Improvements to simplified demos (#44)

* enhance documentation; remove remaining anonymous callables; better variable names

* finish docstring

src/tqdm_publisher/_demos/_multiple_bars/_server.py

@@ -11,46 +11,56 @@
 async def handler(websocket: websockets.WebSocketServerProtocol) -> None:
     """Handle messages from the client and manage the client connections."""
 
-    class WebSocketProgressBar(threading.Thread):
+    class WebSocketProgressBar:
+        """
+        This is similar to the `send_progress_update_to_client` function from the single bar demo server.
+
+        The translation of this approach into a scoped class definition is merely to showcase an alternative approach
+        of the execution.
+        """
 
         def __init__(self, request_id: str):
             super().__init__()
             self.request_id = request_id
 
-        def update(self, format_dict) -> None:
+        def update(self, format_dict: dict) -> None:
             """
             This is the function that will run on every update of the TQDM object.
 
             It will forward the progress to the client.
             """
             asyncio.run(
-                websocket.send(message=json.dumps(obj=dict(request_id=self.request_id, format_dict=format_dict)))
+                websocket.send(message=json.dumps(obj=dict(format_dict=format_dict, request_id=self.request_id)))
             )
 
         def run(self):
             """
             Emulate running the specified number of tasks by sleeping the specified amount of time on each iteration.
 
-            Defaults are chosen for a deterministic and regular update period of one second for a total time of one minute.
+            Defaults are chosen for a deterministic and regular update period of one second for a total time of
+            seconds per bar.
+
+            This is similar to the `start_progress_bar` function from the single bar demo server. This is simply a
+            showcase of an alternative approach to defining and scoping the execution.
             """
             all_task_durations_in_seconds = [1.0 for _ in range(10)]  # Ten seconds at one task per second
-            progress_bar = self.progress_bar = tqdm_publisher.TQDMPublisher(iterable=all_task_durations_in_seconds)
-            progress_bar.subscribe(callback=self.update)
+            self.progress_bar = tqdm_publisher.TQDMPublisher(iterable=all_task_durations_in_seconds)
+            self.progress_bar.subscribe(callback=self.update)
 
-            for task_duration in progress_bar:
+            for task_duration in self.progress_bar:
                 time.sleep(task_duration)
 
-        # def start(self):
-        #     thread = threading.Thread(target=self.run_progress_bar)
-        #     thread.start()
+        def start(self):
+            thread = threading.Thread(target=self.run)
+            thread.start()
 
     # Wait for messages from the client
     async for message in websocket:
         message_from_client = json.loads(message)
 
         if message_from_client["command"] == "start":
-            progress_bar = WebSocketProgressBar(request_id=message_from_client["request_id"])
-            progress_bar.start()
+            web_socket_progress_bar = WebSocketProgressBar(request_id=message_from_client["request_id"])
+            web_socket_progress_bar.start()
 
 
 async def spawn_server() -> None:

src/tqdm_publisher/_demos/_single_bar/_server.py

@@ -12,7 +12,7 @@ def start_progress_bar(*, progress_callback: callable) -> None:
     """
     Emulate running the specified number of tasks by sleeping the specified amount of time on each iteration.
 
-    Defaults are chosen for a deterministic and regular update period of one second for a total time of one minute.
+    Defaults are chosen for a deterministic and regular update period of one second for a total time of 10 seconds.
     """
     all_task_durations_in_seconds = [1.0 for _ in range(10)]  # Ten seconds at one second per task
     progress_bar = tqdm_publisher.TQDMPublisher(iterable=all_task_durations_in_seconds)
@@ -29,42 +29,34 @@ def run_function_on_progress_update(format_dict: dict) -> None:
 
         This specifically requires the `id` of the progress bar and the `format_dict` of the TQDM instance.
         """
-        progress_callback(id=progress_bar.id, format_dict=format_dict)
+        progress_callback(format_dict=format_dict, progress_bar_id=progress_bar.id)
 
     progress_bar.subscribe(callback=run_function_on_progress_update)
 
     for task_duration in progress_bar:
         time.sleep(task_duration)
 
 
-def send_message_to_client(*, websocket: websockets.WebSocketServerProtocol, message: dict) -> None:
-    """
-    Send a message to a specific client.
-
-    This expects a WebSocket connection and a message (dict) to send.
-    """
-
-    asyncio.run(websocket.send(message=json.dumps(obj=message)))
-
-
 async def handler(websocket: websockets.WebSocketServerProtocol) -> None:
     """Handle messages from the client and manage the client connections."""
 
+    def send_progress_update_to_client(*, format_dict: dict, progress_bar_id: str) -> None:
+        """
+        This is the callback that actually sends the updated `format_dict` to the front end webpage.
+
+        It must be defined within the scope of the handler so that the `websocket` is inherited from the higher level.
+        """
+        message = json.dumps(obj=dict(format_dict=format_dict, progress_bar_id=progress_bar_id))
+        asyncio.run(websocket.send(message=message))
+
     # Wait for messages from the client
     async for message in websocket:
         message_from_client = json.loads(message)
 
         if message_from_client["command"] == "start":
-
             # Start the progress bar in a separate thread
             thread = threading.Thread(
-                target=start_progress_bar,
-                # On each update of the progress bar, send this update to the requesting client
-                kwargs=dict(
-                    progress_callback=lambda id, format_dict: send_message_to_client(
-                        websocket=websocket, message=dict(id=id, format_dict=format_dict)
-                    )
-                ),
+                target=start_progress_bar, kwargs=dict(progress_callback=send_progress_update_to_client)
             )
             thread.start()
 

src/tqdm_publisher/_publisher.py

@@ -8,7 +8,7 @@ class TQDMPublisher(base_tqdm):
     def __init__(self, *args, **kwargs):
         super().__init__(*args, **kwargs)
         self.id = str(uuid4())
-        self.callbacks = {}
+        self.callbacks = dict()
 
     # Override the update method to run callbacks
     def update(self, n: int = 1) -> Union[bool, None]: