The right way to send generic data types with protobuf3 in C#/.NET

Question

I'm developing an application using a plugins architecture and I want to send objects between client and server without knowing the type of the object being sent.

Is there a way to send generic data type ?

According to Microsoft pages, the Any field could be an answer to this problem, instead of using a string and a custom serialization/deserialization implementation to send these objects. However, I didn't find the provided c# examples understandable. I tried to solve the problem this way:

ClassTest myClassTest = new ClassTest();
Any packToSend = Any.Pack(myClassTest);

return Task.FromResult(new UnknownTEST
{
   Pathm = hai
}); ;

But it seems that I need to implement the IMessage interface in my class and I don't know how to do this.

If anyone could provide a basic example to help me understand how to do this, that would be great.

Thanks !

Ivan Ivković · Accepted Answer · 2020-07-03T11:10:00.263

You need to create protobuf messages which represent the data you're sending. You don't need to create your own classes as you did with your "ClassTest" class.

Here's an example:

point.proto:

syntax = "proto3";
option csharp_namespace = "MyProject.Namespace";

message Point {
    int32 x = 1;
    int32 y = 2;
}

generic_dto_message.proto:

syntax = "proto3";
import "google/protobuf/any.proto";
option csharp_namespace = "MyProject.Namespace";

message GenericDtoMessage {
    google.protobuf.Any data = 1;
}

C# code:

// packing
var point = new Point
{
    X = 1,
    Y = 22
};
var genericDtoMessage = new GenericDtoMessage();
genericDtoMessage.Data = Any.Pack(point);


// unpacking
var unpackedData = genericDtoMessage.Data.Unpack<Point>();
Console.WriteLine($"X: {unpackedData.X}{Environment.NewLine}Y: {unpackedData.Y}");
Console.WriteLine($"Press any key to continue...");
Console.ReadKey();

In case you are using Grpc.Tools NuGet package to generate C# code for the above written .proto files, don't forget to add this ItemGroup section to your .csproj file:

<ItemGroup>
  <Protobuf Include="point.proto" Link="point.proto" />
  <Protobuf Include="generic_dto_message.proto" Link="generic_dto_message.proto" />
</ItemGroup>

Hope it helps!

The right way to send generic data types with protobuf3 in C#/.NET

1 Answers1