ring04h/pyppeteer: Headless chrome/chromium automation library (unofficial port of puppeteer)
2018-05-26 00:13:07 Author: github.com(查看原文) 阅读量:123 收藏

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Unofficial Python port of puppeteer JavaScript (headless) chrome/chromium browser automation library.

Note: Currently not all features are tested and some APIs are unstable

Installation

Pyppeteer requires python 3.6+. (experimentally supports python 3.5)

Install by pip from PyPI:

python3 -m pip install pyppeteer

Or install latest version from github:

python3 -m pip install -U git+https://github.com/miyakogi/pyppeteer.git@dev

Usage

Note: When you run pyppeteer first time, it downloads a recent version of Chromium (~100MB).

Example: open web page and take a screenshot.

import asyncio
from pyppeteer import launch

async def main():
    browser = await launch()
    page = await browser.newPage()
    await page.goto('http://example.com')
    await page.screenshot({'path': 'example.png'})
    await browser.close()

asyncio.get_event_loop().run_until_complete(main())

Example: evaluate script on the page.

import asyncio
from pyppeteer import launch

async def main():
    browser = await launch()
    page = await browser.newPage()
    await page.goto('http://example.com')
    await page.screenshot({'path': 'example.png'})

    dimensions = await page.evaluate('''() => {
        return {
            width: document.documentElement.clientWidth,
            height: document.documentElement.clientHeight,
            deviceScaleFactor: window.devicePixelRatio,
        }
    }''')

    print(dimensions)
    # >>> {'width': 800, 'height': 600, 'deviceScaleFactor': 1}
    await browser.close()

asyncio.get_event_loop().run_until_complete(main())

Pyppeteer has almost same API as puppeteer. More APIs are listed in the document.

Puppeteer's document is also useful for pyppeteer users.

Differences between puppeteer and pyppeteer

Pyppeteer is to be as similar as puppeteer, but some differences between python and JavaScript make it difficult.

These are differences between puppeteer and pyppeteer.

Keyword argument for options

Puppeteer uses object (dictionary in python) for passing options to functions/methods. Pyppeteer accepts both dictionary and keyword argument for options.

Dictionary style option (similar to puppeteer):

browser = await launch({'headless': True})

Keyword argument style option (more pythonic, isn't it?):

browser = await launch(headless=True)

Element selector method name ($ -> querySelector)

In python, $ is not usable for method name. So pyppeteer uses Page.querySelector() instead of Page.$(), and Page.querySelectorAll() instead of Page.$$(). Pyppeteer has shorthands for these methods, Page.J() and Page.JJ().

Argument of Page.evaluate() and Page.querySelectorEval()

Puppeteer's version of evaluate() takes JavaScript raw function or string of JavaScript expression, but pyppeteer takes string of JavaScript. JavaScript strings can be function or expression. Pyppeteer tries to automatically detect the string is function or expression, but sometimes fails. If expression string is treated as function, and raise error, add force_expr=True option, which force pyppeteer to treat the string as expression.

Example to get page content:

content = await page.evaluate('document.body.textContent', force_expr=True)

Example to get element's inner text:

element = await page.querySelector('h1')
title = await page.evaluate('(element) => element.textContent', element)

Future Plan

  1. Catch up development of puppeteer
    • Not intend to add original API which puppeteer does not have
  2. Add more tests and fix bugs

Credits

This package was created with Cookiecutter and the audreyr/cookiecutter-pypackage project template.


文章来源: https://github.com/ring04h/pyppeteer
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