如何在 Jupyter 笔记本中使用 Playwright 库而不是使用常规 .py 脚本（在 Windows 上）

Question

我想使用自动浏览器并使用 jupyter 笔记本单元而不是使用 .py 脚本执行我的步骤。这与名为 selenium 的浏览器自动化库配合得很好。

它不能与名为 Playwright 的库一起正常工作。事实上它根本不起作用。我尝试了他们在手册中提供的每一行代码。 jupyter 笔记本上什么都不起作用。只要将相同的代码复制粘贴到某个 .py 文件中并执行它，一切都可以在我的机器上正常运行。 我正在谈论的各种示例可以在这里找到：https://playwright.dev/python/docs/intro

我真的不明白为什么我无法让它在 jupyter 笔记本中工作，特别是如果它在几乎每个 .py 文件中都工作正常的话。

编辑：显然它可以在 Mac 上运行，但我使用 Windows

Answer 1

下面的代码适用于 MacOS 和 Linux。

---

如https://github.com/microsoft/playwright-python/issues/480

中所述

Jupyter Notebook 使用 asyncio 事件循环，因此您应该使用 async api。

from playwright.async_api import async_playwright

playwright = await async_playwright().start()
browser = await playwright.chromium.launch(headless = False)
page = await browser.new_page()

await page.goto("http://whatsmyuseragent.org/")

# await page.screenshot(path="example.png")
# await browser.close()
# await playwright.stop()

---

如果你使用

sync

API，它会抛出这样的错误：

from playwright.sync_api import sync_playwright
playwright = sync_playwright().start()

'''
Error: It looks like you are using Playwright Sync API inside the asyncio loop.
Please use the Async API instead.
'''

Answer 2

---

由于 Colab 笔记本是托管 Jupyter 笔记本，我建议使用以下解决方案在托管 Jupyter 实例中运行 playwright。

我只在我的 Google Colab 笔记本中进行了测试，尚未在本地托管的 Jupyter 实例中进行测试。

Google Colab 解决方案中的剧作家

Answer 3

如果您在 Windows 上的 Jupyter 笔记本中运行 Playwright 时遇到问题，请尝试禁用内核的事件循环策略。

1. 导航到 Python 目录中的 Lib/site-packages/ipykernel/kernelapp.py。
2. 禁用以下行：

   asyncio.set_event_loop_policy(WindowsSelectorEventLoopPolicy())

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
            # asyncio.set_event_loop_policy(WindowsSelectorEventLoopPolicy())
            pass

Answer 4

如果你无法在jupyter笔记本中使用async API，你可以尝试为playwright创建一个虚拟环境：

在终端：

# create a virtual environment for playwright
python3 -m venv playwright_new
source ~/playwright_new/bin/activate
pip install playwright ipykernel requests 
playwright install

然后，为jupyter笔记本创建内核链接：

source ~/playwright_new/bin/activate

# create kernel link for jupyter notebook 
python -m ipykernel install --user --name playwright_new --display-name "playwright_new"

# in mac
ls /Users/xxx/Library/Jupyter/kernels/
tree /Users/xxx/Library/Jupyter/kernels/playwright_new
    /Users/xxx/Library/Jupyter/kernels/playwright_new
    ├── kernel.json
    ├── logo-32x32.png
    └── logo-64x64.png

# or in linux
tree /root/.local/share/jupyter/kernels

然后，再次运行Python代码。

from playwright.async_api import async_playwright

playwright = await async_playwright().start()
browser = await playwright.chromium.launch(headless = False)
page = await browser.new_page()

await page.goto("http://whatsmyuseragent.org/")

---

错误调试

if exec python code throws an Error:

Error: Executable doesn't exist at /Users/xxxx/Library/Caches/ms-playwright/chromium-1000/chrome-mac/Chromium.app/Contents/MacOS/Chromium
╔═════════════════════════════════════════════════════════════════════════╗
║ Looks like Playwright Test or Playwright was just installed or updated. ║
║ Please run the following command to download new browsers:              ║
║                                                                         ║
║     playwright install                                                  ║
║                                                                         ║
║ <3 Playwright Team                                                      ║
╚═════════════════════════════════════════════════════════════════════════╝

在终端：

# you already install playwright
playwright install 

cd /Users/xxxx/Library/Caches/ms-playwright
ls
    chromium-978106/ ffmpeg-1007/     firefox-1319/    webkit-1616/

# but the folder ms-playwright/chromium-1000 NOT EXISTS
# COPY the exists chromium folder with a new name  `chromium-1000`
cp -r chromium-978106 chromium-1000