rails 中如何直接获得某个url的内容

在rails中怎么直接读取其他网站上的网页内容？

http://www.ruby-doc.org/core/classes/Net/HTTP.html

Examples
Getting Document From WWW Server

Example 1: Simple GET+print

    require 'net/http'
    Net::HTTP.get_print 'www.example.com', '/index.html'

Example 2: Simple GET+print by URL

    require 'net/http'
    require 'uri'
    Net::HTTP.get_print URI.parse('http://www.example.com/index.html')

Example 3: More generic GET+print

    require 'net/http'
    require 'uri'

    url = URI.parse('http://www.example.com/index.html')
    res = Net::HTTP.start(url.host, url.port) {|http|
      http.get('/index.html')
    }
    puts res.body

Example 4: More generic GET+print

    require 'net/http'

    url = URI.parse('http://www.example.com/index.html')
    req = Net::HTTP::Get.new(url.path)
    res = Net::HTTP.start(url.host, url.port) {|http|
      http.request(req)
    }
    puts res.body