Implementation:Microsoft Playwright BrowserDispatcher

Knowledge Sources	Microsoft_Playwright
Domains	Dispatcher, Browser
Last Updated	2026-02-12 00:00 GMT

Overview

Concrete tool for exposing server-side Browser objects over the Playwright RPC protocol provided by the Playwright library.

Description

The `BrowserDispatcher` class extends `Dispatcher` and implements `channels.BrowserChannel` to bridge server-side `Browser` instances to remote clients. It dispatches `context` events when new browser contexts are created and a `close` event on disconnection. The class supports options for `ignoreStopAndKill` (preventing browser closure) and `isolateContexts` (only exposing contexts created through this dispatcher). It provides `newContext` for creating browser contexts, `newBrowserCDPSession` for raw CDP access (Chromium only), `startTracing`/`stopTracing` for Chromium tracing, and `close`/`killForTests` for lifecycle management.

Usage

Use BrowserDispatcher when the protocol layer needs to expose a launched or connected browser instance to Playwright clients over the RPC channel.

Code Reference

Source Location

• Repository: Microsoft_Playwright
• File: packages/playwright-core/src/server/dispatchers/browserDispatcher.ts

Signature

export class BrowserDispatcher extends Dispatcher<Browser, channels.BrowserChannel, BrowserTypeDispatcher> implements channels.BrowserChannel {
  _type_Browser: boolean;
  constructor(scope: BrowserTypeDispatcher, browser: Browser, options?: BrowserDispatcherOptions);
  _didClose(): void;
  async newContext(params: channels.BrowserNewContextParams, progress: Progress): Promise<channels.BrowserNewContextResult>;
  async close(params: channels.BrowserCloseParams, progress: Progress): Promise<void>;
  async killForTests(params: channels.BrowserKillForTestsParams, progress: Progress): Promise<void>;
  async newBrowserCDPSession(params: channels.BrowserNewBrowserCDPSessionParams, progress: Progress): Promise<channels.BrowserNewBrowserCDPSessionResult>;
  async startTracing(params: channels.BrowserStartTracingParams, progress: Progress): Promise<channels.BrowserStartTracingResult>;
  async stopTracing(params: channels.BrowserStopTracingParams, progress: Progress): Promise<channels.BrowserStopTracingResult>;
}

Import

import { BrowserDispatcher } from '../server/dispatchers/browserDispatcher';

I/O Contract

Inputs

Name	Type	Required	Description
scope	BrowserTypeDispatcher	Yes	Parent browser type dispatcher scope
browser	Browser	Yes	The server-side browser instance to expose
options	BrowserDispatcherOptions	No	Options for ignoreStopAndKill and isolateContexts

Outputs

Name	Type	Description
context	BrowserContextDispatcher	Dispatcher for a newly created browser context
(events)	context, close	Events dispatched to the client

Usage Examples

import { BrowserDispatcher } from '../server/dispatchers/browserDispatcher';

const browserDispatcher = new BrowserDispatcher(browserTypeScope, browser, { isolateContexts: true });
const { context } = await browserDispatcher.newContext({ viewport: { width: 1280, height: 720 } }, progress);

Related Pages

• Environment:Microsoft_Playwright_Node_Runtime_Environment