pool.js

function createPool (port, host, https, credentials) {
  var pool = new events.EventEmitter();
  pool.clients = [];
  
  var getClient = function () {
    for (var i=0;i<pool.clients.length;i+=1) {
      if (!pool.clients[i].busy) {
        return pool.clients[i];
      }
    }
    var client = createClient(port, host, https, credentials);
    clients.push(client);
    return client;
  };
  
  pool.request = function (method, url, headers) {
    if (!headers) header = {};
    if (!headers.connection) headers.connection = 'keep-alive';
    var client = getClient();
    var request = client.request(method, url, headers);
    var errorListener = function (error) {
      pool.emit("error", error);
      request.emit("error", error);
    }
    client.addListener(errorListener);
    request.addListener("response", function (response) {
      response.addListener("end", function () {
        client.removeListener(errorListener);
        client.busy = false;
      })
    })
    client.busy = true;
    return request;
  };
  pool.end = function () {
    pool.clients.forEach(function (c) {c.end()});
  };

}