dropbox.py 文件源码

def download_file_chunk(url, buf):
    opener = urllib2.build_opener()
    opener.addheaders = [('User-Agent', "DropboxLinuxDownloader/1.6.2")]
    sock = opener.open(url)

    size = int(sock.info()['content-length'])
    bufsize = max(size / 200, 4096)
    progress = 0

    with closing(sock) as f:
        yield (0, True)
        while True:
            try:
                chunk = f.read(bufsize)
                progress += len(chunk)
                buf.write(chunk)
                yield (float(progress)/size, True)
                if progress == size:
                    break
            except OSError as e:
                if hasattr(e, 'errno') and e.errno == errno.EAGAIN:
                    # nothing left to read
                    yield (float(progress)/size, False)
                else:
                    raise