How do I store session specific info in Socket.io?
var client={}; //is this static across all sockets (or connected clients) that are connected?
io.on('connection', function(socket){
client.connectiontime=Date.now();
});
//on another io.on('connection') for the same connected client
io.on('connection', function(socket){
store(client.connectiontime);
}
How do I use the client variable only for the operations related to the currently connected client if it is considered static?
First, each socket is given a name that can be used to refer to it, but that changes each time the same client connects so this would not be useful if it is supposed to remain after the client leaves. If your goal is to store the connection time somewhere (a database?) then you would have to get a unique identifier from the client that could be used to find them again similar to a login. You would then pass the date object into the function that handles storing that time.
You should note though, that 'connection' is only called the first time the socket connects. A connection is not the event you normally would be using for when a client does something unless they disconnects between each access of the server program.
If you are sure you want to just use the Client object, you would likely have to create a client array and use the socket id as a key to access the object later. You would then have something like
array[socket.id].connectiontime = Date.now()
var client={}; //is this static across all sockets (or connected clients) that are connected?
var clients = [];
io.on('connection', function(socket){
clients[] = {
id : socket.id
connectiontime : Date.now()
}
});
//on another io.on('connection') for the same connected client
io.on('connection', function(socket){
// Here you would search for the object by socket.id and then store
store(client.connectiontime);
}
Related
Im working on a simple session based app shared by a session code in the URL. I decided to generate and assign a shorter user friendly unique ID for each client who connects to a socket, and the client who creates a session causes a socket.io room to be created with his ID.
I didnt realize until later that the private messaging mechanism in socket.io relied on each client being assigned to a room named by their ID. This means that because my room for a session is named after the creator's socket ID, using .to() will not message that client, but rather all of the clients now assigned to that room.
I could remedy this in ways that would require some re-design, but first I wanted to ask if there is an alternate way of sending a message to a specific client via his/her ID.
/*create an array of clients, where key is the name of user and value is its unique socket id(generated by socket only, you do not have to generate it) during connection.*/
var clients = {};
clients[data.username] = {
"socket": socket.id
};
//on server side
socket.on('private-message', function(data){
io.sockets.connected[clients[data.username].socket].emit("add- message", data);
});
//on client side
socket.emit("private-message", {
"username": userName,
"content": $(this).find("textarea").val()
});
socket.on("add-message", function(data){
notifyMe(data.content,data.username);
});
So I'm connecting two variable (objects) to the same socket.io server, one's job is to handle public feed and another's to handle private feed with extended functions.
I've attempted the "force new connection" option, however both connections seem to still use utilize the same socket + session Id.
I originally didn't include code because this is so basic, but here you go:
var socket = io(host);
socket.on('connect', function(e){
socket.emit('join', {
channel: stream_channel,
});
});
One is var socket, the other is var socket2. When it connects to the server it emits "join" where:
io.on('connection', function(socket){
socket.on('join', function(d){
socket.join(d.channel);
});
});
I was able to figure this out by:
Subscribing the websocket to multiple rooms
Appending additional variables at each POST to define the room to emit to
I was able to determine that:
Utilizing the same host will always keep the same session id / socket (even with force connection enabled)
Potentially using a different host or namespace would allow a separation in connection
It's better to keep a single connection with multiple rooms
I have socket id of each connected user stored in my database. When any user posts a comment or status, I want to broadcast the same to all his/her connections using socket id stored in my database.
I can emit the message to individual client using his/her socket id by using io.sockets.connected[ socket.id ].emit('privateMsg', 'Hello! How are you?');
But how do I emit the same to the array of socket id which i have generated using select query from my database.
You can use concept of rooms. Whenever a socket connection arrives, join the connections to a room. And on disconnect, remove the socket from the room.
socket.on('connection', function () {
socket.join('room1');
});
socket.on('disconnect', function () {
socket.leave('room1');
});
Now when you want send messages to sockets connected on a room, you can broadcast it to room.
socket.broadcast.to('room1').emit('eventName', data);
You could dynamically create a room for each socket that connects and emit to it without having to loop over the entire array every time. Like so:
socketids.foreach(function(socketid){io.sockets.connected[socketid].join(sendingSocket.id);});
Then you can emit to those sockets from your sending socket by doing the following:
sendingSocket.to(sendingSocket.id).emit('publicMessage', 'Hello! How are you?')
As a side-note, I don't think keeping socket ids that change in a database is the best approach, since they have no persistence at all. You may want to try to find a better identifier for your database.
For anyone who visites this thread. After Socket.io 3.x we can pass arrays of room names and socket ids to io object. like this:-
socketIds = [xlksdf09sdfsk,sdosdifns90sdf,..........]
io.sockets.to(socketIds).emit('hello','recieving all sockets')
roomNames = [roomA,roomB]
io.to(roomNames).emit('hello','recieves each member of the rooms')
// Event is also not emmitted multiple times on the client side
// evern if single socketId is present in multiple rooms.
Is there a way to get the number of connections in socket.io?
I want to display a message on my site that says "x users connected right now"
Basically if I did a socket.broadcast I want to count how many connections that would go to.
You can use
io.sockets.clients().length
Basically io.sockets.clients() returns Socket instances of all clients. If you're using rooms then you should better use
io.sockets.clients('room').length
because it returns socket instances of all clients in a particular room
Using this code Server site
var noOfUser=[];
socket.on('someEventFromClient',function(data){
//User name must unique
socket.username=data.username;
noOfUser.push(data.username);
//Now you can emit no of user to client are any where
console.log('NO of user:'+noOfUser.length);
});
socket.on('disconnect',function(){
for(var i=0;i<noOfUser;i++)
{
if(noOfUser[i]==socket.username)
{
noOfUser.splice(i,1);
}
//Now you can emit no of user to client are any where
console.log('NO of user:'+noOfUser.length);
}
});
Client side:
when user connect socket server emit this event
socket.emit('someEventFromCLient',{username:'someuniqueID'});
I'm building a simple system like a realtime news feed, using node.js + socket.io.
Since this is a "read-only" system, clients connect and receive data, but clients never actually send any data of their own. The server generates the messages that needs to be sent to all clients, no client generates any messages; yet I do need to broadcast.
The documentation for socket.io's broadcast (end of page) says
To broadcast, simply add a broadcast flag to emit and send method calls. Broadcasting means sending a message to everyone else except for the socket that starts it.
So I currently capture the most recent client to connect, into a variable, then emit() to that socket and broadcast.emit() to that socket, such that this new client gets the new data and all the other clients. But it feels like the client's role here is nothing more than a workaround for what I thought socket.io already supported.
Is there a way to send data to all clients based on an event initiated by the server?
My current approach is roughly:
var socket;
io.sockets.on("connection", function (s) {
socket = s;
});
/* bunch of real logic, yadda yadda ... */
myServerSideNewsFeed.onNewEntry(function (msg) {
socket.emit("msg", { "msg" : msg });
socket.broadcast.emit("msg", { "msg" : msg });
});
Basically the events that cause data to require sending to the client are all server-side, not client-side.
Why not just do like below?
io.sockets.emit('hello',{msg:'abc'});
Since you are emitting events only server side, you should create a custom EventEmitter for your server.
var io = require('socket.io').listen(80);
events = require('events'),
serverEmitter = new events.EventEmitter();
io.sockets.on('connection', function (socket) {
// here you handle what happens on the 'newFeed' event
// which will be triggered by the server later on
serverEmitter.on('newFeed', function (data) {
// this message will be sent to all connected users
socket.emit(data);
});
});
// sometime in the future the server will emit one or more newFeed events
serverEmitter.emit('newFeed', data);
Note: newFeed is just an event example, you can have as many events as you like.
Important
The solution above is better also because in the future you might need to emit certain messages only to some clients, not all (thus need conditions). For something simpler (just emit a message to all clients no matter what), io.sockets.broadcast.emit() is a better fit indeed.