Use jquery callback instead of RPC in SignalR hub

Question

I need to subscribe to the same hub several times from different places, e.g.:

function firstPlace(targetHub){
  targetHub.client.onSomeEvent = function(data){
     alert('hello from first place');
  };
}
function secondPlace(targetHub){
  targetHub.client.onSomeEvent = function(data){
     alert('hello from second place');
  };
}

firstPlace($.connection.clientHub);
secondPlace($.connection.clientHub);

I'd like to have functionality based on callbacks (like jquery callbacks).

function firstPlace(targetHub){
  targetHub.client.onSomeEvent.add(function(data){
     alert('hello from first place');
  });
}
function secondPlace(targetHub){
  targetHub.client.onSomeEvent.add(function(data){
     alert('hello from second place');
  });
}


firstPlace($.connection.clientHub);
secondPlace($.connection.clientHub);

I know it can be easily implemented using some proxy object, but maybe there are some javascript magic that i'm not aware of?

Answer 1

If you don't help yourself, no one else will =). Here is the code, that solve my problem:

signalR.FunctionToCallback = new function() {
  self.MapCallback = function (sourceFunction, targetCallback) {
      if (!sourceFunction) {
          sourceFunction = function () {
              sourceFunction.callbacks.fireWith(this, $.makeArray(arguments));
          };
      }
      if (!sourceFunction.callbacks) {
          sourceFunction.callbacks = $.Callbacks();
      }
      sourceFunction.callbacks.add(targetCallback);
      return sourceFunction;
  };
};

Usage example:

function firstPlace(targetHub){
  targetHub.client.onSomeEvent = ko.FunctionToCallback.MapCallback(targetHub.client.onSomeEvent,function(data){
     alert('hello from first place');
  });
}
function secondPlace(targetHub){
  targetHub.client.onSomeEvent = ko.FunctionToCallback.MapCallback(targetHub.client.onSomeEvent, function(data){
     alert('hello from second place');
  });
}
firstPlace($.connection.clientHub);
secondPlace($.connection.clientHub);