Inspector Proxy

/**
 * Main Inspector Proxy class that manages device connections and debugger sessions
 * @param projectRoot - Root of the project used for relative to absolute source path conversion
 */
class InspectorProxy {
  constructor(projectRoot: string);
  
  /**
   * Process HTTP request sent to server
   * Handles /json, /json/list, and /json/version endpoints
   * @param request - Incoming HTTP request
   * @param response - HTTP response object
   * @param next - Next middleware function
   */
  processRequest(
    request: IncomingMessage,
    response: ServerResponse,
    next: (?Error) => mixed
  ): void;
  
  /**
   * Adds websocket listeners to the provided HTTP/HTTPS server
   * @param serverOrBaseUrl - HTTP/HTTPS server instance or base URL string
   * @returns Object mapping WebSocket paths to WebSocket.Server instances
   */
  createWebSocketListeners(
    serverOrBaseUrl: HttpServer | HttpsServer | string
  ): { [path: string]: WS.Server };
}

const { InspectorProxy } = require("metro-inspector-proxy");
const http = require("http");
const connect = require("connect");

// Create inspector proxy instance
const inspectorProxy = new InspectorProxy("/Users/dev/MyReactNativeApp");

// Set up HTTP middleware
const app = connect();
app.use(inspectorProxy.processRequest.bind(inspectorProxy));

// Create HTTP server
const httpServer = http.createServer(app);
httpServer.listen(8081, "127.0.0.1", () => {
  console.log("Inspector proxy server running on port 8081");
  
  // Set up WebSocket endpoints
  const websocketEndpoints = inspectorProxy.createWebSocketListeners(httpServer);
  
  // Handle WebSocket upgrades
  httpServer.on("upgrade", (request, socket, head) => {
    const { pathname } = require("url").parse(request.url);
    if (pathname && websocketEndpoints[pathname]) {
      websocketEndpoints[pathname].handleUpgrade(request, socket, head, (ws) => {
        websocketEndpoints[pathname].emit("connection", ws, request);
      });
    } else {
      socket.destroy();
    }
  });
});

/**
 * Runs new HTTP Server and attaches Inspector Proxy to it
 * @param port - Port number to listen on
 * @param projectRoot - Root directory of the project
 */
function runInspectorProxy(port: number, projectRoot: string): void;

const { runInspectorProxy } = require("metro-inspector-proxy");

// Start inspector proxy on port 8081 with project root
runInspectorProxy(8081, "/Users/dev/MyReactNativeApp");

// Server automatically handles:
// - HTTP endpoints: /json, /json/list, /json/version
// - WebSocket endpoints: /inspector/device, /inspector/debug
// - Device connection management
// - Debugger session management

[
  {
    "id": "device1-page1",
    "description": "MyApp",
    "title": "React Native",
    "faviconUrl": "https://reactjs.org/favicon.ico",
    "devtoolsFrontendUrl": "devtools://devtools/bundled/js_app.html?experiments=true&v8only=true&ws=localhost:8081/inspector/debug?device=device1&page=page1",
    "type": "node",
    "webSocketDebuggerUrl": "ws://localhost:8081/inspector/debug?device=device1&page=page1",
    "vm": "Hermes",
    "deviceName": "iPhone Simulator"
  }
]

{
  "Browser": "Mobile JavaScript",
  "Protocol-Version": "1.1"
}

// WebSocket endpoint paths
const WS_DEVICE_URL = "/inspector/device";
const WS_DEBUGGER_URL = "/inspector/debug";

// HTTP endpoint paths
const PAGES_LIST_JSON_URL = "/json";
const PAGES_LIST_JSON_URL_2 = "/json/list";
const PAGES_LIST_JSON_VERSION_URL = "/json/version";

// Configuration constants
const PAGES_POLLING_INTERVAL = 1000; // milliseconds - device page polling frequency
const INTERNAL_ERROR_CODE = 1011;    // WebSocket error code for internal errors

// Additional constants
const REACT_NATIVE_RELOADABLE_PAGE_ID = "-1"; // Special page ID for reloadable React Native debugging
const EMULATOR_LOCALHOST_ADDRESSES = ["10.0.2.2", "10.0.3.2"]; // Android emulator addresses
const FILE_PREFIX = "file://"; // Prefix added to alphanumeric script IDs for Chrome DevTools compatibility