映射SqlAlchemy模型类时出现Unhashable Type错误_unable to serialize unknown type:

报错代码：

@dataclass()
class Order:
    """
    订单收益
    """
    id: str  # 订单标识 = order_id
    customer_id: int  # 消费者标识
    store_id: int  # 店铺标识
    price_currency: str  # 价钱单位
    commodity_price: Decimal  # 商品总价
    commodity_weight: Decimal  # 重量
    shipping_fee: Decimal  # 邮费
    tax_fee: Decimal  # 税费
    total_price: Decimal  # 总金额
    status: OrderIncomeStatus  # 订单收益状态
    payment: Optional[OrderPayment] = field(init=False, default_factory=lambda: None)  # 支付网关
	......

@dataclass()
class OrderPayment:
    """
    支付网关
    """
    id: str  # 支付单号
    gateway: str  # 支付网关: adapay chinapnr stripe
    channel: str  # 支付渠道 微信公众号, 微信小程序, 支付宝
    pipeline_id: str  # 支付商家通道
    paid_time: int  # 支付时间

    def __composite_values__(self):
        return self.id, self.gateway, self.channel, self.pipeline_id, self.paid_time

    def __eq__(self, other):
        return isinstance(other, OrderPayment) and \
               other.id == self.id and \
               other.gateway == self.gateway and \
               other.channel == self.channel and \
               other.pipeline_id == self.pipeline_id and \
               other.paid_time == self.paid_time

    def __ne__(self, other):
        return not self.__eq__(other)

orders_mapper = mapper(Order, orders, properties={
    "payment": composite(OrderPayment, orders.c.payment_id, orders.c.payment_gateway, orders.c.payment_channel,orders.c.payment_pipeline_id, orders.c.paid_time),
})
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46

报错：

unhashable type: 'OrderPayment'
1

错误原因：

当构建orm的时候，sqlalchemy会调用到子类的hash结果，但OrderPayment类中并没有hash的返回，所以会报这个错误

解决：

为OrderPayment加上__hash__方法：

@dataclass()
class OrderPayment:
    """
    支付网关
    """
    id: str  # 支付单号
    gateway: str  # 支付网关: adapay chinapnr stripe
    channel: str  # 支付渠道 微信公众号, 微信小程序, 支付宝
    pipeline_id: str  # 支付商家通道
    paid_time: int  # 支付时间

    def __composite_values__(self):
        return self.id, self.gateway, self.channel, self.pipeline_id, self.paid_time

    def __eq__(self, other):
        return isinstance(other, OrderPayment) and \
               other.id == self.id and \
               other.gateway == self.gateway and \
               other.channel == self.channel and \
               other.pipeline_id == self.pipeline_id and \
               other.paid_time == self.paid_time

    def __ne__(self, other):
        return not self.__eq__(other)
        
    def __hash__(self):
        return hash(f"{self.__class__.__module__}.{self.__class__.__name__}.{self.id}")
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27