package main import ( "context" "github.com/yuin/gopher-lua" "log" "net/http" "time" ) //type and value to store user in lua's Context type key int const ( userContextKey key = iota accountsContextKey securitiesContextKey balanceContextKey ) const luaTimeoutSeconds time.Duration = 5 // maximum time a lua request can run for func ReportHandler(w http.ResponseWriter, r *http.Request) { user, err := GetUserFromSession(r) if err != nil { WriteError(w, 1 /*Not Signed In*/) return } if r.Method == "GET" { // Create a new LState without opening the default libs for security L := lua.NewState(lua.Options{SkipOpenLibs: true}) defer L.Close() // Create a new context holding the current user with a timeout ctx := context.WithValue(context.Background(), userContextKey, user) ctx, cancel := context.WithTimeout(ctx, luaTimeoutSeconds*time.Second) defer cancel() L.SetContext(ctx) for _, pair := range []struct { n string f lua.LGFunction }{ {lua.LoadLibName, lua.OpenPackage}, // Must be first {lua.BaseLibName, lua.OpenBase}, {lua.TabLibName, lua.OpenTable}, {lua.StringLibName, lua.OpenString}, {lua.MathLibName, lua.OpenMath}, } { if err := L.CallByParam(lua.P{ Fn: L.NewFunction(pair.f), NRet: 0, Protect: true, }, lua.LString(pair.n)); err != nil { panic(err) } } luaRegisterAccounts(L) luaRegisterSecurities(L) luaRegisterBalances(L) err := L.DoString(`accounts = account.get_all() last_parent = nil for id, account in pairs(accounts) do parent = account.parent print(account, parent, account.security) if parent then print(last_parent, parent) print("parent equals last:", last_parent == parent) last_parent = parent end end `) if err != nil { log.Print("lua:" + err.Error()) } } }