perf: use CDP to find open DevTools pages. (#1150)

This should reduce the flakiness and issue with finding open DevTools
tabs for the corresponding pages.
Currently we do multiple loops over all the targets, so this should have
a nice performance improvement when multiple pages are opened.

src/DevtoolsUtils.ts

@@ -15,61 +15,6 @@ import type {
   Target as PuppeteerTarget,
 } from './third_party/index.js';
 
-export function extractUrlLikeFromDevToolsTitle(
-  title: string,
-): string | undefined {
-  const match = title.match(new RegExp(`DevTools - (.*)`));
-  return match?.[1] ?? undefined;
-}
-
-export function urlsEqual(url1: string, url2: string): boolean {
-  const normalizedUrl1 = normalizeUrl(url1);
-  const normalizedUrl2 = normalizeUrl(url2);
-  return normalizedUrl1 === normalizedUrl2;
-}
-
-/**
- * For the sake of the MCP server, when we determine if two URLs are equal we
- * remove some parts:
- *
- * 1. We do not care about the protocol.
- * 2. We do not care about trailing slashes.
- * 3. We do not care about "www".
- * 4. We ignore the hash parts.
- *
- * For example, if the user types "record a trace on foo.com", we would want to
- * match a tab in the connected Chrome instance that is showing "www.foo.com/"
- */
-function normalizeUrl(url: string): string {
-  let result = url.trim();
-
-  // Remove protocols
-  if (result.startsWith('https://')) {
-    result = result.slice(8);
-  } else if (result.startsWith('http://')) {
-    result = result.slice(7);
-  }
-
-  // Remove 'www.'. This ensures that we find the right URL regardless of if the user adds `www` or not.
-  if (result.startsWith('www.')) {
-    result = result.slice(4);
-  }
-
-  // We use target URLs to locate DevTools but those often do
-  // no include hash.
-  const hashIdx = result.lastIndexOf('#');
-  if (hashIdx !== -1) {
-    result = result.slice(0, hashIdx);
-  }
-
-  // Remove trailing slash
-  if (result.endsWith('/')) {
-    result = result.slice(0, -1);
-  }
-
-  return result;
-}
-
 /**
  * A mock implementation of an issues manager that only implements the methods
  * that are actually used by the IssuesAggregator

src/McpContext.ts

@@ -8,11 +8,7 @@ import fs from 'node:fs/promises';
 import path from 'node:path';
 
 import type {TargetUniverse} from './DevtoolsUtils.js';
-import {
-  extractUrlLikeFromDevToolsTitle,
-  UniverseManager,
-  urlsEqual,
-} from './DevtoolsUtils.js';
+import {UniverseManager} from './DevtoolsUtils.js';
 import {McpPage} from './McpPage.js';
 import type {ListenerMap, UncaughtError} from './PageCollector.js';
 import {NetworkCollector, ConsoleCollector} from './PageCollector.js';
@@ -653,37 +649,21 @@ export class McpContext implements Context {
   async detectOpenDevToolsWindows() {
     this.logger('Detecting open DevTools windows');
     const {pages} = await this.#getAllPages();
-    // Clear all devToolsPage references before re-detecting.
-    for (const mcpPage of this.#mcpPages.values()) {
-      mcpPage.devToolsPage = undefined;
-    }
-    for (const devToolsPage of pages) {
-      if (devToolsPage.url().startsWith('devtools://')) {
-        try {
-          this.logger('Calling getTargetInfo for ' + devToolsPage.url());
-          const data = await devToolsPage
-            // @ts-expect-error no types for _client().
-            ._client()
-            .send('Target.getTargetInfo');
-          const devtoolsPageTitle = data.targetInfo.title;
-          const urlLike = extractUrlLikeFromDevToolsTitle(devtoolsPageTitle);
-          if (!urlLike) {
-            continue;
-          }
-          // TODO: lookup without a loop.
-          for (const page of this.#pages) {
-            if (urlsEqual(page.url(), urlLike)) {
-              const mcpPage = this.#mcpPages.get(page);
-              if (mcpPage) {
-                mcpPage.devToolsPage = devToolsPage;
-              }
-            }
-          }
-        } catch (error) {
-          this.logger('Issue occurred while trying to find DevTools', error);
+
+    await Promise.all(
+      pages.map(async page => {
+        const mcpPage = this.#mcpPages.get(page);
+        if (!mcpPage) {
+          return;
         }
-      }
-    }
+
+        if (await page.hasDevTools()) {
+          mcpPage.devToolsPage = await page.openDevTools();
+        } else {
+          mcpPage.devToolsPage = undefined;
+        }
+      }),
+    );
   }
 
   getExtensionServiceWorkers(): ExtensionServiceWorker[] {

tests/DevtoolsUtils.test.ts

@@ -9,11 +9,7 @@ import {afterEach, describe, it} from 'node:test';
 
 import sinon from 'sinon';
 
-import {
-  extractUrlLikeFromDevToolsTitle,
-  urlsEqual,
-  UniverseManager,
-} from '../src/DevtoolsUtils.js';
+import {UniverseManager} from '../src/DevtoolsUtils.js';
 import {DevTools} from '../src/third_party/index.js';
 import type {Browser, Target} from '../src/third_party/index.js';
 
@@ -24,76 +20,6 @@ import {
   withBrowser,
 } from './utils.js';
 
-describe('extractUrlFromDevToolsTitle', () => {
-  it('deals with no trailing /', () => {
-    assert.strictEqual(
-      extractUrlLikeFromDevToolsTitle('DevTools - example.com'),
-      'example.com',
-    );
-  });
-  it('deals with a trailing /', () => {
-    assert.strictEqual(
-      extractUrlLikeFromDevToolsTitle('DevTools - example.com/'),
-      'example.com/',
-    );
-  });
-  it('deals with www', () => {
-    assert.strictEqual(
-      extractUrlLikeFromDevToolsTitle('DevTools - www.example.com/'),
-      'www.example.com/',
-    );
-  });
-  it('deals with complex url', () => {
-    assert.strictEqual(
-      extractUrlLikeFromDevToolsTitle(
-        'DevTools - www.example.com/path.html?a=b#3',
-      ),
-      'www.example.com/path.html?a=b#3',
-    );
-  });
-});
-
-describe('urlsEqual', () => {
-  it('ignores trailing slashes', () => {
-    assert.strictEqual(
-      urlsEqual('https://google.com/', 'https://google.com'),
-      true,
-    );
-  });
-
-  it('ignores www', () => {
-    assert.strictEqual(
-      urlsEqual('https://google.com/', 'https://www.google.com'),
-      true,
-    );
-  });
-
-  it('ignores protocols', () => {
-    assert.strictEqual(
-      urlsEqual('https://google.com/', 'http://www.google.com'),
-      true,
-    );
-  });
-
-  it('does not ignore other subdomains', () => {
-    assert.strictEqual(
-      urlsEqual('https://google.com/', 'https://photos.google.com'),
-      false,
-    );
-  });
-
-  it('ignores hash', () => {
-    assert.strictEqual(
-      urlsEqual('https://google.com/#', 'http://www.google.com'),
-      true,
-    );
-    assert.strictEqual(
-      urlsEqual('https://google.com/#21', 'http://www.google.com#12'),
-      true,
-    );
-  });
-});
-
 describe('UniverseManager', () => {
   afterEach(() => {
     sinon.restore();