import os
from urllib.request import urlopen
from tqdm import tqdm
import requests
import sys
from threading import Thread,Lock
lock = Lock()
def download(url,filename=None):
    file_size = int(requests.head(url).headers['Content-Length'])
    if not filename:
        filename = url.split('/')[-1]
    if os.path.exists(filename):
        first_byte = os.path.getsize(filename)
        print('断点续传中。。。')
    else:
        first_byte = 0
    header = {'Range': 'bytes=%s-%s' % (first_byte, file_size)}
    pbar = tqdm(total=file_size,initial=first_byte,unit='B',unit_scale=True,desc=url.split('/')[-1],mininterval=0.5)
    result = requests.get(url,headers = header,stream=True)
    with open(filename,'ab') as f:
        for chunk in result.iter_content(chunk_size=1024):
            f.write(chunk)
            pbar.update(1024)
    pbar.close()
    return file_size
if __name__ == '__main__':
    download('http://huo.hongjiaozuida.com/20200606/5381_8ab40c11/少年间谍第一季-08.mp4')