python获取知乎问题答案并转换为MarkDown文件

前期准备

• python2.7
• html2text
• markdownpad(这里随意，只要可以支持md就行)
• 会抓包
• 最重要的是你要有代理，因为知乎开始封IP了

原理

原理说起来很简单：获取请求到的内容的BODY部分，然后重新构建一个HTML文件，接着利用html2text这个模块将其转换为markdown文件，最后对图片及标题按照markdown的格式做一些处理就好了。目前应用的场景主要是在知乎。

代码实现

获取知乎答案

写代码的时候，主要考虑了两种使用场景。第一，获取某一特定答案的数据然后进行转换；第二，获取某一个问题的所有答案进行然后挨个进行转换，在这里可以 通过赞同数来对要获取的答案进行质量控制。

某一个特定答案的数据获取

url：https://www.zhihu.com/question/27621722/answer/48658220
'''
（前面那个是问题ID，后边的是答案ID）
'''

这一数据的获取我这里分为了两个部分，第一部分请求上述网址，拿到答案主体数据以及赞同数，第二部分请求下面这个接口：

https://www.zhihu.com/api/v4/answers/48658220

为什么会这样？因为这个接口得到的答案正文数据不是完整数据，所以只能分两步了。

某一个特定答案的数据获取

这一个数据就可以通过很简单的方式得到了，接口如下：

https://www.zhihu.com/api/v4/questions/27621722/answers?sort_by=default&include=data%5B%2A%5D.is_normal%2Cis_collapsed%2Ccollapse_reason%2Cis_sticky%2Ccollapsed_by%2Csuggest_edit%2Ccomment_count%2Ccan_comment%2Ccontent%2Ceditable_content%2Cvoteup_count%2Creshipment_settings%2Ccomment_permission%2Cmark_infos%2Ccreated_time%2Cupdated_time%2Crelationship.is_authorized%2Cis_author%2Cvoting%2Cis_thanked%2Cis_nothelp%2Cupvoted_followees%3Bdata%5B%2A%5D.author.follower_count%2Cbadge%5B%3F%28type%3Dbest_answerer%29%5D.topics&limit=20&offset=3

返回的都是JSON数据，很方便获取。但是这里有一个地方需要注意，从这里面取的答案正文数据就是文本数据，不是一个完整的html文件，所以需要在构造一下。

保存的字段

• author_name 回答用户名
• answer_id 答案ID
• question_id 问题ID
• question_title 问题
• vote_up_count 赞同数
• create_time 创建时间
• 答案主体

主脚本：zhihu.py

import os
import re
import json
import requests
import html2text
from parse_content import parse
​
"""
just for study and fun
Talk is cheap
show me your code
"""
​
class ZhiHu(object):
 def __init__(self):
 self.request_content = None
​
 def request(self, url, retry_times=10):
 header = {
 'User-Agent': 'Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/57.0.2987.133 Safari/537.36',
 'authorization': 'oauth c3cef7c66a1843f8b3a9e6a1e3160e20',
 'Host': 'www.zhihu.com'
 }
 times = 0
 while retry_times>0:
 times += 1
 print 'request %s, times: %d' %(url, times)
 try:
 ip = 'your proxy ip'
 if ip:
 proxy = {
 'http': 'http://%s' % ip,
 'https': 'http://%s' % ip
 }
 self.request_content = requests.get(url, headers=header, proxies=proxy, timeout=10).content
 except Exception, e:
 print e
 retry_times -= 1
 else:
 return self.request_content
​
 def get_all_answer_content(self, question_id, flag=2):
 first_url_format = 'https://www.zhihu.com/api/v4/questions/{}/answers?sort_by=default&include=data%5B%2A%5D.is_normal%2Cis_collapsed%2Ccollapse_reason%2Cis_sticky%2Ccollapsed_by%2Csuggest_edit%2Ccomment_count%2Ccan_comment%2Ccontent%2Ceditable_content%2Cvoteup_count%2Creshipment_settings%2Ccomment_permission%2Cmark_infos%2Ccreated_time%2Cupdated_time%2Crelationship.is_authorized%2Cis_author%2Cvoting%2Cis_thanked%2Cis_nothelp%2Cupvoted_followees%3Bdata%5B%2A%5D.author.follower_count%2Cbadge%5B%3F%28type%3Dbest_answerer%29%5D.topics&limit=20&offset=3'
 first_url = first_url_format.format(question_id)
 response = self.request(first_url)
 if response:
 contents = json.loads(response)
 print contents.get('paging').get('is_end')
 while not contents.get('paging').get('is_end'):
 for content in contents.get('data'):
 self.parse_content(content, flag)
 next_page_url = contents.get('paging').get('next').replace('http', 'https')
 contents = json.loads(self.request(next_page_url))
 else:
 raise ValueError('request failed, quit......')
​
 def get_single_answer_content(self, answer_url, flag=1):
 all_content = {}
 question_id, answer_id = re.findall('https://www.zhihu.com/question/(\d+)/answer/(\d+)', answer_url)[0]
​
 html_content = self.request(answer_url)
 if html_content:
 all_content['main_content'] = html_content
 else:
 raise ValueError('request failed, quit......')
​
 ajax_answer_url = 'https://www.zhihu.com/api/v4/answers/{}'.format(answer_id)
 ajax_content = self.request(ajax_answer_url)
 if ajax_content:
 all_content['ajax_content'] = json.loads(ajax_content)
 else:
 raise ValueError('request failed, quit......')
​
 self.parse_content(all_content, flag, )
​
 def parse_content(self, content, flag=None):
 data = parse(content, flag)
 self.transform_to_markdown(data)
​
 def transform_to_markdown(self, data):
 content = data['content']
 author_name = data['author_name']
 answer_id = data['answer_id']
 question_id = data['question_id']
 question_title = data['question_title']
 vote_up_count = data['vote_up_count']
 create_time = data['create_time']
​
 file_name = u'%s--%s的回答[%d].md' % (question_title, author_name,answer_id)
 folder_name = u'%s' % (question_title)
​
 if not os.path.exists(os.path.join(os.getcwd(),folder_name)):
 os.mkdir(folder_name)
 os.chdir(folder_name)
​
 f = open(file_name, "wt")
 f.write("-" * 40 + "\n")
 origin_url = 'https://www.zhihu.com/question/{}/answer/{}'.format(question_id, answer_id)
 f.write("## 本答案原始链接: " + origin_url + "\n")
 f.write("### question_title: " + question_title.encode('utf-8') + "\n")
 f.write("### Author_Name: " + author_name.encode('utf-8') + "\n")
 f.write("### Answer_ID: %d" % answer_id + "\n")
 f.write("### Question_ID %d: " % question_id + "\n")
 f.write("### VoteCount: %s" % vote_up_count + "\n")
 f.write("### Create_Time: " + create_time + "\n")
 f.write("-" * 40 + "\n")
​
 text = html2text.html2text(content.decode('utf-8')).encode("utf-8")
 # 标题
 r = re.findall(r'\*\*(.*?)\*\*', text, re.S)
 for i in r:
 if i != " ":
 text = text.replace(i, i.strip())
​
 r = re.findall(r'_(.*)_', text)
 for i in r:
 if i != " ":
 text = text.replace(i, i.strip())
 text = text.replace('_ _', '')
​
 # 图片
 r = re.findall(r'!\[\]\((?:.*?)\)', text)
 for i in r:
 text = text.replace(i, i + "\n\n")
​
 f.write(text)
​
 f.close()
​
​
if __name__ == '__main__':
 zhihu = ZhiHu()
 url = 'https://www.zhihu.com/question/27621722/answer/105331078'
 zhihu.get_single_answer_content(url)
​
 # question_id = '27621722'
 # zhihu.get_all_answer_content(question_id)

zhihu.py为主脚本，内容很简单，发起请求，调用解析函数进行解析，最后再进行保存。

解析函数脚本：parse_content.py

import time
from bs4 import BeautifulSoup
 
 
def html_template(data):
 # api content
 html = '''
 <html>
 <head>
 <body>
 %s
 </body>
 </head>
 </html>
 ''' % data
 return html
 
 
def parse(content, flag=None):
 data = {}
 if flag == 1:
 # single
 main_content = content.get('main_content')
 ajax_content = content.get('ajax_content')
 
 soup = BeautifulSoup(main_content.decode("utf-8"), "lxml")
 answer = soup.find("span", class_="RichText CopyrightRichText-richText")
 
 author_name = ajax_content.get('author').get('name')
 answer_id = ajax_content.get('id')
 question_id = ajax_content.get('question').get('id')
 question_title = ajax_content.get('question').get('title')
 vote_up_count = soup.find("meta", itemprop="upvoteCount")["content"]
 create_time = time.strftime("%Y-%m-%d %H:%M:%S", time.localtime(ajax_content.get('created_time')))
 
 
 else:
 # all
 answer_content = content.get('content')
 
 author_name = content.get('author').get('name')
 answer_id = content.get('id')
 question_id = content.get('question').get('id')
 question_title = content.get('question').get('title')
 vote_up_count = content.get('voteup_count')
 create_time = time.strftime("%Y-%m-%d %H:%M:%S", time.localtime(content.get('created_time')))
 
 content = html_template(answer_content)
 soup = BeautifulSoup(content, 'lxml')
 answer = soup.find("body")
 
 print author_name,answer_id,question_id,question_title,vote_up_count,create_time
 # 这里非原创，看了别人的代码，修改了一下
 soup.body.extract()
 soup.head.insert_after(soup.new_tag("body", **{'class': 'zhi'}))
 
 soup.body.append(answer)
 
 img_list = soup.find_all("img", class_="content_image lazy")
 for img in img_list:
 img["src"] = img["data-actualsrc"]
 img_list = soup.find_all("img", class_="origin_image zh-lightbox-thumb lazy")
 for img in img_list:
 img["src"] = img["data-actualsrc"]
 noscript_list = soup.find_all("noscript")
 for noscript in noscript_list:
 noscript.extract()
 
 data['content'] = soup
 data['author_name'] = author_name
 data['answer_id'] = answer_id
 data['question_id'] = question_id
 data['question_title'] = question_title
 data['vote_up_count'] = vote_up_count
 data['create_time'] = create_time
 
 return data

parse_content.py主要负责构造新的html，然后对其进行解析，获取数据。

测试结果展示

一定要联网！

一定要联网！

一定要联网！