如何设置上传的文件名？

By using 'multer' , I made it to request image file like this.

这个文件存储在我设置的“上传”文件夹中。 我的代码如下：

var multer  = require('multer')
var upload = multer({dest:'./uploads/'});
//var upload = multer({ storage: storage });
var app = express();
app.use(app.router);
app.post('/upload', upload.single('puzzle'), function (req, res, next) {
    console.log(req.file);
});

但我想将文件名设置为“abc.png”而不是“abc”

我阅读了文档，发现

var storage = multer.diskStorage({
  destination: function (req, file, cb) {
    cb(null, '/uploads');
  },
  filename: function (req, file, cb) {
    cb(null, file.fieldname + '-' + Date.now());
  }
});

var upload = multer({ storage: storage });

所以我修改后的代码如下：

var multer  = require('multer')
var storage = multer.diskStorage({
  destination: function (req, file, cb) {
    cb(null, '/uploads');
  },
  filename: function (req, file, cb) {
    cb(file.filename+'.png', file);
  }
});

var upload = multer({ storage: storage });
var app = express();
app.use(app.router);
app.post('/upload', upload.single('puzzle'), function (req, res, next) {
    console.log(req.file);
});

但在这种情况下，出现错误并显示 'Error: ENOENT, open '/uploads/puzzle-1449496743377' ，不像上面的图片......

我该如何解决这个问题？

我确信许多像我这样的新手开发人员会因为不友善的文档而遇到麻烦......

    var fs = require('fs');
var multer  = require('multer')
//var uploader = multer({dest:'./uploads/'});

var storage = multer.diskStorage({
  destination: function (req, file, cb) {
    cb(null, './uploads/')
  },
  filename: function (req, file, cb) {
    crypto.pseudoRandomBytes(16, function (err, raw) {
      cb(null, raw.toString('hex') + Date.now() + '.png');
    });
  }
});
var upload = multer({ storage: storage });
var app = express();
app.use(app.router);
app.post('/upload', upload.single('puzzle'), function (req, res, next) {
    console.log(req.file);
});

已解决，谢谢大家，谢谢