Additional field while serializing django rest framework - django

Question

I am a newbie to django rest framework and have created a sample Employee model.
My models.py:
class Employees(models.Model):
created = models.DateTimeField(auto_now_add=True)
first_name = models.CharField(max_length=100)
last_name = models.CharField(max_length=100)
My serializers.py:
class EmployeeSerializer(serializers.Serializer):
class Meta:
model = Employees
fields = ('first_name','last_name')
This works fine but I want an additional field full_name, which will be first_name + last_name.
How do I define this new field full_name in my serializers.py?

Answer 1

I see two ways here (I prefer the first way since you can reuse it in other parts of the app):
add a calculated property to your model and add it to your serializer
by using a readonly field with source=
# models.py
class Employees(models.Model):
created = models.DateTimeField(auto_now_add=True)
first_name = models.CharField(max_length=100)
last_name = models.CharField(max_length=100)
#property
def full_name(self):
return self.first_name + self.last_name
# serializers.py
class EmployeeSerializer(serializers.ModelSerializer):
full_name = serializers.Field(source='full_name')
class Meta:
model = Employees
fields = ('first_name','last_name', 'full_name')
by using SerializerMethodField
(your model unchanged)
class EmployeeSerializer(serializers.ModelSerializer):
full_name = serializers.SerializerMethodField('get_full_name')
def get_full_name(self, obj):
return obj.first_name + obj.last_name
class Meta:
model = Employees
fields = ('first_name','last_name', 'full_name')

Answer 2

Provided that the Employee is a login user, then most of us will use django.auth.User, I will share how Employee can be implemented as another Profile (extension of django User). Also with the addition of full_name.read_only, first_name.write_only, and last_name.write_only
# models.py
class Employee(models.Model):
"""User Profile Model"""
user = models.OneToOneField('auth.User')
# serializers.py
class EmployeeSerializer(serializers.HyperlinkedModelSerializer):
username = serializers.CharField(source='user.username')
email = serializers.EmailField(source='user.email')
first_name = serializers.CharField(
source='user.first_name', write_only=True)
last_name = serializers.CharField(
source='user.last_name', write_only=True)
name = serializers.CharField(
source='user.get_full_name', read_only=True)
class Meta:
model = Employee
fields = (
'url', 'username', 'email',
'first_name', 'last_name', 'name')
depth = 1

Answer 3

SerializerMethodField works fine, and we can also store data in serializer object and let method get_field_name use that.
Example:
class MySerializer(serializers.ModelSerializer):
statistic = serializers.SerializerMethodField()
def __init__(self, instance=None, data=serializers.empty, statistic=None, **kwargs):
super(MySerializer, self).__init__(instance=instance, data=data, **kwargs)
self.statistic = statistic
def get_statistic(self, obj):
if self.statistic is None:
return serializers.empty
return self.statistic.get(obj.id, {})