title: PHP: Checking request referrer for URL params
body: <p>I am a Ruby dev. but doing some patch work on PHP and still learning the ropes.<br>
  There is a function I have that used to check the URL params inside the Account function by calling: <code>$request-&gt;has("PARAM HERE")</code></p>
  
  <p>However, I need to check the URL params from inside a different function, storeCart, now which doesn't have direct access to access to the request params but when looking at the request info, I can see it has the url with the params inside the "referrer" part of the request.  How can I use this to accomplish checking against the param?</p>