fix null parameter in trim

1 files changed, 1 insertions, 1 deletions

diff --git a/lib/appconfig.php b/lib/appconfig.php
index e73b4ee..47b20b6 100644
--- a/lib/appconfig.php
+++ b/lib/appconfig.php
@@ -427,7 +427,7 @@ class AppConfig {
         if (empty($url)) {
             $url = $this->GetSystemValue($this->_documentserver);
         }
-        if ($url !== "/") {
+        if ($url !== null && $url !== "/") {
             $url = rtrim($url, "/");
             if (strlen($url) > 0) {
                 $url = $url . "/";