Anton Davydov

Building your rails API with roda

20 May 2016

Introduction

Sometimes you need to build API serveice in your rails application. Of course you can use popular solutions as grape or rails-api gems. And also you can find real examples in gitlab or rubygems projects.

But today I’m going to tell you about other framework. It’s roda. Roda was created by Jeremy Evans and it’s fast and simple ruby routing framework. So why should you take a look on it?

There’s a list of advantages of this framework:

  1. Fast;
  2. Simple;
  3. Roda provides simple way to working with big count of different plugins;
  4. You can use any architecture with it;

So I mentioned that roda is fast. If you want to verify this, just check this benchmark repository and you’ll see that roda is really fast. For example, I run benchmarks on locally and get this result:

Framework            Requests/sec  % from best
----------------------------------------------
mustermann                9389.60       100.0%
roda                      9252.03       98.53%
rack                      9246.16       98.47%
hanami-router             6240.81       66.47%
sinatra                   2935.63       31.26%
grape                     2512.17       26.75%

Integration

Roda based on rack. That’s why this integration with rails will be very simple. Firstly you need to add roda gem to your gemfile:

gem 'roda'

Secondly you need to create simple roda application. Note that you need to use json and all_verbs plugins. The first one needs to JSON responce and the second one provides all REST methods for your application (like put, patch, etc). I puted my roda application in to lib/api/base.rb path but you can use whatever you waht.

# lib/api/base.rb
require 'roda'
require 'json'

module API
  class Base < Roda
    plugin :json
    plugin :all_verbs

    route do |r|
      r.on "v1" do
        r.get 'hello' do
          { hello: :world }
        end
      end
    end
  end
end

After that you need to mount your application in config/routes.rb. This is done as well as any other rack application:

# config/routes.rb
require './lib/api/base'
mount API::Base => '/api'

And the last part, we need to split our application to different modules with different logic and routes. For this we have to create required module. In an example I created Users module with all REST routes:

# lib/api/users.rb
module API
  class Users < Roda
    plugin :json
    plugin :all_verbs

    route do |r|
      r.is 'users' do
        r.get do
          { users: User.last(10) }
        end

        r.post do
          { user: User.new }
        end
      end

      r.is 'users/:id' do |id|
        user = User.find(id)

        r.get do
          { user: user}
        end

        r.patch do
          { user: 'updated' }
        end

        r.delete do
          { user: 'deleted' }
        end
      end
    end
  end
end

Finnaly you need to mount our module to roda application. It is very simple too.

# lib/api/base.rb
require 'roda'
require 'json'
require 'users'

module API
  class Base < Roda
    plugin :json
    plugin :all_verbs

    route do |r|
      r.on "v1" do
        r.run API::Users
      end
    end
  end
end

That’s all. Now we have a simple roda API application which integrated to our rails app.

Problems / future

In the last part I want to list problems and ideas what I want to solve in future.

  1. Roda doesn’t have a swagger integrating from the box. Now I’m thinking about using swagger-block gem for it.
  2. Also roda doesn’t typecast your params. I know that grape uses virtus gem for this. And this feature you should realize by youself too.

Conclusion

On this blog post I wanted to show you that you’re not limited only to popular API server gems. As you can see roda have amazing ideas and properties such as modulatiry, simplicity, speed and stability. Also this framework has a simple way to integration in to your rails application.

Happy hacking! emoji

Further reading

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