Support build-time specified protocol scheme for oidc callback

src/@types/global.d.ts

@@ -130,6 +130,11 @@ declare global {
     interface Electron {
         on(channel: ElectronChannel, listener: (event: Event, ...args: any[]) => void): void;
         send(channel: ElectronChannel, ...args: any[]): void;
+        initialise(): Promise<{
+            protocol: string;
+            sessionId: string;
+            config: IConfigOptions;
+        }>;
     }
 
     interface DesktopCapturerSource {

src/vector/platform/ElectronPlatform.tsx

@@ -17,7 +17,6 @@ import {
     type OidcRegistrationClientMetadata,
 } from "matrix-js-sdk/src/matrix";
 import React from "react";
-import { secureRandomString } from "matrix-js-sdk/src/randomstring";
 import { logger } from "matrix-js-sdk/src/logger";
 
 import BasePlatform, { UpdateCheckStatus, type UpdateStatus } from "../../BasePlatform";
@@ -97,8 +96,10 @@ function getUpdateCheckStatus(status: boolean | string): UpdateStatus {
 export default class ElectronPlatform extends BasePlatform {
     private readonly ipc = new IPCManager("ipcCall", "ipcReply");
     private readonly eventIndexManager: BaseEventIndexManager = new SeshatIndexManager();
-    // this is the opaque token we pass to the HS which when we get it in our callback we can resolve to a profile
-    private readonly ssoID: string = secureRandomString(32);
+    private readonly initialised: Promise<void>;
+    private protocol!: string;
+    private sessionId!: string;
+    private config!: IConfigOptions;
 
     public constructor() {
         super();
@@ -186,13 +187,21 @@ export default class ElectronPlatform extends BasePlatform {
             await this.ipc.call("callDisplayMediaCallback", source ?? { id: "", name: "", thumbnailURL: "" });
         });
 
-        void this.ipc.call("startSSOFlow", this.ssoID);
-
         BreadcrumbsStore.instance.on(UPDATE_EVENT, this.onBreadcrumbsUpdate);
+
+        this.initialised = this.initialise();
+    }
+
+    private async initialise(): Promise<void> {
+        const { protocol, sessionId, config } = await window.electron!.initialise();
+        this.protocol = protocol;
+        this.sessionId = sessionId;
+        this.config = config;
     }
 
     public async getConfig(): Promise<IConfigOptions | undefined> {
-        return this.ipc.call("getConfig");
+        await this.initialised;
+        return this.config;
     }
 
     private onBreadcrumbsUpdate = (): void => {
@@ -391,7 +400,7 @@ export default class ElectronPlatform extends BasePlatform {
     public getSSOCallbackUrl(fragmentAfterLogin?: string): URL {
         const url = super.getSSOCallbackUrl(fragmentAfterLogin);
         url.protocol = "element";
-        url.searchParams.set(SSO_ID_KEY, this.ssoID);
+        url.searchParams.set(SSO_ID_KEY, this.sessionId);
         return url;
     }
 
@@ -469,15 +478,15 @@ export default class ElectronPlatform extends BasePlatform {
     }
 
     public getOidcClientState(): string {
-        return `:${SSO_ID_KEY}:${this.ssoID}`;
+        return `:${SSO_ID_KEY}:${this.sessionId}`;
     }
 
     /**
      * The URL to return to after a successful OIDC authentication
      */
     public getOidcCallbackUrl(): URL {
         const url = super.getOidcCallbackUrl();
-        url.protocol = "io.element.desktop";
+        url.protocol = this.protocol;
         // Trim the double slash into a single slash to comply with https://datatracker.ietf.org/doc/html/rfc8252#section-7.1
         if (url.href.startsWith(`${url.protocol}//`)) {
             url.href = url.href.replace("://", ":/");

test/unit-tests/vector/platform/ElectronPlatform-test.ts

@@ -31,6 +31,11 @@ describe("ElectronPlatform", () => {
     const mockElectron = {
         on: jest.fn(),
         send: jest.fn(),
+        initialise: jest.fn().mockResolvedValue({
+            protocol: "io.element.desktop",
+            sessionId: "session-id",
+            config: { _config: true },
+        }),
     };
 
     const dispatchSpy = jest.spyOn(dispatcher, "dispatch");
@@ -64,6 +69,17 @@ describe("ElectronPlatform", () => {
         expect(rageshake.flush).toHaveBeenCalled();
     });
 
+    it("should load config", async () => {
+        const platform = new ElectronPlatform();
+        await expect(platform.getConfig()).resolves.toEqual({ _config: true });
+    });
+
+    it("should return oidc client state as expected", async () => {
+        const platform = new ElectronPlatform();
+        await platform.getConfig();
+        expect(platform.getOidcClientState()).toMatchInlineSnapshot(`":element-desktop-ssoid:session-id"`);
+    });
+
     it("dispatches view settings action on preferences event", () => {
         new ElectronPlatform();
         const [event, handler] = getElectronEventHandlerCall("preferences")!;
@@ -287,7 +303,7 @@ describe("ElectronPlatform", () => {
         });
     });
 
-    describe("breacrumbs", () => {
+    describe("breadcrumbs", () => {
         it("should send breadcrumb updates over the IPC", () => {
             const spy = jest.spyOn(BreadcrumbsStore.instance, "on");
             new ElectronPlatform();