feat: added an interceptor for HTTP requests

lib/feature-toggle-header-request.interceptor.spec.ts

@@ -0,0 +1,35 @@
+import { Test, TestingModule } from '@nestjs/testing';
+import { FeatureToggleHeaderRequestInterceptor } from './feature-toggle-header-request.interceptor';
+import { FEATURE_TOGGLE_MODULE_OPTIONS } from './feature-toggle.constants';
+import { FeatureToggleService } from './feature-toggle.service';
+
+describe('FeatureToggleHeaderRequestInterceptor', () => {
+  let app: TestingModule;
+  let featureToggleHeaderRequestInterceptor: FeatureToggleHeaderRequestInterceptor;
+  beforeAll(async () => {
+    app = await Test.createTestingModule({
+      providers: [
+        {
+          provide: FeatureToggleService,
+          useClass: FeatureToggleService
+        },
+        {
+          provide: FeatureToggleHeaderRequestInterceptor,
+          useClass: FeatureToggleHeaderRequestInterceptor
+        },
+        {
+          provide: FEATURE_TOGGLE_MODULE_OPTIONS,
+          useValue: {}
+        }
+      ]
+    }).compile();
+
+    featureToggleHeaderRequestInterceptor =
+      app.get<FeatureToggleHeaderRequestInterceptor>(
+        FeatureToggleHeaderRequestInterceptor
+      );
+  });
+  it('should be defined', () => {
+    expect(featureToggleHeaderRequestInterceptor).toBeDefined();
+  });
+});

lib/feature-toggle-header-request.interceptor.ts

@@ -0,0 +1,41 @@
+import {
+  CallHandler,
+  ExecutionContext,
+  Injectable,
+  NestInterceptor
+} from '@nestjs/common';
+import { Observable } from 'rxjs';
+import { FeatureToggleService } from './feature-toggle.service';
+import { FeatureEntity } from './entities';
+
+@Injectable()
+export class FeatureToggleHeaderRequestInterceptor implements NestInterceptor {
+  constructor(private featureToggleService: FeatureToggleService) {}
+  async intercept(
+    context: ExecutionContext,
+    next: CallHandler
+  ): Promise<Observable<any>> {
+    const headers = context.switchToHttp().getRequest().headers;
+    Object.keys(headers)
+      .filter((key) =>
+        key.includes(
+          this.featureToggleService.getHttpContextConfig()
+            ?.keywordToBeSearchedInHeader ?? 'feature_'
+        )
+      )
+      .forEach(async (key) => {
+        const feature = (await this.featureToggleService.getFeature(
+          key.toUpperCase()
+        )) as FeatureEntity;
+
+        if (
+          typeof feature !== 'undefined' &&
+          feature.isAcceptHTTPRequestContext()
+        ) {
+          feature.setValue(!!parseInt(headers[key] as string));
+        }
+      });
+
+    return next.handle();
+  }
+}

lib/feature-toggle.module.ts

@@ -8,26 +8,37 @@ import { FeatureToggleService } from './feature-toggle.service';
 import { createFeatureToggleProvider } from './feature-toggle.providers';
 import { FEATURE_TOGGLE_MODULE_OPTIONS } from './feature-toggle.constants';
 import { FeatureToggleExpressMiddleware } from '.';
+import { FeatureToggleHeaderRequestInterceptor } from './feature-toggle-header-request.interceptor';
 
 @Module({
-  providers: [FeatureToggleService, {
-    provide: FeatureToggleExpressMiddleware,
-    useFactory: (FeatureToggleService: FeatureToggleService) => {
-      return new FeatureToggleExpressMiddleware(FeatureToggleService);
+  providers: [
+    FeatureToggleService,
+    {
+      provide: FeatureToggleExpressMiddleware,
+      useFactory: (FeatureToggleService: FeatureToggleService) => {
+        return new FeatureToggleExpressMiddleware(FeatureToggleService);
+      },
+      inject: [FeatureToggleService]
     },
-    inject: [FeatureToggleService]
-  }],
-  exports:[FeatureToggleService]
+    {
+      provide: 'APP_INTERCEPTOR',
+      scope: Scope.REQUEST,
+      useClass: FeatureToggleHeaderRequestInterceptor
+    }
+  ],
+  exports: [FeatureToggleService]
 })
 export class FeatureToggleModule {
   static register(options: FeatureToggleModuleOptions): DynamicModule {
     return {
       module: FeatureToggleModule,
       providers: createFeatureToggleProvider(options)
-    }
+    };
   }
 
-  static registerAsync(options: FeatureToggleModuleAsyncOptions): DynamicModule {
+  static registerAsync(
+    options: FeatureToggleModuleAsyncOptions
+  ): DynamicModule {
     return {
       module: FeatureToggleModule,
       imports: options.imports || [],
@@ -78,4 +89,4 @@ export class FeatureToggleModule {
       scope: Scope.REQUEST
     };
   }
-}
+}

package.json

@@ -26,7 +26,7 @@
     "@commitlint/config-angular": "13.1.0",
     "@nestjs/common": "8.0.6",
     "@nestjs/core": "8.0.6",
-    "@nestjs/testing": "8.0.6",
+    "@nestjs/testing": "^8.0.6",
     "@types/jest": "26.0.24",
     "@types/node": "14.17.12",
     "@typescript-eslint/eslint-plugin": "4.29.3",