What does the Django “expected string or buffer” error indicate?

Question

I've been stuck with this error for quite a while now and I just can't figure out what it means. It occurs when I try to save an object to my mysql database. Any ideas?

Thanks for the help!

Answer 1

This probably means that Python is trying to execute code which is expecting a certain datatype (bool, string, int, etc.), but an other, incorrect, datatype is provided.

Answer 2

Just ran into the same problem and resolved it. I instantiated a form like this:

data = {'date' : datetime.now} #this is the problem
form = MyForm(data)

That form was saved later on and django tried to set 'date' in the model. But datetime.now refers to a function rather than a date, obviously. What I wanted to do was datetime.now()

Maybe this helps anybody running into this in future.

Answer 3

In my case it was appears when I use "time" library to convert date string to datetime object. I just use "datetime.strptime" instead of "time.strptime"and problem vanished.

Answer 4

'expiration' is this field

expiration = models.DateTimeField(default=7)

And code with error was this one:

ex = timedelta(minutes=expiration)                      
authobj, created = cls.objects.update_or_create(                         
    operator=operator,                                                   
    defaults={'transport':transport,'token':cls.generate_key(40),'expiration':ex}
)                                                                        

And it was solved by setting it like this (instead of timedelta, a date)

ex = datetime.now() + timedelta(minutes=expiration)                      
authobj, created = cls.objects.update_or_create(                         
    operator=operator,                                                   
    defaults={'transport':transport,'token':cls.generate_key(40),'expiration':ex}
)                                                                        

Answer 5

The datetime validator in django is in the file:

/path/to/project/venv/lib/python2.7/site-packages/django/utils/dateparse.py

or in the site-packages of your current python interpreter.
Have a look there to see the regular expressions. In my case, the way to solve it was:

ended=datetime.fromtimestamp(time.time())
other=datetime.fromtimestamp(time.time())

# in the model:
ended = models.DateTimeField(blank=True, null=True) # or
other = models.DateTimeField(auto_now_add=False, blank=True)

both working.

Answer 6

str(yourvar)

Ou can convert sting your variables.