"super"和"super do | u |"之间的区别 使用Devise的上下文

Question

好的,所以我觉得我得到了超级does独立的东西.基本上在Devise中,if Users::RegistrationsController < Devise::RegistrationsController,然后在任何动作上,有一个super遗嘱首先在父亲中Devise::RegistrationsController调用同一个命名动作的逻辑,然后再调用你所写的内容.

换一种说法...

class Devise::RegistrationsController
  def new
    puts "this is in the parent controller"
  end
end

class Users::RegistrationsController < Devise::RegistrationsController
  def new
    super
    puts "this is in the child controller"
  end
end

# Output if users#new is run would be:
# => "this is in the parent controller"
# => "this is in the child controller"

# If super were reversed, and the code looked like this
# class Users::RegistrationsController < Devise::RegistrationsController
  #  def new
    #  puts "this is in the child controller"
    #  super
  #  end
#  end
# Then output if users#new is run would be:
# => "this is in the child controller"
# => "this is in the parent controller"

我很好奇的是,我看到有些人这样做:

class Users::RegistrationsController < Devise::RegistrationsController
  def new
    super do |user|
      puts "something"
    end
  end
end

我很难绕过do block正在完成的事情.在我的例子中,在创建资源(用户)之后,我想在该资源(用户)上调用另一个方法.

当前代码:

class Users::RegistrationsController < Devise::RegistrationsController
  def new
    super do |user|
      user.charge_and_save_customer
      puts user.inspect
    end
  end
end

我只是想知道这与做的有什么不同:

class Users::RegistrationsController < Devise::RegistrationsController
  def new
    super
    resource.charge_and_save_customer
    puts resource.inspect
  end
end

如果它有用,我已经包含Devise::RegistrationsController下面的父代码:

def new
  build_resource({})
  set_minimum_password_length
  yield resource if block_given?
  respond_with self.resource
end

Answer 1

让我试着解释一下这里发生了什么:

class Users::RegistrationsController < Devise::RegistrationsController
  def new
    super do |user|
      user.charge_and_save_customer
      puts user.inspect
    end
  end
end

当您正在呼叫时super,您将返回到父new操作,因此以下代码将立即执行:

def new
  build_resource({})
  set_minimum_password_length
  yield resource if block_given?
  respond_with self.resource
end

但是等等......这里是一个yield,所以它产生了当前resource的块,你可以认为块像一个方法,它需要一个参数(user),这里resource(来自父)将是参数:

# Here resource is assigned to user
user.charge_and_save_customer
puts user.inspect

现在,由于块完全执行,它将再次开始执行super:

respond_with self.resource