How to setup Concrete CMS behind CDN (Amazon CloudFront)

This is a community-contributed tutorial. This tutorial is over a year old and may not apply to your version of Concrete CMS.
Jul 16, 2016
By hissy for Developers


The main issue of using Concrete CMS behind CDN is host names.

    • CDN (Amazon CloudFront)
    • When guest users access to your site, visit to this host.
    • Origin Web server (concrete5)
    • When you login to concrete5, access to this host. |

When this case, concrete5's canonical URL is, but actual host name for gust users is .

The sub issue is cache life time.

CDN stores cache only when the full page cache is enabled, because of Cache-Control header. However, full page cache should be disabled when editing content with concrete because of host name.

How can we solve the issues?

  1. When editing content on, turn off caching.
  2. When viewing content on, turn on caching and set to canonical URL.


1. Change environment to cdn when HTTP User Agent is 'Amazon CloudFront'.


use Concrete\Core\Application\Application;

 * -----------------------------------------------------------------
 * Instantiate concrete5
 * -----------------------------------------------------------------
$app = new Application();

 * -----------------------------------------------------------------
 * Detect the environment based on the use agent
 * -----------------------------------------------------------------
    $request = \Concrete\Core\Http\Request::getInstance();
    if ($request->server->get('HTTP_USER_AGENT') == 'Amazon CloudFront') {
        return 'cdn';

return $app;

2. Turn off caching on default environment



return array(
    'cache' => array(
        'blocks' => false, // turn off block cache
        'pages' => 0, // turn off page cache

3. Turn on caching on cdn environment, and set canonical URLs



return array(
    'cache' => array(
        'blocks' => true, // turn on block cache
        'pages' => 'blocks', // cache page if all blocks support it.
    'seo' => array(
        'canonical_url' => '',
        'canonical_ssl_url' => '',
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