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Right now for my plugin, I am using in_admin() to determine if the user is in the frontend of the site or in the admin area. However, the problem occurs when plugins use admin_ajax.php to process ajax requests.

I need a way to register hooks and plugins only when processing admin_ajax.php or in the frontend of the site. What is the best way to go about doing that?

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1 Answer 1

up vote 14 down vote accepted

Check the constant DOING_AJAX. Its definition is the first working code in wp-admin/admin-ajax.php.


if ( defined( 'DOING_AJAX' ) && DOING_AJAX )
    // do something
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if ( defined( 'DOING_AJAX' ) ) is enough by itself. The constant is only set in admin-ajax.php so you don't need to check for a value. –  John Reid Nov 26 '14 at 13:55
@JohnReid It is a global constant, anyone can set it to any value, including FALSE. –  toscho Nov 26 '14 at 16:36
Good point. There's nowhere in the WP core that sets this value but I suppose that it doesn't mean that some rogue plugin might not set it to false instead. A +1 for you, sir! –  John Reid Dec 1 '14 at 10:32

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