Minishlink\WebPush\WebPush::prepareAndSend PHP Метод

    private function prepareAndSend(array $notifications)
    {
        $responses = array();
        /** @var Notification $notification */
        foreach ($notifications as $notification) {
            $endpoint = $notification->getEndpoint();
            $payload = $notification->getPayload();
            $userPublicKey = $notification->getUserPublicKey();
            $userAuthToken = $notification->getUserAuthToken();
            $options = $notification->getOptions($this->getDefaultOptions());
            $auth = $notification->getAuth($this->auth);
            if (isset($payload) && isset($userPublicKey) && isset($userAuthToken)) {
                $encrypted = Encryption::encrypt($payload, $userPublicKey, $userAuthToken, $this->nativePayloadEncryptionSupport);
                $headers = array('Content-Length' => Utils::safeStrlen($encrypted['cipherText']), 'Content-Type' => 'application/octet-stream', 'Content-Encoding' => 'aesgcm', 'Encryption' => 'salt=' . $encrypted['salt'], 'Crypto-Key' => 'dh=' . $encrypted['localPublicKey']);
                $content = $encrypted['cipherText'];
            } else {
                $headers = array('Content-Length' => 0);
                $content = '';
            }
            $headers['TTL'] = $options['TTL'];
            if (isset($options['urgency'])) {
                $headers['Urgency'] = $options['urgency'];
            }
            if (isset($options['topic'])) {
                $headers['Topic'] = $options['topic'];
            }
            // if GCM
            if (substr($endpoint, 0, strlen(self::GCM_URL)) === self::GCM_URL) {
                if (array_key_exists('GCM', $auth)) {
                    $headers['Authorization'] = 'key=' . $auth['GCM'];
                } else {
                    throw new \ErrorException('No GCM API Key specified.');
                }
            } elseif (array_key_exists('VAPID', $auth)) {
                $vapid = $auth['VAPID'];
                $audience = parse_url($endpoint, PHP_URL_SCHEME) . '://' . parse_url($endpoint, PHP_URL_HOST);
                if (!parse_url($audience)) {
                    throw new \ErrorException('Audience "' . $audience . '"" could not be generated.');
                }
                $vapidHeaders = VAPID::getVapidHeaders($audience, $vapid['subject'], $vapid['publicKey'], $vapid['privateKey']);
                $headers['Authorization'] = $vapidHeaders['Authorization'];
                if (array_key_exists('Crypto-Key', $headers)) {
                    // FUTURE replace ';' with ','
                    $headers['Crypto-Key'] .= ';' . $vapidHeaders['Crypto-Key'];
                } else {
                    $headers['Crypto-Key'] = $vapidHeaders['Crypto-Key'];
                }
            }
            $responses[] = $this->sendRequest($endpoint, $headers, $content);
        }
        return $responses;
    }