I have those models:
class ServiceCategory(models.Model):
class Meta:
db_table = 'service_categories'
category = models.CharField(max_length=24)
def __str__(self):
return self.category
class Service(models.Model):
class Meta:
db_table = 'services'
service = models.CharField(max_length=24)
category = models.ForeignKey('ServiceCategory')
def __str__(self):
return self.service
And their serializers:
class ServiceCategorySerializer(serializers.ModelSerializer):
class Meta:
model = ServiceCategory
fields = ('id', 'category')
class ServiceSerializer(serializers.ModelSerializer):
category = ServiceCategorySerializer()
class Meta:
model = Service
fields = ('id', 'service', 'category')
After this setup, I quickly bumped into a problem creating a new Service via its associated ServiceSerializer: I have to also pass a complete ServiceCategory with all its fields even though I only need its id. The ServiceCategory above looks simple enough but that's hardly the case since I've omitted a lot of its other fields for brevity.
So passing the complete attributes of a ServiceCategory into a form on the front end seemed terribly inefficient to me so I tried another approach:
class UpsertServiceSerializer(serializers.ModelSerializer):
category = serializers.IntegerField() # not ServiceCategorySerializer()
class Meta:
model = Service
fields = ('service', 'category')
def create(self, data):
c = ServiceCategory.objects.get(pk=data['category'])
return Service.objects.create(service=data['service'], category=c)
My intention is to use UpsertServiceSerializer for creates and updates, with ServiceSerializer now being used for reads. UpsertServiceSerializer worked without a problem in the Django shell — the create goes through with me having to pass just the id of the ServiceCategory instead of all its attributes and a new Service object is indeed added to the database — but when I make a POST request via Postman, I get this error:
TypeError at /services
int() argument must be a string, a bytes-like object or a number, not 'ServiceCategory'
So I tried a new version of UpsertServiceSerializer:
class UpsertServiceSerializer(serializers.Serializer):
service = serializers.CharField()
category = serializers.IntegerField()
def create(self, data):
c = ServiceCategory.objects.get(pk=data['category'])
return Service.objects.create(service=data['service'], category=c)
Notice that in the new version, I'm subclassing serializers.Serializer instead of serializers.ModelSerializer, and there's no class Meta inside it. This version is no different, it also passes in the Django shell but fails in the view with the same TypeError.
Here's the view:
#api_view(['GET', 'POST'])
def services(request):
if request.method == 'GET':
services = Service.objects.all()
serializer = ServiceSerializer(services, many=True)
return Response(serializer.data)
elif request.method == 'POST':
serializer = UpsertServiceSerializer(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)
So what am I doing wrong?
It is common problem with understanding about how related fields work in serializer. ForeignKey by default use PrimaryKeyRelatedField so you don't need an IntegerField, even though you don't need overriding create method.
class UpsertServiceSerializer(serializers.ModelSerializer):
class Meta:
model = Service
fields = ('service', 'category')
Passing pk for category will just work. In the case when you need special layout for category model not a plain pk, you could write you own to_representation method.
class UpsertServiceSerializer(serializers.ModelSerializer):
...
def to_representation(self, instance):
representation = super(UpsertServiceSerializer, self).to_representation(instance)
representation['category'] = ServiceCategorySerializer(instance.category).data
return representation
Related
I have this Serializer
class RemovePermissionsSerializer(serializers.ModelSerializer):
user_permissions = serializers.SerializerMethodField()
def get_user_permissions(self, instance):
print(1)
**logic**
return data
class Meta:
model = User
fields = [
"user_permissions"
]
and a generic viewset with this action
#action(
methods=["patch", "put"],
detail=True,
url_name="add-permissions",
url_path="add-permissions"
)
def add_permissions_request(self, request, pk):
serializer = self.get_serializer(data=request.data)
serializer.is_valid(raise_exception=True)
user = self.get_object()
user_permissions = serializer.validated_data.get("user_permissions")
response = User.add_permissions(user, user_permissions)
return Response(response, status=status.HTTP_200_OK)
the function get_user_permissions is not being called whatever I put in it, even print() is not showing anything, any help please?
Here you use the serializer in the other way. A SerializerMethodField is read-only: since a function is always input to output. Here you are trying to work with it in the write direction.
This is one of the many reasons why using a SerializerMethodField is often not a good idea.
Usually it makes more sense to work with a sub-serializer, a PrimaryKeyRelatedField [drf-doc], or a SlugRelatedField [drf-doc].
You can for example use:
from django.contrib.auth.models import Permission
class PermissionSerializer(serializers.ModelSerializer):
class Meta:
model = Permission
fields = ['__all__']
class RemovePermissionsSerializer(serializers.ModelSerializer):
user_permissions = PermissionSerializer(source='permission', many=True)
class Meta:
model = User
fields = ['user_permissions']
then you specify all the details of the permission, or you can work with a PrimaryKeyRelatedField or SlugRelatedField to let the user specify the primary key of the permission, or some other field ("slug"):
from django.contrib.auth.models import Permission
class RemovePermissionsSerializer(serializers.ModelSerializer):
user_permissions = serializers.PrimaryKeyRelatedField(
source='permission', many=True, queryset=Permission.objects.all()
)
class Meta:
model = User
fields = ['user_permissions']
I am trying to update my Teachers view in DRF by instead of including the link to the department field, I would display the name of the department. When I added the PrimaryKeyRelated field, I was able to see the department.name but couldnt use update or create within DRF. Is there a way I could change the display without causing the need for the methods or is that not the case?
Error
The `.update()` method does not support writable dotted-source fields by default.
Write an explicit `.update()` method for serializer `school.serializers.TeacherSerializer`, or set `read_only=True` on dotted-source serializer fields.
The `.create()` method does not support writable dotted-source fields by default.
Write an explicit `.create()` method for serializer `school.serializers.TeacherSerializer`, or set `read_only=True` on dotted-source serializer fields.
models.py
class Department(models.Model):
name = models.CharField(max_length=300)
def __str__(self):
return self.name
class Teacher(models.Model):
name = models.CharField(max_length=300)
department = models.ForeignKey(Department, on_delete=models.CASCADE)
tenure = models.BooleanField()
def __str__(self):
return f'{self.name} teaches {self.department}'
# dont need success url if get_absolute_url on create and update view
def get_absolute_url(self):
return reverse('teacher', kwargs={'pk': self.pk})
serializers.py
class TeacherSerializer(serializers.HyperlinkedModelSerializer):
department = serializers.PrimaryKeyRelatedField(
source='department.name', queryset=Department.objects.all())
class Meta:
model = Teacher
fields = ['url', 'name', 'department', 'tenure']
class DepartmentSerializer(serializers.HyperlinkedModelSerializer):
teacher_set = TeacherSerializer(many=True, required=False)
class Meta:
model = Department
fields = ['url', 'name', 'teacher_set']
views.py
class TeacherViewSet(viewsets.ModelViewSet):
queryset = Teacher.objects.all()
serializer_class = TeacherSerializer
permission_classes = [permissions.IsAuthenticatedOrReadOnly]
class DepartmentViewSet(viewsets.ModelViewSet):
queryset = Department.objects.all()
serializer_class = DepartmentSerializer
permission_classes = [permissions.IsAuthenticatedOrReadOnly]
have you tried add related_name for model Teacher in field foreign key and call in serializers? link to docs
I have two models first as parent model "Country", that filled before the second one as child model "City". as the following
class Country(models.Model):
name = models.CharField(max_length=35)
icon = models.ImageField()
def __str__(self):
return self.name
class City(models.Model):
name = models.CharField(max_length=35)
country = models.ForeignKey(to=Country, on_delete=models.CASCADE)
def __str__(self):
return self.name
My serializers.py for my need as following :
class CountrySerializer(ModelSerializer):
class Meta:
model = Country
fields = '__all__'
class CitySerializer(ModelSerializer):
country = serializers.PrimaryKeyRelatedField(queryset=Country.objects.all())
class Meta:
model = City
fields = ('name', 'country')
view.py
class CountryAPIView(ListAPIView):
queryset = Country.objects.all()
serializer_class = CountrySerializer
permission_classes = [AllowAny, AllowAnonymous]
class CityAPIView(ListAPIView):
queryset = City.objects.all()
serializer_class = CitySerializer
permission_classes = [AllowAny, AllowAnonymous]
def post(self, request):
serializer = CitySerializer(data=request.data)
if serializer.is_valid(raise_exception=ValueError):
serializer.create(validated_data=request.data)
return Response(serializer.data, status=status.HTTP_201_CREATED)
return Response(serializer.error_messages,
status=status.HTTP_400_BAD_REQUEST)
now when i run get api it run and gives me a result fine . But when im trying to create a new city and set "country":"id" in json i got this error
Cannot assign "2": "City.country" must be a "Country" instance.
So if i was not clear ,, what i need is exactly set foreign key to city when i create city ,, not create city and country,,
please any one had a solution help, because i tried many ways and read the django rest framework docs about this point but i didn't got it.
First of all, the raise_exception should be a boolean value (either True or False)
You could avoid this error by using inheriting the view class from ListCreateAPIView
from rest_framework.generics import ListCreateAPIView
class CityAPIView(ListCreateAPIView):
queryset = City.objects.all()
serializer_class = CitySerializer
permission_classes = [AllowAny, AllowAnonymous]
You don't want to use the post() method if you're using ListCreateAPIView, because DRF will take care of that part well.
Suggestion
Since you're dealing with CRUD functionalities of the model, you can use the DRF's ModelViewset class
you are not using the validated data to create a new city, just change this line:
serializer.create(validated_data=request.data)
to this:
serializer.save()
when you perform serializer.save(), the serializer will use its validated data.
also, DRF has a generic view(ListCreateAPIView) that covers your use-case.
I'm working on a Django Rest Framework project, in which I have created the following models as:
from django.db import models
# Base Models...
choices = (
('Single', 'Single'),
('Multiple', 'Multiple'),
)
class UserAccountModel(models.Model):
deployment_name = models.CharField(max_length=150, blank=True)
credentials = models.FileField(upload_to='media/credentials/', name='credentials'),
project_name = models.CharField(max_length=150, blank=True)
project_id = models.CharField(max_length=100, blank=False, name='project_id')
cluster_name = models.CharField(max_length=150, blank=False)
zone_region = models.CharField(max_length=150, blank=False)
services = models.CharField(max_length=100, choices=choices)
def __str__(self):
return self.deployment_name
class AwdModel(UserAccountModel):
source_zip = models.FileField(upload_to='media/awdSource/', name='awd_source')
routing = models.TextField(name='routing', null=True)
def __str__(self):
return self.deployment_name
def save(self, **kwargs):
if not self.id and self.services == 'Multiple' and not self.routing:
raise ValidationError("You must have to provide routing for multiple services deployment.")
super().save(**kwargs)
# def clean(self):
# if self.services == 'Multiple' and self.routing is None:
# raise ValidationError('You must have to provide routing for multiple services deployment.')
class AwodModel(UserAccountModel):
source_zip = models.FileField(upload_to='media/awodSource/', name='awod_source')
routing = models.TextField({'type': 'textarea'}, name='routing')
def save(self, **kwargs):
if not self.id and self.services == 'Multiple' and not self.routing:
raise ValidationError("You must have to provide routing for multiple services deployment.")
super().save(**kwargs)
I need to serialize these models, Here's how I have implemented serializers for these models:
from rest_framework import serializers
from .models import UserAccountModel, AwdModel, AwodModel
class UserAccountSerializer(serializers.ModelSerializer):
class Meta:
model = UserAccountModel
fields = ('deployment_name', 'credentials', 'project_name',
'project_id', 'cluster_name', 'zone_region', 'services')
class AWDSerializer(serializers.ModelSerializer):
class Meta(UserAccountSerializer.Meta):
model = AwdModel
fields = UserAccountSerializer.Meta.fields + ('awd_source', 'routing',)
class AWODSerializer(serializers.ModelSerializer):
class Meta:
model = AwodModel
fields = '__all__'
But, when I try to access, AWDSerialzer it return an error as:
AttributeError at /api/v1/deployments/
Got AttributeError when attempting to get a value for field project_id on serializer AWDSerializer.
The serializer field might be named incorrectly and not match any attribute or key on the QuerySet instance.
Original exception text was: 'QuerySet' object has no attribute 'project_id'.
Update: Here's my APIView code:
class DeploymentsList(APIView):
def get(self, request):
MAX_OBJECTS = int(20)
deployments = AwdModel.objects.all()[:MAX_OBJECTS]
data = AWDSerializer(deployments).data
return Response(data)
class DeploymentDetail(APIView):
def get(self, request, *args, **kwargs):
deployment = get_object_or_404(AwdModel, pk=kwargs['pk'])
data = AWDSerializer(deployment).data
return Response(data)
Help me, please!
Thanks in advance!
AttributeError at /api/v1/deployments/ Got AttributeError when
attempting to get a value for field project_id on serializer
AWDSerializer. The serializer field might be named incorrectly and not
match any attribute or key on the QuerySet instance. Original
exception text was: 'QuerySet' object has no attribute 'project_id'.
This is an attribute error, when attempting to get the value from field project_id .
Get rid of the name attribute in the project_id field.
Edit The APIView code
To serialize a queryset or list of objects instead of a single object
instance, you should pass the many=True flag when instantiating the
serializer. You can then pass a queryset or list of objects to be
serialized. [Serializing multiple objects]
class DeploymentsList(APIView):
def get(self, request):
MAX_OBJECTS = int(20)
deployments = AwdModel.objects.all()[:MAX_OBJECTS]
data = AWDSerializer(deployments, many=True).data
return Response(data)
I hope this will help.
The code that you posted appears to be valid and correct. The issue however is unrelated. The exception text 'QuerySet' object has no attribute 'project_id' Refers to an issue that likely originates from your restframework app's views.py file. The exception states that you are attempting to access the attribute 'project_id' from a QuerySet.
A QuerySet is a (lazy loaded) set of models and not a single model. Even if the query set had only one element you'd still be required to access that element before accessing it's attributes.
Because you haven't shared your views.py file I can't say for sure where the issue is however here is an incorrect use case example: MyModel.objects.all().project_id. Here we can see that I am attempting to access the attribute project_id from a query set. A correct use case would be MyModel.objects.all()[0].project_id. However this assumes that the query set is not empty.
Practically, most DjangoRestFramework views inherit from rest_framework.views.APIView which subclasses django's View Class. I would suggest checking the query_set within that class is being used correctly.
Feel free to share your implementation here for further comment.
[EDIT] - After views.py coded was added.
You are attempting to serializer an entire query set with the instantiation of a serializer data = AWDSerializer(deployments).data this is causing the attribute error.
I would recommend the generics.ListAPIView class and the use of the class attributes query_set and serializer_class. These are simple to implement. You can then invoke the APIViews default get method. Here is an example for your DeploymentsList view
from rest_framework import generics
class DeploymentsList(generics.ListAPIView):
serializer_class = AWDSerializer
queryset = AwdModel.objects.all()
def get(self, request, *args, **kwargs):
MAX_OBJECTS = int(20)
self.queryset = self.queryset[:MAX_OBJECTS]
return super(DeploymentsList, self).get(request, *args, **kwargs)
[EDIT] - FileField Serialization
In order to serialize the UserAccount.credentials file field so that we serializer the path, we can use the serializers.SerializerMethodField. I.e Your UserAccountSerializer becomes:
class UserAccountSerializer(serializers.ModelSerializer):
credentials = serializers.SerializerMethodField()
def get_credentials(self, user_account):
return user_account.credentials.path
class Meta:
model = UserAccountModel
fields = ('deployment_name', 'credentials', 'project_name',
'project_id', 'cluster_name', 'zone_region', 'services')
When you inherit from a model class which is not defined as abstract in it’s own meta class, then Django creates a one-to-one relation between the subclass and its parent. Which actually creates two tables in the database; one for the base class and one for the subclass.
I haven’t tried your code, nor used Django 2, but would check using a relational field between the two serializer.
I've tried something like this, it does not work.
class PostSerializer(serializers.ModelSerializer):
class Meta:
model = Post
def save(self):
user = self.context['request.user']
title = self.validated_data['title']
article = self.validated_data['article']
I need a way of being able to access request.user from my Serializer class.
You cannot access the request.user directly. You need to access the request object, and then fetch the user attribute.
Like this:
user = self.context['request'].user
Or to be more safe,
user = None
request = self.context.get("request")
if request and hasattr(request, "user"):
user = request.user
More on extra context can be read here
Actually, you don't have to bother with context. There is a much better way to do it:
from rest_framework.fields import CurrentUserDefault
class PostSerializer(serializers.ModelSerializer):
class Meta:
model = Post
def save(self):
user = CurrentUserDefault() # <= magic!
title = self.validated_data['title']
article = self.validated_data['article']
As Igor mentioned in other answer, you can use CurrentUserDefault. If you do not want to override save method just for this, then use doc:
from rest_framework import serializers
class PostSerializer(serializers.ModelSerializer):
user = serializers.PrimaryKeyRelatedField(read_only=True, default=serializers.CurrentUserDefault())
class Meta:
model = Post
CurrentUserDefault
A default class that can be used to represent the current user. In order to use this, the 'request' must have been provided as part of the context dictionary when instantiating the serializer.
in views.py
serializer = UploadFilesSerializer(data=request.data, context={'request': request})
This is example to pass request
in serializers.py
owner = serializers.HiddenField(
default=serializers.CurrentUserDefault()
)
Source From Rest Framework
Use this code in view:
serializer = UploadFilesSerializer(data=request.data, context={'request': request})
then access it with this in serializer:
user = self.context.get("request").user
For those who used Django's ORM and added the user as a foreign key, they will need to include the user's entire object, and I was only able to do this in the create method and removing the mandatory field:
class PostSerializer(serializers.ModelSerializer):
def create(self, validated_data):
request = self.context.get("request")
post = Post()
post.title = validated_data['title']
post.article = validated_data['article']
post.user = request.user
post.save()
return post
class Meta:
model = Post
fields = '__all__'
extra_kwargs = {'user': {'required': False}}
You can pass request.user when calling .save(...) inside a view:
class EventSerializer(serializers.ModelSerializer):
class Meta:
model = models.Event
exclude = ['user']
class EventView(APIView):
def post(self, request):
es = EventSerializer(data=request.data)
if es.is_valid():
es.save(user=self.request.user)
return Response(status=status.HTTP_201_CREATED)
return Response(data=es.errors, status=status.HTTP_400_BAD_REQUEST)
This is the model:
class Event(models.Model):
user = models.ForeignKey(to=settings.AUTH_USER_MODEL, on_delete=models.CASCADE)
date = models.DateTimeField(default=timezone.now)
place = models.CharField(max_length=255)
You can not access self.context.user directly. First you have to pass the context inside you serializer. For this follow steps bellow:
Some where inside your api view:
class ApiView(views.APIView):
def get(self, request):
items = Item.object.all()
return Response(
ItemSerializer(
items,
many=True,
context=request # <- this line (pass the request as context)
).data
)
Then inside your serializer:
class ItemSerializer(serializers.ModelSerializer):
current_user = serializers.SerializerMethodField('get_user')
class Meta:
model = Item
fields = (
'id',
'name',
'current_user',
)
def get_user(self, obj):
request = self.context
return request.user # <- here is current your user
In GET method:
Add context={'user': request.user} in the View class:
class ContentView(generics.ListAPIView):
def get(self, request, format=None):
content_list = <Respective-Model>.objects.all()
serializer = ContentSerializer(content_list, many=True,
context={'user': request.user})
Get it in the Serializer class method:
class ContentSerializer(serializers.ModelSerializer):
rate = serializers.SerializerMethodField()
def get_rate(self, instance):
user = self.context.get("user")
...
...
In POST method:
Follow other answers (e.g. Max's answer).
You need a small edit in your serializer:
class PostSerializer(serializers.ModelSerializer):
class Meta:
model = Post
def save(self):
user = self.context['request'].user
title = self.validated_data['title']
article = self.validated_data['article']
Here is an example, using Model mixing viewsets. In create method you can find the proper way of calling the serializer. get_serializer method fills the context dictionary properly. If you need to use a different serializer then defined on the viewset, see the update method on how to initiate the serializer with context dictionary, which also passes the request object to serializer.
class SignupViewSet(mixins.UpdateModelMixin, mixins.CreateModelMixin, viewsets.GenericViewSet):
http_method_names = ["put", "post"]
serializer_class = PostSerializer
def create(self, request, *args, **kwargs):
serializer = self.get_serializer(data=request.data)
serializer.is_valid(raise_exception=True)
self.perform_create(serializer)
headers = self.get_success_headers(serializer.data)
return Response(serializer.data, status=status.HTTP_201_CREATED, headers=headers)
def update(self, request, *args, **kwargs):
partial = kwargs.pop('partial', False)
instance = self.get_object()
kwargs['context'] = self.get_serializer_context()
serializer = PostSerializer(instance, data=request.data, partial=partial, **kwargs)
serializer.is_valid(raise_exception=True)
self.perform_update(serializer)
return Response(serializer.data)
The solution can be simple for this however I tried accessing using self.contenxt['request'].user but not working in the serializer.
If you're using DRF obviously login via token is the only source or maybe others that's debatable.
Moving toward a solution.
Pass the request.user instance while creating serializer.create
views.py
if serializer.is_valid():
watch = serializer.create(serializer.data, request.user)
serializer.py
def create(self, validated_data, usr):
return Watch.objects.create(user=usr, movie=movie_obj, action=validated_data['action'])
If you are using generic views and you want to inject current user at the point of saving the instance then you can override perform_create or perform_update:
def perform_create(self, serializer):
serializer.save(user=self.request.user)
user will be added as an attribute to kwargs and you can access it through validated_data in serializer
user = validated_data['user']
drf srz page
in my project it worked my user field was read only so i needed to get
user id in the create method
class CommentSerializer(serializers.ModelSerializer):
comment_replis = RecursiveField(many=True, read_only=True)
user = UserSerializer(read_only=True)
class Meta:
model = PostComment
fields = ('_all_')
def create(self, validated_data):
post = PostComment.objects.create(**validated_data)
print(self._dict_['_kwargs']['data']["user"]) # geting #request.data["user"] # <- mian code
post.user=User.objects.get(id=self._dict_['_kwargs']['data']["user"])
return post
in my project i tried this way and it work
The best way to get current user inside serializer is like this.
AnySerializer(data={
'example_id': id
}, context={'request': request})
This has to be written in views.py
And now in Serializer.py part
user = serializers.CharField(default=serializers.CurrentUserDefault())
This "user" must be your field in Model as any relation like foreign key