gozap_api/Admin/Swap/free_swap.php

<?php
include_once "../../include/DB.php";

$RiderID="";
$ReturnBatteryID="";
$SwapBatteryID="";

if (isset($_POST["RiderID"]) && !empty($_POST["RiderID"])) {
    $RiderID=$_POST["RiderID"];
}
if (isset($_POST["ReturnBatteryID"]) && !empty($_POST["ReturnBatteryID"])) {
    $ReturnBatteryID=$_POST["ReturnBatteryID"];
}
if (isset($_POST["SwapBatteryID"]) && !empty($_POST["SwapBatteryID"])) {
    $SwapBatteryID=$_POST["SwapBatteryID"];
}

$SwapInsertSql = "INSERT INTO swap(RiderID, ReturnBatterID, SwappedBatterID) VALUES ('$RiderID','$ReturnBatteryID','$SwapBatteryID')";

$SwapInsertresult = $conn->query($SwapInsertSql);
if ($SwapInsertresult === TRUE) {
    $value = array(
        "RiderID"=>$RiderID,
        "ReturnBatteryID"=>$ReturnBatteryID,
        "SwapBatteryID"=>$SwapBatteryID,
        "Message"=>"Swap Data saved successfully",
      );
      // Use json_encode() function
      $json = json_encode($value);
}else {
    http_response_code(404);
    $errorMesage= $conn->error;
    // Declare an array with error message 
    $value = array(
      "Message"=>"Something went wrong",
      "Error"=>$errorMesage
    );
    // Use json_encode() function
    $json = json_encode($value);
}
// Display the output
echo ($json);
$conn->close();