| /* |
| * |
| * Copyright 2022 gRPC authors. |
| * |
| * Licensed under the Apache License, Version 2.0 (the "License"); |
| * you may not use this file except in compliance with the License. |
| * You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| * |
| */ |
| |
| // Binary server is an example server. |
| package main |
| |
| import ( |
| "context" |
| "flag" |
| "fmt" |
| "io" |
| "log" |
| "net" |
| |
| "google.golang.org/grpc" |
| "google.golang.org/grpc/codes" |
| "google.golang.org/grpc/metadata" |
| "google.golang.org/grpc/status" |
| |
| pb "google.golang.org/grpc/examples/features/proto/echo" |
| ) |
| |
| var port = flag.Int("port", 50051, "the port to serve on") |
| |
| var errMissingMetadata = status.Errorf(codes.InvalidArgument, "no incoming metadata in rpc context") |
| |
| type server struct { |
| pb.UnimplementedEchoServer |
| } |
| |
| func unaryInterceptor(ctx context.Context, req interface{}, info *grpc.UnaryServerInfo, handler grpc.UnaryHandler) (interface{}, error) { |
| md, ok := metadata.FromIncomingContext(ctx) |
| if !ok { |
| return nil, errMissingMetadata |
| } |
| |
| md.Append("key1", "value1") |
| ctx = metadata.NewIncomingContext(ctx, md) |
| |
| return handler(ctx, req) |
| } |
| |
| func (s *server) UnaryEcho(ctx context.Context, in *pb.EchoRequest) (*pb.EchoResponse, error) { |
| fmt.Printf("--- UnaryEcho ---\n") |
| |
| md, ok := metadata.FromIncomingContext(ctx) |
| if !ok { |
| return nil, status.Errorf(codes.Internal, "UnaryEcho: missing incoming metadata in rpc context") |
| } |
| |
| // Read and print metadata added by the interceptor. |
| if v, ok := md["key1"]; ok { |
| fmt.Printf("key1 from metadata: \n") |
| for i, e := range v { |
| fmt.Printf(" %d. %s\n", i, e) |
| } |
| } |
| |
| return &pb.EchoResponse{Message: in.Message}, nil |
| } |
| |
| type wrappedStream struct { |
| grpc.ServerStream |
| ctx context.Context |
| } |
| |
| func (s *wrappedStream) Context() context.Context { |
| return s.ctx |
| } |
| |
| func streamInterceptor(srv interface{}, ss grpc.ServerStream, info *grpc.StreamServerInfo, handler grpc.StreamHandler) error { |
| md, ok := metadata.FromIncomingContext(ss.Context()) |
| if !ok { |
| return errMissingMetadata |
| } |
| |
| md.Append("key1", "value1") |
| ctx := metadata.NewIncomingContext(ss.Context(), md) |
| |
| return handler(srv, &wrappedStream{ss, ctx}) |
| } |
| |
| func (s *server) BidirectionalStreamingEcho(stream pb.Echo_BidirectionalStreamingEchoServer) error { |
| fmt.Printf("--- BidirectionalStreamingEcho ---\n") |
| |
| md, ok := metadata.FromIncomingContext(stream.Context()) |
| if !ok { |
| return status.Errorf(codes.Internal, "BidirectionalStreamingEcho: missing incoming metadata in rpc context") |
| } |
| |
| // Read and print metadata added by the interceptor. |
| if v, ok := md["key1"]; ok { |
| fmt.Printf("key1 from metadata: \n") |
| for i, e := range v { |
| fmt.Printf(" %d. %s\n", i, e) |
| } |
| } |
| |
| // Read requests and send responses. |
| for { |
| in, err := stream.Recv() |
| if err == io.EOF { |
| return nil |
| } |
| if err != nil { |
| return err |
| } |
| if err = stream.Send(&pb.EchoResponse{Message: in.Message}); err != nil { |
| return err |
| } |
| } |
| } |
| |
| func main() { |
| flag.Parse() |
| lis, err := net.Listen("tcp", fmt.Sprintf(":%d", *port)) |
| if err != nil { |
| log.Fatalf("net.Listen() failed: %v", err) |
| } |
| fmt.Printf("Server listening at %v\n", lis.Addr()) |
| |
| s := grpc.NewServer(grpc.UnaryInterceptor(unaryInterceptor), grpc.StreamInterceptor(streamInterceptor)) |
| pb.RegisterEchoServer(s, &server{}) |
| s.Serve(lis) |
| } |