#Introduction to socket.io

From the Youtube Video: Getting started with socket.io

Socket.io is a JavaScript library for realtime web apps

Install

• npm install socket.io

API

• socket.emit[{String} messageName, {Object} data]

  • Emits a message
  • socket.emit('myData', { key: 'My value' });

• socket.on[{String} messageName, {Function} callback]

  • Listens for a message to be sent
  • socket.on('myData', function(data) { console.log(data.key); });

• socket.send({Object} data)

  • A quick alternative for the emit method. The message's name will always be message
  • socket.send('Hello world');

• socket.set[{String} name, {Object} data, {Function} callback]

  • Setter
  • socket.set('myData', 'My Value', function() { console.log('myData set!'); });

• socket.get[{String} name, {Function} callback]

  • Getter
  • socket.get('myData', function(err, data) { console.log(data); });

• socket.broadcast.emit({String} messageName, {Object} data)

  • Broadcast a message
  • socket.broadcast.emit('myData', { key: 'My value' });

• Namespacing

  • Server side :
    • var io = require('socket.io').listen(80); var task = io.of('customNamespace').on('connection', function(socket) { task.emit('myData', {}); });
  • Client side :
    • var client = io.connect('http://localhost/customNamespace'); client.on('connect', function() { client.on('myData', function(data) { console.log(data) }); });

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Emit types from this question: Send response to all clients except sender

// sending to sender-client only

• socket.emit('message', "this is a test");

// sending to all clients, include sender

• io.emit('message', "this is a test");

// sending to all clients except sender

• socket.broadcast.emit('message', "this is a test");

// sending to all clients in 'game' room(channel) except sender

• socket.broadcast.to('game').emit('message', 'nice game');

// sending to all clients in 'game' room(channel), include sender

• io.in('game').emit('message', 'cool game');

// sending to sender client, only if they are in 'game' room(channel)

• socket.to('game').emit('message', 'enjoy the game');

// sending to all clients in namespace 'myNamespace', include sender

• io.of('myNamespace').emit('message', 'gg');

// sending to individual socketid

• socket.broadcast.to(socketid).emit('message', 'for your eyes only');