Django Rest 框架 - “此字段是必填字段。”

Question

我有两个类，类 Amount 和 Transaction

class Account(models.Model):
user = models.ForeignKey(User, on_delete=models.CASCADE)
account_number = models.BigIntegerField(unique=True)
currency = models.CharField(max_length=3)
balance = models.DecimalField(max_digits=20, decimal_places=2, default=0)


class Transaction(models.Model):
sender_account_number = models.BigIntegerField()
recipient_account_number = models.BigIntegerField()
amount = models.DecimalField(max_digits=20, decimal_places=2)
date_creation = models.DateTimeField(auto_now_add=True)
account = models.ForeignKey(Account, on_delete=models.CASCADE)

我的序列化器：

class TransactionSerializer(serializers.ModelSerializer):
    class Meta:
        model = Transaction
        fields = ['sender_account_number', 'recipient_account_number', 'amount', 'date_creation', 'account']
        extra_kwargs = {
            'date_creation': {'read_only': True},

        }``

class AccountSerializer(serializers.ModelSerializer):
    class Meta:
        model = Account
        fields = ['id', 'account_number', 'currency', 'balance', 'user']
        extra_kwargs = {
            'balance': {'read_only': True},
            'user': {'read_only': True},
        }

我想向数据库添加一项交易，但这样它会根据帐号自动设置我的 account_id，因为一个用户可以拥有多个帐户*。 我尝试了perform_create方法

def perform_create(self, serializer):
    serializer.save(account=Account.objects.values('id').filter(
        account_number=self.request.data['sender_account_number']))

但失败了。我收到错误

{
"account": [
    "This field is required."
]

}

例如，我想发送这些数据

{

"sender_account_number": 346,
"recipient_account_number": 546,
"amount": 60

}

和Post方法：

def post(self, request):   
    serializer = TransactionSerializer(data=request.data)
    serializer.is_valid(raise_exception=True):
    return Response(serializer.data)
 

如何解决？

Answer 1

您必须告诉您的交易序列化器该帐户是外键。因此，它需要一个对象而不是字符串。
像这样添加 account = serializers.StringRelatedField()

class TransactionSerializer(serializers.ModelSerializer):
        account = serializers.StringRelatedField()
        class Meta:
            model = Transaction
            fields = ['sender_account_number', 'recipient_account_number', 'amount', 'date_creation', 'account']
            extra_kwargs = {
                'date_creation': {'read_only': True},
    
            }``

如果这样做，则不需要执行创建功能。序列化程序应该会自动为您添加它。您只需从您的帐户模型中检索带有您的帐号的实例。然后在检查序列化器是否有效后将其传递给serializer.save()。像这样

def post(self, request):
    account_number = request.data.get('sender_account_number')
    account = Account.objects.get(account_number=account)
    serializer = TransactionSerializer(data=request.data)
    serializer.is_valid(raise_exception=True):
        serializer.save(account = account_number)
    return Response(serializer.data)