SignalR cannot invoke client listening function

Question

So I am trying to implement SignalR in a project my code is as follows:

MtHub.cs:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using Microsoft.AspNet.SignalR;
using Microsoft.AspNet.SignalR.Hubs;

namespace HaldanMT
{
    public class MtHub : Hub
    {
        public void RemoveResource(string message)
        {
            Clients.All.RemoveResource(message);
        }
    }
}

custom.js:

$(document).ready(function () {
    $.connection.mtHub.client.removeResource = function (message) { // This is the client listener that will fire once the server invokes the message. This is not taking place
        console.log("finished");
        RemoveResource(message); // Function to be invoked once the signalR message has been received from the server
    }
});
function RemoveSelf(message){
  $.connection.hub.start()
     .done(function () {
        console.log("Fire SignalR");
        $.connection.mtHub.server.removeResource(message); // Invoke the SingalR server function that would in turn invoke the client listening function
          })
          .fail(function () {
            console.log("Error With SignalR");
          });
    }
function RemoveResource(message){
  alert(message); // Display message
}

HTML:

<button onclick="RemoveSelf('This is a message');">Click Me</button>

<script src="~/Scripts/jquery-1.10.2.js"></script>
<script src="~/Scripts/jquery.signalR-2.2.1.js"></script>
<script src="/signalr/hubs" type="text/javascript"></script>
<script src="~/Scripts/custom.js" type="text/javascript"></script>

Now...The correct function is fired on the button click event but the response to the client does not get invoked. If I place the SignalR invoking js function within the document ready surrounded by the onclick event of the button it works just fine. But I require the SignalR invoking js function to be fired in the function RemoveSelf(message) as other things need to take place within my code.

So my question is: Does SignalR require the server side code to be invoked via a element listener, and not within a standard function. Most examples I find are using jquery event based listeners and not a traditional function.

Thank you in advance.

Mark C. · Accepted Answer · 2016-08-31 18:14:39Z

2

The SignalR Server side code does not require invocation via element listener, but that's kind of a double-edge sword because JavaScript essentially works off events.

Your code should work exactly as it sits, but here's my code exactly and it works 100% (I don't see really many differences between our code. Could just be a typo somewhere) :

Hub

[HubName("mtHub")]
public class MtHub : Hub
{
    public void RemoveResource()
    {
        Clients.All.RemoveResource("yo");
    }
}

JavaScript (this is code inside client-side.js)

$(function() {
    $.connection.mtHub.client.removeResource = function () {
        alert("see it worked");
    }
});

var CallIt = function() {
    var connection = $.connection.mtHub;

    $.connection.hub.start().done(function () {
        alert("connected");

        connection.server.removeResource().done(function () {
            console.log("hi");
        });

    });
}

HTML

<h2 onclick="CallIt()">Fun Stuff</h2>
@Scripts.Render("~/bundles/jquery")
@Scripts.Render("~/bundles/bootstrap")
<script src="~/Scripts/jquery.signalR-2.2.1.js"></script>
<script src="~/signalr/hubs"></script>
<script src="~/Scripts/client-side.js"></script>

If this doesn't work, can you let me know what errors you get?

answered Aug 31, 2016 at 18:14

Mark C.

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4 Comments

Rossco Over a year ago

Thanx so much for the answer. Ok so I set it up this way which you are right is very similar to the way I'm doing it. I open two browsers to simulate the functionality. All seems to work fine on the browser thats invoking the SignalR hub function but nothing seems to happen on the client listening function. The order in which the console.log meesages appear are as follows: 1. Connected 2. Finished Firing SingalR (Aka client listening function invoked) 3. Firing SignalR invoking function. In my mind I would expect 3 and 2 to be switched around. I have no errors on my JS console. Thanx again

Mark C. Over a year ago

Are they on the same server / are you using a load balancer?

Rossco Over a year ago

Yeah they are on the same server...Its ok I'm just gonna use it via jQuery event listeners. I found a way to invoke the event listener within my functions and pass parameters. Thanx alot for your help though

Mark C. Over a year ago

That shouldn't be necessary.. Something is wrong with your configuration or something because this code works. I've verified and opened several different browser windows.

Kelso Sharp · Accepted Answer · 2016-09-02 20:54:12Z

0

Your client methods have the wrong casing for the method names, you are using "RemoveResource" and they should be "removeResource"

This is incorrect:

function RemoveResource(message){
   alert(message); // Display message
}

This should fix the problem:

function removeResource(message){
   alert(message); // Display message
}

answered Sep 2, 2016 at 20:54

Kelso Sharp

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