I'm using a mixin on my viewset so that multiple serializers can be used accross different viewset actions and any custom actions.
I have an extra action called invoice which is just a normal update but using a different serializer. I need to perform an OPTIONS request at the endpoint to get options for a <select> element. The problem is that when I perform the request it's picking up the serializer from the default update - OrderSerializer instead of InvoiceSerializer. How can I pick up the options from the correct serializer?
class MultipleSerializerMixin:
"""
Mixin that allows for multiple serializers based on the view's
`serializer_action_classes` attribute.
ex.
serializer_action_classes = {
'list': ReadOnlyListSerializer,
'retrieve': ReadOnlyDetailSerializer,
}
"""
def get_serializer_class(self):
try:
return self.serializer_action_classes[self.action]
except (KeyError, AttributeError):
return super().get_serializer_class()
class OrderAPIViewSet(MultipleSerializerMixin,
viewsets.ModelViewSet):
queryset = Order.objects.all()
serializer_class = serializers.OrderSerializer
serializer_action_classes = {
'invoice': serializers.InvoiceSerializer,
}
#action(detail=True, methods=['put'], url_name='invoice')
def invoice(self, request, *args, **kwargs):
"""
Invoice the order and order lines.
"""
return self.update(request, *args, **kwargs)
Update:
So after inspecting the determine_actions method in metadata.SimpleMetadata it would seem that when performing an OPTIONS request view.action is metadata instead of invoice which explains why the serializer is defaulting to view.serializer_class.
One workaround is to create an extra action as a schema endpoint that could be accessed via a GET request that manually sets the action to invoice.
#action(detail=True, methods=['get', 'put'])
def invoice_schema(self, request, *args, **kwargs):
self.action = 'invoice'
data = self.metadata_class().determine_metadata(request, self)
return Response(data, status=status.HTTP_200_OK)
A more DRY solution if you have multiple actions that use different serializers would be to override the view's options method and set the action from the query parameters. This could be added to MultipleSerializerMixin to make it the default behaviour for all views that use this mixin.
def options(self, request, *args, **kwargs):
self.action = request.query_params.get('action')
return super().options(request, *args, **kwargs)
Override get_serializer_class method is enough and OPTIONS request will detect which serializer to use :
def get_serializer_class(self):
if self.request.method == 'GET':
return ReadOnlyShopSerializer
return ShopSerializer
Related
I'm using GenericAPIView with the CreateModelMixin to create a model instance. I need my serializer to add additional fields that aren't defined by the user. My Serializer.create method is already set up for this, but I don't know how to pass fields through to the CreateModelMixin.create method. Here's a minimal version of what I have:
class Foo(mixins.CreateModelMixin, generics.GenericAPIView):
permission_classes = [IsAuthenticated]
def get_serializer_class(self):
return FooSerializer
def post(self, request):
return self.create(
request, requester=request.user # Additional field
)
This doesn't work - the requester field isn't passed to FooSerializer.save, so FooSerializer throws an error when it attempts to access requester in FooSerializer.create. Before, I was using APIView and calling the serializer directly, so I could simply:
serializer = FooSerializer(data=request.data)
if serializer.is_valid():
foo = serializer.save(requester=request.user)
Is there any way to achieve this with the GenericAPIView? I want to embrace DRF's DRY-ness and avoid calling serializers in every endpoint method.
Instead of overriding create method you can override perform_create. Also you may need to define post method:
class Foo(mixins.CreateModelMixin, generics.GenericAPIView):
permission_classes = [IsAuthenticated]
def get_serializer_class(self):
return FooSerializer
def post(self, request, *args, **kwargs):
return self.create(request, *args, **kwargs)
def perform_create(self, serializer):
serializer.save(requester=self.request.user)
I am trying to make serializer class dynamic, but its not working. I have a default serializer class where as a dynamic serializer class for different actions. Here it is my modelviewset.
My view:
class ClassView(viewsets.ModelViewSet):
queryset = Class.objects.all()
serializer_class = ClassSerializer
serializer_action_classes = {
'put': AddStudentstoClassSerializer,
}
def get_serializer_class(self):
"""
returns a serializer class based on the http method
"""
try:
return self.serializer_action_classes[self.action]
except (KeyError, AttributeError):
print("iam ClassSerializer")
return super(ClassView, self).get_serializer_class()
My function inside the same modelviewset above
#action(detail=True, methods=['put'])
def add_remove_students(self, request, *args, **kwargs):
................
MY url is as below:
urlpatterns = [
path("class/<int:pk>/<slug:slug>/",views.ClassView.as_view({"put": "add_remove_students"}),
),
]
Here in the above code snippet, I try to get AddStudentstoClassSerializer inside the add_remove_students function but it is not working. As we can see the print("iam ClassSerializer") code is working, however what i wanted or AddStudentstoClassSerializer.
First of all your serializer_action_classes dictionary should look like this:
serializer_action_classes = {
'add_remove_students': AddStudentstoClassSerializer,
}
because self.action return name of the action, not the method name. What you mean to use is self.request.method attribute which shoud return PUT in this case..
But there's better way to achieve your goal:
#action(detail=True, methods=['put'], serializer_class=AddStudentstoClassSerializer)
def add_remove_students(self, request, *args, **kwargs):
action decorators can ovveride used serializer_class by themselves.
I have a list of data coming in a request, and after filtering taken out data that needs creation, I'm passing it to the serializer create method, but I'm getting this error:
AssertionError: The `.create()` method does not support writable nested fields by default.
Write an explicit `.create()` method for serializer `apps.some_app.serializers.SomeSerializer`, or set `read_only=True` on nested serializer fields.
My view looks like this:
class MyViewSet(ModelViewSet):
# Other functions in ModelViewset
#action(methods=['post'], url_path='publish', url_name='publish', detail=False)
def publish_data(self, request, *args, **kwargs):
new_data = util_to_filter_data(request.data)
serializer = self.serializer_class(data=new_data, many=True)
if serializer.is_valid(raise_exception=True):
serializer.create(serializer.validated_data)
return Response()
I understood the error, that I am passing nested fileds in the create method. But, when I am directly calling my Viewset with single POST request, it is created successfully, even though it too contains nested fields.
What am I doing wrong here?
Here's my serializer:
class SomeSerializer(ModelSerializer):
# fields
def create(self, validated_data):
print("in create")
return super().create(validated_data)
def save(self, **kwargs):
print("in save")
my_nested_field = self.validated_data.pop('my_nested_field', '')
# Do some operations on this field, and other nested fields
obj = None
with transaction.atomic():
obj = super().save(kwargs)
# Save nested fields
return obj
Here in create is being seen in terminal, but not in save.
you should not use serializer create method directly; instead use save. Also no need to check serializer.is_valid with if when raise_exception=True, if it is not valid it will return the exception
Try following.
class MyViewSet(ModelViewSet):
# Other functions in ModelViewset
#action(methods=['post'], url_path='publish', url_name='publish', detail=False)
def publish_data(self, request, *args, **kwargs):
new_data = util_to_filter_data(request.data)
serializer = self.serializer_class(data=new_data, many=True)
serializer.is_valid(raise_exception=True)
serializer.save()
return Response(serializer.data)
I am not very experience with Django REST framework and have been trying out many things but can not make my PATCH request work.
I have a Model serializer. This is the same one I use to add a new entry and ideally I Would want to re-use when I update an entry.
class TimeSerializer(serializers.ModelSerializer):
class Meta:
model = TimeEntry
fields = ('id', 'project', 'amount', 'description', 'date')
def __init__(self, user, *args, **kwargs):
# Don't pass the 'fields' arg up to the superclass
super(TimeSerializer, self).__init__(*args, **kwargs)
self.user = user
def validate_project(self, attrs, source):
"""
Check that the project is correct
"""
.....
def validate_amount(self, attrs, source):
"""
Check the amount in valid
"""
.....
I tried to use a class based view :
class UserViewSet(generics.UpdateAPIView):
"""
API endpoint that allows timeentries to be edited.
"""
queryset = TimeEntry.objects.all()
serializer_class = TimeSerializer
My urls are:
url(r'^api/edit/(?P<pk>\d+)/$', UserViewSet.as_view(), name='timeentry_api_edit'),
My JS call is:
var putData = { 'id': '51', 'description': "new desc" }
$.ajax({
url: '/en/hours/api/edit/' + id + '/',
type: "PATCH",
data: putData,
success: function(data, textStatus, jqXHR) {
// ....
}
}
In this case I would have wanted my description to be updated, but I get errors that the fields are required(for 'project'and all the rest). The validation fails. If add to the AJAX call all the fields it still fails when it haves to retrieve the 'project'.
I tried also to make my own view:
#api_view(['PATCH'])
#permission_classes([permissions.IsAuthenticated])
def edit_time(request):
if request.method == 'PATCH':
serializer = TimeSerializer(request.user, data=request.DATA, partial=True)
if serializer.is_valid():
time_entry = serializer.save()
return Response(status=status.HTTP_201_CREATED)
return Response(status=status.HTTP_400_BAD_REQUEST)
This did not work for partial update for the same reason(the validation for the fields were failing) and it did not work even if I've sent all the fields. It creates a new entry instead of editing the existing one.
I would like to re-use the same serializer and validations, but I am open to any other suggestions.
Also, if someone has a piece of working code (ajax code-> api view-> serializer) would be great.
class DetailView(APIView):
def get_object(self, pk):
return TestModel.objects.get(pk=pk)
def patch(self, request, pk):
testmodel_object = self.get_object(pk)
serializer = TestModelSerializer(testmodel_object, data=request.data, partial=True) # set partial=True to update a data partially
if serializer.is_valid():
serializer.save()
return JsonResponse(code=201, data=serializer.data)
return JsonResponse(code=400, data="wrong parameters")
Documentation
You do not need to write the partial_update or overwrite the update method. Just use the patch method.
Make sure that you have "PATCH" in http_method_names. Alternatively you can write it like this:
#property
def allowed_methods(self):
"""
Return the list of allowed HTTP methods, uppercased.
"""
self.http_method_names.append("patch")
return [method.upper() for method in self.http_method_names
if hasattr(self, method)]
As stated in documentation:
By default, serializers must be passed values for all required fields or they will raise validation errors. You can use the partial argument in order to allow partial updates.
Override update method in your view:
def update(self, request, *args, **kwargs):
instance = self.get_object()
serializer = TimeSerializer(instance, data=request.data, partial=True)
serializer.is_valid(raise_exception=True)
serializer.save(customer_id=customer, **serializer.validated_data)
return Response(serializer.validated_data)
Or just override method partial_update in your view:
def partial_update(self, request, *args, **kwargs):
kwargs['partial'] = True
return self.update(request, *args, **kwargs)
Serializer calls update method of ModelSerializer(see sources):
def update(self, instance, validated_data):
raise_errors_on_nested_writes('update', self, validated_data)
# Simply set each attribute on the instance, and then save it.
# Note that unlike `.create()` we don't need to treat many-to-many
# relationships as being a special case. During updates we already
# have an instance pk for the relationships to be associated with.
for attr, value in validated_data.items():
setattr(instance, attr, value)
instance.save()
return instance
Update pushes the validated_data values to the given instance. Note that update should not assume all the fields are available. This helps to deal with partial updates (PATCH requests).
The patch method is worked for me using viewset in DRF. I'm changing you code:
class UserViewSet(viewsets.ModelViewSet):
queryset = TimeEntry.objects.all()
serializer_class = TimeSerializer
def perform_update(self, serializer):
user_instance = serializer.instance
request = self.request
serializer.save(**modified_attrs)
return Response(status=status.HTTP_200_OK)
Use ModelViewSet instead and override perform_update method from UpdateModelMixin
class UserViewSet(viewsets.ModelViewSet):
queryset = TimeEntry.objects.all()
serializer_class = TimeSerializer
def perform_update(self, serializer):
serializer.save()
# you may also do additional things here
# e.g.: signal other components about this update
That's it. Don't return anything in this method. UpdateModelMixin has implemented update method to return updated data as response for you and also clears out _prefetched_objects_cache. See the source code here.
I ran into this issues as well, I solved it redefining the get_serializer_method and adding custom logic to handle the partial update. Python 3
class ViewSet(viewsets.ModelViewSet):
def get_serializer_class(self):
if self.action == "partial_update":
return PartialUpdateSerializer
Note: you may have to override the partial_update function on the serializer. Like so:
class PartialUpdateSerializer(serializers.Serializer):
def partial_update(self, instance, validated_data):
*custom logic*
return super().update(instance, validated_data)
Another posiblity is to make the request by URL. For example, I have a model like this
class Author(models.Model):
FirstName = models.CharField(max_length=70)
MiddleName = models.CharField(max_length=70)
LastName = models.CharField(max_length=70)
Gender = models.CharField(max_length=1, choices = GENDERS)
user = models.ForeignKey(User, default = 1, on_delete = models.CASCADE, related_name='author_user')
IsActive = models.BooleanField(default=True)
class Meta:
ordering = ['LastName']
And a view like this
class Author(viewsets.ModelViewSet):
queryset = Author.objects.all()
serializer_class = AuthorSerializer
So can enter http://127.0.0.1:8000/author/ to get or post authors. If I want to make a PATCH request you can point to http://127.0.0.1:8000/author/ID_AUTHOR from your client. For example in angular2, you can have something like this
patchRequest(item: any): Observable<Author> {
return this.http.patch('http://127.0.0.1:8000/author/1', item);
}
It suppose you have configured your CORS and you have the same model in back and front.
Hope it can be usefull.
I am trying to build an API view, to handle user management using django rest framework version 2.3.10 with django 1.6. I tried to build a ModelViewSet which based on the URL pk value it would return either current user or public user.
I tried to add a dispatch function which will assigned pk to current user, but it seems like this function is running too soon that its always seeing the user as anonymous
class UserViewSet(viewsets.ModelViewSet):
"""
"""
queryset = User.objects.all()
serializer_class = UserSerializer
permission_classes = (IsOwnerOrCreateOnly, )
def dispatch(self, request, *args, **kwargs):
if kwargs.get('pk') == 'current' and not request.user.is_anonymous():
kwargs['pk'] = request.user.pk
resp = super(CurrentUserViewSet, self).dispatch(request, *args, **kwargs)
return resp
I tried to do the below, which works
class UserViewSet(viewsets.ModelViewSet):
"""
"""
queryset = User.objects.all()
serializer_class = UserSerializer
permission_classes = (IsOwnerOrCreateOnly, )
def retrieve(self, request, *args, **kwargs):
if self.kwargs.get('pk') == u'current' and not request.user.is_anonymous():
self.kwargs['pk'] = request.user.pk
return super(CurrentUserViewSet, self).retrieve(request, *args, **kwargs)
but, I don't want to override each and every function on several ModelViewSet classes I have, so, is there a way to use something similar to the dispatcher whereby I can check if the pk is equal to "current" and then assign current user to it?
Another question, how can I change the returned fields programmatically? for example when querying current user I want to include the first and last name from the user model, but when querying by primary key, I want first and last name to not return as response? any suggestions on how todo that?
I got the same problem I solved it by using method "initial" instead of "dispatch"
class UserViewSet(viewsets.ModelViewSet):
queryset = User.objects.all()
serializer_class = UserSerializer
permission_classes = (IsOwnerOrCreateOnly, )
def initial(self, request, *args, **kwargs):
# logic - code #
if kwargs.get('pk') == 'current' and not request.user.is_anonymous():
kwargs['pk'] = request.user.pk
# end #
resp = super(CurrentUserViewSet, self).initial(request, *args, **kwargs)
return resp
see " dispatch "
method in https://github.com/tomchristie/django-rest-framework/blob/master/rest_framework/views.py
for better understanding.
Override viewsets.ModelViewSet class with your pk check implementation and use that new class, something like this:
class GenericUserViewSet(viewsets.ModelViewSet):
def retrieve(self, request, *args, **kwargs):
if self.kwargs.get('pk') == u'current' and not request.user.is_anonymous():
self.kwargs['pk'] = request.user.pk
return super(CurrentUserViewSet, self).retrieve(request, *args, **kwargs)
class UserViewSet(GenericUserViewSet):
queryset = User.objects.all()
serializer_class = UserSerializer
permission_classes = (IsOwnerOrCreateOnly, )
And for the second question, perhaps creating two serializers (public and current) and changing serializer_class to either one of them in init of GenericUserViewSet may do the trick, I haven't tested this but it's an idea:
class GenericUserViewSet(viewsets.ModelViewSet):
def __init__(self, *args, **kwargs):
if self.kwargs.get('pk') == u'current' and not request.user.is_anonymous():
self.serializer_class = UserSerializer
else:
self.serializer_class = PublicUserSerializer
super(GenericUserViewSet, self).__init__(*args, **kwargs)
I'm assuming that you want to save the current user to your DB model, yes?
If so this should be fairly easy to fix, just add this method to your views:
def pre_save(self, obj):
obj.user = self.request.user
This will execute just before the model is saved. I use this all the time and it works great.
The other thing you can do is write a mixin class in a generic way that does want you want then inherit it in each of the views you need it in. Assuming that is that you have a solution that works, but just don't want to mimic you code all over the place.