django tastypie得到相关列总量

Question

鉴于以下来自tastypie的JSON结果，我想在check.payments_total创建一个新值，该值等于付款总额（在本例中为44.00）。有关如何做到这一点的任何线索？我完全难过了。付款是检查表的加入外键。

{
"objects": [
    {
        "check": {
            "id": "58a81b36-1ea6-403b-9902-a50cbd13cf2e",
            "number": 2,
            "payments": [
                {
                    "amount": "5.00",
                },
                {
                    "amount": "39.00",
                }
            ]
        }
    }
]
}

Answer 1

如果对于回复，您可以在资源中覆盖以下方法（代码段来自tastypie.resources.Resource）：

def alter_list_data_to_serialize(self, request, data):
    """
    A hook to alter list data just before it gets serialized & sent to the user.

    Useful for restructuring/renaming aspects of the what's going to be
    sent.

    Should accommodate for a list of objects, generally also including
    meta data.
    """
    return data

只包括类似的内容（未经过测试，认为是伪代码）：

 total_amount = 0.0
 for object in data[ 'objects' ]:
     total_amount += object[ 'amount' ]

 return { 'objects' : data[ 'objects' ], 'total_amount' : total_amount }

你应该完成。