Node.js platform, let’s create scalable network applications

Node is an innovative new platform available that allows you to quickly and easily build fast, scalable network applications, with just a few clicks of the mouse. Node.js has been built on Chrome’s JavaScript runtime environment, allowing you this opportunity to build scalable network applications quickly and easily. Node.js is an event driven, non-blocking I/O model that provides lightweight and efficient services, which are ideal for data intensive and real-time applications that run across a variety of devices. Using Node allows you to handle a variety of your client’s connections, concurrently. Node tells your operating system, either through kqueue, select, epoll or /dev/poll that these systems need to be notified when a new connection has been made, and then it promptly goes to sleep. If there is another, new connection made, it will execute your callback, and every connection has a minimal allocation.

As an example, the “hello world” server on node.js would be as follows:

var http = require('http');
http.createServer(function (req, res) {
     res.writeHead(200, {'Content-Type': 'text/plain'});
     res.end('Hello World\n');
}).listen(1337, "127.0.0.1");
console.log('Server running at http://127.0.0.1:1337/');

Although this is contrasting to the more common concurrency model available today where OS threads are more commonly used, this thread-based networking is extremely inefficient and incredibly hard to use. Node proffers a much higher memory efficiency under extremely high load systems, than those that allocate only two mb thread stacks for every connection available. In addition, Node users also do not have to worry about deadlocking in the process, because there are no locks. Virtually zero functions in Node directly perform I/O, allowing the process to avoid blockage. Because there are no blocks, anyone that is less than expert in programming can develop a fast system using node.js, versus other platforms.

Node is extremely similar in its design and influence, such as systems like Event Machine and Twisted. However, knowing that takes this event model just a little bit further, presenting an event loop as a language construct, instead of as a whole library. In differing systems, there is always a blocking call that starts the event loop. Generally, one defines the behavior of the system through these callbacks at the beginning of the script, and then at the end it starts a server through call blocking, an example of which being EventMachine::run(). In Node this started the event loop call does not exist. It simply enters into the event loop following execution of the input script. Noted then exit’s the event loop within there are no more callbacks available to perform, and this behavior is very similar to a browser JavaScript; the event loop is hidden.

In Node, HT key PE is priority protocol, because Node’s HTTP library far surpasses the author’s experience, by working in developing Web servers. As an example of this, streaming data through most web frameworks is absolutely impossible. However, Node attempts to correct these issues in its own HTTP parser and API combining these with Node’s sole invented infrastructure; it provides a solid foundation for Web libraries or frameworks. However, if you need multiple processor concurrency, you can start these new processes via child_process.fork(), as well as other processes that have been scheduled in parallel. You can also find load-balancing for incoming connections across a variety of processes, using a cluster module. The cluster module is simply a single instance where Node runs in a single thread. In order to take advantage of this multiple core system, you may want to sometimes launch cluster of Node processes in order to properly handle the incoming load. This cluster module always allows you to create a network of processes quickly and easily, and allow each to share server ports.

You can also use Node in a runtime environment, to share port 8000 between your workers, as you can know exactly who is online. The difference between cluster.fork () and child_process.fork () is the simple fact that cluster will allow TCP servers the opportunity to be shared between workers, where cluster.4 is implemented on top of child_process.org. The passing message via API that is available with child is also available with cluster, and as an example, below is a cluster which provides a count of all of your requests available in the master process through message passing:

var cluster = require('cluster');
var http = require('http');
var numReqs = 0;
if (cluster.isMaster) { // Fork workers.
    for (var i = 0; i < 2; i++) {
        var worker = cluster.fork();
        worker.on('message', function(msg) {
            if (msg.cmd && msg.cmd == 'notifyRequest') {
                  numReqs++;
            }
        });
    }
    setInterval(function() {
        console.log("numReqs =", numReqs);
    }, 1000);
} else {
    // Worker processes have a http server.
    http.Server(function(req, res) {
        res.writeHead(200);
        res.end("hello world\n");
        // Send message to master process
        process.send({ cmd: 'notifyRequest' });
    }).listen(8000);
}

Cluster.fork is only available to spawning new worker process, and can only be initiated from the master process. You can also use Boolean flags in order to discern if your current process is a master or worker within your cluster, because a process is master, if your process.env.node_worker_ID is undefined. However, if one of your workers die, your cluster module will emit this death event, and it can also be used to restart worker, by calling fork () again. Although different techniques are available, each can be used to restore your worker depending on your application, death and master.

Currently, Node is being used in a variety of industries, including Microsoft, eBay, Cloud 9 IDE and Transloadit.
On Microsoft, it allows Azure users the opportunity to take advantage of end-to-end JavaScript experiences, providing a new class of real-time application development. Node’s event and I/O model has also provided a freeing from worry of locking and concurrency issues, which are extremely common with multithreaded asynchronous I/O.
With the opportunity to build real-time cloud platforms with a single language on both ends, anyone can write, run and debug code anytime, anywhere, from any mobile device.

In addition, node.js also allows execution of independent background processes without locking them. This is vital for file uploading and encoding, and providing a more extensive and innovative user experience. Regardless of your needs, industry networking, node.js is truly an innovative platform to build the fastest, easiest scalable network applications that is truly effective, regardless of data and devices.