appcast.js

/*
AppCast Dowloader (c) 2010 Sofa BV (Koen Bok)

Description:

	Returns the url for the latest version in an AppCast url.

Requirements:
	
	jQuery > 1.4

Example:
	
	$("#button").click(function() {
		downloadLatest("http://files.madebysofa.com/public/Enstore/ETUUpdates/appcast.xml");
	});
	

*/

function downloadLatest(appcastURL) {
	
	var highestVersion = 0;
	var downloadURL = '';
	
	function handleError() {
		alert("Could not retreive download link for: " + appcastURL);
	}
	
	$.ajax({
		type: "GET",
		url: appcastURL,
		dataType: "xml",
		error: handleError,
		success: function(xml) {

			$(xml).find("enclosure").each(function() {
				
				var node = $(this);
				
				var version = parseInt(node.attr("sparkle:version"));
				var url = node.attr("url");
				
				if (version > highestVersion) {
					highestVersion = version;
					downloadURL = url;
				}
			});
	
			// At this point we should have a download url
			if (downloadURL.indexOf("http") == -1) {
				handleError()
			} else {
				window.location = downloadURL;
			}
			
		}
	});
}