feat(core): middleware should run once for one request. (nestjs#1628)

integration/hello-world/e2e/middleware-execute-once.spec.ts

@@ -0,0 +1,68 @@
+import {
+  Controller,
+  Get,
+  INestApplication,
+  Injectable,
+  MiddlewareConsumer,
+  NestMiddleware,
+  Module,
+} from '@nestjs/common';
+import { Test } from '../../../packages/testing';
+import * as request from 'supertest';
+import { expect } from 'chai';
+
+let number: number = 0;
+
+@Injectable()
+class Middleware implements NestMiddleware {
+  use(req, res, next) {
+    number++;
+    next();
+  }
+}
+
+@Controller('/a')
+class TestController {
+  @Get('/test')
+  testA() {
+    return '';
+  }
+  @Get('/:id')
+  testB() {
+    return '';
+  }
+}
+
+@Module({
+  controllers: [TestController],
+})
+class TestModule {
+  configure(consumer: MiddlewareConsumer) {
+    consumer.apply(Middleware).forRoutes(TestController);
+  }
+}
+
+describe('Middleware (execution once)', () => {
+  let app: INestApplication;
+
+  beforeEach(async () => {
+    app = (await Test.createTestingModule({
+      imports: [TestModule],
+    }).compile()).createNestApplication();
+
+    await app.init();
+  });
+
+  it(`forRoutes(TestController) should execute middleware once`, () => {
+    return request(app.getHttpServer())
+      .get('/a/test')
+      .expect(200)
+      .then(() => {
+        expect(number).to.be.eq(1);
+      });
+  });
+
+  afterEach(async () => {
+    await app.close();
+  });
+});

packages/core/middleware/middleware-module.ts

@@ -256,7 +256,16 @@ export class MiddlewareModule {
       undefined,
       contextId,
     );
-    const middleware = instance.use.bind(instance);
+    const middleware = (req, res, next) => {
+      const stack: Set<NestMiddleware> = req.stack || new Set();
+      if (!stack.has(instance)) {
+        stack.add(instance);
+        req.stack = stack;
+        instance.use.apply(instance, [req, res, next]);
+      } else {
+        next();
+      }
+    };
     return this.routerProxy.createProxy(middleware, exceptionsHandler);
   }