I am trying to integrate real time notifications with Node and socket.io in a Symfony Application. I have read a lot of information about this topic and have a working Node application.
nodeClient.js
var socket = io.connect( 'http://192.168.15.106:8080' );
$('a.sendSmile').click(function(){
socket.emit( 'message', { name: 'something' } );
});
socket.on('message', function(data){
console.log(data.name);
});
The problem now is with the above which is working perfectly I am able to send real time notification to all the users at once. But what's the best way to target a single user?
For example a user can send a smile to another user so only the second user should receive the notification and not all the users.
Should I make multiple listeners for node? or any other method to do this?
You need some way of identifying which socket that connected to your server is the one you want to send data to and then you can send to just that socket. You can keep track of user names when users connect or if you have some auth system, you can keep track of which socket belongs to which authenticated user.
Your server holds a list of connected sockets. Each connected one at a time and triggered a connection event on your server when they connected. Your application needs to create a way of knowing which of those connected sockets you want to send the data to. This is not something you've described anything about how you want that to work so we can't really help more specifically.
You can dispatch a notification to single user if you can discriminate that user. For example you can get a user_id on client connection to your nodejs server (the user_id is send from client, inside message) and save it in a key-value store (like Redis, memcache, ...). In this way you can correctly dispatch the notification, arrived from the server (like Symfony2 application), to right user.
I suggest you use Redis, both as a key-value store and for its implementation pattern of the publish/subscribe usable as a channel of communication between the server and the application of realtime.
Related
I am developing ionic mobile application with node js backend.
The problem is, I want to create dynamic topics with user's username or unique id to send data from server to mobile app.
what is the best way to do this task. any ideas or reference?
I found the solution for this task,
In the server created json array with name and the socket id.
Then every time new user connect to the server push new user to the array with respective socket id.
When emiting message go through the array, get socket id and emit to the specific user.
//sending to individual socketid
socket.broadcast.to(socketid).emit('message', 'for your eyes only');
you can find common socket commands from here:
credits to https://stackoverflow.com/a/10099325
I have multiple processes & servers, and am using socket.io-redis with session affinity (on Heroku).
When a client connects, I store a map of the client's user ID to the client's socket ID in Redis. Upon disconnecting, I delete the client's user ID from Redis.
I would like to be able to push a message to a client by looking up the client's socket ID, then sending a message to the specific socket ID.
One way to do this is io.to(socketId).emit(...). However, this does not allow me to send a callback with the message, which I would really like because I want to have confirmation of message receipt.
Another way I have found is io.connected[socketId].emit(...). The problem with this is that it does not scale to multiple servers, since the io.connected object may not necessarily be the same on every server since it only records sockets that the server itself is connected to. This solution does allow callbacks, however.
Is there a way to solve this so I can emit messages to a specific socket ID from any server or process, and also send a callback with the message?
Good afternoon,
I have a chat application written with NodeJS, Express and socket.io, in that application there are no rooms, when a user connects the socket (connection of that user) is linked to his id in an object that stays in memory:
Users = {
'1': {socket},
'2': {socket},
...
}
This works great! When a user is going to send a message it informs the recipient's id the server retrieves the equivalent socket and sends the message.
My problem is that due to the number of users I will have to upload a new server with the application, the problem is that users on different servers can not communicate because each server knows only the list of users that is connected to it. After much reading I came to the conclusion that the best way to solve this is by using the Redis Adapter, I looked for examples on the internet exhaustively however they all use Rooms to send the messages or send the same message to all the user and I would like to send one Message to a specific user regardless of which server instance it is if possible without the need to create rooms, simply recovering its connection based on its id and sending the message, would like to know if someone could tell me if this is possible and how to implement.
Below is an image of how my architecture should look:
In our app, every time a user signs in a new connection in socket.io is created. So if a user signs in simultaneously on more devices, they behave as separate connections. Instead of creating a new connection every time, I'd like to check whether the user is already connected to socket.io and if he is, I'd like to connect him to already established connection. How can this be done?
From the socket.io perspective, those ARE two connections. But if it was my app, I would do something like this:
add a user identifier (userid, username, something you identify users by) to both the users' socket.io connection (so, each time you send a message to the client, you also pass this id)
pass this id also to the client-side code on init.
So now the socket on the server side has its' socket.io id, but also your user id. Anyway, to proceed:
send this user-id to the client in it's javascript files.
on the client-side code, make a small adjustment to socket.io handler - for each received message (say, broadcast), you can now check if it's your current user-id and instead of saying 'User #351 says Hi' you can say 'You said Hi on another device' or something like that.
Of course, I'm not socket.io expert, there's could already exist a framework or lib addressing this.
I understand routing (I think), but what's to stop User A from looking at User B's client-side source to discover the socket.io URL specific to each user and then build their own script to start listening for broadcast messages on that particular channel?
You would need to use something to determine who the client is. Once you do that, you could for example use the rooms feature, and only broadcast to the specific room where you put all your authorized users.
To identify the client, you could pass in cookies from the browser in a socket.io request, and compare that to any session data you have stored in Express/Connect/Whatever.