python抓取某学院视频

视频抓取原理：获取所有的知识类别id-》然后获取其子项-》根据子项链接分析获取该类课程数-》循环获取链接指向的视频。需要安装python库：requestspython解析xml使用了网上找的代码。

本来可以再优化。但是懒！

  1 # coding: UTF-8
  2 import os
  3 import sys
  4 import requests
  5 import urllib.request,io
  6 from html.parser import HTMLParser
  7
  8 #全局变量
  9
 10 id_list = set()         #保存视频ID的列表
 11 id_dict = {}            #保存id和对应子视频数目
 12 cookies = {}            #保存cookies
 13
 14 #HTML解析类
 15 class MyHTMLParser(HTMLParser):
 16     def __init__(self, key, attr):
 17         HTMLParser.__init__(self)
 18         self.links = []
 19         self.keys = key
 20         self.attr = attr
 21     def handle_starttag(self, tag, attrs):
 22         #print "Encountered the beginning of a %s tag" % tag
 23         #if tag == "source":
 24         if tag == self.keys:
 25             if len(attrs) == 0:
 26                 pass
 27             else:
 28                 for (variable, value) in attrs:
 29                     #if variable == "src":
 30                     if variable == self.attr:
 31                         self.links.append(value)
 32
 33
 34 #解析cookies字典
 35 def getCookies(cookies_str):
 36     global cookies
 37     for line in cookiesStr.split(‘;‘):
 38         #其设置为1就会把字符串拆分成2份
 39         name, value = line.strip().split(‘=‘, 1)
 40         cookies[name] = value
 41
 42 def getHtml(url, key, value):
 43     global cookies
 44     r = requests.get(url, cookies=cookies)
 45     content = r.content.decode(‘UTF-8‘)
 46     hp = MyHTMLParser("source", "src")
 47     hp.feed(content)
 48     hp.close()
 49     print(hp.links)
 50     for link in hp.links:
 51         link_str = str(link)
 52         if link_str.find(".mp4") >= 0:
 53            downloadFile(link, key, value)
 54         else:
 55            print("没有找到对应视频")
 56
 57
 58 #获取课程数目
 59 def getCourseNum(url):
 60     global cookies
 61     url_list = set()
 62     r = requests.get(url, cookies=cookies)
 63     content = r.content.decode(‘UTF-8‘)
 64     hp = MyHTMLParser("a", "href")
 65     hp.feed(content)
 66     hp.close()
 67     for link in hp.links:
 68         link_str = str(link)
 69         if link_str.find("http://www.jikexueyuan.com/course/") >= 0 and link_str.find(".html?ss=1") >= 0:
 70             url_list.add(link_str)
 71     return url_list.__len__()
 72
 73 #获取所有视频ID，根据目录网页
 74 def getIdList(root):
 75     global cookies
 76     r = requests.get(root, cookies=cookies)
 77     content = r.content.decode(‘UTF-8‘)
 78     hp = MyHTMLParser("a", "href")
 79     hp.feed(content)
 80     hp.close()
 81     #print(hp.links)
 82     #声明引用全局id_list,在最上面定义
 83     global id_list
 84     global id_dict
 85
 86     for link in hp.links:
 87         link_str = str(link)
 88         if link_str.find("http://www.jikexueyuan.com/course/") >= 0 and link_str.find(".html")>= 0:
 89             #print(link)
 90             c_id = link_str.lstrip("http://www.jikexueyuan.com/course/").rstrip(".html")
 91             if c_id not in id_list:
 92                 id_dict[c_id] = getCourseNum(link_str)
 93                 print(c_id, id_dict[c_id])
 94             id_list.add(c_id)
 95     print(id_dict)
 96
 97 def downloadFile(url, key, value):
 98     #url = ‘http://cv4.jikexueyuan.com/10de45bbf83e450ff5e11ff4599d7166/201603202253/cocos2d-x/course_712/01/video/c712b_01_h264_sd_960_540.mp4‘
 99     r = requests.get(url)
100     file_name = str(key)+"_"+str(value)+".mp4"
101     with open(file_name, "wb") as code:
102          code.write(r.content)
103
104 if __name__=="__main__":
105     count = 0
106     #解析cookies 利用免费时间下载需要视频，需要账号的cookies
107     cookiesStr = "通过谷歌浏览器可以获取"
108     getCookies(cookiesStr)
109
110
111     root = "http://ke.jikexueyuan.com/xilie/331?huodong=shequn_0307"
112     getIdList(root)
113
114     head = "http://www.jikexueyuan.com/course/"
115
116     for key in id_dict:
117         if id_dict[key] <= 0:
118             print(id_dict[key],"没有数据")
119             break
120         for i in range(1, id_dict[key]+1):
121             url = head+key+"_"+str(i)+".html?ss=1"
122             print("下载:")
123             print(url)
124             count += 1
125             getHtml(url, key, i)
126     print("视频总数：")
127     print(count)

可以优化的点：由于没有获取到每个视频的名字，看起来很不爽。可以获取视频的名字，然后根据类别建立文件夹。这样保存起来更方便观看。

cookies真的可以获取直接用。那么意味着如果截取用户浏览器登陆信息也可以直接登陆并获取有用的信息。哪些黑客获取cookies然后盗取用户信息原理就是这样的么？有意思。