CustomGenericSerDe.scala

package demo

import akka.serialization.SerializerWithStringManifest
import scalapb.{GeneratedMessage, GeneratedMessageCompanion}

import scala.reflect.runtime.{universe => ru}

/**
  * Custom Serializer/Deserializer for scalapb protobuf generated classes
  */
class ProtoSerDe extends SerializerWithStringManifest {

  /**
    * Serializer identifier
    * @return Int
    */
  override def identifier: Int = 9002

  /**
    * Get manifest (getClass.getName)
    * @param o Object
    * @return String
    */
  override def manifest(o: AnyRef): String = o.getClass.getName

  /**
    * Convert from object to binary
    * @param o Object
    * @return Array
    */
  override def toBinary(o: AnyRef): Array[Byte] = o match {

    case z: GeneratedMessage      => z.toByteArray
    case _   => throw new Exception(s" not a GeneratedMessage $o")

  }

  /**
    * Convert from binary to object
    * @param bytes Array
    * @param manifest String
    * @return Object
    */
  override def fromBinary(bytes: Array[Byte], manifest: String): AnyRef = {
    val runtimeMirror = ru.runtimeMirror(getClass.getClassLoader)
    val module = runtimeMirror.staticModule(manifest)
    val mm = runtimeMirror.reflectModule(module)
    val obj = mm.instance.asInstanceOf[GeneratedMessageCompanion[_]]
    obj.parseFrom(bytes).asInstanceOf[AnyRef]
  }

}