Django : defining method inside the models - django

Question

serialize() method included in the django Tools_booked class but while trying to access that method it shows error.
'QuerySet' object has no attribute 'serialize'
models.py
from django.core.serializers import serialize
class UpdateQuerySet(models.QuerySet):
def serialize(self):
print("*****Entered the serizlize inside the UpdateQuerySet models **********")
qs = self
return serialize('json', qs, fields=('auto_increment_id','user','component','booked'))
class UpdateManager(models.Manager):
def get_queryset(self):
return UpdateQuerySet(self.model, using=self._db)
class Tools_booked(models.Model):
auto_increment_id = models.AutoField(primary_key=True)
user=models.ForeignKey(Profile, on_delete=models.CASCADE)
component = models.CharField(max_length=30, blank=True)
booked = models.DateTimeField(auto_now_add=True,blank=True)
objects = UpdateManager()
def __str__(self):
return self.component
def serialize(self):
json_data = serialize("json", [self], fields=['auto_increment_id','user','component','booked'])
stuct = json.loads(json_data)
print(struct)
data = json.dump(stuct[0]['fields'])
return data
views.py
class SerializedDetialView(View):
def get(self, request, *args, **kwargs):
print("*****Entered the SerializedDetialView **********")
obj_list= Tools_booked.objects.filter(auto_increment_id=1)
json_data = obj_list.serialize()
return HttpResponse(json_data, content_type='application/json')
class SerializedListView(View):
def get(self, request, *args, **kwargs):
json_data = Tools_booked.objects.all().serialize()
return HttpResponse(json_data, content_type='application/json')
The error traceback
json_data = Tools_booked.objects.all().serialize()
AttributeError: 'QuerySet' object has no attribute 'serialize'
But this works.
class SerializedDetialView(View):
def get(self, request, *args, **kwargs):
obj_list= Tools_booked.objects.filter(auto_increment_id=1)
json_data = serializers.serialize("json", obj_list )
return HttpResponse(json_data, content_type='application/json')
class SerializedListView(View):
def get(self, request, *args, **kwargs):
qs = Tools_booked.objects.all()
json_data = serializers.serialize("json", qs )
return HttpResponse(json_data, content_type='application/json')
How to use the serialize() method inside the models.py ,Tools_booked class.

Answer 1

You should either use Django-rest frameworks serializers with many=True or use values() function of Django queryset. There is no need to write a function in models. It will work like this
class YourSerializer(serializers.ModelSerializer):
class Meta:
model = "You Model Here"
fields = "write list of your model fields here or user __all__ for all fields"
you can serialize your query like this
queryset = Your_Model.objects.all()
serialized = YourSerializer(queryset, many=True).data
Other way to do so is like this
serialized = Your_Model.objects.all().values()
This method look simple but if you are writing rest apis, you should use serializers. You can look into details of serializer here.

Answer 2

Here is what's working for me:
from django.core.serializers import serialize
from django.db import models
class UpdateQuerySet(models.QuerySet):
def serialize(self):
print("*****Entered the serizlize inside the UpdateQuerySet models **********")
return serialize('json', self, fields=('component','booked'))
class UpdateManager(models.Manager):
# define here methods only needed inside this manager
pass
class Tools_booked(models.Model):
component = models.CharField(max_length=30, blank=True)
booked = models.DateTimeField(auto_now_add=True,blank=True)
objects = models.Manager()
serializer = UpdateManager.from_queryset(UpdateQuerySet)()
Now you can do in your views:
json_data = Tools_booked.serializer.serialize()
I guess you have an error because your serialize method is not defined inside the manager

Answer 3

In your models
class UpdateManager(models.Manager):
def get_queryset(self):
return UpdateQuerySet(self.model, self._db)
# Here for you to call to your views
def serialize(self):
return self.get_queryset().serialize()
In your views
json_data = Tools_booked.objects.all().serialize()
Django has changed a little bit.
Here is this document for Django update version.