我在控制器中的辅助方法 [英] My helper methods in controller

问题描述

我的应用程序应该呈现 html，以便在用户单击 ajax-link 时进行响应.

My app should render html, to answer when a user clicks ajax-link.

我的控制器:

def create_user
  @user = User.new(params)
  if @user.save
    status = 'success'
    link = link_to_profile(@user) #it's my custom helper in Application_Helper.rb
  else
    status = 'error'
    link = nil
  end

  render :json => {:status => status, :link => link}
end

我的帮手:

  def link_to_profile(user)
    link = link_to(user.login, {:controller => "users", :action => "profile", :id => user.login}, :class => "profile-link")
    return(image_tag("/images/users/profile.png") + " " + link)
  end

我试过这样的方法:

ApplicationController.helpers.link_to_profile(@user)
# It raises: NoMethodError (undefined method `url_for' for nil:NilClass)

和:

class Helper
  include Singleton
  include ActionView::Helpers::TextHelper
  include ActionView::Helpers::UrlHelper
  include ApplicationHelper
end
def help
  Helper.instance    
end

help.link_to_profile(@user)
# It also raises: NoMethodError (undefined method `url_for' for nil:NilClass)

另外，是的，我知道 :helper_method，它可以工作，但我不想用大量这样的方法重载我的 ApplicationController

In addition, yes, I KNOW about :helper_method, and it works, but i don't want to overload my ApplicationController with a plenty of that methods

推荐答案

Oki.让我们回顾一下.您想要访问某些功能/方法，但您不希望这些方法附加到当前对象.

Oki. Let's recap. You want access to certaint functions/methods, but you don't want those methods to be attached to current object.

所以你想要创建一个代理对象，它将代理/委托给这些方法.

So you want to make a proxy object, that will proxy/delegate to those methods.

class Helper
  class << self
   #include Singleton - no need to do this, class objects are singletons
   include ApplicationHelper
   include ActionView::Helpers::TextHelper
   include ActionView::Helpers::UrlHelper
   include ApplicationHelper
  end
end

并且，在控制器中:

class UserController < ApplicationController
  def your_method
    Helper.link_to_profile
  end
end

这种方法的主要缺点是，您无法从辅助函数访问控制器上下文(例如，您将无法访问参数、会话等)

The main disadvantage to this approach is that from the helper functions you won't have access to controller context (EG you won't have access to params, session, etc)

一种折衷方法是在帮助模块中将这些函数声明为私有的，因此，当您包含该模块时，它们在控制器类中也将是私有的.

A compromise would be to declare those functions as private in the helper module, therefore, when you will include the module, they will also be private in the controller class.

module ApplicationHelper
  private
  def link_to_profile
  end
end

class UserController < ApplicationController
  include ApplicationHelper
end

，正如 Damien 指出的那样.

, as Damien pointed out.

更新:您收到url_for"错误的原因是您无权访问控制器的上下文，如上所述.您可以强制将控制器作为参数(Java 样式 ;) )传递，例如:

Update: The reason why you get the 'url_for' error is that you do not have access to controller's context, as stated above. You could force passing the controller as a parameter(Java-style ;) ) like:

Helper.link_to_profile(user, :controller => self)

然后，在你的助手中:

def link_to_profile(user, options)
  options[:controller].url_for(...)
end

或事件更大的黑客，呈现此处.但是，我会推荐将方法设为私有并将它们包含在控制器中的解决方案.

or event a bigger hack, presented here. However, i would reccomend the solution with making methods private and including them in the controller.

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