Expand parameter validation to type File

[dblock]

It's unclear how to require an uploaded multipart file parameter. We could also expand this to file formats.

[taybin]

I was just wondering about this today. I saw someone using Binary as a type, but I'm working with a CSV file, so that doesn't seem completely appropriate. Although having grape parse and validate filetypes seems very much out of scope, so I wouldn't expect that I could do something like type: CSV and have it do much except provide some documentation.

[dblock]

I think it could totally validate parameters with an external validator. We already do a lot of it with Virtus built-in types, could expand to more.

[dnesteryuk]

@dblock I think this one is covered. Isn't it?

[dblock]

Yup. Also if you're sure just close it @dnesteryuk, what do I know? :)