How to include remote web page

I have a simple problem but can't find a simple solution. I want to include remote (dynamically created) web page into Drupal generated page. Previously i used PHP filter module in Drupal, so i would write something like readfile("remoteURL") in CKeditor and that worked fine. Now, i'm searching for something more elegant and more secure but i just can't find it. Anybody knows? Thx.

Regards.

Add a preprocess hook to your theme and parse the DOM of the external page for the HTML you want to include:

mytheme.theme

use Drupal\Component\Utility\Html;

/**
 * Implements hook_preprocess_HOOK() for node templates.
 */
function mytheme_preprocess_node(&$variables) {
  $url = 'www.example.com';
  $response = \Drupal::httpClient()->get($url);
  $dom = Html::load((string) $response->getBody());
  $xpath = new \DOMXPath($dom);
  $nodes = $xpath->query('/html/body/div');
  foreach ($nodes as $node) {
    $external_content = $dom->saveHTML($node);
    $variables['content']['external'][] = ['#markup' => $external_content];
  }
}