UnboundLocalError: local variable 'XXXX' referenced before assignment

[theChips]

I have no problem running my app on localhost, but when I deploy it I
receive this error:


2011-08-24 16:55:57.464 Traceback (most recent call last):
E 2011-08-24 16:55:57.464 File "/base/data/home/apps/
s~brittanybermantweets/1.352785960472444569/web/application.py", line
237, in process
E 2011-08-24 16:55:57.464 return self.handle()
E 2011-08-24 16:55:57.464 File "/base/data/home/apps/
s~brittanybermantweets/1.352785960472444569/web/application.py", line
228, in handle
E 2011-08-24 16:55:57.464 return self._delegate(fn, self.fvars, args)
E 2011-08-24 16:55:57.464 File "/base/data/home/apps/
s~brittanybermantweets/1.352785960472444569/web/application.py", line
409, in _delegate
E 2011-08-24 16:55:57.464 return handle_class(cls)
E 2011-08-24 16:55:57.464 File "/base/data/home/apps/
s~brittanybermantweets/1.352785960472444569/web/application.py", line
385, in handle_class
E 2011-08-24 16:55:57.464 return tocall(*args)
E 2011-08-24 16:55:57.464 File "/base/data/home/apps/
s~brittanybermantweets/1.352785960472444569/brittanyberman.py", line
18, in GET
E 2011-08-24 16:55:57.464 tweets = brittanytweets.getTweets()
E 2011-08-24 16:55:57.464 File "/base/data/home/apps/
s~brittanybermantweets/1.352785960472444569/brittanytweets.py", line
16, in getTweets
E 2011-08-24 16:55:57.464 tweets = json.loads(rawtweets)
E 2011-08-24 16:55:57.464 UnboundLocalError: local variable
'rawtweets' referenced before assignment


To make matters more confusing, it worked fine when I deployed it last
night.

Here is the python in question:

import urllib2
import simplejson as json

url = "http://api.twitter.com/1/statuses/user_timeline.json?
screen_name=brittanyberman"


def getTweets():
try:
rawtweets = urllib2.urlopen(url).read()
except urllib2.HTTPError, e:
print "HTTP error: %d" % e.code
except urllib2.URLError, e:
print "Network error: %s" % e.reason.args[1]

alltweets=[]
tweets = json.loads(rawtweets)

for i in range(12):
alltweets.append(tweets[i]['text'])

#strip out the 'u' char
for i in range(len(alltweets)):
alltweets[i]=str(alltweets[i])

return alltweets


The script runs fine on a local shell. Any idea what's wrong?

Thanks!

[Robert Schuppenies]

Looks to me like your "urllib2.urlopen(url).read()" call fails. UnboundLocalError means that 'rawtweets' wasn't assigned, and it is only assigned if this call returns successfully.

Here is another example for this:

"""

>>> def raise_error():

...   raise ValueError("i'm an error")

... 

>>> def look_ma_referenced_before_assignment():

...   try:

...     x = raise_error()

...   except ValueError, e:

...     print e

...   print x

... 

>>> look_ma_referenced_before_assignment()

i'm an error

Traceback (most recent call last):

  File "<stdin>", line 1, in <module>

  File "<stdin>", line 6, in look_ma_referenced_before_assignment

UnboundLocalError: local variable 'x' referenced before assignment

"""

So I would check if "urllib2.urlopen(url).read()" actually works. For example:

- check if an error message is printed

- catch all errors, not just urllib2 errors.

cheers,

robert

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