add utils.go

utils.go

@@ -0,0 +1,33 @@
+package main
+
+import (
+	"fmt"
+	"net/http"
+	"os"
+	"strconv"
+	"strings"
+)
+
+func formatSize(file os.FileInfo) string {
+	if file.IsDir() {
+		return "-"
+	}
+	size := file.Size()
+	switch {
+	case size > 1024*1024:
+		return fmt.Sprintf("%.1fM", float64(size)/1024/1024)
+	case size > 1024:
+		return fmt.Sprintf("%.1fK", float64(size)/1024)
+	default:
+		return strconv.Itoa(int(size))
+	}
+	return ""
+}
+
+func getRealIP(req *http.Request) string {
+	xip := req.Header.Get("X-Real-IP")
+	if xip == "" {
+		xip = strings.Split(req.RemoteAddr, ":")[0]
+	}
+	return xip
+}