fix(config): allow specifying user data dir in config (#342)

Fixes https://github.com/microsoft/playwright-mcp/issues/340

src/config.ts

@@ -42,7 +42,6 @@ export type CLIOptions = {
 const defaultConfig: Config = {
   browser: {
     browserName: 'chromium',
-    userDataDir: os.tmpdir(),
     launchOptions: {
       channel: 'chrome',
       headless: os.platform() === 'linux' && !process.env.DISPLAY,
@@ -100,7 +99,7 @@ export async function configFromCLIOptions(cliOptions: CLIOptions): Promise<Conf
   return {
     browser: {
       browserName,
-      userDataDir: cliOptions.userDataDir ?? await createUserDataDir({ browserName, channel }),
+      userDataDir: cliOptions.userDataDir,
       launchOptions,
       contextOptions,
       cdpEndpoint: cliOptions.cdpEndpoint,
@@ -137,21 +136,6 @@ async function loadConfig(configFile: string | undefined): Promise<Config> {
   }
 }
 
-async function createUserDataDir(options: { browserName: 'chromium' | 'firefox' | 'webkit', channel: string | undefined }) {
-  let cacheDirectory: string;
-  if (process.platform === 'linux')
-    cacheDirectory = process.env.XDG_CACHE_HOME || path.join(os.homedir(), '.cache');
-  else if (process.platform === 'darwin')
-    cacheDirectory = path.join(os.homedir(), 'Library', 'Caches');
-  else if (process.platform === 'win32')
-    cacheDirectory = process.env.LOCALAPPDATA || path.join(os.homedir(), 'AppData', 'Local');
-  else
-    throw new Error('Unsupported platform: ' + process.platform);
-  const result = path.join(cacheDirectory, 'ms-playwright', `mcp-${options.channel ?? options.browserName}-profile`);
-  await fs.promises.mkdir(result, { recursive: true });
-  return result;
-}
-
 export async function outputFile(config: Config, name: string): Promise<string> {
   const result = config.outputDir ?? os.tmpdir();
   await fs.promises.mkdir(result, { recursive: true });

src/context.ts

@@ -14,6 +14,10 @@
  * limitations under the License.
  */
 
+import fs from 'node:fs';
+import os from 'node:os';
+import path from 'node:path';
+
 import * as playwright from 'playwright';
 
 import { waitForCompletion } from './tools/utils.js';
@@ -333,8 +337,10 @@ ${code.join('\n')}
 
 async function launchPersistentContext(browserConfig: Config['browser']): Promise<playwright.BrowserContext> {
   try {
-    const browserType = browserConfig?.browserName ? playwright[browserConfig.browserName] : playwright.chromium;
-    return await browserType.launchPersistentContext(browserConfig?.userDataDir || '', { ...browserConfig?.launchOptions, ...browserConfig?.contextOptions });
+    const browserName = browserConfig?.browserName ?? 'chromium';
+    const userDataDir = browserConfig?.userDataDir ?? await createUserDataDir({ ...browserConfig, browserName });
+    const browserType = playwright[browserName];
+    return await browserType.launchPersistentContext(userDataDir, { ...browserConfig?.launchOptions, ...browserConfig?.contextOptions });
   } catch (error: any) {
     if (error.message.includes('Executable doesn\'t exist'))
       throw new Error(`Browser specified in your config is not installed. Either install it (likely) or change the config.`);
@@ -342,6 +348,21 @@ async function launchPersistentContext(browserConfig: Config['browser']): Promis
   }
 }
 
+async function createUserDataDir(browserConfig: Config['browser']) {
+  let cacheDirectory: string;
+  if (process.platform === 'linux')
+    cacheDirectory = process.env.XDG_CACHE_HOME || path.join(os.homedir(), '.cache');
+  else if (process.platform === 'darwin')
+    cacheDirectory = path.join(os.homedir(), 'Library', 'Caches');
+  else if (process.platform === 'win32')
+    cacheDirectory = process.env.LOCALAPPDATA || path.join(os.homedir(), 'AppData', 'Local');
+  else
+    throw new Error('Unsupported platform: ' + process.platform);
+  const result = path.join(cacheDirectory, 'ms-playwright', `mcp-${browserConfig?.launchOptions.channel ?? browserConfig?.browserName}-profile`);
+  await fs.promises.mkdir(result, { recursive: true });
+  return result;
+}
+
 export async function generateLocator(locator: playwright.Locator): Promise<string> {
   return (locator as any)._generateLocatorString();
 }

tests/config.spec.ts

@@ -0,0 +1,41 @@
+/**
+ * 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 fs from 'node:fs';
+
+import { Config } from '../config.js';
+import { test, expect } from './fixtures.js';
+
+test('config user data dir', async ({ startClient, mcpBrowser }, testInfo) => {
+  const config: Config = {
+    browser: {
+      userDataDir: testInfo.outputPath('user-data-dir'),
+    },
+  };
+  const configPath = testInfo.outputPath('config.json');
+  await fs.promises.writeFile(configPath, JSON.stringify(config, null, 2));
+
+  const client = await startClient({ args: ['--config', configPath] });
+  expect(await client.callTool({
+    name: 'browser_navigate',
+    arguments: {
+      url: 'data:text/html,<html><body>Hello, world!</body></html>',
+    },
+  })).toContainTextContent(`Hello, world!`);
+
+  const files = await fs.promises.readdir(config.browser!.userDataDir!);
+  expect(files.length).toBeGreaterThan(0);
+});