node.js - nodejs expressjs result.end() 如果从回调中调用，则不发送 POST 请求的结果

Question

我有一个快速应用程序可以处理如下所示的发布请求（coffeescript）

#Handle CSV Uploads
app.post '/upload', (req, res) ->
  res.setHeader 'Content-Type', 'text/json'

  if !req.session.user?
    res.json
      success: false
    return

  if !req.files.files? || !req.files.files.length
    res.json
      success: false
      message: 'No Files Uploaded'
    return

  file = req.files.files[0]

  if file.mime is not 'text/csv'
    res.json
      success: false
      message: 'Invalid Upload Type'
    return


  #Find IDs of all shippers referenced in this csv
  client_shippers_ids = []
  chainer = new Sequelize.Utils.QueryChainer

  csv()
    .from.stream(fs.createReadStream(file.path))
    .to.path('/tmp/tempcsv.out')
    .transform((row) ->

      return row

    ).on('record', (row, index)->

      chainer.add DB.Order.create
        po_num:      Math.random() + ''
        description: Math.random() + ''
        requested_by: ''
        received:    false
        status:      'Purchase Order Received'

    ).on('end', (count)->
      console.log 'end'
      console.log count
      chainer.run().success () ->
        console.log 'chainer fin'
        res.json #<----- This part does not send
          success: true
          message: 'complete'
    )

特别是这个电话

res.json #<----- This part does not send
              success: true
              message: 'complete'

不返回任何东西。在此之前是否调用了 res.end() ？