make /api/ h2c compatible

backend/go.mod

@@ -9,6 +9,7 @@ require (
 	github.com/improbable-eng/grpc-web v0.15.0
 	github.com/pkg/errors v0.9.1
 	github.com/sirupsen/logrus v1.9.3
+	golang.org/x/net v0.9.0
 	golang.org/x/sys v0.10.0
 	google.golang.org/grpc v1.56.2
 	google.golang.org/protobuf v1.31.0
@@ -45,7 +46,6 @@ require (
 	github.com/rs/cors v1.7.0 // indirect
 	github.com/sasha-s/go-deadlock v0.3.1 // indirect
 	github.com/spf13/pflag v1.0.6-0.20200504143853-81378bbcd8a1 // indirect
-	golang.org/x/net v0.9.0 // indirect
 	golang.org/x/oauth2 v0.7.0 // indirect
 	golang.org/x/sync v0.1.0 // indirect
 	golang.org/x/term v0.7.0 // indirect

backend/main.go

@@ -14,6 +14,8 @@ import (
 	gops "github.com/google/gops/agent"
 	"github.com/improbable-eng/grpc-web/go/grpcweb"
 	"github.com/sirupsen/logrus"
+	"golang.org/x/net/http2"
+	"golang.org/x/net/http2/h2c"
 	"golang.org/x/sys/unix"
 	"google.golang.org/grpc"
 
@@ -55,6 +57,7 @@ func runServer(cfg *config.Config) {
 		req.URL.Path = req.URL.Path[len("/api/"):]
 		wrappedGrpc.ServeHTTP(resp, req)
 	})
+	h2cHandler := h2c.NewHandler(handler, &http2.Server{})
 
 	ctx, cancel := signal.NotifyContext(context.Background(), unix.SIGINT, unix.SIGTERM)
 	defer cancel()
@@ -63,7 +66,7 @@ func runServer(cfg *config.Config) {
 
 	httpSrv := &http.Server{
 		Addr:    addr,
-		Handler: handler,
+		Handler: h2cHandler,
 		BaseContext: func(net.Listener) context.Context {
 			return ctx
 		},

backend/vendor/modules.txt

@@ -135,6 +135,7 @@ github.com/spf13/pflag
 golang.org/x/net/context
 golang.org/x/net/http/httpguts
 golang.org/x/net/http2
+golang.org/x/net/http2/h2c
 golang.org/x/net/http2/hpack
 golang.org/x/net/idna
 golang.org/x/net/internal/timeseries