fix(cors): update CORS headers handling for requests

* Reflect request origin for Access-Control-Allow-Origin
* Set Vary header for caching based on origin
* Allow specific headers from preflight requests
* Enable credentials only for specific origins

pkg/common/cors.go

@@ -115,32 +115,39 @@ func GetHeadSpecHeaders() []string {
 
 // SetCORSHeaders sets CORS headers on a response writer
 func SetCORSHeaders(w ResponseWriter, r Request, config CORSConfig) {
-	// Set allowed origins
-	// if len(config.AllowedOrigins) > 0 {
-	// 	w.SetHeader("Access-Control-Allow-Origin", strings.Join(config.AllowedOrigins, ", "))
-	// }
-
-	// Todo origin list parsing
-	w.SetHeader("Access-Control-Allow-Origin", "*")
+	// Reflect the request origin; fall back to wildcard only when no origin is present
+	origin := r.Header("Origin")
+	if origin == "" {
+		origin = "*"
+	} else {
+		// Vary must be set so caches don't serve one origin's response to another
+		httpW := w.UnderlyingResponseWriter()
+		httpW.Header().Set("Vary", "Origin")
+	}
+	w.SetHeader("Access-Control-Allow-Origin", origin)
 
 	// Set allowed methods
 	if len(config.AllowedMethods) > 0 {
 		w.SetHeader("Access-Control-Allow-Methods", strings.Join(config.AllowedMethods, ", "))
 	}
 
-	// Set allowed headers
-	// if len(config.AllowedHeaders) > 0 {
-	// 	w.SetHeader("Access-Control-Allow-Headers", strings.Join(config.AllowedHeaders, ", "))
-	// }
-	w.SetHeader("Access-Control-Allow-Headers", "*")
+	// Reflect the preflight request headers when present; otherwise use the explicit config list
+	requestedHeaders := r.Header("Access-Control-Request-Headers")
+	if requestedHeaders != "" {
+		w.SetHeader("Access-Control-Allow-Headers", requestedHeaders)
+	} else if len(config.AllowedHeaders) > 0 {
+		w.SetHeader("Access-Control-Allow-Headers", strings.Join(config.AllowedHeaders, ", "))
+	}
 
 	// Set max age
 	if config.MaxAge > 0 {
 		w.SetHeader("Access-Control-Max-Age", fmt.Sprintf("%d", config.MaxAge))
 	}
 
-	// Allow credentials
-	w.SetHeader("Access-Control-Allow-Credentials", "true")
+	// Allow credentials only when a specific origin is reflected (not wildcard)
+	if origin != "*" {
+		w.SetHeader("Access-Control-Allow-Credentials", "true")
+	}
 
 	// Expose headers that clients can read
 	exposeHeaders := config.AllowedHeaders

pkg/config/config.go

@@ -50,6 +50,10 @@ type ServerInstanceConfig struct {
 	// GZIP enables GZIP compression middleware
 	GZIP bool `mapstructure:"gzip"`
 
+	// HTTP2 enables HTTP/2 with the Extended CONNECT protocol (RFC 8441) for WebSocket support.
+	// Requires TLS; pair with SSLCert/SSLKey, SelfSignedSSL, or AutoTLS.
+	HTTP2 bool `mapstructure:"http2"`
+
 	// TLS/HTTPS configuration options (mutually exclusive)
 	// Option 1: Provide certificate and key files directly
 	SSLCert string `mapstructure:"ssl_cert"`

pkg/server/config_helper.go

@@ -16,6 +16,7 @@ func FromConfigInstanceToServerConfig(sic *config.ServerInstanceConfig, handler
 		Description: sic.Description,
 		Handler:     handler,
 		GZIP:        sic.GZIP,
+		HTTP2:       sic.HTTP2,
 
 		SSLCert:         sic.SSLCert,
 		SSLKey:          sic.SSLKey,

pkg/server/interfaces.go

@@ -19,6 +19,10 @@ type Config struct {
 	// GZIP compression support
 	GZIP bool
 
+	// HTTP2 enables HTTP/2 with the Extended CONNECT protocol (RFC 8441) for WebSocket support.
+	// Requires TLS; pair with SSLCert/SSLKey, SelfSignedSSL, or AutoTLS.
+	HTTP2 bool
+
 	// TLS/HTTPS configuration options (mutually exclusive)
 	// Option 1: Provide certificate and key files directly
 	SSLCert string
@@ -38,6 +42,10 @@ type Config struct {
 	// AutoTLSEmail is the email for Let's Encrypt registration (optional but recommended)
 	AutoTLSEmail string
 
+	// PanicHandler is called when a request handler panics.
+	// If nil, the default middleware.PanicRecovery is used (logs, records metric, returns 500).
+	PanicHandler func(w http.ResponseWriter, r *http.Request, rcv any)
+
 	// Graceful shutdown configuration
 	// ShutdownTimeout is the maximum time to wait for graceful shutdown
 	// Default: 30 seconds

pkg/server/manager.go

@@ -8,6 +8,7 @@ import (
 	"net/http"
 	"os"
 	"os/signal"
+	"strings"
 	"sync"
 	"sync/atomic"
 	"syscall"
@@ -451,8 +452,19 @@ func newInstance(cfg Config) (*serverInstance, error) {
 		handler = gz(handler)
 	}
 
-	// Wrap with the panic recovery middleware
-	handler = middleware.PanicRecovery(handler)
+	// Wrap with panic recovery — use caller-supplied handler if provided
+	if cfg.PanicHandler != nil {
+		handler = http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+			defer func() {
+				if rcv := recover(); rcv != nil {
+					cfg.PanicHandler(w, r, rcv)
+				}
+			}()
+			handler.ServeHTTP(w, r)
+		})
+	} else {
+		handler = middleware.PanicRecovery(handler)
+	}
 
 	// Configure TLS if any TLS option is enabled
 	tlsConfig, certFile, keyFile, err := configureTLS(cfg)
@@ -461,15 +473,43 @@ func newInstance(cfg Config) (*serverInstance, error) {
 	}
 
 	// Create gracefulServer
+	httpServer := &http.Server{
+		Addr:         addr,
+		Handler:      handler,
+		ReadTimeout:  cfg.ReadTimeout,
+		WriteTimeout: cfg.WriteTimeout,
+		IdleTimeout:  cfg.IdleTimeout,
+		TLSConfig:    tlsConfig,
+	}
+
+	// Enable HTTP/2 with Extended CONNECT (RFC 8441) for WebSocket-over-H2 support.
+	// The GODEBUG=http2xconnect=1 flag is read by net/http's init(); setting it here
+	// ensures it propagates to subprocesses and any future process restarts.
+	// For the current process, set GODEBUG=http2xconnect=1 in the environment before launch.
+	if httpServer.Protocols == nil {
+		httpServer.Protocols = &http.Protocols{}
+		httpServer.Protocols.SetHTTP1(true)
+	}
+	if cfg.HTTP2 {
+		if existing := os.Getenv("GODEBUG"); !strings.Contains(existing, "http2xconnect=1") {
+			if existing == "" {
+				os.Setenv("GODEBUG", "http2xconnect=1")
+			} else {
+				os.Setenv("GODEBUG", existing+",http2xconnect=1")
+			}
+		}
+		if httpServer.HTTP2 == nil {
+			httpServer.HTTP2 = &http.HTTP2Config{}
+		}
+		httpServer.Protocols.SetHTTP2(true)
+		httpServer.Protocols.SetUnencryptedHTTP2(true)
+	} else {
+		httpServer.Protocols.SetHTTP1(true)
+		httpServer.Protocols.SetHTTP2(false)
+	}
+
 	gracefulSrv := &gracefulServer{
-		server: &http.Server{
-			Addr:         addr,
-			Handler:      handler,
-			ReadTimeout:  cfg.ReadTimeout,
-			WriteTimeout: cfg.WriteTimeout,
-			IdleTimeout:  cfg.IdleTimeout,
-			TLSConfig:    tlsConfig,
-		},
+		server:           httpServer,
 		shutdownTimeout:  cfg.ShutdownTimeout,
 		drainTimeout:     cfg.DrainTimeout,
 		shutdownComplete: make(chan struct{}),