Json render

[nicolas-besnard]

Follow of #87 :

I think I'm done. I face a problem where the view is not found :

ActionView::MissingTemplate (Missing template devise_token_auth/registrations/create_errors with {:locale=>[:en], :formats=>[:html], :variants=>[], :handlers=>[:erb, :builder, :raw, :ruby, :jbuilder, :rabl]}.

We can see that the formats of the request if :html. I have to force my route to display JSON :

constraints format: 'json' do
   mount_devise_token_auth_for 'User', at: '/users/auth'
end

[john-griffin]

This will introduce some unnecessary dependancies.

Most people stopped using custom JSON parsers (like OJ) in Ruby last year when their performance benefits were found to be negligible. Well maintained projects use stdlib json. I have encountered memory leaks on OJ on large projects in the past and steer clear of it. It's not cool to force users of this gem to use OJ.

The use of rabl and hashie here is unnecessary. Most of the rabl files are identical and very short. Rabl is useful for large schemas and when you need to map to different formats. Why use rabl or hashie when a simple hash will suffice? Rabl also has a hard dependancy on OJ.

[nicolas-besnard]

@john-griffin : A simple hash was initially used, but you can't customize it for your project. If you have any solution for that, I'll be happy to take it :)

I'll make some search on OJ to confirm what you say. But well, I made some research last year, and the results was 2-4x faster than the default JSON Parser.

Most of the rabl files are identical and very short

They are mostly the same, but you have to provide a different file for each couple Controller - Action to be able to customize your request.

[lynndylanhurley]

@john-griffin - thank you for that link!

There is maybe another way to allow for customization of the JSON responses.

Right now most of the controller methods look like this:

# devise_token_auth/app/controllers/devise_token_auth/registrations_controller.rb
module DeviseTokenAuth
  class RegistrationsController < DeviseTokenAuth::ApplicationController

    # ...

    def update
      if @resource

        if @resource.update_attributes(account_update_params)
          render json: {
            status: 'success',
            data:   @resource.as_json
          }
        else
          render json: {
            status: 'error',
            errors: @resource.errors
          }, status: 403
        end
      else
        render json: {
          status: 'error',
          errors: ["User not found."]
        }, status: 404
      end
    end
  # ...
  end
end

We could introduce a json rendering method that can be used everywhere, so that in order to customize the responses, only one method would need to be overridden. For example:

# devise_token_auth/app/controllers/devise_token_auth/application_controller.rb

module DeviseTokenAuth
  class ApplicationController < DeviseController
    include DeviseTokenAuth::Concerns::SetUserByToken
    respond_to :json
    # ...

    def render_json_response(data, status, errors)
      response            = {}
      response[:data]     = data if data
      response[:errors]   = errors if errors
      status            ||= 200

      return render json: response, status: status
    end
  end
end

This would DRY up all of the controller methods. For example, the update method above would then look like this:

# devise_token_auth/app/controllers/devise_token_auth/registrations_controller.rb

module DeviseTokenAuth
  class RegistrationsController < DeviseTokenAuth::ApplicationController

    # ...

    def update
      if @resource        
        if @resource.update_attributes(account_update_params)
          render_json_response(@resource.as_json, 200, null)
        else
          render_json_response(null, 403, @resource.errors)
        end
      else
        render_json_response(null, 404, ["User not found"])
      end
    end

    # ...
  end
end

What do you guys think?

[nicolas-besnard]

That could be a solution, but what if I don't wan't a data or errors keys ?

[lynndylanhurley]

Then you can override just this one method. We can add an initializer option that allows for custom JSON rendering methods. Something like this:

DeviseTokenAuth.setup do |config|
  # ...

  config.json_response_format_method = MyApp::ApplicationController.render_json_response

  # ...
end

And then in app/controllers/application_controller.rb you could have this:

  class ApplicationController < ActionController::Base

    # ...

    def render_json_response(data, status, errors)
      response                     = {}
      response[:alt_data_param]    = data if data
      response[:alt_error_param]   = errors if errors
      status                     ||= 200

      return render json: response, status: status
    end

    # ...

  end

So you can organize the response however you want. And if you want rabl and oj, all you will need to do is add a single method.

[john-griffin]

@lynndylanhurley I like that approach, very flexible.

[nicolas-besnard]

Looks like a good solution :) And I like this approach too. Very simple, without dependencies. I'll close this PR and make a new one

[lynndylanhurley]

@nicolas-besnard - thanks!!! I'll be sure to add you to the contributors list for this 😃