sangria.relay.GlobalId.scala Maven / Gradle / Ivy

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Sangria Relay Support

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package sangria.relay

import sangria.relay.util.Base64
import sangria.schema.{IDType, ScalarAlias}
import sangria.validation.{ValueCoercionViolation, Violation}

case class GlobalId(typeName: String, id: String) {
  def asString = GlobalId.toGlobalId(this)
}

object GlobalId {
  def toGlobalId(globalId: GlobalId): String = toGlobalId(globalId.typeName, globalId.id)

  /** Takes a type name and an ID specific to that type name, and returns a "global ID" that is
    * unique among all types.
    */
  def toGlobalId(typeName: String, id: String): String = Base64.encode(s"$typeName:$id")

  /** Takes the "global ID" created by toGlobalID, and returns the type name and ID used to create
    * it.
    */
  def fromGlobalId(globalId: String) =
    Base64.decode(globalId).flatMap { decoded =>
      val idx = decoded.indexOf(":")

      if (idx == -1 || idx == decoded.length - 1)
        None
      else
        Some(GlobalId(decoded.substring(0, idx), decoded.substring(idx + 1)))
    }

  def unapply(globalId: String) = fromGlobalId(globalId)

  case object IdViolation extends ValueCoercionViolation("Invalid ID")

  /** Creates a type alias to support using GlobalIDs across Relay applications
    */
  implicit val GlobalIdTypeAlias: ScalarAlias[GlobalId, String] = ScalarAlias[GlobalId, String](
    IDType,
    toScalar = _.asString,
    fromScalar = id =>
      GlobalId.fromGlobalId(id).fold[Either[Violation, GlobalId]](Left(IdViolation))(Right(_)))
}