Decouple SubscriptionController from Controller

Remove the reliance a reference to the Controller to get the link that a
subscription is tied to by explicitly handling the SubscriptionRequest
and passing the link to the SubscriptionController.

packages/controller/src/BaseConnection.ts

@@ -34,6 +34,7 @@ export default class BaseConnection extends lib.Link {
 		this.handle(lib.ModPackGetDefaultRequest, this.handleModPackGetDefaultRequest.bind(this));
 		this.handle(lib.ModDownloadRequest, this.handleModDownloadRequest.bind(this));
 
+		this.handle(lib.SubscriptionRequest, this.handleSubscriptionRequest.bind(this));
 		this.connector.on("close", () => {
 			this._controller.subscriptions.unsubscribe(this);
 		});
@@ -102,4 +103,8 @@ export default class BaseConnection extends lib.Link {
 
 		return stream.id;
 	}
+
+	async handleSubscriptionRequest(request: lib.SubscriptionRequest, src: lib.Address, dst: lib.Address) {
+		return await this._controller.subscriptions.handleRequest(this, request, src, dst);
+	}
 }

packages/controller/src/Controller.ts

@@ -76,7 +76,7 @@ export default class Controller {
 	private _events: events.EventEmitter = new events.EventEmitter();
 
 	/** Event subscription controller */
-	subscriptions: lib.SubscriptionController;
+	subscriptions = new lib.SubscriptionController();
 
 	// Possible states are new, starting, running, stopping, stopped
 	private _state: string = "new";
@@ -148,7 +148,6 @@ export default class Controller {
 		this.app.locals.streams = new Map();
 
 		this.wsServer = new WsServer(this);
-		this.subscriptions = new lib.SubscriptionController(this);
 
 		this.modStore.on("change", mod => {
 			this.modsUpdated([mod]);

packages/lib/src/subscriptions.ts

@@ -111,12 +111,6 @@ type EventData = {
 export class SubscriptionController {
 	_events = new Map<string, EventData>();
 
-	constructor(
-		private controller: any, // Controller | Link
-	) {
-		this.controller.handle(SubscriptionRequest, this._handleRequest.bind(this));
-	}
-
 	/**
 	 * Allow clients to subscribe to an event by telling the subscription controller to accept them
 	 * Has an optional subscription update handler which is called when a client subscribes
@@ -172,14 +166,14 @@ export class SubscriptionController {
 	}
 
 	/**
-	 * Handle incoming event subscription requests
+	 * Handle incoming subscription requests on a link
+	 * @param link - Link message was received on
 	 * @param event - incomming event.
 	 * @param src - Source address of incomming request.
 	 * @param dst - destination address of incomming request.
 	 * @returns Response to subscription request.
-	 * @internal
 	 */
-	async _handleRequest(event: SubscriptionRequest, src: Address, dst: Address) {
+	async handleRequest(link: Link, event: SubscriptionRequest, src: Address, dst: Address) {
 		if (!Link._eventsByName.has(event.eventName)) {
 			throw new Error(`Event ${event.eventName} is not a registered event`);
 		}
@@ -188,7 +182,6 @@ export class SubscriptionController {
 			throw new Error(`Event ${event.eventName} is not a registered as subscribable`);
 		}
 		let eventReplay: Event<unknown> | null = null;
-		const link: Link = this.controller.wsServer.controlConnections.get(src.id);
 		if (event.subscribe === false) {
 			eventData.subscriptions.delete(link);
 		} else {

test/lib/subscriptions.js

@@ -147,20 +147,22 @@ describe("lib/subscriptions", function() {
 			dst: addr("controller"),
 		}];
 
+		function getLink(id) {
+			return mockController.wsServer.controlConnections.get(id);
+		}
 		function onceConnectorSend(id) {
-			const link = mockController.wsServer.controlConnections.get(id);
-			return events.once(link.connector, "send");
+			return events.once(getLink(id).connector, "send");
 		}
 
 		function assertLastEvent(connectorId, Event) {
-			const link = mockController.wsServer.controlConnections.get(connectorId);
+			const link = getLink(connectorId);
 			const lastMessage = link.connector.sentMessages.at(-1);
 			const name = Event.plugin ? `${Event.plugin}:${Event.name}` : Event.name;
 			assert.equal(lastMessage.name, name);
 		}
 
 		function assertNoEvent(connectorId) {
-			const link = mockController.wsServer.controlConnections.get(connectorId);
+			const link = getLink(connectorId);
 			assert.equal(link.connector.sentMessages.length, 0);
 		}
 
@@ -174,10 +176,6 @@ describe("lib/subscriptions", function() {
 			subscriptions = new lib.SubscriptionController(mockController);
 		});
 
-		it("should handle the SubscriptionRequest event", function() {
-			assert.equal(mockController.handles.has(lib.SubscriptionRequest), true);
-		});
-
 		describe("handle()", function() {
 			it("should accept registered events", function() {
 				subscriptions.handle(RegisteredEvent);
@@ -201,7 +199,9 @@ describe("lib/subscriptions", function() {
 			beforeEach(function() {
 				subscriptions.handle(RegisteredEvent);
 				for (let connectorData of connectorSetupDate) {
-					subscriptions._handleRequest(connectorData.request, connectorData.src, connectorData.dst);
+					subscriptions.handleRequest(
+						getLink(connectorData.id), connectorData.request, connectorData.src, connectorData.dst
+					);
 				}
 			});
 
@@ -226,15 +226,17 @@ describe("lib/subscriptions", function() {
 			it("should not notify a link who unsubscribed", async function() {
 				const connectorData = connectorSetupDate[0];
 				const request = new lib.SubscriptionRequest(RegisteredEvent.name, false);
-				await subscriptions._handleRequest(request, connectorData.src, connectorData.dst);
-				mockController.wsServer.controlConnections.get(0).connector.sentMessages.pop(); // Response to request
+				await subscriptions.handleRequest(
+					getLink(connectorData.id), request, connectorData.src, connectorData.dst,
+				);
+				getLink(0).connector.sentMessages.pop(); // Response to request
 				subscriptions.broadcast(new RegisteredEvent());
 				await onceConnectorSend(1);
 				assertNoEvent(0);
 				assertLastEvent(1, RegisteredEvent);
 			});
 			it("should not notify links which are closed or closing", async function() {
-				const link = mockController.wsServer.controlConnections.get(0);
+				const link = getLink(0);
 				link.connector.closing = true;
 				subscriptions.broadcast(new RegisteredEvent());
 				await onceConnectorSend(1);
@@ -247,12 +249,14 @@ describe("lib/subscriptions", function() {
 			beforeEach(function() {
 				subscriptions.handle(RegisteredEvent);
 				for (let connectorData of connectorSetupDate) {
-					subscriptions._handleRequest(connectorData.request, connectorData.src, connectorData.dst);
+					subscriptions.handleRequest(
+						getLink(connectorData.id), connectorData.request, connectorData.src, connectorData.dst
+					);
 				}
 			});
 
 			it("should remove an active subscription", async function() {
-				const link = mockController.wsServer.controlConnections.get(0);
+				const link = getLink(0);
 				subscriptions.unsubscribe(link);
 				subscriptions.broadcast(new RegisteredEvent());
 				await onceConnectorSend(1);
@@ -261,7 +265,7 @@ describe("lib/subscriptions", function() {
 			});
 		});
 
-		describe("_handleRequest()", function() {
+		describe("handleRequest()", function() {
 			beforeEach(function() {
 				subscriptions.handle(RegisteredEvent);
 			});
@@ -270,7 +274,7 @@ describe("lib/subscriptions", function() {
 				const request = new lib.SubscriptionRequest(RegisteredEvent.name, true);
 				request.eventName = UnregisteredEvent.name;
 				assert.rejects(
-					subscriptions._handleRequest(request, addr({ controlId: 0 }), addr("controller")),
+					subscriptions.handleRequest(getLink(0), request, addr({ controlId: 0 }), addr("controller")),
 					new Error(`Unregistered Event class ${UnregisteredEvent.name}`)
 				);
 			});
@@ -278,29 +282,35 @@ describe("lib/subscriptions", function() {
 				const request = new lib.SubscriptionRequest(RegisteredEvent.name, true);
 				request.eventName = StringPermissionEvent.name;
 				assert.rejects(
-					subscriptions._handleRequest(request, addr({ controlId: 0 }), addr("controller")),
+					subscriptions.handleRequest(getLink(0), request, addr({ controlId: 0 }), addr("controller")),
 					new Error(`Event ${StringPermissionEvent.eventName} is not a registered as subscribable`)
 				);
 			});
 			it("should accept a subscription", async function() {
 				const request = new lib.SubscriptionRequest(RegisteredEvent.name, true);
-				await subscriptions._handleRequest(request, connectorSetupDate[0].src, connectorSetupDate[0].dst);
+				await subscriptions.handleRequest(
+					getLink(0), request, connectorSetupDate[0].src, connectorSetupDate[0].dst
+				);
 				subscriptions.broadcast(new RegisteredEvent());
 				await onceConnectorSend(0);
 				assertLastEvent(0, RegisteredEvent);
 			});
 			it("should accept a unsubscription", async function() {
 				const request = new lib.SubscriptionRequest(RegisteredEvent.name, true);
-				await subscriptions._handleRequest(request, connectorSetupDate[0].src, connectorSetupDate[0].dst);
+				await subscriptions.handleRequest(
+					getLink(0), request, connectorSetupDate[0].src, connectorSetupDate[0].dst
+				);
 				subscriptions.broadcast(new RegisteredEvent());
 				await onceConnectorSend(0);
 				assertLastEvent(0, RegisteredEvent);
 
-				const link = mockController.wsServer.controlConnections.get(0);
+				const link = getLink(0);
 				link.connector.sentMessages.pop();
 
 				const unsubRequest = new lib.SubscriptionRequest(RegisteredEvent.name, false);
-				await subscriptions._handleRequest(unsubRequest, connectorSetupDate[0].src, connectorSetupDate[0].dst);
+				await subscriptions.handleRequest(
+					getLink(0), unsubRequest, connectorSetupDate[0].src, connectorSetupDate[0].dst
+				);
 				subscriptions.broadcast(new RegisteredEvent());
 				assertNoEvent(0);
 			});
@@ -310,12 +320,14 @@ describe("lib/subscriptions", function() {
 				});
 
 				const request = new lib.SubscriptionRequest(StringPermissionEvent.name, true);
-				await subscriptions._handleRequest(request, connectorSetupDate[0].src, connectorSetupDate[0].dst);
+				await subscriptions.handleRequest(
+					getLink(0), request, connectorSetupDate[0].src, connectorSetupDate[0].dst
+				);
 				subscriptions.broadcast(new StringPermissionEvent());
 				await onceConnectorSend(0);
 				assertLastEvent(0, StringPermissionEvent);
 
-				const link = mockController.wsServer.controlConnections.get(0);
+				const link = getLink(0);
 				const lastMessage = link.connector.sentMessages.pop();
 				const eventEntry = lib.Link._eventsByClass.get(StringPermissionEvent);
 				const response = eventEntry.eventFromJSON(lastMessage.data);