Java8 Date and Time API の java.time.Instant に対応させる play.api.libs.json.{Reads, Writes, Format}

gistfile1.scala

package helpers.play.api.libs.json

import play.api.data.validation.ValidationError
import play.api.libs.json._

/**
 * @see play.api.libs.json.Reads
 */
object InstantReads {

  def instantReads(formatter: java.time.format.DateTimeFormatter = java.time.format.DateTimeFormatter.ISO_INSTANT, corrector: String => String = identity): Reads[java.time.Instant] = new Reads[java.time.Instant] {

    def reads(json: JsValue): JsResult[java.time.Instant] = json match {
      case JsNumber(d) => JsSuccess(java.time.Instant.ofEpochMilli(d.toLong))
      case JsString(s) => parseDate(corrector(s)) match {
        case Some(d) => JsSuccess(d)
        case None => JsError(Seq(JsPath() -> Seq(ValidationError("error.expected.date.isoformat", formatter))))
      }
      case _ => JsError(Seq(JsPath() -> Seq(ValidationError("error.expected.date"))))
    }

    private def parseDate(input: String): Option[java.time.Instant] = {
      try {
        Some(java.time.Instant.from(formatter.parse(input)))
      } catch {
        case _: java.time.format.DateTimeParseException => None
      }
    }
  }

  implicit val IsoInstantReads = instantReads(java.time.format.DateTimeFormatter.ISO_INSTANT)

}

package helpers.play.api.libs.json

import play.api.libs.json._

/**
 * @see play.api.libs.json.Writes
 */
object InstantWrites {

  def instantWrites(formatter: java.time.format.DateTimeFormatter): Writes[java.time.Instant] = new Writes[java.time.Instant] {
    def writes(d: java.time.Instant): JsValue = JsString(formatter.format(d))
  }

  implicit val IsoInstantWrites = instantWrites(java.time.format.DateTimeFormatter.ISO_INSTANT)

}

package helpers.play.api.libs.json

import play.api.libs.json.Format

/**
 * @see play.api.libs.json.Format
 */
object InstantFormat {

  implicit val IsoInstantFormat = Format(InstantReads.IsoInstantReads, InstantWrites.IsoInstantWrites)

}