package main import ( "context" "encoding/json" "errors" "github.com/yuin/gopher-lua" "log" "net/http" "os" "path" "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 type Series struct { Values []float64 Series map[string]*Series } type Report struct { ReportId string Title string Subtitle string XAxisLabel string YAxisLabel string Labels []string Series map[string]*Series } func (r *Report) Write(w http.ResponseWriter) error { enc := json.NewEncoder(w) return enc.Encode(r) } func runReport(user *User, reportpath string) (*Report, error) { // 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 { return nil, errors.New("Error initializing Lua packages") } } luaRegisterAccounts(L) luaRegisterSecurities(L) luaRegisterBalances(L) luaRegisterDates(L) luaRegisterReports(L) err := L.DoFile(reportpath) if err != nil { return nil, err } if err := L.CallByParam(lua.P{ Fn: L.GetGlobal("generate"), NRet: 1, Protect: true, }); err != nil { return nil, err } value := L.Get(-1) if ud, ok := value.(*lua.LUserData); ok { if report, ok := ud.Value.(*Report); ok { return report, nil } else { return nil, errors.New("generate() in " + reportpath + " didn't return a report") } } else { return nil, errors.New("generate() in " + reportpath + " didn't return a report") } } 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" { var reportname string n, err := GetURLPieces(r.URL.Path, "/report/%s", &reportname) if err != nil || n != 1 { WriteError(w, 3 /*Invalid Request*/) return } reportpath := path.Join(baseDir, "reports", reportname+".lua") report_stat, err := os.Stat(reportpath) if err != nil || !report_stat.Mode().IsRegular() { WriteError(w, 3 /*Invalid Request*/) return } report, err := runReport(user, reportpath) if err != nil { WriteError(w, 999 /*Internal Error*/) log.Print(err) return } report.ReportId = reportname err = report.Write(w) if err != nil { WriteError(w, 999 /*Internal Error*/) log.Print(err) return } } }