Set up lua GeoIP handler registration and Cloudflare GeoIP header example plugin

pkg/posting/geoip/preload.go

@@ -0,0 +1,125 @@
+package geoip
+
+import (
+	"errors"
+	"net/http"
+
+	"github.com/rs/zerolog"
+	lua "github.com/yuin/gopher-lua"
+	luar "layeh.com/gopher-luar"
+)
+
+type luaHandler struct {
+	lState         *lua.LState
+	initFunc       lua.LValue
+	getCountryFunc lua.LValue
+	closeFunc      lua.LValue
+}
+
+func (lh *luaHandler) Init(options map[string]any) error {
+	if lh.initFunc == lua.LNil {
+		return nil
+	}
+	optionsT := lh.lState.NewTable()
+	for k, v := range options {
+		optionsT.RawSetString(k, luar.New(lh.lState, v))
+	}
+	p := lua.P{
+		Fn:   lh.initFunc,
+		NRet: 1,
+	}
+	err := lh.lState.CallByParam(p, optionsT)
+	if err != nil {
+		return err
+	}
+	errStr := lua.LVAsString(lh.lState.Get(-1))
+	if errStr != "" {
+		return errors.New(errStr)
+	}
+	return nil
+}
+
+func (lh *luaHandler) GetCountry(request *http.Request, board string, errEv *zerolog.Event) (*Country, error) {
+	p := lua.P{
+		Fn:   lh.getCountryFunc,
+		NRet: 2,
+	}
+	err := lh.lState.CallByParam(p,
+		luar.New(lh.lState, request),
+		lua.LString(board),
+		luar.New(lh.lState, errEv))
+
+	if err != nil {
+		return nil, err
+	}
+	countryTable, ok := lh.lState.Get(-2).(*lua.LTable)
+	if !ok {
+		return nil, errors.New("invalid value returned by get_country (expected table)")
+	}
+	errStr := lua.LVAsString(lh.lState.Get(-1))
+	if errStr != "" {
+		return nil, errors.New(errStr)
+	}
+	name, ok := countryTable.RawGetString("name").(lua.LString)
+	if !ok {
+		return nil, errors.New("invalid name value in table returned gy bet_country (expected string)")
+	}
+	flag, ok := countryTable.RawGetString("flag").(lua.LString)
+	if !ok {
+		return nil, errors.New("invalid flag value in table returned gy bet_country (expected string)")
+	}
+	return &Country{
+		Name: name.String(),
+		Flag: flag.String(),
+	}, nil
+}
+
+func (lh *luaHandler) Close() error {
+	if lh.closeFunc == lua.LNil {
+		return nil
+	}
+	p := lua.P{
+		Fn:   lh.closeFunc,
+		NRet: 1,
+	}
+	err := lh.lState.CallByParam(p)
+	if err != nil {
+		return err
+	}
+	errStr := lua.LVAsString(lh.lState.Get(-1))
+	if errStr != "" {
+		return errors.New(errStr)
+	}
+	return nil
+}
+
+func PreloadModule(l *lua.LState) int {
+	t := l.NewTable()
+	l.SetFuncs(t, map[string]lua.LGFunction{
+		"register_handler": func(l *lua.LState) int {
+			name := l.CheckString(1)
+			handlerTable := l.CheckTable(2)
+			initFuncVal := handlerTable.RawGetString("init")
+			lookupFunc := handlerTable.RawGetString("get_country")
+			closeFuncVal := handlerTable.RawGetString("close")
+			handler := &luaHandler{
+				lState:         l,
+				initFunc:       initFuncVal,
+				getCountryFunc: lookupFunc,
+				closeFunc:      closeFuncVal,
+			}
+
+			RegisterGeoIPHandler(name, handler)
+			return 0
+		},
+		"country_name": func(l *lua.LState) int {
+			abbr := l.CheckString(1)
+			name, err := GetCountryName(abbr)
+			l.Push(lua.LString(name))
+			l.Push(luar.New(l, err))
+			return 2
+		},
+	})
+	l.Push(t)
+	return 1
+}