How to add extra field to django serializer? - django

Question

I am trying to add an additional field to my serializer but I am getting the following error:-
"The field 'provider' was declared on serializer CreateUserSerializer, but has not been included in the 'fields' option."
Here is my serializer.py:-
class CreateUserSerializer(serializers.ModelSerializer):
email = serializers.EmailField()
username = serializers.CharField()
company = serializers.CharField()
provider = serializers.CharField()
password = serializers.CharField(write_only=True)
company_detail = serializers.SerializerMethodField()
branch_detail = serializers.SerializerMethodField()
def get_company_detail(self):
return {}
def get_branch_detail(self):
return {}
def create(self, validated_data):
try:
with transaction.atomic():
user = User.objects.create(**validated_data)
user_profile = UserProfileModel.objects.create(user=user)
user_profile.__dict__.update(**validated_data)
user_profile.save()
identity = FederatedIdentityModel.objects.create(user=user, oauth_provider=validated_data['provider'])
company = CompanyModel.objects.create(user=user, name=validated_data['company'])
branch = BranchModel.objects.create(user=user, name=validated_data['company'], company=company)
return user
except APIException:
raise APIException(
detail="Failed to register",
code=status.HTTP_500_INTERNAL_SERVER_ERROR
)
class Meta:
model = User
fields = ['first_name', 'last_name', 'password', 'email', 'username',
'company_detail', 'branch_detail']
I don't want to add the company and provider fields in the field option as it is not a part of user model. I just want to use them as writable fields so that I can create object for the two models.
How can I get rid of the following error?

Answer 1

I think you can't use that field without adding it to fields. What you can do is simply split model & extra fields into two lists and then define:
provider = serializers.CharField()
company = serializers.CharField()
...
class Meta:
model = User
model_fields = ['first_name', 'last_name', 'password', 'email', 'username',
'company_detail', 'branch_detail']
extra_fields = ['company', 'provider']
fields = model_fields + extra_fields

Answer 2

I found an alternative to solve this problem:-
class CreateUserSerializer(serializers.ModelSerializer):
email = serializers.EmailField()
company = serializers.CharField(write_only=True)
provider = serializers.ChoiceField(write_only=True, choices=OAUTH_PROVIDER_CHOICES)
password = serializers.CharField(write_only=True)
company_detail = serializers.SerializerMethodField()
branch_detail = serializers.SerializerMethodField()
# to get the details of company in response body
def get_company_detail(self, obj):
return {}
# to get the details of branch in response body
def get_branch_detail(self, obj):
return {}
def create(self, validated_data):
# pop additional fields from validated data to avoid error
company_name = validated_data.pop('company', None)
provider = validated_data.pop('provider', None)
try:
with transaction.atomic():
# create a user object
user = User.objects.create(**validated_data)
# create a user profile object
user_profile = UserProfileModel.objects.create(user=user)
user_profile.__dict__.update(**validated_data)
user_profile.save()
# create federated identity object using provider and email
identity = FederatedIdentityModel.objects.create(user=user, oauth_provider=provider,
email=validated_data['email'])
# create company object
company = CompanyModel.objects.create(user=user, name=company_name)
return user
except APIException:
raise APIException(
detail="Failed to register",
code=status.HTTP_500_INTERNAL_SERVER_ERROR
)
class Meta:
model = User
fields = ['first_name', 'last_name', 'password', 'email', 'username',
'company', 'provider', 'company_detail', 'branch_detail']
while creating user, I am popping the extra fields and using the popped value as the value while creating specific objects and adding the write_only=True in fields.
In that case, I can add the fields in my field_list without getting any error