Use membershipID for session events (#5105)

* User membershipID for session events

* fix tests

Author: toger5

spec/unit/matrixrtc/CallMembership.spec.ts

@@ -170,7 +170,7 @@ describe("CallMembership", () => {
                 expect(membership.scope).toBe("m.room");
             });
             it("returns correct membershipID", () => {
-                expect(membership.membershipID).toBe("0");
+                expect(membership.membershipID).toBe("@alice:example.org:AAAAAAA");
             });
             it("returns correct unused fields", () => {
                 expect(membership.getAbsoluteExpiry()).toBe(DEFAULT_EXPIRE_DURATION);

spec/unit/matrixrtc/MembershipManager.spec.ts

@@ -143,6 +143,7 @@ describe("MembershipManager", () => {
                         device_id: "AAAAAAA",
                         expires: 14400000,
                         foci_preferred: [focus],
+                        membershipID: "@alice:example.org:AAAAAAA",
                         focus_active: focusActive,
                         scope: "m.room",
                     },
@@ -263,6 +264,7 @@ describe("MembershipManager", () => {
                             expires: 14400000,
                             device_id: "AAAAAAA",
                             foci_preferred: [focus],
+                            membershipID: "@alice:example.org:AAAAAAA",
                             focus_active: focusActive,
                         } satisfies SessionMembershipData,
                         userStateKey,
@@ -383,6 +385,7 @@ describe("MembershipManager", () => {
                     device_id: "AAAAAAA",
                     expires: 1234567,
                     foci_preferred: [focus],
+                    membershipID: "@alice:example.org:AAAAAAA",
                     focus_active: {
                         focus_selection: "oldest_membership",
                         type: "livekit",

src/matrixrtc/CallMembership.ts

@@ -31,7 +31,16 @@ import { logger } from "../logger.ts";
 export const DEFAULT_EXPIRE_DURATION = 1000 * 60 * 60 * 4;
 
 type CallScope = "m.room" | "m.user";
-type Member = { user_id: string; device_id: string; id: string };
+type Member = {
+    user_id: string;
+    device_id: string;
+    /**
+     * The id used on the media backend.
+     * (With livekit this is the participant identity on the LK SFU)
+     * This can be a UUID but right now it is `${this.matrixEventData.sender}:${data.device_id}`.
+     */
+    id: string;
+};
 
 export interface RtcMembershipData {
     "slot_id": string;
@@ -199,6 +208,15 @@ export type SessionMembershipData = {
      * The sticky key in case of a sticky event. This string encodes the application + device_id indicating the used slot + device.
      */
     "msc4354_sticky_key"?: string;
+
+    /**
+     * The id used on the media backend.
+     * (With livekit this is the participant identity on the LK SFU)
+     * This can be a UUID but right now it is `${this.matrixEventData.sender}:${data.device_id}`.
+     *
+     * It is compleatly valid to not set this field. Other clients will treat `undefined` as `${this.matrixEventData.sender}:${data.device_id}`
+     */
+    "membershipID"?: string;
 };
 
 const checkSessionsMembershipData = (data: IContent, errors: string[]): data is SessionMembershipData => {
@@ -378,7 +396,18 @@ export class CallMembership {
                 return data.scope;
         }
     }
-
+    /**
+     * This computes the membership ID for the membership.
+     * for the sticky event based rtcSessionData this is trivial it is `member.id`.
+     *
+     * For the legacy sessionMemberEvents it is a bit more complex. Here we sometimes do not have this data
+     * in the event content and we expected the SFU and the client to use `${this.matrixEventData.sender}:${data.device_id}`.
+     *
+     * So if there is no membershipID we use the hard coded jwt id default (`${this.matrixEventData.sender}:${data.device_id}`)
+     * value (used until version 0.16.0)
+     *
+     * It is also possible for a session event to set a custom membershipID. in that case this will be used.
+     */
     public get membershipID(): string {
         // the createdTs behaves equivalent to the membershipID.
         // we only need the field for the legacy member events where we needed to update them
@@ -389,7 +418,12 @@ export class CallMembership {
                 return data.member.id;
             case "session":
             default:
-                return (this.createdTs() ?? "").toString();
+                return (
+                    // best case we have a client already publishing the right custom membershipId
+                    data.membershipID ??
+                    // alternativly we use the hard coded jwt id defuatl value (used until version 0.16.0)
+                    `${this.matrixEventData.sender}:${data.device_id}`
+                );
         }
     }
 

src/matrixrtc/MembershipManager.ts

@@ -276,13 +276,8 @@ export class MembershipManager
         if (!this.isActivated()) {
             return Promise.resolve();
         }
-        const userId = this.client.getUserId();
-        const deviceId = this.client.getDeviceId();
-        if (!userId || !deviceId) {
-            this.logger.error("MembershipManager.onRTCSessionMemberUpdate called without user or device id");
-            return Promise.resolve();
-        }
-        this._ownMembership = memberships.find((m) => isMyMembership(m, userId, deviceId));
+
+        this._ownMembership = memberships.find((m) => isMyMembership(m, this.userId, this.deviceId));
 
         if (!this._ownMembership) {
             // If one of these actions are scheduled or are getting inserted in the next iteration, we should already
@@ -338,6 +333,7 @@ export class MembershipManager
         if (userId === null) throw Error("Missing userId in client");
         if (deviceId === null) throw Error("Missing deviceId in client");
         this.deviceId = deviceId;
+        this.userId = userId;
         // this needs to become a uuid so that consecutive join/leaves result in a key rotation.
         // we keep it as a string for now for backwards compatibility.
         this.memberId = this.makeMembershipStateKey(userId, deviceId);
@@ -386,6 +382,7 @@ export class MembershipManager
     }
     // Membership Event static parameters:
     protected deviceId: string;
+    protected userId: string;
     protected memberId: string;
     protected rtcTransport?: Transport;
     /** @deprecated This will be removed in favor or rtcTransport becoming a list of actively used transports */
@@ -763,6 +760,10 @@ export class MembershipManager
     }
 
     // HELPERS
+    /**
+     * this creates `${localUserId}_${localDeviceId}_${this.slotDescription.application}${this.slotDescription.id}`
+     * which is not compatible with membershipID of session type member events. They have to be `${localUserId}:${localDeviceId}`
+     */
     private makeMembershipStateKey(localUserId: string, localDeviceId: string): string {
         const stateKey = `${localUserId}_${localDeviceId}_${this.slotDescription.application}${this.slotDescription.id}`;
         if (/^org\.matrix\.msc(3757|3779)\b/.exec(this.room.getVersion())) {
@@ -793,6 +794,10 @@ export class MembershipManager
             "call_id": this.slotDescription.id,
             "scope": "m.room",
             "device_id": this.deviceId,
+            // DO NOT use this.memberId here since that is the state key (using application...)
+            // But for session events we use the colon seperated userId and deviceId. The SFU will automatically
+            // assign those values to the media participant for those versions.
+            "membershipID": `${this.userId}:${this.deviceId}`,
             expires,
             "m.call.intent": this.callIntent,
             ...focusObjects,
@@ -1083,7 +1088,7 @@ export class StickyEventMembershipManager extends MembershipManager {
             },
             slot_id: slotDescriptionToId(this.slotDescription),
             rtc_transports: this.rtcTransport ? [this.rtcTransport] : [],
-            member: { device_id: this.deviceId, user_id: this.client.getUserId()!, id: this.memberId },
+            member: { device_id: this.deviceId, user_id: this.userId, id: this.memberId },
             versions: [],
             ...relationObject,
         };