Returning Payments Callback

<?php

    $post = $_POST;

    $merchant_key   = 'YYYYYYYYYYYYYY';
    $merchant_salt  = 'ZZZZZZZZZZZZZZ';

    $hash = base64_encode( hash_hmac('sha256', $post['merchant_id'].$post['trans_id'].$merchant_salt, $merchant_key, true) );

    if( $hash != $post['hash'] )
        die('PAYTR notification failed: bad hash');

    $processed_result = json_decode($post['processed_result'],1);
    foreach($processed_result as $trans)
    {

    }

    echo "OK";
    exit;
?>

# Python 3.6+

import base64
import hashlib
import hmac
import json

from django.shortcuts import render, HttpResponse
from django.views.decorators.csrf import csrf_exempt

@csrf_exempt
def callback(request):
    if request.method != 'POST':
        return HttpResponse(str(''))

    post = request.POST

    merchant_key = b'YYYYYYYYYYYYYY'
    merchant_salt = 'ZZZZZZZZZZZZZZ'

    hash_str = post['merchant_id'] + post['trans_id'] + merchant_salt
    hash = base64.b64encode(hmac.new(merchant_key, hash_str.encode(), hashlib.sha256).digest())

    if hash != post['hash']:
        return HttpResponse(str('PAYTR notification failed: bad hash'))

    processed_result = json.loads(post['processed_result'])

    for trans in processed_result:

        print(trans)

    return HttpResponse(str('OK'))

using System;
using System.Collections.Generic;
using System.Linq;
using System.Security.Cryptography;
using System.Text;
using System.Web;
using System.Net.Mail;
using System.Web.UI;
using System.Web.UI.WebControls;
using Newtonsoft;
using Newtonsoft.Json;
using Newtonsoft.Json.Linq;
using System.IO;

public partial class paytr_geri_donen_odemeler_callback_ornek : System.Web.UI.Page {

    string merchant_key = "AAAAAA";
    string merchant_salt = "XXXXXXXXXXXXXXXX";

    protected void Page_Load(object sender, EventArgs e)
    {

        string trans_id = Request.Form["trans_id"];
        string merchant_id = Request.Form["merchant_id"];
        string hash = Request.Form["hash"];
        string processed_result = Request.Form["processed_result"];

        string Birlestir = string.Concat(merchant_id, trans_id, merchant_salt);
        HMACSHA256 hmac = new HMACSHA256(Encoding.UTF8.GetBytes(merchant_key));
        byte[] b = hmac.ComputeHash(Encoding.UTF8.GetBytes(Birlestir));
        string token = Convert.ToBase64String(b);

        if (hash.ToString() != token)
        {

            Response.Write("PAYTR notification failed: bad hash");
            return;
        }

        dynamic dynJson = JsonConvert.DeserializeObject(processed_result);

        foreach (var item in dynJson)
        {

        }

        Response.Write("OK");
    }

}

  var request = require('request');
var crypto = require('crypto');
var express = require('express');
var app = express();

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

var merchant_id = 'XXXXXX';
var merchant_key = 'XXXXXXXXYYYYYYYY';
var merchant_salt = 'XXXXXXXXYYYYYYYY';

app.get("/list", function (req, res) {

    var start_date = '2020-11-01 00:00:00';
    var end_date = '2020-11-29 23:59:59';

    var paytr_token = crypto.createHmac('sha256', merchant_key).update(merchant_id + start_date + end_date + merchant_salt).digest('base64');

    var options = {
        'method': 'POST',
        'url': 'https://www.paytr.com/odeme/geri-donen-transfer',
        'headers': {
            'Content-Type': 'application/x-www-form-urlencoded'
        },
        form: {
            'merchant_id': merchant_id,
            'start_date': start_date,
            'end_date': end_date,
            'paytr_token': paytr_token,
        }
    };

    request(options, function (error, response, body) {
        if (error) throw new Error(error);
        var res_data = JSON.parse(body);

        if (res_data.status == 'success') {

            res.send(res_data);

        } else {

            console.log(response.body);
            res.end(response.body);
        }

    });

});

app.get("/send", function (req, res) {

    var trans_id = '';
    var trans_info = [{
        'amount': '1283',
        'receiver': 'XYZ LTD ŞTİ',
        'iban': 'TRXXXXXXXXXXXXXXXXXXXXX'
    }];

    var paytr_token = crypto.createHmac('sha256', merchant_key).update(merchant_id + trans_id + merchant_salt).digest('base64');

    var options = {
        'method': 'POST',
        'url': 'https://www.paytr.com/odeme/hesaptan-gonder',
        'headers': {
            'Content-Type': 'application/x-www-form-urlencoded'
        },
        form: {

            'trans_info': JSON.stringify(trans_info),
            'trans_id': trans_id,
            'paytr_token': paytr_token,
            'merchant_id': merchant_id,

        }
    };

    request(options, function (error, response, body) {
        if (error) throw new Error(error);
        var res_data = JSON.parse(body);

        if (res_data.status == 'success') {
            res.send(response.body);
        } else {
            res.end(response.body);
        }

    });

});

app.post("/callback", function (req, res) {
    var callback = req.body;

    var paytr_token = crypto.createHmac('sha256', merchant_key).update(callback.merchant_id + callback.trans_id + merchant_salt).digest('base64');

    if (paytr_token != callback.hash) {
        throw new Error("PAYTR notification failed: bad hash");
    }

    var processed_result = JSON.parse(callback.processed_result);

    for (const [key, value] of Object.entries(processed_result)) {
        console.log(`${key}: ${value}`);
    }

    res.send("OK");
});

var port = 3200;
app.listen(port, function () {
    console.log("Server is running. Port:" + port);
});