always return content type application/json

- Reset the app idle timer when interacting with the webapp, so that the
  device does not turn off while the web ui is used.

- Handle denying put/post while playback is active centrally in the
  before_request handler, so that it does not need to be copy/pasted
  into every request handler.

Signed-off-by: Matthias Blankertz <matthias@blankertz.org>

software/src/app.py

@@ -116,6 +116,10 @@ class PlayerApp:
             # Check again in a minute
             self.timer_manager.schedule(time.ticks_ms() + self.idle_timeout_ms, self.onIdleTimeout)
 
+    def reset_idle_timeout(self):
+        if not self.playing:
+            self.timer_manager.schedule(time.ticks_ms() + self.idle_timeout_ms, self.onIdleTimeout)
+
     def is_playing(self) -> bool:
         return self.playing
 
@@ -186,3 +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/utils/timer.py

@@ -50,29 +50,36 @@ class TimerManager(object):
         heapq.heapify(self.timers)
         return i
 
+    def _next_timeout(self):
+        if len(self.timers) == 0:
+            if self.timer_debug:
+                print("timer: worker: queue empty")
+            return None
+        cur_nearest = self.timers[0][0]
+        next_timeout = cur_nearest - time.ticks_ms()
+        if self.timer_debug:
+            if next_timeout > 0:
+                print(f"timer: worker: next is {self.timers[0]}, sleep {next_timeout} ms")
+            else:
+                print(f"timer: worker: {self.timers[0]} elapsed @{cur_nearest}, delay {-next_timeout} ms")
+        return next_timeout
+
+    async def _wait(self, timeout):
+        try:
+            await asyncio.wait_for_ms(self.worker_event.wait(), timeout)
+            if self.timer_debug:
+                print("timer: worker: event")
+            # got woken up due to event
+            self.worker_event.clear()
+            return True
+        except asyncio.TimeoutError:
+            return False
+
     async def _timer_worker(self):
         while True:
-            if len(self.timers) == 0:
-                # Nothing to do
-                await self.worker_event.wait()
-                if self.timer_debug:
-                    print("_timer_worker: event 0")
-                self.worker_event.clear()
-                continue
-            cur_nearest = self.timers[0][0]
-            wait_time = cur_nearest - time.ticks_ms()
-            if wait_time > 0:
-                if self.timer_debug:
-                    print(f"_timer_worker: next is {self.timers[0]}, sleep {wait_time} ms")
-                try:
-                    await asyncio.wait_for_ms(self.worker_event.wait(), wait_time)
-                    if self.timer_debug:
-                        print("_timer_worker: event 1")
-                    # got woken up due to event
-                    self.worker_event.clear()
-                    continue
-                except asyncio.TimeoutError:
-                    pass
+            next_timeout = self._next_timeout()
+            if next_timeout is None or next_timeout > 0:
+                await self._wait(next_timeout)
             else:
                 _, callback = heapq.heappop(self.timers)
                 safe_callback(callback, "timer callback")

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.route('/')
@@ -52,10 +61,14 @@ async def config_get(request):
 
 @webapp.route('/api/v1/config', methods=['PUT'])
 async def config_put(request):
-    if app.is_playing():
-        return 503
     try:
         config.set_config(request.json)
     except ValueError as ex:
         return str(ex), 400
     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}