Added option to force refreshInterval from command line, and added minimum interval of 500ms

README.md

@@ -62,6 +62,8 @@ If a positive-value `refresh=<integer><unit>` query parameter is provided, the p
 
 This can be used to generate a sort of slideshow of files.
 
+Minimum accepted value is 500ms, as anything lower seems to cause inconsistent behavior. This might be changed in a future release.
+
 Supported units are `ns`, `us`/`µs`, `ms`, `s`, `m`, and `h`.
 
 ## Caching
@@ -105,6 +107,7 @@ Flags:
       --minimum-files uint32      skip directories with file counts under this value
   -p, --port uint16               port to listen on (default 8080)
   -r, --recursive                 recurse into subdirectories
+      --refresh-interval string   force refresh interval equal to this duration (minimum 500ms)
   -s, --sort                      enable sorting
       --stats                     expose stats endpoint
       --stats-file string         path to optional persistent stats file

cmd/root.go

@@ -5,13 +5,19 @@ Copyright © 2023 Seednode <seednode@seedno.de>
 package cmd
 
 import (
+	"errors"
 	"log"
+	"time"
 
 	"github.com/spf13/cobra"
 )
 
+var (
+	ErrIncorrectRefreshInterval = errors.New("refresh interval must be a duration string >= 500ms")
+)
+
 const (
-	Version string = "0.57.1"
+	Version string = "0.57.2"
 )
 
 var (
@@ -24,6 +30,7 @@ var (
 	minimumFileCount uint32
 	port             uint16
 	recursive        bool
+	refreshInterval  string
 	sorting          bool
 	statistics       bool
 	statisticsFile   string
@@ -38,6 +45,13 @@ var (
 			if debug {
 				cmd.MarkFlagRequired("cache")
 			}
+
+			if refreshInterval != "" {
+				interval, err := time.ParseDuration(refreshInterval)
+				if err != nil || interval < 500*time.Millisecond {
+					log.Fatal(ErrIncorrectRefreshInterval)
+				}
+			}
 		},
 		RunE: func(cmd *cobra.Command, args []string) error {
 			err := ServePage(args)
@@ -67,6 +81,7 @@ func init() {
 	rootCmd.Flags().Uint32Var(&minimumFileCount, "minimum-files", 0, "skip directories with file counts under this value")
 	rootCmd.Flags().Uint16VarP(&port, "port", "p", 8080, "port to listen on")
 	rootCmd.Flags().BoolVarP(&recursive, "recursive", "r", false, "recurse into subdirectories")
+	rootCmd.Flags().StringVar(&refreshInterval, "refresh-interval", "", "force refresh interval equal to this duration (minimum 500ms)")
 	rootCmd.Flags().BoolVarP(&sorting, "sort", "s", false, "enable sorting")
 	rootCmd.Flags().BoolVar(&statistics, "stats", false, "expose stats endpoint")
 	rootCmd.Flags().StringVar(&statisticsFile, "stats-file", "", "path to optional persistent stats file")

cmd/web.go

@@ -408,18 +408,24 @@ func serverErrorHandler() func(http.ResponseWriter, *http.Request, interface{})
 }
 
 func RefreshInterval(r *http.Request, Regexes *Regexes) (int64, string) {
-	refreshInterval := r.URL.Query().Get("refresh")
+	var interval string
 
-	if !Regexes.units.MatchString(refreshInterval) {
+	if refreshInterval == "" {
-		return 0, "0ms"
+		interval = r.URL.Query().Get("refresh")
+	} else {
+		interval = refreshInterval
 	}
 
-	duration, err := time.ParseDuration(refreshInterval)
+	duration, err := time.ParseDuration(interval)
-	if err != nil {
-		return 0, "0ms"
-	}
 
-	return duration.Milliseconds(), refreshInterval
+	switch {
+	case err != nil || duration == 0:
+		return 0, "0ms"
+	case duration < 500*time.Millisecond:
+		return 500, "500ms"
+	default:
+		return duration.Milliseconds(), interval
+	}
 }
 
 func SortOrder(r *http.Request) string {