网页视频抓取工具 知乎( 接下来以猫为什么一点也不怕蛇？回答为例，分享一下整个下载过程)

　　网页视频抓取工具 知乎(

接下来以猫为什么一点也不怕蛇？回答为例，分享一下整个下载过程)

　　前言

　　现在允许知乎上传视频，但我不能下载视频。气死我了，只好研究了一下，然后我输入了代码，方便下载和保存视频。

　　接下来，为什么猫根本不怕蛇？以答案为例，分享整个下载过程。

　　相关学习推荐：python视频教程

　　打开F12，找到光标，如下图：

　　然后将光标移动到视频。如下所示：

　　这是什么？视野中出现了一个神秘的链接：，让我们把这个链接复制到浏览器，然后打开：

　　看来这就是我们要找的视频了，别着急，我们先看一下网页的请求，然后你会发现一个很有趣的请求（这里强调）：

　　我们自己来看看数据：

　　{ "playlist": { "ld": { "width": 360, "format": "mp4", "play_url": "https://vdn.vzuu.com/LD/05fc411e-d8e0-11e8-bb8b-0242ac112a0b.mp4?auth_key=1541477643-0-0-987c2c504d14ab1165ce2ed47759d927&expiration=1541477643&disable_local_cache=1", "duration": 17, "size": 1123111, "bitrate": 509, "height": 640 }, "hd": { "width": 720, "format": "mp4", "play_url": "https://vdn.vzuu.com/HD/05fc411e-d8e0-11e8-bb8b-0242ac112a0b.mp4?auth_key=1541477643-0-0-8b8024a22a62f097ca31b8b06b7233a1&expiration=1541477643&disable_local_cache=1", "duration": 17, "size": 4354364, "bitrate": 1974, "height": 1280 }, "sd": { "width": 480, "format": "mp4", "play_url": "https://vdn.vzuu.com/SD/05fc411e-d8e0-11e8-bb8b-0242ac112a0b.mp4?auth_key=1541477643-0-0-5948c2562d817218c9a9fc41abad1df8&expiration=1541477643&disable_local_cache=1", "duration": 17, "size": 1920976, "bitrate": 871, "height": 848 } }, "title": "", "duration": 17, "cover_info": { "width": 720, "thumbnail": "https://pic2.zhimg.com/80/v2-97b9435a0c32d01c7c931bd00120327d_b.jpg", "height": 1280 }, "type": "video", "id": "1039146361396174848", "misc_info": {} }

　　没错，我们要下载的视频就在这里，其中ld代表通用清晰度，sd代表标清，hd代表高清。再次在浏览器中打开对应的链接，然后右击保存即可下载视频。

　　代码

　　知道了整个流程是什么样子的，接下来的压码流程就简单了，不过我这里就不多说了，直接上代码吧：

　　# -*- encoding: utf-8 -*- import re import requests import uuid import datetime class DownloadVideo: __slots__ = [ 'url', 'video_name', 'url_format', 'download_url', 'video_number', 'video_api', 'clarity_list', 'clarity' ] def __init__(self, url, clarity='ld', video_name=None): self.url = url self.video_name = video_name self.url_format = "https://www.zhihu.com/question/\d+/answer/\d+" self.clarity = clarity self.clarity_list = ['ld', 'sd', 'hd'] self.video_api = 'https://lens.zhihu.com/api/videos' def check_url_format(self): pattern = re.compile(self.url_format) matches = re.match(pattern, self.url) if matches is None: raise ValueError( "链接格式应符合:https://www.zhihu.com/question/{number}/answer/{number}" ) return True def get_video_number(self): try: headers = { 'User-Agent': 'Mozilla/5.0 (Macintosh; Intel Mac OS X 10_12_6) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/66.0.3359.181 Safari/537.36' } response = requests.get(self.url, headers=headers) response.encoding = 'utf-8' html = response.text video_ids = re.findall(r'data-lens-id="(\d+)"', html) if video_ids: video_id_list = list(set([video_id for video_id in video_ids])) self.video_number = video_id_list[0] return self raise ValueError("获取视频编号异常:{}".format(self.url)) except Exception as e: raise Exception(e) def get_video_url_by_number(self): url = "{}/{}".format(self.video_api, self.video_number) headers = {} headers['Referer'] = 'https://v.vzuu.com/video/{}'.format( self.video_number) headers['Origin'] = 'https://v.vzuu.com' headers[ 'User-Agent'] = 'Mozilla/5.0 (Windows NT 10.0; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/70.0.3538.67 Safari/537.36' headers['Content-Type'] = 'application/json' try: response = requests.get(url, headers=headers) response_dict = response.json() if self.clarity in response_dict['playlist']: self.download_url = response_dict['playlist'][ self.clarity]['play_url'] else: for clarity in self.clarity_list: if clarity in response_dict['playlist']: self.download_url = response_dict['playlist'][ self.clarity]['play_url'] break return self except Exception as e: raise Exception(e) def get_video_by_video_url(self): response = requests.get(self.download_url) datetime_str = datetime.datetime.now().strftime("%Y-%m-%d %H-%M-%S") if self.video_name is not None: video_name = "{}-{}.mp4".format(self.video_name, datetime_str) else: video_name = "{}-{}.mp4".format(str(uuid.uuid1()), datetime_str) path = "{}".format(video_name) with open(path, 'wb') as f: f.write(response.content) def download_video(self): if self.clarity not in self.clarity_list: raise ValueError("清晰度参数异常,仅支持:ld(普清),sd(标清),hd(高清)") if self.check_url_format(): return self.get_video_number().get_video_url_by_number().get_video_by_video_url() if __name__ == '__main__': a = DownloadVideo('https://www.zhihu.com/question/53031925/answer/524158069') print(a.download_video())

　　结束语

　　代码还有优化的空间。我刚刚下载了答案中的第一个视频。理论上，一个答案下应该有多个视频。如果有什么问题或者建议，可以多交流。

　　相关学习推荐：python视频教程

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