In my User profile model I've included a show_email field explicitly. So, to add this feature to my API, the UserSerializer class looks like this:
class UserSerializer(serializers.ModelSerializer):
email = serializers.SerializerMethodField('show_email')
def show_email(self, user):
return user.email if user.show_email else None
class Meta:
model = django.contrib.auth.get_user_model()
fields = ("username", "first_name", "last_name", "email")
But I don't really like it. I think it would be a lot cleaner if the field email would be completely excluded from the serializer output it show_email is False, instead showing that ugly "email": null thing.
How could I do that?
You could do this in your API view by overriding the method returning the response, i.e. the "verb" of the API view. For example, in a ListAPIView you would override get():
class UserList(generics.ListAPIView):
model = django.contrib.auth.get_user_model()
serializer_class = UserSerializer
def get(self, request, *args, **kwargs):
response = super(UserList, self).get(request, *args, **kwargs)
for result in response.data['results']:
if result['email'] is None:
result.pop('email')
return response
You would probably want to add some more checking for attributes, but that's the gist of how it could be done. Also, I would add that removing fields from some results may cause issues for the consuming application if it expects them to be present for all records.
This answer comes late but for future google searches: there is an example in the documentation about Dynamically modifying fields.
So, by passing an argument to the serializer, you control whether or not a field is processed:
serializer = MyPostSerializer(posts, show_email=permissions)
and then in the init function in the serializer you can do something like:
class MyPostSerializer(serializers.ModelSerializer):
def __init__(self, *args, **kwargs):
show_email = kwargs.pop('show_email', None)
# Instantiate the superclass normally
super(DeviceSerializer, self).__init__(*args, **kwargs)
if not show_email:
self.fields.pop("show_email")
Now the show_email field will be ignored by the serializer.
You could override restore_fields method on serializer. Here in restore_fields method you can modify list of fields - serializer.fields - pop, push or modify any of the fields.
eg: Field workspace is read_only when action is not 'create'
class MyPostSerializer(ModelSerializer):
def restore_fields(self, data, files):
if (self.context.get('view').action != 'create'):
self.fields.get('workspace').read_only=True
return super(MyPostSerializer, self).restore_fields(data, files)
class Meta:
model = MyPost
fields = ('id', 'name', 'workspace')
This might be of help...
To dynamically include or exclude a field in an API request, the modification of
#stackedUser's response below should do:
class AirtimePurchaseSerializer(serializers.Serializer):
def __init__(self, *args, **kwargs):
try:
phone = kwargs['data']['res_phone_number']
except KeyError:
phone = None
# Instantiate the superclass normally
super(AirtimePurchaseSerializer, self).__init__(*args, **kwargs)
if not phone:
self.fields.pop("res_phone_number")
res_phone_number = serializers.CharField(max_length=16, allow_null=False)
Related
I'm using django-rest-framework, https://www.django-rest-framework.org/api-guide/serializers/
Is there a way to show a field only if its specified in the ?field=X param? If I try this:
class TopLevelJobSerializer(DynamicFieldsMixin, serializers.ModelSerializer):
children_job_statuses = serializers.ReadOnlyField()
class Meta:
model = TopLevelJob # This inherits from Job, which has id, name
fields = ('id', 'name')
I get AssertionError: The field 'children_job_statuses' was declared on serializer TopLevelJobSerializer, but has not been included in the 'fields' option.
The children_job_statuses is a property that takes a while to load. I only want to call this explicitly by calling /api/top_level_job/?fields=children_job_statuses
How can I do this? Do I need a whole new serializer?
This did the trick for me:
def get_fields(self, *args, **kwargs):
fields = super().get_fields(*args, **kwargs)
request = self.context.get('request')
if request is None or not 'fields' in request.query_params or 'children_job_statuses' not in \
request.query_params['fields']:
fields.pop('children_job_statuses', None)
return fields
I want to do the following:
models.py
class MyModel(TimeStampedModel, models.Model):
name = models.CharField(max_length=100)
owner = models.ForeignKey(settings.AUTH_USER_MODEL)
serializers.py
class MyModelSerializerCreate(serializers.ModelSerializer):
class Meta:
model = MyModel
fields = (
'name',
)
And I would like to add as owner the current user in request.user.
Currently I am adding this in my view directly by uptading request.data with user and then pass the updated data to my serializer.
data = request.data
# Add owner to data
data["owner"] = request.user.pk
serializer = self.get_serializer(data=data)
serializer.is_valid(raise_exception=True)
self.perform_create(serializer)
headers = self.get_success_headers(serializer.data)
I would like to do this in my serializer directly but can't find a way to properly do it because it looks like data validation to me. Is this a good idea ? Should I keep this logic in my views or move it to my serializer ?
You can get a user from serializer context:
self.context['request'].user
It is passed from a method get_serializer_context which originally created in a GenericAPIView:
class GenericAPIView(APIView):
....
def get_serializer_context(self):
"""
Extra context provided to the serializer class.
"""
return {
'request': self.request,
'format': self.format_kwarg,
'view': self
}
Inside a serializer you need to override a create method:
class MyModelSerializerCreate(serializers.ModelSerializer):
class Meta:
model = MyModel
fields = ('name', )
def create(self, validated_data):
validated_data['owner'] = self.context['request'].user
return super(MyModelSerializerCreate, self).create(validated_data)
You could also override an update and delete methods if you need some special interactions with the User model.
Unfortunatly I dont have the reputation points to comment on #ivan-Semochkin post above, but should the last line not be:
return super(MyModelSerializerCreate, self).create(validated_data)
The solution from Ivan Semochkin did not work for me, as it never entered into the create() method of the serializer. As request.data field is immutable, you need to copy it and then extend it.
from django.http import HttpRequest
from rest_framework.request import Request
class MyModelViewSet(ModelViewSet):
def _extend_request(self, request):
data = request.POST.copy()
data['owner'] = request.user
request_extended = Request(HttpRequest())
request_extended._full_data = data
def create(self, request, *args, **kwargs):
request_extended = self._extend_request(request)
return super().create(request_extended, *args, **kwargs)
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 have a simple model form what I use through the admin interface. Some of my model fields store datas that require a bit more time to calculate (they come from other sites). So I decided to put an extra boolean field to the form to decide to crawl these datas again or not.
class MyModelForm(forms.ModelForm):
update_values = forms.BooleanField(required=False) #this field has no model field
class Meta:
model = MyModel
This extra field doesn't exist in the model because only the form needs it.
The problem is that I only want it to appear if it's an existing record in the database.
def __init__(self, *args, **kwargs):
super(MyModelForm, self).__init__(*args, **kwargs)
if self.instance.pk is None:
#remove that field somehow
I tried nearly everything. Exclude it, delete the variable but nothing wants to work. I also tried dynamically add the field if self.instance.pk is exists but that didn't work too.
Any idea how to do the trick?
Thanks for your answers.
You could subclass the form and add the extra field in the subclass:
class MyModelForm(forms.ModelForm):
class Meta:
model = MyModel
class MyUpdateModelForm(MyModelForm):
update_values = forms.BooleanField(required=False) #this field has no model field
class Meta:
model = MyModel
You can then override the get_form method of your admin, which is passed the current instance: get_form(self, request, obj=None, **kwargs)
Rather than removing the field in __init__ if instance.pk is not None, how about adding it if it is None? Remove the class-level declaration and just change the logic:
class MyModelForm(forms.ModelForm):
class Meta:
model = MyModel
def __init__(self, *args, **kwargs):
super(MyModelForm, self).__init__(*args, **kwargs)
if self.instance and self.instance.pk is not None:
self.fields['update_values'] = forms.BooleanField(required=False)
I'm using the Django Form View and I want to enter custom choices per user to my Choicefield.
How can I do this?
Can I use maybe the get_initial function?
Can I overwrite the field?
When I want to change certain things about a form such as the label text, adding required fields or filtering a list of choices etc. I follow a pattern where I use a ModelForm and add a few utility methods to it which contain my overriding code (this helps keep __init__ tidy). These methods are then called from __init__ to override the defaults.
class ProfileForm(forms.ModelForm):
class Meta:
model = Profile
fields = ('country', 'contact_phone', )
def __init__(self, *args, **kwargs):
super(ProfileForm, self).__init__(*args, **kwargs)
self.set_querysets()
self.set_labels()
self.set_required_values()
self.set_initial_values()
def set_querysets(self):
"""Filter ChoiceFields here."""
# only show active countries in the ‘country’ choices list
self.fields["country"].queryset = Country.objects.filter(active=True)
def set_labels(self):
"""Override field labels here."""
pass
def set_required_values(self):
"""Make specific fields mandatory here."""
pass
def set_initial_values(self):
"""Set initial field values here."""
pass
If the ChoiceField is the only thing you're going to be customising, this is all you need:
class ProfileForm(forms.ModelForm):
class Meta:
model = Profile
fields = ('country', 'contact_phone', )
def __init__(self, *args, **kwargs):
super(ProfileForm, self).__init__(*args, **kwargs)
# only show active countries in the ‘country’ choices list
self.fields["country"].queryset = Country.objects.filter(active=True)
You can then make your FormView use this form with like this:
class ProfileFormView(FormView):
template_name = "profile.html"
form_class = ProfileForm