django rest framework 在不创建模型的情况下序列化字典

Question

我的数据是这样的，我想序列化它们而不为它们创建模型。

[
  {'form': 1, 'count': 1},
  {'form': 2, 'count': 3}
]

序列化为

[
  {'form': 'my form name 1', 'count': 1},
  {'form': 'my form name 2', 'count': 3}
]

我想用serializer序列化，pk得到form name form model

class EavForm(models.Model):
    name = models.CharField(max_length=300)
    order = models.IntegerField(default=1)


# serializer
class CustomSerializer(serializers.Serializer):
    form = serializers.PrimaryKeyRelatedField(queryset=EavForm.objects.all())
    count = serializers.IntegerField()

有些错误，例如 'int' object has no attribute 'pk'

在python控制

中测试

d = [{'form': 1, 'count': 1}, {'form': 2, 'count': 1}]
s = CustomSerializer(d, many=True)
print(s.data)

# error
Traceback (most recent call last):
  File "backend/src/db_tools/del1.py", line 25, in <module>
    print(s.data)
  File "backend/lib/python3.7/site-packages/rest_framework/serializers.py", line 768, in data
    ret = super(ListSerializer, self).data
  File "backend/lib/python3.7/site-packages/rest_framework/serializers.py", line 262, in data
    self._data = self.to_representation(self.instance)
  File "backend/lib/python3.7/site-packages/rest_framework/serializers.py", line 686, in to_representation
    self.child.to_representation(item) for item in iterable
  File "backend/lib/python3.7/site-packages/rest_framework/serializers.py", line 686, in <listcomp>
    self.child.to_representation(item) for item in iterable
  File "backend/lib/python3.7/site-packages/rest_framework/serializers.py", line 530, in to_representation
    ret[field.field_name] = field.to_representation(attribute)
  File "backend/lib/python3.7/site-packages/rest_framework/relations.py", line 272, in to_representation
    return value.pk
AttributeError: 'int' object has no attribute 'pk'

Answer 1

你想要的，可以通过做以下改变来实现。

class EavForm(models.Model):
    name = models.CharField(max_length=300)
    order = models.IntegerField(default=1)


# serializer
class EvaFormPKRelatedField(PrimaryKeyRelatedField):
    def get_queryset(self):
        return EavForm.objects.all()

    def to_representation(self, value):
        return value.name


class CustomSerializer(serializers.Serializer):
    form = EvaFormPKRelatedField()
    count = serializers.IntegerField()

# Assume EvaForm exist of id 1 and 2
data = [{'form': 1, 'count': 1}, {'form': 2, 'count': 1}]
s = CustomSerializer(data=data, many=True)
print(s.data) 
""" Output
[
  {'form': 'my form name 1', 'count': 1},
  {'form': 'my form name 2', 'count': 3}
]
"""

print(s.validated_data)
""" Output
[
  {'form': <EvaForm: Evaform object (1)>, 'count': 1},
  {'form': <EvaForm: Evaform object (2)>, 'count': 3}
]
"""

请注意，.data 和 .validated_data 的输出有变化。

.data 将通过调用 .to_representation() 方法为您提供 PrimaryKeyRelatedField 的值。
.validated_data 将通过调用 .to_internal_value() 方法为您提供 PrimaryKeyRelatedField 的值。因为，经过验证的数据通过调用它的所有验证来获得每个字段的值，并且在运行验证之前内部每个字段值将通过调用它的 to_internal_value() 方法来更新，并且该值用于验证过程。

django rest framework 在不创建模型的情况下序列化字典

django rest framework serialize a dictionary without create a model

python

django

django-serializer

django-rest-framework