如何用Python制作一个MOOC公开课下载器

这篇文章主要介绍"如何用Python制作一个MOOC公开课下载器"，在日常操作中，相信很多人在如何用Python制作一个MOOC公开课下载器问题上存在疑惑，小编查阅了各式资料，整理出简单好用的操作方法，希望对大家解答"如何用Python制作一个MOOC公开课下载器"的疑惑有所帮助！接下来，请跟着小编一起来学习吧！

开发工具

Python版本：3.7.8

相关模块：

DecryptLogin模块；

tqdm模块；

click模块；

argparse模块；

以及一些python自带的模块。

环境搭建

安装Python并添加到环境变量，pip安装需要的相关模块即可。

先睹为快

运行方式：

python moocdl.py --url 课程链接

效果如下：

moocdl

随便挑的一个课程测试的，结果是m3u8格式的，所以下载起来有点慢。默认会把所有的课件这些东西也一起下载下来放到对应的目录。

原理简介

首先，我们需要先模拟登录中国大学MOOC，这样才能下载对应的课程资料，这里借助公众号之前开源的DecryptLogin包就好啦：

'''登录'''def login(self, username, password):    lg = login.Login()    infos_return, session = lg.icourse163(username, password)    return infos_return, session

接着，我们简单讲解一下如何下载对应课程里的资料。首先，我们需要获得课程相关的基本资料，随便点开个课程主页就可以发现直接在返回的页面里就有：

提取我们需要的课程信息的代码实现如下：

# 从课程主页面获取信息url = url.replace('learn/', 'course/')response = self.session.get(url)term_id = re.findall(r'termId : "(\d+)"', response.text)[0]course_name = ' - '.join(re.findall(r'name:"(.+)"', response.text))course_name = self.filterBadCharacter(course_name)course_id = re.findall(r'https?://www.icourse163.org/(course|learn)/\w+-(\d+)', url)[0]print(f'从课程主页面获取的信息如下:\n\t[课程名]: {course_name}, [课程ID]: {course_name}, [TID]: {term_id}')

接着利用这些信息来爬取对应的资源列表：

# 获取资源列表resource_list = []data = {    'tid': term_id,    'mob-token': self.infos_return['results']['mob-token'],}response = self.session.post('https://www.icourse163.org/mob/course/courseLearn/v1', data=data)course_info = response.json()file_types = [1, 3, 4]for chapter_num, chapter in enumerate(course_info.get('results', {}).get('termDto', {}).get('chapters', [])):    for lesson_num, lesson in enumerate(chapter.get('lessons', [])) if chapter.get('lessons') is not None else []:        for unit_num, unit in enumerate(lesson.get('units', [])):            if unit['contentType'] not in file_types: continue            savedir = course_name            self.checkdir(savedir)            for item in [self.filterBadCharacter(chapter['name']), self.filterBadCharacter(lesson['name']), self.filterBadCharacter(unit['name'])]:                savedir = os.path.join(savedir, item)                self.checkdir(savedir)            if unit['contentType'] == file_types[0]:                savename = self.filterBadCharacter(unit['name']) + '.mp4'                resource_list.append({                    'savedir': savedir,                    'savename': savename,                    'type': 'video',                    'contentId': unit['contentId'],                    'id': unit['id'],                })            elif unit['contentType'] == file_types[1]:                savename = self.filterBadCharacter(unit['name']) + '.pdf'                resource_list.append({                    'savedir': savedir,                    'savename': savename,                    'type': 'pdf',                    'contentId': unit['contentId'],                    'id': unit['id'],                })            elif unit['contentType'] == file_types[2]:                if unit.get('jsonContent'):                    json_content = eval(unit['jsonContent'])                    savename = self.filterBadCharacter(json_content['fileName'])                    resource_list.append({                        'savedir': savedir,                        'savename': savename,                        'type': 'rich_text',                        'jsonContent': json_content,                    })print(f'成功获得资源列表, 数量为{len(resource_list)}')

最后根据资源类型解析下载即可：

# 下载对应资源pbar = tqdm(resource_list)for resource in pbar:    pbar.set_description(f'downloading {resource["savename"]}')    # --下载视频    if resource['type'] == 'video':        data = {            'bizType': '1',            'mob-token': self.infos_return['results']['mob-token'],            'bizId': resource['id'],            'contentType': '1',        }        while True:            response = self.session.post('https://www.icourse163.org/mob/j/v1/mobileResourceRpcBean.getResourceToken.rpc', data=data)            if response.json()['results'] is not None: break            time.sleep(0.5 + random.random())        signature = response.json()['results']['videoSignDto']['signature']        data = {            'enVersion': '1',            'clientType': '2',            'mob-token': self.infos_return['results']['mob-token'],            'signature': signature,            'videoId': resource['contentId'],        }        response = self.session.post('https://vod.study.163.com/mob/api/v1/vod/videoByNative', data=data)        # ----下载视频        videos = response.json()['results']['videoInfo']['videos']        resolutions, video_url = [3, 2, 1], None        for resolution in resolutions:            for video in videos:                if video['quality'] == resolution:                    video_url = video["videoUrl"]                    break            if video_url is not None: break        if '.m3u8' in video_url:            self.m3u8download({                'download_url': video_url,                'savedir': resource['savedir'],                'savename': resource['savename'],            })        else:            self.defaultdownload({                'download_url': video_url,                'savedir': resource['savedir'],                'savename': resource['savename'],            })        # ----下载字幕        srt_info = response.json()['results']['videoInfo']['srtCaptions']        if srt_info:            for srt_item in srt_info:                srt_name = os.path.splitext(resource['savename'])[0] + '_' + srt_item['languageCode'] + '.srt'                srt_url = srt_item['url']                response = self.session.get(srt_url)                fp = open(os.path.join(resource['savedir'], srt_name), 'wb')                fp.write(response.content)                fp.close()    # --下载PDF    elif resource['type'] == 'pdf':        data = {            't': '3',            'cid': resource['contentId'],            'unitId': resource['id'],            'mob-token': self.infos_return['results']['mob-token'],        }        response = self.session.post('http://www.icourse163.org/mob/course/learn/v1', data=data)        pdf_url = response.json()['results']['learnInfo']['textOrigUrl']        self.defaultdownload({            'download_url': pdf_url,            'savedir': resource['savedir'],            'savename': resource['savename'],        })    # --下载富文本    elif resource['type'] == 'rich_text':        download_url = 'http://www.icourse163.org/mob/course/attachment.htm?' + urlencode(resource['jsonContent'])        self.defaultdownload({            'download_url': download_url,            'savedir': resource['savedir'],            'savename': resource['savename'],        })

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