devise-auth-resource.rb

# config/initializers/devise.rb

Devise.setup do |config|
  # ... normal setup options
  Warden::Manager.before_failure do |env,opts|
    request = Rack::Request.new(env)
    request.session[:return_to] = request.env['REQUEST_METHOD']=="GET" ? request.env['action_dispatch.request.path_parameters'] : request.env['HTTP_REFERER']
    request.session[:return_params] = request.env['action_dispatch.request.request_parameters']
  end


# app/controllers/application_controller.br
def after_sign_in_path_for(resource)
  if request.session[:return_to].is_a? String
    [request.session[:return_to], request.session[:return_params].to_query].join("?")
  elsif request.session[:return_to].is_a? Hash
    request.session[:return_to].merge!(request.session[:return_params])
  else
    super
  end
end