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入门指南 - 库

安装​

Pip​

PyPI version

pip install --upgrade pip
pip install playwright
playwright install

Conda​

Anaconda version

conda config --add channels conda-forge
conda config --add channels microsoft
conda install playwright
playwright install

这些命令会下载Playwright包并安装Chromium、Firefox和WebKit的浏览器二进制文件。要修改此行为，请参阅installation parameters。

使用方法​

安装完成后，您可以在Python脚本中import Playwright，并启动3种浏览器中的任意一种（chromium、firefox和webkit）。

from playwright.sync_api import sync_playwright

with sync_playwright() as p:
    browser = p.chromium.launch()
    page = browser.new_page()
    page.goto("http://playwright.dev")
    print(page.title())
    browser.close()

Playwright 支持两种API变体：同步和异步。如果您的现代项目使用asyncio，则应使用异步API：

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()

asyncio.run(main())

第一个脚本​

在我们的第一个脚本中，我们将导航到https://playwright.dev/并在WebKit中截取屏幕截图。

from playwright.sync_api import sync_playwright

with sync_playwright() as p:
    browser = p.webkit.launch()
    page = browser.new_page()
    page.goto("https://playwright.dev/")
    page.screenshot(path="example.png")
    browser.close()

默认情况下，Playwright以无头模式运行浏览器。要查看浏览器界面，请将headless选项设置为False。您还可以使用slow_mo来减慢执行速度。在调试工具section中了解更多信息。

firefox.launch(headless=False, slow_mo=50)

交互式模式 (REPL)​

您可以启动交互式python REPL：

python

然后在其内部启动Playwright以进行快速实验：

from playwright.sync_api import sync_playwright
playwright = sync_playwright().start()
# Use playwright.chromium, playwright.firefox or playwright.webkit
# Pass headless=False to launch() to see the browser UI
browser = playwright.chromium.launch()
page = browser.new_page()
page.goto("https://playwright.dev/")
page.screenshot(path="example.png")
browser.close()
playwright.stop()

异步REPL例如asyncio REPL:

python -m asyncio
from playwright.async_api import async_playwright
playwright = await async_playwright().start()
browser = await playwright.chromium.launch()
page = await browser.new_page()
await page.goto("https://playwright.dev/")
await page.screenshot(path="example.png")
await browser.close()
await playwright.stop()

Pyinstaller​

你可以使用Playwright与Pyinstaller来创建独立的可执行文件。

main.py
from playwright.sync_api import sync_playwright

with sync_playwright() as p:
    browser = p.chromium.launch()
    page = browser.new_page()
    page.goto("https://playwright.dev/")
    page.screenshot(path="example.png")
    browser.close()

如果您想将浏览器与可执行文件捆绑在一起：

PLAYWRIGHT_BROWSERS_PATH=0 playwright install chromium
pyinstaller -F main.py
note

将浏览器与可执行文件捆绑会生成更大的二进制文件。建议仅捆绑您使用的浏览器。

已知问题​

time.sleep() 会导致状态过时​

大多数情况下您不需要手动等待，因为Playwright具备自动等待功能。如果您仍然依赖手动等待，应该使用page.wait_for_timeout(5000)而非time.sleep(5)，而且最好完全避免使用超时等待，但有时这对调试很有帮助。在这些情况下，请使用我们的等待方法(wait_for_timeout)替代time模块。这是因为我们在内部依赖异步操作，当使用time.sleep(5)时这些操作无法被正确处理。

在Windows上与asyncio的SelectorEventLoop不兼容​

Playwright在子进程中运行驱动程序，因此在Windows上需要使用asyncio的ProactorEventLoop，因为SelectorEventLoop不支持异步子进程。

在Windows Python 3.7上，Playwright将默认事件循环设置为ProactorEventLoop，因为这是Python 3.8+的默认设置。

多线程​

Playwright的API不是线程安全的。如果您在多线程环境中使用Playwright，应该为每个线程创建一个playwright实例。详情请参阅线程问题。