go - golang.org/x/time/rate api 请求的速率限制

Question

我已经在 1 天内为 api 登录创建了限制 50 个请求的函数

无功限制 = 50

package middleware

import (
    "log"
    "net"
    "net/http"
    "sync"
    "time"

    "golang.org/x/time/rate"
)

// Create a custom request struct which holds the rate limiter for each
// visitor and the last time that the request was seen.
type request struct {
    limiter  *rate.Limiter
    lastSeen time.Time
}

// Change the the map to hold values of the type request.
// defaultTime using 3 minutes
var requests = make(map[string]*request)
var mu sync.Mutex

func getRequest(ip string, limit int) *rate.Limiter {
    mu.Lock()
    defer mu.Unlock()

    v, exists := requests[ip]
    if !exists {
        limiter := rate.NewLimiter(1, limit)
        requests[ip] = &request{limiter, time.Now()}
        return limiter
    }
    // Update the last seen time for the visitor.
    v.lastSeen = time.Now()
    return v.limiter
}

func throttle(next http.Handler, limit int) http.Handler {
    return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
        ip, _, err := net.SplitHostPort(r.RemoteAddr)
        if err != nil {
            log.Println(err.Error())
            http.Error(w, "Internal Server Error", http.StatusInternalServerError)
            return
        }
        limiter := getRequest(ip, limit)
        fmt.Println(limiter.Allow())
        if limiter.Allow() == false {
            http.Error(w, http.StatusText(http.StatusTooManyRequests), http.StatusTooManyRequests)
            return
        }
        next.ServeHTTP(w, r)
    })
}

这是正确的 ？

因为我试了一下还是通过，功能限制不起作用

我怀疑 NewLimiter()

 limiter := rate.NewLimiter(1, limit)

这意味着 1 个用户只能请求登录 50 个请求/天？ (我已经读过 doc 但我不明白)

Answer 1

来自 rate docs :

func NewLimiter(r Limit, b int) *Limiter

NewLimiter returns a new Limiter that allows events up to rate r and permits bursts of at most b tokens.

所以第一个参数是速率限制，而不是第二个。 Burst 是您希望允许的比速率限制更快的请求数量 - 通常使用值 1为了禁止爆发，任何更高的请求都会在常规速率限制开始之前允许这个数量的请求。无论如何......

创建 rate.Limit根据您的需要，您可以使用辅助函数 rate.Every() :

rt := rate.Every(24*time.Hour / 50)

limiter := rate.NewLimiter(rt, 1)