问Rails + Devise:如何覆盖before_filter "authenticate_user!“的重定向

EN

before_filter :set_return_path 

def after_sign_in_path_for(resource) 
  session["user_return_to"] || root_url 
end

def set_return_path
  unless devise_controller? || request.xhr? || !request.get?
    session["user_return_to"] = request.url
  end
end

# The default url to be used after signing in. This is used by all Devise
# controllers and you can overwrite it in your ApplicationController to
# provide a custom hook for a custom resource.
# def after_sign_in_path_for(resource_or_scope)

# Only remembers the page immediately before we 
# redirect them for auth, instead of every page view

def authenticate_user!
  session["user_return_to"] = request.fullpath
  super
end

# Deletes the return path as soon as it's used, so 
# they aren't accidentally redirected back again
# next time they login

def after_sign_in_path_for(resource)
  session.delete("user_return_to") || root_path
end