From a57c430b09cc57b8197c0e5b64d08a16d0d37b0e Mon Sep 17 00:00:00 2001
From: Hugh Nimmo-Smith <hughns@users.noreply.github.com>
Date: Sun, 11 Sep 2022 22:18:33 +0100
Subject: [PATCH] Implementation of MSC3824 to add action= param on SSO login
 (#2398)
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Co-authored-by: Šimon Brandner <simon.bra.ag@gmail.com>
---
 spec/unit/login.spec.ts | 35 +++++++++++++++++++++++++++++++++++
 src/@types/auth.ts      |  8 ++++++++
 src/client.ts           | 20 +++++++++++++++++---
 3 files changed, 60 insertions(+), 3 deletions(-)

diff --git a/spec/unit/login.spec.ts b/spec/unit/login.spec.ts
index f7cf6d307..6b3ae47fe 100644
--- a/spec/unit/login.spec.ts
+++ b/spec/unit/login.spec.ts
@@ -1,3 +1,4 @@
+import { SSOAction } from '../../src/@types/auth';
 import { TestClient } from '../TestClient';
 
 describe('Login request', function() {
@@ -22,3 +23,37 @@ describe('Login request', function() {
         expect(client.client.getUserId()).toBe(response.user_id);
     });
 });
+
+describe('SSO login URL', function() {
+    let client: TestClient;
+
+    beforeEach(function() {
+        client = new TestClient();
+    });
+
+    afterEach(function() {
+        client.stop();
+    });
+
+    describe('SSOAction', function() {
+        const redirectUri = "https://test.com/foo";
+
+        it('No action', function() {
+            const urlString = client.client.getSsoLoginUrl(redirectUri, undefined, undefined, undefined);
+            const url = new URL(urlString);
+            expect(url.searchParams.has('org.matrix.msc3824.action')).toBe(false);
+        });
+
+        it('register', function() {
+            const urlString = client.client.getSsoLoginUrl(redirectUri, undefined, undefined, SSOAction.REGISTER);
+            const url = new URL(urlString);
+            expect(url.searchParams.get('org.matrix.msc3824.action')).toEqual('register');
+        });
+
+        it('login', function() {
+            const urlString = client.client.getSsoLoginUrl(redirectUri, undefined, undefined, SSOAction.LOGIN);
+            const url = new URL(urlString);
+            expect(url.searchParams.get('org.matrix.msc3824.action')).toEqual('login');
+        });
+    });
+});
diff --git a/src/@types/auth.ts b/src/@types/auth.ts
index db07ce661..86d478944 100644
--- a/src/@types/auth.ts
+++ b/src/@types/auth.ts
@@ -82,3 +82,11 @@ export interface ILoginParams {
     initial_device_display_name?: string;
 }
 /* eslint-enable camelcase */
+
+export enum SSOAction {
+    /** The user intends to login to an existing account */
+    LOGIN = "login",
+
+    /** The user intends to register for a new account */
+    REGISTER = "register",
+}
diff --git a/src/client.ts b/src/client.ts
index 66e3ec2da..27f698b88 100644
--- a/src/client.ts
+++ b/src/client.ts
@@ -188,13 +188,14 @@ import { IPusher, IPusherRequest, IPushRules, PushRuleAction, PushRuleKind, Rule
 import { IThreepid } from "./@types/threepids";
 import { CryptoStore } from "./crypto/store/base";
 import { MediaHandler } from "./webrtc/mediaHandler";
-import { ILoginFlowsResponse, IRefreshTokenResponse } from "./@types/auth";
+import { ILoginFlowsResponse, IRefreshTokenResponse, SSOAction } from "./@types/auth";
 import { TypedEventEmitter } from "./models/typed-event-emitter";
 import { ReceiptType } from "./@types/read_receipts";
 import { MSC3575SlidingSyncRequest, MSC3575SlidingSyncResponse, SlidingSync } from "./sliding-sync";
 import { SlidingSyncSdk } from "./sliding-sync-sdk";
 import { Thread, THREAD_RELATION_TYPE } from "./models/thread";
 import { MBeaconInfoEventContent, M_BEACON_INFO } from "./@types/beacon";
+import { UnstableValue } from "./NamespacedValue";
 import { ToDeviceMessageQueue } from "./ToDeviceMessageQueue";
 import { ToDeviceBatch } from "./models/ToDeviceMessage";
 import { IgnoredInvites } from "./models/invites-ignorer";
@@ -881,6 +882,8 @@ export type ClientEventHandlerMap = {
     & HttpApiEventHandlerMap
     & BeaconEventHandlerMap;
 
+const SSO_ACTION_PARAM = new UnstableValue("action", "org.matrix.msc3824.action");
+
 /**
  * Represents a Matrix Client. Only directly construct this if you want to use
  * custom modules. Normally, {@link createClient} should be used
@@ -7156,15 +7159,26 @@ export class MatrixClient extends TypedEventEmitter<EmittedEvents, ClientEventHa
      * @param {string} loginType The type of SSO login we are doing (sso or cas).
      *     Defaults to 'sso'.
      * @param {string} idpId The ID of the Identity Provider being targeted, optional.
+     * @param {SSOAction} action the SSO flow to indicate to the IdP, optional.
      * @return {string} The HS URL to hit to begin the SSO login process.
      */
-    public getSsoLoginUrl(redirectUrl: string, loginType = "sso", idpId?: string): string {
+    public getSsoLoginUrl(
+        redirectUrl: string,
+        loginType = "sso",
+        idpId?: string,
+        action?: SSOAction,
+    ): string {
         let url = "/login/" + loginType + "/redirect";
         if (idpId) {
             url += "/" + idpId;
         }
 
-        return this.http.getUrl(url, { redirectUrl }, PREFIX_R0);
+        const params = {
+            redirectUrl,
+            [SSO_ACTION_PARAM.unstable!]: action,
+        };
+
+        return this.http.getUrl(url, params, PREFIX_R0);
     }
 
     /**