WebSocket Fails with HTTPS Enabled: OSError -30464 in adafruit_httpserver

[berkut0]

CircuitPython version and board name

Adafruit CircuitPython 9.2.4 on 2025-01-29; Wemos Lolin C3 Mini with ESP32-C3FH4

Code/REPL

import wifi
import socketpool
import asyncio
from adafruit_httpserver import Server, Request, Response, Websocket, GET

pool = socketpool.SocketPool(wifi.radio)

server = Server(
    pool,
#     root_path="/static",
    https=True,
    certfile="cert.pem",
    keyfile="key.pem",
    debug=True)

websocket: Websocket = None

@server.route("/ws", GET)
def connect_client(request: Request):
    global websocket  # pylint: disable=global-statement
    if websocket is not None:
        websocket.close()  # Close any existing connection
    websocket = Websocket(request)
    return websocket

async def handle_http_requests():
    while True:
        server.poll()
        await asyncio.sleep_ms(0)

async def handle_websocket_requests():
    while True:
        if websocket is not None:
            if (data := websocket.receive(fail_silently=True)) is not None:
                print(data)
        await asyncio.sleep_ms(0)

async def send_websocket_messages():
    while True:
        if websocket is not None:
            websocket.send_message("aaaa", fail_silently=True)
        await asyncio.sleep_ms(1000)

server.start(str(wifi.radio.ipv4_address))

async def main():
    await asyncio.gather(
        asyncio.create_task(handle_websocket_requests()),
        asyncio.create_task(send_websocket_messages()),
        asyncio.create_task(handle_http_requests())
        )

asyncio.run(main())

Behavior

When HTTPS is enabled (by providing certificate and key files), static content is served correctly; however, WebSocket connections fail. Testing with a C# Watson WebSocket client produces the error:

Traceback (most recent call last):
  File "adafruit_httpserver/server.py", line 476, in poll
OSError: -30464
Traceback (most recent call last):
  File "code.py", line 101, in <module>
  File "asyncio/core.py", line 317, in run
  File "asyncio/core.py", line 276, in run_until_complete
  File "asyncio/core.py", line 261, in run_until_complete
  File "code.py", line 98, in main
  File "asyncio/funcs.py", line 162, in gather
  File "asyncio/core.py", line 261, in run_until_complete
  File "code.py", line 39, in handle_http_requests
  File "adafruit_httpserver/server.py", line 528, in poll
  File "adafruit_httpserver/server.py", line 476, in poll
OSError: -30464

This issue disappears when HTTPS is disabled (i.e., when the certificate-related parameters are commented out).

   server = Server(
       pool,
       # https=True,
       # certfile="cert.pem",
       # keyfile="key.pem",
       debug=True)

Expected Behavior:
WebSocket connections should be established successfully regardless of whether HTTPS is enabled, while still serving static content securely.

Actual Behavior:
With HTTPS enabled, WebSocket connections fail with the error OSError: -30464 during the polling process.

Additional Context:

• The issue appears to be isolated to WebSocket functionality when using HTTPS.
• The rest of the HTTP functionality (e.g., serving static content) is unaffected.
• This behavior was reproduced on a CircuitPython environment using the adafruit_httpserver library.