一个简单的python爬虫,爬取知乎

# -*- coding:utf-8 -*-

from spider import SpiderHTML
from multiprocessing import Pool
import sys,urllib,http,os,random,re,time
__author__ = 'waiting'
'''
使用了第三方的类库 BeautifulSoup4，请自行安装
需要目录下的spider.py文件
运行环境：python3.4,windows7
'''

#收藏夹的地址
url = 'https://www.zhihu.com/collection/30822111'  #page参数改为代码添加

#本地存放的路径,不存在会自动创建
store_path = 'E:\\zhihu\收藏夹\\会员才知道的世界'

class zhihuCollectionSpider(SpiderHTML):
  def __init__(self,pageStart, pageEnd, url):
    self._url = url
    self._pageStart = int(pageStart)
    self._pageEnd = int(pageEnd)+1
    self.downLimit = 0            #低于此赞同的答案不收录

  def start(self):
    for page in range(self._pageStart,self._pageEnd):    #收藏夹的页数
      url = self._url + '?page='+str(page)
      content = self.getUrl(url)
      questionList = content.find_all('div',class_='zm-item')
      for question in questionList:            #收藏夹的每个问题
        Qtitle = question.find('h2',class_='zm-item-title')
        if Qtitle is None:                #被和谐了
          continue

        questionStr = Qtitle.a.string
        Qurl = 'https://www.zhihu.com'+Qtitle.a['href']  #问题题目
        Qtitle = re.sub(r'[\\/:*?"<>]','#',Qtitle.a.string)      #windows文件/目录名不支持的特殊符号
        try:
          print('-----正在获取问题:'+Qtitle+'-----')    #获取到问题的链接和标题，进入抓取
        except UnicodeEncodeError:
          print(r'---问题含有特殊字符无法显示---')
        try:
          Qcontent = self.getUrl(Qurl)
        except:
          print('!!!!获取出错!!!!!')
          pass
        answerList = Qcontent.find_all('div',class_='zm-item-answer  zm-item-expanded')
        self._processAnswer(answerList,Qtitle)            #处理问题的答案
        time.sleep(5)


  def _processAnswer(self,answerList,Qtitle):
    j = 0      
    for answer in answerList:
      j = j + 1
      
      upvoted = int(answer.find('span',class_='count').string.replace('K','000'))   #获得此答案赞同数
      if upvoted < self.downLimit:
        continue
      authorInfo = answer.find('div',class_='zm-item-answer-author-info')        #获取作者信息
      author = {'introduction':'','link':''}
      try:
        author['name'] = authorInfo.find('a',class_='author-link').string       #获得作者的名字
        author['introduction'] = str(authorInfo.find('span',class_='bio')['title']) #获得作者的简介
        author['link'] = authorInfo.find('a',class_='author-link')['href']      
      except AttributeError:
        author['name'] = '匿名用户'+str(j)
      except TypeError:                                  #简介为空的情况
        pass                                     #匿名用户没有链接

      file_name = os.path.join(store_path,Qtitle,'info',author['name']+'_info.txt')
      if os.path.exists(file_name):              #已经抓取过
        continue
  
      self.saveText(file_name,'{introduction}\r\n{link}'.format(**author))      #保存作者的信息
      print('正在获取用户`{name}`的答案'.format(**author))
      answerContent = answer.find('div',class_='zm-editable-content clearfix')
      if answerContent is None:                #被举报的用户没有答案内容
        continue
  
      imgs = answerContent.find_all('img')
      if len(imgs) == 0:                    #答案没有上图
        pass
      else:
        self._getImgFromAnswer(imgs,Qtitle,**author)

  #收录图片
  def _getImgFromAnswer(self,imgs,Qtitle,**author):
    i = 0
    for img in imgs:
      if 'inline-image' in img['class']:          #不抓取知乎的小图
        continue
      i = i + 1
      imgUrl = img['src']
      extension = os.path.splitext(imgUrl)[1]
      path_name = os.path.join(store_path,Qtitle,author['name']+'_'+str(i)+extension)
      try:
        self.saveImg(imgUrl,path_name)          #捕获各种图片异常，流程不中断
      except:                  
        pass
        
  #收录文字
  def _getTextFromAnswer(self):
    pass

#命令行下运行，例：zhihu.py 1 5   获取1到5页的数据
if __name__ == '__main__':
  page, limit, paramsNum= 1, 0, len(sys.argv)
  if paramsNum>=3:
    page, pageEnd = sys.argv[1], sys.argv[2]
  elif paramsNum == 2:
    page = sys.argv[1]
    pageEnd = page
  else:
    page,pageEnd = 1,1

  spider = zhihuCollectionSpider(page,pageEnd,url)
  spider.start()