问题描述
如何在默认可调用函数中访问 序列化器实例 或 任何相关参数 是DRF字段?
How can I access the serializer instance or any relevant arguments in the default callable function of DRF field?
我有一个如下的序列化器配置,
I have a serializer configuration as below,
def bar_value_callable_function(serializer_instance):
if serializer_instance.context['request'].method == 'GET':
return 'return value One'
return 'return value Two'
FooSerializer类(serializers.Serializer):bar = serializers.CharField( source ='foo.bar',默认= bar_value_callable_function )
class FooSerializer(serializers.Serializer): bar = serializers.CharField(source='foo.bar', default=bar_value_callable_function)
当我尝试将数据序列化为
and when I try to serialize the data as,
serializer = FooSerializer(foo_instance, context={'request': request})
print(serializer.data)
我犯错了,
TypeError: bar_value_callable_function() missing 1 required positional argument: 'serializer_instance'
推荐答案
更新
对于DRF> = 3.12,请使用此默认类别之王
Update
For DRF>=3.12, use this king of default class
class DefaultBarValue:
requires_context = True
def __call__(self, serializer_instance):
if serializer_instance.context['request'].method == 'GET':
return 'return value One'
return 'return value Two'
将 类实例 而不是 function 传递给 default
自变量
pass a class instance instead of function to the default
argument
# default callable class
class DefaultBarValue:
"""
"Method `set_context` on defaults is deprecated and will
no longer be called starting with 3.12. Instead set
`requires_context = True` on the class, and accept the
context as an additional argument.
"""
requires_context = True # for DRF>=3.12
serializer_instance = None # not required for DRF>=3.12
def set_context(self, serializer_instance): # not required for DRF>=3.12
self.serializer_instance = serializer_instance
def __call__(self, serializer_instance=None):
if serializer_instance is None: # will be None for older versions of DRF
if self.serializer_instance.context['request'].method == 'GET':
return 'return value One'
return 'return value Two'
else: # for DRF>=3.12
if serializer_instance.context['request'].method == 'GET':
return 'return value One'
return 'return value Two'
# serializer
class FooSerializer(serializers.Serializer):
bar = serializers.CharField(source='foo.bar', default=DefaultBarValue())
这篇关于正确使用“可调用的默认功能".在Django REST Framework(DRF)中的文章就介绍到这了,希望我们推荐的答案对大家有所帮助,也希望大家多多支持!