feat: add API endpoints config and feature flags for endpoints

Author: gultyayev

src/app/app.module.ts

@@ -14,6 +14,8 @@ import { ProductsModule } from './products/products.module';
 import { HttpClientModule } from '@angular/common/http';
 import { MatBadgeModule } from '@angular/material/badge';
 import { CartModule } from './cart/cart.module';
+import { CONFIG_TOKEN } from './core/injection-tokens/config.token';
+import { environment } from '../environments/environment';
 
 @NgModule({
   declarations: [AppComponent, HeaderComponent],
@@ -31,7 +33,12 @@ import { CartModule } from './cart/cart.module';
     HttpClientModule,
     MatBadgeModule,
   ],
-  providers: [],
+  providers: [
+    {
+      provide: CONFIG_TOKEN,
+      useValue: environment,
+    },
+  ],
   bootstrap: [AppComponent],
 })
 export class AppModule {}

src/app/core/api.service.spec.ts

@@ -0,0 +1,16 @@
+import { TestBed } from '@angular/core/testing';
+
+import { ApiService } from './api.service';
+
+describe('ApiService', () => {
+  let service: ApiService;
+
+  beforeEach(() => {
+    TestBed.configureTestingModule({});
+    service = TestBed.inject(ApiService);
+  });
+
+  it('should be created', () => {
+    expect(service).toBeTruthy();
+  });
+});

src/app/core/api.service.ts

@@ -0,0 +1,26 @@
+import { Injectable, Injector } from '@angular/core';
+import { ApiEndpoint, Config } from '../../environments/config.interface';
+import { CONFIG_TOKEN } from './injection-tokens/config.token';
+import { Location } from '@angular/common';
+import { HttpClient } from '@angular/common/http';
+
+/** Base class for services working with APIs */
+@Injectable()
+export abstract class ApiService {
+  protected readonly config: Config;
+  protected readonly http: HttpClient;
+
+  protected constructor(protected readonly injector: Injector) {
+    this.config = injector.get(CONFIG_TOKEN);
+    this.http = injector.get(HttpClient);
+  }
+
+  endpointEnabled(api: ApiEndpoint): boolean {
+    return this.config.apiEndpointsEnabled[api];
+  }
+
+  /** Combines API endpoint and path into a single URL */
+  protected getUrl(api: ApiEndpoint, path: string): string {
+    return Location.joinWithSlash(this.config.apiEndpoints[api], path);
+  }
+}

src/app/core/injection-tokens/config.token.ts

@@ -0,0 +1,4 @@
+import { InjectionToken } from '@angular/core';
+import { Config } from '../../../environments/config.interface';
+
+export const CONFIG_TOKEN = new InjectionToken<Config>('CONFIG_TOKEN');

src/app/products/products.service.ts

@@ -1,17 +1,20 @@
 import { Injectable } from '@angular/core';
-import { HttpClient } from '@angular/common/http';
 import { Observable, of } from 'rxjs';
 import { Product } from './product.interface';
 import { map } from 'rxjs/operators';
+import { ApiService } from '../core/api.service';
 
 @Injectable({
   providedIn: 'root',
 })
-export class ProductsService {
-  constructor(private readonly http: HttpClient) {}
-
+export class ProductsService extends ApiService {
   getProducts(): Observable<Product[]> {
-    return this.http.get<Product[]>('/assets/products.json');
+    if (!this.endpointEnabled('bff')) {
+      return this.http.get<Product[]>('/assets/products.json');
+    }
+
+    const url = this.getUrl('bff', 'products');
+    return this.http.get<Product[]>(url);
   }
 
   getProductsForCheckout(ids: string[]): Observable<Product[]> {

src/environments/config.interface.ts

@@ -0,0 +1,7 @@
+export type ApiEndpoint = 'product' | 'order' | 'import' | 'bff' | 'cart';
+
+export interface Config {
+  production: boolean;
+  apiEndpoints: Record<ApiEndpoint, string>;
+  apiEndpointsEnabled: Record<ApiEndpoint, boolean>;
+}

src/environments/environment.prod.ts

@@ -1,3 +1,19 @@
-export const environment = {
+import { Config } from './config.interface';
+
+export const environment: Config = {
   production: true,
+  apiEndpoints: {
+    product: 'https://.execute-api.eu-west-1.amazonaws.com/dev',
+    order: 'https://.execute-api.eu-west-1.amazonaws.com/dev',
+    import: 'https://.execute-api.eu-west-1.amazonaws.com/dev',
+    bff: 'https://.execute-api.eu-west-1.amazonaws.com/dev',
+    cart: 'https://.execute-api.eu-west-1.amazonaws.com/dev',
+  },
+  apiEndpointsEnabled: {
+    product: false,
+    order: false,
+    import: false,
+    bff: false,
+    cart: false,
+  },
 };

src/environments/environment.ts

@@ -2,8 +2,24 @@
 // `ng build --prod` replaces `environment.ts` with `environment.prod.ts`.
 // The list of file replacements can be found in `angular.json`.
 
-export const environment = {
+import { Config } from './config.interface';
+
+export const environment: Config = {
   production: false,
+  apiEndpoints: {
+    product: 'https://.execute-api.eu-west-1.amazonaws.com/dev',
+    order: 'https://.execute-api.eu-west-1.amazonaws.com/dev',
+    import: 'https://.execute-api.eu-west-1.amazonaws.com/dev',
+    bff: 'https://.execute-api.eu-west-1.amazonaws.com/dev',
+    cart: 'https://.execute-api.eu-west-1.amazonaws.com/dev',
+  },
+  apiEndpointsEnabled: {
+    product: false,
+    order: false,
+    import: false,
+    bff: false,
+    cart: false,
+  },
 };
 
 /*