chore(extension): find installed chrome

Author: yury-s

src/extension/browserRegistry.ts

@@ -0,0 +1,60 @@
+/**
+ * Copyright (c) Microsoft Corporation.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+import path from 'path';
+import fs from 'fs';
+import debug from 'debug';
+
+const debugLogger = debug('pw:mcp:relay:browser');
+
+export function findChromeExecutable() {
+  const lookAt: Record<'linux' | 'darwin' | 'win32', string> = {
+    'linux': '/opt/google/chrome/chrome',
+    'darwin': '/Applications/Google Chrome.app/Contents/MacOS/Google Chrome',
+    'win32': `\\Google\\Chrome\\Application\\chrome.exe`,
+  };
+  const suffix = lookAt[process.platform as 'linux' | 'darwin' | 'win32'];
+  if (!suffix)
+    throw new Error(`Chrome distribution is not supported on ${process.platform}`);
+  const prefixes = (process.platform === 'win32' ? [
+    process.env.LOCALAPPDATA,
+    process.env.PROGRAMFILES,
+    process.env['PROGRAMFILES(X86)'],
+    // In some cases there is no PROGRAMFILES/(86) env var set but HOMEDRIVE is set.
+    process.env.HOMEDRIVE + '\\Program Files',
+    process.env.HOMEDRIVE + '\\Program Files (x86)',
+  ].filter(Boolean) : ['']) as string[];
+
+  for (const prefix of prefixes) {
+    const executablePath = path.join(prefix, suffix);
+    debugLogger(`Checking ${executablePath}`);
+    if (canAccessFile(executablePath))
+      return executablePath;
+  }
+  throw new Error(`Chrome distribution not found. Make sure it is installed at a standard location.`);
+}
+
+function canAccessFile(file: string) {
+  if (!file)
+    return false;
+
+  try {
+    fs.accessSync(file);
+    return true;
+  } catch (e) {
+    return false;
+  }
+}

src/extension/cdpRelay.ts

@@ -26,11 +26,11 @@ import { WebSocket, WebSocketServer } from 'ws';
 import type websocket from 'ws';
 import http from 'node:http';
 import debug from 'debug';
-import { promisify } from 'node:util';
-import { exec } from 'node:child_process';
 import { httpAddressToString, startHttpServer } from '../transport.js';
 import { BrowserContextFactory } from '../browserContextFactory.js';
 import { Browser, chromium, type BrowserContext } from 'playwright';
+import { spawnAsync } from './spawnAsync.js';
+import { findChromeExecutable } from './browserRegistry.js';
 
 const debugLogger = debug('pw:mcp:relay');
 
@@ -88,10 +88,13 @@ export class CDPRelayServer {
   }
 
   async ensureExtensionConnectionForMCPContext(clientInfo: { name: string, version: string }) {
+    debugLogger('Ensuring extension connection for MCP context');
     if (this._extensionConnection)
       return;
     await this._connectBrowser(clientInfo);
+    debugLogger('Waiting for incoming extension connection');
     await this._extensionConnectionPromise;
+    debugLogger('Extension connection established');
   }
 
   private async _connectBrowser(clientInfo: { name: string, version: string }) {
@@ -101,12 +104,10 @@ export class CDPRelayServer {
     url.searchParams.set('mcpRelayUrl', mcpRelayEndpoint);
     url.searchParams.set('client', JSON.stringify(clientInfo));
     const href = url.toString();
-    const command = `'/Applications/Google Chrome.app/Contents/MacOS/Google Chrome' '${href}'`;
-    try {
-      await promisify(exec)(command);
-    } catch (err) {
+    const chromeExecutablePath = findChromeExecutable();
+    void spawnAsync(chromeExecutablePath, [href], { detached: true, shell: false }).catch(err => {
       debugLogger('Failed to run command:', err);
-    }
+    });
   }
 
   stop(): void {
@@ -332,7 +333,7 @@ class ExtensionConnection {
 
   async send(method: string, params?: any, sessionId?: string): Promise<any> {
     if (this._ws.readyState !== WebSocket.OPEN)
-      throw new Error('WebSocket closed');
+      throw new Error(`Unexpected WebSocket state: ${this._ws.readyState}`);
     const id = ++this._lastId;
     this._ws.send(JSON.stringify({ id, method, params, sessionId }));
     return new Promise((resolve, reject) => {

src/extension/spawnAsync.ts

@@ -0,0 +1,34 @@
+/**
+ * Copyright (c) Microsoft Corporation.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+import { spawn } from 'child_process';
+
+import type { SpawnOptions } from 'child_process';
+
+export function spawnAsync(cmd: string, args: string[], options: SpawnOptions = {}): Promise<{stdout: string, stderr: string, code: number | null, error?: Error}> {
+  const process = spawn(cmd, args, { windowsHide: true, ...options });
+
+  return new Promise(resolve => {
+    let stdout = '';
+    let stderr = '';
+    if (process.stdout)
+      process.stdout.on('data', data => stdout += data.toString());
+    if (process.stderr)
+      process.stderr.on('data', data => stderr += data.toString());
+    process.on('close', code => resolve({ stdout, stderr, code }));
+    process.on('error', error => resolve({ stdout, stderr, code: 0, error }));
+  });
+}