HttpApi doesn't write empty strings

Not sure if I need to make an issue about HttpApi here. https://github.com/grpc/grpc-dotnet/issues/167 is for feedback, however there are 47 people subscribed to the thread which I don’t want to notify. Also https://github.com/aspnet/AspLabs has issues disabled which brings me here.

What version of gRPC and what language are you using?

Grpc.AspNetCore						: 2.32.0
Microsoft.AspNetCore.Grpc.HttpApi	: 0.1.0-alpha.20580.2
Microsoft.AspNetCore.Grpc.Swagger	: 0.1.0-alpha.20580.2

What operating system (Linux, Windows,…) and version?

Runtime Environment:
 OS Name:     Windows
 OS Version:  10.0.19042
 OS Platform: Windows
 RID:         win10-x64

What runtime / compiler are you using (e.g. .NET Core SDK version dotnet --info)

.NET SDK (reflecting any global.json):
 Version:   5.0.100
 Commit:    5044b93829

Host (useful for support):
  Version: 5.0.0
  Commit:  cf258a14b7

What did you do?

I’ve created a gRPC service that returns the following message:

message GuildUser {
    uint64 id = 1;
    string username = 2;
    string discriminator = 3;
    string nickname = 4;
}

After that I’ve followed https://docs.microsoft.com/en-us/aspnet/core/grpc/httpapi to create a REST API for the service.

What did you expect to see?

Messages with all their fields.

What did you see instead?

Messages with missing fields.

When an empty string is being written, the field is omitted. On the client-side this would cause the value to be null (or undefined in JavaScript), while it should be an empty string.

Screenshot:

[JamesNK]

It looks like emitting default values is on by default in grpc-gateway V2. I didn’t know it had changed.

In that case it should be turned on in HttpApi.

[ghost]

how to turn it on to not emit the default value in json response? i am currently use go and find no way to do this