remove php warning if there is no config yet

public_html/classes/redirect.admin.class.php

@@ -17,6 +17,7 @@ require_once 'redirect.class.php';
  * 2022-02-03  v1.5  ah  add method isEnabled
  * 2022-05-23  v1.6  ah  add http head check+render output; 
  * 2022-05-31  v1.7  ah  optical changes
+ * 2023-08-28  v1.8  ah  remove php warning if there is no config yet
  */
 
 /**
@@ -149,21 +150,23 @@ class redirectadmin extends redirect {
             }
         }
         $aAliases=$this->_getAliases();
-        foreach($aAliases as $sAlias=>$sConfig){
-            if(isset($aReturn[$sAlias])){
-                $aErrors[]="alias.json: A configuration for alias [$sAlias] is useless. There exists a file redirects_{$sAlias}.json (which has priority).";
-            } else {
-                if(!isset($aReturn[$sConfig])){
-                    $aErrors[]="alias.json: [$sAlias] points to a non existing host [$sConfig] - a file redirects_$sConfig.yml does not exist.";
+        if(is_array($aAliases) && count($aAliases)){
+            foreach($aAliases as $sAlias=>$sConfig){
+                if(isset($aReturn[$sAlias])){
+                    $aErrors[]="alias.json: A configuration for alias [$sAlias] is useless. There exists a file redirects_{$sAlias}.json (which has priority).";
                 } else {
-                    $aReturn[$sConfig]['aliases'][]=$sAlias;
-                    $aReturn[$sAlias]=array(
-                        'type'=>'alias',
-                        'target'=>$sConfig,
-                        'ip'=> $this->_getIp($sAlias),
-                    );
-                    if (!$aReturn[$sAlias]['ip']){
-                        $aErrors[]='alias.json: The hostname was not found in DNS: '.$sAlias;
+                    if(!isset($aReturn[$sConfig])){
+                        $aErrors[]="alias.json: [$sAlias] points to a non existing host [$sConfig] - a file redirects_$sConfig.yml does not exist.";
+                    } else {
+                        $aReturn[$sConfig]['aliases'][]=$sAlias;
+                        $aReturn[$sAlias]=array(
+                            'type'=>'alias',
+                            'target'=>$sConfig,
+                            'ip'=> $this->_getIp($sAlias),
+                        );
+                        if (!$aReturn[$sAlias]['ip']){
+                            $aErrors[]='alias.json: The hostname was not found in DNS: '.$sAlias;
+                        }
                     }
                 }
             }