.NET7 gRPC JSON转码+OpenAPI

gRPC JSON转码

gRPC JSON 转码允许浏览器应用调用 gRPC 服务，就像它们是使用 JSON 的 RESTful API 一样。

浏览器应用不需要生成 gRPC 客户端或了解 gRPC 的任何信息。
通过使用 HTTP 元数据注释 .proto 文件，可从 gRPC 服务自动创建 RESTful API。
使应用可以同时支持 gRPC 和 JSON Web API，而无需重复为两者生成单独的服务。.

OpenAPI与gRPC Server

OpenAPI（以前称为 Swagger）是一个与语言无关的规范，用于描述 API。gRPC JSON 转码支持从转码 REST ful的 API 生成 OpenAPI。

实现Server端

通过VS新增GRPC Server，新增nuget包

<ItemGroup>  <PackageReference Include="Grpc.AspNetCore" Version="2.49.0" />  <PackageReference Include="Microsoft.AspNetCore.Grpc.JsonTranscoding" Version="7.0.0" />  <PackageReference Include="Microsoft.AspNetCore.Grpc.Swagger" Version="0.3.0" /></ItemGroup>

为api生成用于OpenAPI的注释XML文件，在Server.csproj文件中新增以下配置

<GenerateDocumentationFile>true</GenerateDocumentationFile>

Server的Program.cs中，开启JSON转码与Swagger

var builder = WebApplication.CreateBuilder(args);
// 开启JSON转码builder.Services.AddGrpc().AddJsonTranscoding();
// 配置Swaggerbuilder.Services.AddGrpcSwagger();builder.Services.AddSwaggerGen(c =>{    c.SwaggerDoc("v1", new OpenApiInfo { Title = "gRPC transcoding", Version = "v1" });    var filePath = Path.Combine(System.AppContext.BaseDirectory, "GrpcService4.xml");    c.IncludeXmlComments(filePath);    c.IncludeGrpcXmlComments(filePath, includeControllerXmlComments: true);});
var app = builder.Build();
//开启Swaggerapp.UseSwagger();app.UseSwaggerUI(c =>{    c.SwaggerEndpoint("/swagger/v1/swagger.json", "My API V1");});
app.MapGrpcService<GreeterService>();app.MapGet("/", () => "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");
app.Run();

下载GRPC JSON转码依赖的proto文件

https://github.com/dotnet/aspnetcore/blob/main/src/Grpc/JsonTranscoding/test/testassets/Sandbox/google/api/http.proto

https://github.com/dotnet/aspnetcore/blob/main/src/Grpc/JsonTranscoding/test/testassets/Sandbox/google/api/annotations.proto

并将文件放到项目的google/api/文件夹中。

修改greet.proto文件，通过option开启http选项，以一个get方法和一个post方法举例

syntax = "proto3";
import "google/api/annotations.proto";
option csharp_namespace = "GrpcService4";
package greet;
// The greeting service definition.service Greeter {  // Sends a greeting  rpc SayHello (HelloRequest) returns (HelloReply){     option (google.api.http) = {      get: "/v1/greeter/{name}"    };  };
    // Sends a greeting  rpc SayHelloPost (HelloRequestPost) returns (HelloReply){     option (google.api.http) = {      post: "/v1/greeter/post",      body:"data"    };  };}
// The request message containing the user's name.message HelloRequest {  string name = 1;}
// The request message containing the user's name.message HelloRequestPost {  HelloRequestPostData data = 1;}
message HelloRequestPostData{    string name = 1;    string gender = 2;}
// The response message containing the greetings.message HelloReply {  string message = 1;}

然后实现Server

using Grpc.Core;using GrpcService4;
namespace GrpcService4.Services{    public class GreeterService : Greeter.GreeterBase    {        private readonly ILogger<GreeterService> _logger;        public GreeterService(ILogger<GreeterService> logger){            _logger = logger;        }
        public override Task<HelloReply> SayHello(HelloRequest request, ServerCallContext context)        {            return Task.FromResult(new HelloReply            {                Message = "Hello " + request.Name            });        }
        public override Task<HelloReply> SayHelloPost(HelloRequestPost request, ServerCallContext context)        {            return Task.FromResult(new HelloReply            {                Message = "Hello " + request.Data.Name            });        }    }}

至此server的json转码开启完成，运行服务，访问swagger，即可尝试http方式请求

在支持http方式的请求的情况下，同时支持grpc请求。

实现Client端

新增控制台项目，添加以下nuget

<ItemGroup>  <PackageReference Include="Google.Protobuf" Version="3.21.9" />  <PackageReference Include="Grpc.Net.Client" Version="2.49.0" />  <PackageReference Include="Microsoft.AspNetCore.Grpc.JsonTranscoding" Version="7.0.0" />  <PackageReference Include="Grpc.Tools" Version="2.50.0">    <PrivateAssets>all</PrivateAssets>    <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>  </PackageReference></ItemGroup>

包含与server端相同的proto文件

<ItemGroup>  <Protobuf Include="Protos\greet.proto" GrpcServices="Client" /></ItemGroup>

尝试请求Server

static async Task Main(string[] args){    using var channel = GrpcChannel.ForAddress("https://localhost:7167");    var client = new Greeter.GreeterClient(channel);    var reply = await client.SayHelloAsync(new HelloRequest { Name = "GreeterClient" });    Console.WriteLine("Greeting: " + reply.Message);
    var replyPost = await client.SayHelloPostAsync(new HelloRequestPost { Data = new HelloRequestPostData { Name = "111" } });    Console.WriteLine("Greeting: " + replyPost.Message);    Console.WriteLine("Press any key to exit...");    Console.ReadKey();}

source code: https://github.com/cysnet/grpc-json-transcoding

gRPC JSON转码

OpenAPI与gRPC Server

实现Server端

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