How to use the HTTP server function in Go language to implement the current limiting function of dynamic routing?

How to use the HTTP server function in the Go language to implement the current limiting function of dynamic routing

Introduction:
In the actual development process, we often need to perform flow control on the API interface of the Web application to Ensure the system is not flooded with malicious requests. The Go language provides a complete set of HTTP server functions. We can use these functions to implement the current limiting function of dynamic routing.

This article will introduce how to use the HTTP server function in the Go language, combined with commonly used current limiting algorithms, to implement the current limiting function of dynamic routing.

1. What is dynamic routing current limiting?
Dynamic routing current limiting refers to setting different request rate upper limits for different routes (URIs). When the number of requests for a certain route exceeds the upper limit, the server will reject the request for this route.

2. Use Http.HandlerFunc to implement dynamic routing and current limiting
The net/http package in the Go language provides the HandleFunc function for routing requests to a specific processing function. We can implement the current limiting function of dynamic routing in the HandleFunc function.

package main

import (
    "fmt"
    "net/http"
    "sync"
    "time"
)

// 路由统计信息
type RouteStats struct {
    Count      int       // 当前请求数
    LastAccess time.Time // 最近一次访问时间
}

// 路由限流器
type RouteLimiter struct {
    stats      map[string]*RouteStats // 路由统计信息
    maxReq     int                    // 最大请求数
    interval   time.Duration          // 统计时间间隔
    expiration time.Duration          // 统计信息过期时间
    lock       sync.Mutex             // 互斥锁
}

// 初始化路由限流器
func NewRouteLimiter(maxReq int, interval, expiration time.Duration) *RouteLimiter {
    return &RouteLimiter{
        stats:      make(map[string]*RouteStats),
        maxReq:     maxReq,
        interval:   interval,
        expiration: expiration,
    }
}

// 中间件，负责限流检查
func (rl *RouteLimiter) LimitHandler(next http.Handler) http.Handler {
    return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
        // 获取路由
        route := r.URL.Path

        rl.lock.Lock()

        // 如果路由不存在，初始化统计信息
        if _, ok := rl.stats[route]; !ok {
            rl.stats[route] = &RouteStats{Count: 0}
        }

        stats := rl.stats[route]
        rl.lock.Unlock()

        // 检查请求数是否超过上限
        if stats.Count >= rl.maxReq {
            w.WriteHeader(http.StatusTooManyRequests)
            return
        }

        // 更新统计信息
        stats.Count++
        stats.LastAccess = time.Now()

        // 定时清理过期的统计信息
        go func() {
            time.Sleep(rl.expiration)
            rl.lock.Lock()
            defer rl.lock.Unlock()

            if time.Since(stats.LastAccess) >= rl.expiration {
                delete(rl.stats, route)
            }
        }()

        // 调用下一个处理程序
        next.ServeHTTP(w, r)
    })
}

// 处理路由
func handleRoute(w http.ResponseWriter, r *http.Request) {
    fmt.Fprint(w, "Hello, World!")
}

func main() {
    // 创建路由限流器
    limiter := NewRouteLimiter(10, time.Minute, time.Hour)

    // 设置路由处理函数
    http.HandleFunc("/", limiter.LimitHandler(http.HandlerFunc(handleRoute)))

    // 启动HTTP服务器
    http.ListenAndServe(":8080", nil)
}

The above code first defines a RouteStats structure, which is used to store routing statistics, including the number of requests and the most recent access time. Then a RouteLimiter structure is defined to store the statistical information of all routes and provide the implementation of the current limiting function.

NewRouteLimiter function is used to initialize a RouteLimiter object. The parameter maxReq represents the maximum number of requests for each route, interval represents the statistical time interval, expiration represents the expiration time of statistical information.

LimitHandlerThe method is a middleware used to check the current limit of each request. It first gets the requested route and then checks whether the number of requests for that route exceeds the upper limit. If the upper limit is exceeded, an HTTP 429 Too Many Requests response is returned; otherwise, statistics are updated and expired statistics are cleared regularly. The

handleRoute function is an example route processing function, which simply returns a "Hello, World!" string.

In the main function, we created a RouteLimiter object and set a current limiting policy of 10 requests/minute. Then use http.HandleFunc to associate the routing and current limiting middleware, and finally start the HTTP server.

3. Conclusion
Using the HTTP server function in the Go language, we can easily implement the current limiting function of dynamic routing. By customizing middleware and flow limiters, we can flexibly control the flow of different routes to ensure the stability and security of the system.

In actual applications, we can customize different current limiting strategies according to business needs, such as customized current limiting processing based on user identity, request method, request parameters, etc.

(over)

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