feat(config): add HTTP2 field to ServerInstanceConfig and align with server.Config

* change Content-Range format to include 'items'
* add X-Api-Range-From and X-Api-Modelname headers
* add X-Api-Range-Etotal header for total filtered items

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/restheadspec/handler.go

@@ -2711,9 +2711,12 @@ func (h *Handler) sendFormattedResponse(w common.ResponseWriter, data interface{
 	}
 
 	w.SetHeader("Content-Type", "application/json")
-	w.SetHeader("Content-Range", fmt.Sprintf("%d-%d/%d", metadata.Offset, int64(metadata.Offset)+metadata.Count, metadata.Filtered))
+	w.SetHeader("Content-Range", fmt.Sprintf("items %d-%d/%d", metadata.Offset, int64(metadata.Offset)+metadata.Count, metadata.Filtered))
 	w.SetHeader("X-Api-Range-Total", fmt.Sprintf("%d", metadata.Filtered))
 	w.SetHeader("X-Api-Range-Size", fmt.Sprintf("%d", metadata.Count))
+	w.SetHeader("X-Api-Range-From", fmt.Sprintf("%d", metadata.Offset))
+	w.SetHeader("X-Api-Range-Etotal", fmt.Sprintf("%d", metadata.Filtered))
+	w.SetHeader("X-Api-Modelname", tableName)
 
 	// Format response based on response format option
 	switch options.ResponseFormat {

pkg/restheadspec/headers.go

@@ -225,12 +225,13 @@ func (h *Handler) parseOptionsFromHeaders(r common.Request, model interface{}) E
 			limitValueParts := strings.Split(limitValue, ",")
 
 			if len(limitValueParts) > 1 {
-				if offset, err := strconv.Atoi(limitValueParts[0]); err == nil {
-					options.Offset = &offset
-				}
-				if limit, err := strconv.Atoi(limitValueParts[1]); err == nil {
+				if limit, err := strconv.Atoi(limitValueParts[0]); err == nil {
 					options.Limit = &limit
 				}
+				if offset, err := strconv.Atoi(limitValueParts[1]); err == nil {
+					options.Offset = &offset
+				}
+
 			} else {
 				if limit, err := strconv.Atoi(limitValueParts[0]); err == nil {
 					options.Limit = &limit

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

pkg/server/manager.go

@@ -8,6 +8,7 @@ import (
 	"net/http"
 	"os"
 	"os/signal"
+	"strings"
 	"sync"
 	"sync/atomic"
 	"syscall"
@@ -461,15 +462,38 @@ 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 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.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{}),