Merge pull request #1793 from pi-hole/tweak/group_clients_MAC_hostnames

Try to obtain hostname for MAC clients

scripts/pi-hole/php/groups.php

@@ -203,9 +203,45 @@ function JSON_error($message = null)
                 throw new Exception('While executing network table statement: ' . $db->lastErrorMsg());
             }
 
-            // There will always be a result. Unknown host names are NULL
+            // Check if got a hostname from the database. This may not be the case if the client is
+            // specified by MAC address, a hostname or via a more general selector like an interface.
             $name_result = $result->fetchArray(SQLITE3_ASSOC);
-            $res['name'] = $name_result['name'];
+            if(!is_bool($name_result))
+            {
+                $res['name'] = $name_result['name'];
+                error_log("IP: ".$name_result['name']);
+            }
+            else
+            {
+                // Check if we can get a host name from the database when looking up the MAC
+                // address of this client instead.
+                $stmt = $FTLdb->prepare('SELECT name FROM network n JOIN network_addresses na ON na.network_id = n.id WHERE hwaddr=:hwaddr COLLATE NOCASE AND name IS NOT NULL;');
+                if (!$stmt) {
+                    throw new Exception('Error while preparing network table statement: ' . $db->lastErrorMsg());
+                }
+
+                if (!$stmt->bindValue(':hwaddr', $res['ip'], SQLITE3_TEXT)) {
+                    throw new Exception('While binding to network table statement: ' . $db->lastErrorMsg());
+                }
+
+                $result = $stmt->execute();
+                if (!$result) {
+                    throw new Exception('While executing network table statement: ' . $db->lastErrorMsg());
+                }
+
+                // Check if we found a result. There may be multiple entries for
+                // this client in the network_addresses table. We use the first
+                // hostname we find for the sake of simplicity.
+                $name_result = $result->fetchArray(SQLITE3_ASSOC);
+                if(!is_bool($name_result))
+                {
+                    $res['name'] = $name_result['name'];
+                }
+                else
+                {
+                    $res['name'] = null;
+                }
+            }
 
             $groups = array();
             while ($gres = $group_query->fetchArray(SQLITE3_ASSOC)) {