Question

我在计算密集型函数运行时轮询我的node / express应用程序。现在这个函数阻止node / express以某种方式立即回复到http-get请求;相反，这些轮询器请求排队并在计算完成后返回所有请求。

是否有一个模块或技术允许节点“呼吸”＃34;并回复http请求？

在我的主要路线内

module.exports.parse = (req, res) ->

 # Synchronously Cascading Waterfalls

  async.waterfall [
    (next) ->
      MyOtherOtherModel.findById req.params.id, (err, data) ->
        if err
          next err
        if !data._id
          dataError = new Error "Fatal error: Data Result is empty!"
          next dataError
        next null, data

    (data, next) ->
      fs.readdir 'uploads', (err, files) ->
        if err
          next err
        next null, data, files

    (data, files, next) ->

      async.each files, ((file, callback) ->
        # Do intensive stuff here, parsing, I/O, mapping, etc

        async.waterfall [
          (innerNext) ->
            MyOtherModel.findByIdAndUpdate data._id,
              { # data
                $push:
                  'uploadedFiles':
                    fileName: file
                    length: data.length
              },
              { # options
                safe: true
                upsert: true
                new: true
              }, (err, dataObjects) ->
                if err
                  innerNext err
                innerNext null, dataObjects
          (dataObjects, innerNext) ->
            async.each items, ((item, innerCallback) ->
              MyModel.create myData, (err, result) ->
                if err
                  innerCallback err
                innerCallback null
            ), (err) ->
              if err
                innerNext err
              innerNext null
        ], (err) ->
          if err
            callback err
          callback null
      ), (err) ->
        if err
          next err
        # Leave node room to breath, but it isnt working
        setTimeout (->
          next null
        ), 1000
    ], (err) ->
      if err
        throw Error err # All Errors bubble up to this point

  # We return immediately, so that express is free to handle poller requests

  res.status(202).send
    status: 'OK'
    error: 'Started Computation.'
  return

我的投手

module.exports.poll = (req, res) ->

  # Ask DB and calculate finishedPercentage

  res.status(206).send
    status     : 'Partial Content'
    type       : 'info'
    error      : percentageFinished + ' % geparsed.'
    progress     : percentageFinished

控制台输出

Parsing..
nextFile..
nextFile..
nextFile..
nextFile..
Progress: 100.0 %
Progress: 100.0 %
...

因此，您可以看到轮询器以某种方式排队，直到Node认为它有时间回答http请求。我希望这一进展能够不断更新。

Answer 1

一种解决方案是将CPU密集型任务委派给child process，该built-in message passing mechanism偶尔会通过节点{{3}}或仅通过写入stdout并让父进程中继该信息来报告进度更新回到客户端。

Node Express Poller被计算密集型路由阻塞

1 个答案: