[Tutor] open a webpage which may be unavailable

[pileux systeme]

Hello,
   
  I am trying to retrieve data from several webpages. My problem is the following: after a random number of requests, the page I'm trying to open is unavailable (and I get an IOError). Note that the page may become available if I try again after some time. Since I have thousands pages to explore, I'd like to be able to continue the program in spite of this error.
  I've thought of trying to raise an exception such as:
  try:
    usock = urllib.urlopen('http:// <etc>')
  except:
  < something >
  else:
    usock = urllib.urlopen('http:// <etc>')
   
  However, this doesn't work because the page can become unavailable between the time when I run the 'try' and the 'else'. [for instance, assume that my internet connection stops for a couple seconds every random amount of time].
   
  Would anyone know how to solve this problem?
   
  [Another way to look at it is as follows: I'd like to be able to check whether the page is available AND copy it if it is AT THE SAME TIME]
   
  Thanks a lot for your answer,
   
  N.
   
   
   
   

       
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