nodejs 下载远程图片

var express = require('express');var request = require('request');var http = require('http');var url = require('url');var fs = require("fs");var router = express.Router();/* GET home page. */router.get('/', function (req, res, next) {    var url = "http://www.valu.cn/images/1.gif";    //request('http://www.valu.cn/images/1.gif').pipe(fs.createWriteStream('./public/upload/downImg/logonew.png'));    var req = http.get(url, function (res) {        var imgData = "";        res.setEncoding("binary"); //必定要设置response的编码为binary不然会下载下来的图片打不开        res.on("data", function (chunk) {            imgData += chunk;        });        res.on("end", function () {            fs.writeFile("./public/upload/downImg/logonew.png", imgData, "binary", function (err) {                if (err) {                    console.log("保存失败");                }                console.log("保存成功");            });        });        res.on("error", function (err) {            console.log("请求失败");        });    });    req.on('error', function (err) {        console.log("请求失败2" + err.message);    });    res.render('index', {title: '首页2'});});module.exports = router;