CODEWITHSUNDEEP
pythondjangodjango-rest-framework
Jekson
Jekson

Reputation: 3262

How to serialize generic relations in DRF?

I have an Administrator model associated with three other models through generic relationship.

A = 'Active'
    D = 'Disabled'
    status = (
        (A, 'Active'),
        (D, 'Disabled')
    )

    limit_choices = (models.Q(app_label='core', model='track') | models.Q(app_label='core',
                    model='company') | models.Q(app_label='core', model='member') )
    content_type = models.ForeignKey(ContentType, limit_choices_to=limit_choices, on_delete=models.CASCADE)
    object_id = models.PositiveIntegerField()
    content_object = GenericForeignKey('content_type', 'object_id')
    status = models.CharField(max_length=7, choices=status, default=D)

class Track(models.Model):
    name = models.CharField(max_length=70)



class Company(models.Model):
    partner_id = models.ForeignKey(Track, related_name='companies', on_delete=models.CASCADE)
    name = models.CharField(max_length=70)


class Member(models.Model):
    carrier_id = models.ForeignKey(Track,  on_delete=models.CASCADE)
    name = models.CharField(max_length=70)

For serialization, I use the sample code from the official documentation.

serializer.py

class AdministratorSerializer(serializers.RelatedField):

    class Meta:
        fields = ('id', 'status', )
        model = Administrator

    def to_representation(self, value):

        if isinstance(value, Track):
            return value.id
        elif isinstance(value, Member):
            return value.id
        elif isinstance(value, Company):
            return value.id
        raise Exception('Unexpected type of tagged object')

But I got an error

TypeError at /administrator/
__init__() takes exactly 1 argument (3 given)

Please help me to solve this task/

Upvotes: 1

Views: 1650

Answers (1)

JPG
JPG

Reputation: 88539

The DRF docs says, Create a generic serializer field (here, GenericField) and wire-up in your Serializer class (here, AdministratorSerializer ).

class GenericField(serializers.RelatedField):

    def to_representation(self, value):

        if isinstance(value, Track):
            return value.id
        elif isinstance(value, Member):
            return value.id
        elif isinstance(value, Company):
            return value.id
        raise Exception('Unexpected type of tagged object')


class AdministratorSerializer(serializers.ModelSerializer):
    generic_data = GenericField(source='content_object', read_only=True)

    class Meta:
        fields = ('id', 'status', 'generic_data')
        model = Administrator

Upvotes: 6

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