GraphQL scalar DateType implemented with sangria

DateType.scala

case object DateCoercionViolation extends ValueCoercionViolation("Date value expected")

def parseDate(s: String) = Try(new DateTime(s, DateTimeZone.UTC)) match {
  case Success(date) => Right(date)
  case Failure(_) => Left(DateCoercionViolation)
}

val DateTimeType = ScalarType[DateTime]("DateTime",
  coerceOutput = date => ast.StringValue(ISODateTimeFormat.dateTime().print(date)),
  coerceUserInput = {
    case s: String => parseDate(s)
    case _ => Left(DateCoercionViolation)
  },
  coerceInput = {
    case ast.StringValue(s, _) => parseDate(s)
    case _ => Left(DateCoercionViolation)
  })

That looks just the ticket. thanks!