Question

I am using protobuf-net for performance reasons in a scenario where the assemblies that deserialize saved data are the same that serialized it.

Most of the types that I serialize are simple contracts that I marked with ProtoContract and ProtoMember attributes but occasionally I have to serialize weird objects with many subclasses (ie: Exception).

I made it work with the following workaround using classic ISerializable mechanism.

I am pretty new to protobuf-net and would like to know if this is a good idea and if there are better/standard ways to do it.

My workaround:

I defined a generic surrogate that implements classic serialization

[ProtoContract]
class BinarySerializationSurrogate<T>
{
    [ProtoMember(1)]
    byte[] objectData = null;

    public static implicit operator T(BinarySerializationSurrogate<T> surrogate)
    {
        T ret = default(T);
        if (surrogate == null)
            return ret;

        var serializer = new BinaryFormatter();
        using (var serializedStream = new MemoryStream(surrogate.objectData))
            ret = (T)serializer.Deserialize(serializedStream);

        return ret;
    }

    public static implicit operator BinarySerializationSurrogate<T>(T obj)
    {
        if (obj == null)
            return null;

        var ret = new BinarySerializationSurrogate<T>();

        var serializer = new BinaryFormatter();
        using (var serializedStream = new MemoryStream())
        {
            serializer.Serialize(serializedStream, obj);
            ret.objectData = serializedStream.ToArray();
        }

        return ret;
    }
}

In initialization code I add it as surrogate for weird base types

RuntimeTypeModel.Default
    .Add(typeof(Exception), false)
    .SetSurrogate(typeof(BinarySerializationSurrogate<Exception>));

Answer 1

That hybrid setup isn’t a scenario that protobuf-net supports directly, and it isn’t something I see as a core use-case, but your surrogate approach should work without any major problems (as long as the assemblies stay in sync).