trustieforge/app/api/mobile/apis/auth.rb

module Mobile

  module Entities 
    class Auth < Grape::Entity
      expose :token
      expose :user, using: User
    end
  end

  module Apis
    class Auth < Grape::API
      resource :auth do
        desc "Creates and returns access_token if valid login"
        params do
          requires :login, type: String, desc: 'Username or email'
          requires :password, type: String, desc: 'Password'
        end
        post :login do 
          user,last_logon = ::User.try_to_login(params[:login], params[:password])
          if user
            ::ApiKey.delete_all(user_id: user.id)
            key = ::ApiKey.create!(user_id: user.id)
            api_user = UserService.new.show_user(user.id)
            present :data, {token: key, user: api_user}, using: Mobile:Entities::Auth
            present :status, 0
          else
            {status: 1, message: 'Unauthorized.'}
          end
        end
      end
    end
  end
end