I am working on socket application. and Client emit some event and on the server I handle that event. I want to extract that emitted event from socket object or server. I parsed are socket object but there is nothing which I am looking for. FOR EXAMPLE:
user emit socket.emit('/user/list') on server and handle socket.on('/user/list').. I want to get '/user/list' from socket object. I parsed object but I can't found. If someone know how to get that. I will be appreciated. Thanks in Advance
Related
I am sending message from server by the client.send method and in postman i want to get all messages without adding any event listener like web socket.
In web socket, we do not need to add any event listener,
Similarly, In the socket.io, I want to get all messages without listening to message event like web socket.
server
const socketClients = await this.io.fetchSockets();
socketClients.forEach((client: any) => {
client.send(JSON.stringify(obj))
}
This code sends message to the client, when I am adding an event listener to the postman, getting all messages but I want to get messages without adding event listener like web socket.
I hope you understand my question,
hoping a good answer by you,
Thanks.
I want to emit some data to a room in socket.io.
According to the socket.io docs,
In one place (https://socket.io/docs/rooms-and-namespaces/#Joining-and-leaving) it is said,
io.to('some room').emit('some event');
And in another place (https://socket.io/docs/emit-cheatsheet/) it is said,
socket.to('some room').emit('some event', "description");
I tried both of these but got the error,
uncaught TypeError: io.to is not a function
and
uncaught TypeError: socket.to is not a function
All other socket.io functions i used worked except for this
I included
<script src="/socket.io/socket.io.js"></script>
in the head tag of the html file.
In the client side js file, i incuded
const socket = io.connect("http://localhost:3000/");
Also, I used socket.emit and it works the way it is supposed to.
Please tell me what is wrong with this..
If this Uncaught TypeError is happening on your client side, that's because io.to and socket.to are only server-side functions, and cannot be used on the client side. In the Client API part of the Socket.IO docs, it doesn't specify io.to and socket.to as valid API functions. Here is the client API docs.
And here is a snippet that you can use to emit to Socket.IO rooms:
Server
//Your code...
io.on("connection", socket => {
//Don't forget to do this!
socket.join("some room");
socket.on("some event", data => {
//Do socket.to if you want to emit to all clients
//except sender
socket.to("some room").emit("some event", data);
//Do io.to if you want to emit to all clients
//including sender
io.to("some room").emit("some event", data);
});
});
Client
//Remember to include socket.io.js file!
const socket = io.connect("http://localhost:3000");
socket.on("some event", data => { /* Whatever you want to do */ });
//To emit "some event"
//This will also emit to all clients in the room because of the way the server
//is set up
socket.emit("some event", "description");
If you need an explanation...
So what this does is, basically, since you can't emit to rooms on the client side (you can only emit to server), the client emits to the server, and the server emits the event to the room you want to emit to.
Hope this solves your problem :)
Step1: In the client-side js file, changes instead of io.connect("http://localhost:3000/") use given below line,
let io = require('socket.io').listen(server.listener);
Step2: You need to create a connection in (Both Client & serverSide) For the Testing purpose you can use check connection Establish or not Both End use can use Socket.io tester Chrome Extension.(https://chrome.google.com/webstore/detail/socketio-tester/cgmimdpepcncnjgclhnhghdooepibakm?hl=en)
step3: when a socket connection is Established in Both ends then you emit and listen to data Easily.
One thing when you listen to the data then sends Acknowledgement using Callback Function. I have Received data Successfully.
E.g.`
socket.on('sendMessage',async (chatdata,ack)=>{
ack(chatdata);
socket.to(receiverSocketId).emit('receiveMessage',chatdata);
});
`
yours, emitting a message is correct no need to change this one. But make sure and please check it again your socket connection is Establish successfully or not. another Shortcut way you can debug a code line by line you can easily resolve this problem.
I Hope using this approach you can resolve the Error, and it is help For a Future.
thanks:)
If am emitting from backend and socket id is undefined then will client side get the event that i emitted?
I have also seen that even if the socket id is undefined, client side still gets events but i am not sure how this works.
I am storing socket ids in redis but sometimes i get undefined.
Socket Ids change everytime.
You could decide to save a particular room name in the backend, and use it instead of socket id.
Then fetch it on the frontend and send it to the backend with an emit.
Receive on the server with socket.on , and save it to use it, for example with socket.roomname = roomname
I am very eager to integrate Socket.io to my node.js project, but I have some confusions on how to properly use socket.io. I have been looking through documentations and tutorials, but I have not been able to understand some concepts on how socket.io works.
The scenario I have in mind is the following:
There are multiple clients C1, C2, ..., Cn
Clients emit request to the server R1,...,Rn
Server receives request, does data processing
When data-processing is complete, Server emits response to clients Rs1, .., Rs2
The confusion I have in this scenario is that, when the server has finished data processing it emits the response in the following way:
// server listens for request from client
socket.on('request_from_client', function(data){
// user data and request_type is stored in the data variable
var user = data.user.id
var action = data.action
// server does data processing
do_some_action(..., function(rData){
// when the processing is completed, the response data is emitted as a response_event
// The problem is here, how to make sure that the response data goes to the right client
socket.emit('response_to_client', rData)
})
})
But here I have NOT defined which client I am sending the response to!
How does socket.io handle this ?
How does socket.io make sure that: response Rs1 is sent to C1 ?
What is making sure that: response Rs1 is not sent to C2 ?
I hope I have well explained my doubts.
The instance of the socket object corresponds to a client connection. So every message you emit from that instance is send to the client that opened that socket connection. Remember that upon the connection event you get (through the onDone callback) the socket connection object. This event triggers everytime a client connects to the socket.io server.
If you want to send a message to all clients you can use
io.sockets.emit("message-to-all-clients")
and if you want to send an event to every client apart the one that emits the event
socket.broadcast.emit("message-to-all-other-clients");
I am using net library in node. I want to raise a close event from my code. Is there any way i can do that?
If socket object is stored, I can perform sock.destroy() on it but the client will not be informed about the closing connection, which results in half dropped connection.
Is there any other way to handle this case ?
Emit to that specific socket (client) a custom 'kill_connection' event in order to inform the client about the connection being terminated for whatever reason you decided.
For example using socket.io :
var csid = socket.id; //The socket you are going to destroy
io.to(csid).emit('kill_connection');
Do this before performing the destruction of the socket.
Your client (if a webapp) could look something like:
socket.on("kill_connection", killSession);
function killSession(){
socket.disconnect();
console.log("socket.disconnect");
location.reload();
}
The reload is in case you want a single-page webapp to show the login screen.