Need to use a simple WordPress loop via Ajax? You can use the following code to do just that using built-in functionality.
/**
* Show a single post via admin-ajax.php
*
* Use a url like this to call this function:
* /wp-admin/admin-ajax.php?action=mfields_show_post&p=514
*
* @since 2010-12-04
*/
function mfields_ajax_show_post() {
$id = ( isset( $_GET['p'] ) ) ? (int) $_GET['p'] : false;
query_posts( array( 'p' => $id ) );
if ( have_posts() ) {
while( have_posts() ) {
the_post();
the_title();
the_content();
comments_template( '', true );
}
}
else {
print '<p>No posts</p>';
}
exit;
}
add_action( 'wp_ajax_mfields_show_post', 'mfields_ajax_show_post' );
add_action( 'wp_ajax_nopriv_mfields_show_post', 'mfields_ajax_show_post' );
Interesting idea but I am not sure why you would want to use admin-ajax.php instead of the init hook on the site url (ie website.com/?params-here)? Is there some benefit to it?
Maybe it doesn’t do all the initialization stuff that is required on a normal site load, in which case I guess it would be faster.
I started using Ajax with WordPress in the Administration Panels and this is the way that I learned to create a callback + I always like to hook into the appropriate place. This being said, I rarely hook into
initanymore as there always seems to be a more appropriate place.Using the ajax hooks allows me to easily see and understand the intentions I had when creating my functions. If they are hooked into
wp_ajax, I immediately know that I intended to create an ajax callback for administration purposes. In cases where a function is hooked into bothwp_ajaxandwp_ajaxnoprivI know that I intended the function to be used as a public resource that both visitors and logged-in users can access.I really don’t know if admin-ajax.php loads any less of WordPress than would be included before init.
That’s really interesting, I don’t really know about either of these things. I’ve been thinking about it though and I think I will have to stick with the init hook for my themes. The reason is that I create premium themes so I don’t know who will use them or how.
In turn this means that I don’t know what the wordpress setup is for different users, but I do know that often restricting access to the wp-admin directory is encouraged in security posts (generally through IP/ htpassword restrictions) so relying on the wp-admin directory for something public won’t work.
Very good point, but it is far from a deal breaker when it comes to using admin-ajax.php for public resources IMHO. I just found this article via the codex page titled Hardening WordPress which offers examples of how to allow admin-ajax.php to function while requiring authentication for others.
I might add that before I posted this I asked the following question on Twitter: “Is it bad to use init to process Ajax on the front-end of WordPress?”. Within minutes I received 3 responses, from developers I trust, that admin-ajax.php using the
noprivhook was the way to go. I really don’t know if there’s anything wrong with usinginit– honestly, I don’t think there is, nor am I trying to dissuade you from using it. I just posted this code for reference and hopefully to help those who might need a quick copy-and-paste to get started on their own projects.I totally understand where you are coming from with this. I am just trying to expand my knowledge. Like you, I don’t think there’s any one right or wrong way to go about things. I am always learning and through conversing and learning more perhaps I can improve my products a little bit.
I am going to have a read of those links – thanks for the info! :)