How to broadcast a message among all the connected clients in socket.io?
I am using mrniko/netty-cosket.io server with with java (play/eclipse) on server side and socket.io.js 0.9 on client side. Both client & server working fine (i.e. sending and receiving messages). To keep the records of the connected clients , I am using hashMaps and to send a message to all connected users I am iterating the hashmap and sending messages one by one. just wanna know is there any better way to send messages to all connected clients at once?
Any help will be highly appreciated.
Here is an example in case of mrniko/netty-socket.io usage:
Configuration config = new Configuration();
config.setHostname("localhost");
config.setPort(9092);
SocketIOServer server = new SocketIOServer(config);
BroadcastOperations bo = server.getBroadcastOperations();
// every method will broadcast messages to all server clients
bo.sendJsonObject(...)
server.start();
...
you can use the following code:
//broadcasts to all clients connected
io.sockets.emit('function', {foo:bar});
//broadcasts to all clients connected, except the sender
io.sockets.on('connection', function (socket) {
socket.on('message', function(data) {
socket.broadcast.emit('function', {foo:bar});
}
}
Related
I'm using Apache Artemis ActiveMQ 2.6.3 as an MQTT broker embedded in a Spring 5 application:
#Bean(initMethod = "start", destroyMethod = "stop")
fun embeddedActiveMQ(securityManager: ActiveMQJAASSecurityManager) =
EmbeddedActiveMQ().apply {
setConfiguration(getEmbeddedActiveMQConfiguration())
setConfigResourcePath("activemq-broker.xml")
setSecurityManager(securityManager)
}
private fun getEmbeddedActiveMQConfiguration() =
ConfigurationImpl().apply {
addAcceptorConfiguration("netty", DefaultConnectionProperties.DEFAULT_BROKER_URL)
addAcceptorConfiguration("mqtt", "tcp://$host:$mqttPort?protocols=MQTT")
name = brokerName
bindingsDirectory = "$dataDir${File.separator}bindings"
journalDirectory = "$dataDir${File.separator}journal"
pagingDirectory = "$dataDir${File.separator}paging"
largeMessagesDirectory = "$dataDir${File.separator}largemessages"
isPersistenceEnabled = persistence
connectionTTLOverride = 60000
}
Although I'm setting the connection TTL to 60 seconds in the above Kotlin code as suggested in the documentation and the client disconnected and terminated an hour ago, the log shows the following entries:
2020-06-22 10:57:03,890 [Thread-29 (ActiveMQ-server-org.apache.activemq.artemis.core.server.impl.ActiveMQServerImpl$5#ade4717)] DEBUG o.a.a.a.core.server.impl.QueueImpl - Scanning for expires on client1.some-topic
2020-06-22 10:58:03,889 [Thread-35 (ActiveMQ-server-org.apache.activemq.artemis.core.server.impl.ActiveMQServerImpl$5#ade4717)] DEBUG o.a.a.a.core.server.impl.QueueImpl - Scanning for expires on client1.some-topic
Based on these log entries, I'm afraid that "dead" connection resources are never cleaned up by the server.
What should I do to actually remove the "dead" connections from the server to avoid leaking resources?
The broker will often create resources like addresses, queues, etc. to deal with clients. In the case of MQTT clients the broker will create queues which essentially represent the client's subscriptions.
In this particular case a queue named client1.some-topic has been created for an MQTT subscription and the broker is scanning that queue for expired messages. At this point it looks like the broker is working as designed.
When a client disconnects without unsubscribing what the broker does with the subscription depends on whether the client used a clean session or not.
If the client used a clean session then the broker will delete the subscription queue when the client disconnects (even in the event of a failure).
Otherwise the broker is obliged to hold on to the subscription queue and route messages to it. If the client never reconnects to unsubscribe then the subscription may fill up with lots of messages and trigger the broker's paging mode and eventually even limit message production altogether. In this case the client can either reconnect and unsubscribe or the subscription queue can be removed administratively.
I require to send get requests/ receive responses to several snmp agents from a single client/manager process.
I have implemented client/agent based on below urls:
http://www.jitendrazaa.com/blog/java/snmp/create-snmp-client-in-java-using-snmp4j/ http://www.jitendrazaa.com/blog/java/snmp/creating-snmp-agent-server-in-java-using-snmp4j/
In order to send a request to an agent, the following is carried out for each server:
TransportMapping transport = new DefaultUdpTransportMapping();
snmp = new Snmp(transport);
transport.listen();
...
pdu.setType(PDU.GET);
// communityTarget contains server target address.
ResponseEvent event = snmp.send(pdu, communityTarget, null);
In order to receive responses from the servers, do I require to carry out a separate transport.listen() for each server? or create
a new TransportMapping and Snmp object for each server?
I don't understand how the client process can know which server returned the response? ...since
each time transport.listen() is called, the listening port address (transport.getListenAddress()) is the same.
and 1 extra udp port is listed (netstat).
I am intending to poll each server from a different background thread (in order that the polling interval can be configured).
Thank you
You should use the same transport mapping.
From the example you provided, it seems that you are using the synchronous API.
The response is just from the agent you sent the request too.
In any case, you can get the peer (agent) address from ResponseEvent.getPeerAddress
http://www.snmp4j.org/doc/org/snmp4j/event/ResponseEvent.html#getPeerAddress()
I have an application that connects to a web page that sends and receives text strings over a websocket on port 1234. I do not have access to the front end code, so I cannot change the HTML front end code.
I created an autobahn server with a class derived from WebSocketServer protocol that communicates with the web page over port 1234. This works and I am able to send and receive text to the front end.
However, I need to process incoming data and would like to publish the received data to a crossbar.io container through the router on port 8080 (or any other port). The port to the web browser is fixed at 1234.
It there a way for me to "plug in " the autobahn websocket server into the crossbar router or is there an alternative way to create a websocket server that will allow me to to send and receive the text on port 1234 and at the same time participate in pub/sub and RPC with the crossbar router?
I am assuming you are using Python. If you are not, the answer should still be the same, but depending on the language/library and its implementation the answer can change.
From what you are saying, it does not sound like you really need a "plug in". Crossbar does have these under the description of router components. But unless you really need to attach a Python instance directly to the router either for performance or otherwise, I would recommend keeping your application off the router. It would work perfectly fine as a stand alone instance especially if it is on the same machine where the WAMP router is located where the packets would only require to communicate over loopback (which is VERY fast).
Given that you are using Python:
You can use your WebSocketServer and a WampApplicationServer together. The little hiccup you might run into is starting them up properly. In either scenario Python2.x with twisted or Python3.4 with Asyncio you can only start the reactor/event loop once or an error will ensue. (Both Twisted and Asyncio have the same basic concept) In Asyncio you will get RuntimeError: Event loop is running. if you attempt to start the event loop twice. Twisted has a similar error. Using the ApplicationRunner in twisted, there is an option (second argument in run) not to start up the reactor which you can use after the reactor is already running. In Asyncio, there is no such option, the only way I found out how to do it is to inherit the Application runner and overwrite the run method to start the session to be started as a task. Also, be warned that threads do not cooperate with either event loop unless properly wrapped.
Once you have the two connections set up in one instance you can do whatever you want with the data.
Thanks for the idea, and the problems you mention are exactly what I encountered. I did find a solution however, and thanks to the flexibility of crossbar, created a JavaScript guest that allows me to do exactly what I need. Here is the code:
// crossbar setup
var autobahn = require('autobahn');
var connection = new autobahn.Connection({
url: 'ws://127.0.0.1:8080/ws',
realm: 'realm1'
}
);
// Websocket to Scratch setup
// pull in the required node packages and assign variables for the entities
var WebSocketServer = require('websocket').server;
var http = require('http');
var ipPort = 1234; // ip port number for Scratch to use
// this connection is a crossbar connection
connection.onopen = function (session) {
// create an http server that will be used to contain a WebSocket server
var server = http.createServer(function (request, response) {
// We are not processing any HTTP, so this is an empty function. 'server' is a wrapper for the
// WebSocketServer we are going to create below.
});
// Create an IP listener using the http server
server.listen(ipPort, function () {
console.log('Webserver created and listening on port ' + ipPort);
});
// create the WebSocket Server and associate it with the httpServer
var wsServer = new WebSocketServer({
httpServer: server
});
// WebSocket server has been activated and a 'request' message has been received from client websocket
wsServer.on('request', function (request) {
// accept a connection request from Xi4S
//myconnection is the WS connection to Scratch
myconnection = request.accept(null, request.origin); // The server is now 'online'
// Process Xi4S messages
myconnection.on('message', function (message) {
console.log('message received: ' + message.utf8Data);
session.publish('com.serial.data', [message.utf8Data]);
// Process each message type received
myconnection.on('close', function (myconnection) {
console.log('Client closed connection');
boardReset();
});
});
});
};
connection.open();
I have two WebSocket servers that can communicate wonderfully with a client. They are on two separate machines, implemented in Java and running inside WildFly8 webservers. What I need them to do now is communicate with each other. That means: client sends message to server 1, server 1 sends message to server 2, receives the reply and sends it back to client.
The servers run on different apps in OpenShift and I need them to use websockets. Or some other type of communication, but I haven't managed to find anything that actually works so far (RMI or normal socket connections won't work).
What I basically tried to do is use the same code from the client within the onMessage method of the first server. Something like this:
#OnMessage
public void message(Session session, String msg){
...
WebSocketContainer container = ContainerProvider.getWebSocketContainer();
Session NewSession = container.connectToServer(Client.class, URI.create(URL));
NewSession.getBasicRemote().sendText("Routed :" + input);
...
}
However, the server does not connect to the other server and I don't know why.
Any suggestions?
Thank you!
Put connectToServer inside a try {} catch, you might get an error. Log it.
I'm struggling to do exactly the same things (2 websocket servers, Wildfly 8), and I get a permission denied error. See my post here:
https://stackoverflow.com/questions/30966757/java-server-to-server-communication-with-websockets-permission-denied
Is there any way to disconnect a client with SocketIO, and literally close the connection? So if someone is connected to my server, and I want to close the connection between them and my server, how would I go about doing that?
Edit: This is now possible
You can now simply call socket.disconnect() on the server side.
My original answer:
This is not possible yet.
If you need it as well, vote/comment on this issue.
socket.disconnect() can be used only on the client side, not on the server side.
Client.emit('disconnect') triggers the disconnection event on the server, but does not effectively disconnect the client. The client is not aware of the disconnection.
So the question remain : how to force a client to disconnect from server side ?
Any reason why you can't have the server emit a message to the client that makes it call the disconnect function?
On client:
socket.emit('forceDisconnect');
On Server:
socket.on('forceDisconnect', function(){
socket.disconnect();
});
Checking this morning it appears it is now:
socket.close()
https://socket.io/docs/client-api/#socket-close
For those who found this on google - there is a solution for this right now:
Socket.disconnect() kicks the client (server-side). No chance for the client to stay connected :)
Assuming your socket's named socket, use:
socket.disconnect()
This didn't work for me:
`socket.disconnect()`
This did work for me:
socket.disconnect(true)
Handing over true will close the underlaying connection to the client and not just the namespace the client is connected to Socket IO Documentation.
An example use case: Client did connect to web socket server with invalid access token (access token handed over to web socket server with connection params). Web socket server notifies the client that it is going to close the connection, because of his invalid access token:
// (1) the server code emits
socket.emit('invalidAccessToken', function(data) {
console.log(data); // (4) server receives 'invalidAccessTokenEmitReceived' from client
socket.disconnect(true); // (5) force disconnect client
});
// (2) the client code listens to event
// client.on('invalidAccessToken', (name, fn) => {
// // (3) the client ack emits to server
// fn('invalidAccessTokenEmitReceived');
// });
In my case I wanted to tear down the underlying connection in which case I had to call socket.disconnect(true) as you can see is needed from the source here
client._onDisconnect() should work
I'm using client.emit('disconnect') + client.removeAllListeners() for connected client for ignore all events after disconnect
Socket.io uses the EventEmitter pattern to disconnect/connect/check heartbeats so you could do. Client.emit('disconnect');
I am using on the client side socket.disconnect();
client.emit('disconnect') didnt work for me
You can do socket = undefined in erase which socket you have connected. So when want to connected do socket(url)
So it will look like this
const socketClient = require('socket.io-client');
let socket;
// Connect to server
socket = socketClient(url)
// When want to disconnect
socket = undefined;
I have using the socket client on React Native app, when I called socketIOClient.disconnect() this disconnects from the server but when I connect to the socket again the previous events were connected again, and the below code works for me by removing all existing events and disconnecting socket conneciton.
socketIOClient.removeAllListeners();
socketIOClient.disconnect(true);
To disconnect socket forcefully from server side
socket.disconnect(true)
OR
To disconnect socket by client side event
On client:
socket.emit('forceDisconnect');
On Server:
socket.on('forceDisconnect', function(){
socket.disconnect(true);
});
You can call socket.disconnect() on both the client and server.
Add new socket connections to an array and then when you want to close all - loop through them and disconnect. (server side)
var socketlist = [];
io.sockets.on('connection', function (socket) {
socketlist.push(socket);
//...other code for connection here..
});
//close remote sockets
socketlist.forEach(function(socket) {
socket.disconnect();
});
use :
socket.Disconnect() //ok
do not use :
socket.disconnect()