', 'state', 'file', 'artist', 'albumartist', 'title', 'album', 'track', 'elapsed', 'duration', 'trackdate', 'last_card', 'maxvolume', 'volstep', 'idletime', 'rfid', 'gpio', 'remaining_stopafter', 'remaining_shutdownafter', 'remaining_idle', 'throttling', 'temperature']
 
 
+def watchForNewCard():
+    i = inotify.adapters.Inotify()
+    i.add_watch(path + "/../settings/Latest_RFID")
+
+    # wait for inotify events
+    for event in i.event_gen(yield_nones=False):
+        if event is not None:
+            # fetch event attributes
+            (e_header, e_type_names, e_path, e_filename) = event
+
+            # file was closed and written => a new card was swiped
+            if "IN_CLOSE_WRITE" in e_type_names:
+                # fetch card ID
+                cardid = readfile(path + "/../settings/Latest_RFID")
+
+                # publish event "card_swiped"
+                client.publish(mqttBaseTopic + "/event/card_swiped", payload=cardid)
+                print(" --> Publishing event card_swiped = " + cardid)
+
+                # process all attributes
+                processGet("all")
+
+
 def on_connect(client, userdata, flags, rc):
     if rc == 0:
         print("Connection established.")
@@ -386,6 +410,11 @@ def fetchData():
 print("Subscribing to " + mqttBaseTopic + "/get/#")
 client.subscribe(mqttBaseTopic + "/get/#")
 
+# register thread for watchForNewCard
+tWatchForNewCard = Thread(target=watchForNewCard)
+tWatchForNewCard.setDaemon(True)
+tWatchForNewCard.start()
+
 # start endless loop
 client.loop_start()
 while True:

components/smart-home-automation/MQTT-protocol/requirements.txt

@@ -0,0 +1,5 @@
+# MQTT daemon related requirements
+# you need to install these with `sudo python3 -m pip install --upgrade --force-reinstall -q -r requirements.txt`
+
+paho-mqtt
+inotify