WordPress Ajax Problems

Question

Update

I got it to fire using the following curl command: curl -H "Accept: application/json" -X POST http://localhost/wordpress/wp-admin/admin-ajax.php -d "action=vixo_wordpress_signon&data=banjometer" --trace -

Not really sure how to work out to get it to accept json, but hey...

Original Question

I am new to WordPress and I am having problems getting Ajax to work - but I am also having problems understanding how WordPress loads PHP.

I have a plugin file:

/usr/share/wordpress/wp-content/plugins/myplugin.php

It has the following code in it:

// set up the ajax calls
add_action('wp_ajax_my_ajax', 'my_ajax');
add_action('wp_ajax_nopriv_my_ajax', 'my_ajax');  

function my_ajax () {
    debug_log ("My ajax fired...");
    echo "banjolalia...";
    die ();
}

I want to demonstrate that the ajax has fired using Curl:

curl -X POST http://localhost/wordpress/wp-admin/admin-ajax.php -d '{"action":"my_ajax","data":"banjometer"}' --trace -

(The home page is at http://localhost/wordpress)

I am expecting to see curl return banjolalia and a line appear in the debug log.

What I see is the function returns 0

The Ajax is standalone because I am writing single-signon code and I need the child service to query WordPress and see if the user is logged in.

Because I am new to WordPress/PHP I do not have a robust development cycle.

The way I have been (trying) to get the code to reload is by Deactivating/Activating the plugin on the Admin page. This doesn't seem to work. I wasn't sure if my changes were loading into WordPress so I actually switched the lappie off and on again - but still the Ajax didnt' fire.

I have 2 debugging Plugins installed:

• Debug-Bar
• Debug-Console-Bar

The problems I have from a Dev perspective are:

• how can I use the PHP console to check what code is loaded/force a reload?
• how can I use the PHP console to see what actions are registed on what hooks?

Answer 1

You have nothing specific to do to "load" modified php code in Wordpress. All files are just loaded as is at execution time (ie when the HTTP request is processed by the server). You just have to verify that your plugin is active.

Your curl command is malformed. Use this instead :

curl -X POST http://localhost/wordpress/wp-admin/admin-ajax.php -d action=my_ajax -d data=banjometer --trace -

But CURL is not really the easiest debug tool to use. When I need a fast and easy way to execute some debug php code inside Wordpress, I use the plugin activation hook :

<?php

register_activation_hook(__FILE__, 'my_plugin_debug'); 
function my_plugin_debug() {

    $log = 'banjometer';

    die("OK, $log");
}

?>

Make a new plugin that contains only this code, then try to activate it in the backend. You will get an error (because of the die statement) so the plugin will not be activated, but your code will be run and you can see the log in the error message.

Answer 2

I don't know anything about CURL, but looking at admin-ajax.php you get a 0 either at the beginning because no action is set, or at the end of the file because it couldn't find a matching action. Perhaps you are executing your CURL command too early? Ie, before the ajax callbacks have a chance to be recognized? If you're on a local install, you could tweak the error codes in admin-ajax.php to at least tell you at which point it is failing. Just don't forget to put it back or you'll pull your hair out later. (Have done)

Just noticed the similar questions in the sidebar and I suspect this is the answer: http://wordpress.stackexchange.com/a/70407/6477

Edit The codex confirms that plugin files are run before the wp_ajax_ hook so how about trying running your code at a later action?

function wpa82473(){
  curl -X POST http://localhost/wordpress/wp-admin/admin-ajax.php -d '{"action":"my_ajax","data":"banjometer"}' --trace -
}
add_action('init', 'wpa82473');