javascript - Node 文件传输在图像目录中上传 x 字节的图像，但已损坏

Question

我正在使用 Node 的 Busboy 模块来解析文件。首先上传一个文件 -> 将上传的文件推送到 images 目录。我不知道为什么，但代码正在传输字节，即它确实创建了具有正确字节的图像，但当单击文件时，它已损坏。这是我的代码:

var busboy = new Busboy({ headers: req.headers });
    busboy.on('file', function(fieldname, file, filename, encoding, mimetype) {
      console.log('File [' + fieldname + ']: filename: ' + filename + ', encoding: ' + encoding + ', mimetype: ' + mimetype);

      file.on('data', function(data) {
        var fstream = fs.createWriteStream('./images/' + filename); 
        file.pipe(fstream);
        fstream.on('close', function () {
            console.log("Upload Finished of " + filename);

        });
        console.log('File [' + fieldname + '] got ' + data.length + ' bytes');
      });
      file.on('end', function() {
        console.log('File [' + fieldname + '] Finished');
      });
    });

Answer 1

data 事件可以被发出多次次。这里的解决方案很简单:只需将 file 通过管道传输到可写流一次即可。例如:

var crypto = require('crypto');
var path = require('path');

// ...

var busboy = new Busboy({ headers: req.headers });
busboy.on('file', function(fieldname, file, filename, encoding, mimetype) {
  // You will want to somehow sanitize `filename` if you are going to use
  // it when use it as part of the filename on disk, as it could be maliciously
  // constructed to overwrite to other parts of your filesystem.
  //
  // The solution I use here is to simply hash the filename, but you could
  // use `path.resolve('./images/', filename)` instead and check that the
  // result starts with `__dirname + '/images/'`.
  var ext = path.extname(filename);
  filename = crypto.createHash('sha1')
                   .update(filename, 'utf8')
                   .digest('hex') + ext;

  var diskStream = fs.createWriteStream('./images/' + filename);
  file.pipe(diskStream).on('finish', function() {
    console.log('Finished writing file');
  });
});