feedparser vs. network errors - something remembers that net was down.

John Nagle nagle at animats.com
Thu Apr 7 13:10:46 EDT 2011

   I have an application which uses feedparser (Python 2.6, of course),
on a Linux laptop.  If the network connection is up at startup, it
works fine.  If the network connection is down, feedparser reports
a network error.  That's fine.

   However, if the network is down, including access to DNS,
when the application starts, but
comes up later, the program continues to report a network error.
So, somewhere in the stack, someone is probably caching something.

   My own code looks like this:

     def fetchitems(self) :       # fetch more items from feed source
         try :                    # try fetching
             now = time.time()    # timestamp
             # fetch from URL
             d = feedparser.parse(self.url,etag=self.etag,
             # if network failure
             if d is None or not hasattr(d,"status") :
                 raise IOError("of network or news source failure")
             if d.status == 304 :            # if no new items
                 self.logger.debug("Feed polled, no changes.")
                 return                      # nothing to do
             self.logger.debug("Read feed: %d entries, status %s" %
                         (len(d.entries), d.status))
             if d.status != 200 :           # if bad status
                 raise IOError("of connection error No. %d" %

The exception at: IOError("of network or news source failure")
is raised.

Looking in feedeparser.py, "parse" calls "_open_resource",
which, after much fooling around, builds a urllib2 request,
builds an "opener" via urllib2, and calls its "open" method.

So I'm not seeing any state that should persist from call
to call. What am I missing?

				John Nagle

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