Add anti-buffering relay headers and optional randomized query suffixes

internal/server/server.go

@@ -107,6 +107,8 @@ func (s *Server) Run(ctx context.Context) error {
 }
 
 func (s *Server) handleRelay(w http.ResponseWriter, r *http.Request) {
+	applyRelayResponseHeaders(w.Header())
+
 	if r.Method != http.MethodPost {
 		http.Error(w, "method not allowed", http.StatusMethodNotAllowed)
 		return
@@ -167,6 +169,13 @@ func (s *Server) handleRelay(w http.ResponseWriter, r *http.Request) {
 	_, _ = w.Write(encrypted)
 }
 
+func applyRelayResponseHeaders(header http.Header) {
+	header.Set("Cache-Control", "no-store, no-cache, must-revalidate")
+	header.Set("Pragma", "no-cache")
+	header.Set("Expires", "0")
+	header.Set("X-Accel-Buffering", "no")
+}
+
 func (s *Server) processBatch(batch protocol.Batch) (protocol.Batch, error) {
 	session := s.getOrCreateSession(batch.ClientSessionKey)
 	now := time.Now()

internal/server/server_test.go

@@ -3,6 +3,7 @@ package server
 import (
 	"errors"
 	"net"
+	"net/http/httptest"
 	"sync"
 	"testing"
 	"time"
@@ -319,6 +320,27 @@ func TestSOCKSStateCloseUpstreamClearsConnectionSnapshot(t *testing.T) {
 	}
 }
 
+func TestHandleRelayAppliesAntiBufferingHeaders(t *testing.T) {
+	srv := New(config.Config{}, nil)
+	request := httptest.NewRequest("GET", "/relay", nil)
+	recorder := httptest.NewRecorder()
+
+	srv.handleRelay(recorder, request)
+
+	if got := recorder.Header().Get("X-Accel-Buffering"); got != "no" {
+		t.Fatalf("expected X-Accel-Buffering=no, got %q", got)
+	}
+	if got := recorder.Header().Get("Cache-Control"); got != "no-store, no-cache, must-revalidate" {
+		t.Fatalf("unexpected Cache-Control header: %q", got)
+	}
+	if got := recorder.Header().Get("Pragma"); got != "no-cache" {
+		t.Fatalf("unexpected Pragma header: %q", got)
+	}
+	if got := recorder.Header().Get("Expires"); got != "0" {
+		t.Fatalf("unexpected Expires header: %q", got)
+	}
+}
+
 func testDataPacket(clientSessionKey string, socksID uint64, sequence uint64, payload string) protocol.Packet {
 	packet := protocol.NewPacket(clientSessionKey, protocol.PacketTypeSOCKSData)
 	packet.SOCKSID = socksID