Python m3u8文件下载，去重，文件管理，文件合并，文件去重，判断文件是否存在，下载文件是否存在等

在Python中，对于M3U8格式的直播流文件，通常我们需要使用第三方库如`pydash`, `requests`和`m3u8`来下载、管理和处理。这里有一个简化版的例子，展示如何进行文件下载、去重、合并、判断文件是否存在及下载文件是否存在等功能：

首先安装必要的库：

pip install requests pydash

然后创建一个名为`M3U8Manager`的类：

import requests
import pydash
from m3u8 import M3U8

class M3U8Manager:
    def __init__(self, m3u8_url, download_dir='downloads'):
        self.m3u8_url = m3u8_url
        self.download_dir = download_dir
        self.cache = {}
        
    def download_segment(self, segment_url):
        filename = segment_url.split('/')[-1]
        local_path = os.path.join(self.download_dir, filename)
        if not os.path.isfile(local_path) or self.is_duplicate(local_path):
            response = requests.get(segment_url, stream=True)
            if response.status_code == 200:
                with open(local_path, 'wb') as f:
                    for chunk in response.iter_content(chunk_size=1024):
                        f.write(chunk)
                print(f'Successfully downloaded: {local_path}')
            else:
                print(f'Download failed with status code: {response.status_code}')
    
    def merge_segments(self, output_filename='merged.mp4'):
        segments = [segment for segment in self.get_all_segments() if segment.is_video]
        with open(output_filename, 'wb') as merged:
            for segment in segments:
                with open(segment.url, 'rb') as seg_f:
                    merged.write(seg_f.read())
    
    def get_all_segments(self):
        m3u8_obj = M3U8(self.m3u8_url)
        return m3u8_obj.segments
    
    def is_duplicate(self, local_path):
        if local_path in self.cache:
            return True
        else:
            self.cache[local_path] = True
            return False
    
    # 判断文件是否存在
    def is_file_exist(self, local_path):
        return os.path.exists(local_path)

    # 下载文件是否存在
    def download_if_not_exists(self, segment_url):
        if not self.is_file_exist(self.get_local_path_from_url(segment_url)):
            self.download_segment(segment_url)

    def get_local_path_from_url(self, url):
        return url.split('/')[-1]

# 使用示例
manager = M3U8Manager('http://example.com/my_m3u8_file.m3u8')
# 下载所有视频段并合并
manager.merge_segments()

# 检查并下载不存在的文件
for segment in manager.get_all_segments():
    manager.download_if_not_exists(segment.url)

这个例子展示了基本的M3U8文件下载、去重（通过缓存防止重复下载）、合并和文件存在检查功能。注意实际使用中可能会遇到网络问题或其他异常情况，需要适当处理。