我有一个UserType和一个可用的,可以是Writer或Account。
对于GraphQL,我想也许我可以像这样使用UserableUnion:
UserableUnion = GraphQL::UnionType.define do
name "Userable"
description "Account or Writer object"
possible_types [WriterType, AccountType]
end
然后像这样定义我的UserType:
UserType = GraphQL::ObjectType.define do
name "User"
description "A user object"
field :id, !types.ID
field :userable, UserableUnion
end
但我得到schema contains Interfaces or Unions, so you must define a 'resolve_type (obj, ctx) -> { ... }' function
我曾尝试在多个地方放置一个resolve_type,但我似乎无法解决这个问题?
现在有人如何实现这个?
答案 0 :(得分:5)
该错误意味着您需要在应用架构中定义resolve_type
方法。它应该接受ActiveRecord模型和上下文,并返回GraphQL类型。
AppSchema = GraphQL::Schema.define do
resolve_type ->(record, ctx) do
# figure out the GraphQL type from the record (activerecord)
end
end
您可以实现将模型链接到类型的this example。或者,您可以在模型上创建引用其类型的类方法或属性。 e.g。
class ApplicationRecord < ActiveRecord::Base
class << self
attr_accessor :graph_ql_type
end
end
class Writer < ApplicationRecord
self.graph_ql_type = WriterType
end
AppSchema = GraphQL::Schema.define do
resolve_type ->(record, ctx) { record.class.graph_ql_type }
end
答案 1 :(得分:2)
现在在 GraphQL Ruby 中有 UnionType
https://graphql-ruby.org/type_definitions/unions.html#defining-union-types
它有明确的例子如何定义您可以使用的 UnionType。
class Types::CommentSubject < Types::BaseUnion
description "Objects which may be commented on"
possible_types Types::Post, Types::Image
# Optional: if this method is defined, it will override `Schema.resolve_type`
def self.resolve_type(object, context)
if object.is_a?(BlogPost)
Types::Post
else
Types::Image
end
end
end