How to filter queryset with custom function

Question

I have the following models and I am trying to apply some filtering.

Basically I have this player model that can have multiple Experiences, and I want to send on my query params xp that will receive a value in years, and my queryset should only retrieve the players with at least that amount of years of experience in total.

The calc_player_experience method reads throw the players experience and calculates de amount of experience the player has and returns true or false if it meets the xp received on the query params.

How do I apply a function to model.filter() ? is that a thing?

models.py

class Player(BaseModel):
    name = models.CharField(_("name"), max_length=255, blank=True)

class Experience(BaseModel):
    player = models.ForeignKey(
        "players.Player", on_delete=models.CASCADE
    )
    team = models.CharField(_("team"), max_length=255)
    start_date = models.DateField(_("start_date"), null=True, blank=True)
    end_date = models.DateField(_("end_date"), null=True, blank=True)

views.py

class PlayersViewSet(viewsets.ModelViewSet):
    serializer_class = PlayerSerializer
    queryset = Player.objects.all()
    

    def get_queryset(self):
        """Filters the players to retrieve only those not archived and approved"""
        queryset = Player.objects.filter(is_approved=True, is_active=True)
        return apply_filters(self, queryset)

def apply_filters(obj, queryset):
    """Apply filters to given queryset"""

    xp = dict(obj.request.GET).get("xp", [])
    if xp:
        queryset = queryset.filter(lambda player: obj.calc_player_experience(player,xp[0])) 
        

Answer 1

In your views.py you need to return the queryset from the apply_filters function. Make sure you have a queryset returned even if it is empty.

def apply_filters(obj, queryset):
    """Apply filters to given queryset"""

    xp = dict(obj.request.GET).get("xp", [])
    if xp:
        queryset = queryset.filter(lambda player: obj.calc_player_experience(player,xp[0])) 
    return queryset