I am using Django Rest Framework with React for the front.
I want to post Note linked to a ForeignKey User.
models.Note
class Note(models.Model):
user = models.OneToOneField(User, on_delete=models.CASCADE)
content = models.TextField(blank=True, default='')
serializers.NoteSerializer
class NoteSerializer(serializers.ModelSerializer):
user = serializers.PrimaryKeyRelatedField(queryset=User.objects.all())
class Meta:
model = Note
fields = ('user', 'content')
When I post {user: 1, content: "test"}, I get the following error message:
UNIQUE constraint failed: app_note.user_id
How can I link the new Note to an existing user, posting the user.id?
I think my current code is trying to create a new User Instance...
You are using OneToOneField in Note model. That means a user can have only one note.
use ForeignKey instead to have many notes for single user.
Related
I'm trying to show the primary key in the examples section of Swagger, I'm using drf-spectacular and my code looks like:
Serializers.py
class SerializerExample(serializers.ModelSerializer):
class Meta:
model = Book
fields = ('id','name')
Views.py
class BooksBulkUpdate(APIView):
#extend_schema(
request=SerializerExample(many=True),
responses={200:''},
)
def put(self, request, format=None):
with transaction.atomic():
for data in request.data:
book = Book.objects.get(pk=data['id'])
serializer = SerializerExample(book, data=data, partial=True)
if serializer.is_valid():
serializer.save()
else:
return Response(serializer.errors, status=status.HTTP_400_BAD_REQUEST)
return Response()
Only the name field is showing:
The only solution that I found was using an inline serializer which is not the ideal solution because if I update my book serializer I'd have to remember to update also this inline serializer. I wonder if there is a better way of doing this.
AFAIK swagger shows input request schema.
For example, you want to add new person and your model is
class Person(models.Model):
id = models.UUIDField(primary_key=True, default=uuid.uuid4, editable=False)
name = models.CharField(max_length=30)
So you allowed to set only name parameter
Even if you post
{
"id": "someUUID",
"name": "NAME",
}
id will be ignored and Django create it automatically by own logic (because it is read only)
But you can set id field writeable:
class SerializerExample(serializers.ModelSerializer):
id = serializers.UUIDField(write_only=True)
name = serializers.CharField(write_only=True)
class Meta:
model = Person
fields = ('id','name')
write_only=True means that field will be active when you saving new data and receiving id from request json.
In opposite read_only=True will print id field at response (if you trying get data) but ignore it when you saving new data.
So you try to describe API for data adding, and of course that is not allow to set id field in request json.
Not sure if this theory applicable to your case, but hope that will be helpful.
I have a model, 'Project'. The idea is that, a user will log in and create a project. After creating, the user will work on this project at any time. Certain details will be saved to other models where I have written custom functions for it in Serializers.py.
In order solve the idea I have, I need to retrieve the id of the current project that the user is currently working on in Serializers.py. Below is my code:
View.py
class MaterialTagExcelViewSet(FilteredModelViewSet):
queryset = MaterialTagExcel.objects.all()
serializer_class = MaterialTagExcelSerializer
permission_classes = (IsAuthenticated,)
http_method_names = ('get', 'head', 'post', 'options', 'patch')
Serializers.py
class MaterialTagExcelSerializer(BaseSerializer):
class Meta:
fields = "__all__"
model = MaterialTagExcel
def create(self, validated_data):
name = validated_data.get('name') # get current material name
if name is not None:
name_tag = MaterialTagExcel.objects.filter(name=name).first() # filter name to check if it already exists
client = self.context['request'].user.profile.client # get current client details
if name_tag is not None: # if name exists
objects = MaterialExcelClient.objects.filter(client_id=client.id, name_id=name_tag.id)
if objects.count() == 0:
material_excel_client = MaterialExcelClient(client_id=client.id, name_id=name_tag.id)
material_excel_client.save() # get current id and mat id and save to material_client_excel
return MaterialExcelClient.objects.filter(name_id=name_tag.id).order_by('-id')[0]
else:
return MaterialExcelClient.objects.filter(client_id=client.id, name_id=name_tag.id).first()
else:
MaterialTagExcel.objects.create(**validated_data)
MaterialTagExcel.objects.all() # save if material is new and does not exist
# return the id of this newly created material
obj = MaterialTagExcel.objects.filter(name=name).order_by('-id')[0]
# save the id of the newly created material and current client id into material_excel_client
material_excel_client = MaterialExcelClient(client_id=client.id, name_id=obj.id)
material_excel_client.save()
return MaterialExcelClient.objects.filter(name_id=obj.id).order_by('-id')[0]
From above serializer, I am able to get the client.id with the help of CurrentUserDefault. In my table user is related to profile and profile is related to client but not project. I tried to with a custom CurrentProjectDefault, but I didnt succeeded. I tried with many online sources to solve my problem.
Is there any way to get the id of the current object from client ?
I am apologizing in advance if the solution to my problem is very simple.
If you would need some more details, kindly write it in comment.
Thanks in advance.
Models.py
class MaterialTagExcel():
name = models.CharField(max_length=255, verbose_name='name', null=False, blank=False)
def __str__(self):
return "Material %s: %s" % (self.id, self.name)
#classmethod
def get_queryset_for_user(cls, user):
return cls.objects.all()
class Project():
client = models.ForeignKey(Client, related_name='projects', on_delete=models.PROTECT)
name = models.CharField(max_length=255)
class ToDo(BaseModel):
project = models.ForeignKey(Project, related_name='todos', on_delete=models.CASCADE)
owner_client = models.ForeignKey(Client, related_name='todos', on_delete=models.CASCADE)
You wish to retrieve the current project the user is working on. The goal of a REST API is to be stateless, which roughly means that the request contains all the necessary information to perform its action without relying on an external context.
This means that you have to provide the current project id in each of your request.
So, in your example, when you want to POST a new MaterialTagExcel, you'll have to provide the Project. You can modify your serializer like this to do so:
class MaterialTagExcelSerializer(BaseSerializer):
project = serializers.PrimaryKeyRelatedField(write_only=True, queryset=Project.objects.all())
class Meta:
fields = "__all__"
model = MaterialTagExcel
def create(self, validated_data):
name = validated_data.get('name')
project = validated_data.pop('project') # A Project object
Now, when you're doing a request, you'll have to specify the property project with the id. of the project the user has selected in the menu.
Edit: This is using django rest framework 2.3
I have a model structure that has 3 relationship "levels", one of which is many to many.
class Shipment(models.Model):
stuff...
class ShipmentItem(models.Model):
shipment = models.ForeignKey(Shipment)
assets = models.ManyToMany(ShipmentAsset)
class ShipmentAsset(models.Model)
serial_number = models.CharField(unique=True)
Using Django rest framework I want to be able to post to the "Shipment" endpoint with a payload that contains the ShipmentItems for the Shipment, and the ShipmentAssets for the ShipmentItems ideally in one request.
The serializers are as follows..
class ShipmentAssetSerializer(serializers.ModelSerializer):
class Meta:
model = ShipmentAsset
field = ('id', 'serial_number', )
class ShipmentItemSerializer(serializers.ModelSerializer):
assets = ShipmentAssetSerializer(
many=True, required=False, allow_add_remove=True,
)
class Meta:
model = ShipmentItem
fields = ('id', 'assets', )
class ShipmentSerializer(serializers.ModelSerializer):
class Meta:
model = Shipment
fields = (
'id',
)
The shipmentItem/Shipment relationship seems to work when I post to it with the assets part disabled, but when I try to post assets in the payload, It appears to be trying to create NEW assets with the posted data (I get an error regarding the unique constraint on the serial number) rather than creating a new many-to-many table object. Any idea what I'm doing wrong?
Edit: Important clarification, I'm using Django Rest Framework 2.3.13
I have a user profile class and am checking if a user exists and if not want to create that user.
Am using the filter class for userprofile so that the client can call :
http://localhost:8000/users/?email=a#b.com
and if the result is empty will create a user with the email address.
Is there a way to intercept the query result and raise an exception when its empty and handle that to create the user.
If there is a better way would like to be corrected as well.
class UserQueryFilter(django_filters.rest_framework.FilterSet):
email = django_filters.CharFilter(name="user__email")
username = django_filters.CharFilter(name="user__username")
class Meta:
model = UserProfile
fields = ['email', 'username']
class UserViewSet(viewsets.ReadOnlyModelViewSet):
queryset = UserProfile.objects.all()
serializer_class = UserSerializer
filter_class = UserQueryFilter
Any help is appreciated.
Thanks
Anand
Django Rest Framework provide a functionality that is disabled by default. Maybe it could give you another approach to resolve your problem: PUT as create
In other hand, if you really need to create the user through a GET request with a querystring, you can use a MethodFilter from django-filters, for example:
class UserFilters(FilterSet):
user = MethodFilter(action='filter_user')
class Meta:
model = User
fields = ['user']
def filter_user(self, queryset, value):
if not value:
# Here Raise Exception
else:
# Check if the user exists, if not create it
users = queryset.filter(Q(username=value) | Q(email=value))
if not users.exists:
user = User.objects.create(...)
return queryset.filter(pk=user.id)
else:
return users
Hope this can help you. I'm not pretty sure about it works in that exact way but it's the idea.
Personally, I recommend you that try to execute that tasks through a more appropriate request like POST or PUT and manage in the corresponding method.
I'm trying to create a new Topic and the category id is dynamically determined in javascript on the client side. The problem i'm having is I pass the category id and I want to lookup the correct category object, but using a model form, it checks if the category is an instance of Category before I can assign it and save it.
--model.py--
class Topic(models.Model):
category = models.ForeignKey(Category)
--form.py--
class TopicForm(ModelForm):
category = forms.IntegerField(widget=forms.HiddenInput())
class Meta:
model = Topic
fields = ('category')
--view.py--
form = TopicForm(request.POST)
if form.is_valid():
form.save(commit=False) # throws exception category is not a Category instance
form.category = Category.objects.get(pk=form.cleaned_data.get('category'))
form.save()
Use a ModelChoiceField instead of the IntegerField in your form. See the built-in fields reference
Following Oggy's suggestion, I changed it to a ModelChoiceField and now Django does all the magic behind the scenes.
category = forms.ModelChoiceField(Category.objects.all(), widget=forms.HiddenInput())
Now I hope the queryset doesn't get evaluated, since it's not necessary and there are 90,000 records. :)