为什么request.referrer在Devise中对after_sign_out_for有效，但在after_sign_in中无效

Question

I have this in my application_controller.rb

  def after_sign_in_path_for(resource)
     request.referrer
  end

  def after_sign_out_path_for(resource_or_scope)
    request.referrer
  end

It works perfectly on the sign out. It sends the user back to the same page they were on.

I would like to do the reverse for the sign in, but it gives me an infinite loop on the sign in.

Why does this not work both ways?

Edit 1 : To be precise, I get a Chrome, on OS X, message that says this:

This webpage has a redirect loop

Answer 1

this would only make sense if request.referrer points to some action that tries to do another login.

you can find out about that by always having a terminal window open running tail -f log/development.log . all the information that you need should be in there. where does the request come from, where does it redirect to, why is there another redirect.

anyways, there are other ways of sending a user back to it's origin. request.referrer is an optional header and often comes with a hassle in testing. devise itself offers different ways of customizing the after_sign_in_path_for methods.

read the method documentation:

  # 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.
  #
  # By default, it first tries to find a valid resource_return_to key in the
  # session, then it fallbacks to resource_root_path, otherwise it uses the
  # root path. For a user scope, you can define the default url in
  # the following way:
  #
  #   map.user_root '/users', :controller => 'users' # creates user_root_path
  #
  #   map.namespace :user do |user|
  #     user.root :controller => 'users' # creates user_root_path
  #   end
  #
  # If the resource root path is not defined, root_path is used. However,
  # if this default is not enough, you can customize it, for example:
  #
  #   def after_sign_in_path_for(resource)
  #     stored_location_for(resource) ||
  #       if resource.is_a?(User) && resource.can_publish?
  #         publisher_url
  #       else
  #         signed_in_root_path(resource)
  #       end
  #   end
  #
  def after_sign_in_path_for(resource_or_scope)
    stored_location_for(resource_or_scope) || signed_in_root_path(resource_or_scope)
  end