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Read from a URL resource with error trapping
Exceptions example from a Well House Consultants training course
More on Exceptions [link]
Source code: grabot.py Module: Y109
""" urllib allows you to open a remote URL and handle the data as if it was a file, since the object returned from a urllib.urlopen shares many method names with file handling. However, you're strongly recommended to trap exceptions as we have done in this example to handle cases where the remote server is not available or the file you're requesting from there is no longer available. """ import urllib try: datasource = urllib.urlopen("http://www.wellho.net/robots.txt") aok = 1 except: print "Can't reach resource" aok = 0 if aok: while 1: line = datasource.readline() if line == "": break # Python's str.partition method splits a string into three at a given seperator # - bit before # - separator # - bit after # If the separator does not match, everything is placed in the "bit before" posn # ** really useful for stripping comments! before, at, after = line.partition("#") info = before.strip() if info: print info """ Sample results wizard:pyoo graham$ python grabot.py User-agent: * Disallow: /cgi-bin/ Disallow: /net/unique.html Disallow: /happens/ Disallow: /resources/mywellho.html Disallow: /net/search.php4 Disallow: /demo/poc01.php?item Disallow: /illust/ Disallow: /net/recents.html Disallow: /net// Disallow: /resources// Disallow: /short/ Disallow: /share/e107 Disallow: /share/skin Disallow: /share/zboard Disallow: /share/component Disallow: /share/bbs Disallow: /share/admin Disallow: /share/modules Disallow: /resources/maps.htm Disallow: /net/maps.htm Disallow: /wiltshire/index.php4 Disallow: /share/index.php4 Disallow: /overview Disallow: /demo/pflog User-agent: TurnitinBot Disallow: / wizard:pyoo graham$ """ Learn about this subject
This module and example are covered on the following public courses:
* Learning to program in Python * Python Programming * Intermediate Python Also available on on site courses for larger groups Books covering this topic
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