browser-pool
# (DEPRECATED) Browser Pool - the headless browser manager > **DEPRECATED!** > > The Browser Pool package now lives in the [`crawlee`](https://github.com/apify/crawlee) repository - submit all your issues and PRs there. This repository is no longer actively maintained! Browser Pool is a small, but powerful and extensible library, that allows you to seamlessly control multiple headless browsers at the same time with only a little configuration, and a single function call. Currently it supports [Puppeteer](https://github.com/puppeteer/puppeteer), [Playwright](https://github.com/microsoft/playwright) and it can be easily extended with plugins. We created Browser Pool because we regularly needed to execute tasks concurrently in many headless browsers and their pages, but we did not want to worry about launching browsers, closing browsers, restarting them after crashes and so on. We also wanted to easily and reliably manage the whole browser / page lifecycle. You can use Browser Pool for scraping the internet at scale, testing your website in multiple browsers at the same time or launching web automation robots. We're interested to hear about your use cases in the [Discussions](https://github.com/apify/browser-pool/discussions). <!-- toc --> - [Installation](#installation) - [Usage](#usage) - [Launching multiple browsers](#launching-multiple-browsers) - [Features](#features) * [Simple configuration](#simple-configuration) * [Proxy management](#proxy-management) * [Lifecycle management with hooks](#lifecycle-management-with-hooks) * [Manipulating playwright context using `pageOptions` or `launchOptions`](#manipulating-playwright-context-using-pageoptions-or-launchoptions) * [Single API for common operations](#single-api-for-common-operations) * [Graceful browser closing](#graceful-browser-closing) * [Changing browser fingerprints a.k.a. browser signatures](#changing-browser-fingerprints-aka-browser-signatures) * [(UNSTABLE) Extensibility with plugins](#unstable-extensibility-with-plugins) - [API Reference](#api-reference) <!-- tocstop --> ## Installation Use NPM or Yarn to install `browser-pool`. Note that `browser-pool` does not come preinstalled with browser automation libraries. This allows you to choose your own libraries and their versions and it also makes `browser-pool` much smaller. Run this command to install `browser-pool` and the `playwright` browser automation library. ```bash npm install browser-pool playwright ``` ## Usage This simple example shows how to open a page in a browser using Browser Pool. We use the provided `PlaywrightPlugin` to wrap a Playwright installation of your own. By calling `browserPool.newPage()` you launch a new Firefox browser and open a new page in that browser. ```js const { BrowserPool, PlaywrightPlugin } = require('browser-pool'); const playwright = require('playwright'); const browserPool = new BrowserPool({ browserPlugins: [new PlaywrightPlugin(playwright.chromium)], }); // An asynchronous IIFE (immediately invoked function expression) // allows us to use the 'await' keyword. (async () => { // Launches Chromium with Playwright and returns a Playwright Page. const page1 = await browserPool.newPage(); // You can interact with the page as you're used to. await page1.goto('https://example.com'); // When you're done, close the page. await page1.close(); // Opens a second page in the same browser. const page2 = await browserPool.newPage(); // When everything's finished, tear down the pool. await browserPool.destroy(); })(); ``` > Browser Pool uses the same asynchronous API as the underlying automation libraries which means extensive use of Promises and the `async` / `await` pattern. [Visit MDN to learn more](https://developer.mozilla.org/en-US/docs/Learn/JavaScript/Asynchronous/Async_await). ## Launching multiple browsers The basic example shows how to launch a single browser, but the purpose of Browser Pool is to launch many browsers. This is done automatically in the background. You only need to provide the relevant plugins and call `browserPool.newPage()`. ```js const { BrowserPool, PlaywrightPlugin } = require('browser-pool'); const playwright = require('playwright'); const browserPool = new BrowserPool({ browserPlugins: [ new PlaywrightPlugin(playwright.chromium), new PlaywrightPlugin(playwright.firefox), new PlaywrightPlugin(playwright.webkit), ], }); (async () => { // Open 4 pages in 3 browsers. The browsers are launched // in a round-robin fashion based on the plugin order. const chromiumPage = await browserPool.newPage(); const firefoxPage = await browserPool.newPage(); const webkitPage = await browserPool.newPage(); const chromiumPage2 = await browserPool.newPage(); // Don't forget to close pages / destroy pool when you're done. })(); ``` This round-robin way of opening pages may not be useful for you, if you need to consistently run tasks in multiple environments. For that, there's the `newPageWithEachPlugin` function. ```js const { BrowserPool, PlaywrightPlugin, PuppeteerPlugin } = require('browser-pool'); const playwright = require('playwright'); const puppeteer = require('puppeteer'); const browserPool = new BrowserPool({ browserPlugins: [ new PlaywrightPlugin(playwright.chromium), new PuppeteerPlugin(puppeteer), ], }); (async () => { const pages = await browserPool.newPageWithEachPlugin(); const promises = pages.map(async page => { // Run some task with each page // pages are in order of plugins: // [playwrightPage, puppeteerPage] await page.close(); }); await Promise.all(promises); // Continue with some more work. })(); ``` ## Features Besides a simple interface for launching browsers, Browser Pool includes other helpful features that make browser management more convenient. ### Simple configuration You can easily set the maximum number of pages that can be open in a given browser and also the maximum number of pages to process before a browser [is retired](#graceful-browser-closing). ```js const browserPool = new BrowserPool({ maxOpenPagesPerBrowser: 20, retireBrowserAfterPageCount: 100, }); ``` You can configure the browser launch options either right in the plugins: ```js const playwrightPlugin = new PlaywrightPlugin(playwright.chromium, { launchOptions: { headless: true, } }) ``` Or dynamically in [pre-launch hooks](#lifecycle-management-with-hooks): ```js const browserPool = new BrowserPool({ preLaunchHooks: [(pageId, launchContext) => { if (pageId === 'headful') { launchContext.launchOptions.headless = false; } }] }); ``` ### Proxy management When scraping at scale or testing websites from multiple geolocations, one often needs to use proxy servers. Setting up an authenticated proxy in Puppeteer can be cumbersome, so we created a helper that does all the heavy lifting for you. Simply provide a proxy URL with authentication credentials, and you're done. It works the same for Playwright too. ```js const puppeteerPlugin = new PuppeteerPlugin(puppeteer, { proxyUrl: 'http://<username>:<password>@proxy.com:8000' }); ``` > We plan to extend this by adding a proxy-per-page functionality, > allowing you to rotate proxies per page, rather than per browser. ### Lifecycle management with hooks Browser Pool allows you to manage the full browser / page lifecycle by attaching hooks to the most important events. Asynchronous hooks are supported, and their execution order is guaranteed. The first parameter of each hook is either a `pageId` for the hooks executed before a `page` is created or a `page` afterwards. This is useful to keep track of which hook was triggered by which `newPage()` call. ```js const browserPool = new BrowserPool({ browserPlugins: [ new PlaywrightPlugin(playwright.chromium), ], preLaunchHooks: [(pageId, launchContext) => { // You can use pre-launch hooks to make dynamic changes // to the launchContext, such as changing a proxyUrl // or updating the browser launchOptions pageId === 'my-page' // true }], postPageCreateHooks: [(page, browserController) => { // It makes sense to make global changes to pages // in post-page-create hooks. For example, you can // inject some JavaScript library, such as jQuery. browserPool.getPageId(page) === 'my-page' // true }] }); await browserPool.newPage({ id: 'my-page' }); ``` > See the API Documentation for all hooks and their arguments. ### Manipulating playwright context using `pageOptions` or `launchOptions` Playwright allows customizing multiple browser attributes by browser context. You can customize some of them once the context is created, but some need to be customized within its creation. This part of the documentation should explain how you can effectively customize the browser context. First of all, let's take a look at what kind of context strategy you chose. You can choose between two strategies by `useIncognitoPages` `LaunchContext` option. Suppose you decide to keep `useIncognitoPages` default `false` and create a shared context across all pages launched by one browser. In this case, you should pass the `contextOptions` as a `launchOptions` since the context is created within the new browser launch. The `launchOptions` corresponds to these [playwright options](https://playwright.dev/docs/api/class-browsertype#browsertypelaunchpersistentcontextuserdatadir-options). As you can see, these options contain not only ordinary playwright launch options but also the context options. If you set `useIncognitoPages` to `true`, you will create a new context within each new page, which allows you to handle each page its cookies and application data. This approach allows you to pass the context options as `pageOptions` because a new context is created once you create a new page. In this case, the `pageOptions` corresponds to these [playwright options](https://playwright.dev/docs/api/class-browser#browsernewpageoptions). **Changing context options with `LaunchContext`:** This will only work if you keep the default value for `useIncognitoPages` (`false`). ```javascript const browserPool = new BrowserPool({ browserPlugins: [ new PlaywrightPlugin( playwright.chromium, { launchOptions: { deviceScaleFactor: 2, }, }, ), ], }); ``` **Changing context options with `browserPool.newPage` options:** ```javascript const browserPool = new BrowserPool({ browserPlugins: [ new PlaywrightPlugin( playwright.chromium, { useIncognitoPages: true, // You must turn on incognito pages. launchOptions: { // launch options headless: false, devtools: true, }, }, ), ], }); (async () => { // Launches Chromium with Playwright and returns a Playwright Page. const page = await browserPool.newPage({ pageOptions: { // context options deviceScaleFactor: 2, colorScheme: 'light', locale: 'de-DE', }, }); })(); ``` **Changing context options with `prePageCreateHooks` options:** ```javascript const browserPool = new BrowserPool({ browserPlugins: [ new PlaywrightPlugin( playwright.chromium, { useIncognitoPages: true, launchOptions: { // launch options headless: false, devtools: true, }, }, ), ], prePageCreateHooks: [ (pageId, browserController, pageOptions) => { pageOptions.deviceScaleFactor = 2; pageOptions.colorScheme = 'dark'; pageOptions.locale = 'de-DE'; // You must modify the 'pageOptions' object, not assign to the variable. // pageOptions = {deviceScaleFactor: 2, ...etc} => This will not work! }, ], }); (async () => { // Launches Chromium with Playwright and returns a Playwright Page. const page = await browserPool.newPage(); })(); ``` ### Single API for common operations Puppeteer and Playwright handle some things differently. Browser Pool attempts to remove those differences for the most common use-cases. ```js // Playwright const cookies = await context.cookies(); await context.addCookies(cookies); // Puppeteer const cookies = await page.cookies(); await page.setCookie(...cookies); // BrowserPool uses the same API for all plugins const cookies = await browserController.getCookies(page); await browserController.setCookies(page, cookies); ``` ### Graceful browser closing With Browser Pool, browsers are not closed, but retired. A retired browser will no longer open new pages, but it will wait until the open pages are closed, allowing your running tasks to finish. If a browser gets stuck in limbo, it will be killed after a timeout to prevent hanging browser processes. ### Changing browser fingerprints a.k.a. browser signatures Changing browser fingerprints is beneficial for avoiding getting blocked and simulating real user browsers. With Browser Pool, you can do this otherwise complicated technique by enabling the `useFingerprints` option. The fingerprints are by default tied to the respective session (and proxy URLs) to not use the same unique fingerprint from various IP addresses. You can disable this behavior in the [`fingerprintOptions`](#new_BrowserPool_new). Using `fingerprintsOptions`, you can also control which fingerprints are generated. You can control parameters as browser, operating system, and browser versions. ### (UNSTABLE) Extensibility with plugins A new super cool browser automation library appears? No problem, we add a simple plugin to Browser Pool and it automagically works. > The BrowserPlugin and BrowserController interfaces are unstable and may > change if we find some implementation to be sub-optimal. ## API Reference All public classes, methods and their parameters can be inspected in this API reference. <a name="module_browser-pool"></a> ### browser-pool The `browser-pool` module exports three constructors. One for `BrowserPool` itself and two for the included Puppeteer and Playwright plugins. **Example:** ```js const { BrowserPool, PuppeteerPlugin, PlaywrightPlugin } = require('browser-pool'); const puppeteer = require('puppeteer'); const playwright = require('playwright'); const browserPool = new BrowserPool({ browserPlugins: [ new PuppeteerPlugin(puppeteer), new PlaywrightPlugin(playwright.chromium), ] }); ``` **Properties** | Name | Type | | --- | --- | | BrowserPool | [<code>BrowserPool</code>](#BrowserPool) | | PuppeteerPlugin | <code>PuppeteerPlugin</code> | | PlaywrightPlugin | <code>PlaywrightPlugin</code> | * * * <a name="BrowserPool"></a> ### BrowserPool The `BrowserPool` class is the most important class of the `browser-pool` module. It manages opening and closing of browsers and their pages and its constructor options allow easy configuration of the browsers' and pages' lifecycle. The most important and useful constructor options are the various lifecycle hooks. Those allow you to sequentially call a list of (asynchronous) functions at each stage of the browser / page lifecycle. **Example:** ```js const { BrowserPool, PlaywrightPlugin } = require('browser-pool'); const playwright = require('playwright'); const browserPool = new BrowserPool({ browserPlugins: [ new PlaywrightPlugin(playwright.chromium)], preLaunchHooks: [(pageId, launchContext) => { // do something before a browser gets launched launchContext.launchOptions.headless = false; }], postLaunchHooks: [(pageId, browserController) => { // manipulate the browser right after launch console.dir(browserController.browser.contexts()); }], prePageCreateHooks: [(pageId, browserController) => { if (pageId === 'my-page') { // make changes right before a specific page is created } }], postPageCreateHooks: [async (page, browserController) => { // update some or all new pages await page.evaluate(() => { // now all pages will have 'foo' window.foo = 'bar' }) }], prePageCloseHooks: [async (page, browserController) => { // collect information just before a page closes await page.screenshot(); }], postPageCloseHooks: [(pageId, browserController) => { // clean up or log after a job is done console.log('Page closed: ', pageId) }] }); ``` * [BrowserPool](#BrowserPool) * [`new BrowserPool(options)`](#new_BrowserPool_new) * [`.newPage(options)`](#BrowserPool+newPage) ⇒ <code>Promise.<Page></code> * [`.newPageInNewBrowser(options)`](#BrowserPool+newPageInNewBrowser) ⇒ <code>Promise.<Page></code> * [`.newPageWithEachPlugin(optionsList)`](#BrowserPool+newPageWithEachPlugin) ⇒ <code>Promise.<Array.<Page>></code> * [`.getBrowserControllerByPage(page)`](#BrowserPool+getBrowserControllerByPage) ⇒ [<code>BrowserController</code>](#BrowserController) * [`.getPage(id)`](#BrowserPool+getPage) ⇒ <code>Page</code> * [`.getPageId(page)`](#BrowserPool+getPageId) ⇒ <code>string</code> * [`.retireBrowserController(browserController)`](#BrowserPool+retireBrowserController) * [`.retireBrowserByPage(page)`](#BrowserPool+retireBrowserByPage) * [`.retireAllBrowsers()`](#BrowserPool+retireAllBrowsers) * [`.closeAllBrowsers()`](#BrowserPool+closeAllBrowsers) ⇒ <code>Promise.<void></code> * [`.destroy()`](#BrowserPool+destroy) ⇒ <code>Promise.<void></code> * * * <a name="new_BrowserPool_new"></a> #### `new BrowserPool(options)` | Param | Type | Default | Description | | --- | --- | --- | --- | | options | <code>object</code> | | | | options.browserPlugins | [<code>Array.<BrowserPlugin></code>](#BrowserPlugin) | | Browser plugins are wrappers of browser automation libraries that allow `BrowserPool` to control browsers with those libraries. `browser-pool` comes with a `PuppeteerPlugin` and a `PlaywrightPlugin`. | | [options.maxOpenPagesPerBrowser] | <code>number</code> | <code>20</code> | Sets the maximum number of pages that can be open in a browser at the same time. Once reached, a new browser will be launched to handle the excess. | | [options.retireBrowserAfterPageCount] | <code>number</code> | <code>100</code> | Browsers tend to get bloated after processing a lot of pages. This option configures the number of processed pages after which the browser will automatically retire and close. A new browser will launch in its place. | | [options.operationTimeoutSecs] | <code>number</code> | <code>15</code> | As we know from experience, async operations of the underlying libraries, such as launching a browser or opening a new page, can get stuck. To prevent `BrowserPool` from getting stuck, we add a timeout to those operations and you can configure it with this option. | | [options.closeInactiveBrowserAfterSecs] | <code>number</code> | <code>300</code> | Browsers normally close immediately after their last page is processed. However, there could be situations where this does not happen. Browser Pool makes sure all inactive browsers are closed regularly, to free resources. | | [options.preLaunchHooks] | <code>Array.<function()></code> | | Pre-launch hooks are executed just before a browser is launched and provide a good opportunity to dynamically change the launch options. The hooks are called with two arguments: `pageId`: `string` and `launchContext`: [LaunchContext](#LaunchContext) | | [options.postLaunchHooks] | <code>Array.<function()></code> | | Post-launch hooks are executed as soon as a browser is launched. The hooks are called with two arguments: `pageId`: `string` and `browserController`: [BrowserController](#BrowserController) To guarantee order of execution before other hooks in the same browser, the [BrowserController](#BrowserController) methods cannot be used until the post-launch hooks complete. If you attempt to call `await browserController.close()` from a post-launch hook, it will deadlock the process. This API is subject to change. | | [options.prePageCreateHooks] | <code>Array.<function()></code> | | Pre-page-create hooks are executed just before a new page is created. They are useful to make dynamic changes to the browser before opening a page. The hooks are called with two arguments: `pageId`: `string`, `browserController`: [BrowserController](#BrowserController) and `pageOptions`: `object|undefined` - This only works if the underlying `BrowserController` supports new page options. So far, new page options are only supported by `PlaywrightController`. If the page options are not supported by `BrowserController` the `pageOptions` argument is `undefined`. | | [options.postPageCreateHooks] | <code>Array.<function()></code> | | Post-page-create hooks are called right after a new page is created and all internal actions of Browser Pool are completed. This is the place to make changes to a page that you would like to apply to all pages. Such as injecting a JavaScript library into all pages. The hooks are called with two arguments: `page`: `Page` and `browserController`: [BrowserController](#BrowserController) | | [options.prePageCloseHooks] | <code>Array.<function()></code> | | Pre-page-close hooks give you the opportunity to make last second changes in a page that's about to be closed, such as saving a snapshot or updating state. The hooks are called with two arguments: `page`: `Page` and `browserController`: [BrowserController](#BrowserController) | | [options.postPageCloseHooks] | <code>Array.<function()></code> | | Post-page-close hooks allow you to do page related clean up. The hooks are called with two arguments: `pageId`: `string` and `browserController`: [BrowserController](#BrowserController) | |[options.useFingerprints] | <code>boolean</code> | <code>false</code> | If true the Browser pool will automatically generate and inject fingerprints to browsers.| | [options.fingerprintsOptions] | <code>FingerprintOptions </code> | | Fingerprints options that allows customizing the fingerprinting behavior. | | [options.fingerprintsOptions.fingerprintGeneratorOptions] | | | See the [Fingerprint generator]("https://github.com/apify/fingerprint-generator#headergeneratoroptions") documentation. | | [options.fingerprintsOptions.useFingerprintPerProxyCache] | <code>boolean</code> | <code>true</code>| Fingerprints are autimatically assigned to an IP address so 1 IP equals 1 fingerprint. You can disable this behavior by settings this property to false. | | [options.fingerprintsOptions.fingerprintPerProxyCacheSize] | <code>number</code> | <code>10000</code> | Maximum number of IP to fingerprint pairs. * * * <a name="BrowserPool+newPage"></a> #### `browserPool.newPage(options)` ⇒ <code>Promise.<Page></code> Opens a new page in one of the running browsers or launches a new browser and opens a page there, if no browsers are active, or their page limits have been exceeded. | Param | Type | Description | | --- | --- | --- | | options | <code>object</code> | | | [options.id] | <code>string</code> | Assign a custom ID to the page. If you don't a random string ID will be generated. | | [options.pageOptions] | <code>object</code> | Some libraries (Playwright) allow you to open new pages with specific options. Use this property to set those options. | | [options.browserPlugin] | [<code>BrowserPlugin</code>](#BrowserPlugin) | Choose a plugin to open the page with. If none is provided, one of the pool's available plugins will be used. It must be one of the plugins browser pool was created with. If you wish to start a browser with a different configuration, see the `newPageInNewBrowser` function. | * * * <a name="BrowserPool+newPageInNewBrowser"></a> #### `browserPool.newPageInNewBrowser(options)` ⇒ <code>Promise.<Page></code> Unlike [newPage](newPage), `newPageInNewBrowser` always launches a new browser to open the page in. Use the `launchOptions` option to configure the new browser. | Param | Type | Description | | --- | --- | --- | | options | <code>object</code> | | | [options.id] | <code>string</code> | Assign a custom ID to the page. If you don't a random string ID will be generated. | | [options.pageOptions] | <code>object</code> | Some libraries (Playwright) allow you to open new pages with specific options. Use this property to set those options. | | [options.launchOptions] | <code>object</code> | Options that will be used to launch the new browser. | | [options.browserPlugin] | [<code>BrowserPlugin</code>](#BrowserPlugin) | Provide a plugin to launch the browser. If none is provided, one of the pool's available plugins will be used. If you configured `BrowserPool` to rotate multiple libraries, such as both Puppeteer and Playwright, you should always set the `browserPlugin` when using the `launchOptions` option. The plugin will not be added to the list of plugins used by the pool. You can either use one of those, to launch a specific browser, or provide a completely new configuration. | * * * <a name="BrowserPool+newPageWithEachPlugin"></a> #### `browserPool.newPageWithEachPlugin(optionsList)` ⇒ <code>Promise.<Array.<Page>></code> Opens new pages with all available plugins and returns an array of pages in the same order as the plugins were provided to `BrowserPool`. This is useful when you want to run a script in multiple environments at the same time, typically in testing or website analysis. **Example:** ```js const browserPool = new BrowserPool({ browserPlugins: [ new PlaywrightPlugin(playwright.chromium), new PlaywrightPlugin(playwright.firefox), new PlaywrightPlugin(playwright.webkit), new PuppeteerPlugin(puppeteer), ] }); const pages = await browserPool.newPageWithEachPlugin(); const [chromiumPage, firefoxPage, webkitPage, puppeteerPage] = pages; ``` | Param | Type | | --- | --- | | optionsList | <code>Array.<object></code> | * * * <a name="BrowserPool+getBrowserControllerByPage"></a> #### `browserPool.getBrowserControllerByPage(page)` ⇒ [<code>BrowserController</code>](#BrowserController) Retrieves a [BrowserController](#BrowserController) for a given page. This is useful when you're working only with pages and need to access the browser manipulation functionality. You could access the browser directly from the page, but that would circumvent `BrowserPool` and most likely cause weird things to happen, so please always use `BrowserController` to control your browsers. The function returns `undefined` if the browser is closed. | Param | Type | Description | | --- | --- | --- | | page | <code>Page</code> | Browser plugin page | * * * <a name="BrowserPool+getPage"></a> #### `browserPool.getPage(id)` ⇒ <code>Page</code> If you provided a custom ID to one of your pages or saved the randomly generated one, you can use this function to retrieve the page. If the page is no longer open, the function will return `undefined`. | Param | Type | | --- | --- | | id | <code>string</code> | * * * <a name="BrowserPool+getPageId"></a> #### `browserPool.getPageId(page)` ⇒ <code>string</code> Page IDs are used throughout `BrowserPool` as a method of linking events. You can use a page ID to track the full lifecycle of the page. It is created even before a browser is launched and stays with the page until it's closed. | Param | Type | | --- | --- | | page | <code>Page</code> | * * * <a name="BrowserPool+retireBrowserController"></a> #### `browserPool.retireBrowserController(browserController)` Removes a browser controller from the pool. The underlying browser will be closed after all its pages are closed. | Param | Type | | --- | --- | | browserController | [<code>BrowserController</code>](#BrowserController) | * * * <a name="BrowserPool+retireBrowserByPage"></a> #### `browserPool.retireBrowserByPage(page)` Removes a browser from the pool. It will be closed after all its pages are closed. | Param | Type | | --- | --- | | page | <code>Page</code> | * * * <a name="BrowserPool+retireAllBrowsers"></a> #### `browserPool.retireAllBrowsers()` Removes all active browsers from the pool. The browsers will be closed after all their pages are closed. * * * <a name="BrowserPool+closeAllBrowsers"></a> #### `browserPool.closeAllBrowsers()` ⇒ <code>Promise.<void></code> Closes all managed browsers without waiting for pages to close. * * * <a name="BrowserPool+destroy"></a> #### `browserPool.destroy()` ⇒ <code>Promise.<void></code> Closes all managed browsers and tears down the pool. * * * <a name="BrowserController"></a> ### BrowserController The `BrowserController` serves two purposes. First, it is the base class that specialized controllers like `PuppeteerController` or `PlaywrightController` extend. Second, it defines the public interface of the specialized classes which provide only private methods. Therefore, we do not keep documentation for the specialized classes, because it's the same for all of them. **Properties** | Name | Type | Description | | --- | --- | --- | | id | <code>string</code> | | | browserPlugin | [<code>BrowserPlugin</code>](#BrowserPlugin) | The `BrowserPlugin` instance used to launch the browser. | | browser | <code>Browser</code> | Browser representation of the underlying automation library. | | launchContext | [<code>LaunchContext</code>](#LaunchContext) | The configuration the browser was launched with. | * [BrowserController](#BrowserController) * [`.close()`](#BrowserController+close) ⇒ <code>Promise.<void></code> * [`.kill()`](#BrowserController+kill) ⇒ <code>Promise.<void></code> * [`.setCookies(page, cookies)`](#BrowserController+setCookies) ⇒ <code>Promise.<void></code> * [`.getCookies(page)`](#BrowserController+getCookies) ⇒ <code>Promise.<Array.<object>></code> * * * <a name="BrowserController+close"></a> #### `browserController.close()` ⇒ <code>Promise.<void></code> Gracefully closes the browser and makes sure there will be no lingering browser processes. Emits 'browserClosed' event. * * * <a name="BrowserController+kill"></a> #### `browserController.kill()` ⇒ <code>Promise.<void></code> Immediately kills the browser process. Emits 'browserClosed' event. * * * <a name="BrowserController+setCookies"></a> #### `browserController.setCookies(page, cookies)` ⇒ <code>Promise.<void></code> | Param | Type | | --- | --- | | page | <code>Object</code> | | cookies | <code>Array.<object></code> | * * * <a name="BrowserController+getCookies"></a> #### `browserController.getCookies(page)` ⇒ <code>Promise.<Array.<object>></code> | Param | Type | | --- | --- | | page | <code>Object</code> | * * * <a name="BrowserPlugin"></a> ### BrowserPlugin The `BrowserPlugin` serves two purposes. First, it is the base class that specialized controllers like `PuppeteerPlugin` or `PlaywrightPlugin` extend. Second, it allows the user to configure the automation libraries and feed them to [BrowserPool](#BrowserPool) for use. **Properties** | Name | Type | Default | Description | | --- | --- | --- | --- | | [useIncognitoPages] | <code>boolean</code> | <code>false</code> | By default pages share the same browser context. If set to true each page uses its own context that is destroyed once the page is closed or crashes. | | [userDataDir] | <code>object</code> | | Path to a User Data Directory, which stores browser session data like cookies and local storage. | * * * <a name="new_BrowserPlugin_new"></a> #### `new BrowserPlugin(library, [options])` | Param | Type | Description | | --- | --- | --- | | library | <code>object</code> | Each plugin expects an instance of the object with the `.launch()` property. For Puppeteer, it is the `puppeteer` module itself, whereas for Playwright it is one of the browser types, such as `puppeteer.chromium`. `BrowserPlugin` does not include the library. You can choose any version or fork of the library. It also keeps `browser-pool` installation small. | | [options] | <code>object</code> | | | [options.launchOptions] | <code>object</code> | Options that will be passed down to the automation library. E.g. `puppeteer.launch(launchOptions);`. This is a good place to set options that you want to apply as defaults. To dynamically override those options per-browser, see the `preLaunchHooks` of [BrowserPool](#BrowserPool). | | [options.proxyUrl] | <code>string</code> | Automation libraries configure proxies differently. This helper allows you to set a proxy URL without worrying about specific implementations. It also allows you use an authenticated proxy without extra code. | * * * <a name="LaunchContext"></a> ### LaunchContext `LaunchContext` holds information about the launched browser. It's useful to retrieve the `launchOptions`, the proxy the browser was launched with or any other information user chose to add to the `LaunchContext` by calling its `extend` function. This is very useful to keep track of browser-scoped values, such as session IDs. **Properties** | Name | Type | Description | | --- | --- | --- | | id | <code>string</code> | To make identification of `LaunchContext` easier, `BrowserPool` assigns the `LaunchContext` an `id` that's equal to the `id` of the page that triggered the browser launch. This is useful, because many pages share a single launch context (single browser). | | browserPlugin | [<code>BrowserPlugin</code>](#BrowserPlugin) | The `BrowserPlugin` instance used to launch the browser. | | launchOptions | <code>object</code> | The actual options the browser was launched with, after changes. Those changes would be typically made in pre-launch hooks. | | [useIncognitoPages] | <code>boolean</code> | By default pages share the same browser context. If set to true each page uses its own context that is destroyed once the page is closed or crashes. | | [userDataDir] | <code>object</code> | Path to a User Data Directory, which stores browser session data like cookies and local storage. | * [LaunchContext](#LaunchContext) * [`.proxyUrl`](#LaunchContext+proxyUrl) * [`.proxyUrl`](#LaunchContext+proxyUrl) ⇒ <code>string</code> * [`.extend(fields)`](#LaunchContext+extend) * * * <a name="LaunchContext+proxyUrl"></a> #### `launchContext.proxyUrl` Sets a proxy URL for the browser. Use `undefined` to unset existing proxy URL. | Param | Type | | --- | --- | | url | <code>string</code> | * * * <a name="LaunchContext+proxyUrl"></a> #### `launchContext.proxyUrl` ⇒ <code>string</code> Returns the proxy URL of the browser. * * * <a name="LaunchContext+extend"></a> #### `launchContext.extend(fields)` Extend the launch context with any extra fields. This is useful to keep state information relevant to the browser being launched. It ensures that no internal fields are overridden and should be used instead of property assignment. | Param | Type | | --- | --- | | fields | <code>object</code> | * * *