Should "type" be picked up from the "using" option?

[jhollinger]

Currently you have to specify both using and type, e.g. expose :widget, using: Entities::Widget, documentation: {type: 'Widget'}. Seems redundant. Is there any reason why type shouldn't be inferred from using when it's missing? I can't think of a reason but thought I'd ask first. If there are no objections I'll submit a PR.

[dblock]

Can you give a full endpoint example? I think this is just a subset of a much bigger issue.

[jhollinger]

So if I have an endpoint like this:

class ApiV1::Entities::Category < Grape::Entity
  expose :name, documentation: {type: 'string', desc: 'Category name'}
end

class ApiV1::Entities::Widget < Grape::Entity
  expose :id, documentation: {type: 'integer', desc: 'Widget ID'}
  expose :name, documentation: {type: 'string', desc: 'Widget name'}
  # This is the important part
  expose :category, using: ApiV1::Entities::Category, documentation: {desc: 'Widget Category'}
end
...
get 'widgets/:id' do, http_codes: [[200, 'Ok', ApiV1::Entities::Widget]] do
  widget = Widget.find(params[:id])
  present widget, with: ApiV1::Entities::Widget
end

The Swagger JSON response looks like this (note that "category" has a null $ref):

,"models": {
  "ApiV1::Widget":{"id":"ApiV1::Widget","properties":{"id":{"type":"integer","description":"Widget ID"},"name":{"type":"string","description":"Widget name"},"category":{"$ref":null,"description":"Widget Category"}}},
  "ApiV1::Category":{"id":"ApiV1::Category","properties":{"name":{"type":"string","description":"Category name"}}}}

But if I instead specify a type when exposing category:

  expose :category, using: ApiV1::Entities::Category, documentation: {type: 'ApiV1:Category', desc: 'Widget Category'}

I get the expected response:

,"models":{
  "ApiV1::Widget":{"id":"ApiV1::Widget","properties":{"id":{"type":"integer","description":"Widget ID"},"name":{"type":"string","description":"Widget name"},"category":{"$ref":"ApiV1::Category","description":"Widget Category"}}},
  "ApiV1::Category":{"id":"ApiV1::Category","properties":{"name":{"type":"string","description":"Category name"}}}}

I think it would be reasonable for these two cases to behave the same way.

[dblock]

Yes, I agree.