我目前正在开发大型代码库,我需要从任何可能的模块发送电子邮件,这些模块以python的循环依赖问题进行操作
所以我尝试使用django.apps中的apps.get_model(),但是在声明序列化程序时,模型尚未准备就绪。
所以我试图创建一个工厂函数,该函数在运行时而不是启动时构建类
from rest_framework.serializers import ModelSerializer
def make_serializer(model: str, fields: tuple, options = None, **nested_fields) -> ModelSerializer:
"""Generate a new serializer "On the fly", so the model does not have to be imported at launch time.
"""
model_object = apps.get_model(model)
input_fields = fields
if options is None:
options = {}
class Serializer(ModelSerializer):
class Meta:
model = model_object
fields = input_fields
def create(self, validated_data):
# we won't permit to create data from thoses serializers.
raise NotImplementedError
# configure nested serializers.
for nested_field in nested_fields.values():
for key, nested_serializer_class in nested_field.items():
serializer_instance = nested_serializer_class(**options.get(key, {}))
print(model, key, serializer_instance)
setattr(Serializer, key, serializer_instance)
return Serializer
我的测试模型看起来像
class Band(Model):
name = Charfield(max_length=255)
class Influencer(Model):
entity = Charfield(max_length=255)
class Submission(Model):
influencer = ForeignKey(Influencer, ...)
class Campaign(Model):
band = ForeignKey('band.Band', ...)
submissions = ManyToMany(Submission)
我的测试功能是:
def test():
serializer = make_serializer(
model='submission.Campaign',
fields=['pk', 'submissions', 'band'],
options={'submissions': {'many': True}},
nested_fields={
'submissions': make_serializer(
model='submission.Submission',
fields=('influencer',),
nested_fields={
'influencer': make_serializer('influencer.Influencer', ('entity',))
},
),
'band': make_serializer('band.Band', ('name',))
}
)
return serializer
我没有得到与test()(Campaign.objects.last()).data
一致的字段,而是得到了“ pks”,并且序列化程序看起来像:
Serializer():
pk = IntegerField(label='ID', read_only=True)
submissions = PrimaryKeyRelatedField(many=True, queryset=Submission.objects.all())
band = PrimaryKeyRelatedField(allow_null=True, queryset=Band.objects.all(), required=False)
i除外,输出如下:
{
"pk": 1,
"band": {
"name": "BobMarley",
},
"submissions": [
{
"influencer": {"entity": "The influencer's name"}
}
]
}
但是我有一个ReturnDict
包含:
{
"pk": 1,
"band": 523,
"submissions": [6, 7, 8]
}
感谢您的时间
答案 0 :(得分:-1)
在进行了很多头缓存之后,我发现声明后无法在类上进行attattr,所以我使用了基于字典的技巧
def make_serializer(model: str, fields: tuple, options = None, **nested_fields) -> ModelSerializer:
"""Generate a new serializer "On the fly", so the model does not have to be imported at launch time.
"""
name = f'Serializer_{model}'
model_object = apps.get_model(model)
input_fields = fields
if options is None:
options = {}
def create(self, validated_data):
# we won't permit to create data from thoses serializers.
raise NotImplementedError
class Meta:
model = model_object
fields = input_fields
attrs = {"Meta": Meta}
# configure nested serializers.
for key, nested_serializer_class in nested_fields.items():
attrs[key] = nested_serializer_class(**options.get(key, {}))
attrs['create'] = create
return type(ModelDictSerializer)(name, (ModelDictSerializer,), attrs)
语法类似于:
campaign_serializer = make_serializer(
model='submission.Campaign',
fields=['pk', 'submissions', 'band'],
options={'submissions': {'many': True}},
submissions=make_serializer(
model='submission.Submission',
fields=('influencer',),
influencer=make_serializer('influencer.Influencer', ('entity',))
),
band=make_serializer('band.Band', ('name',))
)
它就像一种魅力:
Serializer_submission.Campaign(<Campaign: Campaign object (9665)>):
pk = IntegerField(label='ID', read_only=True)
submissions = Serializer_submission.Submission(many=True):
influencer = Serializer_influencer.Influencer():
entity = CharField(allow_blank=True, max_length=255, required=False)
band = Serializer_band.Band():
name = CharField(max_length=255)
我希望这会对其他人有所帮助