Rails：为什么我在这个pingback上得到错误的链接？

require 'net/http'
require 'uri'

class Trackback

  @data = { }

  def initialize(link_id)
    link = Link.find(link_id)
    site = Link.website

    if link.nil?
      raise "Could not find link"
    end

    if link.created_at.nil?
      raise "link not published"
    end

    @data =  {
      :title => link.name,
      :excerpt => link.description,
      :url => "http:://www.MyApp.org/links/#{link.to_param}/donations/new",
      :blog_name => "My App"
    }
  end

  def send(trackback_url)
    u = URI.parse trackback_url
    res = Net::HTTP.start(u.host, u.port) do |http|
      http.post(u.request_uri, url_encode(@data), { 'Content-Type' => 'application/x-www-form-urlencoded; charset=utf-8' })
    end
    RAILS_DEFAULT_LOGGER.info "TRACKBACK: #{trackback_url} returned a response of #{res.code} (#{res.body})"
    return res
  end

  private

  def url_encode(data)
    return data.map {|k,v| "#{k}=#{v}"}.join('&')
  end

end