IFrameUrlHelper.php

<?php

namespace Drupal\media;

use Drupal\Component\Utility\Crypt;
use Drupal\Core\PrivateKey;
use Drupal\Core\Routing\RequestContext;
use Drupal\Core\Site\Settings;

/**
 * Providers helper functions for displaying oEmbed resources in an iFrame.
 *
 * @internal
 *   This is an internal part of the oEmbed system and should only be used by
 *   oEmbed-related code in Drupal core.
 */
class IFrameUrlHelper {
    
    /**
     * The request context service.
     *
     * @var \Drupal\Core\Routing\RequestContext
     */
    protected $requestContext;
    
    /**
     * The private key service.
     *
     * @var \Drupal\Core\PrivateKey
     */
    protected $privateKey;
    
    /**
     * IFrameUrlHelper constructor.
     *
     * @param \Drupal\Core\Routing\RequestContext $request_context
     *   The request context service.
     * @param \Drupal\Core\PrivateKey $private_key
     *   The private key service.
     */
    public function __construct(RequestContext $request_context, PrivateKey $private_key) {
        $this->requestContext = $request_context;
        $this->privateKey = $private_key;
    }
    
    /**
     * Hashes an oEmbed resource URL.
     *
     * @param string $url
     *   The resource URL.
     * @param int $max_width
     *   (optional) The maximum width of the resource.
     * @param int $max_height
     *   (optional) The maximum height of the resource.
     *
     * @return string
     *   The hashed URL.
     */
    public function getHash($url, $max_width = NULL, $max_height = NULL) {
        return Crypt::hmacBase64("{$url}:{$max_width}:{$max_height}", $this->privateKey
            ->get() . Settings::getHashSalt());
    }
    
    /**
     * Checks if an oEmbed URL can be securely displayed in an frame.
     *
     * @param string $url
     *   The URL to check.
     *
     * @return bool
     *   TRUE if the URL is considered secure, otherwise FALSE.
     */
    public function isSecure($url) {
        if (!$url) {
            return FALSE;
        }
        $url_host = parse_url($url, PHP_URL_HOST);
        $system_host = parse_url($this->requestContext
            ->getCompleteBaseUrl(), PHP_URL_HOST);
        // The URL is secure if its domain is not the same as the domain of the base
        // URL of the current request.
        return $url_host && $system_host && $url_host !== $system_host;
    }

}