SignalR client with multiple connections

Question

I have multiple SignalR 'services' running and only one UI to access them.

How can I make the client js to talk to multiple connections with different Url? Because it seems I can only specify one url per $.connection.hub, and I can't use multiple 'signalr/hubs' client scripts.

Any help? Thanks.

Answer 1

$.connection.hub is created in the /signalr/hubs inclusion.

At the end of the file it essentially does:

$.connection.hub = $.hubConnection("/signalr", { useDefaultPath: false });

To create the hub proxy you do:

var myHub = $.connection.hub.createHubProxy('myHub');

Simple example for multiple connections:

var connection1 = $.hubConnection("http://www.myfirstendpoint.com");
var connection2 = $.hubConnection("http://www.mysecondendpoint.com");

var myCon1Hub = connection1.createHubProxy('myCon1Hub');
var myCon2Hub = connection2.createHubProxy('myCon2Hub');

myCon1Hub.client.foo = function() { ... Whatever you want ... };
myCon2Hub.client.foo = function() { ... Whatever you want ... };

connection1.start();
connection2.start();

Answer 2

My solution for such occasions:

var SignalRHelpers = function () {
  var _connectionDeferred;

  var subscribeToConnectionStart = function (callback) {
    if (!_connectionDeferred)   // start connection if not yet initialized
        _connectionDeferred = $.connection.hub.start();

    if ($.connection.hub.state == $.connection.connectionState.connected && callback) {
        // already connected
        callback();
    } else if (callback) {
        // register handler
        _connectionDeferred.done(callback);
    }
  };

  return {
    SubscribeToConnectionStart: subscribeToConnectionStart
  };
}();

It internally stores the promise object from start() and attaches handlers as needed.

Basically you just call SignalRHelpers.SubscribeToConnectionStart every time you need to connect. For example

SignalRHelpers.SubscribeToConnectionStart(function(){
    someHub.server.executeSomething();
});