go grpc custom interceptor

proto file

syntax = "proto3";import "google/protobuf/timestamp.proto";package pb;option go_package = "./pb";serviceToDoService {rpc DoWork (TodoRequest) returns (TodoResponse);}enum Week {Sunday = 0;Monday = 1;Tuesday = 2;Wednesday = 3;Thursday = 4;Friday = 5;Saturday = 6;}message TodoRequest{string todo = 1;Week week = 2;map  bookMap = 3; // BookMap map[string]stringgoogle.protobuf.Timestamp doneTime = 4;}message TodoResponse {bool done = 1;}

Generate grpc file

protoc user.proto --go_out=./ --go-grpc_out=./ --go-grpc_opt=require_unimplemented_servers=false

Server

package mainimport ("context""fmt""google.golang.org/grpc""google.golang.org/grpc/codes""google.golang.org/grpc/metadata""google.golang.org/grpc/status""grpc_enum/pb""net""time")//custom interceptorfunc MyInterceptor (ctx context.Context, req interface{}, info *grpc.UnaryServerInfo, handler grpc.UnaryHandler) (resp interface{}, err error){// get data from contextmd, ok := metadata.FromIncomingContext(ctx)if !ok {fmt.Println("Interceptor: metadata nil")return nil,status.Error(codes.Unauthenticated, "Authentication failed [metadata]")}token , ok := md["token"]if !ok {fmt.Println("Interceptor: token nil")return nil,status.Error(codes.Unauthenticated, "Authentication failed [token]")}fmt.Println("token:",token)now := time.Now()resp, err = handler(ctx, req) //The previous one is executed first; the following last execution is similar to the next() middleware in ginfmt.Println("req:",req)lastTime := time.Now().Sub(now)fmt.Println("Execution time: ",lastTime.Milliseconds())return}type TodoInfo struct{}func (t *TodoInfo)DoWork(ctx context.Context, td_req *pb.TodoRequest) (*pb.TodoResponse, error) {//Accept the context parametermd, ok := metadata.FromIncomingContext(ctx)if !ok {fmt.Println("metadata false")}for k,v := range md {fmt.Println("k:",k,"== v:",v)}fmt.Println(td_req.Todo)fmt.Println(td_req.Week)return &pb.TodoResponse{Done: true,}, nil}func main() {//register interceptorserviceOption := grpc.UnaryInterceptor(MyInterceptor)//Instantiate grpcgrpcServer := grpc.NewServer(serviceOption)// register servicepb.RegisterToDoServiceServer(grpcServer,&TodoInfo{})listen,err := net.Listen("tcp", "127.0.0.1:8081")if err != nil {panic(err)}err = grpcServer.Serve(listen)if err != nil {println(err)}}

Client

package mainimport ("context""fmt""google.golang.org/grpc""google.golang.org/grpc/metadata""grpc_enum/pb")//Inherit PerRPCCredentials to implement authentication//Override GetRequestMetadata and RequireTransportSecuritytype MyCredentials struct{}func (c *MyCredentials)GetRequestMetadata(ctx context.Context, uri ...string)(map[string]string, error){return map[string]string{"token":"123456897",}, nil}func (c *MyCredentials)RequireTransportSecurity()bool{return false}func main() {//interceptor//clientInterceptor := func(ctx context.Context, method string, req, reply interface{}, cc *grpc.ClientConn, invoker grpc.UnaryInvoker, opts ...grpc.CallOption) error{// md2 := metadata.Pairs("token","99663322poiopui")// ctx = metadata.NewOutgoingContext(context.Background(), md2)//// now := time.Now()// err := invoker(ctx, method, req, reply, cc, opts ...)// lastTime := time.Now().Sub(now)// fmt.Println("Client execution time: ",lastTime.Milliseconds())// return err//}//opt := grpc.WithUnaryInterceptor(clientInterceptor)//authenticationopt := grpc.WithPerRPCCredentials(&MyCredentials{})conn, err := grpc.Dial("127.0.0.1:8081", grpc.WithInsecure(), opt)defer conn.Close()if err != nil {panic(err)}//Instantiate the ToDo serviceclient := pb.NewToDoServiceClient(conn)md1 := metadata.New(map[string]string{"name" : "hello grpc",})// pass parameters from contextctx := metadata.NewOutgoingContext(context.Background(), md1)//Call the server-side DoWork methodrep, err := client.DoWork(ctx,&pb.TodoRequest{Todo: "Interceptor",Week: pb.Week_Monday,BookMap: map[string]string{"age" : "20",},//DoneTime: time.Now(),})if err != nil {panic(err)}fmt.Println("rep:",rep)}