Remove Callback module, service, and controller; add callback handlin…

…g in MpesaExpressController with Redis integration for payment status updates

src/app.module.ts

@@ -1,14 +1,12 @@
 import { Module, MiddlewareConsumer, NestModule } from '@nestjs/common';
 import { LoggerMiddleware } from './logger/logger.middleware';
 import { MpesaExpressModule } from './mpesa-express/mpesa-express.module';
-import { CallbackModule } from './callback/callback.module';
 import { ConfigModule, ConfigService } from '@nestjs/config'; 
 import { RedisModule } from '@liaoliaots/nestjs-redis';
 
 
 @Module({
     imports: [MpesaExpressModule,
-        CallbackModule,
         ConfigModule.forRoot({ isGlobal: true }),
         RedisModule.forRootAsync({
             useFactory: (configService: ConfigService) => configService.get('REDIS_URL'),

src/mpesa-express/mpesa-express.controller.ts

@@ -1,13 +1,49 @@
-import { Controller, Get, Post, Body, Patch, Param, Delete } from '@nestjs/common';
+import { Controller, Get, Post, Body, Patch, Param, Delete, Logger } from '@nestjs/common';
 import { MpesaExpressService } from './mpesa-express.service';
 import { CreateMpesaExpressDto } from './dto/create-mpesa-express.dto';
+import Redis from 'ioredis';
+import { RedisService } from '@liaoliaots/nestjs-redis';
 
 @Controller('mpesa')
 export class MpesaExpressController {
-    constructor(private readonly mpesaExpressService: MpesaExpressService) {}
+    private readonly redis: Redis | null;
+    private logger = new Logger('MpesaExpressController');
+    constructor(
+        private mpesaExpressService: MpesaExpressService,
+        private readonly redisService: RedisService
+    ) {}
 
     @Post('/stkpush')
     create(@Body() createMpesaExpressDto: CreateMpesaExpressDto) {
         return this.mpesaExpressService.stkPush(createMpesaExpressDto);
     }
+
+    @Post('/callback')
+    async handleCallback(@Body() callBackData: any) {
+        this.logger.debug(`Callback data: ${JSON.stringify(callBackData)}`);
+        const redisClient = this.redisService.getOrThrow();
+
+        const { Body: { stkCallback } } = callBackData;
+
+        const { MerchantRequestID, CheckoutRequestID, ResultCode, ResultDesc } = stkCallback;
+
+        const payment = await redisClient.get(MerchantRequestID);
+        // if (!payment || payment === null || payment === undefined) {
+        //     this.logger.error('Payment not found, was it cached?');
+        // }
+
+        if (payment) {
+            this.logger.debug(`Payment found: ${payment}`);
+            const parsedData = JSON.parse(payment);
+
+            if(ResultCode === 0) {
+                parsedData.status = 'COMPLETED';
+            } else {
+                parsedData.status = 'FAILED';
+            }
+            await redisClient.set(MerchantRequestID, JSON.stringify(parsedData));
+        } else {
+            this.logger.error('Payment not found, was it cached?');
+        }
+    }
 }

src/mpesa-express/mpesa-express.service.ts

@@ -16,6 +16,7 @@ export class MpesaExpressService {
 
     private readonly redis: Redis | null;
     private logger = new Logger('MpesaExpressService');
+
 
     private async generateTimestamp(): Promise<string> {
         const date = new Date();
@@ -27,8 +28,33 @@ export class MpesaExpressService {
              ('0' + date.getSeconds()).slice(-2);
     }
 
+
+    async validateDto(createMpesaExpressDto: CreateMpesaExpressDto): Promise<void> {
+        const obeysPhoneNum = createMpesaExpressDto.phoneNum.match(/^2547\d{8}$/);
+        if (!obeysPhoneNum) {
+            this.logger.warn("The phone number does not obey the format");
+            throw new HttpException('Phone number must be in the format 2547XXXXXXXX"', 400);
+        }
+
+        const obeysAccountRef = createMpesaExpressDto.accountRef.match(/^[a-zA-Z0-9]{1,12}$/);
+        if (!obeysAccountRef) {
+            this.logger.warn("The account reference does not obey the format");
+            throw new HttpException('Account reference must be alphanumeric and not more than 12 characters', 400);
+        }
+
+        const obeysAmount = createMpesaExpressDto.amount > 0;
+        if (!obeysAmount) {
+            this.logger.warn("The amount does not obey the format");
+            throw new HttpException('Amount must be greater than 0', 400);
+        }
+
+        return;
+    }
 
     async stkPush(createMpesaExpressDto: CreateMpesaExpressDto): Promise<void> {
+
+        await this.validateDto(createMpesaExpressDto);
+
         const shortcode = "174379";
         const passkey = this.configService.get('PASS_KEY');