Puppeteer

API | FAQ | Contributing

Puppeteer is a Node library which provides a high-level API to control headless Chrome or Chromium over the DevTools Protocol. It can also be configured to use full (non-headless) Chrome or Chromium.

What can I do?

Most things that you can do manually in the browser can be done using Puppeteer! Here are a few examples to get you started:

Generate screenshots and PDFs of pages.
Crawl a SPA and generate pre-rendered content (i.e. "SSR").
Scrape content from websites.
Automate form submission, UI testing, keyboard input, etc.
Create an up-to-date, automated testing environment. Run your tests directly in the latest version of Chrome using the latest JavaScript and browser features.
Capture a timeline trace of your site to help diagnose performance issues.

Give it a spin: https://try-puppeteer.appspot.com/

Getting Started

Installation

To use Puppeteer in your project, run:

yarn add puppeteer
# or "npm i puppeteer"

Note: When you install Puppeteer, it downloads a recent version of Chromium (~71Mb Mac, ~90Mb Linux, ~110Mb Win) that is guaranteed to work with the API. To skip the download, see Environment variables.

Usage

Caution: Puppeteer requires at least Node v6.4.0, but the examples below use async/await which is only supported in Node v7.6.0 or greater.

Puppeteer will be familiar to people using other browser testing frameworks. You create an instance of Browser, open pages, and then manipulate them with Puppeteer's API.

Example - navigating to https://example.com and saving a screenshot as example.png:

const puppeteer = require('puppeteer');

(async () => {
  const browser = await puppeteer.launch();
  const page = await browser.newPage();
  await page.goto('https://example.com');
  await page.screenshot({path: 'example.png'});

  await browser.close();
})();

Puppeteer sets an initial page size to 800px x 600px, which defines the screenshot size. The page size can be customized with Page.setViewport().

Example - create a PDF.

const puppeteer = require('puppeteer');

(async () => {
  const browser = await puppeteer.launch();
  const page = await browser.newPage();
  await page.goto('https://news.ycombinator.com', {waitUntil: 'networkidle2'});
  await page.pdf({path: 'hn.pdf', format: 'A4'});

  await browser.close();
})();

See Page.pdf() for more information about creating pdfs.

Example - evaluate script in the context of the page

const puppeteer = require('puppeteer');

(async () => {
  const browser = await puppeteer.launch();
  const page = await browser.newPage();
  await page.goto('https://example.com');

  // Get the "viewport" of the page, as reported by the page.
  const dimensions = await page.evaluate(() => {
    return {
      width: document.documentElement.clientWidth,
      height: document.documentElement.clientHeight,
      deviceScaleFactor: window.devicePixelRatio
    };
  });

  console.log('Dimensions:', dimensions);

  await browser.close();
})();

See Page.evaluate() for more information on evaluate and related methods like evaluateOnNewDocument and exposeFunction.

Default runtime settings

1. Uses Headless mode

Puppeteer launches Chromium in headless mode. To launch a full version of Chromium, set the 'headless' option when launching a browser:

const browser = await puppeteer.launch({headless: false}); // default is true

2. Runs a bundled version of Chromium

By default, Puppeteer downloads and uses a specific version of Chromium so its API is guaranteed to work out of the box. To use Puppeteer with a different version of Chrome or Chromium, pass in the executable's path when creating a Browser instance:

const browser = await puppeteer.launch({executablePath: '/path/to/Chrome'});

See Puppeteer.launch() for more information.

See this article for a description of the differences between Chromium and Chrome. This article describes some differences for Linux users.

3. Creates a fresh user profile

Puppeteer creates its own Chromium user profile which it cleans up on every run.

API Documentation

Explore the API documentation and examples to learn more.

Debugging tips

Turn off headless mode - sometimes it's useful to see what the browser is displaying. Instead of launching in headless mode, launch a full version of the browser using headless: false:
```
 const browser = await puppeteer.launch({headless: false});
```
Slow it down - the slowMo option slows down Puppeteer operations by the specified amount of milliseconds. It's another way to help see what's going on.
```
 const browser = await puppeteer.launch({
   headless: false,
   slowMo: 250 // slow down by 250ms
 });
```

Capture console output - You can listen for the console event. This is also handy when debugging code in page.evaluate():

 page.on('console', msg => console.log('PAGE LOG:', ...msg.args));
 
 await page.evaluate(() => console.log(`url is ${location.href}`));

Enable verbose logging - All public API calls and internal protocol traffic will be logged via the debug module under the puppeteer namespace.

 # Basic verbose logging
 env DEBUG="puppeteer:*" node script.js

 # Debug output can be enabled/disabled by namespace
 env DEBUG="puppeteer:*,-puppeteer:protocol" node script.js # everything BUT protocol messages
 env DEBUG="puppeteer:session" node script.js # protocol session messages (protocol messages to targets)
 env DEBUG="puppeteer:mouse,puppeteer:keyboard" node script.js # only Mouse and Keyboard API calls

 # Protocol traffic can be rather noisy. This example filters out all Network domain messages
 env DEBUG="puppeteer:*" env DEBUG_COLORS=true node script.js 2>&1 | grep -v '"Network'

Contributing to Puppeteer

Check out contributing guide to get an overview of Puppeteer development.

FAQ

Q: Which Chromium version does Puppeteer use?

Look for chromium_revision in package.json.

Puppeteer bundles Chromium to ensure that the latest features it uses are guaranteed to be available. As the DevTools protocol and browser improve over time, Puppeteer will be updated to depend on newer versions of Chromium.

Q: What is the difference between Puppeteer, Selenium / WebDriver, and PhantomJS?

Selenium / WebDriver is a well-established cross-browser API that is useful for testing cross-browser support.

Puppeteer works only with Chromium or Chrome. However, many teams only run unit tests with a single browser (e.g. PhantomJS). In non-testing use cases, Puppeteer provides a powerful but simple API because it's only targeting one browser that enables you to rapidly develop automation scripts.

Puppeteer bundles the latest versions of Chromium.

Q: Who maintains Puppeteer?

The Chrome DevTools team maintains the library, but we'd love your help and expertise on the project! See Contributing.

Q: Why is the Chrome team building Puppeteer?

The goals of the project are simple:

Q: How does Puppeteer compare with other headless Chrome projects?

The past few months have brought several new libraries for automating headless Chrome. As the team authoring the underlying DevTools Protocol, we're excited to witness and support this flourishing ecosystem.

We've reached out to a number of these projects to see if there are opportunities for collaboration, and we're happy to do what we can to help.

Q: What features does Puppeteer not support?

You may find that Puppeteer does not behave as expected when controlling pages that incorporate audio and video. (For example, video playback/screenshots is likely to fail.) There are two reasons for this:

Puppeteer is bundled with Chromium--not Chrome--and so by default, it inherits all of Chromium's media-related limitations. This means that Puppeteer does not support licensed formats such as AAC or H.264. (However, it is possible to force Puppeteer to use a separately-installed version Chrome instead of Chromium via the executablePath option to puppeteer.launch. You should only use this configuration if you need an official release of Chrome that supports these media formats.)
Since Puppeteer (in all configurations) controls a desktop version of Chromium/Chrome, features that are only supported by the mobile version of Chrome are not supported. This means that Puppeteer does not support HTTP Live Streaming (HLS).

License

a1xon/puppeteer

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