when I try to sort my id in my serializers it gives me an error : AttributeError: 'int' object has no attribute 'all'.
Here is the code of my serializers :
class DatasetPidTrierSerializer(serializers.HyperlinkedModelSerializer):
id = serializers.SerializerMethodField()
class Meta:
model = Dataset
fields = ['id']
def get_id(self, instance):
songs = instance.id.all().order_by('id')
return DatasetPidSerializer(songs, many=True).data
Here is the beginning of it : model Dataset
thank you for your help
First, you don't need to set id field in Dataset model. Django will do that automatically for you. You can define just two fields pid and iddatta_resolution.
class Dataset(models.Model):
pid = models.ManyToManyField(
...
)
iddata_resolution = models.ForeignKey(
...
)
And then in the serializer, you don't need to define id field. Because the default order will be id field automatically by Django.
class DatasetPidTrierSerializer(serializers.HyperlinkedModelSerializer):
class Meta:
model = Dataset
fields = ['id']
Related
I'm now using DRF as a backend of my project.
i have product model like this
class product(models.Model):
product_name = models.CharField(max_length=160)
i have category model like this
class category(models.Model):
category_name = models.CharField(max_length=60)
category_icon = models.ImageField(upload_to='category)
because 1 product can have multiple category and a lot of image I create
class product_category(models.Model):
product = models.ForeignKey(product, on_delete=models.CASCADE, related_name='product_collections')
category = models.ForeignKey(category, on_delete=models.CASCADE, related_name='category_collections')
and the last model
class product_image(models.Model):
product = models.ForeignKey(product, on_delete=models.CASCADE,related_name='image_collections')
product_img = models.ImageField(upload_to='product')
Now I have Serializer like this
class ProductCategorySerializer(serializers.ModelSerializer):
category_name = serializers.CharField(source='category.category_name')
class Meta:
model = product_category
fields = ('product_id','category_id','category_name')
class ProductImageSerializer(serializers.ModelSerializer):
class Meta:
model = product_images
fields = ('product_img',)
class ProductSerializer(serializers.ModelSerializer):
category_collections = CategoryProductSerializers(many=True)
image_collections = ProductImageSerializer(many=True)
class Meta:
model = product
fields = ('id','product_name','image_collections','category_collections')
From that serializer DRF will return
Error like this
Got AttributeError when attempting to get a value for field category_collections on serializer ProductSerializer.
The serializer field might be named incorrectly and not match any attribute or key on the product instance.
but if i remove that category_collections field like this
class ProductSerializer(serializers.ModelSerializer):
# category_collections = CategoryProductSerializers(many=True)
image_collections = ProductImageSerializer(many=True)
class Meta:
model = product
fields = ('id','product_name','image_collections')
Everything is going fine, whats wrong with that categories collection, is my eye not seeing the mistake ?
I am trying to use Django with mongoengine to make an API.
So far I can get the objects and delete them. but when I want to post some data. Lets say student + course it is giving an error:
type object 'Course' has no attribute 'objects'
Models en ..
#Model.py
class Course(EmbeddedDocument):
course_name = StringField(max_length=200)
course_fee = StringField(max_length=200)
class Student(Document):
student_name = StringField(max_length=200)
student_contactperson = StringField(max_length=200)
student_adress = StringField(max_length=200)
courses = ListField(EmbeddedDocumentField(Course))
#Serializers.py
class CourseSerializer(EmbeddedDocumentSerializer):
class Meta:
model = Course
fields = ('course_name','course_fee')
class StudentSerializer(DocumentSerializer):
courses = CourseSerializer(many=True)
class Meta:
model = Student
fields = ('student_name','student_contactperson','student_adress','courses')
depth = 2
def create(self, validated_data):
course_data = validated_data.pop('courses')
student = Student.objects.create(**validated_data)
Course.objects.create(student=student, **course_data)
return student
#Views.py
class StudentViewSet(meviewsets.ModelViewSet):
lookup_field = 'name'
queryset = Student.objects.all().order_by('-date_joined')
serializer_class = StudentSerializer
A Document represents a MongoDB document (i.e a record in a collection), a Document class is bound to a particular collection. An EmbeddedDocument represents a structure that gets nested in a Document.
So by design an EmbeddedDocument isn't attached to any collection unless you embed it inside a Document.
This means that you can't query or save an EmbeddedDocument class, you need to query/save the parent Document.
Document.objects is an entry point for querying a collection, it only exists on Document classes. You are calling Course.objects.create but Course is an EmbeddedDocument.
I believe you need to change your code to the following
class StudentSerializer(DocumentSerializer):
...
def create(self, validated_data):
course_data = validated_data.pop('courses')
course = Course(**course_data) # assuming course_data is {course_name: ..., course_fee: ...}
return Student.objects.create(courses=[course], **validated_data)
Store has a foreign key to SimilarStore. Normally, there is about a hundred of similar stores in similarstore_set. Is there a way to limit the number of similar stores in similarstore_set when I make API with Django REST Framework?
serializer.py
class SimilarStoreSerializer(ModelSerializer):
class Meta:
model = SimilarStore
fields = ('domain', )
class StoreSerializer(ModelSerializer):
similarstore_set = SimilarStoreSerializer(many=True)
class Meta:
model = Store
fields = '__all__'
UPDATE
The following codes throws 'Store' object has no attribute 'similarstores_set', it actually has similarstore_set, why is it throwing the error?
class StoreSerializer(ModelSerializer):
image_set = ImageSerializer(many=True)
promotion_set = PromotionSerializer(many=True)
similar_stores = SerializerMethodField()
def get_similar_stores(self, obj):
# get 10 similar stores for this store
stores = obj.similarstores_set.all()[:10] <-- This line throws the error
return SimilarStoreSerializer(stores, many=True).data
class Meta:
model = Store
fields = '__all__'
You can use a SerializerMethodField to perform a custom lookup and limit the number of records:
class StoreSerializer(ModelSerializer):
similar_stores = serializers.SerializerMethodField()
def get_similar_stores(self, obj):
stores = obj.similarstore_set.all()[:10] # get 10 similar stores for this store
return SimilarStoreSerializer(stores, many=True).data
class Meta:
model = Store
fields = '__all__'
You could add a serializers.SerializerMethodField() for similarstore_set and define a method that would query the SimilarStore data and set similarstore_set. You could pass the number of elements you want in similarstore_set by passing context to your serializer. see https://www.django-rest-framework.org/api-guide/serializers/#including-extra-context
I have the following models:
class Contact(models.Model):
class Meta:
managed = False
db_table = 'contact'
class ContactPhone(models.Model):
contact = models.ForeignKey(Contact, on_delete = models.CASCADE)
number = models.CharField(max_length = 45)
class Meta:
managed = False
db_table = 'contact_phone'
Also, I have the following serializers:
class ContactSerializer(serializers.ModelSerializer):
server_id = serializers.IntegerField(source='id', read_only=True)
class Meta:
model = Contact
fields = '__all__'
class ContactPhoneSerializer(serializers.ModelSerializer):
class Meta:
model = ContactPhone
fields = '__all__'
Now, I have a view that insert phone numbers for an existing contact.
The input is a json that looks like this:
data = {'contact_id': 12322,
'phones':[{'number': '89120000001'}]}
The view:
def insert_contact_phone(request):
for record in request.data['phones']:
data['contact_id'] = request.data['contact_id']
serializer = ContactPhoneSerializer(data = data)
if serializer.is_valid():
serializer.save()
I end up with the following error:
RelatedObjectDoesNotExist at /contacts/edit ContactPhone has no
contact.
What am I doing wrong?
If you specify __all__ for the fields in your ContactPhoneSerializer, it does not include contact_id.
So the contact_id taken from the json input is not serialized. It is basically ignored and when you try to save and create new ContactPhone - it fails, because it does not have contact's foreign key correctly set.
But simply adding contact_id to the serializer's fields won't solve your problem.
In your view, i recommend you to set the contact instead:
data['contact'] = request.data['contact_id']
and pass this to the ContactPhoneSerializer.
I'm trying to serialize a model containing a property field that I also want to serialize.
models.py:
class MyModel(models.Model):
name = models.CharField(max_length=100)
slug = models.AutoSlugField(populate_from='name')
#property
def ext_link(self):
return "/".join([settings.EXT_BASE_URL, self.slug])
serializers.py:
class MyModelSerializer(serializers.ModelSerializer):
class Meta:
model = MyModel
fields = ('name', 'ext_link')
When trying to get to the related URL, I'm getting a serializer exception (KeyError) on the ext_link property.
How can I serialize the ext_link property?
Because it's not a model field, it needs to be added explicitly to the serializer class
class MyModelSerializer(serializers.ModelSerializer):
ext_link = serializers.Field()
class Meta:
model = MyModel
fields = ('name', 'ext_link')
as #Robert Townley's comment, this work with version 3.8.2:
class MyModelSerializer(serializers.ModelSerializer):
ext_link = serializers.ReadOnlyField()
class Meta:
model = MyModel
fields = "__all__"
The accepted answer doesn't seem to work for me, nor does the ReadOnlyField.
However, I have had success when I use a field that corresponds to the return type of my property function.
So for the example, I would do this:
class MyModelSerializer(serializers.ModelSerializer):
ext_link = serializers.CharField()
class Meta:
model = MyModel
fields = ('name', 'ext_link')
I've been able to do this with ListField, DictField, and IntegerField as well.
Another thing you might want to do is add a property that its contents are not a string. Let's say you have a model called Person and another one called Food that look like this (we assume that each food is the favorite of only one person, making it a OneToMany connection):
class Person(models.Model):
name = models.CharField(max_length=255)
#property
def favorite_foods(self):
return Food.objects.filter(person=self.pk)
class Food(models.Model):
name = models.CharField(max_length=255)
persons_favorite = models.ForeignKey(Person, on_delete=models.CASCADE)
If you want to add favorite_foods in Person's serializer all you have to do is:
class PersonSerializer(serializers.ModelSerializer):
favorite_foods = FoodSerializer(read_only=True, many=True)
class Meta:
model = Person
fields = ('name', 'favorite_foods')