Is event based model used in node the same as the event based model used in C# applications?

Question

I've heard about node.js and event based programming and things like the node event loop. In college I remember that I made an ASP.net web application. The professor said that ASP.net uses an event based architecture where callback functions on the server side were triggered by different events on the client side.

Are the two different technologies using the concept for events and event driven programming?

Answer 1

They're similar in that they're both using the idea of events - something that calls your code, rather than you going out and looking for changes. But in practice they're quite different.

In node (and in asp.net MVC) the events in question from the client are "this URL was requested". That's it. There's no more granularity other than the contents of the request.

In ASP.NET Webforms, they work very hard to synthesize events based on what happened on the client page. The events you get are "text changed", "button clicked", "checkbox checked"... basically the same kind of stuff you'd get in a straight desktop app.

It turns out that the Webforms model gets really, really complicated really fast, and the abstraction layer gets in the way of doing things like ajax calls.

Another thing node does is that just about everything is async events, unlike ASP.NET. Database call? Async in node, sync in ASP.NET. Read a file? Async in node, sync in ASP.NET. HTTP request to another server? You get the idea.

ASP.NET can do those things async, but you have to go out of your way to do it, and it uses threads. In node the async stuff is pretty natural and it doesn't need to use threads, resulting (somewhat surprisingly) in higher throughput in some cases.

So yes, they're the same in the sense that they're both "events", but the details are staggeringly different.

Answer 2

Yes, node uses an event based architecture where callback functions on the server side are triggered by different events on the client side.

Why Node.js is a big deal.

1) Using the same language on the client and the server speeds development.

2) Every web developer already knows JavaScript. The transition path to using it on the server has a lower learning curve.

3) Modules built for Node.js are all event driven. Writing event driven code on other platforms usually requires you to sift through third party modules to find the ones that are event driven. For example, there are several event driven libraries for Python, but most third party networking libraries for Python are synchronous because of Python's heritage. Same with Ruby, Java, Scala and many other platforms.

4) Speed. Node.js runs on the V8 javascript engine. It may not be quite as fast as Java or C#, but it's light years ahead of Python, Ruby and PHP. Python, Ruby and PHP make up a huge portion of the web application market share. When developers with their primary experience based in those languages need more speed, Node.js is a logical place to find it.