直接上乾貨

var    http = require('http');
var    path = require('path');
var mkdirp = require('mkdirp');
var request = require('request');
var fs = require('fs');

var download = function(uri, dir,filename){
    request.head(uri, function(err, res, body){
        request(uri).pipe(fs.createWriteStream(dir + "/" + filename));
    });
};
app.all('/test/download', function(req, res){
    var basePath=path.dirname(__filename);
    var targetPath = basePath+ "/public";
    var filePath2 = 'http://cdn.yyupload.com/down/673731/tpsc/mktmtp_PNG/122.hudie/54.png';
    download(filePath2,targetPath,"abc.jpg");
    res.end("下載成功");
});