Modified Websocket example to use asyncio

michalpokusa · michalpokusa · commit b8a3561f23be · 2023-09-25T06:54:31.000Z
diff --git a/docs/examples.rst b/docs/examples.rst
@@ -315,12 +315,15 @@ the client and the server.
 Remember, that because Websockets also receive data, you have to explicitly call ``.receive()`` on the ``Websocket`` object to get the message.
 This is anologous to calling ``.poll()`` on the ``Server`` object.
 
+The following example uses ``asyncio``, which has to be installed separately. It is not necessary to use ``asyncio`` to use Websockets,
+but it is recommended as it makes it easier to handle multiple tasks. It can be used in any of the examples, but here it is particularly useful.
+
 **Because of the limited number of concurrently open sockets, it is not possible to process more than one Websocket response at the same time.
 This might change in the future, but for now, it is recommended to use Websocket only with one client at a time.**
 
 .. literalinclude:: ../examples/httpserver_websocket.py
     :caption: examples/httpserver_websocket.py
-    :emphasize-lines: 12,21,67-73,83,90
+    :emphasize-lines: 12,20,65-72,88,99
     :linenos:
 
 Multiple servers
diff --git a/examples/httpserver_sse.py b/examples/httpserver_sse.py
@@ -1,4 +1,4 @@
-# SPDX-FileCopyrightText: 2023 Dan Halbert for Adafruit Industries
+# SPDX-FileCopyrightText: 2023 Michał Pokusa
 #
 # SPDX-License-Identifier: Unlicense
 
diff --git a/examples/httpserver_websocket.py b/examples/httpserver_websocket.py
@@ -1,8 +1,8 @@
-# SPDX-FileCopyrightText: 2023 Dan Halbert for Adafruit Industries
+# SPDX-FileCopyrightText: 2023 Michał Pokusa
 #
 # SPDX-License-Identifier: Unlicense
 
-from time import monotonic
+from asyncio import create_task, gather, run, sleep as async_sleep
 import board
 import microcontroller
 import neopixel
@@ -17,9 +17,7 @@
 
 pixel = neopixel.NeoPixel(board.NEOPIXEL, 1)
 
-
 websocket: Websocket = None
-next_message_time = monotonic()
 
 HTML_TEMPLATE = """
 <html lang="en">
@@ -75,17 +73,40 @@ def connect_client(request: Request):
 
 
 server.start(str(wifi.radio.ipv4_address))
-while True:
-    server.poll()
 
-    # Check for incoming messages from client
-    if websocket is not None:
-        if (data := websocket.receive(True)) is not None:
-            r, g, b = int(data[1:3], 16), int(data[3:5], 16), int(data[5:7], 16)
-            pixel.fill((r, g, b))
-
-    # Send a message every second
-    if websocket is not None and next_message_time < monotonic():
-        cpu_temp = round(microcontroller.cpu.temperature, 2)
-        websocket.send_message(str(cpu_temp))
-        next_message_time = monotonic() + 1
+
+async def handle_http_requests():
+    while True:
+        server.poll()
+
+        await async_sleep(0)
+
+
+async def handle_websocket_requests():
+    while True:
+        if websocket is not None:
+            if (data := websocket.receive(fail_silently=True)) is not None:
+                r, g, b = int(data[1:3], 16), int(data[3:5], 16), int(data[5:7], 16)
+                pixel.fill((r, g, b))
+
+        await async_sleep(0)
+
+
+async def send_websocket_messages():
+    while True:
+        if websocket is not None:
+            cpu_temp = round(microcontroller.cpu.temperature, 2)
+            websocket.send_message(str(cpu_temp), fail_silently=True)
+
+        await async_sleep(1)
+
+
+async def main():
+    await gather(
+        create_task(handle_http_requests()),
+        create_task(handle_websocket_requests()),
+        create_task(send_websocket_messages()),
+    )
+
+
+run(main())

Original file line number	Diff line number	Diff line change
`@@ -1,4 +1,4 @@`
`1`		`-# SPDX-FileCopyrightText: 2023 Dan Halbert for Adafruit Industries`
	`1`	`+# SPDX-FileCopyrightText: 2023 Michał Pokusa`
`2`	`2`	`#`
`3`	`3`	`# SPDX-License-Identifier: Unlicense`
`4`	`4`