socialforge/app/api/mobile/entities/news.rb

module Mobile
  module Entities
    class News < Grape::Entity
      def self.news_expose(field)
        expose field do |f,opt|
          if f.is_a?(Hash) && f.key?(field)
            f[field]
          elsif f.is_a?(Hash) && !f.key?(field)
            n = f[:news]
            comments = f[:comments]
            if n.is_a?(::News)
              n.send(field) if n.respond_to?(field)
            end

          end
        end
      end

      #新闻标题
      news_expose :title

      expose :author,using: Mobile::Entities::User do |f, opt|
        n = f[:news]
        n.author if n.respond_to?(:author)
      end
      #作者id
      news_expose :author_id
      #作者名
      news_expose :author_name
      #新闻内容
      news_expose :description
      #发布时间
      news_expose :created_on
      #评论数量
      news_expose :comments_count
      #评论
      news_expose :comments


    end
  end
end