go get -u github.com/grpc-ecosystem/grpc-gateway/protoc-gen-grpc-gateway

$GOPATH/src/grpc-go-practice/
example/
|—— hello-http-2/
    |—— client/
        |—— main.go   // 客戶端
    |—— server/
        |—— main.go   // 服務(wù)端
|—— keys/                 // 證書目錄
    |—— server.key
    |—— server.pem
|—— proto/
    |—— google       // googleApi http-proto定義
        |—— api
            |—— annotations.proto
            |—— annotations.pb.go
            |—— http.proto
            |—— http.pb.go
    |—— hello_http.proto   // proto描述文件
    |—— hello_http.pb.go   // proto編譯后文件
    |—— hello_http_pb.gw.go // gateway編譯后文件

syntax = "proto3";  // 指定proto版本
package proto;     // 指定包名
import "google/api/annotations.proto";
// 定義Hello服務(wù)
service HelloHttp {
    // 定義SayHello方法
    rpc SayHello(HelloHttpRequest) returns (HelloHttpReply) {
        // http option
        option (google.api.http) = {
            post: "/example/echo"
            body: "*"
        };
    }
}
// HelloRequest 請求結(jié)構(gòu)
message HelloHttpRequest {
    string name = 1;
}
// HelloReply 響應(yīng)結(jié)構(gòu)
message HelloHttpReply {
    string message = 1;
}

cd $GOPATH/src/grpc-go-practice/example/hello-http-2/proto
# 編譯google.api
protoc -I . --go_out=plugins=grpc,Mgoogle/protobuf/descriptor.proto=github.com/golang/protobuf/protoc-gen-go/descriptor:. google/api/*.proto
# 編譯hello_http.proto
protoc -I . --go_out=plugins=grpc,Mgoogle/api/annotations.proto=git.vodjk.com/go-grpc/example/proto/google/api:. ./*.proto
# 編譯hello_http.proto gateway
protoc --grpc-gateway_out=logtostderr=true:. ./hello_http.proto

package main
import (
    "crypto/tls"
    "fmt"
    "io/ioutil"
    "log"
    "net"
    "net/http"
    "strings"
    "github.com/grpc-ecosystem/grpc-gateway/runtime"
    "golang.org/x/net/context"
    "google.golang.org/grpc"
    pb "git.vodjk.com/go-grpc/example/proto"
    "google.golang.org/grpc/credentials"
    "google.golang.org/grpc/grpclog"
)
// 定義helloHttpService并實現(xiàn)約定的接口
type helloHttpService struct{}
// HelloHttpService ...
var HelloHttpService = helloHttpService{}
func (h helloHttpService) SayHello(ctx context.Context, in *pb.HelloHttpRequest) (*pb.HelloHttpReply, error) {
    resp := new(pb.HelloHttpReply)
    resp.Message = "Hello " + in.Name + "."
    return resp, nil
}
// grpcHandlerFunc 檢查請求協(xié)議并返回http handler
func grpcHandlerFunc(grpcServer *grpc.Server, otherHandler http.Handler) http.Handler {
    return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
        // TODO(tamird): point to merged gRPC code rather than a PR.
        // This is a partial recreation of gRPC's internal checks https://github.com/grpc/grpc-go/pull/514/files#diff-95e9a25b738459a2d3030e1e6fa2a718R61
        if r.ProtoMajor == 2 && strings.Contains(r.Header.Get("Content-Type"), "application/grpc") {
            grpcServer.ServeHTTP(w, r)
        } else {
            otherHandler.ServeHTTP(w, r)
        }
    })
}
func main() {
    endpoint := "127.0.0.1:50052"
    // 實例化標準grpc server
    creds, err := credentials.NewServerTLSFromFile("../../keys/server.pem", "../../keys/server.key")
    if err != nil {
        grpclog.Fatalf("Failed to generate credentials %v", err)
    }
    conn, _ := net.Listen("tcp", endpoint)
    grpcServer := grpc.NewServer(grpc.Creds(creds))
    pb.RegisterHelloHttpServer(grpcServer, HelloHttpService)
    // http-grpc gateway
    ctx := context.Background()
    ctx, cancel := context.WithCancel(ctx)
    defer cancel()
    dcreds, err := credentials.NewClientTLSFromFile("../../keys/server.pem", "server name")
    if err != nil {
        grpclog.Fatalf("Failed to create TLS credentials %v", err)
    }
    dopts := []grpc.DialOption{grpc.WithTransportCredentials(dcreds)}
    gwmux := runtime.NewServeMux()
    err = pb.RegisterHelloHttpHandlerFromEndpoint(ctx, gwmux, endpoint, dopts)
    if err != nil {
        fmt.Printf("serve: %v\n", err)
        return
    }
    mux := http.NewServeMux()
    mux.Handle("/", gwmux)
    if err != nil {
        panic(err)
    }
    // 開啟HTTP服務(wù)
    cert, _ := ioutil.ReadFile("../../keys/server.pem")
    key, _ := ioutil.ReadFile("../../keys/server.key")
    var demoKeyPair *tls.Certificate
    pair, err := tls.X509KeyPair(cert, key)
    if err != nil {
        panic(err)
    }
    demoKeyPair = &pair
    srv := &http.Server{
        Addr:    endpoint,
        Handler: grpcHandlerFunc(grpcServer, mux),
        TLSConfig: &tls.Config{
            Certificates: []tls.Certificate{*demoKeyPair},
        },
    }
    fmt.Printf("grpc and https on port: %d\n", 50052)
    err = srv.Serve(tls.NewListener(conn, srv.TLSConfig))
    if err != nil {
        log.Fatal("ListenAndServe: ", err)
    }
    return
}

# hello-http-2/server
go run main.go
> grpc and https on port: 50052

# hello-http-2/client
go run main.go
> Hello gRPC.

curl -X POST -k https://localhost:50052/example/echo -d '{"name": "gRPC-HTTP is working!"}'
> {"message":"Hello gRPC-HTTP is working!."}