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* chore(main): release 15.4.2 * chore: generate versioned docs Co-authored-by: release-please[bot] <55107282+release-please[bot]@users.noreply.github.com> |
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versions.js |
Puppeteer
API | FAQ | Contributing | Troubleshooting
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.
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 (Single-Page Application) and generate pre-rendered content (i.e. "SSR" (Server-Side Rendering)).
- 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.
- Test Chrome Extensions.
Getting Started
Installation
To use Puppeteer in your project, run:
npm i puppeteer
# or "yarn add puppeteer"
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 (customizable through Environment Variables). For a version of Puppeteer purely for connection, see puppeteer-core
.
Environment Variables
Puppeteer looks for certain environment variables to aid its operations. If Puppeteer doesn't find them in the environment during the installation step, a lowercased variant of these variables will be used from the npm config.
HTTP_PROXY
,HTTPS_PROXY
,NO_PROXY
- defines HTTP proxy settings that are used to download and run the browser.PUPPETEER_SKIP_CHROMIUM_DOWNLOAD
- do not download bundled Chromium during installation step.PUPPETEER_TMP_DIR
- defines the directory to be used by Puppeteer for creating temporary files. Defaults toos.tmpdir()
.PUPPETEER_DOWNLOAD_HOST
- overwrite URL prefix that is used to download Chromium. Note: this includes protocol and might even include path prefix. Defaults tohttps://storage.googleapis.com
.PUPPETEER_DOWNLOAD_PATH
- overwrite the path for the downloads folder. Defaults to<root>/.local-chromium
, where<root>
is Puppeteer's package root.PUPPETEER_CHROMIUM_REVISION
- specify a certain version of Chromium you'd like Puppeteer to use. Seepuppeteer.launch
on how executable path is inferred.PUPPETEER_EXECUTABLE_PATH
- specify an executable path to be used inpuppeteer.launch
.PUPPETEER_PRODUCT
- specify which browser you'd like Puppeteer to use. Must be one ofchrome
orfirefox
. This can also be used during installation to fetch the recommended browser binary. Settingproduct
programmatically inpuppeteer.launch
supersedes this environment variable. The product is exposed inpuppeteer.product
PUPPETEER_EXPERIMENTAL_CHROMIUM_MAC_ARM
— specify Puppeteer download Chromium for Apple M1. On Apple M1 devices Puppeteer by default downloads the version for Intel's processor which runs via Rosetta. It works without any problems, however, with this option, you should get more efficient resource usage (CPU and RAM) that could lead to a faster execution time.
:::danger
Puppeteer is only guaranteed to work with the bundled Chromium, use at your own risk.
:::
:::caution
PUPPETEER_*
env variables are not accounted for in puppeteer-core
.
:::
puppeteer-core
Every release since v1.7.0 we publish two packages:
puppeteer
is a product for browser automation. When installed, it downloads a version of
Chromium, which it then drives using puppeteer-core
. Being an end-user product, puppeteer
supports a bunch of convenient PUPPETEER_*
env variables to tweak its behavior.
puppeteer-core
is a library to help drive anything that supports DevTools protocol. puppeteer-core
doesn't download Chromium when installed. Being a library, puppeteer-core
is fully driven
through its programmatic interface and disregards all the PUPPETEER_*
env variables.
To sum up, the only differences between puppeteer-core
and puppeteer
are:
puppeteer-core
doesn't automatically download Chromium when installed.puppeteer-core
ignores allPUPPETEER_*
env variables.
In most cases, you'll be fine using the puppeteer
package.
However, you should use puppeteer-core
if:
- you're building another end-user product or library atop of DevTools protocol. For example, one might build a PDF generator using
puppeteer-core
and write a custominstall.js
script that downloadsheadless_shell
instead of Chromium to save disk space. - you're bundling Puppeteer to use in Chrome Extension / browser with the DevTools protocol where downloading an additional Chromium binary is unnecessary.
- you're building a set of tools where
puppeteer-core
is one of the ingredients and you want to postponeinstall.js
script execution until Chromium is about to be used.
When using puppeteer-core
, remember to change the include line:
const puppeteer = require('puppeteer-core');
You will then need to call puppeteer.connect
or puppeteer.launch
with an explicit executablePath
or channel
option.
Usage
Puppeteer follows the latest maintenance LTS version of Node.
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 800×600px, 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
and related methods like Page.evaluateOnNewDocument
and Page.exposeFunction
.
Working with Chrome Extensions
Puppeteer can be used for testing Chrome Extensions.
:::caution
Extensions in Chrome / Chromium currently only work in non-headless mode and experimental Chrome headless mode.
:::
The following is code for getting a handle to the background page of an extension whose source is located in ./my-extension
:
const puppeteer = require('puppeteer');
(async () => {
const pathToExtension = require('path').join(__dirname, 'my-extension');
const browser = await puppeteer.launch({
headless: 'chrome',
args: [
`--disable-extensions-except=${pathToExtension}`,
`--load-extension=${pathToExtension}`,
],
});
const backgroundPageTarget = await browser.waitForTarget(
target => target.type() === 'background_page'
);
const backgroundPage = await backgroundPageTarget.page();
// Test the background page as you would any other page.
await browser.close();
})();
:::note
Chrome Manifest V3 extensions have a background ServiceWorker of type 'service_worker', instead of a page of type 'background_page'.
:::
:::note
It is not yet possible to test extension popups or content scripts.
:::
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'});
You can also use Puppeteer with Firefox Nightly (experimental support). 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 browser user profile which it cleans up on every run.
Resources
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 inpage.evaluate()
:page.on('console', msg => console.log('PAGE LOG:', msg.text())); await page.evaluate(() => console.log(`url is ${location.href}`));
-
Use debugger in application code browser
There are two execution context: node.js that is running test code, and the browser running application code being tested. This lets you debug code in the application code browser; ie code inside
evaluate()
.-
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 / adddebugger
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.
-
-
Use debugger in node.js
This will let you debug test code. For example, you can step over
await page.click()
in the node.js script and see the click happen in the application code browser.Note that you won't be able to run
await page.click()
in DevTools console due to this Chromium bug. So if you want to try something out, you have to add it to your test file.-
Add
debugger;
to your test, eg:debugger; await page.click('a[target=_blank]');
-
Set
headless
tofalse
-
Run
node --inspect-brk
, egnode --inspect-brk node_modules/.bin/jest tests
-
In Chrome open
chrome://inspect/#devices
and clickinspect
-
In the newly opened test browser, type
F8
to resume test execution -
Now your
debugger
will be hit and you can debug in the test browser
-
-
Enable verbose logging - internal DevTools protocol traffic will be logged via the
debug
module under thepuppeteer
namespace.# Basic verbose logging env DEBUG="puppeteer:*" node script.js # 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'
-
Debug your Puppeteer (node) code easily, using ndb
-
npm install -g ndb
(or even better, use npx!) -
add a
debugger
to your Puppeteer (node) code -
add
ndb
(ornpx ndb
) before your test command. For example:ndb jest
orndb mocha
(ornpx ndb jest
/npx ndb mocha
) -
debug your test inside chromium like a boss!
Contributing
Check out our contributing guide to get an overview of Puppeteer development.