feat(queue-service): add removeListener method

Closes #70

README.md

@@ -386,6 +386,20 @@ the connections defined in the `forRoot` method contains a connection named `Con
 > Note: If you leave out the name of the connection, the listener will be attached to the default connection (if exists).
 
 
+### Removing a listener
+
+If you want to remove a listener, you can use the `removeListener()` method of the `QueueService`. The method's first parameter is the name string or `Source` object of the queue, and the second (optional) parameter is the connection name if you have set it up. Here is an example:
+
+```typescript
+// with the default connection
+await this.queueService.removeListener('example');
+```
+
+```typescript
+// with named connection
+await this.queueService.removeListener('example', Connections.TEST);
+```
+
 ### Message control
 
 When a new message arrives at a queue, the assigned method with `@Listen()` decorator receives the transformed and validated message body

src/service/queue/queue.service.spec.ts

@@ -61,7 +61,7 @@ describe('QueueService', () => {
         {
           provide: AMQPService,
           useValue: {
-            createReceiver: jest.fn().mockResolvedValue(jest.fn()),
+            createReceiver: jest.fn().mockResolvedValue(jest.fn().mockResolvedValue(new EventContextMock().receiver)),
             createSender: jest.fn().mockResolvedValue(new EventContextMock().sender),
             disconnect: jest.fn().mockResolvedValue(jest.fn()),
             getModuleOptions(): QueueModuleOptions {
@@ -349,6 +349,62 @@ describe('QueueService', () => {
     });
   });
 
+  describe('removeListener()', () => {
+    it('should remove listener', async () => {
+      (amqpService.createReceiver as jest.Mock).mockResolvedValue(new EventContextMock().receiver);
+      await queueService.listen(defaultQueue, () => void 0, {});
+      expect(queueService['receivers'].size).toBe(1);
+
+      const receiver = queueService['receivers'].get(queueService['receivers'].keys().next().value);
+
+      const result = await queueService.removeListener(defaultQueue);
+      expect(receiver.close).toBeCalled();
+      expect(result).toBe(true);
+      expect(queueService['receivers'].size).toBe(0);
+    });
+
+    it('should remove listener with connectionName', async () => {
+      (amqpService.createReceiver as jest.Mock).mockResolvedValue(new EventContextMock().receiver);
+      const connection = 'test_connection';
+      await queueService.listen(defaultQueue, () => void 0, {}, connection);
+
+      const receiver = queueService['receivers'].get(queueService['receivers'].keys().next().value);
+
+      expect(queueService['receivers'].size).toBe(1);
+
+      const result = await queueService.removeListener(defaultQueue, connection);
+      expect(receiver.close).toBeCalled();
+      expect(result).toBe(true);
+      expect(queueService['receivers'].size).toBe(0);
+    });
+
+    it('should remove listener with Source object', async () => {
+      (amqpService.createReceiver as jest.Mock).mockResolvedValue(new EventContextMock().receiver);
+      const source: Source = {
+        address: defaultQueue,
+        filter: filter.selector("((JMSCorrelationID) <> ''"),
+      };
+      await queueService.listen(source, () => void 0, {});
+      expect(queueService['receivers'].size).toBe(1);
+      const receiver = queueService['receivers'].get(queueService['receivers'].keys().next().value);
+
+      const result = await queueService.removeListener(source);
+      expect(receiver.close).toBeCalled();
+      expect(result).toBe(true);
+      expect(queueService['receivers'].size).toBe(0);
+    });
+
+    it('should not do anything with non-existing listener', async () => {
+      (amqpService.createReceiver as jest.Mock).mockResolvedValue(new EventContextMock().receiver);
+      await queueService.listen(defaultQueue, () => void 0, {});
+      expect(queueService['receivers'].size).toBe(1);
+
+      const result = await queueService.removeListener('otherQueue');
+      expect(result).toBe(false);
+      expect(queueService['receivers'].size).toBe(1);
+    });
+  });
+
   it('should shutdown', async () => {
     (amqpService.createReceiver as jest.Mock).mockResolvedValue(new EventContextMock().receiver);
     await queueService.listen(defaultQueue, () => void 0, {});

src/service/queue/queue.service.ts

@@ -42,7 +42,7 @@ export class QueueService {
    * objects when a new message arrives on the queue. If a receiver is already
    * created for the given queue then a new receiver won't be created.
    *
-   * @param {string} source Name of the queue.
+   * @param {string} source Name or Source object of the queue.
    * @param {function(body: T, control: MessageControl, metadata: Omit<Message, 'body'>) => Promise<void>} callback Function what will invoked when message arrives.
    * @param {ListenOptions<T>} options Options for message processing.
    * @param {string} connection Name of the connection
@@ -300,27 +300,46 @@ export class QueueService {
     this.receivers.clear();
   }
 
+  /**
+   * Removes listener from active listeners
+   *
+   * @param {string} source Name or Source object of the queue.
+   * @param {string} connection Name of the connection
+   *
+   * @returns {Promise<boolean>} Returns true if listener was removed, otherwise false. If listener was not found, returns false.
+   *
+   * @public
+   */
+  public async removeListener(source: string | Source, connection: string = AMQP_DEFAULT_CONNECTION_TOKEN): Promise<boolean> {
+    const sourceToken = typeof source === 'string' ? source : JSON.stringify(source);
+    const receiverToken = this.getLinkToken(sourceToken, connection);
+
+    if (this.receivers.has(receiverToken)) {
+      const receiver = this.receivers.get(receiverToken);
+      await receiver.close();
+
+      return this.receivers.delete(receiverToken);
+    }
+
+    return false;
+  }
+
   private async getReceiver(
     source: string | Source,
     credit: number,
     messageHandler: (context: EventContext) => Promise<void>,
     connection: string,
   ): Promise<Receiver> {
-    let receiver;
-
     const sourceToken = typeof source === 'string' ? source : JSON.stringify(source);
 
     const receiverToken = this.getLinkToken(sourceToken, connection);
 
-    if (this.receivers.has(receiverToken)) {
-      receiver = this.receivers.get(receiverToken);
-    } else {
-      receiver = await this.amqpService.createReceiver(source, credit, messageHandler.bind(this), connection);
-
+    if (!this.receivers.has(receiverToken)) {
+      const receiver = await this.amqpService.createReceiver(source, credit, messageHandler.bind(this), connection);
       this.receivers.set(receiverToken, receiver);
     }
 
-    return receiver;
+    return this.receivers.get(receiverToken);
   }
 
   private async getSender(target: string, connection: string): Promise<AwaitableSender> {

src/test/event-context.mock.ts

@@ -29,7 +29,7 @@ export class EventContextMock implements EventContext {
     },
     credit: 0,
     addCredit: jest.fn(),
-    close: jest.fn().mockResolvedValue(true),
+    close: jest.fn(() => true),
   };
   public sender: any = {
     send: jest.fn().mockResolvedValue({ sent: true }),