Use Expires header to guess if a site is built in Drupal

[emmajane]

Sites built with Drupal, and using the standard configuration, will always use a specific date for the header expires. This date is set to the birthday of the founder of the project, Dries Buytaert.

expires: Sun, 19 Nov 1978 05:00:00 GMT

This header is not always set so it is not a perfect indication of whether or not a site is built in Drupal. However, if it is set one can assume with almost 100% certainty that the site is a Drupal site.

This check could be added to: https://github.com/urbanadventurer/WhatWeb/blob/master/plugins/drupal.rb

References:

• https://en.wikipedia.org/wiki/Dries_Buytaert
• https://www.drupal.org/forum/support/post-installation/2013-04-12/expires-header-set-to-1978