aadd first files based on caddy-filemanager

Former-commit-id: 20baeeb41a9555cefc3b31b495e24e907736c443

utils/errors.go

@@ -0,0 +1,24 @@
+package utils
+
+import (
+	"net/http"
+	"os"
+)
+
+// ErrorToHTTPCode converts errors to HTTP Status Code.
+func ErrorToHTTPCode(err error, gone bool) int {
+	switch {
+	case os.IsPermission(err):
+		return http.StatusForbidden
+	case os.IsNotExist(err):
+		if !gone {
+			return http.StatusNotFound
+		}
+
+		return http.StatusGone
+	case os.IsExist(err):
+		return http.StatusGone
+	default:
+		return http.StatusInternalServerError
+	}
+}