加固房间准入与消息广播边界

app/Events/MessageSent.php

@@ -10,12 +10,17 @@
 
 namespace App\Events;
 
+use App\Models\User;
 use Illuminate\Broadcasting\InteractsWithSockets;
 use Illuminate\Broadcasting\PresenceChannel;
+use Illuminate\Broadcasting\PrivateChannel;
 use Illuminate\Contracts\Broadcasting\ShouldBroadcastNow;
 use Illuminate\Foundation\Events\Dispatchable;
 use Illuminate\Queue\SerializesModels;
 
+/**
+ * 类功能：根据消息可见范围选择广播频道。
+ */
 class MessageSent implements ShouldBroadcastNow
 {
     use Dispatchable, InteractsWithSockets, SerializesModels;
@@ -32,14 +37,25 @@ class MessageSent implements ShouldBroadcastNow
     ) {}
 
     /**
-     * Get the channels the event should broadcast on.
+     * 获取消息应广播到的频道。
      *
-     * 聊天消息广播至包含在线状态管理的 PresenceChannel。
+     * 公共消息走房间 Presence 频道；
+     * 定向消息 / 悄悄话只发给发送方与接收方的私有用户频道。
      *
      * @return array<int, \Illuminate\Broadcasting\Channel>
      */
     public function broadcastOn(): array
     {
+        if ($this->shouldBroadcastPrivately()) {
+            $privateChannels = [];
+
+            foreach ($this->resolveVisibleUserIds() as $userId) {
+                $privateChannels[] = new PrivateChannel('user.'.$userId);
+            }
+
+            return $privateChannels;
+        }
+
         return [
             new PresenceChannel('room.'.$this->roomId),
         ];
@@ -56,4 +72,42 @@ class MessageSent implements ShouldBroadcastNow
             'message' => $this->message,
         ];
     }
+
+    /**
+     * 判断当前消息是否应仅广播给特定用户。
+     */
+    private function shouldBroadcastPrivately(): bool
+    {
+        $toUser = trim((string) ($this->message['to_user'] ?? ''));
+
+        return $toUser !== '' && $toUser !== '大家';
+    }
+
+    /**
+     * 解析本条消息真正可见的用户 ID 列表。
+     *
+     * @return array<int, int>
+     */
+    private function resolveVisibleUserIds(): array
+    {
+        $userIds = [];
+
+        $fromUser = trim((string) ($this->message['from_user'] ?? ''));
+        if ($fromUser !== '') {
+            $senderId = User::query()->where('username', $fromUser)->value('id');
+            if ($senderId !== null) {
+                $userIds[] = (int) $senderId;
+            }
+        }
+
+        $toUser = trim((string) ($this->message['to_user'] ?? ''));
+        if ($toUser !== '' && $toUser !== '大家') {
+            $receiverId = User::query()->where('username', $toUser)->value('id');
+            if ($receiverId !== null) {
+                $userIds[] = (int) $receiverId;
+            }
+        }
+
+        return array_values(array_unique($userIds));
+    }
 }