test.js

var sys   = require('sys'),
    http  = require('http'),
    spawn = require('child_process').spawn

// this is a simple proxy
http.createServer(function(req, res) {

  // and here is the problem: if I try to do any IO before
  // proxying (like making another request or spawning) it
  // freezes the whole thing.
  doRequest(function() { // change to doRequest or doSpawn and watch it happen
    sys.puts('proxying google.com')
    var google    = http.createClient(80, 'google.com');
    var googleReq = google.request('GET', '/', { 'host': 'google.com' });

    googleReq.addListener('response', function (googleRes) {
      res.writeHead(googleRes.statusCode, googleRes.headers)
      googleRes.addListener('data', function(chunk) {
        sys.puts('\trecv ' + chunk.length)
        res.write(chunk, 'binary')
      })
      googleRes.addListener('end', function() {
        res.end()
      })
    })

    req.addListener('data', function(chunk) {
      sys.puts('\tsend ' + chunk.length)
      googleReq.write(chunk, 'binary')
    })
    req.addListener('end', function() {
      googleReq.end()
    })
  })
}).listen(8000)

function doNothing(callback) {
  callback()
}

function doRequest(callback) {
  var node    = http.createClient(80, 'nodejs.org');
  var nodeReq = node.request('GET', '/', { 'host': 'nodejs.org' });

  nodeReq.addListener('response', function (site1Res) {
    sys.puts('got a response from nodejs.org')
    callback()
  })
  nodeReq.end()
}

function doSpawn(callback) {
  var ls = spawn('ls')
  ls.addListener('exit', function(code) {
    sys.puts('ls exited with ' + code)
    callback()
  })
}