Protobuf-net: Serializing a 3rd party class with a Stream data member

Question

How do you serialize a Stream (or more correctly Stream derived) data member of a class?

Assuming we have a 3rd Party class that we can\'t attribute:

pub         


        

Answer 1

Stream is a very complex beast, and there is no inbuilt serialization mechanism for that. Your code configures it as though it were a type with no interesting members, which is why it is coming back as empty.

For this scenario, I'd probably create a surrogate, and set it up with just:

RuntimeTypeModel.Default.Add(typeof(Fubar), false)
       .SetSurrogate(typeof(FubarSurrogate));

where:

[ProtoContract]
public class FubarSurrogate
{
    [ProtoMember(1)]
    public string Label { get; set; }
    [ProtoMember(2)]
    public int DataType { get; set; }
    [ProtoMember(3)]
    public byte[] Data { get; set; }

    public static explicit operator Fubar(FubarSurrogate value)
    {
        if(value == null) return null;
        return new Fubar {
            Label = value.Label,
            DataType = value.DataType,
            Data = value.Data == null ? null : new MemoryStream(value.Data)
        };
    }
    public static explicit operator FubarSurrogate(Fubar value)
    {
        if (value == null) return null;
        return new FubarSurrogate
        {
            Label = value.Label,
            DataType = value.DataType,
            Data = value.Data == null ?
                 null : ((MemoryStream)value.Data).ToArray()
        };
    }
}