爬虫运行失败，craw 1 : https://baike.baidu.com/item/Python/407313?fr=aladdin craw failed

Question

使用的是python2.7

#主函数spider_main.py
# coding :utf8
from baike_spider import url_manager,html_downloader,html_outputer,\
    html_parser
class  SpiderMain(object):
    def __init__(self):
        self.urls = url_manager.UrlManager()
        self.downloader = html_downloader.HtmlDownloader()
        self.parser = html_parser.HtmlParser()
        self.outputer = html_outputer.HtmlOutputer()

    def craw(self,root_url):
        count = 1
        self.urls.add_new_url(root_url)
        while self.urls.has_new_url():
            try:

                new_url = self.urls.get_new_url()
                print 'craw %d : %s ' % (count, new_url)
                html_cont = self.downloader.download(new_url)
                new_urls, new_data = self.parser.parse(new_url, html_cont)
                self.urls.add_new_urls(new_urls)
                self.outputer.collect_data(new_data)

                if count == 1000:
                    break

                count = count +1
            except:
                print 'craw failed'
        self.outputer.output_html()

if __name__ == "__main__":
    root_url = "https://baike.baidu.com/item/Python/407313?fr=aladdin"
    obj_spider = SpiderMain( )
    obj_spider.craw(root_url)

#url_manager.py
# coding : utf8
class UrlManager (object):
    def __init__(self):
        self.new_urls = set()
        self.old_urls = set()

    def add_new_url(self,url):
       if url is None:
            return
       if url not in self.new_urls  and  url not in  self.old_urls:
            self.new_urls.add(url)

    def add_new_urls(self,urls):
        if urls is None or len (urls) == 0:
            return
        for url in urls:
            self.add_new_url(url)

    def has_new_url(self):
        return len(self.new_urls) !=0

    def get_new_url(self):
        new_url = self.new_urls.pop()
        self.old_urls.add(new_url)
        return new_url

# html_parser.py
# coding : utf8
import re
import urlparse
from bs4 import BeautifulSoup
class HtmlParser (object):
   def _get_new_urls(self,page_url,soup):
       new_urls = set ()
       #/item/Python/407313?fr=aladdin
       links = soup.find_all('a',href=re.compile(r"/item/Python/\d+\?fr=aladdin"))
       for link in links:
           new_url = link['href']
           new_full_url = urlparse.urljoin(page_url,new_url)
           new_urls.add(new_full_url)
       return new_urls

   def  _get_new_date(self,page_url,soup):
       res_date={}

       # url
       res_date['url'] =page_url

       #<dd class="lemmaWgt-lemmaTitle-title"><h1>Python</h1>

       title_node = soup.find('dd',class_="lemmaWgt-lemmaTitle-title").find("h1")
       res_date['title'] = title_node.get_text()
        #<div class="lemma-summary" label-module="lemmaSummary">
       summary_node = soup.find('div',class_="lemma-summary")
       res_date['summary'] = summary_node.get_text()

       return res_date



   def parse(self,page_url,html_cont):
      if page_url is None or html_cont is None:
          return

      soup = BeautifulSoup(html_cont,'html.parser',from_encoding='utf-8')
      new_urls = self._get_new_urls(page_url,soup)
      new_data = self._get_new_data(page_url,soup)
      return new_urls,new_data


#html_outputer.py
# coding : utf8
import re
import urlparse
from bs4 import BeautifulSoup
class HtmlParser (object):
   def _get_new_urls(self,page_url,soup):
       new_urls = set ()
       #/item/Python/407313?fr=aladdin
       links = soup.find_all('a',href=re.compile(r"/item/Python/\d+\?fr=aladdin"))
       for link in links:
           new_url = link['href']
           new_full_url = urlparse.urljoin(page_url,new_url)
           new_urls.add(new_full_url)
       return new_urls

   def  _get_new_date(self,page_url,soup):
       res_date={}

       # url
       res_date['url'] =page_url

       #<dd class="lemmaWgt-lemmaTitle-title"><h1>Python</h1>

       title_node = soup.find('dd',class_="lemmaWgt-lemmaTitle-title").find("h1")
       res_date['title'] = title_node.get_text()
        #<div class="lemma-summary" label-module="lemmaSummary">
       summary_node = soup.find('div',class_="lemma-summary")
       res_date['summary'] = summary_node.get_text()

       return res_date



   def parse(self,page_url,html_cont):
      if page_url is None or html_cont is None:
          return

      soup = BeautifulSoup(html_cont,'html.parser',from_encoding='utf-8')
      new_urls = self._get_new_urls(page_url,soup)
      new_data = self._get_new_data(page_url,soup)
      return new_urls,new_data


#html_downloader.py

# coding : utf8
import urllib2
class HtmlDownloader (object):


    def download(self,url):
        if url is None :
            return None

        response=urllib2.urlopen(url)

        if response.getcode() != 200:
            return None

        return response.read()