Question

I have an issue, where a function returns a number. When I then try to assemble a URL that includes that number I am met with failure.

Specifically the error I get is

TypeError: cannot concatenate ‘str’ and ‘NoneType’ objects

Not sure where to go from here.

Here is the relevant piece of code:

# Get the raw ID number of the current configuration
configurationID = generate_configurationID()

# Update config name at in Cloud
updateConfigLog = open(logBase+'change_config_name_log.xml', 'w')
# Redirect stdout to file
sys.stdout = updateConfigLog
rest.rest(('put', baseURL+'configurations/'+configurationID+'?name=this_is_a_test_', user, token))
sys.stdout = sys.__stdout__

It works perfectly if I manually type the following into rest.rest()

rest.rest(('put', http://myurl.com/configurations/123456?name=this_is_a_test_, myusername, mypassword))

I have tried str(configurationID) and it spits back a number, but I no longer get the rest of the URL…

Ideas? Help?

OK… In an attempt to show my baseURL and my configurationID here is what I did.

print 'baseURL: '+baseURL
print 'configurationID: '+configurationID

and here is what I got back

it-tone:trunk USER$ ./skynet.py fresh
baseURL: https://myurl.com/
369596
Traceback (most recent call last):
  File "./skynet.py", line 173, in <module>
    main()
  File "./skynet.py", line 30, in main
    fresh()
  File "./skynet.py", line 162, in fresh
    updateConfiguration()
  File "./skynet.py", line 78, in updateConfiguration
    print 'configurationID: '+configurationID
TypeError: cannot concatenate 'str' and 'NoneType' objects
it-tone:trunk USER$ 

What is interesting to me is that the 369596 is the config ID, but like before it seems to clobber everything called up around it.

As kindall pointed out below, my generate_configurationID was not returning the value, but rather it was printing it.

# from generate_configurationID
def generate_configurationID():
  dom = parse(logBase+'provision_template_log.xml')
  name = dom.getElementsByTagName('id')
  p = name[0].firstChild.nodeValue
  print p
  return p

Answer 1

Your configurationID is None. This likely means that generate_configurationID() is not returning a value. There is no way in Python for a variable name to “lose” its value. The only way, in the code you posted, for configurationID to be None is for generate_configurationID() to return None which is what will happen if you don’t explicitly return any value.

“But it prints the configurationID right on the screen!” you may object. Sure, but that’s probably in generate_configurationID() where you are printing it to make sure it’s right but forgetting to return it.

You may prove me wrong by posting generate_configurationID() in its entirety, and I will admit that your program is magic.