feat(workers): create workers from service workers and shared workers (#4397)

This allows users to easily evaluate javascript inside service workers and shared workers by creating a Worker object for them.

docs/api.md

@@ -304,6 +304,7 @@
   * [target.page()](#targetpage)
   * [target.type()](#targettype)
   * [target.url()](#targeturl)
+  * [target.worker()](#targetworker)
 - [class: CDPSession](#class-cdpsession)
   * [cdpSession.detach()](#cdpsessiondetach)
   * [cdpSession.send(method[, params])](#cdpsessionsendmethod-params)
@@ -3479,13 +3480,18 @@ Get the target that opened this target. Top-level targets return `null`.
 If the target is not of type `"page"` or `"background_page"`, returns `null`.
 
 #### target.type()
-- returns: <"page"|"background_page"|"service_worker"|"other"|"browser">
+- returns: <"page"|"background_page"|"service_worker"|"shared_worker"|"other"|"browser">
 
-Identifies what kind of target this is. Can be `"page"`, [`"background_page"`](https://developer.chrome.com/extensions/background_pages), `"service_worker"`, `"browser"` or `"other"`.
+Identifies what kind of target this is. Can be `"page"`, [`"background_page"`](https://developer.chrome.com/extensions/background_pages), `"service_worker"`, `"shared_worker"`, `"browser"` or `"other"`.
 
 #### target.url()
 - returns: <[string]>
 
+#### target.worker()
+- returns: <[Promise]<?[Worker]>>
+
+If the target is not of type `"service_worker"` or `"shared_worker"`, returns `null`.
+
 ### class: CDPSession
 
 * extends: [EventEmitter](https://nodejs.org/api/events.html#events_class_eventemitter)

lib/Target.js

@@ -16,6 +16,8 @@
 
 const {Events} = require('./Events');
 const {Page} = require('./Page');
+const {Worker} = require('./Worker');
+const {Connection} = require('./Connection');
 
 class Target {
   /**
@@ -36,6 +38,8 @@ class Target {
     this._screenshotTaskQueue = screenshotTaskQueue;
     /** @type {?Promise<!Puppeteer.Page>} */
     this._pagePromise = null;
+    /** @type {?Promise<!Worker>} */
+    this._workerPromise = null;
     this._initializedPromise = new Promise(fulfill => this._initializedCallback = fulfill).then(async success => {
       if (!success)
         return false;
@@ -73,6 +77,27 @@ class Target {
     return this._pagePromise;
   }
 
+  /**
+   * @return {!Promise<?Worker>}
+   */
+  async worker() {
+    if (this._targetInfo.type !== 'service_worker' && this._targetInfo.type !== 'shared_worker')
+      return null;
+    if (!this._workerPromise) {
+      this._workerPromise = this._sessionFactory().then(async client => {
+        // Top level workers have a fake page wrapping the actual worker.
+        const [targetAttached] = await Promise.all([
+          new Promise(x => client.once('Target.attachedToTarget', x)),
+          client.send('Target.setAutoAttach', {autoAttach: true, waitForDebuggerOnStart: false, flatten: true}),
+        ]);
+        const session = Connection.fromSession(client).session(targetAttached.sessionId);
+        // TODO(einbinder): Make workers send their console logs.
+        return new Worker(session, this._targetInfo.url, () => {} /* consoleAPICalled */, () => {} /* exceptionThrown */);
+      });
+    }
+    return this._workerPromise;
+  }
+
   /**
    * @return {string}
    */
@@ -81,11 +106,11 @@ class Target {
   }
 
   /**
-   * @return {"page"|"background_page"|"service_worker"|"other"|"browser"}
+   * @return {"page"|"background_page"|"service_worker"|"shared_worker"|"other"|"browser"}
    */
   type() {
     const type = this._targetInfo.type;
-    if (type === 'page' || type === 'background_page' || type === 'service_worker' || type === 'browser')
+    if (type === 'page' || type === 'background_page' || type === 'service_worker' || type === 'shared_worker' || type === 'browser')
       return type;
     return 'other';
   }

test/target.spec.js

@@ -83,6 +83,22 @@ module.exports.addTests = function({testRunner, expect, puppeteer}) {
       await page.evaluate(() => window.registrationPromise.then(registration => registration.unregister()));
       expect(await destroyedTarget).toBe(await createdTarget);
     });
+    it_fails_ffox('should create a worker from a service worker', async({page, server, context}) => {
+      await page.goto(server.PREFIX + '/serviceworkers/empty/sw.html');
+
+      const target = await context.waitForTarget(target => target.type() === 'service_worker');
+      const worker = await target.worker();
+      expect(await worker.evaluate(() => self.toString())).toBe('[object ServiceWorkerGlobalScope]');
+    });
+    it_fails_ffox('should create a worker from a shared worker', async({page, server, context}) => {
+      await page.goto(server.EMPTY_PAGE);
+      await page.evaluate(() => {
+        new SharedWorker('data:text/javascript,console.log("hi")');
+      });
+      const target = await context.waitForTarget(target => target.type() === 'shared_worker');
+      const worker = await target.worker();
+      expect(await worker.evaluate(() => self.toString())).toBe('[object SharedWorkerGlobalScope]');
+    });
     it('should report when a target url changes', async({page, server, context}) => {
       await page.goto(server.EMPTY_PAGE);
       let changedTarget = new Promise(fulfill => context.once('targetchanged', target => fulfill(target)));