I have two models:
class Album(models.Model):
name = models.CharField()
class Track(models.Model):
album = models.ForeignKey(Album)
name = models.CharField()
I can't understand how to create a Track instance, with a POST endpoint /tracks, passing album id instead of album object, but keeping album object with GET requests.
You need to create Serializer for your class and do this:
def post(self, request, albumId, format=None):
try:
album = Album.objects.get(pk=albumId)
except Sensor.DoesNotExist:
raise Http404
serializer = TrackSerializer(data=request.data)
if serializer.is_valid():
serializer.validated_data["album_id"] = album.id
measurement = serializer.save()
Serializer that allows Track.album to be null:
class TrackSerializer(serializers.HyperlinkedModelSerializer):
album= PrimaryKeyRelatedField(queryset=Album.objects.all(), required=False)
class Meta:
model = Track
fields = ('id', 'name;)
And url:
url(r'^albums/(?P<albumId>[0-9]+)/$', views.AlbumView.as_view(), name='albums'),
You post a Track object to yourURL/{albumId} to add it to album with id = albumId
Related
Here i am trying to create serializer instance without data argument because all i want to create a "Like" object which requires "user" object which i can get from request and "post" object that i am getting through querying Post model with pk but since i am not passing any data argument while deserializing it will throw an error.
So how can create instance without passing data argument or do i have to change my code and add data argument?
class Like(models.Model):
post = models.ForeignKey(Post, on_delete=models.CASCADE, related_name="likes")
liked_by = models.ForeignKey(User, on_delete=models.RESTRICT, related_name = "liked_posts")
def __str__(self):
return "{0} liked by {1}".format(self.post.img, self.liked_by.username)
class LikeSerializer(serializers.ModelSerializer):
liked_by = UserSerializer(read_only=True)
class Meta:
model = Like
fields = ("id","post", "liked_by")
class AddLike(APIView):
permission_classes = [IsAuthenticated]
def post(self, request, pk):
post = Post.objects.get(pk=pk)
user = request.user
serializer = LikeSerializer()
if not serializer.is_valid():
return Response(serializer.errors, status=status.HTTP_400_BAD_REQUEST)
serializer.save(post=post, liked_by=user)
return Response(data= serializer.data, status=status.HTTP_201_CREATED)
I think you can set the post field as read_only in the LikeSerializer.
class LikeSerializer(serializers.ModelSerializer):
liked_by = UserSerializer(read_only=True)
class Meta:
model = Like
fields = ("id","post", "liked_by")
extra_kwargs = {
'post': { 'read_only': True }
}
I got a model that looks like this:
class Book(models.Model):
author = models.CharField(max_length=100)
chapters = models.IntegerField()
name = models.CharField(max_length=100)
and a "grand child" linked together through a Chapter model:
class Verse(models.Model):
chapter = models.ForeignKey(Chapter, on_delete=CASCADE)
verse = models.TextField()
verse_number = models.IntegerField()
I wish to get the count of all verses that belongs to a book, and I'm fetching them like this:
Book.objects.annotate(Count('chapters', distinct=True), total_num_verses=Count('chapter__verse', distinct=True))
However, I'm not sure how to get this into my serializer. I was thinking of using a SerializerMethodField The goal is to get the total_num_verses as a key/value pair in my json response
class BookSerializer(serializers.ModelSerializer):
total_verse_count = serializers.SerializerMethodField()
class Meta:
model = Book
fields = "__all__"
# this doesn't work..
def get_total_verse_count(self, obj):
print(obj.get_verses)
return self.annotate(Count('chapters', distinct=True), total_num_verses=Count('chapter__verse', distinct=True))
I just get 'BookSerializer' object has no attribute 'annotate'
Should I make a #property method in the Book model class itself?
views.py is just a plain APIView
class BookAPIView(APIView):
"""
List all books
"""
def get(self, request, format=None):
books = Book.objects.all()
serializer = BookSerializer(books, many=True)
return Response(serializer.data)
An effective way to do that is adding a readonly=True field in the serializer:
class BookSerializer(serializers.ModelSerializer):
total_verse_count = serializers.IntegerField(read_only=True)
class Meta:
model = Book
fields = ['author', 'chapters', 'name', 'total_verse_count']
In the view, you then pass the annotated queryset to the serializer:
class BookAPIView(APIView):
def get(self, request, format=None):
books = Book.objects.annotate(
total_verse_count=Count('chapter__verse')
)
serializer = BookSerializer(books, many=True)
return Response(serializer.data)
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 have this serializer:
class ReviewSerializer(serializers.ModelSerializer):
user = UserSerializer(read_only=True)
class Meta:
model = Review
fields = ('pk', 'title', 'user', 'movie', 'timestamp', 'review_text',)
I want to mention that user and movie are both ForeignKeys defined in models.py for Review model. Here is the model:
class Review(models.Model):
title = models.CharField(max_length=255)
user = models.ForeignKey(User, on_delete=models.CASCADE, related_name='reviews')
movie = models.ForeignKey(Movie, on_delete=models.CASCADE, related_name='reviews')
review_text = models.TextField()
timestamp = models.DateTimeField(auto_now_add=True)
def __str__(self):
return '{movie} review by {user}'.format(user=self.user, movie=self.movie)
I want to create a viewset, but if I do something like this:
class ReviewsViewSet(viewsets.ModelViewSet):
queryset = Movie.objects.all()
serializer_class = ReviewSerializer
and register it like this:
router.register(r'reviews', views.ReviewsViewSet, 'reviews')
won't work, it requires me to provide a movie field as logged here:
AttributeError at /api/reviews/
Got AttributeError when attempting to get a value for field `movie` on serializer `ReviewSerializer`.
The serializer field might be named incorrectly and not match any attribute or key on the `Movie` instance.
Original exception text was: 'Movie' object has no attribute 'movie'.
Thanks in advance.
Edited.
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