At a Glance

Connection is a new way of socket communication. It automatically converts sockets into client profiles and helps developer to associate personal data with each connected client. Also, Connection simplifies socket networking by asynchronous callbacks. The library is built on top of socket.io.

Important note. This is a server-side of Connection library. For client-side solution, take a look at JavaScript version.

How to Get Started

If you use npm, type in Terminal:

npm install --save @imatyushkin/connection

If you prefer yarn, type:

yarn add @imatyushkin/connection

Usage

Initial setup

Connection requires HTTP or HTTPS server instance:

const connection = new Connection({
	server: <HTTP or HTTPS server instance>
});

Clients

Instead of low-level sockets, Connection considers every client as instance of Client type. Every instance has:

• id: unique string that identifies client;
• socket: reference to socket object from socket.io library;
• data: optional object for storing client's data (do whatever you want with this object).

The list of existing clients is accesible via:

connection.getClients()

You can handle client-related events within the configuration of your Connection instance:

const connection = new Connection({
	server: <HTTP or HTTPS server instance>,
	clients: {
		onConnected: (client) => {
			/*
				Handle new client.
			*/
			console.log(`Added client with ID: ${user.id}`);
		},
		onDisconnected: (client) => {
			/*
				Handle client's disconnection.
			*/
			console.log(`Removed client with ID: ${user.id}`);
		}
	}
});

Request and Response

In socket.io, every message sent between client and server includes event name and (optionally) some data. In Connection library, we use a different way of communication: request and response. It's similar to regular APIs where we send data by HTTP channel and (sometimes) receive response.

To receive requests from client, set up your configuration:

const connection = new Connection({
	server: <HTTP or HTTPS server instance>,
	io: {
		onRequest: (request, respond) => {
			/*
				Handle request sent by client.
			*/
			let sender = request.from;
			
			if (request.data.requireGreeting) {
				/*
					We can send response to client by passing data to `respond` function.
				*/
				respond({
					text: `Hello, client "${sender.id}"!`
				});
			}
		}
	}
});

Sending request from server to client is super simple:

connection.send({
	to: "RECIPIENT-ID",
	event: "greeting",
	data: {
		text: "Hello!"
	}
});

Let's assume we want to say hello to the first client on the list:

let client = connection.getClients()[0];
connection.send({
	to: client.id,
	event: "greeting",
	data: {
		text: "Hello!"
	}
});

If you want to get response, add callback to the options:

let user = connection.getClients()[0];
connection.send({
	to: client.id,
	event: "greeting",
	data: {
		text: "Hello!"
	},
	callback: (data) => {
		/*
			Handle response from client.
		*/
	}
});

Also, we can say hello to all connected clients:

connection.everyone({
	event: "greeting",
	data: {
		text: "Hello"
	}
});

Conclusion

Here's an example of extended configuration for Connection instance:

const connection = new Connection({
	server: <HTTP or HTTPS server instance>,
	events: {
		defaultEvent: "CustomEvent"
	},
	clients: {
		onConnected: (client) => {
			/*
				Handle new client.
			*/
			console.log(`Added client with ID: ${user.id}`);
		},
		onDisconnected: (client) => {
			/*
				Handle client's disconnection.
			*/
			console.log(`Removed client with ID: ${user.id}`);
		}
	},
	io: {
		onRequest: (request, respond) => {
			/*
				Handle request sent by client.
			*/
			let sender = request.from;
			
			if (request.data.requireGreeting) {
				/*
					We can send response to client by passing
					data to `respond` function.
				*/
				respond({
					text: `Hello, client "${sender.id}"!`
				});
			}
		}
	}
});

Most of things presented in configuration are optional. You can combine necessary settings to get the server functioning right.

License

Connection is available under the Apache 2.0 license. See the LICENSE file for more info.