fix:issue-5110 (#5113)

gateway/internal/eventhandler.go

@@ -1,6 +1,7 @@
 package internal
 
 import (
+	"fmt"
 	"io"
 	"net/http"
 
@@ -12,6 +13,22 @@ import (
 	"google.golang.org/grpc/status"
 )
 
+// MetadataHeaderPrefix is the http prefix that represents custom metadata
+// parameters to or from a gRPC call.
+const MetadataHeaderPrefix = "Grpc-Metadata-"
+
+// MetadataTrailerPrefix is prepended to gRPC metadata as it is converted to
+// HTTP headers in a response handled by go-zero gateway
+const MetadataTrailerPrefix = "Grpc-Trailer-"
+
+func defaultOutgoingHeaderMatcher(key string) (string, bool) {
+	return fmt.Sprintf("%s%s", MetadataHeaderPrefix, key), true
+}
+
+func defaultOutgoingTrailerMatcher(key string) (string, bool) {
+	return fmt.Sprintf("%s%s", MetadataTrailerPrefix, key), true
+}
+
 type EventHandler struct {
 	Status    *status.Status
 	writer    io.Writer
@@ -31,9 +48,11 @@ func NewEventHandler(writer io.Writer, resolver jsonpb.AnyResolver) *EventHandle
 func (h *EventHandler) OnReceiveHeaders(md metadata.MD) {
 	w, ok := h.writer.(http.ResponseWriter)
 	if ok {
-		for k, v := range md {
-			for _, val := range v {
-				w.Header().Add(k, val)
+		for k, vs := range md {
+			if h, ok := defaultOutgoingHeaderMatcher(k); ok {
+				for _, v := range vs {
+					w.Header().Add(h, v)
+				}
 			}
 		}
 	}
@@ -48,9 +67,11 @@ func (h *EventHandler) OnReceiveResponse(message proto.Message) {
 func (h *EventHandler) OnReceiveTrailers(status *status.Status, md metadata.MD) {
 	w, ok := h.writer.(http.ResponseWriter)
 	if ok {
-		for k, v := range md {
-			for _, val := range v {
-				w.Header().Add(k, val)
+		for k, vs := range md {
+			if h, ok := defaultOutgoingTrailerMatcher(k); ok {
+				for _, v := range vs {
+					w.Header().Add(h, v)
+				}
 			}
 		}
 	}

gateway/internal/eventhandler_test.go

@@ -40,8 +40,8 @@ func TestEventHandler_OnReceiveTrailers(t *testing.T) {
 			},
 			expectedStatus: codes.OK,
 			expectedHeader: map[string][]string{
-				"X-Custom-Header":  {"value1", "value2"},
-				"X-Another-Header": {"single-value"},
+				"Grpc-Trailer-X-Custom-Header":  {"value1", "value2"},
+				"Grpc-Trailer-X-Another-Header": {"single-value"},
 			},
 		},
 		{
@@ -100,9 +100,9 @@ func TestEventHandler_OnReceiveHeaders(t *testing.T) {
 				"x-another-header": []string{"single-value"},
 			},
 			expectedHeader: map[string][]string{
-				"Content-Type":     {"application/json"},
-				"X-Custom-Header":  {"value1", "value2"},
-				"X-Another-Header": {"single-value"},
+				"Grpc-Metadata-Content-Type":     {"application/json"},
+				"Grpc-Metadata-X-Custom-Header":  {"value1", "value2"},
+				"Grpc-Metadata-X-Another-Header": {"single-value"},
 			},
 		},
 		{
@@ -158,7 +158,81 @@ func TestEventHandler_OnReceiveHeaders_MultipleValues(t *testing.T) {
 		"x-header-2": []string{"value3"},
 	})
 	
-	// Check that headers are accumulated (not overwritten)
-	assert.Equal(t, []string{"value1", "value2"}, recorder.Header()["X-Header-1"])
-	assert.Equal(t, []string{"value3"}, recorder.Header()["X-Header-2"])
+	// Check that headers are accumulated (not overwritten) with proper prefix
+	assert.Equal(t, []string{"value1", "value2"}, recorder.Header()["Grpc-Metadata-X-Header-1"])
+	assert.Equal(t, []string{"value3"}, recorder.Header()["Grpc-Metadata-X-Header-2"])
+}
+
+func TestEventHandler_OnReceiveHeaders_MetadataPrefix(t *testing.T) {
+	tests := []struct {
+		name           string
+		metadata       metadata.MD
+		expectedHeader map[string][]string
+	}{
+		{
+			name: "all metadata headers should be prefixed with Grpc-Metadata-",
+			metadata: metadata.MD{
+				"content-type":    []string{"application/grpc"},
+				"x-custom-header": []string{"value1"},
+				"authorization":   []string{"Bearer token"},
+			},
+			expectedHeader: map[string][]string{
+				"Grpc-Metadata-Content-Type":    {"application/grpc"},
+				"Grpc-Metadata-X-Custom-Header": {"value1"},
+				"Grpc-Metadata-Authorization":   {"Bearer token"},
+			},
+		},
+		{
+			name: "mixed case headers should be prefixed",
+			metadata: metadata.MD{
+				"Content-Type":    []string{"APPLICATION/JSON"},
+				"X-Custom-Header": []string{"value1"},
+			},
+			expectedHeader: map[string][]string{
+				"Grpc-Metadata-Content-Type":    {"APPLICATION/JSON"},
+				"Grpc-Metadata-X-Custom-Header": {"value1"},
+			},
+		},
+		{
+			name: "multiple values for same header",
+			metadata: metadata.MD{
+				"x-multi-header": []string{"value1", "value2", "value3"},
+			},
+			expectedHeader: map[string][]string{
+				"Grpc-Metadata-X-Multi-Header": {"value1", "value2", "value3"},
+			},
+		},
+		{
+			name: "empty metadata",
+			metadata: metadata.MD{},
+			expectedHeader: map[string][]string{},
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			recorder := httptest.NewRecorder()
+			h := NewEventHandler(recorder, nil)
+			
+			h.OnReceiveHeaders(tt.metadata)
+			
+			// Check that headers are set correctly
+			for key, expectedValues := range tt.expectedHeader {
+				actualValues := recorder.Header()[key]
+				assert.Equal(t, expectedValues, actualValues, "Header %s should match", key)
+			}
+			
+			// Ensure no unexpected headers are set
+			for actualKey := range recorder.Header() {
+				found := false
+				for expectedKey := range tt.expectedHeader {
+					if actualKey == expectedKey {
+						found = true
+						break
+					}
+				}
+				assert.True(t, found, "Unexpected header found: %s", actualKey)
+			}
+		})
+	}
 }