如何编写模式并查询嵌套的外键?我检查了文档,但没有找到如何执行此操作的示例。所以这是我基于github的尝试,而stackoverflow答案可以说我有以下模型:
class Address(models.Model):
name = models.CharField()
class Person(models.Model):
name = models.CharField()
address = models.ForeignKey('Address', on_delete=models.CASCADE, blank=False, null=False)
class Blog(models.Model):
person = models.ForeignKey('Person', on_delete=models.CASCADE, blank=False, null=False)
text = models.TextField()
我尝试编写这样的模式:
class AddressInput(graphene.InputObjectType):
name = graphene.String(required=True)
class PersonInput(graphene.InputObjectType):
name = graphene.String(required=True)
address =graphene.Field(AddressInput)
class CreateNewBlog(graphene.Mutation):
blog=graphene.Field(BlogType)
class Arguments:
address_data = AddressInput()
person_data = PersonInput()
text = graphene.String()
@staticmethod
def mutate(root, info, person_data=None, address_data=None, **input):
address = Address.objects.create(name=address_data.name)
person = Person.objects.create(address=address, name=person_data.name)
blog = Blog.objects.create(person =person, text=input['text'])
blog.save()
return CreateNewBlog(blog=blog)
我使用了这样的查询:
mutation {
CreateNewBlog(person: { address: {name: "aaa"},
name: "First Last" }, text: "hi hi") {
Blog {
person{
name
address{
name
}
},
text
}
}
}
我收到此错误消息:
{
"errors": [
{
"message": "'NoneType' object has no attribute 'name'",
"locations": [
{
"line": 32,
"column": 9
}
],
"path": [
"CreateNewBlog"
]
}
],
"data": {
"CreateNewBlog": null
}
}
我认为问题出在我编写schema.py文件的方式中。无法将InputField嵌套在另一个InputField中的地方。还有其他写单个突变的方法吗?
答案 0 :(得分:1)
好的,这里有几件事。首先,您应该生成schema.graphql
文件,因为这将向您显示Graphene构建的架构的实际最终形状,这将使调试更加容易。或者,您可以使用GraphiQL来测试您的查询,并让其文档和自动完成功能为您完成繁重的工作。
但是,具体来说,您的石墨烯突变定义将产生如下所示的突变:
input AddressInput {
name: String!
}
input PersonInput {
name: String!
address: AddressInput
}
type CreateNewBlogOutput {
blog: Blog
}
type Mutation {
CreateNewBlog(addressData: AddressInput, personData: PersonInput, text: String): CreateNewBlogOutput!
}
值得一提的是,这里有两种方法可以提供AddressInput,一种是在根目录下提供,另一种是在PersonInput内提供。这可能不是您打算要做的。其次,不需要任何根参数,这会导致您的错误消息相当无用,因为问题在于您调用了不正确的突变参数,但是查询验证器却允许它通过,因为您的类型非常宽松。 >
我相信,如果您要像下面那样运行突变,它实际上会起作用:
mutation {
CreateNewBlog(
personData: {
address: {
name: "aaa"
},
name: "First Last"
},
text: "hi hi"
) {
blog {
person {
name
address {
name
}
}
text
}
}
}
我在这里只作了两个更改,person
更改为personData
(为了匹配您的突变定义,Graphene自动进行从蛇形到驼峰形的对话),以及Blog
到blog
在字段选择中。
但是,让我们再进一步一点,这就是我进行突变的方式。
class AddressInput(graphene.InputObjectType):
name = graphene.String(required=True)
class PersonInput(graphene.InputObjectType):
name = graphene.String(required=True)
address = AddressInput(required=True)
class CreateNewBlogInput(graphene.InputObjectType):
person = PersonInput(required=True)
text = graphene.String(required=True)
class CreateNewBlogPayload(graphene.ObjectType):
blog = graphene.Field(BlogType, required=True)
class CreateNewBlog(graphene.Mutation):
class Arguments:
input_data = CreateNewBlogInput(required=True, name="input")
Output = CreateNewBlogPayload
@staticmethod
def mutate(root, info, input_data):
address = Address.objects.create(name=input_data.person.address.name)
person = Person.objects.create(address=address, name=input_data.person.name)
blog = Blog.objects.create(person=person, text=input_data.text)
blog.save()
return CreateNewBlogPayload(blog=blog)
在构造Graphene的突变对象时,我也会将CreateNewBlog
更改为createNewBlog
,因为GraphQL约定是使用小驼峰进行突变。
然后您将像这样运行它:
mutation {
createNewBlog(
input: {
person: {
address: {
name: "aaa"
},
name: "First Last"
}
text: "hi hi"
}
) {
blog {
person {
name
address {
name
}
}
text
}
}
}
为什么将整个输入包装在单个输入字段中?主要是因为它使使用变量时在客户端中更容易调用突变,因此您只能提供正确形状的单个输入arg,而不是多个。
// So instead of this
mutation OldCreateNewBlog($person: PersonInput, $text: String) {
createNewBlog(
personData: $person
text: $text
) {
blog {
person {
name
address {
name
}
}
text
}
}
}
// You have this
mutation NewCreateNewBlog($input: CreateNewBlogInput!) {
createNewBlog(
input: $input
) {
blog {
person {
name
address {
name
}
}
text
}
}
}
后者使随着时间的推移更改输入形状变得更加容易,而只需在客户端代码中的一个位置进行更改。