Ruby on rails Rails：在json中调用模型方法（：methods=>；[：Model\u method]）

我在Model

image\u-url

和

thumb\u-url

中定义了两种方法来获取图像和拇指的绝对

url

并在controller

.to_json（）

方法中调用它们

当我查看

Json

响应时，它只显示

image\u url

而不是

thumb\u url

请告诉我我做错了什么

型号：

class Post < ActiveRecord::Base
  include Rails.application.routes.url_helpers

    validates :image, presence: true

      has_attached_file :image, styles: { :medium => "640x", thumb: "100x100#" } # # means crop the image
        validates_attachment_content_type :image, :content_type => /\Aimage\/.*\Z/

  def image_url
   relative_path =  image.url(:medium)
   self.add_host_prefix relative_path
  end

 def thumb_url
   relative_path = image.url(:thumb)
   self.add_host_prefix relative_path
 end

  def add_host_prefix(url)
    URI.join(root_url, url).to_s
  end
end

class Api::ImagesController < ApplicationController

  def index
    @posts =  Post.all.order(id: :desc)
    paginated_records = @posts.paginate(:page => params[:page], :per_page => params[:per_page])
    @posts = with_pagination_info( paginated_records )
    render :json => @posts.to_json(:methods => [:thumb_url], :methods =>[:image_url])
  end
end

"data": [{
"id": 23,
"caption": "World Top View",
"created_at": "2015-09-17T14:10:57.278Z",
"updated_at": "2015-09-17T14:10:57.278Z",
"image_file_name": "world.topo.bathy.200401.3x21600x10800.jpg",
"image_content_type": "image/jpeg",
"image_file_size": 29698041,
"image_updated_at": "2015-09-17T14:10:36.975Z",
"image_url": "http://localhost:3000/system/posts/images/000/000/023/medium/world.topo.bathy.200401.3x21600x10800.jpg?1442499036"}

---

不能将两个

：方法
键传递到哈希中，只使用最后一个键。请记住，散列的键必须是唯一的。如果你想要多种方法，你应该

render :json => @posts.to_json(:methods => [:thumb_url, :image_url])