add response header (#1119)

* add response header

Co-authored-by: chenzhihui <zhihui_chen@foxmail.com>

examples/header/client/main.go

@@ -0,0 +1,55 @@
+package main
+
+import (
+	"context"
+	"log"
+	stdhttp "net/http"
+
+	"github.com/go-kratos/kratos/examples/helloworld/helloworld"
+	"github.com/go-kratos/kratos/v2/transport/grpc"
+	"github.com/go-kratos/kratos/v2/transport/http"
+
+	stdgrpc "google.golang.org/grpc"
+	grpcmd "google.golang.org/grpc/metadata"
+)
+
+func main() {
+	callHTTP()
+	callGRPC()
+}
+
+func callHTTP() {
+	conn, err := http.NewClient(
+		context.Background(),
+		http.WithEndpoint("127.0.0.1:8000"),
+	)
+	if err != nil {
+		panic(err)
+	}
+	client := helloworld.NewGreeterHTTPClient(conn)
+	ctx := context.Background()
+	var header stdhttp.Header
+	reply, err := client.SayHello(ctx, &helloworld.HelloRequest{Name: "kratos"}, http.Header(&header))
+	if err != nil {
+		log.Fatal(err)
+	}
+	log.Printf("[http] SayHello %s header: %v\n", reply.Message, header)
+}
+
+func callGRPC() {
+	conn, err := grpc.DialInsecure(
+		context.Background(),
+		grpc.WithEndpoint("127.0.0.1:9000"),
+	)
+	if err != nil {
+		log.Fatal(err)
+	}
+	client := helloworld.NewGreeterClient(conn)
+	ctx := context.Background()
+	var md grpcmd.MD
+	reply, err := client.SayHello(ctx, &helloworld.HelloRequest{Name: "kratos"}, stdgrpc.Header(&md))
+	if err != nil {
+		log.Fatal(err)
+	}
+	log.Printf("[grpc] SayHello %+v header: %v\n", reply, md)
+}

examples/header/server/main.go

@@ -0,0 +1,60 @@
+package main
+
+import (
+	"context"
+	"fmt"
+	"log"
+
+	"github.com/go-kratos/kratos/examples/helloworld/helloworld"
+	"github.com/go-kratos/kratos/v2"
+	"github.com/go-kratos/kratos/v2/transport"
+	"github.com/go-kratos/kratos/v2/transport/grpc"
+	"github.com/go-kratos/kratos/v2/transport/http"
+)
+
+// go build -ldflags "-X main.Version=x.y.z"
+var (
+	// Name is the name of the compiled software.
+	Name = "helloworld"
+	// Version is the version of the compiled software.
+	Version = "v1.0.0"
+)
+
+// server is used to implement helloworld.GreeterServer.
+type server struct {
+	helloworld.UnimplementedGreeterServer
+}
+
+// SayHello implements helloworld.GreeterServer
+func (s *server) SayHello(ctx context.Context, in *helloworld.HelloRequest) (*helloworld.HelloReply, error) {
+	info, _ := kratos.FromContext(ctx)
+	if tr, ok := transport.FromServerContext(ctx); ok {
+		tr.ReplyHeader().Set("app_name", info.Name())
+	}
+	return &helloworld.HelloReply{Message: fmt.Sprintf("Hello %s", in.Name)}, nil
+}
+
+func main() {
+	grpcSrv := grpc.NewServer(
+		grpc.Address(":9000"),
+	)
+	httpSrv := http.NewServer(
+		http.Address(":8000"),
+	)
+
+	s := &server{}
+	helloworld.RegisterGreeterServer(grpcSrv, s)
+	helloworld.RegisterGreeterHTTPServer(httpSrv, s)
+
+	app := kratos.New(
+		kratos.Name(Name),
+		kratos.Server(
+			httpSrv,
+			grpcSrv,
+		),
+	)
+
+	if err := app.Run(); err != nil {
+		log.Fatal(err)
+	}
+}

examples/metadata/client/main.go

@@ -34,7 +34,7 @@ func callHTTP() {
 	if err != nil {
 		log.Fatal(err)
 	}
-	log.Printf("[http] SayHello %s\n", reply.Message)
+	log.Printf("[http] SayHello %s\n", reply)
 }
 
 func callGRPC() {
@@ -55,5 +55,5 @@ func callGRPC() {
 	if err != nil {
 		log.Fatal(err)
 	}
-	log.Printf("[grpc] SayHello %+v\n", reply)
+	log.Printf("[grpc] SayHello %+v \n", reply)
 }

examples/metadata/server/main.go

@@ -32,8 +32,7 @@ func (s *server) SayHello(ctx context.Context, in *helloworld.HelloRequest) (*he
 	if md, ok := metadata.FromServerContext(ctx); ok {
 		extra = md.Get("x-md-global-extra")
 	}
-	info, _ := kratos.FromContext(ctx)
-	return &helloworld.HelloReply{Message: fmt.Sprintf("Hello %s extra: %s name: %s", in.Name, extra, info.Name())}, nil
+	return &helloworld.HelloReply{Message: fmt.Sprintf("Hello %s extra_meta: %s", in.Name, extra)}, nil
 }
 
 func main() {