Django: Model limit_choices_to={'user': user}

Question

I went to all the documentation, also I went to the IRC channel (BTW a great community) and they told me that is not possible to create a model and limit choices in a field where the 'current user' is in a ForeignKey. I will try to explain this with an example:

class Project(models.Model):
  name = models.CharField(max_length=100)
  employees = models.ManyToManyField(Profile, limit_choices_to={'active': '1'})

class TimeWorked(models.Model):
  project = models.ForeignKey(Project, limit_choices_to={'user': user})
  hours = models.PositiveIntegerField()

Of course that code doesn't work because there is no 'user' object, but that was my idea and I was trying to send the object 'user' to the model to just limit the choices where the current user has projects, I don't want to see projects where I'm not in.

Thank you very much if you can help me or give me any advice, I don't want to you write all the app, just a tip how to deal with that. I have 2 days with this in my head and I can't figure it out :(

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UPDATE: The solution is here: http://collingrady.wordpress.com/2008/07/24/useful-form-tricks-in-django/ sending 'request.user' to a model.

Thanks to everybody who helped me.

Answer 1

Hmmm, I don't fully understand your question. But if you can't do it when you declare the model maybe you can achieve the same thing with overriding methods of the class of objects where you "send" the user object, maybe start with the constructor.

Answer 2

Model itself doesn't know anything about current user but you can give this user in a view to the form which operates models objects (and in form reset choices for necessary field).

If you need this on admin site - you can try raw_id_admin along with django-granular-permissions (http://code.google.com/p/django-granular-permissions/ but I couldn't rapidly get it working on my django but it seems to be fresh enough for 1.0 so...).

At last, if you heavily need a selectbox in admin - then you'll need to hack django.contrib.admin itself.

Answer 3

I'm not sure that I fully understand exactly what you want to do, but I think that there's a good chance that you'll get at least part the way there using a custom Manager. In particular, don't try to define your models with restrictions to the current user, but create a manager that only returns objects that match the current user.

Answer 4

Use threadlocals if you want to get current user that edits this model. Threadlocals middleware puts current user into process-wide variable. Take this middleware

from threading import local

_thread_locals = local()
def get_current_user():
    return getattr(getattr(_thread_locals, 'user', None),'id',None)

class ThreadLocals(object):
    """Middleware that gets various objects from the
    request object and saves them in thread local storage."""
    def process_request(self, request):
        _thread_locals.user = getattr(request, 'user', None)

Check the documentation on how to use middleware classes. Then anywhere in code you can call

user = threadlocals.get_current_user

Answer 5

Here is the CookBook Threadlocals And User