package cleanhttp import ( "net/http" "strings" "unicode" ) // HandlerInput provides input options to cleanhttp's handlers type HandlerInput struct { ErrStatus int } // PrintablePathCheckHandler is a middleware that ensures the request path // contains only printable runes. func PrintablePathCheckHandler(next http.Handler, input *HandlerInput) http.Handler { if input == nil { input = &HandlerInput{ ErrStatus: http.StatusBadRequest, } } // Default to http.StatusBadRequest on error if input.ErrStatus == 0 { input.ErrStatus = http.StatusBadRequest } return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) { // Nil-check on input to make it optional // Check URL path for non-printable characters idx := strings.IndexFunc(r.URL.Path, func(c rune) bool { return !unicode.IsPrint(c) }) if idx != -1 { w.WriteHeader(input.ErrStatus) return } next.ServeHTTP(w, r) return }) }