feat(router): add Lua scripting for routing script

infra/conf/router.go

@@ -7,6 +7,7 @@ import (
 	"github.com/xtls/xray-core/app/router"
 	"github.com/xtls/xray-core/common/errors"
 	"github.com/xtls/xray-core/common/geodata"
+	"github.com/xtls/xray-core/common/platform"
 	"github.com/xtls/xray-core/common/serial"
 
 	"google.golang.org/protobuf/proto"
@@ -72,6 +73,7 @@ type RouterConfig struct {
 	RuleList       []json.RawMessage `json:"rules"`
 	DomainStrategy *string           `json:"domainStrategy"`
 	Balancers      []*BalancingRule  `json:"balancers"`
+	Script         string            `json:"script"`
 }
 
 func (c *RouterConfig) getDomainStrategy() router.Config_DomainStrategy {
@@ -92,6 +94,15 @@ func (c *RouterConfig) getDomainStrategy() router.Config_DomainStrategy {
 
 func (c *RouterConfig) Build() (*router.Config, error) {
 	config := new(router.Config)
+
+	if c.Script != "" {
+		path, err := platform.ResolveLuaFile(c.Script)
+		if err != nil {
+			return nil, errors.New("failed to resolve routing script").Base(err)
+		}
+		config.Script = path
+	}
+
 	config.DomainStrategy = c.getDomainStrategy()
 
 	var rawRuleList []json.RawMessage

infra/conf/router_test.go

@@ -2,6 +2,8 @@ package conf_test
 
 import (
 	"encoding/json"
+	"os"
+	"path/filepath"
 	"testing"
 	"time"
 	_ "unsafe"
@@ -236,3 +238,39 @@ func TestRouterConfig(t *testing.T) {
 		},
 	})
 }
+
+func TestRouterScriptConfig(t *testing.T) {
+	dir := t.TempDir()
+	t.Setenv("xray.location.confdir", dir)
+	path := filepath.Join(dir, "route.lua")
+	if err := os.WriteFile(path, []byte("function HandleRoute() end"), 0o600); err != nil {
+		t.Fatal(err)
+	}
+
+	for _, tc := range []struct {
+		name      string
+		script    string
+		wantError bool
+	}{
+		{"relative", "route.lua", false},
+		{"absolute", path, false},
+		{"missing", "missing.lua", true},
+		{"directory", dir, true},
+	} {
+		t.Run(tc.name, func(t *testing.T) {
+			built, err := (&RouterConfig{Script: tc.script}).Build()
+			if tc.wantError {
+				if err == nil {
+					t.Fatal("Build accepted invalid script path")
+				}
+				return
+			}
+			if err != nil {
+				t.Fatal(err)
+			}
+			if built.Script != path {
+				t.Fatalf("script path = %q, want %q", built.Script, path)
+			}
+		})
+	}
+}