Rails Grape API 'id is invalid' in request that requires no id

Question

I have a Grape API protected by Doorkeeper and I have a bunch of methods which work perfectly. However, there's one method that behaves weirdly. It is a GET request that requires no parameters and running it throws the following error:

Grape::Exceptions::ValidationErrors at /v1/discount_cards/all.json

id is invalid

My method looks like this:

desc 'Get all the cards of current customer'
params {}
get 'all' do
  current_customer.discount_cards.to_json(include:
  {
    barcode: {
      include: :barcode_type
    }
  })
end

The logs say that the error happens at line 17 of the logger.rb file, which looks like this:

module API
  class Logger
    def initialize(app)
      @app = app
    end

    def call(env)
      payload = {
        remote_addr: env['REMOTE_ADDR'],
        request_method: env['REQUEST_METHOD'],
        request_path: env['PATH_INFO'],
        request_query: env['QUERY_STRING'],
        x_organization: env['HTTP_X_ORGANIZATION']
      }

      ActiveSupport::Notifications.instrument 'grape.request', payload do
        @app.call(env).tap do |response| # <-- logs say the error is here
          payload[:params] = env['api.endpoint'].params.to_hash
          payload[:params].delete('route_info')
          payload[:params].delete('format')
          payload[:response_status] = response[0]
        end
      end
    end
  end
end

My main base.rb class looks like this:

module API
  class Dispatch < Grape::API
    mount API::V1::Base
  end

  Base = Rack::Builder.new do
    use API::Logger
    run API::Dispatch
  end
end

---

I really cannot understand what id it is talking about, and, moreover, all the other api methods work absolutely fine (post, get, put, delete).

Could you help me with resolving that issue?

Answer 1

I had this issue recently too, and it turned out to be an issue of code order for me. I found the answer here.

Grape evaluates routes in order, so with two routes, /:id and /nearby_missions, it matches /:id first, making id=nearby_missions. Then it tries to coerce nearby_missions into an Integer which fails, and you get the missing id error.

You could "fix" this by adding requirements: /\d*/ to the first route (didn't test), but you're probably just better off ordering them in the order you want them to be evaluated, which is what you did.

There's not enough info in your question for me to be sure that this is also your problem, but it could well be!