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Access-Control-Expose-Headers errors in browser when response from server

See original GitHub issue

Hi,

I’m playing with grpc-web and maybe I’m doing something wrong, but I’m geting this:

I’m sucessfully recieved request on server with all data… but response end with this errors in browser (Chrome) 😦

My test code:

I create good request from my js client:

import { RegistrationServicePromiseClient, RegistrationServiceClient, Data } from '~/api/registration_grpc_web_pb.js'

...

var data = new Data()
data.setEmail("test@example.com")
data.setPassword("abcd")
var client = new RegistrationServiceClient("https://localhost:8000")
client.newRegistration(data,null,(res) => {
    console.log("res:",res)
})

and on my golang server (in main func):

func main() {
	creds, err := credentials.NewServerTLSFromFile("localhost.pem", "localhost-key.pem")
	if err != nil {
		fmt.Print(err)
	}

	grpcServer := grpc.NewServer(grpc.Creds(creds))
	wrappedGrpc := grpcweb.WrapServer(grpcServer, grpcweb.WithAllowedRequestHeaders([]string{"*"}), grpcweb.WithWebsockets(false))

	srv := TestService{}
	protos.RegisterRegistrationServiceServer(grpcServer, &srv)

	handler := http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		w.Header().Set("Access-Control-Allow-Origin", "*")
		w.Header().Set("Access-Control-Allow-Methods", "POST, GET, OPTIONS, PUT, DELETE")
		w.Header().Set("Access-Control-Allow-Headers", "Accept, Content-Type, Content-Length, Accept-Encoding, X-CSRF-Token, Authorization, x-user-agent, x-grpc-web, grpc-status, grpc-message")
		w.Header().Set("Access-Control-Expose-Headers", "grpc-status, grpc-message")
		if r.Method == "OPTIONS" {
			return
		}

		if wrappedGrpc.IsGrpcWebRequest(r) {
			wrappedGrpc.ServeHTTP(w, r)
		} else {
			// Fall back to other servers.
			http.DefaultServeMux.ServeHTTP(w, r)
		}
	})

	httpserver := http.Server{
		Addr:           ":8000",
		Handler:        handler,
		ReadTimeout:    10 * time.Second,
		WriteTimeout:   10 * time.Second,
		MaxHeaderBytes: 1 << 20,
	}
	http2.ConfigureServer(&httpserver, nil)

	err = httpserver.ListenAndServeTLS("localhost.pem", "localhost-key.pem")
	if err != nil {
		panic(err)
	}
}

func (ser *TestService) NewRegistration(ctx context.Context, data *protos.Data) (*protos.Response, error) {

	fmt.Printf("RECIEVED: %v\n", data)

	res := protos.Response{}
	res.Status = 123
	res.Message = "Test"

	return &res, nil
}

Verion grpc-web: 0.9.1

thanks for any help…