class MerchantStampCardViewSet(viewsets.ModelViewSet):
'''
A view set for listing/retrieving/updating/deleting stamp cards for the current
merchant
'''
permission_classes = (IsMerchantAndAuthenticated, )
def get_queryset(self):
if len(MerchantProfile.objects.filter(user=self.request.user)) > 0:
merchant_profile = MerchantProfile.objects.get(user=self.request.user)
if merchant_profile.merchant:
return StampCard.objects.filter(merchant=merchant_profile.merchant)
return None
def get_serializer_class(self):
if self.request.method == 'GET':
return StampCardSerializerWithRewards
else:
return StampCardSerializer
I'm trying to make this code return the fields changed in the response body. The model class has a couple fields like name, city, province, zip code and address and through the front-end the user can only change one at a time, but I want the body of the 200 response to contain the field name changed and the new value just to confirm that a change was successful and nothing went wrong.
So for example if the user changes the name to Billy. The response should be 200 and the body should say {name : 'Billy'}
How do I do this?
You can try like this:
class YourViewSet(...):
def update(self, request, *args, **kwargs):
instance = self.get_object()
current_data = self.get_serializer(instance).data # collect current data
# next few lines of the code is from default implementation
serializer = self.get_serializer(instance, data=request.data, partial=partial)
serializer.is_valid(raise_exception=True)
self.perform_update(serializer)
if getattr(instance, '_prefetched_objects_cache', None):
instance._prefetched_objects_cache = {}
updated_data = serializer.data # now we get the updated data
response_dict = dict()
for key, value in current_data:
# find the differences
if updated_data.get(key) != value:
response_dict[key] = updated_data.get(key)
return Response(response_dict) # send the difference through response
Here I have put a override on update method. Then I have collected the dictionary data from current object and updated object. Then compared them and sent differences in a dictionary as response. FYI its an untested code.
Related
I have the following serializer setup to take in a postcode and return a list of service objects:
class ServiceSearchSerializer(Serializer):
area = CharField(max_length=16)
services = DictField(child=JSONField(), read_only=True)
def validate_area(self, value):
if re.match('^[A-Z]{1,2}[0-9][A-Z0-9]? ?([0-9][A-Z]{2})?$', value) is None:
raise ValidationError("This is not a valid postcode.")
And I tried to use this to create an API endpoint which out take in the area.
class ServiceSearchAPI(GenericAPIView):
serializer_class = ServiceSearchSerializer
def post(self, request, *args, **kwargs):
serializer = self.get_serializer(data=request.data)
if serializer.is_valid(raise_exception=True):
area = serializer.data['area']
return Response(area)
However, when trying to get the area from the serializer, it returns None. But the value for request.data['area'] is correct. Does anyone know why this is happening?
I just checked the docs and they specify returning the value. Try returning it like this:
def validate_area(self, value):
if re.match('^[A-Z]{1,2}[0-9][A-Z0-9]? ?([0-9][A-Z]{2})?$', value) is None:
raise ValidationError("This is not a valid postcode.")
return value
When I'm trying to use custom filter it's working all the time in local development, but when we deploy to Production (Docker Swarm) We found an issue that sometime the API response is return empty results randomly, but the count is correct. Below is the example results from the API
API Response
{
'count': 1,
'next': 'http://localhost:8000/api/somethings/?email=test%40example.com&limit=0&offset=0',
'previous': None,
'results': []
}
Right now we need to restart a uwsgi service (By restarting docker swarm for this service) and the problem is fixed for a moment and randomly happen again.
Here is our DRF view
class SomeView(ListCreateAPIView):
queryset = SomeModel.objects.all()
serializer_class = SomeModelSerializer
filter_backends = (OrderingFilter, DjangoFilterBackend)
filter_class = CustomFilter
ordering = ('id',)
def list(self, request, *args, **kwargs):
if request.GET.get('all', None):
# Do something
serializer = self.get_serializer(queryset, many=True)
return Response(serializer.data)
else:
return super(SomeView, self).list(self, request, *args, **kwargs)
Here is our CustomFilter
from django_filters.rest_framework.filters import CharFilter
import rest_framework_filters as filters
class CustomFilter(filters.FilterSet):
json_field_separator = '___'
json_field_is = CharFilter(name='json_field', method='filter_json_field')
json_field_is_not = CharFilter(name='json_field', method='exclude_json_field')
def split_lookup_field(self, value):
return dict(field.split(':') for field in value.split(self.json_field_separator))
def filter_json_field(self, queryset, name, value):
try:
lookup_field = self.split_lookup_field(value)
return queryset.filter(**lookup_field)
except (ValueError, FieldError):
return queryset.none()
def exclude_json_field(self, queryset, name, value):
try:
lookup_field = self.split_lookup_field(value)
except (ValueError, FieldError):
return queryset.none()
for query_arg, query_value in lookup_field.items():
queryset = queryset.exclude(**{query_arg: query_value})
return queryset
class Meta:
model = SomeModel
exclude = ['image', 'json_field']
Here is a version of Package we use for this project
Django==1.10.8
djangorestframework==3.6.4
django-filter==1.0.4
djangorestframework-filters==0.10.2
In GenericAPIView you can find a method which is called: get_queryset(), which looks like this:
def get_queryset(self):
"""
Get the list of items for this view.
This must be an iterable, and may be a queryset.
Defaults to using `self.queryset`.
This method should always be used rather than accessing `self.queryset`
directly, as `self.queryset` gets evaluated only once, and those results
are cached for all subsequent requests.
You may want to override this if you need to provide different
querysets depending on the incoming request.
(Eg. return a list of items that is specific to the user)
"""
assert self.queryset is not None, (
"'%s' should either include a `queryset` attribute, "
"or override the `get_queryset()` method."
% self.__class__.__name__
)
queryset = self.queryset
if isinstance(queryset, QuerySet):
# Ensure queryset is re-evaluated on each request.
queryset = queryset.all()
return queryset
It is a quick call, but I think your queryset is not re-evaluated on each request.
Take a look at this comment: # Ensure queryset is re-evaluated on each request.
hi im trying to save a form data into db.
i provided print of requset.data for you as you see requirement have two items.
i want to save each item in database i used for loop to save each item of list but the loop will save each character of item like h-e-l,... in table row...
where is my mistake ... thanks
also print of request.data.get('requirement') will retun second item
this is print of request.data in sever:
<QueryDict: {'requirement': ['hello', 'bye'], 'audience': ['adasd'], 'achievement': ['asdasd'], 'section': ['410101010'], 'title': ['asdasd'], 'mini_description': ['asdad'], 'full_description': ['asdasd'], 'video_length': ['10101'], 'video_level': ['P'], 'price': [''], 'free': ['true'], 'image': [<InMemoryUploadedFile: p.gif (image/gif)>]}>
view:
class StoreCreateAPIView(generics.CreateAPIView):
parser_classes = (MultiPartParser, FormParser)
permission_classes = [IsAuthenticated]
def perform_create(self, serializer):
serializer.save(author=self.request.user)
def post(self, request, *args, **kwargs):
if request.method == 'POST':
print(request.data)
file_serial = ProductSerializer(data=request.data, context={"request": request})
if file_serial.is_valid():
file_serial.save(author_id=request.user.id)
requirement = request.data['requirement']
audience = request.data.get('audience')
achievement = request.data.get('achievement')
sections = request.data.get('section')
print(request.data['requirement'])
pid = file_serial.data.get('product_id')
for item in requirement :
req = ProductRequiredItems(
item = item,
product_id = pid
)
req.save()
First of all, overriding CreateAPIView's post method in your code makes your custom perform_create method useless, unless you explicitly call it from within your customized post method. Otherwise it will never be called.
also print of request.data.get('requirement') will retun second item
It does return the last item as per Django docs for QueryDict.__getitem__(key).
i want to save each item in database i used for loop to save each item of list but the loop will save each character of item like h-e-l,...
This is because of the above functionality of QueryDict. When you do:
requirement = request.data['requirement']
# requirement = request.__getitem__('requirement')
it will call QueryDict.__getitem__(key) method and thus return only the last item (which is string in you example).
Answer:
You can simply override CreateAPIView's create method, and let your serializer handle all the rest.
# views.py
from django.shortcuts import render
from rest_framework import generics, status
from rest_framework.response import Response
from .models import MyObj
from .serializers import MyObjSerializer
class MyObjView(generics.CreateAPIView):
serializer_class = MyObjSerializer
queryset = MyObj.objects.all()
def create(self, request, *args, **kwargs):
# The QueryDicts at request.POST and request.GET will be immutable
# when accessed in a normal request/response cycle.
# To get a mutable version you need to use QueryDict.copy().
req_data = request.data.copy()
requirements = req_data.pop('requirement')
serializers_data = []
for requirement in requirements:
req_data ['requirement'] = requirement
serializer = self.get_serializer(data=req_data)
serializer.is_valid(raise_exception=True)
self.perform_create(serializer)
serializers_data.append(serializer.data)
return Response(serializers_data, status=status.HTTP_201_CREATED)
# serializers.py
from rest_framework import serializers
from .models import MyObj
class MyObjSerializer(serializers.ModelSerializer):
class Meta:
model = MyObj
fields = '__all__'
Have a look at DRF CreateModelMixin. It defines create & perform_create methods that are used used in CreateAPIView upon executing POST request. I just altered them slightly to handle your specific case.
Hope it helps.
So, according to the docs, SerializerMethodField is a read-only field.
Well in my case, it's interfering with my write:
# old value is 2.5
data={'score': 1.7}
serializer = ScoreTraitSerializer(
score_trait, data=data, partial=True)
if serializer.is_valid():
new_score_trait = serializer.save()
Now if I inspect the new_score_trait, my score is still 2.5.
The serializer looks as such:
score = serializers.SerializerMethodField()
def get_score(self, obj):
if isinstance(obj.score, decimal.Decimal):
return float(obj.score)
else:
return obj.score
If I comment out my SerializerMethodField, I can save the new decimal value (but can't serialize it).
So ... am I using my serializer correctly? Why does my write to the serializer hitting the SerializerMethodField?
Thanks in advance
SerializerMethodField is a read-only field.Only used for to_representation, it's used for list/retrieve not create/update.
the serializer field score must conflict with model field score,try change it to:
float_score = serializers.SerializerMethodField(required=False)
def get_float_score (self, obj):
if isinstance(obj.score, decimal.Decimal):
return float(obj.score)
else:
return obj.score
See the source code you will know why:
class SerializerMethodField(Field):
"""
A read-only field that get its representation from calling a method on the
parent serializer class. The method called will be of the form
"get_{field_name}", and should take a single argument, which is the
object being serialized.
For example:
class ExampleSerializer(self):
extra_info = SerializerMethodField()
def get_extra_info(self, obj):
return ... # Calculate some data to return.
"""
def __init__(self, method_name=None, **kwargs):
self.method_name = method_name
kwargs['source'] = '*'
kwargs['read_only'] = True
super(SerializerMethodField, self).__init__(**kwargs)
I have a survey app - you create a Survey and it saves the Response. It's registered in Django Admin. I can see the Survey and submit a Response. When I click Response in Admin, I get the following error:
ValueError at /admin/django_survey/response/
Cannot query "response 5f895af5999c49929a522316a5108aa0": Must be "User" instance.
So I checked the SQL database and for django_survey_response I can see that there is a response, but the column user_id is NULL.
I suspected that there's an issue with my Views and/or Forms and I'm not saving the logged in User's details, so I've tried to address that.
However, now I get
NameError at /survey/1/
global name 'user' is not defined
How do I resolve this? I want the form to save Response with the logged in user's ID.
The Traceback:
django_survey\views.py
def SurveyDetail(request, id):
survey = Survey.objects.get(id=id)
category_items = Category.objects.filter(survey=survey)
categories = [c.name for c in category_items]
print 'categories for this survey:'
print categories
if request.method == 'POST':
form = ResponseForm(request.POST, survey=survey) <.........................
if form.is_valid():
response = form.save()
return HttpResponseRedirect("/confirm/%s" % response.interview_uuid)
else:
form = ResponseForm(survey=survey)
print form
django_survey\forms.py
def __init__(self, *args, **kwargs):
# expects a survey object to be passed in initially
survey = kwargs.pop('survey')
self.survey = survey
self.user = user <.........................
super(ResponseForm, self).__init__(*args, **kwargs)
self.uuid = random_uuid = uuid.uuid4().hex
# add a field for each survey question, corresponding to the question
# type as appropriate.
data = kwargs.get('data')
It might be worth noting that previously, instead of user, the model's field was called interviewee. I changed this and ran migrations again.
I am also using userena.
The error message in this instance is python trying to tell you that you are attempting to access a variable user that has not been defined in the scope of your method.
Let's look at the first few lines of the __init__() method:
def __init__(self, *args, **kwargs):
# expects a survey object to be passed in initially
survey = kwargs.pop('survey')
self.survey = survey
self.user = user
We can see where the survey variable is defined: survey = kwargs.pop('survey'). It is passed into the form as a keyword argument and extracted in the forms __init__. However underneath you attempt to do the same thing with user but haven't actually defined it above. The correct code would look like:
def __init__(self, *args, **kwargs):
# expects a survey object to be passed in initially
survey = kwargs.pop('survey')
user = kwargs.pop('user')
self.survey = survey
self.user = user
However, this still won't work because we aren't passing the user variable to the form via kwargs. To do that we pass it in when we initialise the form in your views.py. What isn't clear is what user object you are expecting to pass in. the request.user? or does the Survey object have a user attribute? in which case you would not need to pass user in and would just use survey.user etc.
django_survey\views.py
def SurveyDetail(request, id):
survey = Survey.objects.get(id=id)
category_items = Category.objects.filter(survey=survey)
categories = [c.name for c in category_items]
print 'categories for this survey:'
print categories
if request.method == 'POST':
form = ResponseForm(request.POST, survey=survey, user=request.user)
if form.is_valid():
response = form.save()
return HttpResponseRedirect("/confirm/%s" % response.interview_uuid)
else:
form = ResponseForm(survey=survey, user=request.user)
print form
In your view when you initialize your form you need to pass it the user (current user in this case)? similar to this form = ResponseForm(request.POST, survey=survey, user=request.user). Then in the __init__ of your form pop the user object user = kwargs.pop('user'). I believe that will resolve your issue.