fix: do not fetch remote configuration if offline

Closes #206

frontend/app/src/app/modules/config/config.provider.spec.ts

@@ -24,13 +24,17 @@ import {
 } from './errors';
 import {NGXLogger} from 'ngx-logger';
 import {sampleIndexResponse} from '../../_helpers/data/sample-configuration';
+import {BehaviorSubject} from 'rxjs';
+import {InternetConnectionService} from '../../util/internet-connection.service';
 
 describe('ConfigProvider', () => {
+  let internetConnectionServiceMock: {offline$: BehaviorSubject<boolean>};
   let configProvider: ConfigProvider;
   let storageProviderSpy: jasmine.SpyObj<StorageProvider>;
   let ngxLogger: jasmine.SpyObj<NGXLogger>;
 
   beforeEach(() => {
+    internetConnectionServiceMock = {offline$: new BehaviorSubject<boolean>(false)};
     storageProviderSpy = jasmine.createSpyObj('StorageProvider', ['init', 'get', 'has', 'put']);
     const webHttpClientMethodSpy = jasmine.createSpyObj('StAppsWebHttpClient', ['request']);
     ngxLogger = jasmine.createSpyObj('NGXLogger', ['log', 'error', 'warn']);
@@ -51,6 +55,10 @@ describe('ConfigProvider', () => {
           provide: NGXLogger,
           useValue: ngxLogger,
         },
+        {
+          provide: InternetConnectionService,
+          useValue: internetConnectionServiceMock,
+        },
       ],
     });
 
@@ -75,6 +83,22 @@ describe('ConfigProvider', () => {
     expect(error).toEqual(new ConfigFetchError());
   });
 
+  it('should throw device offline error when offline', async () => {
+    // eslint-disable-next-line unicorn/error-message
+    let error = new Error('');
+    // eslint-disable-next-line @typescript-eslint/ban-ts-comment
+    // @ts-ignore
+    internetConnectionServiceMock.offline$ = new BehaviorSubject<boolean>(true);
+
+    try {
+      await configProvider.fetch();
+    } catch (error_) {
+      error = error_ as Error;
+      expect(error).toBeInstanceOf(ConfigFetchError);
+      expect(error.message).toContain('Device is offline.');
+    }
+  });
+
   it('should init from remote and saved config not available', async () => {
     storageProviderSpy.has.and.returnValue(Promise.resolve(false));
     spyOn(configProvider.client, 'handshake').and.returnValue(Promise.resolve(sampleIndexResponse));

frontend/app/src/app/modules/config/config.provider.ts

@@ -27,6 +27,8 @@ import {
   SavedConfigNotAvailable,
   WrongConfigVersionInStorage,
 } from './errors';
+import {InternetConnectionService} from '../../util/internet-connection.service';
+import {firstValueFrom} from 'rxjs';
 
 /**
  * Key to store config in storage module
@@ -72,6 +74,7 @@ export class ConfigProvider {
     private readonly storageProvider: StorageProvider,
     swHttpClient: StAppsWebHttpClient,
     private readonly logger: NGXLogger,
+    private readonly internetConnectionService: InternetConnectionService,
   ) {
     console.log('config init');
     this.client = new Client(swHttpClient, environment.backend_url, environment.backend_version);
@@ -82,9 +85,15 @@ export class ConfigProvider {
    */
   async fetch(): Promise<SCIndexResponse> {
     try {
+      const isOffline = await firstValueFrom(this.internetConnectionService.offline$);
+      if (isOffline) {
+        throw new Error('Device is offline.');
+      } else {
         return await this.client.handshake(this.scVersion);
-    } catch {
+      }
-      throw new ConfigFetchError();
+    } catch (error) {
+      const error_ = error instanceof Error ? new ConfigFetchError(error.message) : new ConfigFetchError();
+      throw error_;
     }
   }
 

frontend/app/src/app/modules/config/errors.ts

@@ -19,8 +19,10 @@ import {AppError} from '../../_helpers/errors';
  * Error that is thrown when fetching from backend fails
  */
 export class ConfigFetchError extends AppError {
-  constructor() {
+  constructor(reason?: string) {
-    super('ConfigFetchError', 'App configuration could not be fetched!');
+    const defaultMessage = 'App configuration could not be fetched!';
+    const message = reason ? `${defaultMessage} ${reason}` : defaultMessage;
+    super('ConfigFetchError', message);
   }
 }