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下面是我在我的基於SQLAlchemy的應用程序中使用的python marshmallow序列化程序。棉花糖:我如何覆蓋這個python類的構造函數?
import simplejson
from marshmallow import Schema
class MySerializer(Schema):
class Meta:
json_module = simplejson
fields = ('field1', 'field2', 'field3')
field3 = fields.Method('get_field3')
def get_field3(self, this_obj):
return "Hello"
這是我如何把這個串行:
my_argument = 1
items=MySerializer(documents=list_of_my_objects, many=True).data
現在,我想改變串行這樣的,它需要一個額外的參數(我將傳遞my_argument
)以及如果該值參數爲1,則返回"Goodbye"
代替"Hello"
。我怎樣才能做到這一點?
特別是,我不知道我怎樣才能在論證這個marshamallow架構傳遞,使得它可以從內部get_field3
。我知道我需要重寫__init__()
方法。但我不確定它應該是什麼樣子。我嘗試以下,但它沒有工作:
def __init__(self, documents, many, my_arg):
self.my_arg = my_arg
super(Schema, self).__init__(documents, many=many)
def get_field3(self, this_obj):
self.my_arg == 1:
return "Goodbye"
else:
return "Hello"
這是堆棧跟蹤我:
my_project/my_models/serializers.pyc in __init__(self, documents, many, my_arg)
---> 25 super(Schema, self).__init__(documents, many=many)
my_virtualenv/lib/python2.7/site-packages/marshmallow/schema.pyc in __init__(self, obj, extra, only, exclude, prefix, strict, many, skip_missing, context)
--> 273 self._update_fields(self.obj, many=many)
my_virtualenv/lib/python2.7/site-packages/marshmallow/schema.pyc in _update_fields(self, obj, many)
--> 636 ret = self.__filter_fields(field_names, obj, many=many)
my_virtualenv/lib/python2.7/site-packages/marshmallow/schema.pyc in __filter_fields(self, field_names, obj, many)
--> 683 attribute_type = type(obj_dict[key])
TypeError: list indices must be integers, not str