python - Django not recognize UUID Foreign Key -

i had current model:

class apps(models.model):     """     apps são os aplicativos que terão financeiro gerido, uma empresa/usuario pode ter multiplos apps conectados     """     app_code = models.uuidfield(auto_created=true, default=uuid.uuid4, unique=true, primary_key=true)     chave_app = models.uuidfield(auto_created=true, default=uuid.uuid4, unique=true)     usuario = models.foreignkey(usuario, on_delete=models.cascade)     descricao = models.charfield(max_length=100) 

the usuario field foreignkey...

the usuario model this:

class usuario(abstractbaseuser):     """     classe que ira gerir o cliente final, cadastrado via app ou webapp     """     user_id = models.uuidfield(auto_created=true, default=uuid.uuid4, unique=true, primary_key=true)     nome = models.charfield(max_length=120)     celular = models.charfield(max_length=20, unique=false)     email = models.emailfield(max_length=100, unique=true)     ativo = models.booleanfield(default=true)     chave_api = models.uuidfield(auto_created=true, default=uuid.uuid4, unique=true)     created_at = models.datetimefield(auto_now_add=true)      objects = accountmanager()      username_field = 'chave_api'     required_fields = ['email', 'nome', 'celular']      class meta:         ordering = ('-created_at',) 

all works nice, when try list apps on django-rest-framework list. did same way on anothers models, no foreign key, , listing ok. error giving on view foreign key.

typeerror @ /apps/ str returned non-string (type uuid)

at database, fields inserted values:

[   {     "app_code": "423676e9968d41beaeeeb2da43fc56d8",     "chave_app": "86c18ae7809e4bda88830090f309a00c",     "descricao": "matrix cashback 2.0",     "usuario_id": "998339b46bde40bca053978670626a6f"   } ] 

i'm using django-rest-framework , django in personal project.

don't know now, did try lots of variants. not recognize foreign key uuid.

my serializer view this:

class appserializer(serializers.serializer):     app_code = serializers.uuidfield(read_only=true)     usuario = serializers.uuidfield(read_only=true)     descricao = serializers.charfield(required=true, max_length=100)     chave_app = serializers.uuidfield(read_only=true)     chave_api = serializers.uuidfield(required=true)      class meta:         model = apps         fields = ('app_code', 'chave_app', 'usuario', 'descricao')      def create(self, validated_data):         usuario = usuario.objects.get(chave_api=validated_data.get('chave_api'))         return apps.objects.create(             descricao=validated_data.get('descricao'),             usuario=usuario         )      def update(self, instance, validated_data):         instance.descricao = validated_data.get('descricao', instance.descricao)         instance.save()         return instance 

some welcome! thanks.

this error on browser when try "list" apps.

founded problem... when try list serializer, used uuidfield on usuario. need readonlyfield

my correct appserializer was:

class appserializer(serializers.serializer):     app_code = serializers.uuidfield(read_only=true)     usuario = serializers.readonlyfield(source='usuario.user_id')     descricao = serializers.charfield(required=true, max_length=100)     chave_app = serializers.uuidfield(read_only=true)     # chave_api = serializers.uuidfield(required=true)      class meta:         model = apps         fields = ('app_code', 'chave_app', 'usuario', 'descricao')      def create(self, validated_data):         usuario = usuario.objects.get(chave_api=validated_data.get('chave_api'))         return apps.objects.create(             descricao=validated_data.get('descricao'),             usuario=usuario         )      def update(self, instance, validated_data):         instance.descricao = validated_data.get('descricao', instance.descricao)         instance.save()         return instance