Develop Reference

SignalR - Connection stopped when multiple tabs are opened - Message is incomplete

On the frontend of my application I use the #microsoft/signalr library to send off requests to my backend hubs. This works okay in a single tab, but when a second tab is open an error is outputted to the console of the first tab and the connection stops. It's almost as if the second tab is taking over for some reason, when really I believe both should be connected to the hub on different connections with different connection ids. The error I receive in the console is as follows:
[2021-04-23T09:34:22.762Z] Information: WebSocket connected to wss://localhost:6001/ptwHub?id=39HKWle3NU0eTjFxcNWsiQ.
Utils.js:218 [2021-04-23T09:34:32.895Z] Error: Connection disconnected with error 'Error: Message is incomplete.'.
./node_modules/#microsoft/signalr/dist/esm/Utils.js.ConsoleLogger.log # Utils.js:218
./node_modules/#microsoft/signalr/dist/esm/HttpConnection.js.HttpConnection.stopConnection # HttpConnection.js:542
transport.onclose # HttpConnection.js:479
./node_modules/#microsoft/signalr/dist/esm/WebSocketTransport.js.WebSocketTransport.close # WebSocketTransport.js:189
webSocket.onmessage # WebSocketTransport.js:129
ptw.ts:22 Error: Message is incomplete.
at Function../node_modules/#microsoft/signalr/dist/esm/TextMessageFormat.js.TextMessageFormat.parse (TextMessageFormat.js:13)
at JsonHubProtocol../node_modules/#microsoft/signalr/dist/esm/JsonHubProtocol.js.JsonHubProtocol.parseMessages (JsonHubProtocol.js:36)
at HubConnection../node_modules/#microsoft/signalr/dist/esm/HubConnection.js.HubConnection.processIncomingData (HubConnection.js:507)
at WebSocketTransport.HubConnection.connection.onreceive (HubConnection.js:73)
at WebSocket.webSocket.onmessage (WebSocketTransport.js:126)
The code to connect to the hub is as follows:
let connection = new signalR.HubConnectionBuilder().withUrl("https://localhost:6001/hub").build();
connection.on('knowledgeBaseUpdated', (userId: number) => {
alert(`User ${userId} has updated the knowledge base. Please refresh.`);
});
connection.start().catch(err => console.log(err));
Really not sure why the second tab would just take over the connection instead of creating a new connection. There is obviously an issue here somewhere but I'm really not sure where so any help would be really appreciated.
EDIT
I've enabled client side debugging for signalr and get the following output. The line which starts with HttpConnection.stopConnection is the line which appears when a new connections is attempted from a different tab.
[2021-04-26T09:50:00.084Z] Debug: Starting HubConnection.
Utils.js:228 [2021-04-26T09:50:00.096Z] Debug: Starting connection with transfer format 'Text'.
Utils.js:228 [2021-04-26T09:50:00.099Z] Debug: Sending negotiation request: https://localhost:6001/ptwHub/negotiate?negotiateVersion=1.
Utils.js:228 [2021-04-26T09:50:00.365Z] Debug: Selecting transport 'WebSockets'.
Utils.js:224 [2021-04-26T09:50:00.667Z] Information: WebSocket connected to wss://localhost:6001/ptwHub?id=14d1O9-cj544_-SHeZ2fgw.
Utils.js:228 [2021-04-26T09:50:00.667Z] Debug: The HttpConnection connected successfully.
Utils.js:228 [2021-04-26T09:50:00.668Z] Debug: Sending handshake request.
Utils.js:224 [2021-04-26T09:50:00.669Z] Information: Using HubProtocol 'json'.
Utils.js:228 [2021-04-26T09:50:13.079Z] Debug: Server handshake complete.
Utils.js:228 [2021-04-26T09:50:13.081Z] Debug: HttpConnection.stopConnection(Error: Message is incomplete.) called while in state Connected.
Utils.js:218 [2021-04-26T09:50:13.081Z] Error: Connection disconnected with error 'Error: Message is incomplete.'.
./node_modules/#microsoft/signalr/dist/esm/Utils.js.ConsoleLogger.log # Utils.js:218
./node_modules/#microsoft/signalr/dist/esm/HttpConnection.js.HttpConnection.stopConnection # HttpConnection.js:542
transport.onclose # HttpConnection.js:479
./node_modules/#microsoft/signalr/dist/esm/WebSocketTransport.js.WebSocketTransport.close # WebSocketTransport.js:189
webSocket.onmessage # WebSocketTransport.js:129
Utils.js:228 [2021-04-26T09:50:13.082Z] Debug: HubConnection.connectionClosed(Error: Message is incomplete.) called while in state Connecting.
Utils.js:228 [2021-04-26T09:50:13.083Z] Debug: Hub handshake failed with error 'Error: Message is incomplete.' during start(). Stopping HubConnection.
Utils.js:228 [2021-04-26T09:50:13.083Z] Debug: Call to HttpConnection.stop(Error: Message is incomplete.) ignored because the connection is already in the disconnected state.
Utils.js:228 [2021-04-26T09:50:13.084Z] Debug: HubConnection failed to start successfully because of error 'Error: Message is incomplete.'.
When the connection starts on a particular tab, I can see the connection has started and I get a single message when I look at the Network tab of Chrome Dev Tools. When I open the second tab, another message is sent to the first time which looks like an error message.. it weirdly contains a load of red dot characters? I
mage attached below. Please ignore the fact it's called ptwHub as I removed the ptw part previously to make it easier for the readers to understand.

Node JS VPN connect to endpoint

I hope you can help!
I have setup and Amazon echo applcation, the application makes a request to and AWS EC2 instance and gets JSON data as a response, this is working as expected however the use case for the final application is to connect to a private IP sending paramaters to an API to return the same JSON DATA.
for many reasons sadly I cannot share any of the endpoint information.
I need my NODE.js Application to make a request to the private IP over a VPN connection, Im currently using OPENVPN to make local requests to the endpoint.
I have looked at node packages to see if this is possible but I cannot seem to find one, except for this package here
https://www.npmjs.com/package/node-openvpn
This package is has a dependancy thats fails to download, so i got the node_module manually but Im getting an error when i try to execute the code
var openvpnmanager = require('node-openvpn');
var opts = {
host: 'xx.xx.xx.xx', // normally '127.0.0.1', will default to if undefined
port: 443, //port openvpn management console
timeout: 1500, //timeout for connection - optional, will default to 1500ms if undefined
logpath: 'log.txt' //optional write openvpn console output to file, can be relative path or absolute
};
var auth = {
user: '*******',
pass: '*******',
};
var openvpn = openvpnmanager.connect(opts)
openvpn.on('connected', function() { //will be emited on successful interfacing with openvpn instance
openvpnmanager.authorize(auth);
});
openvpn.on('console-output', function(output) { //emits console output of openvpn instance as a line
console.log(output)
});
openvpn.on('state-change', function(state) { //emits console output of openvpn state as a array
console.log(output)
});
// openvpnmanager.getLog(console.log) //get all console logs up to this point
// and finally when/if you want to
// openvpnmanager.disconnect();
openvpn.on('disconnected', function() { //emits on disconnect
openvpnmanager.destroy() //finally destroy the disconnected manager
});
this just gives me an error
Unhandled rejection TypeError: Cannot read property 'writable' of undefined
at Telnet.exec (C:\Users\user\Desktop\alexa- po\node_modules\node-openvpn\node_modules\telnet-client\lib\telnet- client.js:90:24)
If anybody has any suggetions on how to make this possible I would be very grateful.

NodeJS Sockets Sometimes Working

So, I have a node server, running expressjs io (uses socket.io), and I'm building a grid map that tracks coordinates in a database.
Only, I've run into a peculiar issue in that my sockets only listen sometimes.
At first there was no error message, and only by chance I let the page run and I got this error.
Uncaught TypeError: Cannot call method '0' of undefined UkPS99A_w96Ae0K570Nt?t=1395276358213&i=0:1
When I click on the file UkPS99A_w96Ae0K570Nt?t=1395276358213&i=0:1 I get this code:
io.j[0]("8::");
If I refresh the page, every few times it will suddenly work find for about 10 tile clicks, and then it stops working. My database is updating properly until the sockets basically die out.
Here is where I send the coordinates in my map:
io.emit("move", {x:this.x,y:this.y});
Server listening:
app.io.route('move', function(req) {
con.getConnection(function(err){
if (err) console.log("Get Connection Error.. "+err);
//removed query because redundant
req.io.emit("talk", {x:req.data.x,y:req.data.y});
});
});
and my socket script:
io.on("talk",function(data) {
console.log(data.x,data.y);
});
My script includes are at the bottom of the page in this order:
<script src="socket.io/socket.io.js"></script>
<script>io = io.connect();</script> <!-- open the socket so the other scripts can use it -->
<script src="../js/sock.js"></script>
<script src="../js/map.js"></script>
Is there something I'm doing wrong to that the socket seems to lose connection and throw some sort of error?
Update: I left the server running longer and a couple more error messages popped up in my console:
Uncaught TypeError: Cannot call method 'close' of null socket.io.js:1967
Uncaught TypeError: Cannot call method 'close' of null socket.io.js:1967
Uncaught TypeError: Cannot call method 'onClose' of null
More update: altered the connection line and added the proper CORS to my server.js
io = io.connect('http://sourceundead.com', {resource : 'socket.io'});
Still the same issue.

You seem to have a connection attrition as you never release them to the pool.
Assuming con is the (bad) name of your pool, instead of
app.io.route('move', function(req) {
con.getConnection(function(err){
if (err) console.log("Get Connection Error.. "+err);
//removed query because redundant
req.io.emit("talk", {x:req.data.x,y:req.data.y});
});
});
you should have something like
app.io.route('move', function(req) {
con.getConnection(function(err, connection){
if (err) console.log("Get Connection Error.. "+err);
//removed query because redundant
req.io.emit("talk", {x:req.data.x,y:req.data.y});
connection.release();
});
});
Be careful that using connections must be done with care to ensure they're always released, and it's a little tedious to do especially when handling errors as soon as you have a few queries to do when doing a task.
At some point you might want to use promises to make that easier. Here's a blog post about using bound promises to ease database querying in node.js.

SignalR not hitting OnConnected and giving Newtonsoft.Json.JsonReaderException

I am trying to setup SignalR at my ASP.NET MVC site and a Javascript client.
This is my client:
#section scripts{
<script src="~/Scripts/jquery.signalR-2.0.2.min.js"></script>
<script type="text/javascript">
$(function () {
var connection = $.connection('/MY_ENDPOINT');
connection.received(function (data) {
$('#chatArea').append('>>' + data + "\r\n");
});
connection.start().done(function () {
$("#send").click(function () {
connection.send($('#msg').val());
$("#msg").val("");
});
});
connection.error(function (e) {
console.log(e);
});
});
</script>
}
Of course, I have the corresponding HTML elements chatArea and msg. In server, here is what I did:
Installed SignalR (latest version currently, 2.0.2) through NuGet.
Added app.MapSignalR("MY_ENDPOINT", new Microsoft.AspNet.SignalR.HubConfiguration()); in startup configuration, made sure it is called before registering auth methods.
I've subclassed PersistentConnection and overridden OnConnected and OnReceived methods.
However, when I run my app and navigate to the page, I can see that my endpoint's negotiate and connect methods are called, they both return OK (HTTP 200). I try to send anything using the webpage by clicking the "send" button, and at the server side I'm getting this error:
A first chance exception of type 'Newtonsoft.Json.JsonReaderException'
occurred in Newtonsoft.Json.dll
Additional information: Unexpected character encountered while
parsing value: a. Path '', line 0, position 0.
What could be the cause of this error?
UPDATE: I also have an iOS app with the SignalR-ObjC framework, and I can connect. However, when I try to send any data over it, I'm getting:
2014-03-06 19:39:39.853 Tanisalim[54987:70b] Websocket error: Error Domain=AFNetworkingErrorDomain Code=-1011 "Request failed: internal server error (500)" UserInfo=0xade84e0 {NSErrorFailingURLKey=http://10.211.55.3/api/socket/send?transport=longPolling&connectionData=(null)&connectionToken=xybYQ8ItTN0IWUbyrosuHy%2F3jN0krIyHLO6b6Gq8VdC3orwRRGkVSIgtYkNQINVLhRMW77cX%2BU2LiHxoe0eDE3ZumT7JrObJcQ%2FXyHiP25%2BQy%2BZizHEHbsPyBBomERoI, NSLocalizedDescription=Request failed: internal server error (500), NSUnderlyingError=0xade1290 "Request failed: unacceptable content-type: text/html"
Still, no server-side breakpoints are hit.

Node js + Sails js + websocket app crashing every few hours

I am having a problem similar to socket.io issue using sails.js. Every once in a while (once per day, or even few hours, it varies), a visitor to the web site/app will crash Node, seemingly due to the way his websocket client tries to connect. Anyway, here's the crash log:
debug: Lowering sails...
/Volumes/Two/Sites/lsdfinder/node_modules/sails/node_modules/express/node_modules/connect/lib/utils.js:216
return 0 == str.indexOf('s:')
^
TypeError: Cannot call method 'indexOf' of undefined
at exports.parseSignedCookie (/Volumes/Two/Sites/lsdfinder/node_modules/sails/node_modules/express/node_modules/connect/lib/utils.js:216:19)
at Manager.socketAttemptingToConnect (/Volumes/Two/Sites/lsdfinder/node_modules/sails/lib/hooks/sockets/authorization.js:35:26)
at Manager.authorize (/Volumes/Two/Sites/lsdfinder/node_modules/sails/node_modules/socket.io/lib/manager.js:910:31)
at Manager.handleHandshake (/Volumes/Two/Sites/lsdfinder/node_modules/sails/node_modules/socket.io/lib/manager.js:786:8)
at Manager.handleRequest (/Volumes/Two/Sites/lsdfinder/node_modules/sails/node_modules/socket.io/lib/manager.js:593:12)
at Server.<anonymous> (/Volumes/Two/Sites/lsdfinder/node_modules/sails/node_modules/socket.io/lib/manager.js:119:10)
at Server.EventEmitter.emit (events.js:98:17)
at HTTPParser.parser.onIncoming (http.js:2076:12)
at HTTPParser.parserOnHeadersComplete [as onHeadersComplete] (http.js:120:23)
at Socket.socket.ondata (http.js:1966:22)
9 Oct 10:42:24 - [nodemon] app crashed - waiting for file changes before starting...
In config/sockets.js, authorization is set to true. Not sure what else to do, where to fix this. Any suggestions? I can read the Sails docs too, but this appears to be a problem in Express/Connect, no? Thanks.
...René

The problem is that once every so often, a client will connect that has no cookies. Sails.js is using util.parseSignedCookie() from Connect without checking for errors, and therefore an error is thrown. This is what it looks like in Sails:
if (handshake.headers.cookie) {
handshake.cookie = cookie.parse(handshake.headers.cookie);
handshake.sessionID = parseSignedCookie(handshake.cookie[sails.config.session.key], sails.config.session.secret);
}
If you take a look into the cookieParser() middleware of Connect, you can see error checking is required:
if (cookies) {
try {
req.cookies = cookie.parse(cookies);
if (secret) {
req.signedCookies = utils.parseSignedCookies(req.cookies, secret);
req.signedCookies = utils.parseJSONCookies(req.signedCookies);
}
req.cookies = utils.parseJSONCookies(req.cookies);
} catch (err) {
err.status = 400;
return next(err);
}
}
I've created a Gist here that fixes the problem, and will submit a pull request to Sails.js when I have the time. The Gist uses Connect's cookieParser() middleware to automatically handle errors. If you want to use this, modify this file in your modules folder:
node_modules/sails/lib/hooks/sockets/authorization.js

If you are doing a crossdomain request, you could turn off authorization.
In *site_dir/config/sockets.js* set authorization to false. One way of doing it. You can also call your api with something like this
bash
**http://localhost:1337?cookie=smokeybear**
Its is in the comments on the sockets.js file.