fix: harden token search with pagination, rate limiting and input validation

- Add configurable per-user token creation limit (max_user_tokens)
- Sanitize search input patterns to prevent expensive queries
- Add per-user search rate limiting (by user ID)
- Add pagination to search endpoint with strict page size cap
- Skip empty search fields instead of matching nothing
- Hide internal errors from API responses
- Fix Interface2String float64 formatting causing config parse failures
- Add float-string fallback in config system for int/uint fields

middleware/rate-limit.go

@@ -115,3 +115,88 @@ func DownloadRateLimit() func(c *gin.Context) {
 func UploadRateLimit() func(c *gin.Context) {
 	return rateLimitFactory(common.UploadRateLimitNum, common.UploadRateLimitDuration, "UP")
 }
+
+// userRateLimitFactory creates a rate limiter keyed by authenticated user ID
+// instead of client IP, making it resistant to proxy rotation attacks.
+// Must be used AFTER authentication middleware (UserAuth).
+func userRateLimitFactory(maxRequestNum int, duration int64, mark string) func(c *gin.Context) {
+	if common.RedisEnabled {
+		return func(c *gin.Context) {
+			userId := c.GetInt("id")
+			if userId == 0 {
+				c.Status(http.StatusUnauthorized)
+				c.Abort()
+				return
+			}
+			key := fmt.Sprintf("rateLimit:%s:user:%d", mark, userId)
+			userRedisRateLimiter(c, maxRequestNum, duration, key)
+		}
+	}
+	// It's safe to call multi times.
+	inMemoryRateLimiter.Init(common.RateLimitKeyExpirationDuration)
+	return func(c *gin.Context) {
+		userId := c.GetInt("id")
+		if userId == 0 {
+			c.Status(http.StatusUnauthorized)
+			c.Abort()
+			return
+		}
+		key := fmt.Sprintf("%s:user:%d", mark, userId)
+		if !inMemoryRateLimiter.Request(key, maxRequestNum, duration) {
+			c.Status(http.StatusTooManyRequests)
+			c.Abort()
+			return
+		}
+	}
+}
+
+// userRedisRateLimiter is like redisRateLimiter but accepts a pre-built key
+// (to support user-ID-based keys).
+func userRedisRateLimiter(c *gin.Context, maxRequestNum int, duration int64, key string) {
+	ctx := context.Background()
+	rdb := common.RDB
+	listLength, err := rdb.LLen(ctx, key).Result()
+	if err != nil {
+		fmt.Println(err.Error())
+		c.Status(http.StatusInternalServerError)
+		c.Abort()
+		return
+	}
+	if listLength < int64(maxRequestNum) {
+		rdb.LPush(ctx, key, time.Now().Format(timeFormat))
+		rdb.Expire(ctx, key, common.RateLimitKeyExpirationDuration)
+	} else {
+		oldTimeStr, _ := rdb.LIndex(ctx, key, -1).Result()
+		oldTime, err := time.Parse(timeFormat, oldTimeStr)
+		if err != nil {
+			fmt.Println(err)
+			c.Status(http.StatusInternalServerError)
+			c.Abort()
+			return
+		}
+		nowTimeStr := time.Now().Format(timeFormat)
+		nowTime, err := time.Parse(timeFormat, nowTimeStr)
+		if err != nil {
+			fmt.Println(err)
+			c.Status(http.StatusInternalServerError)
+			c.Abort()
+			return
+		}
+		if int64(nowTime.Sub(oldTime).Seconds()) < duration {
+			rdb.Expire(ctx, key, common.RateLimitKeyExpirationDuration)
+			c.Status(http.StatusTooManyRequests)
+			c.Abort()
+			return
+		} else {
+			rdb.LPush(ctx, key, time.Now().Format(timeFormat))
+			rdb.LTrim(ctx, key, 0, int64(maxRequestNum-1))
+			rdb.Expire(ctx, key, common.RateLimitKeyExpirationDuration)
+		}
+	}
+}
+
+// SearchRateLimit returns a per-user rate limiter for search endpoints.
+// 10 requests per 60 seconds per user (by user ID, not IP).
+func SearchRateLimit() func(c *gin.Context) {
+	return userRateLimitFactory(common.SearchRateLimitNum, common.SearchRateLimitDuration, "SR")
+}