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.

Connection to socket gets error "WebSocket opening handshake timed out" using Javascript and C#

About 4 hours of research...here we go.
I have a C# program that sends and listens for anything coming in a specific Socket. Using the sockets, C# can send stuff to it and can receive from it just fine. Now, going to my JavaScript file, I'm using the WebSocket interface to communicate with C#, but doesn't work (usually times out after a couple of minutes). When the Socket is online, the JavaScript code will take up to about 4 minutes then throw an error saying "WebSocket opening handshake timed out". The thing is I know that it can find because, when the port of the ip doesn't exist the JavaScript file throws an error in the next couple seconds.
Things I've done:
Turn off all firewalls, use both ws and wss at the beginning of the ip and port (ex: wss://xxx.xxx.x.xx:11111), change the port, change the ip to a valid ip still reachable, research for 4 hours.
C#:
IPHostEntry ipHost = Dns.GetHostEntry(Dns.GetHostName());
IPAddress ipAddr = IPAddress.Parse("ip");
IPEndPoint localEndPoint = new IPEndPoint(ipAddr, 11111);
Socket listener = new Socket(ipAddr.AddressFamily, SocketType.Stream, ProtocolType.Tcp);
try
{
listener.Bind(localEndPoint);
listener.Listen(10);
while (true)
{
Console.WriteLine("Waiting connection...");
Socket clientSocket = listener.Accept();
byte[] bytes = new Byte[1024];
string data = null;
while (true)
{
int numByte = clientSocket.Receive(bytes);
data += Encoding.ASCII.GetString(bytes, 0, numByte);
if (data.IndexOf("<EOF>") > -1)
{
break;
}
}
Console.WriteLine("Text received -> {0} ", data);
byte[] message = Encoding.ASCII.GetBytes("Test Server");
clientSocket.Send(message);
clientSocket.Shutdown(SocketShutdown.Both);
clientSocket.Close();
}
}
catch (Exception e)
{
Console.WriteLine(e.ToString());
}
JavaScript:
socket = new WebSocket("wss://ip:11111");
socket.onopen = function()
{
alert("Connected!");
}
socket.onerror = function()
{
alert("Connection Failed");
}
The ip is local
Long story short, C# can communicate with itself and JavaScript can find it but can't communicate with it.

Properly complete a handshake. (Or use a library / connection type that does.)
The WebSocket protocol (as original defined in RFC6455 - The WebSocket Protocol) does not open a plain unrestricted socket, in part for security reasons.
Since the handshake is not complete, the client WS request will timeout as the HTTP “Upgrade” response is never received. Until the handshake is complete, the WS will not be active over the underlying TCP connection.
Initiating a WebSocket connection (“the handshake”) is defined in section 4 of the RFC. It is also discussed in How JavaScript works: Deep dive into WebSockets and HTTP/2 with SSE + how to pick the right path.
The client establishes a WebSocket connection through a process known as the WebSocket handshake. This process starts with the client sending a regular HTTP request to the server. An Upgrade header is included in this request which informs the server that the client wishes to establish a WebSocket connection.
..
Now that [after] the handshake is complete the initial HTTP connection is replaced by a WebSocket connection that uses the same underlying TCP/IP connection. At this point, either party can start sending data.

Unable to connect to Mosquitto over Websocket

I am unable to connect to my local Mosquitto 1.4.10 broker from a JavaScript client over a Websocket.
The same JavaScript client is successfully connecting to the public broker at test.mosquitto.org on port 8080 over a Websocket.
The MQTT protocol connection on port 1883 is working fine, which I tested using mosquitto_pub and mosquitto_sub.
My broker is set up within a VirtualBox running Ubuntu 14.04.
I have libwebsockets installed on the same virtual machine.
My local broker was compiled with WITH_WEBSOCKETS:=yes in the config.mk file
I am loading the JavaScript client web page from the same virtual machine from a Firefox browser and seeing the following error message in the browser console:
Firefox can't establish a connection to the server at
ws://localhost:8080/mqtt
Your suggestions on fixing this will be greatly appreciated.
Thanks.
Here is my Mosquitto .conf file:
port 1883
listener 8080
protocol websockets
log_type all
websockets_log_level 1023
connection_messages true
Here is the Mosquitto server's log (with websockets logging level set to 1023, and verbose logging turned on - no messages appear when I load the JavaScript web page):
1481381105: mosquitto version 1.4.10 (build date 2016-12-10
18:47:37+0530) starting
1481381105: Config loaded from /etc/mosquitto/mosquitto.conf.
1481381105: Opening websockets listen socket on port 8080.
1481381105: Initial logging level 1023
1481381105: Libwebsockets version: 2.1.0 manavkumarm#manav-alljoyn
1481381105: IPV6 not compiled in
1481381105: libev support not compiled in
1481381105: libuv support not compiled in
1481381105: Threads: 1 each 1024 fds
1481381105: mem: platform fd map: 4096 bytes
1481381105: Compiled with OpenSSL support
1481381105: Creating Vhost 'default' port 8080, 3 protocols, IPv6 off
1481381105: Using non-SSL mode
1481381105: Listening on port 8080
1481381105: mem: per-conn: 376 bytes + protocol rx buf
1481381105: canonical_hostname = mqtt
1481381105: Opening ipv4 listen socket on port 1883.
1481381105: Opening ipv6 listen socket on port 1883.
Here is the JavaScript source code:
<html>
<body>
<script src="mqttws31.js"></script>
<script>
try
{
// Create a client instance
console.log("Creating client object...");
client = new Paho.MQTT.Client("localhost", Number(8080), "manav");
//client = new Paho.MQTT.Client("test.mosquitto.org", Number(8080), "manav");
// set callback handlers
console.log("Setting handlers...");
client.onConnectionLost = onConnectionLost;
client.onMessageArrived = onMessageArrived;
// connect the client
console.log("Connecting...");
client.connect( {
onSuccess: onConnect,
mqttVersion: 4
});
}
catch (e)
{
console.log("Error: " + e.description);
}
// called when the client connects
function onConnect()
{
// Once a connection has been made, make a subscription and send a message.
console.log("Connected");
setTimeout( function() {
client.subscribe("world");
message = new Paho.MQTT.Message("Hello");
message.destinationName = "world";
client.send(message);
//client.disconnect();
}, 5000);
}
// called when the client loses its connection
function onConnectionLost(responseObject) {
if (responseObject.errorCode !== 0) {
console.log("Connection lost: " + responseObject.errorMessage);
}
}
// called when a message arrives
function onMessageArrived(message) {
console.log("Received Message: " + message.payloadString);
client.disconnect();
}
</script>
<h1>My MQTT Websockets Example</h1>
</body>
</html>

I see I am little bit late on answer.
MQTT's port for websocket is 1884 or something else, you have 8080. Maybe thats the problem.
Isnt 8080 a reserved TCP port?
Also, I know you have javascript code, but its paho. I was able to make publisher(it uses same class like subscriber so it must be on subscriber side too - this is just assumption though) work on websockets with paho python client which must be initialized with defining transport parameter. -> communicating with browser(see below for javascript)
mqtt.Client(transport='websockets')
Leaving that parameter MQTT assumes using TCP
mqtt.Client()
Also:
Config on my broker:
# Place your local configuration in /etc/mosquitto/conf.d/
#
# A full description of the configuration file is at
# /usr/share/doc/mosquitto/examples/mosquitto.conf.example
pid_file /var/run/mosquitto.pid
persistence true
persistence_location /var/lib/mosquitto/
log_dest file /var/log/mosquitto/mosquitto.log
include_dir /etc/mosquitto/conf.d
listener 1883
listener 1884
protocol websockets
I found my very old Javascript with paho-mqtt. It was working, so I just put it here.
Its subscriber and publisher at the same time. Together with the config, It was working like charm.
class sub{
constructor(hostname,port,clientid,topic){
this.buffer = []
this.hostname=hostname;
this.port=port;
this.clientid = clientid;
this.topic = topic;
this.client = new Paho.MQTT.Client(hostname,port, clientid);
// set callback handlers
this.client.onConnectionLost = this.onConnectionLost;
this.client.onMessageArrived = this.onMessageArrived.bind(this);
// connect the client
this.client.connect({onSuccess:this.onConnect});
}
onConnect(){
console.log('OnConnect');
}
onConnectionLost(responseObject) {
if (responseObject.errorCode !== 0) {
console.log("onConnectionLost:"+responseObject.errorMessage);
}
}
onMessageArrived(message) {
console.log("onMessageArrived:"+message.payloadString);
this.buffer.push(JSON.parse(message.payloadString));
}
subsribe(){
this.client.subscribe(this.topic)
}
publish(message){
console.log(message)
var mg = new Paho.MQTT.Message(JSON.stringify(message));
mg.destinationName = this.topic;
this.client.send(mg);
}
}
var x
x = new sub('xx.xx.xx.xx',1884,'clientID','LED');
function on(){
x.publish({'LED':'ON'});
}
function off(){
x.publish({'LED':'OFF'});
}

Firefox Nodejs Websocket

I am using Aurora 17, Chrome 22 and Firefox 16 and I am trying to create a simple chat app. I am using Node 0.8.9.
Firefox is getting the error that it cannot connect giving the error
Firefox can't establish a connection to the server at ws://localhost/.
I also tried it with the port and it have the same message
Firefox can't establish a connection to the server at ws://localhost:4444/.
Here is my code:
Server Code:
var http = require('http');
var net = require('net');
function onRequest(req, res) {
// Does enough to render a page and javascript
}
http.createServer(onRequest).listen(4444);
var socket = new net.Socket();
socket.connect(4444, "localhost", function(){
console.log("Socket Connected");
});
socket.on("message", function(message){
console.log(message);
});
Client Code:
var WebSocket = window.WebSocket || window.MozWebSocket;
var connection = new WebSocket('ws://localhost:4444');
connection.onopen = function() {
// Never runs
alert("This never runs :(")
}
connection.onerror = function(error) {
// Always runs here
console.log(error)
}
I get an output that the Socket is connect from the log statement on the server but Firefox cannot connect to the socket.
On Chrome, there is no error but the "onopen" is never fired. Using connection.send("a message") does not send anything to the server and returns false.

You're creating an ordinary TCP client socket in your server code and connecting it to your HTTP server. That's not at all the same thing as creating a WebSocket server that a browser can connect to. Use a library designed for the purpose (socket.io is very commonly used, since it can fall back to alternate transports when a browser doesn't support WebSockets).