Returning JSON message in PHP - php

Question

I have written a PHP script to connect to a MySQL database and extract some information. I know that the majority of the script is working as it actually inserts a MAC address into the table (which is what it should do when the value of the MAC address in the DB table is NULL).
However, the resulting message from my script is "No license found (3)".
My question is, how can it be returning this message if it's inserting a MAC address? The else statement would only be entered if if (mysqli_num_rows($result) > 0) returned false.
What I want is for the MAC address to be checked (or inserted if NULL in the DB) and to return the message "Licensed".
Apologies for the nested if/else statements.
<?php
// Array for JSON response.
$response = array();
require_once __DIR__ . '/db_connect.php';
$db = new DB_CONNECT();
// Check for GET data.
if (isset($_GET["LicenseKey"])
&& isset($_GET["SoftwareId"])
&& isset($_GET["MacAddress"])) {
$licenseKey = $_GET['LicenseKey'];
$softwareId = $_GET['SoftwareId'];
$macAddress = $_GET['MacAddress'];
// Import database connection variables.
require_once __DIR__ . '/get_license_SQL.php';
$query = SQL_GET_LICENSE;
$query = str_replace("%1", $softwareId, $query);
$query = str_replace("%2", $licenseKey, $query);
$result = mysqli_query($db->connect(), $query);
if (!empty($result)) {
// Check for empty result.
if (mysqli_num_rows($result) > 0) {
// Get the result.
$result = mysqli_fetch_array($result);
$license = array();
$license["ExpiryDate"] = $result["ExpiryDate"];
// Check if MAC address exists.
$query = SQL_GET_MAC_ADDRESS;
$query = str_replace("%1", $licenseKey, $query);
$result = mysqli_query($db->connect(), $query);
if (!empty($result)) {
$result = mysqli_fetch_array($result);
echo json_encode($result);
if ($result["MacAddress"] == $macAddress
|| $result["MacAddress"] == NULL) {
// Device MAC address matches MAC address on record.
$response["success"] = 1;
$response["license"] = array();
if ($result["MacAddress"] == NULL) {
// Insert new MAC address into the database.
$query = SQL_INSERT_MAC_ADDRESS;
$query = str_replace("%1", $macAddress, $query);
$query = str_replace("%2", $licenseKey, $query);
mysqli_query($db->connect(), $query);
}
// Add MAC address to license array.
$license["MacAddress"] = $result["MacAddress"];
$response["message"] = "Licensed";
array_push($response["license"], $license);
echo json_encode($response);
} else {
$response["success"] = 0;
$response["message"] = "License has already been used by another device";
echo json_encode($response);
}
} else {
$response["success"] = 0;
$response["message"] = "No license found (2)";
array_push($response["license"], $license);
echo json_encode($response);
}
} else {
$response["success"] = 0;
$response["message"] = "No license found (3)";
array_push($response["license"], $license);
echo json_encode($response);
}
} else {
$response["success"] = 0;
$response["message"] = "No license found (4)";
echo json_encode($response);
}
} else {
$response["success"] = 0;
$response["message"] = "Required field(s) missing";
echo json_encode($response);
}
?>
db_connect.php :
<?php
class DB_CONNECT {
function __construct() {
$this->connect();
}
function connect() {
require_once __DIR__ . '/db_config.php';
$con = mysqli_connect(DB_SERVER,DB_USER,DB_PASSWORD,DB_DATABASE);
$db = mysqli_select_db($con, DB_DATABASE) or die(mysqli_error()) or die(mysqli_error());
return $con;
}
}
?>
get_license_SQL.php :
<?php
define('SQL_GET_LICENSE', "SELECT licenses.ExpiryDate
FROM licenses
WHERE licenses.SoftwareId=%1 AND licenses.LicenseKey=%2");
define('SQL_GET_MAC_ADDRESS', "SELECT licenses.MacAddress
FROM licenses
WHERE licenses.LicenseKey=%1");
define('SQL_INSERT_MAC_ADDRESS', "UPDATE licenses
SET MacAddress=%1
WHERE licenses.LicenseKey=%2");
?>

Answer 1

Please look at the following lines of code
if ($result["MacAddress"] == NULL) {
// Insert new MAC address into the database.
$query = SQL_INSERT_MAC_ADDRESS;
$query = str_replace("%1", $macAddress, $query);
$query = str_replace("%2", $licenseKey, $query);
mysqli_query($db->connect(), $query);
}
// Add MAC address to license array.
$license["MacAddress"] = $result["MacAddress"];
You are running the following query but you are not storing the result in a variable after insertion in the database:
mysqli_query($db->connect(), $query);
In the following line the $result array has the old values from the database which were fetched prior to insertion. Please try to store the values in a variable and use that variable after the insertion.
$license["MacAddress"] = $result["MacAddress"];