new feature in Rails4: Strong parameters (Rails4的新特性)

今天开始了一个RAILS4的项目。 扑面而来的一个特性： strong parameter( today I started my first Rails 4 project and met the "strong parameter" feater) 

传统的rails 3 项目，需要在model中控制 可以访问的属性（in Rails 3, the attribute white list is controlled in model) ：

# in models
class Plan < ActiveRecord::Base
    attr_accessible :name, :schedule
end

在Rails 4中，需要在controller中进行控制： ( but in Rails4, it's controlled in controller ) 

# in controller:
class PlansController < ApplicationController
  before_action :set_plan, only: [:update]
  def update
    if @plan.update plan_params
      redirect_to @plan, notice: 'Plan was successfully updated.'
    else
      render action: 'edit'
    end
  end
  private
    def set_plan
      @plan = Plan.find(params[:id])
    end 
    # this is the key! 
    def plan_params
      params.require(:plan).permit :name, :schedule
    end