Enhancement: websocket heartbeat (#13739)

---------

Co-authored-by: shamoon <4887959+shamoon@users.noreply.github.com>

src-ui/src/app/services/websocket-status.service.spec.ts

@@ -438,6 +438,21 @@ describe('ConsumerStatusService', () => {
     expect(updated).toBeTruthy()
   })
 
+  it('should ignore keep-alive heartbeat messages from the server', () => {
+    let updated = false
+    let deleted = false
+    websocketStatusService.onDocumentUpdated().subscribe(() => (updated = true))
+    websocketStatusService.onDocumentDeleted().subscribe(() => (deleted = true))
+
+    websocketStatusService.connect()
+    server.send({ type: WebsocketStatusType.HEARTBEAT })
+
+    expect(updated).toBeFalsy()
+    expect(deleted).toBeFalsy()
+    expect(websocketStatusService.getConsumerStatus()).toHaveLength(0)
+    websocketStatusService.disconnect()
+  })
+
   it('should ignore document updated events the user cannot view', () => {
     let updated = false
     websocketStatusService.onDocumentUpdated().subscribe(() => {

src-ui/src/app/services/websocket-status.service.ts

@@ -11,6 +11,7 @@ export enum WebsocketStatusType {
   STATUS_UPDATE = 'status_update',
   DOCUMENTS_DELETED = 'documents_deleted',
   DOCUMENT_UPDATED = 'document_updated',
+  HEARTBEAT = 'heartbeat',
 }
 
 // see ProgressStatusOptions in src/documents/plugins/helpers.py
@@ -207,6 +208,10 @@ export class WebsocketStatusService {
         case WebsocketStatusType.STATUS_UPDATE:
           this.handleProgressUpdate(messageData as WebsocketProgressMessage)
           break
+
+        case WebsocketStatusType.HEARTBEAT:
+          // keep-alive from the server, see paperless.consumers.StatusConsumer
+          break
       }
     }
   }