前端防止服务器过载实现限流的常见策略和技术指南

let lastRequestTime = 0;
const REQUEST_INTERVAL = 500; // 请求间隔为500毫秒

function makeRequest(data) {
    const now = new Date().getTime();
    if (now - lastRequestTime > REQUEST_INTERVAL) {
        lastRequestTime = now;
        // 发起实际的网络请求
        console.log('发起请求:', data);
    } else {
        console.log('请求过于频繁，请稍后再试');
    }
}

class LeakyBucket {
    constructor(rate, capacity) {
        this.rate = rate; // 处理速度（每毫秒处理多少个请求）
        this.capacity = capacity; // 桶的最大容量
        this.waterAmount = 0; // 当前水量
        this.lastLeakTimestamp = Date.now(); // 上次漏水的时间戳
    }

    canMakeRequest() {
        const now = Date.now();
        const elapsedTime = now - this.lastLeakTimestamp;
        const leakedAmount = elapsedTime * this.rate;

        // 更新当前水量
        this.waterAmount = Math.max(0, this.waterAmount - leakedAmount);
        this.lastLeakTimestamp = now;

        if (this.waterAmount < this.capacity) {
            this.waterAmount += 1;
            return true;
        } else {
            return false;
        }
    }
}

const bucket = new LeakyBucket(0.1, 10); // 设置每毫秒处理0.1个请求，最大容量为10

function makeRequest(data) {
    if (bucket.canMakeRequest()) {
        // 发起实际的网络请求
        console.log('发起请求:', data);
    } else {
        console.log('请求过于频繁，请稍后再试');
    }
}

let requestCount = 0;
const MAX_REQUESTS = 5; // 最大请求数
const TIME_WINDOW = 1000; // 时间窗口大小为1秒

function resetCounter() {
    setTimeout(() => {
        requestCount = 0;
    }, TIME_WINDOW);
}

function makeRequest(data) {
    if (requestCount < MAX_REQUESTS) {
        requestCount++;
        // 发起实际的网络请求
        console.log('发起请求:', data);
        if (requestCount === 1) { // 第一次请求时重置计数器
            resetCounter();
        }
    } else {
        console.log('请求过于频繁，请稍后再试');
    }
}

npm install bottleneck

const Bottleneck = require("bottleneck");

// 创建一个限流器，每秒最多允许5个请求
const limiter = new Bottleneck({
    maxConcurrent: 1,
    minTime: 200 // 每200ms允许一个新的请求
});

async function makeRequest(data) {
    await limiter.schedule(() => {
        // 发起实际的网络请求
        console.log('发起请求:', data);
    });
}