This is just a layout of my serializer
class SerializerA(serializers.ModelSerializer):
field_a = serializers.SerializerMethodField()
field_b = serializers.SerializerMethodField()
field_c = serializers.SerializerMethodField()
field_d = serializers.SerializerMethodField()
class Meta:
model = TestModel
fields = ("field_a", "field_b", "field_c", "field_d", "name", "designation")
def get_field_a(self, obj):
temp = TempUserModel.objects.get(pk=obj.uuid)
field_a = "some ORM query related to temp and TestModel model"
return field_a
def get_field_b(self, obj):
temp = TempUserModel.objects.get(pk=obj.uuid)
field_b = "some ORM query related to temp and TestModel model"
return field_b
def get_field_c(self, obj):
temp = TempUserModel.objects.get(pk=obj.uuid)
field_c = "some ORM query related to temp and TestModel model"
return field_c
def get_field_d(self, obj):
field_d = "some ORM query related to TestModel model"
return field_d
Here temp = TempuserModel.objects.get(pk=obj.uuid) is same in 3 out of 4 of the class methods. So is there any way that I can define it once somewhere in a serializer loop and use it without doing the same ORM query again and again?
Related
I need help with REST Framework. I have to do my test for internship position and I have two models with circular import 'Pokemon' model and 'Team' mode. In serializer of 'Team' I have this code
class TeamDetailsSerializer(ModelSerializer):
"""Serializer for details of Team instances"""
pokemon_1 = SerializerMethodField()
pokemon_2 = SerializerMethodField()
pokemon_3 = SerializerMethodField()
pokemon_4 = SerializerMethodField()
pokemon_5 = SerializerMethodField()
trainer = UserSerializer()
class Meta:
model = Team
fields = (
"trainer",
"name",
"pokemon_1",
"pokemon_2",
"pokemon_3",
"pokemon_4",
"pokemon_5",
)
read_only_fields = ("id",)
# Methods to relate each Pokemon object
def get_pokemon_1(self, obj):
pokemon_1 = obj.pokemon_1
if not pokemon_1:
return None
serializer = pokemon.serializers.PokemonDetailsSerializer(pokemon_1)
return serializer.data
def get_pokemon_2(self, obj):
pokemon_2 = obj.pokemon_2
if not pokemon_2:
return None
serializer = pokemon.serializers.PokemonDetailsSerializer(pokemon_2)
return serializer.data
def get_pokemon_3(self, obj):
pokemon_3 = obj.pokemon_3
if not pokemon_3:
return None
serializer = pokemon.serializers.PokemonDetailsSerializer(pokemon_3)
return serializer.data
def get_pokemon_4(self, obj):
pokemon_4 = obj.pokemon_4
if not pokemon_4:
return None
serializer = pokemon.serializers.PokemonDetailsSerializer(pokemon_4)
return serializer.data
def get_pokemon_5(self, obj):
pokemon_5 = obj.pokemon_5
if not pokemon_5:
return None
serializer = pokemon.serializers.PokemonDetailsSerializer(pokemon_5)
return serializer.data
and problem that I get this kind of schema
name* [...]
trainer* User{...}
pokemon_1 integer
nullable: true
pokemon_2 [...]
pokemon_3 [...]
pokemon_4 [...]
pokemon_5 [...]
but I would like to get object type, what kind of solutions I can apply?
Thank a lot
I am trying to create a relationship between databases
result : =>
[
{
"id":1,
"title":"mobile",
"category_two":[
{
"id":3,
"title":"brand"
},
{
"id":4,
"title":"memory"
}
]
}
]
and i expect : =>
[
{
"id":1,
"title":"mobile",
"category_two":[
{
"id":3,
"title":"brand",
"category_three":[
{
"id":1,
"title":"samsung"
},
{
"id":2,
"title":"apple"
}
]
},
{
"id":4,
"title":"memory",
"category_three":[
{
"id":1,
"title":"32gb"
},
{
"id":2,
"title":"64gb"
}
]
}
]
}
]
// views
class get_Category(APIView):
def get(self, request):
category = CategoryOne.objects.all()
serializer = CategoryTwoSerializer(category, many=True)
return Response(serializer.data)
//serializers
class CategoryOneSerializer(serializers.ModelSerializer):
class Meta:
model = CategoryOne
fields = '__all__'
class CategoryTwoSerializer(serializers.ModelSerializer):
category_two= CategoryOneSerializer(many=True,read_only=True)
class Meta:
model = CategoryTwo
fields = '__all__'
depth=5
class CategoryThreeSerializer(serializers.ModelSerializer):
category_three = CategoryTwoSerializer(many=True,read_only=True)
class Meta:
model = CategoryThree
fields = '__all__'
depth=5
// models
class CategoryOne(models.Model):
title = models.CharField(max_length=225)
def __str__(self):
return self.title
class CategoryTwo(models.Model):
title = models.CharField(max_length=255)
categoryone = models.ForeignKey(CategoryOne,related_name='category_two',on_delete=models.SET_NULL,null=True)
def __str__(self):
return self.title
class CategoryThree(models.Model):
title = models.CharField(max_length=255)
categorytwo = models.ForeignKey(CategoryTwo,related_name='category_three',on_delete=models.SET_NULL,null=True)
def __str__(self):
return self.title
Try
class CategoryOneSerializer(serializers.ModelSerializer):
category_two= CategoryTwoSerializer(many=True,read_only=True)
class Meta:
model = CategoryOne
fields = '__all__'
class CategoryTwoSerializer(serializers.ModelSerializer):
category_three = CategoryThreeSerializer(many=True,read_only=True)
class Meta:
model = CategoryTwo
fields = '__all__'
class CategoryThreeSerializer(serializers.ModelSerializer):
class Meta:
model = CategoryThree
fields = '__all__'
// views
class get_Category(APIView):
def get(self, request):
category = CategoryOne.objects.prefetch_related("category_two", "category_two__category_three")
serializer = CategoryOneSerializer(category, many=True)
return Response(serializer.data)
If you want category_two rows related to a specific category_one to be serialized with it, you essentially want to add a non existing data to CategoryOne.
Since means you need two add it to the serializer and specify how to serialize it.
Here you can access this data by using a related_name, therefore adding a field with the proper related_name will suffice for django to find the data you want.
The same wan be done the serializer CategoryThree tied the a specific CategoryTwo row.
Howerver doing this will produce a LOT of SQL queries since each time my_category_on.category_two.all() is called by the serializer, an sql query is needed.
The prefetch_related() is here to solve the issue
I am new in Django and I would like to overwrite the field value in create and update method of serializer. Here is my model=>
class Holiday(models.Model):
HolidayDay = models.DateField()
Created_DT = models.DateTimeField()
Created_Usr = models.CharField(max_length=20)
LastModified_Usr = models.CharField(max_length=20,blank=True)
LastModified_DT = models.DateTimeField(blank=True,null=True)
def __str__(self):
return str(self.HolidayDay)
Here is my serializer=>
class HolidaySerializer(serializers.ModelSerializer):
class Meta:
model=Holiday
fields = [
'id',
'HolidayDay',
'Created_DT',
'Created_Usr',
'LastModified_Usr',
'LastModified_DT'
]
def create(self,validated_data):
validated_data['Created_Usr'] ="Testing"
return Holiday.objects.create(**validated_data)
I would like to update Create_usr field value in create method and LastModified_usr field in update method. But why I can't overwrite the create_usr field as "Testing"?
Here is my views=>
def post(self,request):
holiday = request.data.get('holiday')
serializer = HolidaySerializer(data=holiday)
serializer.is_valid()
print(serializer.errors)
if serializer.is_valid():
holiday_saved=serializer.save()
return Response({"success":"Holiday '{}' created successfully".format(holiday_saved.HolidayDay)})
def put(self,request,pk):
save_holiday = get_object_or_404(Holiday.objects.all(),pk=pk)
data = request.data.get('holiday')
serializer = HolidaySerializer(instance=save_holiday,data=data,partial=True)
if serializer.is_valid(raise_exception = True):
holiday_saved=serializer.save()
return Response({"sucess": "Holiday '{}' updated successfully".format(holiday_saved.HolidayDay)})
Your create method is not defined in your Serializer class, instead it is part of your Meta class. You should be able to solve it by moving your create method to your HolidaySerializer:
class HolidaySerializer(serializers.ModelSerializer):
def create(self,validated_data):
validated_data['Created_Usr'] = "Testing"
return Holiday.objects.create(**validated_data)
class Meta:
model=Holiday
fields = [
'id',
'HolidayDay',
'Created_DT',
'Created_Usr',
'LastModified_Usr',
'LastModified_DT'
]
I want to change ManyToManyField Name. user_groups is manytomanyfield. I tried to use ManyToManyRelatedField and also PrimaryKeyRelatedField but it is giving error. How can i change or with data type should i give like for character field i am giving CharField
class EmployeeProfileSerializer(serializers.ModelSerializer):
employee_id = serializers.CharField(source='user_employee_id')
payroll_id = serializers.CharField(source='user_payroll_id')
phone = serializers.CharField(source='user_phone')
hire_date = serializers.DateField(source='user_hire_date')
pay_rate = serializers.IntegerField(source='user_pay_rate')
salaried = serializers.CharField(source='user_salaried')
excempt = serializers.CharField(source='user_excempt')
state = serializers.CharField(source='user_state')
city = serializers.CharField(source='user_city')
zipcode = serializers.IntegerField(source='user_zipcode')
status = serializers.CharField(source='user_status')
class Meta:
model = UserProfile
fields = [
'employee_id',
'phone',
'payroll_id',
'hire_date',
'pay_rate',
'salaried',
'excempt',
'state',
'city',
'zipcode',
'status',
'user_groups',
]
You can use SerializerMethodField:
class EmployeeProfileSerializer(serializers.ModelSerializer):
...
your_custom_name = SerializerMethodField()
class Meta:
model = UserProfile
fields = ['your_custom_name ', ...]
def get_your_custom_name(self, obj):
# Return ids:
return list(obj.user_groups.all().values_list('pk', flat=True))
# Or using a serializer:
return MyUserGroupSerializer(obj.user_groups.all(), many=True).data
For create and update you have to override the create and update method to assign the new field:
class EmployeeProfileSerializer(serializers.ModelSerializer):
...
your_custom_name = IntegerField()
class Meta:
model = UserProfile
fields = ['your_custom_name', ...]
# If you need validation
def validate_your_custom_name(self, value):
if value:
if int(value) > 5:
return value
return None
def create(self, validated_data):
# Get the data for your new field
my_costum_data = validated_data.get('your_custom_name')
# Do something with it
profile_obj = UserProfile.objects.create(...)
if my_costum_data:
user_group = UserGroupModel.objects.get(pk=int(my_costum_data))
profile_obj.user_groups.add(user_group)
def update(self, instance, validated_data):
# Same as create()
...
How to serialize a fields in related models.
I got a models:
class Order(models.Model):
order_id = models.BigIntegerField(verbose_name='Order ID', unique=True)
order_name = models.CharField(verbose_name='Order name', max_length=255)
order_type = models.IntegerField(verbose_name='Campaign type')
class Types(models.Model):
delimiter = models.CharField(verbose_name='Delimiter', max_length=255)
status = models.BooleanField(verbose_name='Status', default=True)
title = models.CharField(verbose_name='Title', max_length=255)
class User(models.Model):
name = models.CharField(verbose_name='User name', max_length=200, unique=True)
class Report(models.Model):
order = models.ForeignKey(Order, to_field='order_id', verbose_name='Order ID')
user = models.ForeignKey(User, verbose_name='User ID')
ad_type = models.ForeignKey(Types, verbose_name='Type')
imp = models.IntegerField(verbose_name='Total imp')
month = models.DateField(verbose_name='Month', default=datetime.datetime.today)
View:
class ReportLisAPIView(ListAPIView):
serializer_class = ReportSerializer
def get_queryset(self):
month = parse_date(self.kwargs['month']) - relativedelta(day=1)
queryset = (
Report.objects.filter(month=month)
.values_list(
'user', 'user__name', 'order__order_id',
'order__order_name', 'order__order_type'
).all().annotate(Sum('imp'))
)
return queryset
Serializer:
class ReportSerializer(ModelSerializer):
class Meta:
model = Report
depth = 1
I need to get all field like in 'queryset' in get_queryset()
but I got an error:
Got AttributeError when attempting to get a value for field imp on
serializer ReportSerializer. The serializer field might be named
incorrectly and not match any attribute or key on the tuple
instance. Original exception text was: 'tuple' object has no attribute
'imp'.
But if I return in get_queryset() just Report.objects.filter(month=month).all() I'll get all objects and related object with all field, without aggregate of imp and not grouping.
So the question is how to make serializer return structure that set in queryset?
The get_queryset method requires to return a queryset but you are returning a tuple beacause of values_list. Either drop it to return a queryset or go with a more generic view like APIView.
I found a way how to do it.
As I use .values_list() it return list object instead of queryset object. So for serializer do understand what is inside the list I defined all fields in serializer. And in to_representation() I return dictionary like it should be.
Serializer:
class ReportSerializer(serializers.ModelSerializer):
user = serializers.IntegerField()
user_name = serializers.CharField()
order_id = serializers.IntegerField()
order_name = serializers.CharField()
order_type = serializers.IntegerField()
imp = serializers.IntegerField()
class Meta:
model = Report
fields = [
'user', 'user_name', 'order_id', 'order_name',
'order_type', 'imp'
]
depth = 1
def to_representation(self, instance):
Reports = namedtuple('Reports', [
'user',
'user_name',
'order_id',
'order_name',
'order_type',
'imp',
])
return super(ReportSerializer, self).to_representation(
Reports(*instance)._asdict()
)
View:
class ReportLisAPIView(ListAPIView):
serializer_class = ReportSerializer
def get_queryset(self):
month = parse_date(self.kwargs['month']) - relativedelta(day=1)
queryset = (
Report.objects.filter(month=month)
.values_list(
'user', 'user__name', 'order__order_id',
'order__order_name', 'order__order_type'
).all().annotate(Sum('imp'))
)
return queryset
def list(self, *args, **kwargs):
queryset = self.get_queryset()
serializer = self.serializer_class(queryset, many=True)
# actualy that's it! part of which is below can be pass and just
# return Response(serializer.data)
result = {
'month': parse_date(self.kwargs['month']).strftime('%Y-%m'),
'reports': []
}
inflcr = {}
for item in serializer.data:
inflcr.setdefault(item['user'], {
'id': item['user'],
'name': item['user_name'],
'campaigns': []
})
orders = {
'id': item['order_id'],
'name': item['order_name'],
'type': item['order_type'],
'impressions': item['imp'],
}
inflcr[item['user']]['campaigns'].append(orders)
result['reports'] = inflcr.values()
return Response(result)