Seamless UPI Integration Flow

{
  "merchant_data": {
    "merchant_id": 12345678,
    "merchant_access_code": "4a8c422e-928d-4f84-bfe8-27a09af66647",
    "unique_merchant_txn_id": "XYZ123",
    "merchant_return_url": "https://www.pinelabs.com"
  },
  "payment_data": {
    "amount_in_paisa": 800
  },
  "txn_data": {
    "navigation_mode": "7",
    "payment_mode": "10",
    "transaction_type": "1",
    "time_stamp": 157588000000
  }
}

import java.util.Base64;
import java.util.HashMap;
import java.util.LinkedHashMap;
import java.util.Map;
import java.util.stream.Collectors;
import com.google.gson.Gson;
import com.google.gson.GsonBuilder;

public class SignatureGenerator {
  private static Map < String, Object > clean(Map < String, Object > arr) {
    return arr.entrySet().stream()
      .filter(entry -> entry.getValue() != null && !entry.getValue().toString().isEmpty())
      .collect(Collectors.toMap(Map.Entry::getKey, Map.Entry::getValue));
  }
  public static void main(String[] args) {
    Map < String, Object > requestBody = new LinkedHashMap < > ();
    Map < String, Object > merchant_data = new LinkedHashMap < > ();
    merchant_data.put("merchant_id", "merchant_id");
    merchant_data.put("merchant_access_code", "merchant_access_code");
    merchant_data.put("unique_merchant_txn_id", "XYZ123");
    merchant_data.put("merchant_return_url", "whitelisted_merchant_return_url");
    requestBody.put("merchant_data", merchant_data);

    Map < String, Object > paymentDataObject = new LinkedHashMap < > ();
    paymentDataObject.put("amount_in_paisa", 100);
    requestBody.put("payment_data", paymentDataObject);
    Map < String, Object > txnObject = new LinkedHashMap < > ();
    txnObject.put("navigation_mode", "2");
    txnObject.put("payment_mode", "1,3,4,19,10,11,14");
    txnObject.put("transaction_type", "1");
    requestBody.put("txn_data", txnObject);

    Map < String, Object > requestBodyCleaned = clean(requestBody);
    Map < String, Object > mapStatus = new HashMap < > ();
    mapStatus.put("result", requestBodyCleaned);
    Gson gson = new GsonBuilder().disableHtmlEscaping().create();
    String jsonString2 = gson.toJson(requestBodyCleaned);
    jsonString2 = jsonString2.replace("\\/", "/");

    // Encoding JSON string to base64
    String base64Encoded = Base64.getEncoder().encodeToString(jsonString2.getBytes());

    System.out.println(base64Encoded);
  }
}

import java.io.UnsupportedEncodingException;
import java.math.BigInteger;
import java.security.InvalidKeyException;
import java.security.NoSuchAlgorithmException;
import javax.crypto.Mac;
import javax.crypto.spec.SecretKeySpec;
import javax.xml.bind.DatatypeConverter;

public class SignatureGenerator {

    public static String jsonHash(String request, String secret) throws NoSuchAlgorithmException, InvalidKeyException, IllegalStateException, UnsupportedEncodingException {
        SecretKeySpec secretKeySpec = new SecretKeySpec(DatatypeConverter.parseHexBinary(secret), "HmacSHA256");
        Mac mac = Mac.getInstance("HmacSHA256");
        mac.init(secretKeySpec);
        byte[] hmacBytes = mac.doFinal(request.getBytes("UTF-8"));
        String ss = String.format("%02x", new BigInteger(1, hmacBytes));
        return bytesToHex(hmacBytes).toUpperCase();
    }
    private static String bytesToHex(byte[] bytes) {
        StringBuilder result = new StringBuilder();
        for (byte b : bytes) {
            result.append(String.format("%02X", b));
        }
        return result.toString();
    }

    public static void main(String[] args) throws UnsupportedEncodingException, NoSuchAlgorithmException, InvalidKeyException {
        String responseBody = "<Base64EncodedPayload>";
        String signingSecret = "<Secret>";

        String requestSignature = SignatureGenerator.jsonHash(responseBody,signingSecret);
        System.out.println(requestSignature);
    }
} 

POST: https://uat.pinepg.in/api/v2/accept/payment

POST: https://pinepg.in/api/v2/accept/payment

{
  "request": "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"
}

{
  "token": "S087B99vA68R0L9gb8JI%2bqjds%2bOZaArBKLb3s7eQ%2fg7k%3d",
  "response_code": 1,
  "response_message": "SUCCESS"
}

POST: https://uat.pinepg.in/api/v2/process/payment

POST: https://pinepg.in/api/v2/process/payment

{
  "upi_data": {
    "upi_option": "UPI",
    "txn_mode": "INTENT"
  },
  "bank_account": {
    "account_number": "00000037990853412",
    "name": "HDFC",
    "ifsc": "HDFC0000053"
  }
}

{
  "pg_upi_unique_request_id": "170724PLPre22116284",
  "deep_link": "upi://pay?pa=pl.pinelabs@pineaxis&pn=Pinelabs%20Private%20Limited%20dummy&am=8.00&mam=8.00&tr=SU01J2ZMXHX4PVBVASQJPBG2XW6V&tn=Payment%20for%20342027241&cu=INR&mc=7399",
  "pine_pg_transaction_id": 342027241,
  "short_link": "https://upipay.setu.co/nO6yP65XUmwh",
  "response_code": 1,
  "response_message": "SUCCESS"
}