PHP/Laravel-based controller to add the referrer as campaign name to the download link pointing to the App Store

RefererController.php

<?php

namespace App\Controller;

use Symfony\Bundle\FrameworkBundle\Controller\AbstractController;
use Symfony\Component\HttpFoundation\Request;
use Symfony\Component\HttpFoundation\Cookie;

class Referer extends AbstractController
{
    protected function renderWithReferer($request, $template, $variables = [], $replaceDownloadURL = false)
    {

        // Use utm_source query parameter as referer if set.
        $referer = $request->query->get('utm_source');

        // If referer is not set, use ref query parameter as referer if set.
        if (!$referer) {
            $referer = $request->query->get('ref');
        }

        // If referer is not set, try using referer header as referer.
        if (!$referer) {
            $refererHeader = $request->headers->get('referer');
            if ($refererHeader) {
                $refererHost = parse_url($refererHeader, PHP_URL_HOST);

                // Avoid using server as referer.
                if (!in_array($refererHost, array('127.0.0.1', 'dailytimetracking.com', 'www.dailytimetracking.com', 'dailytimeapp.com', 'www.dailytimeapp.com'))) {
                    $referer = $refererHost;
                }
            }
        }

        // If referer is not set, try obtaining it from cookies
        if (!$referer) {
            $referer = $request->cookies->get('referer');
        }

        // Update download link if referer is available.
        $refererCookie = null;
        if ($referer) {

            // Update download link.
            $downloadUrl = $this->get('twig')->getGlobals()['download_url'];
            $downloadUrl .= '&pt=2169443&ct=' . rawurlencode($referer);
            $this->get('twig')->addGlobal('download_url', $downloadUrl);

            // Remember referer for future usage.
            $refererCookie = new Cookie('referer', $referer, strtotime('now + 60 minutes'));
        }

        // Render template.
        $response = $this->render($template, $variables);

        // Replace {{ download_url }} with actual download URL if requested
        if ($replaceDownloadURL) {
            $updatedContent = str_replace('{{ download_url }}', $this->get('twig')->getGlobals()['download_url'], $response->getContent());
            $response->setContent($updatedContent);
        }

        // Set cookie if available.
        if ($refererCookie) {
            $response->headers->setCookie($refererCookie);
        }

        return $response;
    }
}