I would like to select one to many table relation in query set.I have two model.
class Post(models.Model):
postid = models.AutoField(primary_key=True)
class Meta:
db_table = 'post'
class Images(models.Model):
postid = models.ForeignKey(Post,on_delete=models.CASCADE)
image = models.ImageField(upload_to=upload_image_to, blank=True)
In list method of Post viewset, I would like to select format like=>
{
"postid": 1,
"images":[
image:"Image Result"
]
}
Here is Post viewset =>
def list(self, request):
queryset = self.queryset
page = self.paginate_queryset(queryset)
for post in self.queryset:
img = Images.objects.all().filter(postid=post.postid)
serializer = PostSerializer(page, many=True)
return self.get_paginated_response(serializer.data)
How to insert this img result to post?
Take a look at the RelatedField documentation. Something like:
class PostSerializer(serializers.ModelSerializer):
images = serializers.StringRelatedField(many=True)
class Meta:
model = Post
fields = ['postid', 'images']
This will give you a string representation of the Image, but you can look at other Relationship fields in the documentation to customise the JSON representation of the image.
Doing it like this will likely mean you don't need to override list() in the viewset as well.
Related
i set my post model with choice and migrate model.
after that i create postserializer for create
and i run the server and post with data in postman for test,
but i got the 'is not a valid choice' err on serializer.
here is my model,
class Post(models.Model):
CATEGORY_CHOICES = (
('mc', 'MIRACLE'),
('hw', 'HOMEWORK')
)
title = models.CharField(max_length=50)
category = models.CharField(max_length=2, choices=CATEGORY_CHOICES)
content = models.TextField()
author = models.ForeignKey(settings.AUTH_USER_MODEL, on_delete=models.CASCADE)
serializer,
class PostCreateSerializer(serializers.ModelSerializer):
class Meta:
model = Post
fields = '__all__'
view
class PostAPI(APIView):
def post(self, request):
data = {
'title' :request.data['title'],
'category':request.data['category'],
'content' :request.data['content'],
'author' :request.user.id
}
serializer = PostCreateSerializer(data=data)
if serializer.is_valid():
serializer.save()
else:
print(serializer.erros)
...
and request data (in Postman)
{
'title':'test_title',
'category':'HOMEWORK',
'content':'test_content'
}
result is
{'category': [ErrorDetail(string='"HOMEWORK" is not a valid choice.', code='invalid_choice')]}
i tried request with changing category 'HOMEWORK' to 'hw'
then it works
but i want request with large one
Your error on serialize level. Try this
readable_to_choice = {"HOMEWORK": "hw", "MIRACLE": "mc"}
data = {'title' :request.data['title'],
'category': readable_to_choice.get(request.data['category']),
'content' :request.data['content'],
'author' :request.user.id}
serializer = PostCreateSerializer(data=data)
UPD: you should make your api func like this:
serializer = PostCreateSerializer(data=request.data)
serializer.is_valid(raise_exception=True)
print(serializer.data) # do logic with that data
and try to override to_internal_value method in your serializer. for example:
def to_internal_value(self, data):
readable_to_choice = {"HOMEWORK": "hw", "MIRACLE": "mc"}
data["category"] = readable_to_choice.get(data["category"])
res = super().to_internal_value(data)
return res
I think this way is more accurate
I am making a POST api using DRF. In that api, I need only few fields(name, size, customer_name, customer_address), but don't require this fields(status, ordered_time) because these fields I want to save these fields in run time as status='open' and ordered_time=DateTimeField.now()
views.py
class PizzaOrderCustomerView(APIView):
def post(self, request):
orders = request.data.get('orders')
# Create an article from the above data
serializer = ArticleSerializer(data=orders)
if serializer.is_valid(raise_exception=True):
article_saved = serializer.save()
return Response({"success": "Article '{}' created successfully".format(article_saved.name)})
models.py
class PizzaOrder(models.Model):
name = models.CharField(max_length=120)
size = models.CharField(max_length=10, choices=SIZE_CHOICE, default='MEDIUM')
customer_name = models.CharField(max_length=120)
customer_address = models.TextField()
ordered_time = models.DateTimeField(default=timezone.now, editable=False)
status = models.CharField(max_length=20, default='open', editable=False)
serializers.py
class OrderSerializer(serializers.ModelSerializer):
class Meta:
model = PizzaOrder
# fields = '__all__'
read_only_fields = ('status',)
But when I try to create an order, it needed status and ordered_time also. But it should save at the time of creating order automatically.
Suggest a good way to do it.
from rest_framework import viewsets, mixins
class PizzaViewsets(viewsets.ViewSet, mixins.CreateModelMixin):
model = PizzaOrder
serializer_class = OrderSerializer
queryset = model.objects.all(
serializer, it is always good practise to mention all fields instead of
all
class OrderSerializer(serializers.ModelSerializer):
class Meta:
model = PizzaOrder
fields = ('status','ordered_time','name', 'size', 'customer_name', 'customer_address',)
read_only_fields = ('status','ordered_time',)
I am using django rest_framework to provide jsGrid json data.
As the rest_framwork example, I create a object fit the jsGrid format
class jsGridResp(object):
def __init__(self, data, itemsCount):
self.data = data
self.itemsCount = itemsCount
and the class based view, create a get function
class RateListViewSet(mixins.CreateModelMixin,
mixins.UpdateModelMixin,
mixins.DestroyModelMixin,
generics.GenericAPIView):
"""
API endpoint that allows user to be viewed or edited
"""
queryset = RateList.objects.all().order_by('-create_date')
serializer_class = RateListSerializer
def get_object(self):
queryset = self.filter_queryset(self.get_queryset())
obj = queryset.get(pk=self.request.POST["id"])
self.check_object_permissions(self.request, obj)
return obj
def get(self, request, format=None):
pageIndex = request.GET.get('pageIndex')
pageSize = request.GET.get('pageSize')
sortField = request.GET.get('sortField', 'id')
sortOrder = request.GET.get('sortOrder', 'asc')
sortOrder = "" if sortOrder == "asc" else "-"
rows = RateList.objects.all().order_by("{}{}".format(sortOrder, sortField))
itemsCount = rows.count()
paginator = Paginator(rows, pageSize)
try:
rows = paginator.page(pageIndex)
except PageNotAnInteger:
rows = paginator.page(1)
except EmptyPage:
rows = paginator.page(paginator.num_pages)
result = jsGridResp(data=rows, itemsCount=itemsCount)
serializer = RateListGetSerializer(result)
json = JSONRenderer().render(serializer.data)
return Response(json)
then I create two serializer to serialize the data
class RateListSerializer(serializers.ModelSerializer):
class Meta:
model = RateList
fields = ('id', 'rate_code', 'hr01', 'hr02', 'hr03', 'hr04', 'hr05', 'hr06',
'hr07', 'hr08', 'hr09', 'hr10', 'hr11', 'hr12', 'hr13', 'hr14',
'hr15', 'note', 'create_date', 'update_date')
read_only_fields = ('create_date', 'update_date')
def update(self, instance, validated_data):
result = instance.update(id=instance.id, **validated_data)
return result
def destroy(self, instace, validated_data):
return "{seccuess: true}"
class RateListGetSerializer(serializers.Serializer):
itemsCount = serializers.IntegerField()
data = RateListSerializer(many=True)
but I have many model need to do like these.
can I use just one serializer to serialize all model.
I want to create a jsGridGetSerializer can pass in a model parameter, so I don't need to create many simple serialzer to do the same thing.
Is this possible?
If I understand your problem correctly, you want a generic serializer which accepts a Model variable as a parameter in its Meta class.
One way to do this is to pass in the model name as a url keyword argument, then catching it in views.py. Then you can override the Meta model via overriding the get_serializer_class:
serializers.py
class GenericSerializer(serializers.ModelSerializer):
class Meta:
model = None
views.py
class GenericViewSet(viewsets.ModelViewSet):
def get_queryset(self):
model = self.kwargs.get('model')
return model.objects.all()
def get_serializer_class(self):
GenericSerializer.Meta.model = self.kwargs.get('model')
return GenericSerializer
How can I pass an argument to a serializers.RelatedField class from views.py. I need to pass language_id to query Language.objects model within that RelatedField.
I am not sure if I took a right approach to this issue. What I want to achieve is to present information about genres associated to a movie from database model about depending on the language. The MovieGenre model has genre ID field which I want to replace with actual Genre name.
My serialiser.py
class GenreField(serializers.RelatedField):
def to_representation(self, value, language_id=1):
genre_name = GenresVideo.objects.get(genre_id=value, language_id=language_id)
return genre_name.name
class MovieGenresSerializer(serializers.ModelSerializer):
genre_id = GenreField(read_only=True)
class Meta:
model = MoviesGenres
As you see, here I query Language.objects with default value but I would like to pass it from views (language_id).
My views.py:
class MovieGenresTestViewSet(viewsets.ModelViewSet):
lookup_field = 'movie'
queryset = MoviesGenres.objects.all()
serializer_class = MovieGenresSerializer
def list(self, request, language_pk):
queryset = MoviesGenres.objects.all()
serializer = MovieGenresSerializer(queryset, many=True)
return Response(serializer.data)
def retrieve(self, request, movie, language_pk):
queryset = MoviesGenres.objects.filter(movie=movie)
serializer = MovieGenresSerializer(queryset, many=True)
return Response(serializer.data)
And my urls.py:
router.register(r'lang', LanguagesViewSet, base_name='lang')
mov_gen = routers.NestedSimpleRouter(router, r'lang', lookup='language')
mov_gen.register(r'mg', MovieGenresTestViewSet, base_name='mg')
url(r'^api/', include(genre_spec.urls))
My models.py
class Languages(models.Model):
name = models.CharField(unique=True, max_length=255)
short_name = models.CharField(unique=True, max_length=4, blank=True, null=True)
active = models.BooleanField(default="")
class Meta:
managed = False
db_table = 'languages'
ordering = ('id',)
class GenresVideo(models.Model):
genre_id = models.IntegerField()
language = models.ForeignKey('Languages')
name = models.CharField(max_length=255, blank=True, null=True)
class Meta:
managed = False
db_table = 'genres_video'
unique_together = (('genre_id', 'language'),)
ordering = ('genre_id',)
class MoviesGenres(models.Model):
movie = models.ForeignKey(Movies)
genre_id = models.IntegerField()
class Meta:
managed = False
db_table = 'movies_genres'
unique_together = (('movie', 'genre_id'),)
Through the urls routes, I can get a correct response from API including the language_id. I just need to pass it to the view somehow.
Thanks a lot for help!
I'll try to answer to your first question, with the easiest implementation possible: SerializerMethodField. Because we will get the language id via the context passed to the serializer, we should either generate the context for the serializer, or let the framework do that for us.
Now to the problem at hand: you aren't filtering the queryset (MoviesGenres) by language per se. Thus, we can avoid overwriting the list and retrieve methods. Nevertheless, the router mechanism will inject in kwargs for the view method the language_pk parameter - that's the parameter that we will retrieve from within the serializer context:
class MovieGenresSerializer(serializers.ModelSerializer):
genre = searializers.SerializerMethodField()
class Meta:
model = MoviesGenres
def get_genre(self, instance):
# get the language id from the view kwargs
language_id = self.context['view'].kwargs['language_pk']
# get the genre
try:
genre_name = GenresVideo.objects.get(genre_id=instance.genre_id, language_id=language_id).name
except GenresVideo.DoesNotExist:
genre_name = None
# return the formatted output
return genre_name
class MovieGenresTestViewSet(viewsets.ModelViewSet):
lookup_field = 'movie'
queryset = MoviesGenres.objects.all()
serializer_class = MovieGenresSerializer
I think this is simple and probably a duplicate, but I cannot figure it out by looking at the documentation.
I have Django models as follows:
class Image(models.Model):
manor = models.ForeignKey(Manor, related_name='image_for_manor')
filename = models.CharField(max_length=30, null=True, blank=True)
class Manor(models.Model):
id = models.IntegerField(primary_key=True)
I want the user to be able to query the Manor and see the related Image. I'd like this JSON to be returned:
{
id: 572,
image: 'my/filepath.png'
}
This is my view:
#api_view(['GET'])
def manor(request, id):
mymanor = Manor.objects.get(id=id)
serializer = ManorSerializer(mymanor)
return JSONResponse(serializer.data)
And these are my serializers:
class ImageFilePathSerializer(serializers.ModelSerializer):
class Meta:
model = Image
fields = ('filename',)
class ManorSerializer(serializers.ModelSerializer):
image = ImageFilePathSerializer(source="image_for_manor")
class Meta:
model = Manor
fields = ('id', 'image')
But this doesn't work: I get an empty dictionary for image. (Even if it weren't empty, I realise it wouldn't be right, because I don't want the image property to be a dictionary: I want it to be a string.)
How can I change this to be correct? I cannot work it out.
As Kevin suggested , why dont you use ImageField which will give you url where your image is uploaded. although if you dont want to do that , here are some changes you have to do to get the result format you wanted.(Following solution assumes that only one image will be for one minor)
views.py ( why dont you ImageFilePathSerializer instead of another one as it also contains all the data you wanted)
#api_view(['GET'])
def manor(request, id):
mymanor = Image.objects.get(manor__id=id)
serializer = ImageFilePathSerializer(mymanor)
return Response(serializer.data)
serializers.py (add Id with filename in ImageFilePathSerializer)
class ImageFilePathSerializer(serializers.ModelSerializer):
class Meta:
model = Image
fields = ('id', 'filename',)
class ManorSerializer(serializers.ModelSerializer):
filename = serializers.ImageField(source="image_for_manor")
class Meta:
model = Manor
fields = ('id', 'filename')