Laravel 5 / Lumen Request Header?

Question

So I am not really sure how to go about this I have tried a few things and I will list one below however what I am trying to do is store information sent in a http request in a

Answer 1

Using

echo app('request')->header('pubapi');

Instead of

echo Request::header('pubapi');

Seemed to work perfect. Could someone provide additional explanation to why this worked and my original method didn't?