Merge pull request #35 from Hundemeier/feature/remove_listener

added remove_listener function as described in #34

README.md

@@ -182,6 +182,9 @@ Functions:
    You can also use the decorator `@listen_on('universe', universe=<universe>)`.
    The callback should have one argument: `callback(packet)`
      * `packet: DataPacket`: the received DataPacket with all information
+ * `remove_listener(<callback>)`: removes a previously registered listener regardless of the trigger.
+ This means a listener can only be removed completely, even if it was listening to multiple universes.
+ If the function never was registered, nothing happens. Note: if a function was registered multiple times, this remove function needs to be called only once.
 
 ### DataPacket
 This is an abstract representation of an sACN Data packet that carries the DMX data. This class is used internally by

sacn/receiver.py

@@ -77,6 +77,20 @@ def register_listener(self, trigger: str, func: callable, **kwargs) -> None:
         else:
             raise TypeError(f'The given trigger "{trigger}" is not a valid one!')
 
+    def remove_listener(self, func: callable) -> None:
+        """
+        Removes the given function from all listening options (see LISTEN_ON_OPTIONS).
+        If the function never was registered, nothing happens. Note: if a function was registered multiple times,
+        this remove function needs to be called only once.
+        :param func: the callback
+        """
+        for _trigger, listeners in self._callbacks.items():
+            while True:
+                try:
+                    listeners.remove(func)
+                except ValueError:
+                    break
+
     def join_multicast(self, universe: int) -> None:
         """
         Joins the multicast address that is used for the given universe. Note: If you are on Windows you must have given

sacn/receiver_test.py

@@ -64,6 +64,40 @@ def callback_packet(packet):
     assert called
 
 
+def test_remove_listener():
+    receiver, socket = get_receiver()
+
+    packetSend = DataPacket(
+        cid=tuple(range(0, 16)),
+        sourceName='Test',
+        universe=1,
+        dmxData=tuple(range(0, 16))
+    )
+
+    called = 0
+
+    def callback_packet(packet):
+        assert packetSend.__dict__ == packet.__dict__
+        nonlocal called
+        called += 1
+
+    # register listener multiple times
+    receiver.register_listener('universe', callback_packet, universe=packetSend.universe)
+    receiver.register_listener('universe', callback_packet, universe=packetSend.universe)
+
+    socket.call_on_data(bytes(packetSend.getBytes()), 0)
+    assert called == 2
+
+    # change DMX data to trigger a change
+    packetSend.dmxData = tuple(range(16, 32))
+    packetSend.sequence_increase()
+
+    receiver.remove_listener(callback_packet)
+
+    socket.call_on_data(bytes(packetSend.getBytes()), 0)
+    assert called == 2
+
+
 def test_invalid_listener():
     receiver, socket = get_receiver()