初始提交：姜十三论坛 Jiang13 Forum

轻量自用论坛，Go 单二进制 + React SPA 内嵌 + SQLite。

Co-authored-by: Cursor <cursoragent@cursor.com>

service/ratelimit.go

@@ -0,0 +1,69 @@
+package service
+
+import (
+	"sync"
+	"time"
+)
+
+// RateLimiter 简单内存限流器，防止重复刷屏
+type RateLimiter struct {
+	mu       sync.Mutex
+	records  map[string][]time.Time
+	limit    int           // 窗口内最大次数
+	window   time.Duration // 时间窗口
+}
+
+func NewRateLimiter(limit int, window time.Duration) *RateLimiter {
+	r := &RateLimiter{
+		records: make(map[string][]time.Time),
+		limit:   limit,
+		window:  window,
+	}
+	go r.cleanup()
+	return r
+}
+
+// Allow 检查 key（如 userID+action）是否允许操作
+func (r *RateLimiter) Allow(key string) bool {
+	r.mu.Lock()
+	defer r.mu.Unlock()
+	now := time.Now()
+	cutoff := now.Add(-r.window)
+	times := r.records[key]
+	var valid []time.Time
+	for _, t := range times {
+		if t.After(cutoff) {
+			valid = append(valid, t)
+		}
+	}
+	if len(valid) >= r.limit {
+		r.records[key] = valid
+		return false
+	}
+	valid = append(valid, now)
+	r.records[key] = valid
+	return true
+}
+
+func (r *RateLimiter) cleanup() {
+	ticker := time.NewTicker(5 * time.Minute)
+	for range ticker.C {
+		r.mu.Lock()
+		now := time.Now()
+		cutoff := now.Add(-r.window * 2)
+		for k, times := range r.records {
+			var valid []time.Time
+			for _, t := range times {
+				if t.After(cutoff) {
+					valid = append(valid, t)
+				}
+			}
+			if len(valid) == 0 {
+				delete(r.records, k)
+			} else {
+				r.records[k] = valid
+			}
+		}
+		r.mu.Unlock()
+	}
+}