node-formidable和一个简单的进度条

Question

如果我查看node-formidable文档,我可以阅读:

"Event: 'progress' (bytesReceived, bytesExpected)
Emitted after each incoming chunk of data that has been parsed. 
Can be used to roll your    own progress bar."

我想知道如何实现我自己的进度条我的意思是如何阅读该信息客户端？我很困惑.它是通过在POST开始后启动的轮询GET实现的,还是可以在上传时从POST请求中读取信息？

如果我看看这个:

http.createServer(function(req, res) {
  if (req.url == '/upload' && req.method.toLowerCase() == 'post') {
    // parse a file upload
    var form = new formidable.IncomingForm();
    form.parse(req, function(err, fields, files) {
      res.writeHead(200, {'content-type': 'text/plain'});
      res.write('received upload:\n\n');
      res.end(sys.inspect({fields: fields, files: files}));
    });
    return;
  }

看起来/ upload url正在处理POST请求并返回一些res.write('收到上传:\n \n');

我的问题是谁可以阅读

res.write('received upload:\n\n');

Answer 1

你不需要覆盖onPart钩子!

只需在每个表单progress事件回调调用中通过套接字广播消息,如下所示:

form.on('progress', function(bytesReceived, bytesExpected) {
  var progress = {
    type: 'progress',
    bytesReceived: bytesReceived,
    bytesExpected: bytesExpected
  };

  socket.broadcast(JSON.stringify(progress));
});

比在客户端上侦听套接字消息.

Answer 2

使用socket.io是一个不错的选择

记得覆盖onPart钩子。

incomingForm.onPart = function(part) {
  part.addListener('data', function() {
    // send back to the client the status
  });
}