Merge branch '30-frontend' into mbl-next

Reviewed-on: #57
Reviewed-by: Stefan Kratochwil <kratochwil-la@gmx.de>

software/src/app.py

@@ -190,3 +190,6 @@ class PlayerApp:
         self.timer_manager.cancel(self.onIdleTimeout)
         self.leds.set_state(self.leds.PLAYING)
         self.playing = True
+
+    def get_nfc(self):
+        return self.nfc

software/src/webserver.py

@@ -11,13 +11,22 @@ webapp = Microdot()
 server = None
 config = None
 app = None
+nfc = None
 
 
 def start_webserver(config_, app_):
-    global server, config, app
+    global server, config, app, nfc
     server = asyncio.create_task(webapp.start_server(port=80))
     config = config_
     app = app_
+    nfc = app.get_nfc()
+
+
+@webapp.before_request
+async def before_request_handler(request):
+    if request.method in ['PUT', 'POST'] and app.is_playing():
+        return "Cannot write to device while playback is active", 503
+    app.reset_idle_timeout()
 
 
 @webapp.before_request
@@ -66,6 +75,12 @@ async def config_put(request):
     return '', 204
 
 
+@webapp.route('/api/v1/last_tag_uid', methods=['GET'])
+async def last_tag_uid_get(request):
+    tag, _ = nfc.get_last_uid()
+    return {'tag': tag}
+
+
 @webapp.route('/', methods=['GET'])
 async def root_get(request):
     return redirect('/index.html')