Ruby on rails 使用别名\u方法\u链向控制器添加功能

我正在使用alias_method_chain向控制器添加功能 但无法访问参数。此处参数[：email]为零

module Spree::MyExtensionUsersController


    def self.included(target)

        target.class_eval do
            alias_method_chain :create, :extra
        end

    end


    def create_with_extra

        #email comes from a form
        email = params[:email]

        do_something(email)
        create_without_extra
  end

end

尝试使用之前的过滤器：

如果params[：email]为零，则params是散列，因此您可以访问它。

def self.included(target)
  target.send :before_filter, :do_something_with_email, :only => :create
end

def do_something_with_email
  #email comes from a form
  email = params[:email]

  do_something(email)
end