Node.js https.request client's req.end() never called when the file size is 0

I'm trying to create node server for the use of proxy for file upload.

The main role of this server is get the HTTP PUT request from client end proxy it to OpenStack Swift server.

Source code looks like follow:

var https = require('https')
   // ... some modules are required
   , Swift = reuiqre('swift')
   , mysql = require('mysql');

// some configurations

function request(options, callback, pipe){
  var client = https.request(options, function(res){
    res.on('end', function(err){
      // something to do
    });
  });

  pipe.req.on('data', function(chunk){
    client.write(buffer);
  });

  pipe.req.on('end', function(err){
    client.end();
    callback(null, res);
  });
}

app.put('/upload', function(req, res, next){
  var swift = new Swift(swiftConfig, function(err, result) {
    var options = some logics for options here;
    db.query('SELECT * FROM SOMETABLE WHERE SOMETHING = ?'
          , [something]
          , function (err, results) {
              if (err) return next(err);
              request.call(swift, options, function(err, result) {
                if(err) { res.send(500, err) };
                res.end();
              }, {req: req});
    });
  });
}

The code above works well when I PUT a file from my client PC.

However, the problem is occurred when I upload(ie., HTTP PUT) a file whose content-length is zero(0).

Even if the size of file to upload is 1KB, then it works fine.

But when I'm trying to upload 0 byte file(empty http body), the 'end' event(the code below) of has never been called and finally the request emit error of "Error: socket hang up".

  pipe.req.on('end', function(err){
    client.end();
    callback(null, res);
  });

Can anyone help me?