8.8 KiB
| id | title |
|---|---|
| library | Playwright Library |
Playwright can either be used as a part of the Playwright Test, or as a standalone library. If you are working on an application that utilizes Playwright capabilities or you are using Playwright with another test runner, read on.
Usage
Use npm or Yarn to install Playwright library in your Node.js project. See system requirements.
npm i -D playwright
This single command downloads the Playwright NPM package and browser binaries for Chromium, Firefox and WebKit. To modify this behavior see managing browsers.
Once installed, you can require Playwright in a Node.js script, and launch any of the 3 browsers (chromium, firefox and webkit).
const { chromium } = require('playwright');
(async () => {
const browser = await chromium.launch();
// Create pages, interact with UI elements, assert values
await browser.close();
})();
Playwright APIs are asynchronous and return Promise objects. Our code examples use the async/await pattern to ease readability. The code is wrapped in an unnamed async arrow function which is invoking itself.
(async () => { // Start of async arrow function
// Function code
// ...
})(); // End of the function and () to invoke itself
First script
In our first script, we will navigate to whatsmyuseragent.org and take a screenshot in WebKit.
const { webkit } = require('playwright');
(async () => {
const browser = await webkit.launch();
const page = await browser.newPage();
await page.goto('http://whatsmyuseragent.org/');
await page.screenshot({ path: `example.png` });
await browser.close();
})();
By default, Playwright runs the browsers in headless mode. To see the browser UI, pass the headless: false flag while launching the browser. You can also use slowMo to slow down execution. Learn more in the debugging tools section.
firefox.launch({ headless: false, slowMo: 50 });
Record scripts
Command Line Interface CLI can be used to record user interactions and generate JavaScript code.
npx playwright codegen wikipedia.org
TypeScript support
Playwright includes built-in support for TypeScript. Type definitions will be imported automatically. It is recommended to use type-checking to improve the IDE experience.
In JavaScript
Add the following to the top of your JavaScript file to get type-checking in VS Code or WebStorm.
//@ts-check
// ...
Alternatively, you can use JSDoc to set types for variables.
/** @type {import('playwright').Page} */
let page;
In TypeScript
TypeScript support will work out-of-the-box. Types can also be imported explicitly.
let page: import('playwright').Page;
System requirements
Playwright requires Node.js version 12 or above. The browser binaries for Chromium, Firefox and WebKit work across the 3 platforms (Windows, macOS, Linux):
Windows
Works with Windows and Windows Subsystem for Linux (WSL).
macOS
Requires 10.14 (Mojave) or above.
Linux
Depending on your Linux distribution, you might need to install additional dependencies to run the browsers.
:::note Only Ubuntu 18.04 and Ubuntu 20.04 are officially supported. :::
See also in the Command Line Interface which has a command to install all necessary dependencies automatically for Ubuntu LTS releases.
Managing browser binaries
Each version of Playwright needs specific versions of browser binaries to operate. By default, Playwright downloads Chromium, WebKit and Firefox browsers into the OS-specific cache folders:
%USERPROFILE%\AppData\Local\ms-playwrighton Windows~/Library/Caches/ms-playwrighton MacOS~/.cache/ms-playwrighton Linux
npm i -D playwright
These browsers will take a few hundred megabytes of disk space when installed:
du -hs ~/Library/Caches/ms-playwright/*
281M chromium-XXXXXX
187M firefox-XXXX
180M webkit-XXXX
You can override default behavior using environment variables. When installing Playwright, ask it to download browsers into a specific location:
# Linux/macOS
PLAYWRIGHT_BROWSERS_PATH=$HOME/pw-browsers npm i -D playwright
# Windows with cmd.exe
set PLAYWRIGHT_BROWSERS_PATH=%USERPROFILE%\pw-browsers
npm i -D playwright
# Windows with PowerShell
$env:PLAYWRIGHT_BROWSERS_PATH="$env:USERPROFILE\pw-browsers"
npm i -D playwright
When running Playwright scripts, ask it to search for browsers in a shared location.
# Linux/macOS
PLAYWRIGHT_BROWSERS_PATH=$HOME/pw-browsers node playwright-script.js
# Windows with cmd.exe
set PLAYWRIGHT_BROWSERS_PATH=%USERPROFILE%\pw-browsers
node playwright-script.js
# Windows with PowerShell
$env:PLAYWRIGHT_BROWSERS_PATH="$env:USERPROFILE\pw-browsers"
node playwright-script.js
Or you can opt into the hermetic install and place binaries in the local folder:
# Linux/macOS
# Places binaries to node_modules/playwright
PLAYWRIGHT_BROWSERS_PATH=0 npm i -D playwright
# Windows with cmd.exe
# Places binaries to node_modules\playwright
set PLAYWRIGHT_BROWSERS_PATH=0
npm i -D playwright
# Windows with PowerShell
# Places binaries to node_modules\playwright
$env:PLAYWRIGHT_BROWSERS_PATH=0
npm i -D playwright
Playwright keeps track of packages that need those browsers and will garbage collect them as you update Playwright to the newer versions.
:::note
Developers can opt-in in this mode via exporting PLAYWRIGHT_BROWSERS_PATH=$HOME/pw-browsers in their .bashrc.
:::
Install behind a firewall or a proxy
By default, Playwright downloads browsers from Microsoft's CDN.
Sometimes companies maintain an internal proxy that blocks direct access to the public resources. In this case, Playwright can be configured to download browsers via a proxy server.
# Linux/macOS
HTTPS_PROXY=https://192.0.2.1 npm i -D playwright
# Windows with cmd.exe
set HTTPS_PROXY=https://192.0.2.1
npm i -D playwright
# Windows with PowerShell
$env:HTTPS_PROXY="https://192.0.2.1"
npm i -D playwright
Download from artifact repository
By default, Playwright downloads browsers from Microsoft's CDN.
Sometimes companies maintain an internal artifact repository to host browser
binaries. In this case, Playwright can be configured to download from a custom
location using the PLAYWRIGHT_DOWNLOAD_HOST env variable.
# Linux/macOS
PLAYWRIGHT_DOWNLOAD_HOST=192.0.2.1 npm i -D playwright
# Windows with cmd.exe
set PLAYWRIGHT_DOWNLOAD_HOST=192.0.2.1
npm i -D playwright
# Windows with PowerShell
$env:PLAYWRIGHT_DOWNLOAD_HOST="192.0.2.1"
npm i -D playwright
It is also possible to use a per-browser download hosts using PLAYWRIGHT_CHROMIUM_DOWNLOAD_HOST, PLAYWRIGHT_FIREFOX_DOWNLOAD_HOST and PLAYWRIGHT_WEBKIT_DOWNLOAD_HOST env variables that
take precedence over PLAYWRIGHT_DOWNLOAD_HOST.
# Linux/macOS
PLAYWRIGHT_FIREFOX_DOWNLOAD_HOST=203.0.113.3 PLAYWRIGHT_DOWNLOAD_HOST=192.0.2.1 npm i -D playwright
Skip browser downloads
In certain cases, it is desired to avoid browser downloads altogether because browser binaries are managed separately.
This can be done by setting PLAYWRIGHT_SKIP_BROWSER_DOWNLOAD variable before installation.
# Linux/macOS
PLAYWRIGHT_SKIP_BROWSER_DOWNLOAD=1 npm i -D playwright
# Windows with cmd.exe
set PLAYWRIGHT_SKIP_BROWSER_DOWNLOAD=1
npm i -D playwright
# Windows with PowerShell
$env:PLAYWRIGHT_SKIP_BROWSER_DOWNLOAD=1
npm i -D playwright
Download single browser binary
Playwright ships three packages that bundle only a single browser:
:::note All configuration environment variables also apply to these packages. :::
Using these packages is as easy as using a regular Playwright:
Install a specific package
npm i -D playwright-webkit
Require package
// Notice a proper package name in require
const { webkit } = require('playwright-webkit');
(async () => {
const browser = await webkit.launch();
// ...
})();
Stale browser removal
Playwright keeps track of the clients that use its browsers. When there are no more clients that require particular version of the browser, that version is deleted from the system. That way you can safely use Playwright instances of different versions and at the same time, you don't waste disk space for the browsers that are no longer in use.
To opt-out from the unused browser removal, you can set the PLAYWRIGHT_SKIP_BROWSER_GC=1 environment variable.