rails api versioned

app-constraints-api_constraint.rb

class ApiConstraint
  def initialize(options)
    @version = options[:version]
    @default = options[:default]
  end
 
  def matches?(request)
    @default || request.headers.fetch(:accept).include?("version=#{version}")
  end
end

config-routes.rb

Rails.application.routes.draw do
  namespace :api, defaults: {format: 'json'} do
    scope module: :v1, constraints: ApiConstraint.new(version: 1, default: true) do
      resources ..., shallow: true do
        resources ...
      end
    end
  end
end