這邊開始介紹， gRPC 裡面的 Server Stream 該怎麼進行，下面先來做一下前置作業

.proto 檔設定如下

syntax = "proto3";

// Server/Client 記得調整對應的 namespace
option csharp_namespace = "MyGrpcServer";

package streamDemo;

service StreamdemoService {
	rpc HelloReplyWithCount (StreamRequest) returns (stream StreamReply);
}

message StreamRequest{
	string Name = 1;
	int32 Count = 2;
}

message StreamReply{
	string Message = 1;
}

接著新增一個 StreamDemoService.cs 檔

Server

using Grpc.Core;

namespace MyGrpcServer.Services
{
    public class StreamDemoService : StreamdemoService.StreamdemoServiceBase
    {
        public override async Task HelloReplyWithCount(StreamRequest request,
            IServerStreamWriter<StreamReply> responseStream,
            ServerCallContext context)
        {
            int count = request.Count;

            for (int i = 0; i <= count; i++)
            {
                await responseStream.WriteAsync(new StreamReply() { Message = $"Hello {request.Name},Reply Count: {i}" });
            }
        }
    }
}

Program.cs 記得要 Map 上面的服務，這樣才能正確的啟動

app.MapGrpcService<StreamDemoService>();

Client

GrpcChannel channel = GrpcChannel.ForAddress("https://localhost:7204");
var client = new StreamdemoService.StreamdemoServiceClient(channel);

var res = client.HelloReplyWithCount(new StreamRequest() { Name = "Server Stream Demo", Count = 5 });

await foreach (var item in res.ResponseStream.ReadAllAsync())
{
    Console.WriteLine(item.Message);
};

這樣我們就能啟動一個基本的 ServerStream 服務了