Instead of Primary Key Send Different Field in Django REST Framework
On solution is to override genre
field in your serializer, to accept a list of strings like this:
class MovieSerializer(serializers.ModelSerializer):
genre = serializer.ListField(child=serializers.CharField())
class Meta:
model = Movie
fields = [
'popularity',
'director',
'genre',
'imdb_score',
'name',
]
def validate(self, data):
genre = data.get('genre', [])
genre_obj_list = [Genre.objects.get(name=name) for name in genre.all()]
data.update({'genre': genre_obj_list})
return data
And on validate method try to fetch each object by their names and put in a new list and update data
result with new list of objects. (I know it's not the cleanest solutions, but it works fine)
you could also try to use MethodSerializer
or define a GenreSerializer
and fetch objects in that by their names and use that in the parent serializer as an input.
Override the create()
method of the serializer as below,
class MovieSerializer(serializers.ModelSerializer):
genre = serializers.ListSerializer(child=serializers.CharField())
class Meta:
model = Movie
fields = [
'popularity',
'director',
'genre',
'imdb_score',
'name',
]
def create(self, validated_data):
genre = validated_data.pop('genre',[])
movie = super().create(validated_data)
genre_qs = Genre.objects.filter(name__in=genre)
movie.genre.add(*genre_qs)
return movie
Assuming that you used StringRelatedField
in your MovieSerializer
like this:
class MovieSerializer(serializers.ModelSerializer):
genre = serializers.StringRelatedField(many=True)
class Meta:
model = Movie
fields = [
'popularity',
'director',
'genre',
'imdb_score',
'name',
]
the result would look like this when retrieving a list of movies:
[
{
"popularity": 83.0,
"director": "Victor Fleming",
"genre": [
"Adventure",
"Family",
"Fantasy",
"Musical"
],
"imdb_score": 8.3,
"name": "The Wizard of Oz"
}
]
But if you want to create a new movie, then it won't work because StringRelatedField
is read-only.
You can however create your custom related field.
This is the complete serializers.py
:
from rest_framework import serializers
from .models import Genre, Movie
class GenreRelatedField(serializers.RelatedField):
def display_value(self, instance):
return instance
def to_representation(self, value):
return str(value)
def to_internal_value(self, data):
return Genre.objects.get(name=data)
class MovieSerializer(serializers.ModelSerializer):
genre = GenreRelatedField(
queryset=Genre.objects.all(),
many=True
)
class Meta:
model = Movie
fields = (
'popularity',
'director',
'genre',
'imdb_score',
'name',
)
This is a simple example that can be highly customized in many ways.
The method display_value
defines how the object Genre is displayed, for example in the form. Here it just returns the object Genre i.e. the output of __str__
.
The method to_representation
defines how the object Genre is displayed in the output (JSON or XML). It's very similar to the previous method, but here we explicitly have to convert Genre to string. Certainly you can create a more complex output according to your requirements.
The method to_internal_value
solves your actual problem by getting an object Genre for the given value. If you have a more complex method to_representation
here you would need expanded logics to get the appropriate object.
Using this approach you can post a JSON in your desired form, specifying the genre names instead of their ids.
I hope this example helps other people too.