在python中的URL验证和缩短

我写了一个简单的URL验证和缩写在python中，我怎么能从网站的url保存图像的小尺寸？并认识到它不是像.rar或.zip这样的“文件”？我apreciate如果编辑我的代码有更好的表现..在python中的URL验证和缩短

from urllib2 import Request, urlopen, URLError 
from urlparse import urlparse 
import string 
import random 

url = raw_input('plZ enter the url: ').lower()  #get input and convert to lowercase 
while True: 
    if url[0:7] == 'http://' or url[0:8] == 'https://' or url[0:6] =='ftp://':   #check the url protocol 
     try:          #try to open url 
      response = urlopen(url) 
      parsed_url = urlparse(url) 
      rand_url = ''.join(random.choice(string.ascii_uppercase + string.digits + string.ascii_lowercase) for x in range(6)) 
      print " The shortened url is: http://url.com/" + rand_url 
      print "\n Original URL is: "+url 
      exit() 
     except URLError, e:       #except the error by asking the address again 
      if hasattr(e, 'reason'): 
       print "URL is not valid or server is NOT responsive..plZ try again.." 
       url = raw_input('plZ enter the url: ').lower() 
      #print 'Reason: ', e.reason 
      elif hasattr(e, 'code'): 
       print 'The server couldn\'t fulfill the request.'  #message in case of server or connection error 
       print 'Error code: ', e.code 
    else: 
     print "\n protocol missing, using HTTP instead.. \n" 
     url = "http://"+url

来源

2012-08-16 Hojat Taheri

你想想图标或者说整个页面的图像，因为它是由歌剧院，Firefox或Chrome表明，他们显示了“快速拨号”？ – 2012-08-16 12:19:42

恰好像歌剧和火狐的形象。 – 2012-08-16 12:25:44

不要使用'lower（）'。网址是区分大小写的，原则上通常在实践中。 – alexis 2012-08-16 20:49:05