Django rest api to list values ManytoMany field - django

Question

Im have two models, Manager and Template, one Template has n Managers,
I want with the template id to get all the managers of the same
I tried to make an api that takes the url template id, and filters the relationship table but it returns me empty
This my models
class Template(TimestampedModel, permissions.TemplatesPermission):
title = models.CharField(
max_length=1000,
db_column='titulo',
verbose_name='título',
db_index=True,
)
description = models.TextField(
db_column='descricao',
verbose_name='descrição',
)
active = models.BooleanField(
default=True,
)
managers = models.ManyToManyField(
Manager,
through='TemplateManager',
)
validity_date = models.DateTimeField(
db_column='data_vigencia',
verbose_name='data de vigência',
)
class Meta:
db_table = 'declaracoes_template'
verbose_name = 'Template'
verbose_name_plural = 'Templates'
def __str__(self):
return self.title
class Manager(TimestampedModel):
user = models.ForeignKey(
settings.AUTH_USER_MODEL,
models.CASCADE,
verbose_name='usuário',
)
file = models.CharField(
max_length=1000,
db_column='assinatura',
verbose_name='assinatura do gestor',
)
position = models.ForeignKey(
Position,
models.PROTECT,
db_column='cargo',
verbose_name='cargo',
)
class Meta:
db_table = 'declaracoes_gestor'
verbose_name = 'Gestores'
verbose_name_plural = 'Gestores'
def __str__(self):
return self.user
class TemplateManager(TimestampedModel):
manager = models.ForeignKey(
Manager,
on_delete=models.PROTECT,
db_column='gestor_id',
)
template = models.ForeignKey(
Template,
on_delete=models.CASCADE,
db_column='template_id',
)
This my view
class TemplateManagerView(APIView):
pagination_class = BasePagination
def get(self, request, id):
template = get_object_or_404(models.Template.objects.all(), id=id)
managers = (models.TemplateManager.objects
.filter(template=template)
.all())
serializer = serializers.ManagerSerializer(managers, many=True)
return Response(serializer.data)
and my serializers
class ManagerSerializer(serializers.ModelSerializer):
position = PositionSerializer()
user = serializers.CharField(source='user.first_name')
class Meta:
model = models.Manager
fields = ['id', 'user', 'file', 'position']
class ManagerTemplateSerializer(serializers.ModelSerializer):
manager = ManagerSerializer(many=True)
template = TemplateSerializer(many=True)
class Meta:
fields = ['manager', 'template']
model = models.Template
my url something like /id/managers

Answer 1

First, you don't need to pass a query to get_object_or_404. This will work just fine:
get_object_or_404(models.Template, id=id)
Also, you are passing the wrong queryset:
managers = (models.TemplateManager.objects
.filter(template=template)
.all())
This can be changed to this:
models.TemplateManager.objects
.filter(template=template)
Which is a queryset from TemplateManager model while you're using the serializer for
ManagerSerializer serializer for Manager model.
Now, to fix this:
1 - change model in ManagerTemplateSerializer to TemplateManager instead of Template.
2 - change serializer = serializers.ManagerSerializer(managers, many=True) to serializer = serializers.ManagerTemplateSerializer(managers, many=True)