尝试在 JupyterLabs 中使用 Playwright - 未实现

Question

一直试图让 Playwright 在 Windows 的 Jupyter 实验室工作...Jupyter Labs 3.5.2、Python 3.9.15、Playwright 1.29.0。 代码是...

import asyncio

from playwright.async_api import async_playwright

async def main():
    async with async_playwright() as p:
        browser = await p.chromium.launch()
        page = await browser.new_page()
        await page.goto("http://playwright.dev")
        print(await page.title())
        await browser.close()
        
await main()

错误是：

Task exception was never retrieved
future: <Task finished name='Task-5' coro=<Connection.run() done, defined at C:\Users\Larry\anaconda3\envs\TDA_virtual\lib\site-packages\playwright\_impl\_connection.py:240> exception=NotImplementedError()>
Traceback (most recent call last):
  File "C:\Users\Larry\anaconda3\envs\TDA_virtual\lib\site-packages\playwright\_impl\_connection.py", line 247, in run
    await self._transport.connect()
  File "C:\Users\Larry\anaconda3\envs\TDA_virtual\lib\site-packages\playwright\_impl\_transport.py", line 132, in connect
    raise exc
  File "C:\Users\Larry\anaconda3\envs\TDA_virtual\lib\site-packages\playwright\_impl\_transport.py", line 120, in connect
    self._proc = await asyncio.create_subprocess_exec(
  File "C:\Users\Larry\anaconda3\envs\TDA_virtual\lib\asyncio\subprocess.py", line 236, in create_subprocess_exec
    transport, protocol = await loop.subprocess_exec(
  File "C:\Users\Larry\anaconda3\envs\TDA_virtual\lib\asyncio\base_events.py", line 1676, in subprocess_exec
    transport = await self._make_subprocess_transport(
  File "C:\Users\Larry\anaconda3\envs\TDA_virtual\lib\asyncio\base_events.py", line 498, in _make_subprocess_transport
    raise NotImplementedError
NotImplementedError
---------------------------------------------------------------------------
NotImplementedError                       Traceback (most recent call last)
Cell In[1], line 16
     13         print(await page.title())
     14         await browser.close()
---> 16 await main()

Cell In[1], line 9, in main()
      8 async def main():
----> 9     async with async_playwright() as p:
     10         browser = await p.chromium.launch()
     11         page = await browser.new_page()

File ~\anaconda3\envs\TDA_virtual\lib\site-packages\playwright\async_api\_context_manager.py:46, in PlaywrightContextManager.__aenter__(self)
     44 if not playwright_future.done():
     45     playwright_future.cancel()
---> 46 playwright = AsyncPlaywright(next(iter(done)).result())
     47 playwright.stop = self.__aexit__  # type: ignore
     48 return playwright

File ~\anaconda3\envs\TDA_virtual\lib\site-packages\playwright\_impl\_connection.py:247, in Connection.run(self)
    244 async def init() -> None:
    245     self.playwright_future.set_result(await self._root_object.initialize())
--> 247 await self._transport.connect()
    248 self._init_task = self._loop.create_task(init())
    249 await self._transport.run()

File ~\anaconda3\envs\TDA_virtual\lib\site-packages\playwright\_impl\_transport.py:132, in PipeTransport.connect(self)
    130 except Exception as exc:
    131     self.on_error_future.set_exception(exc)
--> 132     raise exc
    134 self._output = self._proc.stdin

File ~\anaconda3\envs\TDA_virtual\lib\site-packages\playwright\_impl\_transport.py:120, in PipeTransport.connect(self)
    117     if getattr(sys, "frozen", False):
    118         env.setdefault("PLAYWRIGHT_BROWSERS_PATH", "0")
--> 120     self._proc = await asyncio.create_subprocess_exec(
    121         str(self._driver_executable),
    122         "run-driver",
    123         stdin=asyncio.subprocess.PIPE,
    124         stdout=asyncio.subprocess.PIPE,
    125         stderr=_get_stderr_fileno(),
    126         limit=32768,
    127         creationflags=creationflags,
    128         env=env,
    129     )
    130 except Exception as exc:
    131     self.on_error_future.set_exception(exc)

File ~\anaconda3\envs\TDA_virtual\lib\asyncio\subprocess.py:236, in create_subprocess_exec(program, stdin, stdout, stderr, loop, limit, *args, **kwds)
    229     warnings.warn("The loop argument is deprecated since Python 3.8 "
    230                   "and scheduled for removal in Python 3.10.",
    231                   DeprecationWarning,
    232                   stacklevel=2
    233     )
    234 protocol_factory = lambda: SubprocessStreamProtocol(limit=limit,
    235                                                     loop=loop)
--> 236 transport, protocol = await loop.subprocess_exec(
    237     protocol_factory,
    238     program, *args,
    239     stdin=stdin, stdout=stdout,
    240     stderr=stderr, **kwds)
    241 return Process(transport, protocol, loop)

File ~\anaconda3\envs\TDA_virtual\lib\asyncio\base_events.py:1676, in BaseEventLoop.subprocess_exec(self, protocol_factory, program, stdin, stdout, stderr, universal_newlines, shell, bufsize, encoding, errors, text, *args, **kwargs)
   1674     debug_log = f'execute program {program!r}'
   1675     self._log_subprocess(debug_log, stdin, stdout, stderr)
-> 1676 transport = await self._make_subprocess_transport(
   1677     protocol, popen_args, False, stdin, stdout, stderr,
   1678     bufsize, **kwargs)
   1679 if self._debug and debug_log is not None:
   1680     logger.info('%s: %r', debug_log, transport)

File ~\anaconda3\envs\TDA_virtual\lib\asyncio\base_events.py:498, in BaseEventLoop._make_subprocess_transport(self, protocol, args, shell, stdin, stdout, stderr, bufsize, extra, **kwargs)
    494 async def _make_subprocess_transport(self, protocol, args, shell,
    495                                      stdin, stdout, stderr, bufsize,
    496                                      extra=None, **kwargs):
    497     """Create subprocess transport."""
--> 498     raise NotImplementedError

NotImplementedError: 

已经尝试了我发现的所有内容，包括使用以下每个注释行修改 Asyncio 的init .py：

import asyncio

if sys.platform == 'win32':
    from .windows_events import *
#    asyncio.set_event_loop_policy(asyncio.WindowsSelectorEventLoopPolicy())
#    asyncio.set_event_loop_policy(asyncio.WindowsProactorEventLoopPolicy())
    __all__ += windows_events.__all__
else:
    from .unix_events import *  # pragma: no cover
    __all__ += unix_events.__all__

到目前为止没有喜悦......任何人的帮助将不胜感激。

我相信错误来自 Playwright _transport.py 例程中的以下片段

 try:
            # For pyinstaller
            env = get_driver_env()
            if getattr(sys, "frozen", False):
                env.setdefault("PLAYWRIGHT_BROWSERS_PATH", "0")

            self._proc = await asyncio.create_subprocess_exec(
                str(self._driver_executable),
                "run-driver",
                stdin=asyncio.subprocess.PIPE,
                stdout=asyncio.subprocess.PIPE,
                stderr=_get_stderr_fileno(),
                limit=32768,
                creationflags=creationflags,
                env=env,
            )
        except Exception as exc:
            self.on_error_future.set_exception(exc)
            raise exc

我在想 JupyterLabs 的 IOLoop 是 selectoreventlooppolicy 并且不支持管道，也许这就是“未实现”的意思，但我仍在深入研究它是否属实以及是否可以修改行为.

再次感谢所有输入。

Answer 1

该问题似乎特定于 Windows 平台，并且在原始问题中确定为在 JupyterLabs 中使用 SelectorEventLoopPolicy 而不是 ProactorEventloopPolicy 是问题的根源。

由于 SelectorEventLoopPolicy 不支持 Pipes，当 Playwright 第一次尝试打开一个 pipe 时，会出现 Not implemented 错误。这个链接标识了 JupyterLab 的 EventLoopPolicy 是在 ipykernel 的例程 kernelapp.py 中设置的。

        if sys.platform.startswith("win") and sys.version_info >= (3, 8):
            import asyncio

            try:
                from asyncio import (
                    WindowsProactorEventLoopPolicy,
                    WindowsSelectorEventLoopPolicy,
                )
            except ImportError:
                pass
                # not affected
            else:
                if type(asyncio.get_event_loop_policy()) is WindowsProactorEventLoopPolicy:
                    # WindowsProactorEventLoopPolicy is not compatible with tornado 6
                    # fallback to the pre-3.8 default of Selector
#Comment out  - 637              asyncio.set_event_loop_policy(WindowsSelectorEventLoopPolicy())
#Add this to complete the if     print(f'do not change to Selector Event Loop')

不确定这是否会对其他操作产生任何不利影响，但它确实会导致原始代码在 JupyterLab 中执行。

我将其实现为单独的环境以防它有副作用。 也许负责 JupyterLab 的人可以评论可能的副作用。