django custom manager with filter parameter - django

Question

I would like to add a custom manager which can be called from a template, but does not affect the entire model (e.g. admin views) and which listens to a parameter set in the request (user_profile).
The following is what I have so far:
models.py:
class CurrentQuerySet(models.query.QuerySet):
def current(self):
return self.filter(id=1) ## this simplified filter test works..
class CurrentManager(models.Manager):
use_for_related_fields = True
def get_query_set(self):
return CurrentQuerySet(self.model)
def current(self, *args, **kwargs):
return self.get_query_set().current(*args, **kwargs)
For model B is defined:
objects = CurrentManager()
The template calls:
{% for b in a.b_set.current %}
But as soon as I try to pass a parameter to that filter (in this case a date stored on the user-profile) the method does not return any results.
e.g.:
models.py
class CurrentQuerySet(models.query.QuerySet):
def current(self,my_date):
return self.filter(valid_from__lte=my_date)
showA.html
{% for b in a.b_set.current(request.user.get_profile.my_date) %}
Instead of passing the parameter from the template, I have also tried to set this in the view.py
#login_required
def showA(request,a_id):
my_date = request.user.get_profile().my_date
a = A.objects.get(id=a_id)
t = loader.get_template('myapp/showA.html')
c = RequestContext(request,{'a':a,'my_date':my_date,})
return HttpResponse(t.render(c))
Which part am I missing (or misunderstanding) here?
Thanks
R
Edit
Here the models. As mentioned, in this example it's a simple 1:n relationship, but can also be m:n in other cases.
class A(models.Model):
#objects = CurrentManager()
a = models.CharField(max_length=200)
description = models.TextField(null=True,blank=True)
valid_from = models.DateField('valid from')
valid_to = models.DateField('valid to',null=True,blank=True)
def __unicode__(self):
return self.a
class B(models.Model):
#objects = models.Manager()
objects = CurrentManager()
a = models.ForeignKey(A)
b = models.CharField(max_length=200)
screenshot = models.ManyToManyField("Screenshot",through="ScreenshotToB")
description = models.TextField(null=True,blank=True)
valid_from = models.DateField('valid from')
valid_to = models.DateField('valid to',null=True,blank=True)
def __unicode__(self):
return self.b
Edit-2
The accepted answer works for at least one relationship.
In case of a more nested data model, this method seems not to deliver the expected results:
models.py
class C(models.Model):
objects = CurrentManager()
b = models.ForeignKey(A)
c = models.CharField(max_length=200)
description = models.TextField(null=True,blank=True)
valid_from = models.DateField('valid from')
valid_to = models.DateField('valid to',null=True,blank=True)
def __unicode__(self):
return self.c
views.py
#login_required
def showA(request,a_id):
a = A.objects.get(id=a_id)
my_date = request.user.get_profile().my_date
b_objects = a.b_set.current(my_date)
c_objects = b_objects.c_set.current(my_date)
t = loader.get_template('controltool2/showA.html')
c = RequestContext(request,{'a':a,'b_objects':b_objects,'c_objects':c_objects,})
return HttpResponse(t.render(c))
This returns the error: 'QuerySet' object has no attribute 'c_set'.

Answer 1

I'd simplify it:
class CurrentManager(models.Manager):
def current(self, my_date):
return super(CurrentManager, self).get_query_set().filter(valid_from__lte=my_date)
and then use it like this:
a = A.objects.get(id=a_id)
my_date = request.user.get_profile().my_date
b_objects = a.b_set.objects.current(my_date)
and then just pass a to the template as the filtered objects accessing them using this:
{% for b in b_objects %}
Hope this helps!
Edit (by requestor):
I had to adjust it as follows to get it working:
a = A.objects.get(id=a_id)
my_date = request.user.get_profile().my_date
b_objects = a.b_set.current(my_date)
This threw an error: "'RelatedManager' object has no attribute 'objects'"
a.b_set.objects.current(my_date)