n00b confusion re: local variable referenced before assignment error

[Wells Oliver]

Writing a class which essentially spiders a site and saves the files
locally. On a URLError exception, it sleeps for a second and tries again (on
404 it just moves on). The relevant bit of code, including the offending
method:

class Handler(threading.Thread):
        def __init__(self, url):
                threading.Thread.__init__(self)
                self.url = url

        def save(self, uri, location):
                try:
                        handler = urllib2.urlopen(uri)
                except urllib2.HTTPError, e:
                        if e.code == 404:
                                return
                        else:
                                print "retrying %s (HTTPError)" % uri
                                time.sleep(1)
                                self.save(uri, location)
                except urllib2.URLError, e:
                        print "retrying %s" % uri
                        time.sleep(1)
                        self.save(uri, location)

                if not os.path.exists(os.path.dirname(location)):
                        os.makedirs(os.path.dirname(location))

                file = open(location, "w")
                file.write(handler.read())
                file.close()

...

But what I am seeing is that after a retry (on catching a URLError
exception), I see bunches of "UnboundLocalError: local variable 'handler'
referenced before assignment" errors on line 38, which is the
"file.write(handler.read())" line..

What gives?

-- 
Wells Oliver
wells at submute.net
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