新技能 get —— Python 断点续传下载文件

from urllib.request import urlretrieve
import sys
import os

prev_reported_download_percent = None

# 首先定义下载 hook，作为 urllib.request.urlretrive 的关键字参数
def download_hook(count, block_size, total_size):
""" 接口是写死的 """
global prev_reported_download_percent
percent = int(count*block_size*100/total_size)
if prev_reported_download_percent != percent:
if percent % 5 == 0:
sys.stdout.write('%s%%' % percent)
sys.stdout.flush()
else:
sys.stdout.write('.')
sys.stdout.flush()
prev_reported_download_percent = percent

def maybe_download(filename, force=False):
""" force 表示是否强制下载 """
if force or not os.path.exists(filename):
print('Attempting to download')
filename, _ = urlretrieve(url+filename, filename, reporthook=download_hook)
# url+filename：表示文件的 url 地址，
# filename 则为保存到本地时的文件名
print('\nDownload completed!')
# statinfo = os.stat(filename)
return filename

http://ufldl.stanford.edu/housenumbers/

train.tar.gz

test.tar.gz

url = 'http://ufldl.stanford.edu/housenumbers/'
train_filename = maybe_download('train.tar.gz')
test_filename = maybe_download('test.tar.gz')