Send Custom Error response from serializer in django rest framework? - django

Question

I want to send a custom response from serializers create view to front-end of my application. I tried rest framework Response tutorials but it does not work. My code is:
class UserSerializer(serializers.ModelSerializer):
"""Serializer to serialize user model object"""
class Meta:
model = User
fields = ('id', 'username', 'password', 'first_name', 'last_name')
extra_kwargs = {'password': {'write_only': True}}
def create(self, validated_data):
"""create a new user"""
firstname = self.initial_data['first_name']
lastname = self.initial_data['last_name']
fullname = str(firstname) +" "+ str(lastname)
email = self.initial_data['username'].lower()
try:
customer = User.create(
name=fullname,
email=email)
except Error as e:
error = {'message': e._message or 'Unknown error'}
return Response(error,status=status.HTTP_400_BAD_REQUEST)

Answer 1

serializers.py
class UserSerializer(serializers.ModelSerializer):
"""Serializer to serialize user model object"""
class Meta:
model = User
fields = ('id', 'username', 'password', 'first_name', 'last_name')
extra_kwargs = {'password': {'write_only': True}}
def create(self, validated_data):
"""create a new user"""
firstname = validated_data['first_name']
lastname = validated_data['last_name']
fullname = str(firstname) +" "+ str(lastname)
email = validated_data['username'].lower()
try:
customer = User.objects.create(
name=fullname,
email=email)
return customer
except Exception as e:
error = {'message': ",".join(e.args) if len(e.args) > 0 else 'Unknown Error'}
raise serializers.ValidationError(error)

Answer 2

So you want to change the representation of the User (the shape of the JSON response) from this view. To do this you need to change the .to_representation(self, obj) method in the serializer:
class UserSerializer(serializers.ModelSerializer):
"""Serializer to serialize user model object"""
class Meta:
model = User
fields = ('id', 'username', 'password', 'first_name', 'last_name',)
write_only_fields = ('id', 'password',)
def to_representation(self, obj):
return {
'firstname': obj.first_name,
'lastname': obj.last_name,
'fullname': obj.first_name+' '+obj.last_name,
'email': obj.username.lower()
}
This should mean that whenever a request is made that uses this serializer the user will only ever see those 4 fields in the JSON, e.g.
{
"firstname":"Salman",
"lastname": "Ahmed",
"fullname": "Salman Ahmed",
"email": "salman_ahmed#email.com"
}
More details on this is hidden in their docs here.