Extension New - Rewritten CDP Relay Server

Clean, simple rewrite of the CDP relay server using Hono WebSocket.

Architecture

The relay server acts as a bridge between:

Playwright (connects via /cdp) - Controls the browser
Chrome Extension (connects via /extension) - Provides chrome.debugger access

Message Flow

Playwright → /cdp → Router → /extension → Extension → chrome.debugger → Tab
Tab → chrome.debugger → Extension → /extension → /cdp → Playwright

Implementation

Everything inlined in one file - No abstraction layers, just straightforward code.

Files

relay-server.ts - Single file with everything:

Two WebSocket endpoints (/cdp and /extension)
Connection lifecycle management
CDP command routing (Browser., Target., etc)
Extension request/response handling
Target registry (simple Map)
All message forwarding logic

protocol.ts - Message type definitions

index.ts - Exports example.ts - Usage example

Key Improvements

Simpler Code:

Everything in one place
No helper functions or modules
Clear linear flow
All state as local variables

Better Logging:

Only logs connection events, CDP messages, and errors
No verbose debug noise

Clean API:

const server = await startRelayServer({ port: 9988 })

// Returns:
// {
//   cdpEndpoint: 'ws://localhost:9988/cdp',
//   extensionEndpoint: 'ws://localhost:9988/extension',
//   close: () => void
// }

// Cleanup:
server.close()

Usage

import { startRelayServer } from './relay-server.js'

const server = await startRelayServer({ port: 9988 })

console.log('Extension endpoint:', server.extensionEndpoint)
console.log('CDP endpoint:', server.cdpEndpoint)

// Later:
server.close()

Running Example

pnpm install
pnpm build
node dist/example.js