.Net Core 3.0中的gRPC

Asp.Net Core的gRPC 服务

dotnet new grpc -o GrpcGreeter

code -r GrpcGreeter

dotnet run

配置gRPC，gRPC 是通过AddGrpc方法启用的，每个 gRPC 服务通过MapGrpcService方法添加到路由管道。

public class Startup
{
    // This method gets called by the runtime. Use this method to add services to the container.
    // For more information on how to configure your application, visit https://go.microsoft.com/fwlink/?LinkID=398940
    public void ConfigureServices(IServiceCollection services)
    {
        services.AddGrpc();
    }

    // This method gets called by the runtime. Use this method to configure the HTTP request pipeline.
    public void Configure(IApplicationBuilder app, IWebHostEnvironment env)
    {
        if (env.IsDevelopment())
        {
            app.UseDeveloperExceptionPage();
        }

        app.UseRouting();

        app.UseEndpoints(endpoints =>
        {
            // Communication with gRPC endpoints must be made through a gRPC client.
            // To learn how to create a client, visit: https://go.microsoft.com/fwlink/?linkid=2086909
            endpoints.MapGrpcService<GreeterService>();
        });
    }
}

配置Kestrel，需要 HTTP/2，通过 HTTPS 进行保护。

gRPC 要求 HTTP/2。 gRPC for ASP.NET Core 验证HttpRequest为HTTP/2。在大多数现代操作系统上，Kestrel支持 HTTP/2 。 默认情况下，Kestrel 终结点配置为支持 HTTP/1.1 和 HTTP/2 连接。

用于 gRPC 的 Kestrel 终结点应使用 HTTPS 进行保护。 在开发中， https://localhost:5001当存在 ASP.NET Core 开发证书时，将自动创建 HTTPS 终结点。 不需要配置。

在生产环境中，必须显式配置 HTTPS。 在下面的appsettings示例中，提供了一个使用 HTTPS 保护的 HTTP/2 终结点：

{
  "Kestrel": {
    "Endpoints": {
      "HttpsDefaultCert": {
        "Url": "https://localhost:5001",
        "Protocols": "Http2"
      }
    },
    "Certificates": {
      "Default": {
        "Path": "<path to .pfx file>",
        "Password": "<certificate password>"
      }
    }
  }
}

或者，可以在Program.cs中配置 Kestrel 终结点：

public static IHostBuilder CreateHostBuilder(string[] args) =>
    Host.CreateDefaultBuilder(args)
        .ConfigureWebHostDefaults(webBuilder =>
        {
            webBuilder.ConfigureKestrel(options =>
            {
                // This endpoint will use HTTP/2 and HTTPS on port 5001.
                options.Listen(IPAddress.Any, 5001, listenOptions =>
                {
                    listenOptions.Protocols = HttpProtocols.Http2;
                    listenOptions.UseHttps("<path to .pfx file>", 
                        "<certificate password>");
                });
            });
            webBuilder.UseStartup<Startup>();
        });

 如果未使用 HTTPS 配置 HTTP/2 终结点，则终结点的ListenOptions.Protocols必须设置为HttpProtocols.Http2。 HttpProtocols.Http1AndHttp2无法使用，因为需要使用 HTTPS 来协商 HTTP/2。 如果没有 HTTPS，则端点的所有连接默认为 HTTP/1.1，并且 gRPC 调用失败。

使用控制台创建Grpc客户端

dotnet new console -o GrpcGreeterClient
code -r GrpcGreeterClient

gRPC 客户端项目需要以下包：

dotnet add GrpcGreeterClient.csproj package Grpc.Net.Client
dotnet add GrpcGreeterClient.csproj package Google.Protobuf
dotnet add GrpcGreeterClient.csproj package Grpc.Tools

新建Protos文件夹，将GrpcGreeter的greet.proto文件夹复制到这里，然后编辑GrpcGreeterClient.csproj，添加<Protobuf Include="Protosgreet.proto" GrpcServices="Client" />

<Project Sdk="Microsoft.NET.Sdk">

  <PropertyGroup>
    <OutputType>Exe</OutputType>
    <TargetFramework>netcoreapp3.0</TargetFramework>
  </PropertyGroup>

  <ItemGroup>
    <PackageReference Include="Google.Protobuf" Version="3.9.2" />
    <PackageReference Include="Grpc.Net.Client" Version="2.23.2" />
    <PackageReference Include="Grpc.Tools" Version="2.24.0">
      <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>
      <PrivateAssets>all</PrivateAssets>
    </PackageReference>
    <Protobuf Include="Protosgreet.proto" GrpcServices="Client" />
  </ItemGroup>

</Project>