Rails Dynamic Subdomain Constraint / Store Example

application.rb

and dont forget

config.eager_load_paths << Rails.root.join('lib')

application_controller.rb

class ApplicationController < ActionController::Base
  def current_organization
    @current_organization ||= ::Subdomains::Organization[request.subdomain]
  end
end

routes.rb

  Myapp::Application.routes.draw do
    namespace :api, :constraints => ::Subdomains::Organization do
      resources :posts
    end
  end

subdomains.rb

#put in lib and eager load
module Subdomains
  class Organization
    class << self
      attr_accessor :subdomains
    end

    def self.loaded_subdomains
      return unless load_subdomains?

      @loaded_subdomains ||= ::Organization.by_active.inject({}) do |hash, organization|
        hash[organization.subdomain] = organization
        hash
      end
    end

    def self.load_subdomains?
      ::ActiveRecord::Base.connection.table_exists?("organizations")
    end

    @subdomains ||= loaded_subdomains

    def self.matches?(request)
      subdomains.include?(request.subdomain)
    end

    def self.[](key)
      subdomains[key]
    end
  end
end