Question

I have data in a Protocol Buffers format which can be described as follows

message Sections {
    repeated Section sections = 1;
}

message Section {
    required uint32 type = 1;
    required bytes payload = 2;
}

message SectionType1 {
    required int32 fieldType1 = 1;
    // ...
}

message SectionType2 {
    required int32 fieldType2 = 1;
    // ...
}

message SectionType3 {
    required int32 fieldType3 = 1;
    // ...
}

I’m using the protobuf-net library (+ protogen + precompile).
How do I deserialize such data into DTOs similar to

public class Sections
{
    public List<Section> Sections { get; }
}

public abstract class Section
{
}

public class SectionType1 : Section
{
    public int FieldType1 { get; }
}

public class SectionType2 : Section
{
    public int FieldType2 { get; }
}

public class SectionType3 : Section
{
    public int FieldType3 { get; }
}

Is it possible to work with such data from .NET (using precompilation since I’m on a light framework)?

Answer 1

To do that, you would have to do it manually – i.e. have

[ProtoContract]
public abstract class Section
{
    [ProtoMember(1)] public int Type {get;set;}
    [ProtoMember(2)] public byte[] Payload {get;set;}
}

and handle the rest manually. protobuf-net inheritance maps top the following .proto schema:

message Section {
    optional SectionType1 Type1 = 1;
    optional SectionType2 Type2 = 2;
    optional SectionType3 Type3 = 3;
}

where we have, say:

[ProtoInclude(1, typeof(SectionType1)]
[ProtoInclude(2, typeof(SectionType2)]
[ProtoInclude(3, typeof(SectionType3)]
public abstract class Section
{
}