Moving from blocking functional programming, to non-blocking Node.js programming.

right-way.js

var sys = require('sys');
var http = require('http');
var EventEmitter = require('events').EventEmitter;

TropoSession = function() {
	this.responseBody;	
};

TropoSession.prototype = new EventEmitter;

TropoSession.prototype.makeApiCall =  function(token, parameters) {
	
	var self = this;
	
	var tropoSessionAPI = 'api.tropo.com';
	var path = '/1.0/sessions?action=create&token=' + token;
	
	for(item in parameters) {
		path += '&' + item + '=' + encodeURI(parameters[item]);
	}
	
	var tropo = http.createClient(80, tropoSessionAPI);
	var request = tropo.request('GET', path, {'host': tropoSessionAPI});

	request.end();

	request.on('response', function (response) {
	  response.setEncoding('utf8');
	  self.emit('responseCode', response.statusCode);
	  response.addListener('data', function (chunk) {
		  this.responseBody =  chunk;
	  });
	  response.addListener('end', function() {
		  self.emit('responseBody', this.responseBody);
	  });
	});
	         
};

var token = 'your-token-goes-here';
var parameters = { 'numberToCall': '5551234567', 'messageToSay': 'Hello from Node.' };

// Create a new TropoSession object
var tropo = new TropoSession();

// Make the API call. 
tropo.makeApiCall(token, parameters);

// Add listeners for events emitted from makeApiCall() method.
tropo.addListener('responseCode', function(code){
	sys.puts('Response code: ' + code);
});

tropo.addListener('responseBody', function(body) {
	sys.puts('Response body: ' + body);
});

wrong-way.js

var sys = require('sys');
var http = require('http');

TropoSession = function() {	
	this.responseCode;
	this.responseBody;	
};

TropoSession.prototype.makeApiCall =  function(token, parameters) {
	
	var tropoSessionAPI = 'api.tropo.com';
	var path = '/1.0/sessions?action=create&token=' + token;
	
	for(item in parameters) {
		path += '&' + item + '=' + encodeURI(parameters[item]);
	}
	
	var tropo = http.createClient(80, tropoSessionAPI);
	var request = tropo.request('GET', path, {'host': tropoSessionAPI});

	request.end();

	request.on('response', function (response) {
	  response.setEncoding('utf8');
	  this.responseCode = response.statusCode;
	  response.addListener('data', function (chunk) {
		  this.responseBody =  chunk;
	  });
	});
	         
};

var token = 'your-token-goes-here';
var parameters = { 'numberToCall': '5551234567', 'messageToSay': 'Hello from Node.' };

// Create a new TropoSession object.
var tropo = new TropoSession();

// Make the API call. 
tropo.makeApiCall(token, parameters);

// Display the response from the API call.
sys.puts('Response code: ' + tropo.responseCode);
sys.puts('Response body: ' + tropo.responseBody);