previousable_controller.rb

# This concern helps controllers redirect to the previous page by storing in session
# the current GET request.
#
# On controllers that need to redirect or that you don't want to keep track of, use:
#     skip_before_action :store_previous_url
#
# And then you can redirect to `session[:previous_url]` or use the
# `redirect_to_previous_or_root` helper.
#
# Also, this catches exceptions thrown by `redirect_to :back` when there is
# no referrer by redirecting to the latest GET request.
module PreviousableController
  extend ActiveSupport::Concern

  included do
    # This is not an after_action because authentication redirects usually
    # halt the callback chain.
    before_action :store_previous_url

    # Catch redirect_to :back
    rescue_from ActionController::RedirectBackError,
                with: :redirect_to_previous_or_root
  end


  protected

  def store_previous_url
    session[:previous_url] = request.fullpath if request.get?
  end

  def redirect_to_previous_or_root
    redirect_to session[:previous_url] || root_url
  end
end