How to validate different data in the same serializer in DRF

[Syed Shamikh Shabbir]

Hi,
I need help with something

This is my current setup

I want to be able to create new contributor entities as well as relating the old entities using the same data all when sending the parent Campaign data.

I cannot use create method in serializers as I want all my logic to be reusable since I'll have multiple different ways of creating the same thing

models.py

```python

   class BaseModel(models.Model):

        created_at = models.DateTimeField(

            editable=False, auto_now_add=True, verbose_name=_("Created At")

        )

        updated_at = models.DateTimeField(

            editable=False, auto_now=True, verbose_name=_("Updated At")

        )

        class Meta:

            abstract = True

    class Contributor(BaseModel):

        name = models.CharField(max_length=128)

    class Contact(BaseModel):

        name = models.CharField(max_length=128)

        phone_number = models.CharField(max_length=128, blank=True, null=True)

    class CampaignContributor(models.Model):

        campaign = models.ForeignKey(Campaign, on_delete=models.CASCADE)

        contributor = models.ForeignKey(Contributor, on_delete=models.CASCADE)

        tags = ArrayField(

            models.CharField(max_length=255, blank=True, null=True), null=True

        )

    class Campaign(BaseModel):

        title = models.CharField(max_length=128)

        contributors = models.ManyToManyField(Contributor, through="CampaignContributor")

```

serializers.py

```python

    class ContactSerializer(serializers.ModelSerializer):

        class Meta:

            model = Contact

            fields = "__all__"

            depth = 1

    class ContributorSerializer(serializers.ModelSerializer):

        contacts = ContactSerializer(many=True)

        class Meta:

            model = Contributor

            fields = "__all__"

            depth = 1

    class CampaignContributorSerializer(serializers.ModelSerializer):

        contributor = ContributorSerializer()

        class Meta:

            model = CampaignContributor

            fields = "__all__"

    class CampaignSerializer(serializers.ModelSerializer)

        contributors = CampaignContributorSerializer(

            many=True, extra_excludes=["campaign"], source="campaigncontributor_set"

        )

        class Meta:

            model = Campaign

            fields = "__all__"

            depth = 1

```

views.py

```python

    class CampaignViewSet(viewsets.ModelViewSet):

        lookup_url_kwarg = "id"

        queryset = Campaign.objects.all()

        serializer_class = CampaignSerializer

        def create(self, request, *args, **kwargs):

            serializer = CampaignSerializer(request.data)

            serializer.is_valid(raise_exception=True)

            campaign = create_campaign(serializer.data)

            return Response(campaign)

```

services.py

```python

def create_campaign(validated_data):

    # handle model creation here

    return campaign

```

sample data I want to send

```json

{

  "title": "Test Campaign for SpringField",

  "contributors": [

    {"contributor": {"id": 1}}, // old contributor I want to be related to the newly created Campaign object

    {

      "contributor": {

        "name": "Homer Simpson",

        "contacts": [

          {

            "name": "Ned Flanders",

            "phoneNumber": "+123456789012"

          }

        ]

      },

      "tags": [

        "loopback",

        "regulator"

      ]

    }

  ]

}

```

What is the best way of doing this?