add dtos and validation pipes

Author: javinchua

project/apps/api-gateway/package.json

@@ -20,6 +20,8 @@
     "test:e2e": "jest --config ./test/jest-e2e.json"
   },
   "dependencies": {
+    "@repo/pipes": "workspace:*",
+    "@repo/dtos": "workspace:*",
     "@nestjs/common": "^10.0.0",
     "@nestjs/core": "^10.0.0",
     "@nestjs/microservices": "^10.4.3",

project/apps/api-gateway/src/filters/rpc-exception.filter.ts

@@ -0,0 +1,14 @@
+import { ArgumentsHost, Catch, ExceptionFilter } from '@nestjs/common';
+import { RpcException } from '@nestjs/microservices';
+import { Response } from 'express';
+
+@Catch(RpcException)
+export class RpcExceptionFilter implements ExceptionFilter {
+  catch(exception: RpcException, host: ArgumentsHost) {
+    const error: any = exception.getError();
+    const ctx = host.switchToHttp();
+    const response = ctx.getResponse<Response>();
+
+    response.status(error.statusCode).json(error);
+  }
+}

project/apps/api-gateway/src/interceptors/rpc-exception.interceptor.ts

@@ -0,0 +1,24 @@
+import {
+  Injectable,
+  NestInterceptor,
+  ExecutionContext,
+  CallHandler,
+} from '@nestjs/common';
+import { Observable, throwError } from 'rxjs';
+import { catchError } from 'rxjs/operators';
+import { RpcException } from '@nestjs/microservices';
+
+@Injectable()
+export class RpcExceptionInterceptor implements NestInterceptor {
+  intercept(context: ExecutionContext, next: CallHandler): Observable<any> {
+    return next.handle().pipe(
+      catchError((error) => {
+        if (error.response) {
+          // This is likely an RPC error
+          return throwError(() => new RpcException(error.response));
+        }
+        return throwError(() => error);
+      }),
+    );
+  }
+}

project/apps/api-gateway/src/main.ts

@@ -1,8 +1,12 @@
 import { NestFactory } from '@nestjs/core';
 import { ApiGatewayModule } from './api-gateway.module';
+import { RpcExceptionFilter } from './filters/rpc-exception.filter';
+import { RpcExceptionInterceptor } from './interceptors/rpc-exception.interceptor';
 
 async function bootstrap() {
   const app = await NestFactory.create(ApiGatewayModule);
+  app.useGlobalFilters(new RpcExceptionFilter());
+  app.useGlobalInterceptors(new RpcExceptionInterceptor());
   await app.listen(4000);
 }
 bootstrap();

project/apps/api-gateway/src/questions/questions.controller.ts

@@ -1,8 +1,7 @@
 // apps/backend/api-gateway/src/questions/questions.controller.ts
 
-import { Controller, Get, Param, Inject } from '@nestjs/common';
+import { Controller, Get, Param, Inject, Body, Post } from '@nestjs/common';
 import { ClientProxy } from '@nestjs/microservices';
-
 @Controller('questions')
 export class QuestionsController {
   constructor(
@@ -14,4 +13,12 @@ export class QuestionsController {
   async getQuestionById(@Param('id') id: string) {
     return this.questionsServiceClient.send({ cmd: 'get_question' }, id);
   }
+
+  @Post()
+  async createQuestion(@Body() createQuestionDto: any) {
+    return this.questionsServiceClient.send(
+      { cmd: 'create_question' },
+      createQuestionDto,
+    );
+  }
 }

project/apps/questions-service/package.json

@@ -20,6 +20,8 @@
     "test:e2e": "jest --config ./test/jest-e2e.json"
   },
   "dependencies": {
+    "@repo/pipes": "workspace:*",
+    "@repo/dtos": "workspace:*",
     "@nestjs/common": "^10.0.0",
     "@nestjs/core": "^10.0.0",
     "@nestjs/microservices": "^10.4.3",

project/apps/questions-service/src/questions.controller.ts

@@ -1,7 +1,8 @@
-import { Controller } from '@nestjs/common';
-import { MessagePattern } from '@nestjs/microservices';
+import { Controller, UsePipes } from '@nestjs/common';
+import { MessagePattern, Payload } from '@nestjs/microservices';
 import { QuestionsService } from './questions.service';
-
+import { ZodValidationPipe } from '@repo/pipes/zod-validation-pipe.pipe';
+import { CreateQuestionDto, createQuestionSchema } from '@repo/dtos/questions';
 @Controller()
 export class QuestionsController {
   constructor(private readonly questionsService: QuestionsService) {}
@@ -10,4 +11,10 @@ export class QuestionsController {
   getQuestion(id: string) {
     return this.questionsService.findById(id);
   }
+
+  @MessagePattern({ cmd: 'create_question' })
+  @UsePipes(new ZodValidationPipe(createQuestionSchema))
+  async create(@Payload() createQuestionDto: CreateQuestionDto) {
+    return createQuestionDto;
+  }
 }

project/packages/dtos/package.json

@@ -0,0 +1,47 @@
+{
+  "name": "@repo/dtos",
+  "version": "0.0.0",
+  "private": true,
+  "license": "MIT",
+  "scripts": {
+    "dev": "pnpm build --watch",
+    "build": "tsc -b -v",
+    "lint": "eslint \"{src,apps,libs,test}/**/*.ts\""
+  },
+  "main": "./dist/index.js",
+  "types": "./dist/index.d.ts",
+  "files": [
+    "./dist/**"
+  ],
+  "publishConfig": {
+    "access": "public"
+  },
+  "typesVersions": {
+    "*": {
+      "*": [
+        "src/*"
+      ]
+    }
+  },
+  "exports": {
+    ".": {
+      "import": "./dist/index.js",
+      "require": "./dist/index.js"
+    },
+    "./*": {
+      "import": "./dist/*.js",
+      "require": "./dist/*.js"
+    }
+  },
+  "dependencies": {
+    "zod": "^3.23.8"
+  },
+  "devDependencies": {
+    "@repo/eslint-config": "workspace:*",
+    "@repo/typescript-config": "workspace:*",
+    "@types/node": "^20.3.1",
+    "ts-loader": "^9.4.3",
+    "ts-node": "^10.9.1",
+    "typescript": "^5.1.3"
+  }
+}

project/packages/dtos/src/questions.ts

@@ -0,0 +1,12 @@
+import { z } from "zod";
+
+export const createQuestionSchema = z
+  .object({
+    title: z.string().min(1),
+    description: z.string().min(1),
+    category: z.string().min(1),
+    complexity: z.number().min(1).max(5),
+  })
+  .required();
+
+export type CreateQuestionDto = z.infer<typeof createQuestionSchema>;

project/packages/dtos/tsconfig.json

@@ -0,0 +1,9 @@
+{
+  "extends": "@repo/typescript-config/base.json",
+  "compilerOptions": {
+    "outDir": "dist",
+    "rootDir": "src"
+  },
+  "include": ["src"],
+  "exclude": ["node_modules", "dist"]
+}