added responseModel support

[bagilevi]

Include the entity defined in http_codes as a responseModel.

Example:

desc 'This returns something or an error', {
  entity: Entities::Something,
  http_codes: [
    [200, "OK", Entities::Something],
    [403, "Refused to return something", Entities::Error]
  ]
}

[dblock]

Merged via tim-vandecasteele@99b1430, thank you. Please check my commit, there were a few changes.

[dspaeth-faber]

@bagilevi how can I use this error model in grape?

error!(???, 400)

[dspaeth-faber]

Oh, i did find it. You don't use error!. Maybe it would be great when error! uses the error hash converts it into a openstuct and present it via the presenter.

[bagilevi]

@dspaeth-faber I define a custom error_formatter which will find an error presenter class based on the error code.

error_formatter :json, ->(message, backtrace, options, env) {
  h = if message.is_a?(String)
        { message: message }
      else
        message
      end
  klass = Iron::Entities::Error
  if h[:code] && (klass_name = h[:code].try(:to_s).try(:classify)) && klass.const_defined?(klass_name)
    klass = klass.const_get(klass_name)
  end
  errobj = klass.represent(Hashie::Mash.new(h))
  JSON.generate(error: errobj)
}

error!({ code: 'deleted', message: "Account has been deleted, please delete your references." }, 410)

[dspaeth-faber]

@bagilevi Thanks! Look's like some thing which should be added to grape-enitity.

[dspaeth-faber]

I did use your example and came up with the following, maybe it is usefull for you too

module API
  module ErrorFormatter
    module_function
    def call(message, backtrace, options = {}, env = nil)
      if message.is_a?(Hash)
        message =  message.dup
        presenter = message.delete(:with)

        if presenter
          message = Hashie::Mash.new(message)
          message = presenter.represent(message, {env: env}).serializable_hash
        end
      end

      Grape::ErrorFormatter::Json.call(message, backtrace, options, env)
    end
  end
end

error!({ code: 'deleted', with: Iron::Entities::Error, message: "Account has been deleted, please delete your references." }, 410)