Gin Series of lectures: Saas Systems, Gin+Jwt+ Casbin RestFul Api Backend Battle to the End 5: RateLimit Access Limit

Speed limiting middleware

The previous article introduced how the GIN framework can be combined with middleware. I even made a sketch. Describe unplucked Onions. Add a layer between the HTTP request and the next processing

Why the speed limit

Client access requires speed limiting in many cases. Like seckill, peak hours, malicious access prevention. There is also the need for speed limit purchase access and many other cases. You need speed limits

How the speed limit

Leverage gin middleware. The following code. You can use redis cache, or other alternatives. To limit the frequency of sci-fi requests. Beyond the frequency we set, that’s good. It’s that simple.


// RateLimiterMiddleware requests frequency limiting middleware
func RateLimiterMiddleware(skipper ... SkipperFunc) gin.HandlerFunc {
	cfg := config.GetGlobalConfig().RateLimiter
	if! cfg.Enable {return func(c *gin.Context) {
			c.Next()
		}
	}

	rc := config.GetGlobalConfig().Redis
	ring := redis.NewRing(&redis.RingOptions{
		Addrs: map[string]string{
			"server1": rc.Addr,
		},
		Password: rc.Password,
		DB:       cfg.RedisDB,
	})

	limiter := redis_rate.NewLimiter(ring)
	limiter.Fallback = rate.NewLimiter(rate.Inf, 0)

	return func(c *gin.Context) {
		if (len(skipper) > 0 && skipper[0](c)) || limiter == nil {
			c.Next()
			return
		}

		userID := ginplus.GetUserID(c)
		if userID == "" {
			c.Next()
			return
		}

		limit := cfg.Count
		rate, delay, allowed := limiter.AllowMinute(userID, limit)
		if! allowed { h := c.Writer.Header() h.Set("X-RateLimit-Limit", strconv.FormatInt(limit, 10))
			h.Set("X-RateLimit-Remaining", strconv.FormatInt(limit-rate, 10))
			delaySec := int64(delay / time.Second)
			h.Set("X-RateLimit-Delay", strconv.FormatInt(delaySec, 10))
			ginplus.ResError(c, errors.ErrTooManyRequests)
			return
		}

		c.Next()
	}
}
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Quick question, what else can we add to the middleware?

You have to think about it. What you think and understand is what you really learn.

Gin Series of lectures: Saas Systems, Gin+Jwt+ Casbin RestFul Api Backend Battle to the End 5: RateLimit Access Limit