When you find yourself using a different URL each time, you can easily incorporate the new URL by utilizing the addEventSource function.
If your goal is to work with the same URL, you have the option of retrieving all events (both old and new) through the refetchEvents method.
An alternative approach involves obtaining the JSON data and initiating client-side event creation using renderEvent. This method provides a more dynamic, AJAX-like solution. By having your data source return the necessary JSON for events, you can loop through the array of new events and call renderEvent on each one.
// Include this code in a timer or whenever an action prompts
// the retrieval of new events
$.ajax({
url: "path/to/event/source",
success: function(data){
$.each(data, function(index, event)
$('#calendar').fullCalendar('renderEvent', event);
);
}
});