import tarfile
import requests

class PDownload(object):
    def __init__(self, url):
        self.url = url
        self.current = 0
        self.session = requests.Session()

    def tell(self):
        return self.current

    def read(self, blocksize):
        req = self.session.get(self.url, headers={'Range': 'bytes=%s-%s'%(self.current, self.current+blocksize-1)})
        self.current += blocksize
        return req.content

    def seek(self, offset):
        self.current = offset

if __name__ == '__main__':
    obj = PDownload('https://dimonb.com/.torrents/qqq.tar')
    tar = tarfile.TarFile(fileobj=obj)
    print tar.getmembers()