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 (e.g. 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!
Related
I have a c# tcp server, I want to connect to the server via a html client page.
The problem: There is no simple way to create TCP sockets in Javascript on a browser side. Although solutions like Websockets allow to create something that resemble sockets, you can use them to connect only to servers that support Websockets. Not to any random servers that know nothing about HTTP.
so is there a solution to connect to my srver.
No. There just isn't. The browser is a tightly locked down environment. The only socket connection that you can open from JavaScript is WebSocket. Since it's your server, adding WebSocket support shouldn't be too complicated, and there are WebSocket libraries available for C#.
Maybe someone else will have an idea for you, but...
The best solution I can think of is for your server to support websockets.
The situation you described - along with connectivity issues for traffic passing through proxies and routers - is one of the reasons Websockets were introduced in the first place.
Bare in mind that Websockets can send and receive binary data. It's just that javascript make it more comfortable to write text based messages.
Also, many NAT routers, Proxies and firewalls will block raw TCP/IP communication while allowing Http communication to pass through. This is why you have a better chance at connection establishment and retention when implementing the Websocket protocol.
Basically, I want to make a peer to peer architecture, using JavaScript (Ionic).
Since, JS cannot create sockets/etc; a NodeJS server has to be introduced between the clients; acting as the Socket.IO server between the clients.
The problem with this, is that the Socket.IO (NodeJS) server would need to be automatically found within the local network -- by the clients (instead of hardcoded/configured).
Are there any ways to implement such a thing; or alternatives to this architecture?
Thanks for the help!
Are there any ways to implement such a thing; or alternatives to this architecture?
Currently your architecture is using a browser app plus a Node app that users need to have on their network just to create TCP connections.
What you can do instead is create an Electron app that combines a Node app, a browser app, and a browser itself. See:
https://electron.atom.io/
With Electron you can write your frontend code almost the same way as for the regular browser, but you can use the entire Node API including the TCP sockets so there will be no need to create a separate Node app and to search for that app in the network. This can greatly simplify your architecture.
Note: this is not an answer to the first part of the question: "How to detect a server in the network using JS?" but to the second part of the question: "Are there any ways to implement such a thing; or alternatives to this architecture?" Detecting the servers on the local network with client-side JavaScript will not be easy - and in fact it shouldn't be even possible because websites being able to scan your LAN for active services would be a serious problem for privacy and security.
I am interested to know if anyone has built a javascript websocket listener for a browser. Basically the server side of a websocket that runs in a client. This would allow messages to be sent to the client directly. Why? Because instead of having a Node.js, python, java, etc, server process sitting on or near the client/browser, I can just use a thread in the browser as a listening server thread. I don't think that any browsers support this currently.
I've run across answers like this: https://news.ycombinator.com/item?id=2316132
Just curious if anyone has done this. I believe that the current Websockets spec does not support listeners on the browser. It would make the deployment of various peer-to-peer applications a bit easier to deploy.
WebRTC allows for peer-to-peer connections to be made between browsers.
You would still need a server in order for individual users to discover each other but then they could connect directly to each other rather than having to pass all their traffic via a central server.
The idea.
You can use a simple echo server written in any language. Your script can send the data to the server then get it back, handle it on the same page with different functions/classes emulating the real server.
An example: http://www.websocket.org/echo.html
Then, you can think about different formats of packets to/from server to diffirentiate them inside one script.
I'm using python (Tornado) on server side and some javascript on a client side. I have the common situation - one user send a message to another. And I want server to notify client's browser (reciever of the message) about new message. How can I do it? Should I establish long-alive connection with client (maybe using websocket) or something else?
PS
For establishing conenction via websocket I found good library TornadIO
PS2
So, due to high load of project establishing connection betwebb server and each client looks suspicious. I afraid of c10k problem. May be it's only lack of my knowledge.
I'm using python (Tornado) on server side and some javascript on a client side. I have the common situation - one user send a message to another. And I want server to notify client's browser (reciever of the message) about new message. How can I do it? Should I establish long-alive connection with client (maybe using websocket) or something else?
Using a realtime web server such as Tornado - yes. TornadIO looks like a good solution since it'll use socket.io which has fallback options for older browsers.
The Wikipedia entry on the C10k issues provides a list of servers that have resolved this problem:
A few web servers have been developed to counter the C10K problem:
nginx, which relies on an event-driven (asynchronous) architecture, instead of threads, to handle requests (WordPress.com uses nginx to solve the C10K problem)[2]
Lighttpd, which relies on an asynchronous architecture to handle requests[3]
Cherokee, a lightweight web server[4]
Tornado, a non-blocking web server and web application framework[5] written in Python
Apache Deft, asynchronous, non-blocking web server running on the JVM
JBoss Netty, a NIO client server framework which enables quick and easy development of network applications such as protocol servers and clients[6]
Node.js, asynchronous, non-blocking web server running on Google's V8 JavaScript engine[7]
EventMachine, an asynchronous, non-blocking web server running on Ruby EventMachine
Yaws, a web server written in Erlang; profiting from Erlang's extremely lightweight processes.
Medusa, a non-blocking web server library written in Python
As you'll see, Tornado is listed.
Beyond this your question is potentially more about horizontal scaling than it is about how to achieve server to client notifications.
Depending on which realtime server solution you choose this might never become an issues. For example, a single instance of Caplin System's Liberator can achieve a lot more than 10,000 persistent connections.
This question follows a previous one: Shall I use Node.js Instead of Rails for Real-time WebApps?
The question:
What's the best way of communicating between a Rails app and a Node.js app in order to take advantage of both technologies?
Thanks
Why not open a TCP socket for communication between node & RoR ?
var net = require('net');
// create TCP server
var server = net.createServer(function (socket) {
// write down socket
socket.write("Echo server\r\n");
socket.pipe(socket);
})
// start server listening on port 8124
server.listen(8124, "127.0.0.1");
And in RoR you can connect to the socket
require 'socket' # Sockets are in standard library
hostname = '127.0.0.1'
port = 8124
s = TCPSocket.open(hostname, port)
while line = s.gets # Read lines from the socket
puts line.chop # And print with platform line terminator
end
s.close # Close the socket when done
Then just write an abstraction on top of this TCP socket to synchronize your communication nicely and without requiring low level fiddling.
Why do the apps need to communicate?
If you simply need a Rails app to get some realtime data into the browser, then using a node.js server app and Socket.IO would be sufficient.
You have to remember that any Rails apps, is actually two applications, one written in Ruby running on the server, and one written in Javascript running on the client. They usually communicate over HTTP, sometimes with AJAX and sometimes not. Which part of your app needs the functionality of node.js?
If it is the case that the app deals with login, then displays a web page, and then continually refreshes that web page with real-time data, you only really get a benefit from node.js for the realtime data refreshes whether you do it with AJAX polling or with Websockets. Shared databases are a nice way for apps to communicate, but not for realtime.
To make it clear, if you are an expert in Ruby with Rails, you will be more productive if you add a node,js server app and only use it for high-volume data, such as realtime updates. You then have a hybrid web app that leverages the best of both platforms.
What about keeping Rails and use Faye?
the latest Railscast is awesome: http://railscasts.com/episodes/260-messaging-with-faye
One way is to have a common back-end database or some kind of memory storage which will act as intermediary layer between the two technologies. Popular is for example to use NoSQL DB like Redis which is fast, memory based and supports advanced data structures which are handy for this scenario. Also node.js and RoR both have a good client libraries for communication with Redis.
I would say the main problem is in initial authentication between the two separate systems which both needs to be synchronized. There are similar questions/answers related to this topic which may come useful to read, for example these two shows what are the possible ways how to solve the authentication problem.
It depends on exactly why you're separating the functionality from one to the other. Rails supports REST based separation without any extra work on your part. It's built based on resources from the ground up. That means it would be very simple for you to use an http.Client (or something like Restler) to query against it. You can certainly do the exact same the other way around, using standard Node.js routing (or something like Express) and an HTTP client for Ruby (such as Typhoeus). Though this method incurs the overhead of using a full HTTP request (not necessarily a problem if on an internal network). If you are looking for a more speedy way of communication, I'd say you could go about it using a persistant socket as Raynos suggests.
Depending on your need, I would suggest that using two separate systems creates extra code complexity, and it may be best for you to reduce it to one framework/language. I'm all for Service Oriented Design, but Rails is a pretty heavy weight and may slow down your over all response times, even with having Node.js working with it.