diff --git a/src/OneBot/Driver/Event/WebSocket/WebSocketOpenEvent.php b/src/OneBot/Driver/Event/WebSocket/WebSocketOpenEvent.php
index 9e55de1..4466b5a 100644
--- a/src/OneBot/Driver/Event/WebSocket/WebSocketOpenEvent.php
+++ b/src/OneBot/Driver/Event/WebSocket/WebSocketOpenEvent.php
@@ -12,7 +12,7 @@ class WebSocketOpenEvent extends DriverEvent
 {
     protected ServerRequestInterface $request;
 
-    protected ?ResponseInterface $response;
+    protected ?ResponseInterface $response = null;
 
     protected int $fd;
 
diff --git a/src/OneBot/V12/Object/OneBotEvent.php b/src/OneBot/V12/Object/OneBotEvent.php
index 488bdd3..4437a27 100644
--- a/src/OneBot/V12/Object/OneBotEvent.php
+++ b/src/OneBot/V12/Object/OneBotEvent.php
@@ -68,6 +68,9 @@ public function __call(string $name, array $args = [])
             return null;
         }
         if (str_starts_with($name, 'set')) {
+            if ($name === 'setMessage') {
+                $this->message_segment_cache = null;
+            }
             $key = Utils::camelToSeparator(substr($name, 3));
             if (isset($this->data[$key])) {
                 $this->data[$key] = $args[0];
@@ -132,6 +135,26 @@ public function getMessage(bool $return_assoc_array = false): ?array
         return $this->message_segment_cache;
     }
 
+    /**
+     * 获取纯文本消息
+     */
+    public function getMessageString(): string
+    {
+        $message = $this->getMessage();
+        if ($message === null) {
+            return '';
+        }
+        $message_string = '';
+        foreach ($message as $segment) {
+            if ($segment->type === 'text') {
+                $message_string .= $segment->data['text'];
+            } else {
+                $message_string .= '[富文本:' . $segment->type . ']';
+            }
+        }
+        return $message_string;
+    }
+
     public function jsonSerialize(): array
     {
         return $this->data;