[BUG] Websockets hang on recv()

[dleber]

Please check the following items and answer all the questions when reporting a bug,
otherwise it will be closed immediately.

• This is NOT a site-related "bugs", e.g. some site blocks me when using curl_cffi,
  UNLESS it has been verified that the reason is missing pieces in the impersonation.
• A code snippet that can reproduce this bug is provided, even if it's a one-liner.
• Version information will be pasted as below.

Describe the bug

Using websockets, when iterating through received messages, websockets hang on recv() most of the time. This occurs for both async and non-async implementations.

When running the code below, call either asyncio.run(ws_curl_cffi_async()) or ws_curl_cffi() multiple times to discover the issue, as occasionally it works as expected (usually on the first run).

The code also includes a snippet using Python's websocket-client library, which reliably works each time.

Separately, it would be great if a message timeout could be configured, such that recv() doesn't hang indefinitely.

To Reproduce

import asyncio

from curl_cffi.requests import AsyncSession, WebSocket

async def ws_curl_cffi_async():
    async with AsyncSession() as s:
        ws = await s.ws_connect("wss://echo.websocket.org")
        await asyncio.gather(*[ws.send_str(f"Hello {i}") for i in range(20)])
        async for message in ws:
            print(message)

def ws_curl_cffi():
    ws = WebSocket().connect("wss://echo.websocket.org")
    for i in range(20):
        ws.send(f"Hello {i}")
    for i in range(20):
        print(ws.recv())
    ws.close()


if __name__ == "__main__":
    # asyncio.run(ws_curl_cffi_async())
    ws_curl_cffi()

The example below uses the websocket-client library to demonstrate the expected behavior. It works reliably each time.

pip install websocket-client==1.6.4

from websocket import create_connection

def ws_websocket():
    ws = create_connection("wss://echo.websocket.org")
    for i in range(20):
        ws.send(f"Hello {i}")
    
    for i in range(20):
        print(ws.recv())

    ws.close()

if __name__ == "__main__":
    ws_websocket()

Expected behavior

All 19 messages should be received and printed.

Versions

• OS: Linux aarch64 (python:3.12.2 Docker image)
• curl-cffi==v0.8.1b9

Additional Information

This is possibly an issue related to queuing of response messages. If each message is read immediately after the send, it works more reliably, but this is only applicable to this "echo" example. For example

def ws_websocket():
    ws = create_connection("wss://echo.websocket.org")
    for i in range(20):
        ws.send(f"Hello {i}")
        print(ws.recv())

    ws.close()