Phonepe Integration in Node And React

                                        # Environment variables for PhonePe Payment Gateway

PORT=8000
PHONEPE_MERCHANT_ID=TESTMERCHANTUAT
PHONEPE_SALT_KEY=bb7d9e93-0759-49e1-a6b3-4b664668d076
PHONEPE_SALT_INDEX=1
PROJECT_URL=http://localhost:8000/payment-status
PROJECT_STATUS_URL=http://localhost:8000/payment-status
PROJECT_SUCCESS_URL=http://localhost:8000/status/success
PROJECT_FAILURE_URL=http://localhost:8000/status/failed
PHONEPE_API_URL=https://api-preprod.phonepe.com/apis/pg-sandbox/pg/v1/pay     # For production, use https://api.phonepe.com/apis/hermes/pg/v1/pay
PHONEPE_STATUS_URL=https://api
                                    

                                        {
  "phone": "9999999999",
  "amount": 100
}
                                    

                                        {
  "success": true,
  "message": "Payment initiated",
  "redirectUrl": "https://mercury-uat.phonepe.com/pay"
}
                                    

                                        import express from "express";
import dotenv from "dotenv";
import crypto from "crypto";
import { v4 as uuidv4 } from "uuid";
import axios from "axios";
import cors from "cors";

dotenv.config();

const app = express();
const port = process.env.PORT || 8080;

// Load environment variables
const {
 PHONEPE_MERCHANT_ID,
 PHONEPE_SALT_KEY,
 PHONEPE_SALT_INDEX,
 REDIRECT_URL,
 FRONTEND_SUCCESS_URL,
 FRONTEND_FAILURE_URL,
 PHONEPE_BASE_URL,
 PHONEPE_STATUS_URL,
} = process.env;

app.use(cors());
app.use(express.json());
app.use(express.urlencoded({ extended: true }));

// Root Route
app.get("/", (req, res) => {
 res.send("PhonePe Payment Gateway API is running.");
});

/**
* Function to generate a checksum (SHA256 hash)
*/
const generateChecksum = (payload, endpoint) => {
 const stringToHash = payload + endpoint + PHONEPE_SALT_KEY;
 const sha256 = crypto.createHash("sha256").update(stringToHash).digest("hex");
 return `${sha256}###${PHONEPE_SALT_INDEX}`;
};

/**
* Initialize Payment API
* Endpoint: POST /initialize-payment
*/
app.post("/initialize-payment", async (req, res) => {
 try {
   const { phone, amount } = req.body;
   if (!phone || !amount) {
     return res
       .status(400)
       .json({ success: false, message: "Invalid request parameters" });
   }

   const transactionId = uuidv4();

   const paymentPayload = {
     merchantId: PHONEPE_MERCHANT_ID,
     merchantUserId: "1",
     mobileNumber: phone,
     amount: Number(amount) * 100, // Convert to paisa
     merchantTransactionId: transactionId,
     redirectUrl: `${REDIRECT_URL}?transactionId=${transactionId}`,
     redirectMode: "POST",
     paymentInstrument: { type: "PAY_PAGE" },
   };

   const payload = Buffer.from(JSON.stringify(paymentPayload)).toString(
     "base64"
   );
   const checksum = generateChecksum(payload, "/pg/v1/pay");

   const response = await axios.post(
     PHONEPE_BASE_URL,
     { request: payload },
     {
       headers: {
         "Content-Type": "application/json",
         "X-VERIFY": checksum,
         "X-MERCHANT-ID": PHONEPE_MERCHANT_ID,
       },
     }
   );

   return res.status(200).json({
     success: true,
     message: "Payment initiated",
     redirectUrl: response.data.data.instrumentResponse.redirectInfo.url,
   });
 } catch (error) {
   console.error("Payment Initialization Error:", error);
   return res.status(500).json({
     success: false,
     message: "Payment initialization failed",
     error: error.message,
   });
 }
});

/**
* Verify Payment Status API
* Endpoint: POST /verify-status
*/
app.post("/verify-status", async (req, res) => {
 try {
   const { transactionId } = req.query;
   if (!transactionId) {
     return res
       .status(400)
       .json({ success: false, message: "Transaction ID is required" });
   }

   const statusUrl = `${PHONEPE_STATUS_URL}/${PHONEPE_MERCHANT_ID}/${transactionId}`;
   const checksum = generateChecksum(
     "",
     `/pg/v1/status/${PHONEPE_MERCHANT_ID}/${transactionId}`
   );

   const response = await axios.get(statusUrl, {
     headers: {
       "Content-Type": "application/json",
       "X-VERIFY": checksum,
     },
   });

   const paymentStatus = response.data.success
     ? FRONTEND_SUCCESS_URL
     : FRONTEND_FAILURE_URL;
   return res.redirect(paymentStatus);
 } catch (error) {
   console.error("Payment Status Verification Error:", error);
   return res.redirect(FRONTEND_FAILURE_URL);
 }
});

// Start the server
app.listen(port, () => {
 console.log(`Server running on port ${port}`);
});