[BUG] WebSocket framereceived event data type is incorrect

[themaxdavitt]

Context:

• Playwright Version: 1.32.1
• Operating System: Linux
• Python version: 3.11
• Browser: Chromium

WebSocket's framereceived event data is either a str or bytes, but the docs suggest it's a dict with property payload that's either a str or bytes. I think the relevant code is here:

playwright-python/playwright/_impl/_network.py

Lines 631 to 635 in 56a40a5

	def _on_frame_received(self, opcode: int, data: str) -> None:
	if opcode == 2:
	self.emit(WebSocket.Events.FrameReceived, base64.b64decode(data))
	elif opcode == 1:
	self.emit(WebSocket.Events.FrameReceived, data)

Here's a proof-of-concept demonstrating this inconsistency:

Proof-of-concept

from anyio import create_memory_object_stream, run
import math
from playwright.async_api import async_playwright


async def events(browser):
    context = await browser.new_context()
    page = await context.new_page()
    try:
        await page.goto("https://www.phoenixframework.org", wait_until="commit")
        send_stream, receive_stream = create_memory_object_stream(
            max_buffer_size=math.inf
        )
        page.on(
            "websocket",
            lambda websocket: websocket.on(
                "framereceived", lambda frame: send_stream.send_nowait(frame)
            ),
        )
        async with receive_stream:
            async for frame in receive_stream:
                # ignoring the case where `frame` is `bytes`, according to
                # the docs, this assert should fail
                assert isinstance(frame, str)
                yield frame
    finally:
        await context.close()


async def main():
    async with async_playwright() as playwright:
        browser = await playwright.chromium.launch()
        async for event in events(browser):
            print(event)


run(main)

Please let me know if you have any questions!

[mxschmitt]

Changing it from the code side would be a breaking change, so we can only adjust the docs.

I created a patch for it here: microsoft/playwright#22155