I am checking in serializer if product exists in cart or not and I am using this
class ProductSerializer(serializers.ModelSerializer):
in_cart = serializers.SerializerMethodField()
class Meta:
model = Product
fields = ['id', 'in_cart']
def get_in_cart(self, obj):
user = self.context['request'].user
if user.is_authenticated:
added_to_cart = Cart.objects.filter(user=user, product_id=obj.id).exists()
return added_to_cart
else:
return False
It works fine but I cannot add product to the cart because of that request
my cart model like this
class Cart(models.Model):
user = models.ForeignKey(User, on_delete=models.CASCADE, null=True)
product = models.ForeignKey(Product, on_delete=models.CASCADE, null=True)
quantity = models.PositiveIntegerField()
def __str__(self):
return f'{self.user} cart item'
class ItemsListView(generics.ListAPIView):
queryset = Product.objects.all()
serializer_class = ProductSerializer
When I post product id to add cart it throws this error
user = self.context['request'].user KeyError: 'request'
I need to make both work but adding item to cart is being problem.
How can I solve this? Thank you beforehand!
You need to pass the request to the context before usage. So the calling of serializer should look like this:
ProductSerializer(product, context={'request': request})
With ListAPIView class you don't even need this, because by default it would be available in the serializer due to the default implementation of get_serializer_context method:
def get_serializer_context(self):
"""
Extra context provided to the serializer class.
"""
return {
'request': self.request,
'format': self.format_kwarg,
'view': self
}
Although you could override it if needed. Also, take a note that serializer_class accepts a callable object, it should be serializer_class = ProductSerializer.
I have had the same problem while using nested serializers. As mentioned above, you just can pass self.context['request'] to the context of nested serializer:
'author': GETUserSerializer(
recipe.author,
context={'request': self.context['request']}
).data,
Related
I have Contact model to list the followers of an User object, I try to filter the contacts of a User but I still could not manage get a correct queryset. My Contact model is simple with two ForeignKey:
class Contact(models.Model):
user_from = models.ForeignKey(User,related_name='rel_from_set', on_delete=models.CASCADE,)
user_to = models.ForeignKey(User,related_name='rel_to_set', on_delete=models.CASCADE,)
def __str__(self):
return '{} follow {}'.format(self.user_from, self.user_to)
I have created serializers for User and Contact:
##Contact Serializer
class ContactsSerializer(serializers.ModelSerializer):
user_from = serializers.StringRelatedField(read_only=True)
user_to = serializers.StringRelatedField(read_only=True)
class Meta:
model = Contact
fields = ["user_from", "user_to"]
##UserSerializer
class UserInformationSerializer(serializers.ModelSerializer):
followers = ContactsSerializer(many=True, read_only=True)
class Meta:
model = User
fields = ['first_name', 'last_name', 'followers']
And try to make a query through views:
class FollowerListView(APIView):
queryset = Contact.objects.all()
serializer_class = ContactsSerializer
lookup_field = "username"
def get(self, request, format=None, slug=None):
kwarg_username = self.kwargs.get("slug")
user = User.objects.filter(is_active=1).filter(username=kwarg_username)
print(user.username)
contacts = Contact.objects.filter(user_to=user.id)
serializer = ContactsSerializer(contacts)
return Response(serializer.data)
Now I get error message:
AttributeError at /api/member/ytsejam/followers/
'QuerySet' object has no attribute 'username'
print(user.username)
If i try print(user) I can see the user an Object.
Can you guide me how to correct?
Thanks
filter will always return a queryset. If you expect to retrieve one single item, use get.
So that it looks like that:
def get(self, request, format=None, slug=None):
kwarg_username = self.kwargs.get("slug")
user = User.objects.filter(is_active=1).get(username=kwarg_username)
print(user.username)
contacts = Contact.objects.filter(user_to=user.id)
serializer = ContactsSerializer(contacts)
return Response(serializer.data)
You could, of course, do this on one take:
User.objects.get(is_active=1, username=kwarg_username)
But beware, if there are two rows in your model that would satisfy this call, Django will throw an error. Best make sure that the username has a unique constraint.
I am trying to perform a POST request to create an article and I am getting this error Request failed with status code 400 Bad Request: /api/articles/create/.
An article needs 3 attributes to be created:
(1) title
(2) body
(3) author (the current user)
The router works fine since the POST request goes into the post method of the ArticleCreateView class. But I'm guessing that serializer.is_valid() is returning False for some reason.
Also print(request.data) returns {'title': 'hello', 'body': 'stuff'}
Another mystery about Django is, how does the serializer know if I want to get, create or update something? In all the examples I've seen, the serializer magically seems to know this.
class ArticleCreateView(CreateAPIView):
permission_classes = [IsAuthenticated]
def post(self, request):
serializer = ArticleSerializer(data=request.data)
if serializer.is_valid():
serializer.save()
return Response(serializer.data)
return Response(serializer.errors)
class ArticleSerializer(serializers.ModelSerializer):
class Meta:
model = Article
fields = '__all__'
def create(self, validated_data):
author = self.context['request'].user
title = validated_data.get('title')
body = validated_data.get('body')
return Article.objects.create(author=author, title=title, body=body)
class Article(models.Model):
author = models.ForeignKey(settings.AUTH_USER_MODEL, on_delete=models.CASCADE)
title = models.CharField(max_length=100)
body = models.TextField(max_length=100)
date_updated = models.DateTimeField(auto_now=True)
date_created = models.DateTimeField(auto_now_add=True)
According to your serializer, the validation process needs author details, which is not passing through POST payload.
So, make the author field in the serializer a not required field by adding required=False or use a ReadOnlyField() or specify read_only_fields in Meta class. Also pass context data as #nishant mentioned
# views.py
class ArticleCreateView(CreateAPIView):
permission_classes = [IsAuthenticated]
def post(self, request):
serializer = ArticleSerializer(data=request.data, context={"request": request}) # change here
if serializer.is_valid():
serializer.save()
return Response(serializer.data)
return Response(serializer.errors)
# serializer.py
class ArticleSerializer(serializers.ModelSerializer):
class Meta:
model = Article
fields = '__all__'
read_only_fields = ('author',)
def create(self, validated_data):
author = self.context['request'].user
title = validated_data.get('title')
body = validated_data.get('body')
return Article.objects.create(author=author, title=title, body=body)
add this
serializer = ArticleSerializer(data=request.data, context={'request':request})
I am using the django rest framework and I have a very simple model of Posts for a particular user which I have serialised in the following manner.
Serializers.py
class PostSerializer(serializers.HyperlinkedModelSerializer):
image = serializers.ImageField(max_length=None, use_url=True)
question = serializers.CharField(required=False)
ayes = serializers.CharField(required=False)
nays = serializers.CharField(required=False)
neutrals = serializers.CharField(required=False)
class Meta:
model = Posts
fields = ('user','question', 'image','ayes', 'nays', 'neutrals')
My models.py is as follows
class Posts(models.Model):
user = models.ForeignKey(User, on_delete=models.CASCADE)
created = models.DateTimeField(auto_now_add=True)
question = models.TextField(max_length=500, blank=True)
image = models.ImageField('optionalImage', upload_to='images/posts/', default='/images/posts/blank.png')
ayes = models.TextField(max_length=200, default=0)
nays = models.TextField(max_length=200, default=0)
neutrals = models.TextField(max_length=200, default=0)
When I tried posting to this I kept getting NOT NULL Integrity constraint error of user_id. Hence I added context={'request': request}) to the serializer which ends up giving me the following error:
Could not resolve URL for hyperlinked relationship using view name "user-detail". You may have failed to include the related model in your API, or incorrectly configured the lookup_field attribute on this field.
My views.py is as follows:
views.py
#permission_classes((IsAuthenticated, ))
class PostsView(generics.ListCreateAPIView):
queryset = Posts.objects.all()
serializer_class = PostSerializer
def get(self, request, format=None):
snippets = Posts.objects.filter(pk=request.user.id)
serializer = PostSerializer(snippets, many=True,context={'request': request})
return Response(serializer.data)
def post(self, request, format=None):
posts = PostSerializer(data=request.data,context={'request': request})
if posts.is_valid():
posts.save()
return Response("YOLO", status=status.HTTP_201_CREATED)
else:
return Response(posts.errors, status=status.HTTP_400_BAD_REQUEST)
All other fields of mine have posted correctly when I set default=0 in my model for user. I am unable to submit the foreign key user which needs to be saved on every post. What am I doing wrong here? Am I following the correct method?
Since you don't want to send your user, you should remove it from the serializer's field.
Next, you want to set the post's user to the current user. To achieve that, you want to pass the request.user to the serializer's data by changing the save method to:
posts.save(user=request.user)
It's explained in the documentation and in the tutorial
I have an Instructor model, which has a many to many field to a Client model. (Instructor.clients)
The model:
class InstructorProfile(models.Model):
'''Instructor specific profile attributes
'''
# Fields
office_number = models.CharField(max_length=30, blank=True, null=True)
location = models.CharField(max_length=30)
last_updated = models.DateTimeField(auto_now=True, editable=False)
# Relationship Fields
user = models.OneToOneField(settings.AUTH_USER_MODEL,
related_name="instructor_profile",
on_delete=models.CASCADE)
clients = models.ManyToManyField('ClientProfile', blank=True)
My serializer is currently:
class InstructorProfileSerializer(serializers.ModelSerializer):
class Meta:
model = models.InstructorProfile
fields = '__all__'
And viewset:
class InstructorProfileViewSet(viewsets.ModelViewSet):
"""ViewSet for the InstructorProfile class"""
queryset = models.InstructorProfile.objects.all()
serializer_class = serializers.InstructorProfileSerializer
permission_classes = [permissions.IsAuthenticated]
I'd like to prevent access to the clients field to everyone except the user which Instructor belongs to (available in the Instructor.user model field).
How can I achieve this?
Add this to your InstructorProfileViewSet:
...
def get_queryset(self):
if hasattr(self.request.user, 'instructor_profile'):
return models.InstructorProfile.objects.filter(user=self.request.user)
else:
return models.InstructorProfile.objects.none()
... if I guessed your InstructorProfile model correctly.
One way to do this is to change the list method to set the client=None where needed. This way you would preserve the response structure. It would be something like this:
def list(self, request, *args, **kwargs):
queryset = self.filter_queryset(self.get_queryset())
page = self.paginate_queryset(queryset)
if page is not None:
serializer = self.get_serializer(page, many=True)
return self.get_paginated_response(serializer.data)
serializer = self.get_serializer(queryset, many=True)
for i in serializer.data:
if i['user'] != request.user.pk:
i['client'] = None
return Response(serializer.data)
I am using DRF to expose some API endpoints.
# models.py
class Project(models.Model):
...
assigned_to = models.ManyToManyField(
User, default=None, blank=True, null=True
)
# serializers.py
class ProjectSerializer(serializers.ModelSerializer):
assigned_to = serializers.PrimaryKeyRelatedField(
queryset=User.objects.all(), required=False, many=True)
class Meta:
model = Project
fields = ('id', 'title', 'created_by', 'assigned_to')
# view.py
class ProjectList(generics.ListCreateAPIView):
mode = Project
serializer_class = ProjectSerializer
filter_fields = ('title',)
def post(self, request, format=None):
# get a list of user.id of assigned_to users
assigned_to = [x.get('id') for x in request.DATA.get('assigned_to')]
# create a new project serilaizer
serializer = ProjectSerializer(data={
"title": request.DATA.get('title'),
"created_by": request.user.pk,
"assigned_to": assigned_to,
})
if serializer.is_valid():
serializer.save()
else:
return Response(serializer.errors,
status=status.HTTP_400_BAD_REQUEST)
return Response(serializer.data, status=status.HTTP_201_CREATED)
This all works fine, and I can POST a list of ids for the assigned to field. However, to make this function I had to use PrimaryKeyRelatedField instead of RelatedField. This means that when I do a GET then I only receive the primary keys of the user in the assigned_to field. Is there some way to maintain the current behavior for POST but return the serialized User details for the assigned_to field?
I recently solved this with a subclassed PrimaryKeyRelatedField() which uses the id for input to set the value, but returns a nested value using serializers. Now this may not be 100% what was requested here. The POST, PUT, and PATCH responses will also include the nested representation whereas the question does specify that POST behave exactly as it does with a PrimaryKeyRelatedField.
https://gist.github.com/jmichalicek/f841110a9aa6dbb6f781
class PrimaryKeyInObjectOutRelatedField(PrimaryKeyRelatedField):
"""
Django Rest Framework RelatedField which takes the primary key as input to allow setting relations,
but takes an optional `output_serializer_class` parameter, which if specified, will be used to
serialize the data in responses.
Usage:
class MyModelSerializer(serializers.ModelSerializer):
related_model = PrimaryKeyInObjectOutRelatedField(
queryset=MyOtherModel.objects.all(), output_serializer_class=MyOtherModelSerializer)
class Meta:
model = MyModel
fields = ('related_model', 'id', 'foo', 'bar')
"""
def __init__(self, **kwargs):
self._output_serializer_class = kwargs.pop('output_serializer_class', None)
super(PrimaryKeyInObjectOutRelatedField, self).__init__(**kwargs)
def use_pk_only_optimization(self):
return not bool(self._output_serializer_class)
def to_representation(self, obj):
if self._output_serializer_class:
data = self._output_serializer_class(obj).data
else:
data = super(PrimaryKeyInObjectOutRelatedField, self).to_representation(obj)
return data
You'll need to use a different serializer for POST and GET in that case.
Take a look into overriding the get_serializer_class() method on the view, and switching the serializer that's returned depending on self.request.method.