Serialization and deserialization with polymorphism and protobuffet
I am trying to use protobuf-net to serialize objects. I'm not sure if what I'm trying to do with inheritance is supported, but I thought I'd check and see if it is, or if I'm just doing something wrong.
Essentially I am trying to serialize some child class and then deserialize it, but I only do it with a reference to the base class. To demonstrate:
using UnityEngine;
using System.Collections;
using ProtoBuf;
public class main : MonoBehaviour
{
// If I don't put "SkipConstructor = true" I get
// ProtoException: No parameterless constructor found for Parent
// Ideally, I wouldn't have to put "SkipConstructor = true" but I can if necessary
[ProtoContract(SkipConstructor = true)]
[ProtoInclude(1, typeof(Child))]
abstract class Parent
{
[ProtoMember(2)]
public float FloatValue
{
get;
set;
}
public virtual void Print()
{
UnityEngine.Debug.Log("Parent: " + FloatValue);
}
}
[ProtoContract]
class Child : Parent
{
public Child()
{
FloatValue = 2.5f;
IntValue = 13;
}
[ProtoMember(3)]
public int IntValue
{
get;
set;
}
public override void Print()
{
UnityEngine.Debug.Log("Child: " + FloatValue + ", " + IntValue);
}
}
void Start()
{
Child child = new Child();
child.FloatValue = 3.14f;
child.IntValue = 42;
System.IO.MemoryStream ms = new System.IO.MemoryStream();
// I don't *have* to do this, I can, if needed, just use child directly.
// But it would be cool if I could do it from an abstract reference
Parent abstractReference = child;
ProtoBuf.Serializer.Serialize(ms, abstractReference);
ProtoBuf.Serializer.Deserialize<Parent>(ms).Print();
}
}
Output:
Parent: 0
I would like it to output:
Child: 3.14 42
Is it possible? And if so, what am I doing wrong? I've read various questions on SO about inheritance and protobuf-net and they are all slightly different from this example (as far as I understood them).
source to share
You will beat yourself. The code is fine, except for one thing - you forgot to rewind the stream:
ProtoBuf.Serializer.Serialize(ms, abstractReference);
ms.Position = 0; // <========= add this
ProtoBuf.Serializer.Deserialize<Parent>(ms).Print();
Anyway, was Deserialize
reading 0 bytes (because it was at the end), thus trying to create a parent type. An empty stream works fine in terms of the protobuf spec - it just means an object with no interesting meanings.
source to share