CODEWITHSUNDEEP
javascriptnode.jshttpasynchronouscoffeescript
user3797089
user3797089

Reputation: 25

Asynchronous processing of HTTP requests in node

I have a node.js project, which has a async::queue, which is filled by App::add().

This is the code I use to create the server:

app = new App config
server = http.createServer (req, res) ->
  app.add req, res, (err) ->
    res.headers = 'Content-Type': 'application/json'
    res.end JSON.stringify error: err
.listen config.port

App::add() takes the paramters from req and adds a task to the queue with the callback. The queue is processed with a function which ends end. If an error occures, it will be given out to the user.

Works fine, so far. But when do multiple requests in parallel, only one request at the time is processed.

I tried:

How do I handle concurrent requests?

Thanks in advance.

Edit:

To clear some things up, this is what I want:

  1. Many many clients request the service to download a zip
  2. They line up in a queue, n are processed at a time
  3. Everyone get's their zip, as soon as it's finished

Edit 2:

I tried to use the cluster module, but this doesn't help much, because I have to end the res anyways.

Edit 3:

I tried to return a stream without closing, but no success either. I'm a bit desperate, maybe I'll just forward people to another server where they can download their file.

Upvotes: 2

Views: 247

Answers (1)

Dmitry
Dmitry

Reputation: 289

NodeJS, like javascript in your browser, is single threaded. That means it can process only one continuous block of code at a time. In your example (since you haven't supplied a code for your queue processing, I assume that passed function is the actual processing code). Since it don't have any I/O (that means it don't block on waiting for something from external source like file system or database), the function's logic must fully complete before nodejs can start processing another event.

If you need more details, here's the first link I've googled about how nodejs works in concurrent environment: http://blog.mixu.net/2011/02/01/understanding-the-node-js-event-loop/

Upvotes: 1

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