What role does Socket.IO have with Node.js
I'm fairly new to the world of JS and its abundance of libraries. I'm looking to get into a project that involves network communication (sockets) between clients and a server. In a world with tons of libraries, I cannot make a decision as to which to use. I'm looking for something that will bring efficiency and stability.
I've been told that Node.js is like the middleman between you, as the developer, and Socket.IO. I've been told it's a huge framework that you may not use at least half of. I've been told that to maximize efficiency, you're better off using Socket.IO to make your own functionalities. I've done some research on my own and found that Socket.IO NEEDS Node.js and Node.js DOESN'T NEED Socket.IO. Which is completely opposite of what I was told. Then I find that most developers use both Socket.IO and Node.js at the same time?
Like I said, I'm fairly new, but I cannot find the right resources that would help me accomplish a websocket communication between a client and a server with maximum efficiency, or at least explain the difference between Socket.IO and Node.js. If anyone here could, please let me know! I would greatly appreciate it.
node.js is a general purpose javascript-based run-time environment (somewhat similar to other language runtimes like python in scope). You can create apps in it that don't even use the network. It is often used as a web server for created web apps and has a great set of tools and rich library of add-ons for doing so. It does not need socket.io.
socket.io is a specific library to enable web-socket-like communication between a client and a server (eg a chat room app is the canonical example). The server side of socket.io assumes a javascript run-time (because it's written in javascript) so that generally means node.js (though I'm not sure if a different JS runtime could perhaps be substituted).
You can think of node.js like the platform and socket.io like a specific tool to do a specific job that runs on that platform. You would use socket.io (on top of node.js ) if you needed web socket connectivity between client and server.
You would use only node.js if you need any of the other things node is good at, but did not need websocket connectivity.
websockets themselves can be programmed on the server side without socket.io and without node.js. They could be programmed in strait C++ or in Java. But socket.io (running in node) provides a very easy way to set them up because the socket.io library covers both client and server in one library and one API and it's all in the same language (javascript). Look at the chat room app example on the socket.io site and you will be unlikely to find any other solution that can accomplish that in as few lines of code as it does and with the same interface on client and server.
If you were only setting up a websocket server (no web server or web app of any kind), you could still use node and socket.io and use it just for the websocket server and it would still be quite efficient. While node is capable of doing lots of other things, if you don't configure and install all those other things, they aren't costing you anything - they are just unused capabilities that aren't running.
I should add that one other thing the socket.io library does is it handles an auto-negotiation between client and server to find the best channel for the client and server to communicate on. If websockets are available, then socket.io will likely use them, but if web sockets are not available, socket.io has alternate methods that will work (even in older browsers). That functionality comes for free in socket.io without you even doing anything.
In case this isn't completely clear to you, websockets are typically used to provide real-time communication between client and server. While clients can ask for data from a server at any time with an ajax call or a web page request, what websockets allow is a two way real-time communication between client and server and the biggest advantage of websockets is that a server can send a client real-time data at any time while they are connected.
For example, I have a web page that receives real-time data from my server anytime the web page is open. The web page is served over the typical node.js web server installation, but the real-time data is sent from server to client over a websocket connection.
In addition, if there's a chatty conversation happening between client and server, websockets can be much more efficient than a series of ajax calls because with a websocket, a connection is opened once and used repeatedly whereas with ajax, each successive ajax call is like a new connection.
Node.js is a runtime environment. It's a javascript engine with a standard library built around asynchronous I/O. It plays the same role that Java, Python, Ruby, .NET, etc., play for many other web applications.
I've been told it's a huge framework that you may not use at least half of.
It might be true that most people never use most of the standard library, but I wouldn't think it's more true of Node.js than other runtimes. "Framework" isn't an accurate word to describe it.
I've been told that to maximize efficiency, you're better off using Socket.IO to make your own functionalities.
Whoever told you that was mistaken, or meant that to maximize efficiency, you're better off using [Node.js and] Socket.IO [instead of other solutions]. Many other non-Node.js solutions require a single thread or process per connection, which limits the number of simultaneous connections a server can handle. Node.js is built around asynchronous I/O which is better for keeping many connections open at once, and Socket.IO is a library for Node.js for using WebSockets.
TL;DR: Socket.IO can fire events in realtime between your client and server, so there is no need for you to reload the page to notice something changing. This can be used for "live" applications like collaborative drawing, live chats, online games and more!
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