changed response header from 200 to 401 when empty token received

The resource controller returns 200 when a request is made with an empty token e.g:

401 resource.php
200 resource.php?access_token=
401 resource.php?access_token=asd
200 resource.php?access_token=46422d7e0b0db9093526c08c47ef33da388bbb9a