add function to list all files in a given directory

goutil.go

@@ -3,6 +3,7 @@ package goutil
 import (
 	"io/ioutil"
 	"path/filepath"
+	"strings"
 )
 
 func WriteFile(filename string, data string) error {
@@ -18,3 +19,19 @@ func TrimExt(path string) string {
 	extension := filepath.Ext(path)
 	return path[0 : len(path)-len(extension)]
 }
+
+func ListFilesExt(dir string, ext string) []string {
+	list := make([]string, 0)
+	ext = strings.ToUpper(ext)
+	files, err := ioutil.ReadDir(dir)
+	if err == nil {
+		for _, file := range files {
+			if !file.IsDir() {
+				if strings.ToUpper(filepath.Ext(file.Name())) == ext {
+					list = append(list, file.Name())
+				}
+			}
+		}
+	}
+	return list
+}