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"); //一定要设置response的编码为binary否则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;