api-media-handler-spec.ts

import { expect } from 'chai';
import { BrowserWindow, session, desktopCapturer } from 'electron/main';
import { closeAllWindows } from './lib/window-helpers';
import * as http from 'node:http';
import { ifit, listen } from './lib/spec-helpers';

describe('setDisplayMediaRequestHandler', () => {
  afterEach(closeAllWindows);
  // These tests are done on an http server because navigator.userAgentData
  // requires a secure context.
  let server: http.Server;
  let serverUrl: string;
  before(async () => {
    server = http.createServer((req, res) => {
      res.setHeader('Content-Type', 'text/html');
      res.end('');
    });
    serverUrl = (await listen(server)).url;
  });
  after(() => {
    server.close();
  });

  ifit(process.platform !== 'darwin')('works when calling getDisplayMedia', async function () {
    if ((await desktopCapturer.getSources({ types: ['screen'] })).length === 0) {
      return this.skip();
    }
    const ses = session.fromPartition('' + Math.random());
    let requestHandlerCalled = false;
    let mediaRequest: any = null;
    ses.setDisplayMediaRequestHandler((request, callback) => {
      requestHandlerCalled = true;
      mediaRequest = request;
      desktopCapturer.getSources({ types: ['screen'] }).then((sources) => {
        // Grant access to the first screen found.
        const { id, name } = sources[0];
        callback({
          video: { id, name }
          // TODO: 'loopback' and 'loopbackWithMute' are currently only supported on Windows.
          // audio: { id: 'loopback', name: 'System Audio' }
        });
      });
    });
    const w = new BrowserWindow({ show: false, webPreferences: { session: ses } });
    await w.loadURL(serverUrl);
    const { ok, message } = await w.webContents.executeJavaScript(`
      navigator.mediaDevices.getDisplayMedia({
        video: true,
        audio: false,
      }).then(x => ({ok: x instanceof MediaStream}), e => ({ok: false, message: e.message}))
    `, true);
    expect(requestHandlerCalled).to.be.true();
    expect(mediaRequest.videoRequested).to.be.true();
    expect(mediaRequest.audioRequested).to.be.false();
    expect(ok).to.be.true(message);
  });

  it('does not crash when using a bogus ID', async () => {
    const ses = session.fromPartition('' + Math.random());
    let requestHandlerCalled = false;
    ses.setDisplayMediaRequestHandler((request, callback) => {
      requestHandlerCalled = true;
      callback({
        video: { id: 'bogus', name: 'whatever' }
      });
    });
    const w = new BrowserWindow({ show: false, webPreferences: { session: ses } });
    await w.loadURL(serverUrl);
    const { ok, message } = await w.webContents.executeJavaScript(`
      navigator.mediaDevices.getDisplayMedia({
        video: true,
        audio: true,
      }).then(x => ({ok: x instanceof MediaStream}), e => ({ok: false, message: e.message}))
    `, true);
    expect(requestHandlerCalled).to.be.true();
    expect(ok).to.be.false();
    expect(message).to.equal('Could not start video source');
  });

  it('successfully returns a capture handle', async () => {
    let w: BrowserWindow | null = null;
    const ses = session.fromPartition('' + Math.random());
    let requestHandlerCalled = false;
    let mediaRequest: any = null;
    ses.setDisplayMediaRequestHandler((request, callback) => {
      requestHandlerCalled = true;
      mediaRequest = request;
      callback({ video: w?.webContents.mainFrame });
    });

    w = new BrowserWindow({ show: false, webPreferences: { session: ses } });
    await w.loadURL(serverUrl);

    const { ok, handleID, captureHandle, message } = await w.webContents.executeJavaScript(`
      const handleID = crypto.randomUUID();
      navigator.mediaDevices.setCaptureHandleConfig({
        handle: handleID,
        exposeOrigin: true,
        permittedOrigins: ["*"],
      });

      navigator.mediaDevices.getDisplayMedia({
        video: true,
        audio: false
      }).then(stream => {
        const [videoTrack] = stream.getVideoTracks();
        const captureHandle = videoTrack.getCaptureHandle();
        return { ok: true, handleID, captureHandle, message: null }
      }, e => ({ ok: false, message: e.message }))
    `, true);

    expect(requestHandlerCalled).to.be.true();
    expect(mediaRequest.videoRequested).to.be.true();
    expect(mediaRequest.audioRequested).to.be.false();
    expect(ok).to.be.true();
    expect(captureHandle.handle).to.be.a('string');
    expect(handleID).to.eq(captureHandle.handle);
    expect(message).to.be.null();
  });

  it('does not crash when providing only audio for a video request', async () => {
    const ses = session.fromPartition('' + Math.random());
    let requestHandlerCalled = false;
    let callbackError: any;
    ses.setDisplayMediaRequestHandler((request, callback) => {
      requestHandlerCalled = true;
      try {
        callback({
          audio: 'loopback'
        });
      } catch (e) {
        callbackError = e;
      }
    });
    const w = new BrowserWindow({ show: false, webPreferences: { session: ses } });
    await w.loadURL(serverUrl);
    const { ok } = await w.webContents.executeJavaScript(`
      navigator.mediaDevices.getDisplayMedia({
        video: true,
      }).then(x => ({ok: x instanceof MediaStream}), e => ({ok: false, message: e.message}))
    `, true);
    expect(requestHandlerCalled).to.be.true();
    expect(ok).to.be.false();
    expect(callbackError?.message).to.equal('Video was requested, but no video stream was provided');
  });

  it('does not crash when providing only an audio stream for an audio+video request', async () => {
    const ses = session.fromPartition('' + Math.random());
    let requestHandlerCalled = false;
    let callbackError: any;
    ses.setDisplayMediaRequestHandler((request, callback) => {
      requestHandlerCalled = true;
      try {
        callback({
          audio: 'loopback'
        });
      } catch (e) {
        callbackError = e;
      }
    });
    const w = new BrowserWindow({ show: false, webPreferences: { session: ses } });
    await w.loadURL(serverUrl);
    const { ok } = await w.webContents.executeJavaScript(`
      navigator.mediaDevices.getDisplayMedia({
        video: true,
        audio: true,
      }).then(x => ({ok: x instanceof MediaStream}), e => ({ok: false, message: e.message}))
    `, true);
    expect(requestHandlerCalled).to.be.true();
    expect(ok).to.be.false();
    expect(callbackError?.message).to.equal('Video was requested, but no video stream was provided');
  });

  it('does not crash when providing a non-loopback audio stream', async () => {
    const ses = session.fromPartition('' + Math.random());
    let requestHandlerCalled = false;
    ses.setDisplayMediaRequestHandler((request, callback) => {
      requestHandlerCalled = true;
      callback({
        video: w.webContents.mainFrame,
        audio: 'default' as any
      });
    });
    const w = new BrowserWindow({ show: false, webPreferences: { session: ses } });
    await w.loadURL(serverUrl);
    const { ok } = await w.webContents.executeJavaScript(`
      navigator.mediaDevices.getDisplayMedia({
        video: true,
        audio: true,
      }).then(x => ({ok: x instanceof MediaStream}), e => ({ok: false, message: e.message}))
    `, true);
    expect(requestHandlerCalled).to.be.true();
    expect(ok).to.be.true();
  });

  it('does not crash when providing no streams', async () => {
    const ses = session.fromPartition('' + Math.random());
    let requestHandlerCalled = false;
    let callbackError: any;
    ses.setDisplayMediaRequestHandler((request, callback) => {
      requestHandlerCalled = true;
      try {
        callback({});
      } catch (e) {
        callbackError = e;
      }
    });
    const w = new BrowserWindow({ show: false, webPreferences: { session: ses } });
    await w.loadURL(serverUrl);
    const { ok } = await w.webContents.executeJavaScript(`
      navigator.mediaDevices.getDisplayMedia({
        video: true,
        audio: true,
      }).then(x => ({ok: x instanceof MediaStream}), e => ({ok: false, message: e.message}))
    `, true);
    expect(requestHandlerCalled).to.be.true();
    expect(ok).to.be.false();
    expect(callbackError.message).to.equal('Video was requested, but no video stream was provided');
  });

  it('does not crash when using a bogus web-contents-media-stream:// ID', async () => {
    const ses = session.fromPartition('' + Math.random());
    let requestHandlerCalled = false;
    ses.setDisplayMediaRequestHandler((request, callback) => {
      requestHandlerCalled = true;
      callback({
        video: { id: 'web-contents-media-stream://9999:9999', name: 'whatever' }
      });
    });
    const w = new BrowserWindow({ show: false, webPreferences: { session: ses } });
    await w.loadURL(serverUrl);
    const { ok } = await w.webContents.executeJavaScript(`
      navigator.mediaDevices.getDisplayMedia({
        video: true,
        audio: true,
      }).then(x => ({ok: x instanceof MediaStream}), e => ({ok: false, message: e.message}))
    `, true);
    expect(requestHandlerCalled).to.be.true();
    // This is a little surprising... apparently chrome will generate a stream
    // for this non-existent web contents?
    expect(ok).to.be.true();
  });

  it('is not called when calling getUserMedia', async () => {
    const ses = session.fromPartition('' + Math.random());
    ses.setDisplayMediaRequestHandler(() => {
      throw new Error('bad');
    });
    const w = new BrowserWindow({ show: false, webPreferences: { session: ses } });
    await w.loadURL(serverUrl);
    const { ok, message } = await w.webContents.executeJavaScript(`
      navigator.mediaDevices.getUserMedia({
        video: true,
        audio: true,
      }).then(x => ({ok: x instanceof MediaStream}), e => ({ok: false, message: e.message}))
    `);
    expect(ok).to.be.true(message);
  });

  it('works when calling getDisplayMedia with preferCurrentTab', async () => {
    const ses = session.fromPartition('' + Math.random());
    let requestHandlerCalled = false;
    ses.setDisplayMediaRequestHandler((request, callback) => {
      requestHandlerCalled = true;
      callback({ video: w.webContents.mainFrame });
    });
    const w = new BrowserWindow({ show: false, webPreferences: { session: ses } });
    await w.loadURL(serverUrl);
    const { ok, message } = await w.webContents.executeJavaScript(`
      navigator.mediaDevices.getDisplayMedia({
        preferCurrentTab: true,
        video: true,
        audio: true,
      }).then(x => ({ok: x instanceof MediaStream}), e => ({ok: false, message: e.message}))
    `, true);
    expect(requestHandlerCalled).to.be.true();
    expect(ok).to.be.true(message);
  });

  it('returns a MediaStream with BrowserCaptureMediaStreamTrack when the current tab is selected', async () => {
    const ses = session.fromPartition('' + Math.random());
    let requestHandlerCalled = false;
    ses.setDisplayMediaRequestHandler((request, callback) => {
      requestHandlerCalled = true;
      callback({ video: w.webContents.mainFrame });
    });
    const w = new BrowserWindow({ show: false, webPreferences: { session: ses } });
    await w.loadURL(serverUrl);
    const { ok, message } = await w.webContents.executeJavaScript(`
      navigator.mediaDevices.getDisplayMedia({
        preferCurrentTab: true,
        video: true,
        audio: false,
      }).then(stream => {
        const [videoTrack] = stream.getVideoTracks();
        return { ok: videoTrack instanceof BrowserCaptureMediaStreamTrack, message: null };
      }, e => ({ok: false, message: e.message}))
    `, true);
    expect(requestHandlerCalled).to.be.true();
    expect(ok).to.be.true(message);
  });

  ifit(process.platform !== 'darwin')('can supply a screen response to preferCurrentTab', async () => {
    const ses = session.fromPartition('' + Math.random());
    let requestHandlerCalled = false;
    ses.setDisplayMediaRequestHandler(async (request, callback) => {
      requestHandlerCalled = true;
      const sources = await desktopCapturer.getSources({ types: ['screen'] });
      callback({ video: sources[0] });
    });
    const w = new BrowserWindow({ show: false, webPreferences: { session: ses } });
    await w.loadURL(serverUrl);
    const { ok, message } = await w.webContents.executeJavaScript(`
      navigator.mediaDevices.getDisplayMedia({
        preferCurrentTab: true,
        video: true,
        audio: true,
      }).then(x => ({ok: x instanceof MediaStream}), e => ({ok: false, message: e.message}))
    `, true);
    expect(requestHandlerCalled).to.be.true();
    expect(ok).to.be.true(message);
  });

  it('can supply a frame response', async () => {
    const ses = session.fromPartition('' + Math.random());
    let requestHandlerCalled = false;
    ses.setDisplayMediaRequestHandler(async (request, callback) => {
      requestHandlerCalled = true;
      callback({ video: w.webContents.mainFrame });
    });
    const w = new BrowserWindow({ show: false, webPreferences: { session: ses } });
    await w.loadURL(serverUrl);
    const { ok, message } = await w.webContents.executeJavaScript(`
      navigator.mediaDevices.getDisplayMedia({
        video: true,
      }).then(x => ({ok: x instanceof MediaStream}), e => ({ok: false, message: e.message}))
    `, true);
    expect(requestHandlerCalled).to.be.true();
    expect(ok).to.be.true(message);
  });

  it('is not called when calling legacy getUserMedia', async () => {
    const ses = session.fromPartition('' + Math.random());
    ses.setDisplayMediaRequestHandler(() => {
      throw new Error('bad');
    });
    const w = new BrowserWindow({ show: false, webPreferences: { session: ses } });
    await w.loadURL(serverUrl);
    const { ok, message } = await w.webContents.executeJavaScript(`
      new Promise((resolve, reject) => navigator.getUserMedia({
        video: true,
        audio: true,
      }, x => resolve({ok: x instanceof MediaStream}), e => reject({ok: false, message: e.message})))
    `);
    expect(ok).to.be.true(message);
  });

  it('is not called when calling legacy getUserMedia with desktop capture constraint', async () => {
    const ses = session.fromPartition('' + Math.random());
    ses.setDisplayMediaRequestHandler(() => {
      throw new Error('bad');
    });
    const w = new BrowserWindow({ show: false, webPreferences: { session: ses } });
    await w.loadURL(serverUrl);
    const { ok, message } = await w.webContents.executeJavaScript(`
      new Promise((resolve, reject) => navigator.getUserMedia({
        video: {
          mandatory: {
            chromeMediaSource: 'desktop'
          }
        },
      }, x => resolve({ok: x instanceof MediaStream}), e => reject({ok: false, message: e.message})))
    `);
    expect(ok).to.be.true(message);
  });

  it('works when calling getUserMedia without a media request handler', async () => {
    const w = new BrowserWindow({ show: false });
    await w.loadURL(serverUrl);
    const { ok, message } = await w.webContents.executeJavaScript(`
      navigator.mediaDevices.getUserMedia({
        video: true,
        audio: true,
      }).then(x => ({ok: x instanceof MediaStream}), e => ({ok: false, message: e.message}))
    `);
    expect(ok).to.be.true(message);
  });

  it('works when calling legacy getUserMedia without a media request handler', async () => {
    const w = new BrowserWindow({ show: false });
    await w.loadURL(serverUrl);
    const { ok, message } = await w.webContents.executeJavaScript(`
      new Promise((resolve, reject) => navigator.getUserMedia({
        video: true,
        audio: true,
      }, x => resolve({ok: x instanceof MediaStream}), e => reject({ok: false, message: e.message})))
    `);
    expect(ok).to.be.true(message);
  });

  it('can remove a displayMediaRequestHandler', async () => {
    const ses = session.fromPartition('' + Math.random());

    ses.setDisplayMediaRequestHandler(() => {
      throw new Error('bad');
    });
    ses.setDisplayMediaRequestHandler(null);
    const w = new BrowserWindow({ show: false, webPreferences: { session: ses } });
    await w.loadURL(serverUrl);
    const { ok, message } = await w.webContents.executeJavaScript(`
      navigator.mediaDevices.getDisplayMedia({
        video: true,
      }).then(x => ({ok: x instanceof MediaStream}), e => ({ok: false, message: e.message}))
    `, true);
    expect(ok).to.be.false();
    expect(message).to.equal('Not supported');
  });
});