如何使Graphene输入类变量可选？

Question

在GraphQL更新中，我希望能够传递子对象的值，但我希望每个值都是可选的。

所以我创建了一个这样的输入类：

class CityCouncilInput(graphene.InputObjectType):
  mayor = graphene.String()
  treasurer = graphene.String()

现在，我希望能够传递市长和财务主管的价值，或只传递其中一个。

如果所有值都被传入，请知道我的代码工作正常。我只想让这些字段值是可选的。我怎么做？

罗伯特

Answer 1

你可以试试

class CityCouncilInput(graphene.InputObjectType):
  mayor = graphene.String(required=False, default=None)
  treasurer = graphene.String(required=False, default=None)

Answer 2

我认为最简单的方法是为变异函数定义一个默认参数

假设您有以下模型，其中您的值可以为空（注意：我假设mayor和treasurer都将被允许为空白而不是NULL - 否则我猜您可以将None作为默认参数传递）：

class CityCouncil(models.Model):
    mayor = models.TextField(max_length=1000, blank=True)
    treasurer = models.CharField(max_length=1000, blank=True)

然后创建市议会这应该工作：

class createCityCouncil(graphene.Mutation):
    mayor = graphene.String()
    treasurer = graphene.String()

    class Arguments:
        mayor = graphene.String()
        treasurer = graphene.String()

    def mutate(self, mayor="", treasurer=""):

        council = CityCouncil(mayor=mayor, treasurer=treasurer)
        council.save()

        return createCityCouncil(
            mayor=council.mayor, 
            treasurer=council.treasurer
        )

同样，在执行更新变异时，您可以传入可选参数，并使用setattr选择性地更新对象的属性。

class updateCityCouncil(graphene.Mutation):
    mayor = graphene.String()
    treasurer = graphene.String()

    class Arguments:
        mayor = graphene.String()
        treasurer = graphene.String()

    def mutate(self, info, id, **kwargs):
        this_council=CityCouncil.objects.get(id=id)
        if not this_council:
            raise Exception('CityCouncil does not exist')

        for prop in kwargs:
            setattr(this_council, prop, kwargs[prop])

        this_council.save

        return updateCityCouncil(
            mayor=this_council.mayor, 
            treasurer=this_council.treasurer
        )