Make a model field as required on the base of a condition in Django Models

Question

I'm working on a project with Python(3.6) and Django(2.0) in which I need to make a field in child model required on the base of a condition for a field in parent model class.

If the service is multiple then the routing and configuration fields will be required otherwise it's not necessary to be filled.

Here's my code from models.py

From models.py:

services = (
    ('Single', 'Single'),
    ('Multiple', 'Multiple'),
)


class DeploymentOnUserModel(models.Model):
    deployment_name = models.CharField(max_length=256, )
    credentials = models.TextField(blank=False)
    project_name = models.CharField(max_length=150, blank=False)
    project_id = models.CharField(max_length=150, blank=True)
    cluster_name = models.CharField(max_length=256, blank=False)
    zone_region = models.CharField(max_length=150, blank=False)
    services = models.CharField(max_length=150, choices=services)
    configuration = models.TextField(blank=True)
    routing = models.TextField(blank=True)

    def save(self, **kwargs):
        if self.services == 'Multiple' and not self.routing and not self.configuration:
            raise ValidationError("You must have to provide routing for multiple services deployment.")
        super().save(**kwargs)

From serializers.py:

class DeploymentOnUserSerializer(serializers.ModelSerializer):
    class Meta:
        model = DeploymentOnUserModel
        fields = '__all__'

From apiview.py:

class DeploymentsList(generics.ListCreateAPIView):
    queryset = DeploymentOnUserModel.objects.all()
    serializer_class = DeploymentOnUserSerializer

    def get(self, request, *args, **kwargs):
        return self.list(request, *args, **kwargs)

    def post(self, request, *args, **kwargs):
        serializer = DeploymentOnUserSerializer(data=self.request.data)
        validation = serializer.is_valid()
        if validation is True:
            perform_deployment(self.request.data)
            self.create(request=self.request)
        else:
            return Response('You haven\' passed the correct data ')
        return Response(serializer.data)

Post payload:

{
  "deployment_name": "first_deployment",
  "credentials":{
  "type": "service_account",
  "project_id": "project_id",
  "private_key_id": "private_key_id",
  "private_key": "-----BEGIN PRIVATE KEY",
  "client_email": "client_email",
  "client_id": "client_id",
  "auth_uri": "https://accounts.google.com/o/oauth2/auth",
  "token_uri": "https://accounts.google.com/o/oauth2/token",
  "auth_provider_x509_cert_url": "https://www.googleapis.com/oauth2/v1/certs",
  "client_x509_cert_url": "client_x509_cert_url"
},
  "project_name": "project_name",
  "project_id": "project_id",
  "cluster_name": "numpy",
  "zone_region": "europe-west1-d",
  "services": "Single",
  "configuration": "",
  "routing": ""
}

Update: Now I have implemented apiview and serializers for these models. When I submit a post request with the services=Single without the values for configuration & routing it returns You haven't passed the correct data.

This means the save method, is not working. Help me, please!

Thanks in advance!

If you are using [DRF](http://www.django-rest-framework.org/), you can use [serializer validators](http://www.django-rest-framework.org/api-guide/validators/) — JPG, Jun 19 '18 at 08:15

JPG · Accepted Answer · 2018-06-28T10:43:17.083

2

apart from my comment, you could override the save() method of AwdModel model.


from django.core.exceptions import ValidationError


class AwdModel(UserAccountModel):
    source_zip = models.FileField(upload_to='media/awdSource/', name='awd_source')
    routing = models.TextField(name='routing', null=True)

    def save(self, **kwargs):
        if not self.id and self.services == 'Multiple' and not self.routing:
            raise ValidationError("error message")
        super().save(**kwargs)

self.id will be null or similar if it's a new instance,hence the validation checks happens only if instance is created

Update-1 use this payload to POST

{
  "deployment_name": "first_deployment",
  "credentials":{"test_key":"test_value"},
  "project_name": "project_name",
  "project_id": "project_id",
  "cluster_name": "numpy",
  "zone_region": "europe-west1-d",
  "services": "Single",
  "configuration": "",
  "routing": ""
}

update-2 try this for your serializer,

class DeploymentOnUserSerializer(serializers.ModelSerializer):
    credentials = serializers.JSONField()
    class Meta:
        model = DeploymentOnUserModel
        fields = '__all__'

edited Jun 28 '18 at 10:43

answered Jun 19 '18 at 09:08

JPG

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Hi @JerinPeterGeorge, I have updated the question, take a look, please! – Abdul Rehman Jun 28 '18 at 10:08
Mean post input object? – Abdul Rehman Jun 28 '18 at 10:12
the JSON data you passed to the view – JPG Jun 28 '18 at 10:12
Also add output of `print(serializer.errors)` . (add that print() after `validation = serializer.is_valid()` this statement) – JPG Jun 28 '18 at 10:15
`serializer.error` prints `{'credentials': ['Not a valid string.']}` – Abdul Rehman Jun 28 '18 at 10:24
look at `Update-1` – JPG Jun 28 '18 at 10:32
it still returns the same error and also `serializer.error` again said that `{'credentials': ['Not a valid string.']}` – Abdul Rehman Jun 28 '18 at 10:33
Then replace `{"test_key":"test_value"}` dict with some text as `"some text"` – JPG Jun 28 '18 at 10:36
for `credentials: "some_text"` it didn't return any error. – Abdul Rehman Jun 28 '18 at 10:39
I need to pass a json object for `credentials` . – Abdul Rehman Jun 28 '18 at 10:40

Make a model field as required on the base of a condition in Django Models

1 Answers1