python爬虫调度器用法及实例代码

# coding: utf-8
new_urls = set()
data = {}
class SpiderMan(object):
 def __init__(self):
  #调度器内包含其它四个元件，在初始化调度器的时候也要建立四个元件对象的实例
  self.manager = UrlManager()
  self.downloader = HtmlDownloader()
  self.parser = HtmlParser()
  self.output = DataOutput()
 def spider(self, origin_url):
  #添加初始url
  self.manager.add_new_url(origin_url)
  #下面进入主循环，暂定爬取页面总数小于100
  num = 0
  while(self.manager.has_new_url() and self.manager.old_url_size()<100):
   try:
    num = num + 1
    print "正在处理第{}个链接".format(num)
    #从新url仓库中获取url
    new_url = self.manager.get_new_url()
    #调用html下载器下载页面
    html = self.downloader.download(new_url)
    #调用解析器解析页面，返回新的url和data
    try:
     new_urls, data = self.parser.parser(new_url, html)
    except Exception, e:
     print e
    for url in new_urls:
     self.manager.add_new_url(url)
    #将已经爬取过的这个url添加至老url仓库中
    self.manager.add_old_url(new_url)
    #将返回的数据存储至文件
     self.output.store_data(data)
     print "store data succefully"
    print "第{}个链接已经抓取完成".format(self.manager.old_url_size())
   except Exception, e:
    print e
  #爬取循环结束的时候将存储的数据输出至文件
  self.output.output_html()