#django #python-3.x #django-rest-framework #self-reference
#django #python-3.x #django-rest-framework #самоссылка
Вопрос:
У меня есть приведенная ниже модель комментариев, и я хочу реализовать функциональность комментариев-ответов и, в свою очередь, отправить ответ в виде JSON с использованием django rest framework. Но в ответе я получаю записи даже для ‘parent not equal to None’ в родительском узле. Я хочу, чтобы все записи, имеющие родительское значение, отображались только как дочерние.
models.py:
»’
class Comment(models.Model):
name = models.TextField('comment')
expression = models.ForeignKey('Expression', on_delete=models.CASCADE, related_name='expression')
datecreated = models.DateTimeField('date created', auto_now_add=True)
dateupdated = models.DateTimeField('date updated', auto_now=True)
parent = models.ForeignKey('self', on_delete=models.PROTECT, null=True, blank=True, related_name='replied_to')
class META:
verbose_name_plural = "comments"
ordering = ['-datecreated']
def __str__(self):
return '{}'.format(self.name)
»’
views.py:
»’
class CommentViewSet(viewsets.ModelViewSet):
comments = Comment.objects.all()
queryset = comments
serializer_class = CommentSerializer
@list_route()
def roots(self, request, *args, **kwargs):
slug = kwargs.get('slug')
expression = Expression.objects.get(author=request.user, slug=slug)
queryset = expression.expression.filter(parent=None)
serializer = self.get_serializer(queryset, many=True)
return Response(serializer.data)
»’
serializers.py:
»’
class RecursiveSerializer(serializers.Serializer):
def to_representation(self, value):
serializer = self.parent.parent.__class__(value, context=self.context)
# data = serializer.data.filter(parent!=0)
return serializer.data
class CommentSerializer(serializers.ModelSerializer):
'''
Ref: http://voorloopnul.com/blog/representing-hierarchical-data-with-django-rest-framework/
'''
expression = serializers.CharField(required=False, read_only=True)
replied_to = RecursiveSerializer(many=True, read_only=True)
class Meta:
model = Comment
read_only_fields = ('id','datecreated', 'dateupdated',)
fields = ('id','name','expression','datecreated','dateupdated','parent','replied_to')
»’
Фактический результат:
»’
[
{
"id": 5,
"name": "my new comment",
"expression": "My new expression",
"datecreated": "2019-04-19T15:38:23.174877 05:30",
"dateupdated": "2019-04-19T15:38:23.174877 05:30",
"parent": null,
"replied_to": [
{
"id": 6,
"name": "my sub comment",
"expression": "My new expression",
"datecreated": "2019-04-19T15:38:55.061534 05:30",
"dateupdated": "2019-04-23T23:56:01.846904 05:30",
"parent": 5,
"replied_to": [
{
"id": 7,
"name": "my sub sub comment",
"expression": "My new expression",
"datecreated": "2019-04-19T15:42:46.981884 05:30",
"dateupdated": "2019-04-23T23:56:38.131256 05:30",
"parent": 6,
"replied_to": []
}
]
}
]
},
{
"id": 6,
"name": "my sub comment",
"expression": "My new expression",
"datecreated": "2019-04-19T15:38:55.061534 05:30",
"dateupdated": "2019-04-23T23:56:01.846904 05:30",
"parent": 5,
"replied_to": [
{
"id": 7,
"name": "my sub sub comment",
"expression": "My new expression",
"datecreated": "2019-04-19T15:42:46.981884 05:30",
"dateupdated": "2019-04-23T23:56:38.131256 05:30",
"parent": 6,
"replied_to": []
}
]
},
{
"id": 7,
"name": "my sub sub comment",
"expression": "My new expression",
"datecreated": "2019-04-19T15:42:46.981884 05:30",
"dateupdated": "2019-04-23T23:56:38.131256 05:30",
"parent": 6,
"replied_to": []
}
]
»’
Ожидаемый вывод:
»’
[
{
"id": 1,
"name": "new comment1",
"expression": "My new expression1",
"datecreated": "2019-04-07T17:52:52.784429 05:30",
"dateupdated": "2019-04-07T17:52:52.784429 05:30",
"parent": null,
"replied_to": []
},
{
"id": 5,
"name": "my new comment",
"expression": "My new expression",
"datecreated": "2019-04-19T15:38:23.174877 05:30",
"dateupdated": "2019-04-19T15:38:23.174877 05:30",
"parent": null,
"replied_to": [
{
"id": 6,
"name": "my sub comment",
"expression": "My new expression",
"datecreated": "2019-04-19T15:38:55.061534 05:30",
"dateupdated": "2019-04-23T23:56:01.846904 05:30",
"parent": 5,
"replied_to": [
{
"id": 7,
"name": "my sub sub comment",
"expression": "My new expression",
"datecreated": "2019-04-19T15:42:46.981884 05:30",
"dateupdated": "2019-04-23T23:56:38.131256 05:30",
"parent": 6,
"replied_to": []
}
]
}
]
},
]
»’
Ответ №1:
Изменил представления, как показано ниже: «‘
class CommentViewSet(viewsets.ModelViewSet):
queryset = Comment.objects.all()
serializer_class = CommentSerializer
def list(self, request, **kwargs):
slug = kwargs.get('slug')
try:
expression = Expression.objects.get(author=request.user, slug=slug)
queryset = expression.expression.filter(parent=None)
serializer = self.get_serializer(queryset, many=True)
return Response(serializer.data)
except Expression.DoesNotExist as err:
return Response(data={'error':'Expression matching query does not exist.'}, status=status.HTTP_404_NOT_FOUND)
»’
Теперь я получаю желаемую иерархию, как показано ниже:
»’
[
{
"id": 5,
"name": "my new comment",
"expression": "My new expression",
"datecreated": "2019-04-19T15:38:23.174877 05:30",
"dateupdated": "2019-04-19T15:38:23.174877 05:30",
"parent": null,
"replied_to": [
{
"id": 6,
"name": "my sub comment",
"expression": "My new expression",
"datecreated": "2019-04-19T15:38:55.061534 05:30",
"dateupdated": "2019-04-23T23:56:01.846904 05:30",
"parent": 5,
"replied_to": [
{
"id": 7,
"name": "my sub sub comment",
"expression": "My new expression",
"datecreated": "2019-04-19T15:42:46.981884 05:30",
"dateupdated": "2019-04-23T23:56:38.131256 05:30",
"parent": 6,
"replied_to": []
}
]
}
]
},
{
"id": 8,
"name": "new test user comment",
"expression": "My new expression",
"datecreated": "2019-04-24T00:43:57.939082 05:30",
"dateupdated": "2019-04-24T00:43:57.939082 05:30",
"parent": null,
"replied_to": []
}
]
»’