File input

Hi, I'm trying to build a form in the uiBuilder containing a file upload input. It seems there is no such block in the builder so I tried to add an HTML block and put the input type="file" in there. When I pass the form submit action to a PHP function and print the $data the input seems to contain an empty object.

Long story short; I would like to request a file upload input block.

In the meantime, is it possible to do a form in the uiBuilder with a file upload input and how would I go about doing this? Maybe you can point me in the right direction for extending uipress, actions, filters, anything?

Regards,

Bas