javascript - nodejs js 队列运行问题

问题描述

问 题

var array = [1,2,3,4];
function check()
{
if(array.length > 0)
var url = array.pop();
load(url);
}}
function load(url)
{
http.get(url, function(res){
check();
)
}}

做了个简单的队列 但现在 执行一个 再执行 一个 我想批量执行100个 再执行 100个 怎么控制呢 请问

解决方案

• TALK IS CHEAP, SHOW ME THE CODE

• Promise version

const array = []
for(let i = 0; i < 109; ++i) array.push(i)
const once = 100
const times = Math.ceil(array.length / once)
const load = async url => ({ url }) // replace here with your load http.get
const init = async () => {
    const results = []
    for(let n = 0; n < times; ++n) {
        const result = await Promise.all(array.slice(n * once, (n + 1) * once).map(url => load(url)))
        results.push(result)
    }
    return results
}
init().then(console.log).catch(console.error)

• async version

var async = require('async')
var array = [];
// prepare data
for(var i = 0; i < 109; ++i) { // 模拟总共109个请求,可以任意更改
    array.push(i)
}
var once = 100;
var times = Math.ceil(array.length / once);

function parallelRequest(urls, cb) {// urls is an array, contains url
    async.parallel(urls.map(url => load(url)), function(err, results) {
        if(err) return cb(err)
        cb(null, results)
    })
}
function load(url) { 
    return function(callback) {
        get(url, function(res) { // replace it using http.get
            //.... focus on error and handle it
            callback(null, url)
        })
    }
 }
var get = function(url, callback) {
    callback(null, {
        url: 'url' + url
    });
};


// request 100 urls in parallel for each request
async.times(times, function(n, next) {
    parallelRequest(array.slice(n * once, (n + 1) * once), function(err, res) {
        next(err, res);
    });
}, function(err, res) {
    // we should now have times=2 array
    console.log(res)
});

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