I am trying out SignalR, and i don't quite understand how to call methods from my client in a way that it calls the same hub.
i have two methods in my hub:
private ctlDataManager myManager;
public void StartConnection()
{
myManager = new ctlDataManager("test");
myManager.UpdateItemEvent += myManager_UpdateItemEvent;
myManager.Connect();
}
public void StopConnection()
{
myManager.Disconnect();
}
And in my client i try to call them like this:
var notificationHub = $.connection.notificationHub;
$.connection.hub.start()
.done(function (state) {
$("#submit").click(function (e) {
e.preventDefault();
notificationHub.server.startConnection();
return false;
});
$("#stop").click(function (e) {
e.preventDefault();
notificationHub.server.stopConnection();
return false;
});
});
Now when i click on the start button it works fine it starts it and receives data too.
But when i click the stop button it throws an instance of an object error.
It appears that 'myManager' is null. It's almost as a new hub were open. Naturally i need it to be the same one as i need to close the connection.
How can i do that?
From my understanding, the server-side hub class is not persisted. Therefore, the myManager object is created with each method call from a client. My advice would be to declare myManager elsewhere in your application that you can assure 100% up-time, and have your server-side hub methods communicate with it that way.
One way for you to verify this is to debug the constructor of your hub class. You will notice that it is called for every client->server-side method call.
Related
I'd like to know if an Hub method called from js client is
executed completely also if client disconnected during execution
For example..
public virtual void Join(int userId)
{
using (var context = new HubConnectionContext(this, RoomId, userId))
{
T workflow = GetWorkflow(context);
workflow.OnUserJoin();
}
}
I can be sure that the Dispose Method of HubConnectionContext is called also if client disconnect during using block?
I have the following TestHub that does nothing but invoke a client side sayHello() function.
public class TestHub:Hub
{
public void SayHello()
{
Context.Clients.All.sayHello();
}
public override Task OnConnected()
{
//do some custom stuff
return base.OnConnected();
}
}
On the client, I have the following:
var connection = $.hubConnection('http://localhost:12345/signalr');
var proxy = connection.createHubProxy('TestHub');
proxy.on('sayHello',function(){
console.log('sayHello fired');
})
connection.start().done(function(){
console.debug('Connected');
})
When I call SayHello() on my TestHub the client prints out the following perfectly fine
sayHelloFired
and when the proxy first loads, it prints the following to the console perfectly fine.
Connected
However, if I throw a breakpoint in the OnConnected() method on TestHub, then it does not hit.
All the posts discussing similar problems suggest that their is no handlers being subscribed on the client side, but that is not the case here. How could this be working and OnConnected() is never fired?
Your code didn't compile for me because of the
Context.Clients.All.sayHello();
Line. Context here tries to refer to Hub.Context which is an HubCallerContext class. I think you want to refer to Hub.Clients which is an IHubCallerConnectionContext.
I replaced that line to
Clients.All.sayHello();
And my breakpoint got invoked.
However I am surprised you made it run and got messages on console.
BTW You are right about that, when using javascript clients, if there is no subscription to any event in the hub, the OnConnected methond won't be invoked.
But that is not the case here.
I'm trying to learn SignalR by writing a really simple application... it basically sends "Hello" periodically (like the Stock Ticker, but a lot simpler).
Here's my hub:
public class StockTickerHub : Hub
{
public void Hello()
{
var s = StockTicker.stockTicker;
Clients.All.hello();
}
}
...and here's the code that is supposed to periodically send the messages:
public class StockTicker
{
public static StockTicker stockTicker = new StockTicker();
private Thread thread;
public StockTicker()
{
var stockTickerHub = GlobalHost.ConnectionManager.GetHubContext<StockTickerHub>();
this.thread = new Thread(() =>
{
while (true)
{
stockTickerHub.Clients.All().hello();
Thread.Sleep(1000);
}
}
);
this.thread.Start();
}
}
I'm getting a RuntimeBinderException at stockTickerHub.Clients.All().hello();. It says:
An unhandled exception of type 'Microsoft.CSharp.RuntimeBinder.RuntimeBinderException' occurred in System.Core.dll
Additional information: Cannot invoke a non-delegate type
What am I doing wrong?
Client-side JavaScript is below, just in case you need to replicate this.
<script type="text/javascript">
$(function () {
var chat = $.connection.stockTickerHub;
chat.client.hello = function () {
$("#log").append("Hello");
}
$.connection.hub.start().done(function () {
chat.server.hello();
});
});
</script>
Simply change:
stockTickerHub.Clients.All().hello();
to:
stockTickerHub.Clients.All.hello();
The debugger should have already tell you this error. I tried your code after the update. It is working.
A remark on the code design:
I wouldn't start a new sending thread in the hello event, that would start one every time this method is invoked by any client. I don't think that's what you want to do. As a smoother example you could start the ticker in Startup class. (If you want a ticker per connection override OnConnected, get the client's connection id and give them separate tickers...)
I'm using the latest version of SignalR (1.0.1). I am trying to broadcast from my controller to the hub and having a few issues:
My client does not seem to be getting messages.
It doesn't seem that my hub context even has an 'addMessage' defined:
My hub:
public class SignalRPriceHub : Hub
{
public void sndMessage(string msg)
{
Clients.All.addMessage(msg + "****");
}
}
Javascript client:
<script src="#Url.Content("~/Scripts/jquery.signalR-1.0.1.min.js")"></script>
<script src="~/signalr/hubs"></script>
.....
var myHub = $.connection.signalRPriceHub;
myHub.client.addMessage = function (message) {
alert(message);
};
Controller:
var context = GlobalHost.ConnectionManager.GetHubContext<SignalRPriceHub>();
context.Clients.All.addMessage("TestOutsideMessage!!!");
A few things I noticed:
1. My hub context doesn't seem to have an 'addMessage'
{"'Microsoft.AspNet.SignalR.Hubs.ClientProxy' does not contain a definition for 'addMessage'"} System.Exception {Microsoft.CSharp.RuntimeBinder.RuntimeBinderException}
If I run the following code from the same file as my client code above, I do get a message.
var myHub = $.connection.signalRPriceHub;
$.connection.hub.start(function () {
myHub.server.sndMessage("Hello World!");
});
Can anyone shed some light as to what might be happening? Thanks all!
I'll go over the faults in your initial application which shed light to why your second bullet point makes it all work.
In your javascript client you must start the connection:
$.connection.hub.start();
You must then request the message on your hub by calling the sndMessage command:
$.connection.hub.start().done(function() {
myHub.server.sndMessage("Hello world");
});
The reason why you do not see an addMessage function on your hub context is because the hub context .Clients.All is dynamic.
One last note, in order to make the sample work you also need to make sure that in your Application_Start you have RouteTable.Routes.MapHubs(); . I assume you already have this since once you add the connection start that everything works.
I am evaluating SignalR (which happens to be used with Knockoutjs) to see if we can use it to notify clients of concurrency issues. Basically user "a" saves a record and users "b,c,d,e,f,g" are notified. I basically have an example working that notifies all clients. So I think I am almost there.
I came across this link and it lead me on the current path that I am on. I have also been looking at the documentation on Github.
Basically I want to exclude the a single client from the Clients.method() call. I dont see a way to loop through the clients and check the ClientId. The only other I can see to accomplish this is to maybe look at using the groups to keep track of it, but that seemed a little cumbersome, but I was having issues with that as well.
public class TicketHub : Hub
{
static int TotalTickets = 10;
public void GetTicketCount()
{
AddToGroup("ticketClients");
Clients.setTicketCount(TotalTickets);
}
public void BuyTicket()
{
if (TotalTickets > 0)
TotalTickets -= 1;
RemoveFromGroup("ticketClients");
// This will call the method ONLY on the calling client
// Caller.updateTicketCountWithNotification(TotalTickets);
// This will call the method on ALL clients in the group
Clients["ticketClients"].updateTicketCountNotify(TotalTickets);
AddToGroup("ticketClients");
Caller.updateTicketCountDontNotify(TotalTickets);
}
}
javascript code:
<script type="text/javascript">
$(document).ready(function () {
var test = $.connection.test;
$("#btnTest").click(function () {
test.testMethod();
});
test.show = function (text, guid) {
if (guid != test.guid) //notify all clients except the caller
alert(text);
};
$.connection.hub.start(function () { test.start(); });
});
</script>
Class :
public class Test : Hub
{
public void Start()
{
Caller.guid = Guid.NewGuid();
}
public void TestMethod()
{
Clients.show("test", Caller.guid);
}
}
If you want to exclude the caller from the call to the client side method you can use:
Clients.Others.clientSideMethod();
There is also Clients.AllExcept(...) that allows excluding certain people.