diff --git a/CWeChatRobot/utils.h b/CWeChatRobot/utils.h
new file mode 100644
index 0000000000000000000000000000000000000000..b234c37d36a51f89dab62eaec9afb87955bd9a11
--- /dev/null
+++ b/CWeChatRobot/utils.h
@@ -0,0 +1,52 @@
+#pragma once
+#include <set>
+#include <utility>
+#include <chrono>
+
+#define CHRONO std::chrono
+typedef unsigned long long ull;
+
+/*
+ * 一个简单的带过期时间检查和清理的集合，interval为毫秒
+ * ExpireSet es(1000); // 过期时间1秒
+ * es.CheckIfDuplicatedAndAdd(1); true, 未重复
+ * es.CheckIfDuplicatedAndAdd(1); false, 重复
+ * After 1s;
+ * es.CheckIfDuplicatedAndAdd(2); 添加<2>并清理过期的元素<1>
+ */
+class ExpireSet
+{
+public:
+    ull interval; // 毫秒
+    ExpireSet(ull interval)
+    {
+        this->interval = interval;
+    }
+    bool CheckIfDuplicatedAndAdd(ull id)
+    {
+        bool ok = true;
+        if (ids.count(id) != 0)
+        {
+            ok = false;
+        }
+        Add(id);
+        return ok;
+    }
+
+private:
+    std::set<ull> ids;
+    std::pair<ull, ull> p;
+
+    void Add(ull id)
+    {
+        // 毫秒
+        auto now = CHRONO::time_point_cast<CHRONO::milliseconds>(CHRONO::system_clock::now());
+        if (p.second < now.time_since_epoch().count())
+        {
+            ids.clear();
+            p.first = now.time_since_epoch().count();
+            p.second = p.first + interval;
+        }
+        ids.insert(id);
+    }
+};