feat: expose the desktopCapturer module in the main process (#23548)

build/webpack/webpack.config.base.js

@@ -46,6 +46,7 @@ const ignoredModules = []
 if (defines['ENABLE_DESKTOP_CAPTURER'] === 'false') {
   ignoredModules.push(
     '@electron/internal/browser/desktop-capturer',
+    '@electron/internal/browser/api/desktop-capturer',
     '@electron/internal/renderer/api/desktop-capturer'
   )
 }

docs/api/desktop-capturer.md

@@ -3,7 +3,7 @@
 > Access information about media sources that can be used to capture audio and
 > video from the desktop using the [`navigator.mediaDevices.getUserMedia`] API.
 
-Process: [Renderer](../glossary.md#renderer-process)
+Process: [Main](../glossary.md#main-process), [Renderer](../glossary.md#renderer-process)
 
 The following example shows how to capture video from a desktop window whose
 title is `Electron`:

filenames.auto.gni

@@ -193,6 +193,7 @@ auto_filenames = {
     "lib/browser/api/browser-window.js",
     "lib/browser/api/content-tracing.js",
     "lib/browser/api/crash-reporter.ts",
+    "lib/browser/api/desktop-capturer.ts",
     "lib/browser/api/dialog.js",
     "lib/browser/api/exports/electron.ts",
     "lib/browser/api/global-shortcut.js",

lib/browser/api/desktop-capturer.ts

@@ -0,0 +1,5 @@
+import { getSourcesImpl } from '@electron/internal/browser/desktop-capturer';
+
+export async function getSources (options: Electron.SourcesOptions) {
+  return getSourcesImpl(null, options);
+}

lib/browser/api/module-list.ts

@@ -33,6 +33,12 @@ export const browserModuleList: ElectronInternal.ModuleEntry[] = [
   { name: 'WebContentsView', loader: () => require('./web-contents-view') }
 ];
 
+if (BUILDFLAG(ENABLE_DESKTOP_CAPTURER)) {
+  browserModuleList.push(
+    { name: 'desktopCapturer', loader: () => require('./desktop-capturer') }
+  );
+}
+
 if (BUILDFLAG(ENABLE_VIEWS_API)) {
   browserModuleList.push(
     { name: 'ImageView', loader: () => require('./views/image-view') }

lib/browser/api/module-names.ts

@@ -36,6 +36,10 @@ export const browserModuleNames = [
   'WebContentsView'
 ];
 
+if (BUILDFLAG(ENABLE_DESKTOP_CAPTURER)) {
+  browserModuleNames.push('desktopCapturer');
+}
+
 if (BUILDFLAG(ENABLE_VIEWS_API)) {
   browserModuleNames.push(
     'ImageView'

lib/browser/desktop-capturer.ts

@@ -7,7 +7,28 @@ let currentlyRunning: {
   getSources: Promise<ElectronInternal.GetSourcesResult[]>;
 }[] = [];
 
-export const getSources = (event: Electron.IpcMainEvent, options: ElectronInternal.GetSourcesOptions) => {
+// |options.types| can't be empty and must be an array
+function isValid (options: Electron.SourcesOptions) {
+  const types = options ? options.types : undefined;
+  return Array.isArray(types);
+}
+
+export const getSourcesImpl = (event: Electron.IpcMainEvent | null, args: Electron.SourcesOptions) => {
+  if (!isValid(args)) throw new Error('Invalid options');
+
+  const captureWindow = args.types.includes('window');
+  const captureScreen = args.types.includes('screen');
+
+  const { thumbnailSize = { width: 150, height: 150 } } = args;
+  const { fetchWindowIcons = false } = args;
+
+  const options = {
+    captureWindow,
+    captureScreen,
+    thumbnailSize,
+    fetchWindowIcons
+  };
+
   for (const running of currentlyRunning) {
     if (deepEqual(running.options, options)) {
       // If a request is currently running for the same options
@@ -39,12 +60,14 @@ export const getSources = (event: Electron.IpcMainEvent, options: ElectronIntern
       resolve(sources);
     };
 
-    capturer.startHandling(options.captureWindow, options.captureScreen, options.thumbnailSize, options.fetchWindowIcons);
+    capturer.startHandling(captureWindow, captureScreen, thumbnailSize, fetchWindowIcons);
 
     // If the WebContents is destroyed before receiving result, just remove the
     // reference to emit and the capturer itself so that it never dispatches
     // back to the renderer
-    event.sender.once('destroyed', () => stopRunning());
+    if (event) {
+      event.sender.once('destroyed', () => stopRunning());
+    }
   });
 
   currentlyRunning.push({

lib/browser/rpc-server.js

@@ -71,7 +71,7 @@ if (BUILDFLAG(ENABLE_DESKTOP_CAPTURER)) {
       return [];
     }
 
-    return typeUtils.serialize(await desktopCapturer.getSources(event, options));
+    return typeUtils.serialize(await desktopCapturer.getSourcesImpl(event, options));
   });
 }
 

lib/renderer/api/desktop-capturer.ts

@@ -3,12 +3,6 @@ import { deserialize } from '@electron/internal/common/type-utils';
 
 const { hasSwitch } = process.electronBinding('command_line');
 
-// |options.types| can't be empty and must be an array
-function isValid (options: Electron.SourcesOptions) {
-  const types = options ? options.types : undefined;
-  return Array.isArray(types);
-}
-
 const enableStacks = hasSwitch('enable-api-filtering-logging');
 
 function getCurrentStack () {
@@ -20,20 +14,5 @@ function getCurrentStack () {
 }
 
 export async function getSources (options: Electron.SourcesOptions) {
-  if (!isValid(options)) throw new Error('Invalid options');
-
-  const captureWindow = options.types.includes('window');
-  const captureScreen = options.types.includes('screen');
-
-  const { thumbnailSize = { width: 150, height: 150 } } = options;
-  const { fetchWindowIcons = false } = options;
-
-  const sources = await ipcRendererInternal.invoke<ElectronInternal.GetSourcesResult[]>('ELECTRON_BROWSER_DESKTOP_CAPTURER_GET_SOURCES', {
-    captureWindow,
-    captureScreen,
-    thumbnailSize,
-    fetchWindowIcons
-  } as ElectronInternal.GetSourcesOptions, getCurrentStack());
-
-  return deserialize(sources);
+  return deserialize(await ipcRendererInternal.invoke('ELECTRON_BROWSER_DESKTOP_CAPTURER_GET_SOURCES', options, getCurrentStack()));
 }

spec-main/api-desktop-capturer-spec.ts

@@ -1,6 +1,6 @@
 import { expect } from 'chai';
 import { screen, BrowserWindow, SourcesOptions } from 'electron/main';
-import { desktopCapturer } from 'electron/renderer';
+import { desktopCapturer } from 'electron/common';
 import { emittedOnce } from './events-helpers';
 import { ifdescribe, ifit } from './spec-helpers';
 import { closeAllWindows } from './window-helpers';
@@ -21,55 +21,63 @@ ifdescribe(features.isDesktopCapturerEnabled() && !process.arch.includes('arm')
     `);
   };
 
-  // TODO(nornagon): figure out why this test is failing on Linux and re-enable it.
-  ifit(process.platform !== 'linux')('should return a non-empty array of sources', async () => {
-    const sources = await getSources({ types: ['window', 'screen'] });
-    expect(sources).to.be.an('array').that.is.not.empty();
-  });
+  const generateSpecs = (description: string, getSources: typeof desktopCapturer.getSources) => {
+    describe(description, () => {
+      // TODO(nornagon): figure out why this test is failing on Linux and re-enable it.
+      ifit(process.platform !== 'linux')('should return a non-empty array of sources', async () => {
+        const sources = await getSources({ types: ['window', 'screen'] });
+        expect(sources).to.be.an('array').that.is.not.empty();
+      });
 
-  it('throws an error for invalid options', async () => {
-    const promise = getSources(['window', 'screen'] as any);
-    await expect(promise).to.be.eventually.rejectedWith(Error, 'Invalid options');
-  });
+      it('throws an error for invalid options', async () => {
+        const promise = getSources(['window', 'screen'] as any);
+        await expect(promise).to.be.eventually.rejectedWith(Error, 'Invalid options');
+      });
 
-  // TODO(nornagon): figure out why this test is failing on Linux and re-enable it.
-  ifit(process.platform !== 'linux')('does not throw an error when called more than once (regression)', async () => {
-    const sources1 = await getSources({ types: ['window', 'screen'] });
-    expect(sources1).to.be.an('array').that.is.not.empty();
+      // TODO(nornagon): figure out why this test is failing on Linux and re-enable it.
+      ifit(process.platform !== 'linux')('does not throw an error when called more than once (regression)', async () => {
+        const sources1 = await getSources({ types: ['window', 'screen'] });
+        expect(sources1).to.be.an('array').that.is.not.empty();
 
-    const sources2 = await getSources({ types: ['window', 'screen'] });
-    expect(sources2).to.be.an('array').that.is.not.empty();
-  });
+        const sources2 = await getSources({ types: ['window', 'screen'] });
+        expect(sources2).to.be.an('array').that.is.not.empty();
+      });
 
-  ifit(process.platform !== 'linux')('responds to subsequent calls of different options', async () => {
-    const promise1 = getSources({ types: ['window'] });
-    await expect(promise1).to.eventually.be.fulfilled();
+      ifit(process.platform !== 'linux')('responds to subsequent calls of different options', async () => {
+        const promise1 = getSources({ types: ['window'] });
+        await expect(promise1).to.eventually.be.fulfilled();
 
-    const promise2 = getSources({ types: ['screen'] });
-    await expect(promise2).to.eventually.be.fulfilled();
-  });
+        const promise2 = getSources({ types: ['screen'] });
+        await expect(promise2).to.eventually.be.fulfilled();
+      });
 
-  // Linux doesn't return any window sources.
-  ifit(process.platform !== 'linux')('returns an empty display_id for window sources on Windows and Mac', async () => {
-    const w = new BrowserWindow({ width: 200, height: 200 });
+      // Linux doesn't return any window sources.
+      ifit(process.platform !== 'linux')('returns an empty display_id for window sources on Windows and Mac', async () => {
+        const w = new BrowserWindow({ width: 200, height: 200 });
+        await w.loadURL('about:blank');
 
-    const sources = await getSources({ types: ['window'] });
-    w.destroy();
-    expect(sources).to.be.an('array').that.is.not.empty();
-    for (const { display_id: displayId } of sources) {
-      expect(displayId).to.be.a('string').and.be.empty();
-    }
-  });
+        const sources = await getSources({ types: ['window'] });
+        w.destroy();
+        expect(sources).to.be.an('array').that.is.not.empty();
+        for (const { display_id: displayId } of sources) {
+          expect(displayId).to.be.a('string').and.be.empty();
+        }
+      });
 
-  ifit(process.platform !== 'linux')('returns display_ids matching the Screen API on Windows and Mac', async () => {
-    const displays = screen.getAllDisplays();
-    const sources = await getSources({ types: ['screen'] });
-    expect(sources).to.be.an('array').of.length(displays.length);
+      ifit(process.platform !== 'linux')('returns display_ids matching the Screen API on Windows and Mac', async () => {
+        const displays = screen.getAllDisplays();
+        const sources = await getSources({ types: ['screen'] });
+        expect(sources).to.be.an('array').of.length(displays.length);
 
-    for (let i = 0; i < sources.length; i++) {
-      expect(sources[i].display_id).to.equal(displays[i].id.toString());
-    }
-  });
+        for (let i = 0; i < sources.length; i++) {
+          expect(sources[i].display_id).to.equal(displays[i].id.toString());
+        }
+      });
+    });
+  };
+
+  generateSpecs('in renderer process', getSources);
+  generateSpecs('in main process', desktopCapturer.getSources);
 
   ifit(process.platform !== 'linux')('returns an empty source list if blocked by the main process', async () => {
     w.webContents.once('desktop-capturer-get-sources', (event) => {