NestJS – Stripe Payment

NestJS

Stripe Payment Integration

Integrating Stripe for processing payments and handling webhooks in NestJS.

Stripe Service: Service for initializing Stripe and creating a payment intent.

📄payment.service.ts
typescript

import { Injectable, ConfigService } from '@nestjs/common';
import Stripe from 'stripe';

@Injectable()
export class PaymentService {
  private stripe: Stripe;

  constructor(private configService: ConfigService) {
    // Initialize Stripe with the secret key
    this.stripe = new Stripe(this.configService.get<string>('STRIPE_SECRET_KEY'), {
      apiVersion: '2023-10-16', // Use the latest supported API version
    });
  }

  async createPaymentIntent(amount: number, currency: string = 'usd') {
    try {
      const paymentIntent = await this.stripe.paymentIntents.create({
        amount: amount * 100, // Stripe expects amount in cents
        currency,
        automatic_payment_methods: {
          enabled: true,
        },
      });

      return {
        clientSecret: paymentIntent.client_secret,
      };
    } catch (error) {
      throw new Error(`Payment processing failed: ${error.message}`);
    }
  }

  constructWebhookEvent(payload: Buffer, signature: string) {
    const webhookSecret = this.configService.get<string>('STRIPE_WEBHOOK_SECRET');
    return this.stripe.webhooks.constructEvent(payload, signature, webhookSecret);
  }
}

Payment Controller: Endpoints for initiating payments and receiving Stripe webhook events.

📄payment.controller.ts
typescript

import { Controller, Post, Body, Req, Headers, RawBodyRequest, BadRequestException } from '@nestjs/common';
import { PaymentService } from './payment.service';

@Controller('payment')
export class PaymentController {
  constructor(private readonly paymentService: PaymentService) {}

  @Post('create-intent')
  async createPaymentIntent(@Body() body: { amount: number; currency?: string }) {
    return await this.paymentService.createPaymentIntent(body.amount, body.currency);
  }

  @Post('webhook')
  async handleWebhook(
    @Headers('stripe-signature') signature: string,
    @Req() req: RawBodyRequest<Request>,
  ) {
    if (!signature) {
      throw new BadRequestException('Missing stripe-signature header');
    }

    try {
      // Must use raw body for webhook signature verification
      const event = this.paymentService.constructWebhookEvent(req.rawBody, signature);

      // Handle the event
      switch (event.type) {
        case 'payment_intent.succeeded':
          const paymentIntent = event.data.object;
          console.log(`PaymentIntent for ${paymentIntent.amount} was successful!`);
          // Fulfill order, update database, etc.
          break;
        case 'payment_intent.payment_failed':
          console.log('Payment failed!');
          break;
        default:
          console.log(`Unhandled event type ${event.type}`);
      }

      return { received: true };
    } catch (err) {
      throw new BadRequestException(`Webhook Error: ${err.message}`);
    }
  }
}