feat: makes the endpoint idempotent

apps/nestjs-rabbitmq-example/src/credit-card/credit-card.module.ts

@@ -1,9 +1,10 @@
 import { Module } from '@nestjs/common';
 import { CreateChargeController } from './presentation/controllers/create-charge.controller';
 import { CreditCardModule } from '@libs/credit-card/credit-card.module';
+import { IdempotencyModule } from '../idempotency/idempotency.module';
 
 @Module({
-  imports: [CreditCardModule],
+  imports: [CreditCardModule, IdempotencyModule],
   controllers: [CreateChargeController],
 })
 export class CreditCardApiModule {}

apps/nestjs-rabbitmq-example/src/credit-card/presentation/controllers/create-charge.controller.ts

@@ -1,8 +1,17 @@
-import { CreateChargeUseCase } from '@libs/credit-card/app/use-cases/create-charge.use-case';
-import { CreateChargeInputProps } from '@libs/credit-card/domain/contracts/psp-service.interface';
-import { ICreateChargeUseCase } from '@libs/credit-card/domain/use-cases/create-charge.use-case';
-import { Body, Controller, Inject, Post } from '@nestjs/common';
+import { IdempotencyKeyInterceptor } from '@api/idempotency/infra/interceptors';
+import { CreateChargeUseCase } from '@libs/credit-card/app/use-cases';
+import { CreateChargeInputProps } from '@libs/credit-card/domain/contracts';
+import { ICreateChargeUseCase } from '@libs/credit-card/domain/use-cases';
 
+import {
+  Body,
+  Controller,
+  Inject,
+  Post,
+  UseInterceptors,
+} from '@nestjs/common';
+
+@UseInterceptors(IdempotencyKeyInterceptor)
 @Controller('charge')
 export class CreateChargeController {
   constructor(

apps/nestjs-rabbitmq-example/src/idempotency/domain/models/idempotency.model.ts

@@ -0,0 +1,4 @@
+export type IdempotencyModel = {
+  key: string;
+  response: any;
+};

apps/nestjs-rabbitmq-example/src/idempotency/domain/repositories/idempotency.repository.ts

@@ -0,0 +1,7 @@
+import { IdempotencyModel } from '../models/idempotency.model';
+
+export interface IIdempotencyRepository {
+  find(key: string): Promise<IdempotencyModel | undefined>;
+  preSave(key: string): Promise<void>;
+  update(key: string, response: any): Promise<void>;
+}

apps/nestjs-rabbitmq-example/src/idempotency/domain/repositories/index.ts

@@ -0,0 +1 @@
+export * from './idempotency.repository';

apps/nestjs-rabbitmq-example/src/idempotency/idempotency.module.ts

@@ -0,0 +1,9 @@
+import { Module } from '@nestjs/common';
+import { Redis } from '../infra/redis/redis';
+import { IdempotencyRepository } from './infra/repositories/idempotency.repository';
+
+@Module({
+  providers: [Redis, IdempotencyRepository],
+  exports: [IdempotencyRepository],
+})
+export class IdempotencyModule {}

apps/nestjs-rabbitmq-example/src/idempotency/infra/interceptors/idempotency-key.interceptor.ts

@@ -0,0 +1,64 @@
+import {
+  Injectable,
+  NestInterceptor,
+  ExecutionContext,
+  CallHandler,
+  BadRequestException,
+  Inject,
+} from '@nestjs/common';
+import { Observable, of } from 'rxjs';
+import { tap } from 'rxjs/operators';
+import { IdempotencyRepository } from '../repositories';
+import { IIdempotencyRepository } from '@api/idempotency/domain/repositories';
+
+@Injectable()
+export class IdempotencyKeyInterceptor implements NestInterceptor {
+  constructor(
+    @Inject(IdempotencyRepository)
+    private readonly idempotencyRepository: IIdempotencyRepository,
+  ) {}
+
+  async intercept(
+    context: ExecutionContext,
+    next: CallHandler,
+  ): Promise<Observable<any>> {
+    const ctx = context.switchToHttp();
+    const request = ctx.getRequest<Request>();
+    const idempotencyKey = request.headers['x-idempotency-key'];
+
+    if (!idempotencyKey) {
+      throw new BadRequestException(
+        "Header 'x-idempotency-key' is required for this request.",
+      );
+    }
+
+    if (!this.isValidUUID(idempotencyKey)) {
+      throw new BadRequestException(
+        "Header 'x-idempotency-key' must be a UUID.",
+      );
+    }
+
+    const idempotencyModel = await this.idempotencyRepository.find(
+      idempotencyKey,
+    );
+
+    if (idempotencyModel) {
+      return of(idempotencyModel.response);
+    }
+
+    await this.idempotencyRepository.preSave(idempotencyKey);
+
+    return next.handle().pipe(
+      tap(async (data) => {
+        await this.idempotencyRepository.update(idempotencyKey, data);
+        return data;
+      }),
+    );
+  }
+
+  private isValidUUID(uuid: string) {
+    const uuidRegex =
+      /(?:^[a-f0-9]{8}-[a-f0-9]{4}-4[a-f0-9]{3}-[a-f0-9]{4}-[a-f0-9]{12}$)|(?:^0{8}-0{4}-0{4}-0{4}-0{12}$)/u;
+    return uuidRegex.test(uuid);
+  }
+}

apps/nestjs-rabbitmq-example/src/idempotency/infra/interceptors/index.ts

@@ -0,0 +1 @@
+export * from './idempotency-key.interceptor';

apps/nestjs-rabbitmq-example/src/idempotency/infra/repositories/idempotency.repository.ts

@@ -0,0 +1,24 @@
+import { Redis } from 'apps/nestjs-rabbitmq-example/src/infra/redis/redis';
+import { IIdempotencyRepository } from '../../domain/repositories/idempotency.repository';
+import { Injectable } from '@nestjs/common';
+import { IdempotencyModel } from '../../domain/models/idempotency.model';
+
+@Injectable()
+export class IdempotencyRepository implements IIdempotencyRepository {
+  constructor(private readonly redis: Redis) {}
+
+  async find(key: string): Promise<IdempotencyModel | undefined> {
+    const data = await this.redis.get(key);
+    if (data) {
+      return { key, response: data };
+    }
+  }
+
+  async preSave(key: string): Promise<void> {
+    await this.redis.set(key);
+  }
+
+  async update(key: string, response: any): Promise<void> {
+    await this.redis.set(key, response);
+  }
+}

apps/nestjs-rabbitmq-example/src/idempotency/infra/repositories/index.ts

@@ -0,0 +1 @@
+export * from './idempotency.repository';

apps/nestjs-rabbitmq-example/src/infra/redis/redis.ts

@@ -0,0 +1,14 @@
+import { Injectable } from '@nestjs/common';
+
+@Injectable()
+export class Redis {
+  private static data = new Map<string, any>();
+
+  async get(key: string) {
+    return Promise.resolve(Redis.data.get(key));
+  }
+
+  async set(key: string, value?: any) {
+    Promise.resolve(Redis.data.set(key, value));
+  }
+}

libs/credit-card/src/app/use-cases/index.ts

@@ -0,0 +1 @@
+export * from './create-charge.use-case';

libs/credit-card/src/domain/contracts/index.ts

@@ -0,0 +1,2 @@
+export * from './psp-service.interface';
+export * from './publisher.interface';

libs/credit-card/src/domain/entities/index.ts

@@ -0,0 +1 @@
+export * from './credit-card-charge.entity';

libs/credit-card/src/domain/use-cases/index.ts

@@ -0,0 +1 @@
+export * from './create-charge.use-case';

libs/credit-card/src/infra/psp/pagarme/index.ts

@@ -0,0 +1 @@
+export * from './pagarme.service';

libs/credit-card/src/infra/rmq/publisher/index.ts

@@ -0,0 +1 @@
+export * from './create-charge.publisher';

nest-cli.json

@@ -4,7 +4,7 @@
   "sourceRoot": "apps/nestjs-rabbitmq-example/src",
   "compilerOptions": {
     "deleteOutDir": true,
-    "webpack": true,
+    "webpack": false,
     "tsConfigPath": "apps/nestjs-rabbitmq-example/tsconfig.app.json"
   },
   "monorepo": true,

tsconfig.json

@@ -20,6 +20,9 @@
     "paths": {
       "@libs/credit-card/*": [
         "libs/credit-card/src/*"
+      ],
+      "@api/*": [
+        "apps/nestjs-rabbitmq-example/src/*"
       ]
     }
   }