[needs documentation] CTools Command Response Cache

This time, tested patch with more then one ctools-use-modal-cache link and realized a minor error with the .each.

ok so here is the generalization for any ctools command. I have used it and tested it with both modal and non modal commands. I have to tell ya, its sexy.....

Been think aobut it some more. Perhaps we create a jquery event ('ctools-cached'). Then in warm cache, it fetches the result and fires off that event.

This then allows the click functions to do

if (hasClass(ctools-fetching) {
  $(this).bind('ctools-cached', respond)
}

That way we don't hit the server twice for the same link (one when its trying to cache, and the other when its not cached yet but user clicked).

Ok so followed up on my last comment. What the real point of that change is to prevent a user from clicking a cachable link before the result has been cached. Thus creating TWO hits on the url, one for the cache warming and one for the user click.

This patch addresses that point, when a user clicks and its ctools-fetching, it binds to the ctools-cache-warm event to render the display. Thus waiting for the cache result to return.

tiny code style change (4 spaces instead of 2 on one of the lines.)

I agree, instead of an Array() we use an Object(). and then we can do .commandCache[url] = data.

then we have to manage a set of links, triggering ctools-warm-cache on all of them that match as well as setting ctools-fetching on all the ones that do match but didn't init the ajax call.

Some management that can go in there, that while, complicated is totally doable and desirable.

So this next installment :-D, achieves the following.
For three links that goto user/login/nojs?destination=user, it does exactly one request to that url and this is done via cache warming. If the user clicks the link before the cache is warm, it still waits until the cache is warm, displaying only the loading modal for instance.

It achieves m3avrck's goals, minus the destination part. And thats only because, the get parameters could really determine a different response not just another additional ctools command. Take pagers for example, a ?page=2 will return completely different markup then ?page=4. It would be undesirable to try and determine that at the javascript layer.

But for links like that where you know that on your site user/login/nojs?destination=X, you could write your own behavior for those links and have it the cache warming only once for them. Just requires some creativity.

Small note about my coding style for variables, I use $STRING to represent jQuery objects. if you object to that, then I can rework that. Its just a small short hand I use and I find it helpful.

Does: var $objects = $('a[href=' + old_url + ']') need to refind the same link?

Its not finding the same link. Its finding all links like it (hence plural). So it finds all user/login/nojs?destination=user, and that includes $this, but its also is every other link.

IIRC, jQuery doesn't cache JSON by default

ahh you sure? looking at http://api.jquery.com/jQuery.ajax/, it says "Default true, false for dataType 'script' and 'jsonp'". Now I think that site is for jquery 1.4, so maybe its changed?

Ok I agree with m3avrck that we should add a comment about 'duplicates'. If he couldn't understand what that line was doing and he had explicitly asked for that then clearly it need some comments

added

    // Grab all the links that match this url and add the fetching class.
    // This allows the caching system to grab each url once and only once
    // instead of grabbing the url once per <a>.
   var $objects = $('a[href=' + old_url + ']');

I think that makes it clear.