调整工具类的方法，优化方法调用及增加迁移工具及其用法

examples/middleware_ratelimit_example.go

@@ -0,0 +1,89 @@
+package main
+
+import (
+	"log"
+	"net/http"
+	"time"
+
+	commonhttp "git.toowon.com/jimmy/go-common/http"
+	"git.toowon.com/jimmy/go-common/middleware"
+)
+
+// 示例：限流中间件的使用
+// 展示不同的限流策略
+func main() {
+	// 策略1：按IP限流（10请求/分钟）
+	ipLimitChain := middleware.NewChain(
+		middleware.RateLimitByIP(10, time.Minute),
+	)
+
+	// 策略2：按用户ID限流（100请求/分钟）
+	limiter := middleware.NewTokenBucketLimiter(100, time.Minute)
+	userLimitConfig := &middleware.RateLimitConfig{
+		Limiter: limiter,
+		KeyFunc: func(r *http.Request) string {
+			// 从请求头获取用户ID
+			userID := r.Header.Get("X-User-ID")
+			if userID != "" {
+				return "user:" + userID
+			}
+			// 没有用户ID则使用IP
+			return "ip:" + r.RemoteAddr
+		},
+		OnRateLimitExceeded: func(w http.ResponseWriter, r *http.Request, key string) {
+			log.Printf("Rate limit exceeded for key: %s, path: %s", key, r.URL.Path)
+		},
+	}
+	userLimitChain := middleware.NewChain(
+		middleware.RateLimit(userLimitConfig),
+	)
+
+	// 路由1：按IP限流的API（严格限制）
+	http.Handle("/api/public", ipLimitChain.ThenFunc(func(w http.ResponseWriter, r *http.Request) {
+		h := commonhttp.NewHandler(w, r)
+		h.Success(map[string]interface{}{
+			"message": "Public API - IP rate limited (10/min)",
+			"tip":     "Try refreshing quickly to see rate limiting",
+		})
+	}))
+
+	// 路由2：按用户ID限流的API（宽松限制）
+	http.Handle("/api/private", userLimitChain.ThenFunc(func(w http.ResponseWriter, r *http.Request) {
+		h := commonhttp.NewHandler(w, r)
+		userID := r.Header.Get("X-User-ID")
+		if userID == "" {
+			h.Error(401, "Missing X-User-ID header")
+			return
+		}
+		h.Success(map[string]interface{}{
+			"message": "Private API - User rate limited (100/min)",
+			"user_id": userID,
+		})
+	}))
+
+	// 路由3：无限流的API（用于测试对比）
+	http.HandleFunc("/api/unlimited", func(w http.ResponseWriter, r *http.Request) {
+		h := commonhttp.NewHandler(w, r)
+		h.Success(map[string]interface{}{
+			"message": "Unlimited API - No rate limiting",
+		})
+	})
+
+	// 启动服务器
+	addr := ":8080"
+	log.Printf("Server starting on %s", addr)
+	log.Println("Test endpoints:")
+	log.Printf("  - IP limited (10/min):   http://localhost%s/api/public", addr)
+	log.Printf("  - User limited (100/min): http://localhost%s/api/private (add X-User-ID header)", addr)
+	log.Printf("  - No limit:              http://localhost%s/api/unlimited", addr)
+	log.Println("\nTest with curl:")
+	log.Printf("  curl http://localhost%s/api/public", addr)
+	log.Printf("  curl -H 'X-User-ID: user123' http://localhost%s/api/private", addr)
+	log.Println("\nResponse headers:")
+	log.Println("  X-RateLimit-Limit:     Total allowed requests")
+	log.Println("  X-RateLimit-Remaining: Remaining requests")
+	log.Println("  X-RateLimit-Reset:     Reset timestamp")
+
+	log.Fatal(http.ListenAndServe(addr, nil))
+}
+