How can I apply custom filters in views for django rest framework serialiser?

Question

I have the following three model definitions

class Program(models.Model):

    title = models.CharField(max_length=200, null=True, blank=True)
    assigned_by = models.ForeignKey('physio.Physio', null=True, blank=True)
    assigned_to = models.ManyToManyField('patient.Patient')
    start_date = models.DateTimeField(null=True, blank=True)
    end_date = models.DateTimeField(null=True, blank=True)
    duration = models.CharField(max_length=200, null=True, blank=True)
    description = models.CharField(max_length=200, null=True, blank=True)
    exercises = models.ManyToManyField(
        'exercise.Exercise')

Here is the serialiser

class ProgramSerializer(serializers.HyperlinkedModelSerializer):

    class Meta:
        model = Program
        fields = (
            'title', 'assigned_by', 'start_date', 'end_date', 'duration', 'description', 'exercises'
        )

Following is the views :

class ProgramViewSet(viewsets.ModelViewSet):

    """
    API endpoint that allows users to be viewed or edited.
    """
    queryset = Program.objects.all()
    serializer_class = ProgramSerializer

I want to Get all programs assigned by a particular physio to a patient. How should the views be altered?

The URL can be - /programs/physio/:physioID/patient/:patientID

I have used routers for the generic list and detail views.

Answer 1

You can implement .get_queryset() method of ProgramViewSet

def get_queryset(self):

    physio = Physio.objects.get(id=self.kwargs['physioID'])
    patient = Patient.objects.get(id=self.kwargs['patientID'])

    return Purchase.objects.filter(assigned_by=physio,
                                   assigned_to=patient)

As described in the documentation .