How to route with Devise with subdomains?

Question

I'm working on a Rails apps that uses an app subdomain. For example, if a user visits my application at www.mysite.com and logs in, they should be redirected to app.mysite.com/ (which should be the articles#index page as it's the authenticated root). For some reason, when I try to log in, it signs me in ok, but redirects me to my main root route, rather than the authenticated root route. Here is my routes.rb file:

Rails.application.routes.draw do
  devise_for :users, path: '', path_names: { 
    sign_up: 'signup', 
    sign_in: 'login',
    sign_out: 'logout' 
  }

  authenticated :user do
    constraints subdomain: 'app' do
      get '/topics', to: 'topics#index'
      get '/articles', to: 'articles#index'
  
      root to: 'articles#index', as: :authenticated_root
    end
  end

  root 'home#index'
end

Do I need to adjust the devise set up so that it's aware of the app subdomain? If so, how?

Any and all help would be greatly appreciated.

Thanks!

Answer 1

By default Devise just redirects to the root path:

  def after_sign_in_path_for(resource_or_scope)
    stored_location_for(resource_or_scope) || signed_in_root_path(resource_or_scope)
  end

signed_in_root_path will look for user_root_path, root_path and then fall back to "/".

Since this is a relative path it will always redirect back to the same subdomain that the request came from.

You need to alter the redirect after sign in to use an absolute URL:

def after_sign_in_path_for(resource)
  stored_location_for(resource) || root_url(subdomain: 'app')
end

This method can either be overridden in your ApplicationController (since Devise inherits from it) or by subclassing Devise::RegistrationsController.