Endpoints expecting multipart/related?

[NobodysNightmare]

Hi,

from reading the docs I could find out that grape basically seems to support multiple multipart content types, including multipart/related.

However, the relevant section of the documentation just reads:

Multipart POSTs and PUTs are supported as well.

The request:

curl --form image_file='@image.jpg;type=image/jpg' http://localhost:9292/upload

The Grape endpoint:

post "upload" do
  # file in params[:image_file]
end

I see how that is working for multipart/form-data and it works beautiful for that Content-Type.
However, at the moment I am not sure if that is the right thing to do for an API that is free of classical HTML forms. That is why I thought about using multipart/related instead, expecting a first part with some metadata and a second part with the actual contents of the file (which is btw. the same thing Google Drive does).

However, it is not yet clear to me how that would be possible using grape. When receiving such a request:

• the params do not contain anything except an id and route_info
• env['api.request.body'] is nil
• env['api.request.input'] is nil

Thus I don't see which options I would have to implement such an endpoint using Grape.

Is this a known/intended limitation?
Am I doing it wrong?

Any help is apprechiated.

Best regards and thanks for taking the time to review this issue! 🐈

[dblock]

I think it's not natively supported by Rack, so you might need rack-multipart_related, try adding it ahead of Grape (config.ru)? I would appreciate it if you could please add a demo with tests to https://github.com/dblock/grape-on-rack.

[NobodysNightmare]

I'll see if I can get it running using rack-multipart_related in my spare time.
For now I have chosen the path of least resistance and use multipart/form-data in the API. I fear that clients will face similar difficulties with their libraries when I would force them to not use multipart/form-data.