在ruby方法中定义自定义回调

Question

我有很多服务类，其中call方法的参数有变化。

我想在每个call方法的末尾调用函数notify。我不想修改这些服务类，但我愿意修改基类。

我在玩ActiveSupport::Callbacks，但它没有服务于不修改服务类的目的。

require 'active_support' 
class Base 
    include ActiveSupport::Callbacks 
    define_callbacks :notifier 

    set_callback :notifier, :after do |object| 
    notify() 
    end 

    def notify 
    puts "notified successfully" 
    end 
end 

class NewPost < Base 
    def call 
    puts "Creating new post on WordPress" 
    # run_callbacks :notifier do 
    # puts "notifying....." 
    # end 
    end 
end 

class EditPost < Base 
    def call 
    puts "Editing the post on WordPress" 
    # run_callbacks :notifier do 
    # puts "notified successfully" 
    # end 
    end 
end 

person = NewPost.new 
person.call 

问题为了运行回调，我需要取消对注释的代码。但在这里你可以看到我需要修改现有的类来添加run_callbacks块。但那不是我想要的。我可以轻松地调用notify方法，而不会增加这种复杂性。

任何人都可以建议我怎么才能达到解决方案的红宝石方式？

Answer 1

我会做这样的事情：

require 'active_support' 
class Base 
    include ActiveSupport::Callbacks 
    define_callbacks :notifier 

    set_callback :notifier, :after do |object| 
    notify() 
    end 

    def notify 
    puts "notified successfully" 
    end 

    def call 
    run_callbacks :notifier do 
     do_call 
    end 
    end 

    def do_call 
    raise 'this should be implemented in children classes' 
    end 
end 

class NewPost < Base 
    def do_call 
    puts "Creating new post on WordPress" 
    end 
end 

person = NewPost.new 
person.call 

另一种解决方案，而不的ActiveSupport：

module Notifier 
    def call 
    super 
    puts "notified successfully" 
    end 
end 


class NewPost 
    prepend Notifier 

    def call 
    puts "Creating new post on WordPress" 
    end 
end 

NewPost.new.call 

您应该检查你的Ruby版本prepend是一个 “新” 的方法（2.0）