I'm using socket.io to handle some of the server-client communication and matchmaking for a simple multiplayer game.
(for now) im automatically joining 2 players together by adding them into a socket.io room. When a room has 2 players in it I emit a "startGame" event to the room using socket.to(ROOM).emit(EVENT, EVENT_MSG) after doing a check
server side nodeJS:
game_start_state = checkRooms(socket, freeRooms);
if (game_start_state){
console.log("told room", game_start_state, "to start their game!")
socket.to(game_start_state).emit("startGame", game_start_state);
}
but so far only the first socket that gets connected to the room receives the "startGame" event message, I've looked around and havent seen anyone else with the same problem. Below is the code that is fired after the client emits an event saying it wants to join a room.
server side nodeJS:
function checkRooms(socket, roomArray) {
// auto-matchmaking logic
if(!roomArray || !roomArray.length){
//if there is no room with space create a new one
const room = uuid();
r_list.push(room); // r_list is just an array used to keep track of opened rooms for displaying to the user through some html
freeRooms.push(room); // freeRooms is an array with rooms with just 1 socket connected
joinRoom(socket, room);
return(null);
} else {
// if there is a room with a space, try to connect the client to it
const room = freeRooms[0];
console.log(socket.id, "wants to join", room);
// connect client to rooms
joinRoom(socket, room);
// room is now full so start the game
freeRooms.pop(room);
return(room);
}
}
because for now there is only auto matchmaking, there will only be 1 room in the freeRooms array so I'm not worries about this.
Does anyone know where I could be messing up? Can provide more code examples if necessary.
socket.to(room).emit(...)
sends to every member of the room EXCEPT the referenced socket. You can see that documented here.
If you want to send to everyone in the room, then use:
io.to(room).emit(...)
How to send message instead to all clients in room, to specific user in default room based on username or id. Where I need to implement that, only on server site or? I know I am doing wrong and I am confused.
var numUsers = 0;
io.on('connection', (socket) => {
var addedUser = false;
// when the client emits 'new message', this listens and executes
socket.on('new message', (data) => {
// we tell the client to execute 'new message'
socket.broadcast.emit('new message', {
username: socket.username,
message: data
});
});
I see in docs that code https://socket.io/docs/rooms-and-namespaces/ and how can I handle the ID for users, they changed in every re-connection
Here is what you can do:
1.You can use your own data structure to store users information like socketId and other things or go for redis it is a good in memory data structure.
2.You have to store socketId for each user when a new connection is made on server using any of the above or some other method.
3.when you want to send the message to a particular user you need have it's socketId and use this code to send message:
io.to(`${socketId}`).emit('hey', 'How are you');
4.When a user disconnects just delete the user's info like socketId and other info which you have.
So, when a user join your server save his info and when he leaves just delete it.
Now suppose you have four users connected on your server. just create a array of object to keep the track of users and socket ids. when new user connects just push into the array and when a user exit just loop through the array and when socketId matches just remove that object from array simple
let users = [{name:'a',id:'socketId'},{name:'b',id:'socketId'},{name:'c',id:'socketId'},{name:'d',id:'socketId'}]
if you want to send message to user b only just loop through the array and match the name property and when you find the matching name just fetch the id of that user and send it away
for(let i=0 ; i<users.length ; i++){
if(users[i].name == 'b'){
io.to(users[i].id).emit('hey', 'How are you');
}
}
Every connection has a socket id but it will be different every time a user opens a new tab on the browser. So if a user opens two tabs, they will have two different socketIds.
So the better approach would be to use rooms. Every time a user connects you can add it to a room. The room name can be userId or email.
socket.join(userid)
Then whenever you want to send a message to a particular user just use
io.sockets.in(userid).emit('message',"hello");
This will work even if the user has multiple tabs open on their device.
So I have chat app in which only two users can be in a room at a time.
Please note that clientInfo is a global variable and anytime a new user joins a room, an object variable is passed to the server with username and room name. Then this code is executed
socket.on('joinRoom', function(userDetails){
clientInfo[socket.id] = userDetails; //variable contains name and room joined.
socket.join(userDetails.room);
}
I added a feature where a user can type 'kick' as the chat message which will call this function:
function kickUser(socket){
socket.leave(clientInfo[socket.id].room);
delete clientInfo[socket.id];
}
the above code works fine but how can i change the function to kick the other user in the room? I tried the code below but I still ended up kicking myself out. I take it that socket.leave() doesn't care about the socket id but it just uses the room name and the person who called the function.
function kickUser(socket){
var info = clientInfo[socket.id];
if (typeof info == 'undefined'){
return;
}
Object.keys(clientInfo).forEach(function(socketId){
if(info.room == clientInfo[socketId].room) {
if (info.name != clientInfo[socketId].name){
socket.leave(clientInfo[socketId].room);
delete clientInfo[socketId];
}
}
});
}
Try implement next idea
In socket.on('connection', function(socket){ ... }); you must identify user name and room for this connection/socket: client can send username/room on connection itself
socket.on('connect', function {
socket.send(JSON.stringify{do: "introduce", name: "User1", room: "dasRoom"})
})
or server can read it in client cookie. Also you can check here user count in room. This info can be stored in global vars.
User can do kick by send specified message by socket, e.g. {do: "kick
, user: "User1"}, or request url. e.g. /kick/User1.
Function Kick must implement logic to find user by name, send goodbay message to victim and disconnect socket. Also server must send User1 leave room to alive user by socket.
My goal is to create a one to one chat based on two different users. The only way that I could think of is to use socket.io rooms
But the problem right now is that how do i create unique room?
For example
socket.on('join', function(room) {
socket.join(room);
});
Do i need to emit the room from the client, if so , how do I make it unique. Imagine there are thousands of users.
The chat application, is similar like facebook chat application. Where you can chat one on one.
Do i need redis or mongodb to store the room? Anyone of you who have experience using socket.io in scale, please do share your opinion
Thanks!
A room always will be unique, when you do socket.join('roomname') if the room not exist it will created and this socket will join it, if exist the socket just will join it.
So if you want that client A join in the room where is client B for example, from client A you can send a event like:
socket.emit('joinroom', roomname);
On sever:
socket.on('joinroom', function(data){
socket.join(data)
})
Anyway when a socket connect , it create and join his own room automatically , the name of this room will be the id of the socket, so i think is not neccessary create new rooms for a chat based on two different users.
Everything that you need is link the socket id with a permanent property of the user.
EDIT:
I leave you here a simple chat app example where you can open multiple conversations:
server.js: https://gist.github.com/pacmanmulet/b30d26b9e932316f54b2
index.html: https://gist.github.com/pacmanmulet/6481791089effb79f25f
You can test it here :https://chat-socket-io-example.herokuapp.com/
I did not use rooms, it have more sense when you want emit to a group of sockets, not to a only one.
Hope you can understand better my idea with that.
you need to store the room number somewhere(any database).You have to do this because you have to keep your server stateless.
Let us assume that you are creating a private chat only for two people.The room number has to be unique. so one approach is to use the user's email id and join them to create a new string and emit it back to the users.this is tricky because we don't know the order in which the strings are joined. so we join them by a string not used in normal email name(eg :'"#!#!#!!#!#!#!').we can split it on the server side and compare emit the results.
The actual message body will be
{
room:a#gmail.comb#gmail.com,
from:a,
message:'hi buddy how are you?'
}
CLIENT side code
const roomName = a#gmail.com+'#!#!2!#!#"+b#gmail.com
socket.emit('room', { room: roomName });
this.socket.on('joined', data => {
console.log('i have joined', data.room)
store the room name room: data.room })
})
socket.on('chat',data=>console.log(`received chat from ${data.from} from the message room ${data.room}`)
used '#!#!2#!#' just because we can separate them on the server side and check if the room already exists.
SERVER side code
const room =[]//this variable you have store in database and retrieve it when needed.
socket.on('room',data=>{
if(room.length!=0){
const temp = data.room.split('!#!#2#!#!').reverse().join('!#!#2#!#!');
if(room.includes(temp)){
socket.join(temp)
console.log('joined room',temp)
socket.emit('joined',{room:temp})
console.log(room);
} else if(room.includes(data.room)){
socket.join(data.room)
console.log('joined room', data.room)
socket.emit('joined', { room: data.room})
console.log(room);
}
}else{
socket.join(data.room);
room.push(data.room)
console.log('joined room',data.room);
socket.emit('joined', { room: data.room })
console.log(room);
}
})
I tried to do a minimal example of where you can only be in one room at a time (apart from your default socket.id room) and only other sockets in the same room as you will receive your messages. Also you can change rooms.
The basic premise is, if socket A is in room 'xyz' and so is socket B, on the server side you can do socket.to('xyz').emit('message', 'hello') for socket A, and socket B will receive the message, but another connected socket C which isn't in room 'xyz' won't.
You can create room at server runtime, I used both users id as room id, Ex : '100-200' for demo purpose. May be you can use some more complex approach.
I just started learning NodeJS and Socket.io. Until now I have this demo code, from official socket.io site:
http://socket.io/demos/chat/
I am able to get the unique client's ID of each user (socket) which connects, I am still trying to figure out, How can I make my code to only connect with 1 random user at a time when somebody runs the application. I just want to make random chat like Omegle (http://www.omegle.com/).
Only two users should randomly connect and chat with each other till they re-run the app, if they come back they should get connected with someone else who is in the online queue.
What changes do I need to do to have a similar behaviour?
Update
Added Client site code, main.js
$(function() {
var FADE_TIME = 150; // ms
var TYPING_TIMER_LENGTH = 400; // ms
var COLORS = [
'#e21400', '#91580f', '#f8a700', '#f78b00',
'#58dc00', '#287b00', '#a8f07a', '#4ae8c4',
'#3b88eb', '#3824aa', '#a700ff', '#d300e7'
];
// Initialize variables
var $window = $(window);
var $usernameInput = $('.usernameInput'); // Input for username
var $messages = $('.messages'); // Messages area
var $inputMessage = $('.inputMessage'); // Input message input box
var $loginPage = $('.login.page'); // The login page
var $chatPage = $('.chat.page'); // The chatroom page
// Prompt for setting a username
var username;
var connected = false;
var typing = false;
var lastTypingTime;
var $currentInput = $usernameInput.focus();
//Own Global
var room = '';
var socket = io();
function addParticipantsMessage (data) {
var message = '';
if (data.numUsers === 1) {
// message += "there's 1 participant";
// Status Message
message += "Waiting to connect with someone";
} else {
// message += "there are " + data.numUsers + " participants";
//Status message update
message = "You are connected to a stranger! Say Hey!";
}
log(message);
}
// Sets the client's username
function setUsername () {
username = cleanInput($usernameInput.val().trim());
// If the username is valid
if (username) {
$loginPage.fadeOut();
$chatPage.show();
$loginPage.off('click');
$currentInput = $inputMessage.focus();
// Tell the server your username
socket.emit('add user', username);
// Own
socket.emit('login', {'username' : 'Faizan'});
}
}
Although I would close this question because it's too vague, I feel obliged to give you some insight since I worked way too much with websockets in the last years (although not that much with socketio & nodejs). I suppose some simple guide and relevant links could help you. So first,
Kind of relevant intro
You should already know that Socket.io is a WebSocket implementation.
WebSockets (WS) allow server to send data whenever it wants, as long as the connection is still open, as opposed to old way: client querying all the time asking, if there is an update on the server.
You can imagine a woman and a man at the end of a party: "Thanks for tonight, I'd love to repeat it sometimes soon. Would you give me your number?" - asks the old man. "Ughhh, you know what, better give me yours, I promise I will call you!"
If the girl were to give him her number, he'd call a few times a day asking if she'd go somewhere (and she'd reply no). The other way around, she would call him only if she wanted to go and he would go. Of course he would.
I got a bit carried away, but you get the picture. The woman is a server, the guy is a client.
What is important to understand
(Absolute basic, you should know this =>)
When client connect to your server, (s)he should be served a html page and some javascript, which establishes connection to your WS server. In the code you've posted, Express is used as http server. Check this example to see how you should give user html&js.
You'll also notice namespaces and rooms in most of these tutorials. These are used for separating users into subcategories. One server may contain multiple namespaces (by default only one) and each namespace may contain multiple rooms. You probably won't need to bother with namespaces, one is just enough for your case. You will, however, need to understand rooms (more on that later).
Next thing, taken from your code
io.on('connection', function (socket) {
It's important to know, that socket here basically represent one connected client (in one namespace, but possibly in multiple rooms). You can do all sort of stuff with it, most notably:
install event handlers on it (that's what you do when you call socket.on(event, handler(data))
send events to it with socket.emit(event, data)
send broadcast event to all users with socket.broadcast.emit(event, data)
add/remove it to/from room with socket.join(room), socket.leave(room) respectively.
work with it as with an ordinary variable - store it wherever you want and then reuse it
Do you see the definition of numUsers in your code? That's a global variable which is shared with all clients, since nodejs is single-threaded. In the example it is being incremented inside one of the event handlers. Think we could use something like that? YES.
We can define global variable, queue for example. Or Q if you want. Point is, it can be an array used to store sockets, or rather clients, which are not currently in chat room.
At the end of this section I'd like to point out another obvious thing.
io.on('connection', handler); defines an event handler for 'connection' event happening on the io object (WS server). This is triggered each time client makes connection to your WS server (in your case, through javascript ran inside client's browser). Argument to the method is socket and it is this method where you should add event listeners for each client (that you already do in the code, particularly handling events 'new message', 'add user', 'typing', 'stop typing' and 'disconnect').
What events shall you need
That really depends on how complex you want your app to be. In my opinion, the bare minimum would be (note that you can change the event names, but 'disconnect' should stay 'disconnect'):
event name -> data given
Events handled on server side
login -> username (how the user should be called), possibly password if you want to enable registration
message -> text (content of the message being sent)
leave room -> room name
disconnect
Event handled on client side
connect
chat start -> name (second client's name), room (so we can leave it)
chat end -> no data required if you want to allow only one chat at the same time. In case of multiple chats you should also include which chat got closed
disconnect
Last note before we get started
This is only a rough sketch. There are multiple different crossroads along the way and which path you take mostly depends on your idea of the app. If you want to have multiple chats opened at the same time, you'll need to do some modifications. The same goes if you want to have more than two people connected to the same chat. Here I'll describe the simplest case possible, one chat, to people, no registration. Possibly what you want, judging from your post. Could be wrong.
Workflow
User opens your page in their web browser. You serve them html and javascript. The javascript will start new connection to your websocket server. Also, handlers for desired events should be defined at this point.
When the connection is established, this will be happening:
ON SERVER SIDE
io.on('connection', handler) will be fired. Only appropriate handlers for new socket will be installed, not doing anything else at this point.
ON CLIENT SIDE
socket.on('connect', handler) will be fired. Client should at that point have username stored somewhere. If not, no problem. The connection will be alive for quite some time. You can just call socket.emit('login', {'username':name) any time you wish after you are connected (in the example below I set up variable connected, which defaults to false but will be set to true as soon as connection is established.)
After you send login event from client, server registers it and saves it somewhere. Possibilities are endless, in this case I'll create global dictionary which maps socket.id to username. After that, user socket should be either paired with another one or added to queue.
So, if the queue is empty, simply append socket to global variable (it doesn't have to be an array, since we will pair the first available sockets together, however you may want to implement some history of users so they won't get connected to the same person again). If the queue is not empty, we pull one socket out of the Q and add them to the same room. Room name can be random or whatever you want, I'll use (socket1.id+'#'+socket2.id (if you wanted to have more users in one chat, this would have to be changed).
After you add them both, you'll need to notify them that their chat has started and send them the other peer's name. You will emit event 'chat start'.
Clients will catch the event and open new window. After that, whenever user types something and sends it, client emits event 'message' with payload {'message': user_inserted_text}. Server will capture it in the .on('message' handler and broadcast it to the room. Note:
Broadcasting means sending a message to everyone else except for the socket that starts it.
Note: I am really confused about socketio code right now. Look at this and tell me, if socket.rooms is an array or an object (socket.rooms[room] = room; ?? why?)
To avoid dealing with this not-straightforward code, lets create another global object, rooms, which will store the room names for us. We will map socket.id -> roomName there.
So when message comes, we can get name of the room by calling rooms[socket.id]. Then we broadcast the message like this:
socket.broadcast.to(room).emit('message', data);
Where data is what we received from the sender, therefore object {'text': 'some nice message'}. Your peer will then receive it (you won't) and display it (you should display it when you are sending it).
So the chat continues like this for a while, then one of the users decides (s)he wants to leave / chat with somebody else. They will close window and client will emit event 'leave room'. Server will capture it and send to the other party that her/his peer has disconnected. The same should happen if the client disconnects. After everything is closed, add both users to queue (or only one, if the other has disconnected from the server). In my code I will not make sure they won't get paired again. That is for the OP to code (can't be hard).
So, if you read this far, you deserve some actual code. Although I say actual, it's actually untested. But you know, it should work like this.
Some code
Client side
var connected = false;
var username = 'Faizan';
var room = '';
var socket = io('http://localhost');
socket.on('connect', function (data) { // we are connected, should send our name
connected = true;
if (username) socket.emit('login', {'username' : username});
});
socket.on('chat start', function(data) {
room = data.room;
show_chat_window(data.name); // some method which will show chat window
});
socket.on('chat end', function(data) {
hide_chat_window(); // this will close chat window and alert user that the peer ended chat
socket.leave(room); // it's possible to leave from both server and client, hoever it is better to be done by the client in this case
room = '';
});
socket.on('disconnect', function(data) { // handle server/connection falling
console.log('Connection fell or your browser is closing.');
});
var send_message = function(text) { // method, which you will call when user hits enter in input field
if (connected) socket.emit('message', {'text': text});
};
var leave_chat = function() { // call this when user want to end current chat
if (connected) {
socket.emit('leave room');
socket.leave(room);
room = '';
}
};
Server side
Not including initial requires and html/js serving., only global definitions and main io handler.
var queue = []; // list of sockets waiting for peers
var rooms = {}; // map socket.id => room
var names = {}; // map socket.id => name
var allUsers = {}; // map socket.id => socket
var findPeerForLoneSocket = function(socket) {
// this is place for possibly some extensive logic
// which can involve preventing two people pairing multiple times
if (queue) {
// somebody is in queue, pair them!
var peer = queue.pop();
var room = socket.id + '#' + peer.id;
// join them both
peer.join(room);
socket.join(room);
// register rooms to their names
rooms[peer.id] = room;
rooms[socket.id] = room;
// exchange names between the two of them and start the chat
peer.emit('chat start', {'name': names[socket.id], 'room':room});
socket.emit('chat start', {'name': names[peer.id], 'room':room});
} else {
// queue is empty, add our lone socket
queue.push(socket);
}
}
io.on('connection', function (socket) {
console.log('User '+socket.id + ' connected');
socket.on('login', function (data) {
names[socket.id] = data.username;
allUsers[socket.id] = socket;
// now check if sb is in queue
findPeerForLoneSocket(socket);
});
socket.on('message', function (data) {
var room = rooms[socket.id];
socket.broadcast.to(room).emit('message', data);
});
socket.on('leave room', function () {
var room = rooms[socket.id];
socket.broadcast.to(room).emit('chat end');
var peerID = room.split('#');
peerID = peerID[0] === socket.id ? peerID[1] : peerID[0];
// add both current and peer to the queue
findPeerForLoneSocket(allUsers[peerID]);
findPeerForLoneSocket(socket);
});
socket.on('disconnect', function () {
var room = rooms[socket.id];
socket.broadcast.to(room).emit('chat end');
var peerID = room.split('#');
peerID = peerID[0] === socket.id ? peerID[1] : peerID[0];
// current socket left, add the other one to the queue
findPeerForLoneSocket(allUsers[peerID]);
});
});
P.S.
The code above got a bit messy in the end. It can be done better and I encourage you to do better job than I did. Having this material at hand, go through it step by step and try to understand. I think I commented most, if not all of it. Good luck.
Tl;dr
I am not even surprised. Here, read a comic