序列化Python类中的@property方法
在序列化Django模型类时,有没有办法将@property定义传递给json序列化程序 例如:序列化Python类中的@property方法,python,django,serialization,Python,Django,Serialization,在序列化Django模型类时,有没有办法将@property定义传递给json序列化程序 例如: class FooBar(object.Model) name = models.CharField(...) @property def foo(self): return "My name is %s" %self.name 要序列化到: [{ 'name' : 'Test User', 'foo' : 'My name is T
class FooBar(object.Model)
name = models.CharField(...)
@property
def foo(self):
return "My name is %s" %self.name
要序列化到:
[{
'name' : 'Test User',
'foo' : 'My name is Test User',
},]
您可以使用一些黑魔法获得类的所有属性:
def list_class_properties(cls):
return [k for k,v in cls.__dict__.iteritems() if type(v) is property]
例如:
>>> class Foo:
@property
def bar(self):
return "bar"
>>> list_class_properties(Foo)
['bar']
然后,您可以构建字典并从中序列化它。您可以扩展Django的序列化程序,而无需/太/多的工作。这里是一个自定义序列化程序,它接受一个查询集和一个属性列表(字段或非字段),并返回JSON
from StringIO import StringIO
from django.core.serializers.json import Serializer
class MySerializer(Serializer):
def serialize(self, queryset, list_of_attributes, **options):
self.options = options
self.stream = options.get("stream", StringIO())
self.start_serialization()
for obj in queryset:
self.start_object(obj)
for field in list_of_attributes:
self.handle_field(obj, field)
self.end_object(obj)
self.end_serialization()
return self.getvalue()
def handle_field(self, obj, field):
self._current[field] = getattr(obj, field)
用法:
>>> MySerializer().serialize(MyModel.objects.all(), ["field1", "property2", ...])
>>> ExtJsonSerializer().serialize(MyModel.objects.all(), fields=['myfield', ...], props=['myprop', ...])
当然,这可能比编写自己更简单的JSON序列化程序要多,但也可能比编写自己的XML序列化程序要少(除了更改基类外,还必须重新定义“handle_field”以匹配XML大小写)。自2010年以来,情况发生了一些变化,因此@user85461的答案似乎不再适用于Django 1.8和Python 3.4。这是一个更新的答案,似乎对我有用
from django.core.serializers.base import Serializer as BaseSerializer
from django.core.serializers.python import Serializer as PythonSerializer
from django.core.serializers.json import Serializer as JsonSerializer
from django.utils import six
class ExtBaseSerializer(BaseSerializer):
""" Abstract serializer class; everything is the same as Django's base except from the marked lines """
def serialize(self, queryset, **options):
self.options = options
self.stream = options.pop('stream', six.StringIO())
self.selected_fields = options.pop('fields', None)
self.selected_props = options.pop('props', None) # added this
self.use_natural_keys = options.pop('use_natural_keys', False)
self.use_natural_foreign_keys = options.pop('use_natural_foreign_keys', False)
self.use_natural_primary_keys = options.pop('use_natural_primary_keys', False)
self.start_serialization()
self.first = True
for obj in queryset:
self.start_object(obj)
concrete_model = obj._meta.concrete_model
for field in concrete_model._meta.local_fields:
if field.serialize:
if field.rel is None:
if self.selected_fields is None or field.attname in self.selected_fields:
self.handle_field(obj, field)
else:
if self.selected_fields is None or field.attname[:-3] in self.selected_fields:
self.handle_fk_field(obj, field)
for field in concrete_model._meta.many_to_many:
if field.serialize:
if self.selected_fields is None or field.attname in self.selected_fields:
self.handle_m2m_field(obj, field)
# added this loop
if self.selected_props:
for field in self.selected_props:
self.handle_prop(obj, field)
self.end_object(obj)
if self.first:
self.first = False
self.end_serialization()
return self.getvalue()
# added this function
def handle_prop(self, obj, field):
self._current[field] = getattr(obj, field)
class ExtPythonSerializer(ExtBaseSerializer, PythonSerializer):
pass
class ExtJsonSerializer(ExtPythonSerializer, JsonSerializer):
pass
用法:
>>> MySerializer().serialize(MyModel.objects.all(), ["field1", "property2", ...])
>>> ExtJsonSerializer().serialize(MyModel.objects.all(), fields=['myfield', ...], props=['myprop', ...])
Rafay Aleem和Wtower提出的解决方案运行良好,但它复制了大量代码。这里有一个改进:
from django.core.serializers.base import Serializer as BaseSerializer
from django.core.serializers.python import Serializer as PythonSerializer
from django.core.serializers.json import Serializer as JsonSerializer
class ExtBaseSerializer(BaseSerializer):
def serialize_property(self, obj):
model = type(obj)
for field in self.selected_fields:
if hasattr(model, field) and type(getattr(model, field)) == property:
self.handle_prop(obj, field)
def handle_prop(self, obj, field):
self._current[field] = getattr(obj, field)
def end_object(self, obj):
self.serialize_property(obj)
super(ExtBaseSerializer, self).end_object(obj)
class ExtPythonSerializer(ExtBaseSerializer, PythonSerializer):
pass
class ExtJsonSerializer(ExtPythonSerializer, JsonSerializer):
pass
如何使用它:
ExtJsonSerializer().serialize(MyModel.objects.all(), fields=['field_name_1', 'property_1' ...])
ExtJsonSerializer().serialize(MyModel.objects.all(), props=['property_1', ...])
这是M.Rafay Aleem和W.Towers answer和caots的组合。 这是干,让你只指定额外的道具,而不是所有的领域和道具在caots版本
from django.core.serializers.json import Serializer as JsonSerializer
from django.core.serializers.python import Serializer as PythonSerializer
from django.core.serializers.base import Serializer as BaseSerializer
class ExtBaseSerializer(BaseSerializer):
def serialize(self, queryset, **options):
self.selected_props = options.pop('props')
return super(ExtBaseSerializer, self).serialize(queryset, **options)
def serialize_property(self, obj):
model = type(obj)
for field in self.selected_props:
if hasattr(model, field) and type(getattr(model, field)) == property:
self.handle_prop(obj, field)
def handle_prop(self, obj, field):
self._current[field] = getattr(obj, field)
def end_object(self, obj):
self.serialize_property(obj)
super(ExtBaseSerializer, self).end_object(obj)
class ExtPythonSerializer(ExtBaseSerializer, PythonSerializer):
pass
class ExtJsonSerializer(ExtPythonSerializer, JsonSerializer):
pass
如何使用它:
ExtJsonSerializer().serialize(MyModel.objects.all(), fields=['field_name_1', 'property_1' ...])
ExtJsonSerializer().serialize(MyModel.objects.all(), props=['property_1', ...])
这实际上需要创建我自己的散列,只需要序列化为一个散列。如果我走这条路,我几乎可以删掉整个系列化。我希望继续使用django模型类并简单地调用serialize('json',my_object,…),不幸的是,django的核心序列化例程似乎特别排除了
\u meta
中没有的任何内容,它基本上只查找db模型字段。因此,虽然您可以编写一个只提取属性字段的函数(这可能最好在事后使用inspect.getmembers
方法),但即使使用serializer.serialize
方法上的fields
参数,也无法工作。在这里,他们迭代传递的查询集,只在\u meta
中查找内容:获取'MySerializer'对象没有属性'first'
Django(1.5.4)上的错误我发现前面的答案更适合同时传递字段和属性,因为否则您无法在响应中限制模型中的字段。在初始查询中,似乎所有这些都不能与.values()一起使用。@Patrick我也可以用这种方法筛选字段。尝试类似的方法:ExtJsonSerializer().serialize(MyModel.objects.all(),fields=('a','b',…),props=['property_1',…])