Using namespaces to organize your Rails code base

Sometimes you want to group areas of your application under one roof. For example, let's say you're building a multisided marketplace or building a CMS as part of your application. Let's pretend we're doing the latter.

Without namespacing, all of your resources would live in app/models whether a part of the CMS or not. If we wanted to group the resources managed by the CMS portion of the application we could namespace them in a module.

Creating models under a namespace

The Rails generators support namespacing code using the namespace/resource pattern.

bin/rails generate model cms/article title:string body:text

This generates a Cms module at app/models/cms.rb that defines the table prefix for the namespace:

module Cms
  def self.table_name_prefix
    'cms_'
  end

The underlying table in PostgreSQL would be named cms_articles, and the model in app/models/cms/article.rb would look like the following:

module Cms
  class Article < ApplicationRecord
  end
end

Namespacing controllers and views

Let's say the resources for our CMS should be managed under the http://localhost:3000/cms path in the URI. The Rails router makes this easy.

# frozen_string_literal: true

Rails.application.routes.draw do
  namespace :cms do
    resources :articles
  end
end

and our controller would look something like this app/controllers/cms/articles.rb:

module Cms
  class ArticlesController < ApplicationController
    def index
      # code for /cms/articles here
    end
  end
end

and our corresponding views would live in app/views/cms/articles/index.html.erb

Conclusion

Namespacing our models has made a code base with several hundred models easier to navigate and reason about, and I think it is a pattern worth considering. Tomorrow we'll talk about setting up Rails to handle the acronyms in your codebase so that we can reference our CMS module as CMS instead of Cms.