fix(sync): skip sync requests while offline

Author: sleidig

src/app/core/database/sync.service.spec.ts

@@ -7,20 +7,25 @@ import { LoginStateSubject, SyncStateSubject } from "../session/session-type";
 import { LoginState } from "../session/session-states/login-state.enum";
 import { KeycloakAuthService } from "../session/auth/keycloak/keycloak-auth.service";
 import { Subject } from "rxjs";
+import { NAVIGATOR_TOKEN } from "../../utils/di-tokens";
 
 describe("SyncService", () => {
   let service: SyncService;
   let loginState: LoginStateSubject;
   let mockAuthService: jasmine.SpyObj<KeycloakAuthService>;
+  let mockNavigator;
 
   beforeEach(() => {
     mockAuthService = jasmine.createSpyObj(["login", "addAuthHeader"]);
+    mockNavigator = { onLine: true };
+
     TestBed.configureTestingModule({
       providers: [
         { provide: KeycloakAuthService, useValue: mockAuthService },
         { provide: Database, useClass: PouchDatabase },
         LoginStateSubject,
         SyncStateSubject,
+        { provide: NAVIGATOR_TOKEN, useValue: mockNavigator },
       ],
     });
     service = TestBed.inject(SyncService);
@@ -94,4 +99,24 @@ describe("SyncService", () => {
 
     stopPeriodicTimer();
   }));
+
+  it("should skip sync calls when offline", fakeAsync(() => {
+    const mockLocalDb = jasmine.createSpyObj(["sync"]);
+    mockLocalDb.sync.and.resolveTo({});
+    const db = TestBed.inject(Database) as PouchDatabase;
+    spyOn(db, "getPouchDB").and.returnValue(mockLocalDb);
+
+    mockNavigator.onLine = false;
+
+    service.startSync();
+
+    tick(1000);
+    expect(mockLocalDb.sync).not.toHaveBeenCalled();
+
+    mockNavigator.onLine = true;
+    tick(SyncService.SYNC_INTERVAL);
+    expect(mockLocalDb.sync).toHaveBeenCalled();
+
+    stopPeriodicTimer();
+  }));
 });

src/app/core/database/sync.service.ts

@@ -1,4 +1,4 @@
-import { Injectable } from "@angular/core";
+import { Inject, Injectable } from "@angular/core";
 import { Database } from "./database";
 import { PouchDatabase } from "./pouch-database";
 import { Logging } from "../logging/logging.service";
@@ -16,6 +16,7 @@ import { Config } from "../config/config";
 import { Entity } from "../entity/model/entity";
 import { from, interval, merge, of } from "rxjs";
 import { environment } from "../../../environments/environment";
+import { NAVIGATOR_TOKEN } from "../../utils/di-tokens";
 
 /**
  * This service initializes the remote DB and manages the sync between the local and remote DB.
@@ -36,6 +37,7 @@ export class SyncService {
     private database: Database,
     private authService: KeycloakAuthService,
     private syncStateSubject: SyncStateSubject,
+    @Inject(NAVIGATOR_TOKEN) private navigator: Navigator,
   ) {
     this.remoteDatabase = new PouchDatabase(this.authService);
 
@@ -89,6 +91,12 @@ export class SyncService {
    * Execute a (one-time) sync between the local and server database.
    */
   sync(): Promise<SyncResult> {
+    if (!this.navigator.onLine) {
+      Logging.debug("Not syncing because offline");
+      this.syncStateSubject.next(SyncState.UNSYNCED);
+      return Promise.resolve({});
+    }
+
     this.syncStateSubject.next(SyncState.STARTED);
 
     return this.localDB