backend deployed at https://rens-chat-app.herokuapp.com/
backend source code: https://github.com/earthddx/ChatReact
In short, it allows instant messaging and chat.
Socket.IO's "Hello world" is a chat app in just a few lines of code. Sockets have traditionally been the solution around which most real-time chat systems are architected, providing a bi-directional communication channel between a client and a server. This means that the server can push messages to clients. Whenever you write a chat message, the idea is that the server will get it and push it to all other connected clients. Socket.IO is using this technology (basically, anything that is real-time could be done in a pretty simple way with it).
In order to get server running on your localhost you can do something as simple as:
const express = require("express");
const socketio = require("socket.io");
const http = require("http");
const PORT = 4000;
const app = express();
const server = http.createServer(app);
const io = socketio(server);
server.listen(PORT, () => console.log(`Server started on ${PORT}`));
eventName(String)argsack(Function)- Returns
Socket
Emits an event to the socket identified by the string name. Any other parameters can be included. All serializable datastructures are supported, including Buffer.
socket.emit('hello', 'world');
socket.emit('with-binary', 1, '2', { 3: '4', 5: new Buffer(6) });
The ack argument is optional and will be called with the client’s answer.
io.on('connection', (socket) => {
socket.emit('an event', { some: 'data' });
socket.emit('ferret', 'tobi', (data) => {
console.log(data); // data will be 'woot'
});
// the client code
// client.on('ferret', (name, fn) => {
// fn('woot');
// });
});
eventName(String)callback(Function)- Returns
Socket
Register a new handler for the given event.
socket.on('news', (data) => {
console.log(data);
});
// with multiple arguments
socket.on('news', (arg1, arg2, arg3, arg4) => {
// ...
});
// with callback
socket.on('news', (cb) => {
cb(0);
});
The socket actually inherits every method of the Emitter class, like hasListeners, once or off (to remove an event listener).
Used in the back-end.
socket.join(user.channel); //user gets inside of a channel
callback(Function)- Returns
Socketfor chaining
room (String)
err signature (if any).
io.on('connection', (socket) => {
socket.join(['room 237', 'room 238'], () => {
const rooms = Object.keys(socket.rooms);
console.log(rooms); // [ <socket.id>, 'room 237', 'room 238' ]
io.to('room 237').to('room 238').emit('a new user has joined the room'); // broadcast to everyone in both rooms
});
});
Used in the back-end.
socket.broadcast.to(user.channel).emit("message", {
user: "admin", //<--admin generated message-->
text: `${user.name} has joined the chat!`,
});
Sets a modifier for a subsequent event emission that the event data will only be broadcast to every sockets but the sender.
io.on('connection', (socket) => {
socket.broadcast.emit('an event', { some: 'data' }); // everyone gets it but the sender
});
Synonym of socket.close().
- Returns
Socket