jdescottes-pptr-ff
Advanced tools
Puppeteer is a Node library which provides a high-level API to control Chrome or Chromium over the DevTools Protocol. Puppeteer runs headless by default, but can be configured to run full (non-headless) Chrome or Chromium.
Most things that you can do manually in the browser can be done using Puppeteer! Here are a few examples to get you started:
Give it a spin: https://try-puppeteer.appspot.com/
To use Puppeteer in your project, run:
npm i puppeteer
# or "yarn add puppeteer"
Note: When you install Puppeteer, it downloads a recent version of Chromium (~170Mb Mac, ~282Mb Linux, ~280Mb Win) that is guaranteed to work with the API. To skip the download, see Environment variables.
Note: 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:
Save file as example.js
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();
})();
Execute script on the command line
node example.js
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.
Save file as hn.js
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();
})();
Execute script on the command line
node hn.js
See Page.pdf() for more information about creating pdfs.
Example - evaluate script in the context of the page
Save file as get-dimensions.js
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();
})();
Execute script on the command line
node get-dimensions.js
See Page.evaluate() for more information on evaluate and related methods like evaluateOnNewDocument and exposeFunction.
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.
Explore the API documentation and examples to learn more.
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.text()));
await page.evaluate(() => console.log(`url is ${location.href}`));
Stop test execution and use a debugger in browser
Use {devtools: true} when launching Puppeteer:
const browser = await puppeteer.launch({devtools: true});
Change default test timeout:
jest: jest.setTimeout(100000);
jasmine: jasmine.DEFAULT_TIMEOUT_INTERVAL = 100000;
mocha: this.timeout(100000); (don't forget to change test to use function and not '=>')
Add an evaluate statement with debugger inside / add debugger to an existing evaluate statement:
await page.evaluate(() => {debugger;});
The test will now stop executing in the above evaluate statement, and chromium will stop in debug mode.
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'
Check out contributing guide to get an overview of Puppeteer development.
The Chrome DevTools team maintains the library, but we'd love your help and expertise on the project! See Contributing.
The goals of the project are:
We adapt Chromium principles to help us drive product decisions:
No. Both projects are valuable for very different reasons:
That said, you can use Puppeteer to run tests against Chromium, e.g. using the community-driven jest-puppeteer. While this probably shouldn’t be your only testing solution, it does have a few good points compared to WebDriver:
We see Puppeteer as an indivisible entity with Chromium. Each version of Puppeteer bundles a specific version of Chromium – the only version it is guaranteed to work with.
This is not an artificial constraint: A lot of work on Puppeteer is actually taking place in the Chromium repository. Here’s a typical story:
However, oftentimes it is desirable to use Puppeteer with the official Google Chrome rather than Chromium. For this to work, you should pick the version of Puppeteer that uses the Chromium version close enough to Chrome.
Look for chromium_revision in package.json.
From Puppeteer’s standpoint, “navigation” is anything that changes a page’s URL. Aside from regular navigation where the browser hits the network to fetch a new document from the web server, this includes anchor navigations and History API usage.
With this definition of “navigation,” Puppeteer works seamlessly with single-page applications.
In browsers, input events could be divided into two big groups: trusted vs. untrusted.
document.createEvent or element.click() methods.Websites can distinguish between these two groups:
Event.isTrusted event flag'click' event is preceded by 'mousedown' and 'mouseup' events.For automation purposes it’s important to generate trusted events. All input events generated with Puppeteer are trusted and fire proper accompanying events. If, for some reason, one needs an untrusted event, it’s always possible to hop into a page context with page.evaluate and generate a fake event:
await page.evaluate(() => {
document.querySelector('button[type=submit]').click();
});
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:
executablePath option to puppeteer.launch. You should only use this configuration if you need an official release of Chrome that supports these media formats.)We have a troubleshooting guide for various operating systems that lists the required dependencies.
You can check out this repo or install the latest prerelease from npm:
npm i --save puppeteer@next
Please note that prerelease may be unstable and contain bugs.
There are many ways to get help on Puppeteer:
Make sure to search these channels before posting your question.
FAQs
Experimental Puppeteer using official Firefox Nightlies
We found that jdescottes-pptr-ff demonstrated a not healthy version release cadence and project activity because the last version was released a year ago. It has 1 open source maintainer collaborating on the project.
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