I am trying to connect to Local SQL Server database using Tedious in node js.
function connectToSql() {
sqlConnection.on('connect', function (err) {
// If no error, then good to go...
if (err) {
console.log(err);
} else {
console.log('connected to SQL!');
executeSelectStatement();
}
});
}
When I am invoking this function soon after its declaration, its working fine and prints 'connected to SQL!'. But when I am calling this function "connection" event of SocketIO.Server its not making sql call. My code is as below:
ioServer.on('connection', function (socket: SocketIO.Socket) {
console.log('a user connected');
connectToSql();
});
it only prints 'a user connected'
Any suggestions why is this happening?
It is likely that the SQL connection has already been established before the Socket.io connection takes place. That being the case, the connect event has probably already happened.
If you're looking to only establish the SQL connection after receiving a Socket.io connection, you probably need to new Connection(config); at that time while also subscribing to the connect event.
Do note that you probably do not want to establish an SQL connection for every Socket.io connection as with multiple people utilizing the application, a lot of additional overhead is taking place where it likely does not need to.
Related
I have a ratchet server, that I try to access via Websocket. It is similar to the tutorial: logging when there is a new client or when it receives a message. The Ratchet server reports having successfully established a connection while the Kotlin client does not (the connection event in Kotlin is never fired). I am using the socket-io-java module v.2.0.1. The client shows a timeout after the specified timeout time, gets detached at the server and attaches again after a short while, just as it seems to think, the connection did not properly connect (because of a missing connection response?).
The successful connection confirmation gets reported to the client, if the client is a Websocket-Client in the JS-console of Chrome, but not to my Kotlin app. Even an Android emulator running on the same computer doesn´t get a response (So I think the problem is not wi-fi related).
The connection works fine with JS, completing the full handshake, but with an Android app it only reaches the server, but never the client again.
That´s my server code:
<?php
namespace agroSMS\Websockets;
use Ratchet\ConnectionInterface;
use Ratchet\MessageComponentInterface;
class SocketConnection implements MessageComponentInterface
{
protected \SplObjectStorage $clients;
public function __construct() {
$this->clients = new \SplObjectStorage;
}
function onOpen(ConnectionInterface $conn)
{
$this->clients->attach($conn);
error_log("New client attached");
}
function onClose(ConnectionInterface $conn)
{
$this->clients->detach($conn);
error_log("Client detached");
}
function onError(ConnectionInterface $conn, \Exception $e)
{
echo "An error has occurred: {$e->getMessage()}\n";
$conn->close();
}
function onMessage(ConnectionInterface $from, $msg)
{
error_log("Received message: $msg");
// TODO: Implement onMessage() method.
}
}
And the script that I run in the terminal:
<?php
use Ratchet\Server\IoServer;
use agroSMS\Websockets\SocketConnection;
use Ratchet\WebSocket\WsServer;
use Ratchet\Http\HttpServer;
require dirname(__DIR__) . '/vendor/autoload.php';
$server = IoServer::factory(
new HttpServer(
new WsServer(
new SocketConnection()
)
)
);
$server->run();
What I run in the browser for tests (returns "Connection established" in Chrome, but for some reason not in the Browser "Brave"):
var conn = new WebSocket('ws://<my-ip>:80');
conn.onopen = function(e) {
console.log("Connection established!");
};
conn.onmessage = function(e) {
console.log(e.data);
};
What my Kotlin-code looks like:
try {
val uri = URI.create("ws://<my-ip>:80")
val options = IO.Options.builder()
.setTimeout(60000)
.setTransports(arrayOf(WebSocket.NAME))
.build()
socket = IO.socket(uri, options)
socket.connect()
.on(Socket.EVENT_CONNECT) {
Log.d(TAG, "[INFO] Connection established")
socket.send(jsonObject)
}
.once(Socket.EVENT_CONNECT_ERROR) {
val itString = gson.toJson(it)
Log.d(TAG, itString)
}
}catch(e : Exception) {
Log.e(TAG, e.toString())
}
After a minute the Kotlin code logs a "timeout"-error, detaches from the server, and attaches again.
When I stop the script on the server, it then gives an error: "connection reset, websocket error" (which makes sense, but why doesn´t he get the connection in the first time?)
I also tried to "just" change the protocol to "wss" in the url, in case it might be the problem, even though my server doesn´t even work with SSL, but this just gave me another error:
[{"cause":{"bytesTransferred":0,"detailMessage":"Read timed out","stackTrace":[],"suppressedExceptions":[]},"detailMessage":"websocket error","stackTrace":[],"suppressedExceptions":[]}]
And the connection isn´t even established at the server. So this try has been more like a down-grade.
I went to the github page of socket.io-java-client to find a solution to my problem there and it turned out, the whole problem was, that I misunderstood a very important concept:
That socket.io uses Websockets doesn´t mean it is compatible with Websockets.
So speaking in clear words:
If you use socket.io at client side, you also need to use it at the server side and vice versa. Since socket.io sends a lot of meta data with its packets, a pure Websocket-server will accept their connection establishment, but his acknowledgement coming back will not be accepted by the socket.io client.
You have to go for either full socket.io or full pure Websockets.
When my client successfully connects to the hub, I want the client to immediately join a group. I have a method in my hub to do that, I just need an event handler for when the connection is established, just like
connection.start().done(
function () {
connection.invoke('JoinGroup', 'GroupName');
});
in SignalR for plain ASP.Net.
Can I do that or do I have to set a timer to do it after x seconds after the start(); call was made?
Edit:
I found out I can do
connection.start(
function (){
connection.invoke('JoinGroup', 'GroupName');
}
);
but it tells me that it Cannot send data if the connection is not in the 'Connected' State.
what do?
SignalR is notoriously difficult due to version mismatches etc.
Please see the following article: https://learn.microsoft.com/en-us/aspnet/core/tutorials/signalr?view=aspnetcore-2.1&tabs=visual-studio
In it, there's a section that specifies how to start (and wait for connection to be established):
var connection = new signalR.HubConnectionBuilder().withUrl("/chatHub").build();
connection.start().then(() => {
//try some stuff here :)
})
.catch(function (err) {
//failed to connect
return console.error(err.toString());
});
The javascript client uses promises that have to be resolved/rejected before you can use it.
The other option is to wrap inside async method and await the call (not sure if this will work correctly). Such as:
await connection.start();
//connection should be started now. beware of exceptions though
I am implementing a Network Test for my Web-application using OpenTok's js library.
To do that, I create a publisher, connect to session, then make a subscriber connect to the publisher's stream.
The Test is working on other browsers (I have tested Chrome and Internet Explorer) but on Firefox version 57.0.1 I get an error - 'The stream was unable to connect due to a network error. Make sure you have a stable network connection and that it isn't blocked by a firewall.'
Make sure when you create the OpenTok Session you are using a 'routed' Session, not a 'relayed' one. Also make sure you are passing the 'testNetwork' property to the subscribe method. Here is a working sample:
// Sample code
var session = OT.initSession(APIKEY, SESSIONID);
session.connect(TOKEN, function(err) {
if (err) {
alert(err.message);
return;
}
var publisher = session.publish();
publisher.on('streamCreated', function(event) {
session.subscribe(event.stream, null, {
testNetwork: true
}, function(err) {
if (err) alert(err.message);
});
});
});
https://jsbin.com/quruzac/edit
We are seeing a surprising scenario when we are on a slow network connection and our calls to the WL Server time out.
This happens at WL.Client.connect as well as on invokeProcedure:
we execute the call with a timeout of 10 seconds
the network connection is slow so the call times out
the defined onFailure procedure associated to that call is executed
the WL Server responds with a valid response after the timeout
the onSuccess procedure associated to that call is executed
Is this the designed and intended behavior of the WL Client Framework? Is this specified in the InfoCenter documentation or somewhere?
All developers in our team expected these two procedures to be exclusive and our code was implemented based on this assumption. We are now investigating options on how to match a timed-out/failed response to a success response to make sure we achieve an exclusive execution of onFailure or onSuccess code/logic in our app.
Note: we did not test that with connectOnStartup=true and since the initOptions does not provide an onSuccess procedure (since WL handles that internally) it might be even harder to implement an exclusive execution in this case.
That seems like expected behavior, but don't quote me on that.
You can get the behavior you want (only call the failure callback when it fails, and only call the success callback when it succeeds) using jQuery.Deferreds. There are ways of creating these deferred objects with dojo and other libraries. But, I just tested with jQuery's implementation, which is shipped with every version of IBM Worklight.
$(function () {
var WL = {};
WL.Client = {};
WL.Client.invokeProcedureMock = function (options) {
options.onFailure('failure');
options.onSuccess('success');
};
var dfd = $.Deferred();
var options = {
onSuccess: dfd.resolve,
onFailure: dfd.reject
};
WL.Client.invokeProcedureMock(options);
dfd
.done(function (msg) {
// handle invokeProcedure success
console.log(msg);
})
.fail(function (msg) {
//handle invokeProcedure failure
console.log(msg);
});
});
I put the code above in a JSFiddle, notice that even if I call the onSuccess callback, it won't have any effect because I already called the failure callback (which rejected the deferred). You would add your application logic inside the .done or .fail blocks.
This is just a suggestion, there are likely many ways to approach your issue.
I'm using SignalR 1 with MVC4 C# web application with form authentication.
I have a code in my layout page in JavaScript :
$(documnet).ready(function(){
connect to hub code ...
})
I want to disconnect a user form the hub and start connect again after he does a login and validate ok.
I want to do it from server side inside my account controller and method :
public ActionResult LogOn(LoginModel model, string returnUrl)
{
if (ModelState.IsValid)
{
if (System.Web.Security.Membership.ValidateUser(model.UserName, model.Password))
{
FormsAuthentication.SetAuthCookie(model.UserName, false);
....here , disconnect from hub
....to make the user reconnect
}
The reason I want to do it is because SignalR throws an error if user changed to authenticated after login and the connection remains . The error is:
The connection id is in the incorrect format.
You cannot stop and start SignalR connections from the server. You will need to call
$.connection.hub.stop(); //on the client before the user attempts to log on and then call
$.connection.hub.start(); //after the log on attempt has completed.
One way you could do what you ask is to write a disconnect event on your client that the server can call through SignalR. Maybe something somewhat like this:
myHub.client.serverOrderedDisconnect = function (value) {
$.connection.hub.stop();
};
Then, on the server, something like this:
Clients.Client(Context.ConnectionId).serverOrderedDisconnect();
If someone is still looking for solution(SignalR version 2.4.1):
GlobalHost.DependencyResolver.Resolve<ITransportHeartbeat>().GetConnections().First(c => c.ConnectionId == "YourId").Disconnect();
Try controlling everything from javascript. The following is a logout example, login would be similar.
From http://www.asp.net/signalr/overview/security/introduction-to-security:
If a user's authentication status changes while an active connection
exists, the user will receive an error that states, "The user identity
cannot change during an active SignalR connection." In that case, your
application should re-connect to the server to make sure the
connection id and username are coordinated. For example, if your
application allows the user to log out while an active connection
exists, the username for the connection will no longer match the name
that is passed in for the next request. You will want to stop the
connection before the user logs out, and then restart it.
However, it is important to note that most applications will not need
to manually stop and start the connection. If your application
redirects users to a separate page after logging out, such as the
default behavior in a Web Forms application or MVC application, or
refreshes the current page after logging out, the active connection is
automatically disconnected and does not require any additional action.
The following example shows how to stop and start a connection when
the user status has changed.
<script type="text/javascript">
$(function () {
var chat = $.connection.sampleHub;
$.connection.hub.start().done(function () {
$('#logoutbutton').click(function () {
chat.connection.stop();
$.ajax({
url: "Services/SampleWebService.svc/LogOut",
type: "POST"
}).done(function () {
chat.connection.start();
});
});
});
});
You can the hub context to abort() the connection directly in .Net Core
Context.Abort();
See the method below
https://learn.microsoft.com/en-us/dotnet/api/microsoft.aspnetcore.signalr.hubcallercontext.abort
Try this:
public ActionResult LogOn(LoginModel model, string returnUrl) {
if (ModelState.IsValid) {
if (System.Web.Security.Membership.ValidateUser(model.UserName, model.Password)) {
FormsAuthentication.SetAuthCookie(model.UserName, false);
connection.Stop();
}
}
Assuming your connection handle is connection. The challenge is accessing a handle to your connection object in your Action Method.
Copy and paste the following function into your Hub
Use HttpContext.Current.Response.End();
to force the client to disconnect in your hub