How to do token authentication URLs with BunnyCDN

How to generate URL authentication tokens and expiry with PHP on BunnyCDN (Bunny Net) URLs.

This means that URL’s fetched that do not have a valid token and expiry will return a 403 HTTP response.

Using token authentication on URLs makes traffic need to go through your website rather than directly accessing the media.

Here is a PHP function created with details from the Bunny net blog post.

function URLTokenGenerate(string $path, string $zone_url, int $expires_seconds = 3600): string
{
    $security_key = 'URL-TOKEN-AUTH-KEY-HERE';
    $expires = (time() + $expires_seconds);
    $hash_base = $security_key . $path . $expires;
    $token = md5($hash_base, true);
    $token = base64_encode($token);
    $token = strtr($token, '+/', '-_');
    $token = str_replace('=', '', $token);
    return "{$zone_url}{$path}?token={$token}&expires={$expires}";
}

Put in your token authentication key at $security_key

An example call:

$url = URLTokenGenerate('/images/banner.jpg', 'https://myweb.b-cdn.net', 300);

Will return similar to

https://myweb.b-cdn.net/images/banner.jpg?token=_AWA1k7ukqLqx2EyXUhrHA&expires=1627651686

This URL will be valid until 5 minutes (300 seconds) after creation.