Refactoring multiple if statements for user authentication with subdomains

Answer 1

Can you move some of the logic to the user model, rather than having it in the controller? That way, your code will be more DRY and better encapsulated.

Answer 2

As Andrew said, you need to have this logic in your user model. I will go a step further and make each condition a method to keep the code clean, understandable, reausable and follow Single Responsibility Principle. And also define a method in the user model that returns state, like so.

class User

  def get_state(request)
    return 'state1' if no_company_and_subdomain?(request)
    return 'state2' if has_company_that_match_subdomain?(request)
    return 'state3' if admin_has_company_that_match_subdomain?(request)
  end

  def no_company_and_subdomain?(request)
    company.nil? && request.subdomains.empty?
  end

  def has_company_that_match_subdomain?(request)
    return false if company.nil? || is_admin
    company.downcase == request.subdomains.first.downcase
  end

  def admin_has_company_that_match_subdomain?(request)
    return false if company.nil? || !is_admin
    company.downcase == request.subdomains.first.downcase
  end

end

and then your controller code will become like this

if !session[:user_id].nil?
  @user = User.find(session[:user_id])
  @user.get_state
end

Obviously, you can rename the methods more sensibly based on your requirements.

Answer 3

Check out replace type with polymorphism and replace type with strategy refactoring pattern (in your case latter one seems to fit better). It might simplify your code, especially if you have multiple similar conditionals in your code.

Refactoring Ruby is a good source of informations on that topic.