fix: senderId removed in Electron 28 (#171)

* Accepting ipc events without senderId

Since the property has been removed with Electron 28

* Access senderId on cast event object to be compatible with Electron 28, where "senderId" is removed from IpcRendererEvent

* fix type error

* Implement interface for missing senderId check

* replace process.mainModule with a while loop to get the topmost parent

* disable test using removed APIs

* split the codepaths for electron 28 and electron < 28

* prefix comment for skipped test with TODO

* chore: formatting

---------

Co-authored-by: Jeremy Rose <[email protected]>
Co-authored-by: Kilian Valkhof <[email protected]>
Co-authored-by: David Sanders <[email protected]>

.circleci/config.yml

@@ -48,6 +48,7 @@ workflows:
                 - 25
                 - 26
                 - 27
+                - 28
       - cfa/release:
           requires:
             - test-electron

src/main/server.ts

@@ -385,7 +385,17 @@ export function initialize() {
       if (customEvent.defaultPrevented) {
         throw new Error(`Blocked remote.require('${moduleName}')`)
       } else {
-        customEvent.returnValue = process.mainModule!.require(moduleName)
+        // electron < 28
+        if (process.mainModule) {
+          customEvent.returnValue = process.mainModule!.require(moduleName)
+        } else {
+          // electron >= 28
+          let mainModule = module;
+          while (mainModule.parent) {
+            mainModule = mainModule.parent;
+          }
+          customEvent.returnValue = mainModule.require(moduleName)
+        }
       }
     }
 

src/renderer/remote.ts

@@ -1,7 +1,7 @@
 import { CallbacksRegistry } from './callbacks-registry'
 import { isPromise, isSerializableObject, serialize, deserialize } from '../common/type-utils'
 import { MetaTypeFromRenderer, ObjectMember, ObjProtoDescriptor, MetaType } from '../common/types'
-import { BrowserWindow, WebContents, ipcRenderer } from 'electron'
+import { BrowserWindow, WebContents, ipcRenderer, IpcRendererEvent } from 'electron'
 import { browserModuleNames } from '../common/module-names'
 import { getElectronBinding } from '../common/get-electron-binding'
 import { IPC_MESSAGES } from '../common/ipc-messages';
@@ -309,11 +309,22 @@ function metaToError (meta: { type: 'error', value: any, members: ObjectMember[]
   return obj
 }
 
+// Backwards compatibility interface for Electron < v28
+interface IpcRendererEventWithSenderId extends IpcRendererEvent {
+	senderId: number
+}
+
+function hasSenderId(input: any): input is IpcRendererEventWithSenderId {
+	return typeof input.senderId === "number"
+}
+
 function handleMessage (channel: string, handler: Function) {
   ipcRenderer.on(channel, (event, passedContextId, id, ...args) => {
-    if (event.senderId !== 0) {
-      console.error(`Message ${channel} sent by unexpected WebContents (${event.senderId})`);
-      return;
+    if (hasSenderId(event)) {
+      if (event.senderId !== 0 && event.senderId !== undefined) {
+        console.error(`Message ${channel} sent by unexpected WebContents (${event.senderId})`);
+        return;
+      }
     }
 
     if (passedContextId === contextId) {

test/all.ts

@@ -498,7 +498,12 @@ describe('remote module', () => {
       expect(a.getConstructorName(new (class {})())).to.equal('')
     })
 
-    it('should search module from the user app', async () => {
+    /* TODO: Electron 28 removed process.mainModule, so we need to find an alternative way to test that the remotely 
+       required module in the renderer uses the same main module as the main process. In src/main/server.ts:388 we do so 
+       by looping over the module parents until getting the top most one and using their require, but that require 
+       doesn't send along the module paths, so we can't use it here. */
+
+    it.skip('should search module from the user app', async () => {
       expectPathsEqual(
         path.normalize(await remotely(() => require('./renderer').process.mainModule!.filename)),
         path.resolve(__dirname, 'index.js')
@@ -887,7 +892,7 @@ describe('remote module', () => {
         } catch (e) {
           done(e)
         } finally {
-          process.off('unhandledRejection', onUnhandledRejection)
+          process.off('unhandledRejection' as any, onUnhandledRejection)
         }
       })
     })