I have two models: FacebookAccount and Person. There's a OneToOne relationship like so:
class FacebookAccount(models.Model):
person = models.OneToOneField(Person, related_name='facebook')
name = models.CharField(max_length=50, unique=True)
page_id = models.CharField(max_length=100, blank=True)
I created a PersonSerializer which has a facebook field set to a FacebookSerializer I created:
class FacebookSerializer(serializers.ModelSerializer):
class Meta:
model = FacebookAccount
fields = ('name', 'page_id',)
class PersonSerializer(serializers.ModelSerializer):
facebook = FacebookSerializer(required=False)
class Meta:
model = Person
fields = ('id', 'name', 'facebook',)
I then created a view to create a new Person along with a new FacebookAccount instance for a POST request:
class PersonCreate(APIView):
def post(self, request):
# Checking for something here, doesn't affect anything
if 'token' in request.DATA:
serializer = PersonSerializer(data=request.DATA)
if serializer.is_valid():
serializer.save()
return Response(serializer.data, status=status.HTTP_201_CREATED)
return Response(serializer.errors, status=status.HTTP_400_BAD_REQUEST)
This works fine and well when my POST data has a facebook object with a unique name attribute in it. However, what if the facebook information is optional? I set "required=False" in the facebook field on the PersonSerializer to account for this, but I get a 400 error when my POST data does not contain a facebook object. The error says that the "name" field for facebook is required.
If I set "blank=True" on the name field in the FacebookAccount model and don't provide and facebook info in my POST data, a blank FacebookAccount record is created which is expected but not desired.
Does anyone know how to fix this? Thanks.
edit:
I tried overriding the save_object method on the PersonSerializer, but it looks like that method isn't called. I tried working my way back through the methods that are called, and it looks like get_field is the last one:
class PersonSerializer(serializers.ModelSerializer):
facebook = FacebookSerializer(required=False)
def get_default_fields(self):
field = super(PersonSerializer, self).get_default_fields()
print field
return field
def get_pk_field(self, model_field):
print 'MF'
mf = super(PersonSerializer, self).get_pk_field(model_field)
print mf
return mf
def get_field(self, model_field):
print 'FIELD'
mf = super(PersonSerializer, self).get_field(model_field)
print mf
return mf
# not called
def get_validation_exclusions(self, instance=None):
print '**Exclusions'
exclusions = super(PersonSerializer, self).get_validation_exclusions(instance=None)
print exclusions
return exclusions
# not called
def save_object(self, obj, **kwargs):
if isinstance(obj, FacebookAccount):
print 'HELLO'
else:
print '*NONONO'
return super(PersonSerializer, self).save_object(obj, **kwargs)
class Meta:
model = Person
fields = ('id', 'name', 'stripped_name', 'source', 'facebook',)
The ModelSerializer class is the same as a regular Serializer class, except that: It will automatically generate a set of fields for you, based on the model. It will automatically generate validators for the serializer, such as unique_together validators. It includes simple default implementations of .
In function-based views, we can pass extra context to serializer with “context” parameter with a dictionary. To access the extra context data inside the serializer we can simply access it with “self. context”. From example, to get “exclude_email_list” we just used code 'exclude_email_list = self.
Serializers in Django REST Framework are responsible for converting objects into data types understandable by javascript and front-end frameworks. Serializers also provide deserialization, allowing parsed data to be converted back into complex types, after first validating the incoming data.
Serializer Method Field It gets its value by calling a method on the serializer class it is attached to. It can be used to add any sort of data to the serialized representation of your object. SerializerMethodField gets its data by calling get_<field_name> . Example: class UserSerializer(serializers.
Simply pass allow_null=True
when declaring the nested serializer in the parent serializer, like this:
class FacebookSerializer(serializers.ModelSerializer):
class Meta:
model = FacebookAccount
fields = ('name', 'page_id',)
class PersonSerializer(serializers.ModelSerializer):
facebook = FacebookSerializer(allow_null=True, required=False)
class Meta:
model = Person
fields = ('id', 'name', 'facebook',)
Well, that is the limitation of django-restframework when specifying reverse relation as a field, because it creates a list from the fields specified , required=false only directs the serializer to save the default null value for that related field, to resolve it you can override save_object method of serializer and remove facebook field if its null.
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