Как исправить ошибку «Несуществующий класс: Razorpay» при интеграции Razorpay в codeigniter

Question

Привет, я пытаюсь интегрировать платежный шлюз razorpay в codeigniter. Код, который я использую:

CONTROLLER

<?php
class Payment_Gateway extends CI_Controller {
    public function __construct() {
        parent::__construct ();
        $this->load->library('payment_gateway/razorpay-php/Razorpay');  
    }
    public function payment(){
        $this->load->view('pay');
    }
}

?>

Я скопировал папку razorpay-php в папку system/libraries/payment_gateway

ФАЙЛ БИБЛИОТЕКИ RAZORPAY (Razorpay.php)

<?php
$CI =& get_instance();
$CI->load->library('payment_gateway/razorpay-php/libs/Requests-1.6.1/library/Requests');
Requests::register_autoloader(); 
spl_autoload_register(function ($class)
{
    // project-specific namespace prefix
    $prefix = 'Razorpay\Api';

    // base directory for the namespace prefix
    $base_dir = __DIR__ . '/src/';

    // does the class use the namespace prefix?
    $len = strlen($prefix);

    if (strncmp($prefix, $class, $len) !== 0)
    { 
        // no, move to the next registered autoloader
        return;
    }

    // get the relative class name
    $relative_class = substr($class, $len);

    $file = $base_dir . str_replace('\\', '/', $relative_class) . '.php';

    // if the file exists, require it
    if (file_exists($file))
    {
        require $file;
    }
});

КОД ПРОСМОТРА (pay.php)

<?php 
error_reporting(E_ALL);ini_set('display_error', 'on');
extract($pay_data);
session_start();
$keyId              = $keyId;
$keySecret          = $keySecret;
$displayCurrency    = $displayCurrency;

// Create the Razorpay Order

use Razorpay\Api\Api;

$api = new Api($keyId, $keySecret);

$orderData = [
    'receipt'         => 3456,
    'amount'          => $amount * 100, // 2000 rupees in paise
    'currency'        => 'INR',
    'payment_capture' => 1 // auto capture
];

$razorpayOrder = $api->order->create($orderData);
$razorpayOrderId = $razorpayOrder['id'];
$_SESSION['razorpay_order_id'] = $razorpayOrderId;
$displayAmount = $amount = $orderData['amount'];

if ($displayCurrency !== 'INR')
{
    $url = "https://api.fixer.io/latest?symbols=$displayCurrency&base=INR";
    $exchange = json_decode(file_get_contents($url), true);

    $displayAmount = $exchange['rates'][$displayCurrency] * $amount / 100;
}

$checkout = 'automatic';

if (isset($_GET['checkout']) and in_array($_GET['checkout'], ['automatic', 'manual'], true))
{
    $checkout = $_GET['checkout'];
}

$data = [
    "key"               => $keyId,
    "amount"            => $amount,
    "name"              => "DJ Tiesto",
    "description"       => "Tron Legacy",
    "image"             => "https://s29.postimg.org/r6dj1g85z/daft_punk.jpg",
    "prefill"           => [
    "name"              => "Daft Punk",
    "email"             => "customer@merchant.com",
    "contact"           => "9999999999",
    ],
    "notes"             => [
    "address"           => "Hello World",
    "merchant_order_id" => "12312321",
    ],
    "theme"             => [
    "color"             => "#F37254"
    ],
    "order_id"          => $razorpayOrderId,
];

if ($displayCurrency !== 'INR')
{
    $data['display_currency']  = $displayCurrency;
    $data['display_amount']    = $displayAmount;
}

$json = json_encode($data);

?>

<form action="<?php echo base_url(); ?>index.php/payment_gateway/verify" method="POST">
  <script
    src="https://checkout.razorpay.com/v1/checkout.js"
    data-key="<?php echo $data['key']?>"
    data-amount="<?php echo $data['amount']?>"
    data-currency="INR"
    data-name="<?php echo $data['name']?>"
    data-image="<?php echo $data['image']?>"
    data-description="<?php echo $data['description']?>"
    data-prefill.name="<?php echo $data['prefill']['name']?>"
    data-prefill.email="<?php echo $data['prefill']['email']?>"
    data-prefill.contact="<?php echo $data['prefill']['contact']?>"
    data-notes.shopping_order_id="3456"
    data-order_id="<?php echo $data['order_id']?>"
    <?php if ($displayCurrency !== 'INR') { ?> data-display_amount="<?php echo $data['display_amount']?>" <?php } ?>
    <?php if ($displayCurrency !== 'INR') { ?> data-display_currency="<?php echo $data['display_currency']?>" <?php } ?>
  >
  </script>
  <!-- Any extra fields to be submitted with the form but not sent to Razorpay -->
  <input type="hidden" name="shopping_order_id" value="3456">
</form>

Во время работы я получаю сообщение об ошибке типа "Non-existent class: Razorpay". Значение $class в Razorpay.php выглядит как "CI_Razorpay".

Я не пользуюсь композитором, поэтому буду признателен, если кто-нибудь подскажет, как интегрировать этот платеж без композитора.