I am sending a stomp message over a Sock.JS client. When I disconnect the server I would like a warning message to show up on the client. To do this I have implemented a server side heartbeat
stompClient = Stomp.over(socket);
stompClient.heartbeat.outgoing = 20000;
stompClient.heartbeat.incoming = 20000;
stompClient.connect({}, function(frame) {
...
}
In the Chrome developer console I see the message
POST http://localhost:8080/hello/800/8n_btbxb/xhr_streaming net::ERR_CONNECTION_RESET sockjs-0.3.min.js:27
Whoops! Lost connection to undefined
How can I capture this error message?
As pointed out by muttonUp stomp.js from https://github.com/jmesnil/stomp-websocket/ will overwrite the onclose handler. On the other hand it provides the option to pass an error-callback on connect:
stompClient.connect({}, function(frame) {
...
}, function(message) {
// check message for disconnect
});
Since you will get several kinds of errors delivered to your callback, you have to check the message it it was indeed the "Whoops! [...]" which indicates a connection loss.
Oops just figured it out I will delete in a bit if it doesn't help others. I needed to use SockJS client instead of the Stomp one...
var socket = new SockJS('/hello');
...
socket.onclose = function() {
console.log('close');
stompClient.disconnect();
setConnected();
};
Related
I have an Electron app which tries to connect to a device over a web socket. The connection is encrypted (i.e. wss) but the SSL certificate is self signed and thus, untrusted.
Connecting inside Chrome is ok and it works. However inside Electron I run into problems. Without putting any certificate-error handlers on the BrowserWindow or on the app I receive the following error in the console output:
WebSocket connection to 'wss://some_ip:50443/' failed: Error in connection establishment: net::ERR_CERT_AUTHORITY_INVALID
Then shortly after:
User is closing WAMP connection.... unreachable
In my code, to make the connection I run the following.
const connection = new autobahn.Connection({
realm: 'some_realm',
url: 'wss://some_ip:50443'
});
connection.onopen = (session, details) => {
console.log('* User is opening WAMP connection....', session, details);
};
connection.onclose = (reason, details) => {
console.log('* User is closing WAMP connection....', reason, details);
return true;
};
connection.open();
// alternatively, this also displays the same error
const socket = new WebSocket(`wss://some_ip:50443`);
socket.onopen = function (event) {
console.log(event);
};
socket.onclose = function (event) {
console.log(event);
};
NOTE: Autobahn is a Websocket library for connecting using the WAMP protocol to a socket server of some sort. (in my case, the device) The underlying protocol is wss. Underneath the code above, a native JS new WebSocket() is being called. In other words:
As I mentioned, I've tested this code in the browser window and it works. I've also built a smaller application to try and isolate the issue. Still no luck.
I have tried adding the following code to my main.js process script:
app.commandLine.appendSwitch('ignore-certificate-errors');
and
win.webContents.on('certificate-error', (event, url, error, certificate, callback) => {
// On certificate error we disable default behaviour (stop loading the page)
// and we then say "it is all fine - true" to the callback
event.preventDefault();
callback(true);
});
and
app.on('certificate-error', (event, webContents, link, error, certificate, callback) => {
// On certificate error we disable default behaviour (stop loading the page)
// and we then say "it is all fine - true" to the callback
event.preventDefault();
callback(true);
});
This changed the error to:
WebSocket connection to 'wss://some_ip:50443/' failed: WebSocket opening handshake was canceled
My understanding is that the 'certificate-error' handlers above should escape any SSL certificate errors and allow the application to proceed. However, they're not.
I've also tried adding the following to main.js:
win = new BrowserWindow({
webPreferences: {
nodeIntegration: true,
webSecurity: false
}
});
process.env.ELECTRON_DISABLE_SECURITY_WARNINGS = '1';
process.env.NODE_TLS_REJECT_UNAUTHORIZED = '0';
With Election, how do I properly deal with a certificate from an untrusted authority? i.e. a self signed cert.
Any help would be much appreciated.
I had the same problem , all i added was your line:
app.commandLine.appendSwitch('ignore-certificate-errors');
I use socket.io, but i think its the same principal.
I do however connect to the https protocol and not wss directly.
This is what my connection looks like on the page:
socket = io.connect(
'https://yoursocketserver:yourport', {
'socketpath',
secure: false,
transports: ['websocket']
});
That seems to have done the trick.
Thank you for the help :) i hope this answer helps you too.
Do we always have to use socket.emit() inside a socket.on() like that:
io.sockets.on('connection', function (socket) {
console.log('User connected !');
retrieveDictionnary((dictionnary) =>{
socket.emit('dictionnarySend', dictionnary);
}
}
I want to create on my client side a function which ask information to the server when I click on a button:
translateServer(parameter, control){
this.socket.emit('translate', [parameter,control]);
}
But it seems that it's not working, the server never receive this message.
Thank you !
The pattern you are using above is the recommended way of interacting with a socket (ie acquiring a socket instance when the 'connection' event fires, and then calling emit() from that socket instance, etc).
If I understand your client-side requirements correctly, you are wanting to send data to the server via web sockets - are you sure the socket that you have established a web socket connection between the client and server?
For instance, if you add the following to your client-side code, you should see a success message in your console:
const socket = io.connect('YOUR SERVER ADDRESS');
socket.on('connect', () => {
console.log('connected to server!');
// [UPDATE]
// This assumes you have a <button> element on your page. When
// clicked, a message will be sent to the server via sockets
document.querySelector('button').addEventListener('click', (event) => {
// Prevent button click reloading page
event.preventDefault();
// Send message to server via socket
socket.emit('MESSAGE_ID', 'test message from client' + new Date());
});
});
Update
This shows your original server code, expanded with the detail needed to receive and print data sent from client via sockets:
io.sockets.on('connection', function (socket) {
console.log('User connected !');
// Register a server handler for any messages from client on MESSAGE_ID channel
socket.on('MESSAGE_ID', (message) => {
// Print the message received from client in console
console.log('message from client', message);
})
retrieveDictionnary((dictionnary) =>{
socket.emit('dictionnarySend', dictionnary);
}
}
In Flutter, I wanna listen to websocket disconnect event, how to achieve that?
The websocket connect will be drop when app goes to background, I still not found a method to let it continuesly running in background (does anyone have solution?), So I have to detect if a websocket connect is lost or something, so that I can re-connect when lost connection.
Pls help if anyone knows how to achieve that.
You can find out if websocket is closed by implementing onDone callback. See the example below:
_channel = IOWebSocketChannel.connect(
'ws://yourserver.com:port',
);
///
/// Start listening to new notifications / messages
///
_channel.stream.listen(
(dynamic message) {
debugPrint('message $message');
},
onDone: () {
debugPrint('ws channel closed');
},
onError: (error) {
debugPrint('ws error $error');
},
);
Hope that helps.
If your server closes the connection just use pinginterval like this
ws.pingInterval = const Duration(seconds: 5);
onDone should be called.
basic ping pong is enough.
Other answers around SO and the web suggest that you can't just keep sockets open in the background (which seems reasonable, you'd be keeping open network connections that may affect battery life). Depending on your use case, you might be better looking at Push Notifications or something that checks on a schedule.
How to keep iphone ios xmpp connection alive while in the background?
Websocket paused when android app goes to background
https://www.quora.com/How-do-I-keep-Socket-IO-running-in-the-background-on-iOS
WebSocketChannel channel = WebSocketChannel.connect(uri );
Stream stream = channel.stream;
stream.listen((event) {
print('Event from Stream: $event');
},onError: (e){
Future.delayed(Duration(seconds: 10)).then((value) {
connectAndListen();
},);
},
onDone: (() {
Future.delayed(Duration(seconds: 10)).then((value) {
connectAndListen();
},);
})
);
I recommend you to use this multiplatform websocket package https://pub.dev/packages/websocket_universal , there you can even track all WS events happening (and even built-in ping measurment if you need any):
import 'package:websocket_universal/websocket_universal.dart';
/// Example works with Postman Echo server
void main() async {
/// Postman echo ws server (you can use your own server URI)
/// 'wss://ws.postman-echo.com/raw'
/// For local server it could look like 'ws://127.0.0.1:42627/websocket'
const websocketConnectionUri = 'wss://ws.postman-echo.com/raw';
const textMessageToServer = 'Hello server!';
const connectionOptions = SocketConnectionOptions(
pingIntervalMs: 3000, // send Ping message every 3000 ms
timeoutConnectionMs: 4000, // connection fail timeout after 4000 ms
/// see ping/pong messages in [logEventStream] stream
skipPingMessages: false,
/// Set this attribute to `true` if do not need any ping/pong
/// messages and ping measurement. Default is `false`
pingRestrictionForce: false,
);
/// Example with simple text messages exchanges with server
/// (not recommended for applications)
/// [<String, String>] generic types mean that we receive [String] messages
/// after deserialization and send [String] messages to server.
final IMessageProcessor<String, String> textSocketProcessor =
SocketSimpleTextProcessor();
final textSocketHandler = IWebSocketHandler<String, String>.createClient(
websocketConnectionUri, // Postman echo ws server
textSocketProcessor,
connectionOptions: connectionOptions,
);
// Listening to webSocket status changes
textSocketHandler.socketHandlerStateStream.listen((stateEvent) {
// ignore: avoid_print
print('> status changed to ${stateEvent.status}');
});
// Listening to server responses:
textSocketHandler.incomingMessagesStream.listen((inMsg) {
// ignore: avoid_print
print('> webSocket got text message from server: "$inMsg" '
'[ping: ${textSocketHandler.pingDelayMs}]');
});
// Listening to debug events inside webSocket
textSocketHandler.logEventStream.listen((debugEvent) {
// ignore: avoid_print
print('> debug event: ${debugEvent.socketLogEventType}'
' [ping=${debugEvent.pingMs} ms]. Debug message=${debugEvent.message}');
});
// Listening to outgoing messages:
textSocketHandler.outgoingMessagesStream.listen((inMsg) {
// ignore: avoid_print
print('> webSocket sent text message to server: "$inMsg" '
'[ping: ${textSocketHandler.pingDelayMs}]');
});
// Connecting to server:
final isTextSocketConnected = await textSocketHandler.connect();
if (!isTextSocketConnected) {
// ignore: avoid_print
print('Connection to [$websocketConnectionUri] failed for some reason!');
return;
}
textSocketHandler.sendMessage(textMessageToServer);
await Future<void>.delayed(const Duration(seconds: 30));
// Disconnecting from server:
await textSocketHandler.disconnect('manual disconnect');
// Disposing webSocket:
textSocketHandler.close();
}
server
var io = require('socket.io'),
UUID = require('node-uuid'),
gameport = 3000;
var db = {
waiting_clients: []
};
var logic = {
};
var sio = io.listen(gameport);
sio.sockets.on('connection', function(socket){
var client = {
id: UUID()
};
socket.emit('news', client);
console.log(client.id);
db.waiting_clients.push(client);
});
test client:
var net = require('net');
var client = net.connect({port: 3000},
function(e) { //'connect' listener
console.log('client connected');
client.end();
});
in test client console, it show "client connected". But there are no output in server console
You must use a socket.io client to connect to a socket.io server. Your code shows that you are trying to make a generic TCP connection to a socket.io server. That will not work. The lowest level connection will be established, but then the initial protocol handshake will fail and the socket.io server will drop the connection and you will never get the connection event.
Socket.io has its own connection scheme built on top of webSocket which is built on top of HTTP which is built on top of TCP.
So, to connect to a socket.io server, you must use a socket.io client that runs both the socket.io and webSocket protocol, not a plain TCP socket.
I want to use sockets in my web app. I don't want to use socket.io library on client-side. It's OK for server-side though. Can I do this?
Now with socket.io on server and pure websocket on client I have destroying non-socket.io upgrade error. I've googled that it means that I have to use socket.io-client library on client-side. Is there any way to avoid that? I don't want client to be tight with this library and use pure html5 websocket instead.
If it's not possible what should I use for server to connect with pure html5 websockets?
If someone is curious here is my server code (coffeescript file)
# Require HTTP module (to start server) and Socket.IO
http = require 'http'
io = require 'socket.io'
# Start the server at port 8080
server = http.createServer (req, res) ->
# Send HTML headers and message
res.writeHead 200, { 'Content-Type': 'text/html' }
res.end "<h1>Hello from server!</h1>"
server.listen 8080
# Create a Socket.IO instance, passing it our server
socket = io.listen server
# Add a connect listener
socket.on 'connection', (client) ->
# Create periodical which ends a message to the client every 5 seconds
interval = setInterval ->
client.send "This is a message from the server! #{new Date().getTime()}"
, 5000
# Success! Now listen to messages to be received
client.on 'message', (event) ->
console.log 'Received message from client!', event
client.on 'disconnect', ->
clearInterval interval
console.log 'Server has disconnected'
And here is a client-side
<script>
// Create a socket instance
socket = new WebSocket('ws://myservername:8080');
// Open the socket
socket.onopen = function (event) {
console.log('Socket opened on client side', event);
// Listen for messages
socket.onmessage = function (event) {
console.log('Client received a message', event);
};
// Listen for socket closes
socket.onclose = function (event) {
console.log('Client notified socket has closed', event);
};
};
</script>
I've found this library, seems OK for my needs https://npmjs.org/package/ws