I have a JS file that triggers a PHP callback file. The PHP file is supposed to work on the Post that is currently opened (wp-admin/post.php). I do not want the JS file to pass the post id though since that could be tampered with.

Is there any way to repopulate the global $post or set up the callback appropriately?

JS trigger:

        type: 'POST',
        url: js_vars.ajaxurl,
        data: {
            action: 'my_action_key'

PHP Callback:

add_action('wp_ajax_sometest', function () {
    $post_id = get_the_ID();
    echo $post_id; // does not print id

It's possible to capture the $post_id using a combination of wp_get_referer() and url_to_postid() then reset the $post using setup_postdata.

That should work easy enough for the front-end. But on the admin side we'll need to pull the query with parse_url and grab the ID using parse_str. For good measure we should double check if we're editing a post by checking the action and also see if the ID is_numeric -- running intval before we use it to rule out any funny business.


// for logged-in users
add_action( 'wp_ajax_foobar', 'wpse20160117_wp_ajax_foobar' );

// let's skip the nopriv because we want to only target logged-in users
// add_action( 'wp_ajax_nopriv_foobar', 'wpse20160117_wp_ajax_foobar' );

function wpse20160117_wp_ajax_foobar() {

    $url     = wp_get_referer();

    $post_id = '';

    // works with front-end urls
    // $post_id = url_to_postid( $url );

    if ( empty( $post_id ) ) { // lets do it the hard way

        // strip the query
        $query = parse_url( $url, PHP_URL_QUERY );

        // parse the query args
        $args  = array();
        parse_str( $query, $args );

        // make sure we are editing a post and that post ID is an INT
        if ( isset( $args[ 'post' ] ) && is_numeric( $args[ 'post' ] ) && isset( $args[ 'action' ] ) && $args [ 'action' ] === 'edit' ) {

            if ( $id = intval( $args[ 'post' ] ) ) {

                // cool.. it worked
                $post_id = $id;

    if ( ! $post_id ) {
        echo "No foobar for you!";
    } else {
        global $post;

        // make sure we have a post
        if ( $post = get_post( $post_id ) ) {

            // prep the post data
            setup_postdata( $post );

            // now we're ready!
            echo "Are you referring to $post_id? Title: " . get_the_title();

        } else {
            echo "No post for you!";


        'action': 'foobar',
        'data':   'baz'
        alert('The server responded: ' + response);
| improve this answer | |
  • This approach sounds really promising. url_to_postid only seems to work when given a frontend-permalink though - is there a similar method for the admin panel? (the url in my case would be e.g. http://localhost/wordpress/test/wp-admin/post.php?post=553&action=edit) – mschrimpf Jan 18 '16 at 10:06
  • Modified it slightly to only work with logged-in users and on the back-end. You can still uncomment the sections to work with the front-end. – jgraup Jan 18 '16 at 20:21
  • Is there any need to use nonces with this approach, i.e. is the wp_get_referer method safe? – mschrimpf Jan 21 '16 at 0:17
  • Yes, you should be passing nonces to tie the action to a specific logged In user for a short amount of time. – jgraup Jan 21 '16 at 0:38

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