unbound method must be called with instance as first argument - django

Question

I'm working with django and i'm getting this error: "unbound method create() must be called with SocialUrl instance as first argument (got nothing instead)". I've read several answers to the same problem here but i'm not sure they are doing the same thing wrong as i am.
Here is the Model containing the method i'm trying to call:
from django.db import models
class SocialUrl(models.Model):
code = models.CharField(max_length=30)
def create():
socialUrl = SocialUrl(code = generateCode())
socialUrl.save()
return socialUrl
def __unicode__(self):
return self.code
and here is the method trying to call SocialUrl.create():
from django.shortcuts import render
from django.template import RequestContext
from .general import generateCode
from .models import SocialUrl
def test(request):
socialUrl = SocialUrl.create()
#print(SocialUrl.objects.all())
return render(request, 'test.html', RequestContext(request, {"title": socialUrl.code}))
Here is the stacktrace:
Environment:
Request Method: GET
Request URL: http://127.0.0.1:8000/su/asdadsf
Django Version: 1.6.2
Python Version: 2.7.6
Installed Applications:
('django.contrib.admin',
'django.contrib.auth',
'django.contrib.contenttypes',
'django.contrib.sessions',
'django.contrib.messages',
'django.contrib.staticfiles',
'SocialUrl')
Installed Middleware:
('django.contrib.sessions.middleware.SessionMiddleware',
'django.middleware.common.CommonMiddleware',
'django.middleware.csrf.CsrfViewMiddleware',
'django.contrib.auth.middleware.AuthenticationMiddleware',
'django.contrib.messages.middleware.MessageMiddleware',
'django.middleware.clickjacking.XFrameOptionsMiddleware')
Traceback:
File "C:\Users\Sverker\.virtualenvs\coomba\lib\site- packages\django\core\handlers\base.py" in get_response
114. response = wrapped_callback(request, *callback_args, **callback_kwargs)
File "C:\Users\Sverker\Dropbox\Coomba\SbrgCoomba\SocialUrl\views.py" in test
8. socialUrl = SocialUrl.create()
Exception Type: TypeError at /su/asdadsf
Exception Value: unbound method create() must be called with SocialUrl instance as first argument (got nothing instead)
Help would be appreciated :)

Answer 1

You need to instantiate the class before calling a method on the class. Change your view to:
from django.shortcuts import render
from django.template import RequestContext
from .general import generateCode
from .models import SocialUrl
def test(request):
socialUrl = SocialUrl()
socialUrl.create()
#print(SocialUrl.objects.all())
return render(request, 'test.html', RequestContext(request, {"title": socialUrl.code}))
Notice how you instantiate the object first (socialUrl = SocialUrl()) then you run create on the object you've instantiated. (socialUrl.create()).
However, I'm not sure your create method is going to work as you intend. What are you trying to accomplish with the create method?
EDIT to address comments:
I'm not familiar with Java static methods, but I think the standard way to what you want to do is as follows:
First, define your model as you've done. Note that I removed the create method.
from django.db import models
class SocialUrl(models.Model):
code = models.CharField(max_length=30)
def __unicode__(self):
return self.code
Then, in your views, instantiate a model and populate it with the attributes you want.
from django.shortcuts import render
from django.template import RequestContext
from .general import generateCode
from .models import SocialUrl
def test(request):
my_code = generateCode()
socialUrl = SocialUrl()
socialUrl.code = my_code # Setting code attribute to the result of your generateCode function
socialUrl.save() # Saves instance of SocialUrl to database.
return render(request, 'test.html', RequestContext(request, {"title": socialUrl.code}))