Last Updated: February 25, 2016
· acefxlabs

Using Ajax in Wordpress for external script

Probably this is one of my biggest headaches. I have a project to deliver and i was using wordpress for development and speed.
After almost enjoying the good sail the big issue struck.
When i send data through AJAX to a PHP file that i wrote, the PHP get the message but my AJAX somehow keeps getting 404 response and when i check my console, its clear PHP replied.

Ok i did alot of tweaks and nothing worked and decided to search google which went for hours.
Lucky me i found the solution and i believe its important to share it here.

This is a post response by Tim Stone (a big thanks man) and i am not editing it but putting it up word for word.

When you include wp-blog-header.php, you end up bootstrapping the whole WordPress setup routine. The function wp() is called, which calls $wp->main(), which in turn calls various setup functions.

One of these is $wp->query_posts(), which calls $wp_the_query->query(), which in turn calls WPQuery's ``` parsequery()function. I suspect that the 404 indication is generated in there (your AJAX page isn't a WP post, or anything like that), and is later transformed into an actual 404 response header by $wp->handle404(), the function called afterqueryposts()``` in main().

I'm not 100% sure that parse_query() is the definite culprit, but I would suggest seeing if you can just include wp-load.php instead, since I believe it does the actual work of creating the objects that you want to access.

Again, I don't actually use WordPress, so I can't be sure, but looking at the source code this seems to be the most likely case, from what I can tell.

2 Responses
Add your response

over 1 year ago ·

You have two ways to get around that:
- Include the correct file :) When you don't want to parse the request via WordPress' main query(like when handling AJAX via a php file), include the wp-load.php file
- Even better - send your AJAX to /wp-admin/admin-ajax.php with at least an "action" parameter.
Then in your plugin/theme you have to add(if your action parameter is "myaction")

add_action( 'wp_ajax_myaction', 'myaction_function_callback' );

Note that the above will only work for requests from logged-in users. To add support for non-logged-in users add this:

add_action( 'wp_ajax_nopriv_myaction', 'myaction_function_callback' );

myaction_function_callback should be an existing function(you can use any "callback" parameter - like array( $myobject, 'callback' ) ).
Once you're done with processing the AJAX request don't forget to do exit() or die() so that WordPress doesn't print '0' at the end of your output.

over 1 year ago ·