Django ModelForm field queryset based on another field - django

Question

Consider my models.py,
PowerPolicy:
class PowerPolicy(models.Model):
name = models.CharField(max_length=15)
...
Group:
class Group(models.Model):
name = models.CharField(max_length=15)
#But then, we also have:
power_policies = models.ManytoManyField(PowerPolicy)
Player:
class Player(models.Model):
name = models.CharField(max_length=15)
group = models.ForeignKey(Group, on_delete=models.CASCADE)
...
And then another model called,
UsePower:
class UserPower(models.Model):
player = models.ForeignKey(Player, on_delete=models.CASCADE)
power_policy = models.ForeignKey(PowerPolicy, on_delete=models.CASCADE)
...
But! Here's the catch: I want to make it so that my superuser (Note that my superuser isn't a player, he's simply a superuser) can only create a UsePower object of the Powers specified in the Player's Group. Now, I do know that I have to create a custom form and override the queryset of the power_policy field that returns, my the custom queryset according to my needs through a function.
- Here's what it would look something like:
class UsePowerForm(forms.ModelForm):
def __init__(self, *args, **kwargs):
super(UsePowerForm, self).__init__(*args, **kwargs)
def MyCustomFunctionThatReturnsTheQuerySet():
This function returns the Power policies that are allowed to the player in
their player Group. The only problem is,
Our little function here doesn't know how to get the player chosen.
could you help
return TheQuerySet
self.fields['power_policy'].queryset = MyCustomFunctionThatReturnsTheQuerySet()
And then use it on the Admin Site, by doing this:
class UsePowerAdmin(admin.ModelAdmin):
form = UsePowerForm
admin.site.register(UsePower, UsePowerForm)
I really hope this makes sense, and you guys could help me out.
Thank you for your time reading this, I honestly do appreciate it.
EDIT: Using form cleaning, or verifying during save, is not an option for me :(

Answer 1

You can get the player when the form is being initialized:
class UserPowerForm(forms.ModelForm):
def __init__(self, *args, **kwargs):
super(UsePowerForm, self).__init__(*args, **kwargs)
player = Player.objects.get(id=self.initial['player'])
###from here you can use player to get the power policies and put into list
self.fields['power_policy'] = forms.ChoiceField(choices=power_policy_list)
class Meta:
model = UserPower
fields = ['player', 'power_policy']