grape_example.rb

require 'goliath'
require 'em-synchrony'
require 'em-synchrony/em-mongo'
require 'grape'
require './app/models/mission.rb' 
require './app/models/player.rb' 

module MyAppName
  class API_v1 < Grape::API
    prefix 'api'   
    version 'v1', :using => :header, :vendor => 'company_id' do 
      
      format :json

      resource 'missions' do 

        # All mission API endpoints go here...
        # ...
        
        desc "Get a mission record using its id as key", {
        :params => {
           "id" => { :id => "Mission id.", :required => true }
          }
        }
      
      	get "/:id" do  
        	error! 'Unauthorized', 401 unless env['HTTP_SECRETK'] == 'a secret key'
        	missions_json = env.missions_coll.find({'_id' => params[:id]})
        	error! 'Mission not found', 404 unless missions_json != []
        	mission = missions_json.map {|i| Mission.from_json(i)}.first 
          # map returns an array of 1 item, so get first as the mission object
          # do something with the mission object here
          # then return object to caller as json
        	mission.first.to_json
      	end    
        
      #...       

      resource 'players' do 

        # All player API endpoints go here...
        # ...

        desc "Get a player record using its id as key", {
        :params => {
           "id" => { :id => "Player id.", :required => true }
          }
        }

      	get "/:id" do  
          error! 'Unauthorized', 401 unless env['HTTP_SECRETK'] == 'a secret key' 
          players_json = env.players_coll.find({'_id' => params[:id]})   
          error! 'Player not found', 404 unless players_json != []
          players = players_json.map {|i| Player.from_json(i)} 
          players.first.to_json 
        end    

      #...
   end
end