在python3中，urllib2被替换为urllib.requeset，因此头文件中添加

import urllib.request as urllib2
def getRemoteFileSize(url, proxy=None):
 """ 通过content-length头获取远程文件大小
  url - 目标文件URL
  proxy - 代理 """
 opener = urllib2.build_opener()
 if proxy:
  if url.lower().startswith('https://'):
   opener.add_handler(urllib2.ProxyHandler({'https' : proxy}))
  else:
   opener.add_handler(urllib2.ProxyHandler({'http' : proxy}))
 try:
  request = urllib2.Request(url)
  request.get_method = lambda: 'HEAD'
  response = opener.open(request)
  response.read()
 except Exception:
  return 0
 else:
  print(response.headers)
  fileSize = dict(response.headers).get('content-length', 0)
  return int(fileSize)

使用上段代码发现输出为0，考虑应该是没查询到content-length字段，打印response.headers字段后，发现content-length字段应改为Content-Length，改后正常

在这里插入图片描述

def getRemoteFileSize(url, proxy=None):
 """ 通过content-length头获取远程文件大小
  url - 目标文件URL
  proxy - 代理 """
 opener = urllib2.build_opener()
 if proxy:
  if url.lower().startswith('https://'):
   opener.add_handler(urllib2.ProxyHandler({'https' : proxy}))
  else:
   opener.add_handler(urllib2.ProxyHandler({'http' : proxy}))
 try:
  request = urllib2.Request(url)
  request.get_method = lambda: 'HEAD'
  response = opener.open(request)
  response.read()
 except Exception:
  return 0
 else:
  print(response.headers)
  fileSize = dict(response.headers).get('Content-Length', 0)
  return int(fileSize)

总结