Develop Reference

Chrome WebSocket connection closes immediately

I have been trying to setup a wss server using nodejs, and have encountered a problem when trying to connect to it using chrome. The problem still occurs with all extensions disabled and in an incognito window so I've ruled that out as the problem.
When trying to connect using chrome, I get the error:
WebSocket connection to 'wss://www.domain-name.com/' failed:
with no reason given. On the server, socket.on('close') is called immediately with description "Connection dropped by remote peer" The close event has wasClean = false. This error does not occur when connecting from safari and Firefox so I'm not really sure where to look to see what's causing it. It's running on AWS Lightsail, and through an Apache proxy server.
The client code:
var socket = new WebSocket("wss://www.domain-name.com", 'JSON')
socket.onopen = function (event) {
console.log('open');
socket.send('socket opened')};
socket.onclose = function (event) {
console.log(event)};
socket.onmessage = function(message) {
console.log('receiving message from server...')};
And the server code:
const WebSocketServer = require('websocket').server;
app = express()
var server = app.listen(3000, () => {
console.log('Server started');
});
app.use(express.static('public'));
var wsServer = new WebSocketServer({
httpServer: server
});
wsServer.on('request', function(request){
console.log('New connection');
var connection = request.accept(null, request.origin);
connection.send('welcome from server...');
connection.on('message', function(message){
console.log(message)};
connection.on('close', function(reasonCode, description) {
console.log('disconnecting', reasonCode, description);
});
});
I also got the same error before switching to a secure WebSocket server. Any help would be appreciated, I've run out of places to look and ways to try and get more information to help out what the problem is.
EDIT: it seems to work on chrome on my phone, but not on chrome on my friends phone?

The problem was not specifying the protocol when accepting the connection. After about 20 hours working on the same bug and implementing an SSL certificate to get it to work, I changed:
request.accept(null, request.origin);
to:
request.accept('json', request.origin);
For some reason the chrome gives a really unhelpful error message. Microsoft edge the same error occurs, but gives a much more helpful error message so I could work out what was going on.

In my case, this was caused by passing an unused options value as the third parameter to the WebSocket constructor. The options parameter is supported by Node.js's ws module but not by browsers; however, instead of displaying a clean error message, Chrome closed the connection without a good description.

Paho MQTT JS client loses connection to Mosquitto broker when I publish or receive message (error AMQJS0005E)

Bottom line up front: The Paho MQTT client sucessfully connects to my Mosquitto broker, but immediately disconnects when I try to publish a message or when it receives a message from a topic it's subscribed to. I've tried changing Mosquitto's listening port and authentication settings, and using two different versions of Paho MQTT, and I still have the same problem.
Now let's get into detail.
Intro: I'm making a dashboard for some facial recognition devices that communicate through MQTT. I set up a Mosquitto broker and I've had no problems connecting to it and communicating with the devices using the Paho MQTT client for Python (I made a kind of server to sync the device's info to a database). Now I'm making the web interface, so I added a WebSockets listener to my mosquitto.conf and wrote a script using the Paho MQTT library for Javascript to connect to it, subscribe to topic sgdrf/out, send a simple JSON message to topic sgdrf/in to get the list of online devices, and process the response of the Python server once it arrives.
Problem and attempted solutions: I ran the Django server, loaded the web page and opened the JS console to find that the MQTT client successfully connected to the broker but immediately disconnected when it tried to publish the message to topic sgdrf/in. Here's each line of console output with their explanations:
The message produced by the onSuccess function, which indicates that the client successfully connected to the Mosquitto broker:
Conexión exitosa al broker MQTT.
In the onConnected function, I added console.log(uri) to see the URI used by the client to connect to the broker. I got:
ws://localhost:61613/
After printing uri to console, I made the client subscribe to sgdrf/out and then print 'subscribed' to console:
subscribed
Then I call get_online_devices(mqtt_client), a function which creates a simple JSON string and publishes it to the topic sgdrf/in. But first, it prints the strign to the console so that I can check it (just in case):
{"operator":"GetOnlineDevices","messageId":96792535859850080000,"info":{}}
Then, when the publish method is actually executed, is when I get this error (captured by the onConnectionLost function):
Pérdida de conexión con el broker MQTT: AMQJS0005E Internal error. Error Message: message is not defined, Stack trace: No Error Stack Available (código: 5)
I checked the Mosquitto log file and it only says when a new client was connected and then when it was disconnected because of a socket error (each time for every page reload). Tail of /var/log/mosquitto/mosquitto.log:
1614796149: New connection from 127.0.0.1 on port 61612.
1614796149: New client connected from 127.0.0.1 as mqttx_53195902 (p2, c1, k60, u'admin').
1614796182: Socket error on client sgdrf_dashboard_8499, disconnecting.
1614796325: New client connected from ::ffff:127.0.0.1 as sgdrf_dashboard_1597 (p2, c1, k60, u'admin').
1614796325: Socket error on client sgdrf_dashboard_1597, disconnecting.
1614796336: New client connected from ::ffff:127.0.0.1 as sgdrf_dashboard_6565 (p2, c1, k60, u'admin').
1614796336: Socket error on client sgdrf_dashboard_6565, disconnecting.
1614796931: New client connected from ::ffff:127.0.0.1 as sgdrf_dashboard_9773 (p2, c1, k60, u'admin').
1614796931: Socket error on client sgdrf_dashboard_9773, disconnecting.
1614797168: Saving in-memory database to /var/lib/mosquitto/mosquitto.db.
I tried changing the listening port in mosquitto.conf, and enabling and disabling authentication, but it changes nothing. And obviously I've had to restart Mosquito every time I changed the config file. I don't think the problem is Mosquitto.
I have the same problem whether I use Paho MQTT version 1.1.0 or 1.0.3.
As an experiment, I commented out the call to get_online_devices in my Javascript so that it doesn't try to publish anything, reloaded the page and there was no error, as expected. Then, I used MQTTX to send a JSON message to the sgdrf/out topic to which the MQTT JS client is subscribed to, and it immediately disconnected with the same error message.
Code: At the bottom of the page (index.html) I have the following code (the original code has Django template tags to fill in some values, so this is the actual code received by the browser):
<!-- Paho MQTT -->
<script src="/static/js/paho-mqtt-min.js"></script>
<!-- Scripts -->
<script src="/static/js/dashboard.js"></script>
<script>
function get_online_devices(mqtt_client) {
cmd = {
operator: "GetOnlineDevices",
messageId: generate_random_number_n_exp(20),
info: {}
};
payload_string = JSON.stringify(cmd);
console.log(payload_string)
mqtt_client.publish("sgdrf/in", payload_string);
}
function add_device_to_list(device) {
// Omitted for brevity. It's not being used yet.
}
let mqtt_client = make_mqtt_client("localhost", 61613);
let connection_options = make_connection_options(
"admin",
"CENSORED_PASSWORD"
);
mqtt_client.onConnected = function(reconnect, uri) {
console.log(uri)
mqtt_client.subscribe("sgdrf/out");
console.log('subscribed');
get_online_devices(mqtt_client);
};
mqtt_client.onConnectionLost = mqtt_client_on_connection_lost;
mqtt_client.onMessageDelivered = mqtt_client_on_message_delivered;
mqtt_client.onMessageArrived = function (msg) {
// Omitted for brevity. Checks if the payload is a
// JSON object with the right data and calls
// add_device_to_list for each item of a list in it.
};
$(document).ready(function() {
mqtt_client.connect(connection_options);
$("#reload-device-list-btn").click(function() {
get_online_devices(mqtt_client);
});
});
</script>
The dashboard.js files mentioned above just has some functions that I think will be useful for other pages, so I separated them to a file:
// dashboard.js
function generate_random_number_n_exp(n) {
return parseInt(Math.random() * Math.pow(10, n), 10)
}
function make_mqtt_client(host, port) {
let client_id = "sgdrf_dashboard_" + generate_random_number_n_exp(4);
return new Paho.Client(host, port, '/', client_id);
}
function make_connection_options(user, password) {
let connection_options = {
userName: user,
password: password,
onSuccess: mqtt_client_on_success,
onFailure: mqtt_client_on_failure,
};
return connection_options;
}
function mqtt_client_on_success() {
console.log('Conexión exitosa al broker MQTT.');
}
function mqtt_client_on_failure(error) {
console.log(
'Fallo de conexión con el broker MQTT: ' + error.errorMessage
+ ' (código: ' + error.errorCode + ')'
);
}
function mqtt_client_on_connection_lost (error) {
console.log('Pérdida de conexión con el broker MQTT: ' + error.errorMessage
+ ' (código: ' + error.errorCode + ')'
);
}
function mqtt_client_on_message_delivered(msg) {
let topic = message.destinationName;
let payload = message.payloadString;
console.log("Mensaje enviado a " + topic + ": " + payload);
}
function mqtt_client_on_message_arrived(msg) {
let topic = message.destinationName;
let payload = message.payloadString;
console.log("Mensaje recibido de " + topic + ": " + payload);
}
Here are the contents of my mosquitto.conf file:
per_listener_settings true
listener 61612
allow_anonymous false
password_file /home/s8a/Projects/sgdrf/config/pwdfile.txt
listener 61613
protocol websockets
allow_anonymous false
password_file /home/s8a/Projects/sgdrf/config/pwdfile.txt
It just sets up a TCP listener and a WebSockets listener, both disallow anonymous connections, and authenticate using a pwdfile. As I said before, I have enabled and disabled anonymous connections, and changed the port number to 9001 and back to 61613, and I still have the same error.
Conclusion: I don't know what to do and this project's deadline is next week.

I feel kinda stupid, because it was really a trivial typing mistake. The problem is that the onMessageDelivered and onMessageArrived functions have msg as argument, but I wrote messagein the function body for some reason. That's what the "message is not defined" error meant, message is literally not defined. Anyway I fixed that and now it sends and receives messages without problems.
...
More detailed story: What was not trivial is how I figured it out.
I decided to get my hands dirty and opened the non-minified version of paho-mqtt.js. I looked for "Invalid error" and found where the error constant is defined, and two places where it's used in a catch block. In both catch blocks I noticed that there was a ternary operator checking if (error.hasOwnProperty("stack") == "undefined") but the true and false clauses were inverted, which is why I was getting "No Error Stack Available".
So I inverted the clauses, and indeed I got a stack trace in the console (maybe I should file a bug report to the Paho dev team when I can). The stack trace had my mqtt_client_on_message_delivered function right at the top, so I read it again and suddenly everything made sense. Then I felt stupid for wasting an afternoon on this.

binaryjs client crashes when server restarts

I'm using binaryjs to implement a video transfer program between node.js server and node-webkit client.The client stays connected,once a video is uploaded,the client starts downloading it.
It works fine generally,the client does get the videos.But the client throws an error and crashes when the server restarts or crashes. I have been listening the BinaryClient 'error' & 'close' event,however it doesnot works.
I guess maybe i'd listen 'error' event from something else.What to do to fix the problem?Anyone can help?
Thanks a lot!
app.js:
var BinaryServer = require('binaryjs').BinaryServer;
var server = http.createServer(app).listen(3000);
var binaryServer = new BinaryServer({ server: server, path: '/binary' });
binaryServer.on('connection', function (client) {
// client on stream
// client on close
// client on error
});
// binaryServer on error
client:
var BinaryClient = require('binaryjs').BinaryClient;
var binaryClient = new BinaryClient('ws://127.0.0.1:3000/binary');
binaryClient.on('open', function () {
// binaryClient.createStream( ... )
});
// binaryClient on stream
// binaryClient on close
// binaryClient on error
error:
Uncaught node.js Error
Error: read ECONNRESET
at exports._errnoException (util.js:742:11)
at TCP.onread (net.js:541:26)

How to know if a connection error occurred when using thrift from a javascript client?

I'm running the following thrift javascript client code. If the server is down, I don't get any error in the callback - just console log message.
How do I know if there're connection issues if the callback isn't invoked?
Javascript thrift client code:
var transport = new Thrift.Transport("/api/thrift/");
var protocol = new Thrift.Protocol(transport);
var client = new ApiClient(protocol);
client.doSomething(function (result) {
// Never invoked if the server is down.
});
Console log message:
POST http://localhost:81/api/thrift/ net::ERR_CONNECTION_REFUSED

Cross room communication puzzle

I try to send some message across rooms. I have:
server.js
var io = require('socket.io').listen(8081);
var chat = io
.of('/chat')
.on('connection', function (socket) {
socket.on('chatTestEmit1', function(d) {
console.log('>> chatTestEmit1 >> '+JSON.stringify(d));
console.log(io.sockets.manager.rooms);
socket.to('/news').emit('newsTestEmit1', d);
});
});
var news = io
.of('/news')
.on('connection', function (socket) {
socket.on('checkAlive', function(d) {
console.log('>> checkAlive >> '+JSON.stringify(d));
});
socket.on('newsTestEmit1', function(d){
console.log('>> newsTestEmit1 >> '+JSON.stringify(d));
});
});
client.html
<script src="http://localhost:8081/socket.io/socket.io.js"></script>
<script>
var chat = io.connect('http://localhost:8081/chat')
, news = io.connect('http://localhost:8081/news');
chat.on('connect', function () {
chat.emit('chatTestEmit1',{msg:'This is the message from client.'});
});
news.on('connect', function(){
news.emit('checkAlive',{msg:'News is alive'});
});
</script>
The log looks like this:
info - socket.io started
debug - client authorized
info - handshake authorized 74858017692628057
debug - setting request GET /socket.io/1/websocket/74858017692628057
debug - set heartbeat interval for client 74858017692628057
debug - client authorized for
debug - websocket writing 1::
debug - client authorized for /chat
debug - websocket writing 1::/chat
debug - client authorized for /news
debug - websocket writing 1::/news
>> chatTestEmit1 >> {"msg":"This is the message from client."}
{ '': [ '74858017692628057' ],
'/chat': [ '74858017692628057' ],
'/news': [ '74858017692628057' ] }
debug - websocket writing 5::/chat:{"name":"newsTestEmit1","args":[{"msg":"This is the message from client."}]}
>> checkAlive >> {"msg":"News is alive"}
debug - emitting heartbeat for client 74858017692628057
debug - websocket writing 2::
debug - set heartbeat timeout for client 74858017692628057
debug - got heartbeat packet
debug - cleared heartbeat timeout for client 74858017692628057
debug - set heartbeat interval for client 74858017692628057
debug - emitting heartbeat for client 74858017692628057
If this code worked correctly, it should have logged as below:
>> newsTestEmit1 >> {"msg":"This is the message from client."}
appeared in the log. Note that I also tried:
io.sockets.in('/news').emit('newsTestEmit1', d);
io.sockets.in('news').emit('newsTestEmit1', d);
io.of('/news').emit('newsTestEmit1', d);
None of them works. Do I miss something?
Thanks.

I did not look through all of your code, but the general idea is that you want to emit an event + the data from the client-side when a message is sent, then set an event on the server-side to broadcast when a happens. Some psuedo server-side code below:
io.sockets.on('connection', function (socket) {
console.log('Socket connection established.');
socket.on('message event', function(data){
socket.broadcast.emit('global chat update', data);}
);
});
On the client side you want 2 bits of code:
1) When a chat event happens, something like:
socket.emit('message event', data)
2) Something to display the newest chat when there is a global chat update.
socket.on('global chat update', function(data) { // your script to update chat data here };