In article <20165c85-4cc3-4b79-943b-82443e4a9...@w7g2000vbw.googlegroups.com>, Jean Dubois <jeandubois...@gmail.com> wrote:
> But, really, > > once you've done all that (and it's worth doing as an exercise), rewrite > > your code to use urllib2 or requests. It'll be a lot easier. > > Could you show me how to code the example in metacode below wuth the > use of urllib2? > #!/usr/bin/env python > import urllib2 > if check whether url exists succeed: > print 'url exists' > else: > print 'url does not exist' There are two basic ways Python function return status information. Either they return something which indicates failure (such as None), or they raise an exception. In this case, what you want is urlopen(), which is documented at http://docs.python.org/2/library/urllib2.html. The key piece of information is a couple of paragraphs down, where it says, "Raises URLError on errors". It's not obvious from reading that whether URLError is a built-in or not, but that's easy enough to figure out: >>> URLError Traceback (most recent call last): File "<stdin>", line 1, in <module> NameError: name 'URLError' is not defined >>> import urllib2 >>> urllib2.URLError <class 'urllib2.URLError'> So, that means you want something like: #!/usr/bin/env python import urllib2 url = "http://whatever...."; try: urllib2.urlopen(url) print "url exists" except urllib2.URLError: print "url does not exist"
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