[wp-hackers] Filter Posts by Custom Taxonomy with AJAX Select Lists

[peter baylies]

Aris,

If all you want to do is cut down on the number of null searches, you might
consider using something like a bloom filter, see here for more info:
http://www.adayinthelifeof.nl/2012/04/09/bloom-filters/

You would want to invalidate / rebuild it on post creation, as well.

Cheers,

 -- Peter

On Thu, Sep 27, 2012 at 8:31 PM, Aris Blevins <aris at goteama.com> wrote:

> I am working on a fairly complicated filtering 'search' page for a site
> that has over 3500 posts and a large, active, user base. This search will
> likely become a primary page for any site user. The site is on a VPS, and
> runs fine, but the owners try and keep their memory needs down to a minimum
> to reduce costs as they are a non-profit.
>
> I have three custom taxonomies: Artists, Years and Genres that are
> associated with the posts. The page displays three multi-select boxes - one
> for each taxonomy. Users can select as many of the terms in each as they
> like, they then click to search and AJAX returns the HTML to the page for
> anything found.
>
> That part works fine. The issue is that there is a high potential for null
> searchs, primarily because of too many terms used. Most of the artists have
> well under 100 posts, whereas years and genres can have a couple hundred at
> most. Selecting an artist and then a year or genre will usually result in a
> a zero set. Having users pound the database for null sets seems foolish.
>
> My hope was that I could have data attributes in the select options - one
> for post counts (already provided in my term objects) and one for the IDs
> of posts in that term. This would serve two purposes:
>
> - As users choose terms I can display how many posts for the taxonomy
> (These artists have 5 posts) Seeing that there is a small set of posts
> would stop users from feeling the need to add a bunch more terms to limit
> the results.
>
> - The IDs could potentially be used to determine if the selected terms
> contain any common posts, if so, how many.
>
> The problem is that the only way I can find to get the ids of the posts in
> a term is by running a new WP_Query for each term. I had hoped to use
> get_objects_in_term but that returns more than posts. It takes quite a
> while to build the page on first load.
>
> My hope is that with caching the page (and all the data) would load
> rapidly, and that some fancy javascript responses will prevent users from
> searching for nulls and keeping my server a bit happier. Is this a good
> trade off? Is there a more efficient way to do this? Is there some other
> approach I am overlooking?
>
> Happy to provide code if needed.
>
> Thanks for any opinions or information.
>
> Aris
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