Sangria:如何处理自定义类型

Question

试着和Sangria和Slick合作。对他们来说都是新手。

我有一堆表，它们共享一个公共字段列表。斯利克对此的描述如下：

case class CommonFields(created_by: Int = 0, is_deleted: Boolean = false)

trait CommonModel {
  def commonFields: CommonFields
  def created_by = commonFields.created_by
  def is_deleted = commonFields.is_deleted
}

case class User(id: Int,
                name: String,
                commonFields: CommonFields = CommonFields()) extends CommonModel

光滑的桌子：

  abstract class CommonTable [Model <: CommonModel] (tag: Tag, tableName: String) extends Table[Model](tag, tableName) {
    def created_by = column[Int]("created_by")
    def is_deleted = column[Boolean]("is_deleted")
  }

  case class CommonColumns(created_by: Rep[Int], is_deleted: Rep[Boolean])

  implicit object CommonShape extends CaseClassShape(
    CommonColumns.tupled, CommonFields.tupled
  )

  class UsersTable(tag: Tag) extends CommonTable[User](tag, "USERS") {
    def id = column[Int]("ID", O.PrimaryKey, O.AutoInc)
    def name = column[String]("NAME")

    def * = (id,
      name,
      CommonColumns(created_by, is_deleted)) <> (User.tupled, User.unapply)
  }

  val Users = TableQuery[UsersTable]

问题在于Graphql

 lazy val UserType: ObjectType[Unit, User] = deriveObjectType[Unit, User]()

当我尝试使用UserType宏创建derivedObjectType时，它会抱怨

找不到适合.CommonFields的.CommonFields输出类型。如果您已经定义了它，请考虑将其隐式化，并确保它在作用域中可用。 UserType: ObjectTypeUnit，User = deriveObjectTypeUnit，User(

如何告诉Sangria/Graphql如何处理这个嵌套字段列表(来自CommonFields)？

请帮帮忙。

Answer 1

您正在为用户派生类型，但用户也有尚未导出的CommonFields。因此，它无法找到CommonFields的类型信息。派生两者并使派生对CommonFields而言是隐式的。

implicit val CommonFieldsType: ObjectType[Unit, CommonFields] = deriveObjectType[Unit, CommonFields]     
implicit val UserType: ObjectType[Unit, User] = deriveObjectType[Unit, User]