Rest WebAPI Upload Document

Hi all,

I want to learn how to upload document on a REST webAPI.

What I want first is to fetch the document from POSTMAN to Appian ( for Test purposes only ). However, I'm getting 500 internal server just by including a document from my body. Without including a document, it works fine. 

my Body is a "Form-data",

My issue probably is on my Web API Object of Appian ( request ), can you advice on this one on fetching request data from POSTMAN? Thanks

rule!REST_Route(
request: http!request,
handlers: {
rule!REST_Route(
path: "/test",
handlers: rule!TEST_PostTestAPIHandler(request: _)
)
}
)