Python中如何使用requsets获取知乎最有价值的内容

本篇文章为大家展示了Python中如何使用requsets获取知乎最有价值的内容，内容简明扼要并且容易理解，绝对能使你眼前一亮，通过这篇文章的详细介绍希望你能有所收获。

一 前言 
  使用requsets 爬取知乎中最优价值的内容，写一段获取内容的python程序。

二 践行

1. #!/usr/bin/env python
   

2. #-*- coding:utf-8 -*-
   

3. import re
   

4. import requests
   

5. import os
   

6. from urlparse import urlsplit
   

7. from os.path import basename

8. def getHtml(url):
   

9.     session = requests.Session()
   

10.     # 模拟浏览器访问
    

11.     header = {
    

12.         'User-Agent': "Mozilla/5.0 (Windows NT 6.3; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/45.0.2454.101 Safari/537.36",
    

13.         'Accept-Encoding': 'gzip, deflate'}
    

14.     res = session.get(url, headers=header)
    

15.     if res.status_code == 200:
    

16.         content = res.content
    

17.     else:
    

18.         content = ''
    

19.     return content
    

20. 
    

21. def mkdir(path):
    

22.     if not os.path.exists(path):
    

23.         print '新建文件夹:', path
    

24.         os.makedirs(path)
    

25.         return True
    

26.     else:
    

27.         print u"图片存放于:", os.getcwd() + os.sep + path
    

28.         return False
    

29. 
    

30. def download_pic(img_lists, dir_name):
    

31.     print "一共有 {num} 张照片".format(num=len(img_lists))
    

32.     for image_url in img_lists:
    

33.         response = requests.get(image_url, stream=True)
    

34.         if response.status_code == 200:
    

35.             image = response.content
    

36.         else:
    

37.             continue
    

38.         file_name = dir_name + os.sep + basename(urlsplit(image_url)[2])
    

39.         try:
    

40.             with open(file_name, "wb") as picture:
    

41.                 picture.write(image)
    

42.         except IOError:
    

43.             print("IO Error\n")
    

44.             return
    

45.         finally:
    

46.             picture.close
    

47.             print "下载 {pic_name} 完成!".format(pic_name=file_name)
    

48. 
    

49. def getAllImg(html):
    

50.     # 利用正则表达式把源代码中的图片地址过滤出来
    

51.     #reg = r'data-actualsrc="(.*?)">'
    

52.     reg = r'https://pic\d.zhimg.com/[a-fA-F0-9]{5,32}_\w+.jpg'
    

53.     imgre = re.compile(reg, re.S)
    

54.     tmp_list = imgre.findall(html) # 表示在整个网页中过滤出所有图片的地址，放在imglist中
    

55.     # 清理掉头像和去重 获取data-original的内容
    

56.     tmp_list = list(set(tmp_list)) # 去重
    

57.     imglist = []
    

58.     for item in tmp_list:
    

59.         if item.endswith('r.jpg'):
    

60.             img_list.append(item)
    

61.     print 'num : %d' % (len(imglist))
    

62.     return imglist
    

63. 
    

64. 
    

65. if __name__ == '__main__':
    

66.     question_id = 35990613
    

67.     zhihu_url = "https://www.zhihu.com/question/{qid}".format(qid=question_id)
    

68.     html_content = getHtml(zhihu_url)
    

69.     path = 'zhihu_pic'
    

70.     mkdir(path) # 创建本地文件夹
    

71.     img_list = getAllImg(html_content) # 获取图片的地址列表
    

72.     download_pic(img_list, path)       # 保存图片

本代码还存在一些不足的地方，无法完全获取全部的图片，需要在兼容 自动点击 ”更多“ 加载更多答案。
代码第二版解决了第一版代码中不能自动加载的问题。

1. #!/usr/bin/env python
   

2. #-*- coding:utf-8 -*-
   

3. import re
   

4. import requests
   

5. import os
   

6. from urlparse import urlsplit
   

7. from os.path import basename
   

8. 
   

9. headers = {
   

10.     'User-Agent': "Mozilla/5.0 (Windows NT 6.3; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/45.0.2454.101 Safari/537.36",
    

11.     'Accept-Encoding': 'gzip, deflate'}
    

12. 
    

13. 
    

14. def mkdir(path):
    

15.     if not os.path.exists(path):
    

16.         print '新建文件夹:', path
    

17.         os.makedirs(path)
    

18.         return True
    

19.     else:
    

20.         print u"图片存放于:", os.getcwd() + os.sep + path
    

21.         return False
    

22. 
    

23. 
    

24. def download_pic(img_lists, dir_name):
    

25.     print "一共有 {num} 张照片".format(num=len(img_lists))
    

26.     for image_url in img_lists:
    

27.         response = requests.get(image_url, stream=True)
    

28.         if response.status_code == 200:
    

29.             image = response.content
    

30.         else:
    

31.             continue
    

32.         file_name = dir_name + os.sep + basename(urlsplit(image_url)[2])
    

33.         try:
    

34.             with open(file_name, "wb") as picture:
    

35.                 picture.write(image)
    

36.         except IOError:
    

37.             print("IO Error\n")
    

38.             continue
    

39.         finally:
    

40.             picture.close
    

41.             print "下载 {pic_name} 完成!".format(pic_name=file_name)
    

42. 
    

43. 
    

44. def get_image_url(qid, headers):
    

45.     # 利用正则表达式把源代码中的图片地址过滤出来
    

46.     #reg = r'data-actualsrc="(.*?)">'
    

47.     tmp_url = "https://www.zhihu.com/node/QuestionAnswerListV2"
    

48.     size = 10
    

49.     image_urls = []
    

50.     session = requests.Session()
    

51.     # 利用循环自动完成需要点击 “更多” 获取所有答案，每个分页作为一个answer集合。

52.     while True:
    

53.         postdata = {'method': 'next', 'params': '{"url_token":' +
    

54.                     str(qid) + ',"pagesize": "10",' + '"offset":' + str(size) + "}"}
    

55.         page = session.post(tmp_url, headers=headers, data=postdata)
    

56.         ret = eval(page.text)
    

57.         answers = ret['msg']

58.         size += 10
    

59.         if not answers:
    

60.             print "图片URL获取完毕, 页数: ", (size - 10) / 10
    

61.             return image_urls
    

62.         #reg = r'https://pic\d.zhimg.com/[a-fA-F0-9]{5,32}_\w+.jpg'
    

63.         imgreg = re.compile('data-original="(.*?)"', re.S)
    

64.         for answer in answers:
    

65.             tmp_list = []
    

66.             url_items = re.findall(imgreg, answer)
    

67.             for item in url_items: # 这里去掉得到的图片URL中的转义字符'\\'
    

68.                 image_url = item.replace("\\", "")
    

69.                 tmp_list.append(image_url)
    

70.             # 清理掉头像和去重 获取data-original的内容
    

71.             tmp_list = list(set(tmp_list)) # 去重
    

72.             for item in tmp_list:
    

73.                 if item.endswith('r.jpg'):
    

74.                     print item
    

75.                     image_urls.append(item)
    

76.         print 'size: %d, num : %d' % (size, len(image_urls))
    

77. 
    

78. 
    

79. if __name__ == '__main__':
    

80.     question_id = 26037846
    

81.     zhihu_url = "https://www.zhihu.com/question/{qid}".format(qid=question_id)
    

82.     path = 'zhihu_pic'
    

83.     mkdir(path) # 创建本地文件夹
    

84.     img_list = get_image_url(question_id, headers) # 获取图片的地址列表
    

85.     download_pic(img_list, path) # 保存图片

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