//Функция для работы с QIWI WEBHOOK
    private function getReqParams(){
        //Make sure that it is a POST request.
        if(strcasecmp($_SERVER['REQUEST_METHOD'], 'POST') != 0){
            throw new Exception('Request method must be POST!');
        }

        //Receive the RAW post data.
        $content = trim(file_get_contents("php://input"));

        //Attempt to decode the incoming RAW post data from JSON.
        $decoded = json_decode($content, true);

        //If json_decode failed, the JSON is invalid.
        if(!is_array($decoded)){
            throw new Exception('Received content contained invalid JSON!');
        }

        //Check if test
        if ($decoded['test'] == 'true') {
          throw new Exception('Test!');
        }

        // Строка параметров
        $reqparams = $decoded['payment']['sum']['currency'] . '|' . $decoded['payment']['sum']['amount'] . '|'. $decoded['payment']['type'] . '|' . $decoded['payment']['account'] . '|' . $decoded['payment']['txnId'];
        // Подпись из запроса
        foreach ($decoded as $name=>$value) {
           if ($name == 'hash') {
                $SIGN_REQ = $value;
           }
        }

        return [$reqparams, $SIGN_REQ];
    }

    public function qiwi_hook()
    {
        $content = json_decode(trim(file_get_contents("php://input")));
        if (!$content->hookId || $content->hookId != config_item('qiwi_hookid')) {
            die(json_encode(['error' => 1]));
        }

        //Проверяем контрольную подпись запроса
        $request = getReqParams();
        $reqres = hash_hmac("sha256", $request[0], base64_decode(config_item('qiwi_hookkey')));

        if (!hash_equals($reqres, $request[1])) {
            die(json_encode(['error' => 2]));
        }

        //Проверяем на то, что не зачисли ранее баланс пользователю
        if ($this->paymentsystems_model->get_by(['uniq_id' => $content->payment->txnId])) {
            die(json_encode(['error' => 3]));
        }

        //Проверяем на нужную валюту и статус платежа
        if ($content->payment->total->currency != 643 || $content->payment->status != 'SUCCESS' || !$content->payment->comment) {
            die(json_encode(['error' => 4]));
        }

        //Проверяем наличие пользователя в базе данных
        $user = $this->user_model->get((int)$content->payment->comment);

        if (!$user->id) die(json_encode(['error' => 5]));

        //Зачисляем баланс пользовател.
        die(json_encode(['ok' => true]));
    }