I am trying to debug 'undefined index' errors on the WP backend when debug is set to TRUE. The offending lines are:

if ( !wp_verify_nonce( $_POST['pdwt_meta_noncename'], plugin_basename(__FILE__) )) {
    return $post->ID;

Which I have then changed to check whether the value has been set by adding:

if ( isset( $_POST['pdwt_meta_noncename']) || ! wp_verify_nonce( $_POST['pdwt_meta_noncename'], plugin_basename(__FILE__) )) {
    return $post->ID;

The addition makes the error disappear but when I enter information on the custom field, it does not save.

This is how the custom field has been set:

echo '<input type="hidden" name="pdwt_meta_noncename" id="pdwt_meta_noncename" value="' .
    wp_create_nonce( plugin_basename(__FILE__) ) . '" />';

Here is the save_post part:

foreach ($pdwt_meta as $key => $value) { // loop through the $pdwt_meta array
    if( $post->post_type == 'revision' ) return; // make sure the data isn't stored twice
    $value = implode(',', (array)$value); // if $value is in an array, make it a comma seperated value
    if(get_post_meta($post->ID, $key, FALSE)) { // if the custom field already has a value
        update_post_meta($post->ID, $key, $value);
        add_post_meta($post->ID, $key, $value);
    if(!$value) delete_post_meta($post->ID, $key); // DELETE IF IT'S EMPTY
add_action('save_post', 'pdwt_save_meta', 1, 2); // SAVE THE CUSTOM FIELDS 

I did not write this specific part of the theme. Any thoughts on what could be wrong?

  • I'm also having the same problem. Till can't find any solution. For the volunteers, here's the exact tuts link that the process is revised: code.tutsplus.com/articles/… Oct 15, 2014 at 4:19
  • 1
    @mayeenul Ah! thanks for this! Have you tried applying the solution suggested on the comments on this tutorial. It looks like I was missing a line on the save_post part by the look of it for this line: wp_nonce_field( basename( __FILE__ ), 'custom_meta_box_nonce' ); In function save_meta() replace this line: if (!wp_verify_nonce($_POST['custom_meta_box_nonce'], basename(__FILE__))) for this line: if (!isset($_POST['custom_meta_box_nonce']) || !wp_verify_nonce($_POST['custom_meta_box_nonce'], basename(__FILE__)))
    – nivims
    Nov 21, 2014 at 16:55
  • it worked. You can add this as answer mentioning the comment as a link with a basic explanation, and then can accept it as an answer. It'll help others. :) Feb 10, 2015 at 9:57
  • Great you got it working @MayeenulIslam. Have now added it as an answer. Cheers!
    – nivims
    Feb 11, 2015 at 15:58

1 Answer 1


Resolved by following comment on Tutsplus Tutorial (link included):

In function save_meta(), replace this line:

if (!wp_verify_nonce($_POST['custom_meta_box_nonce'], basename(__FILE__)))

with this line:

if (!isset($_POST['custom_meta_box_nonce']) || !wp_verify_nonce($_POST['custom_meta_box_nonce'], basename(__FILE__)))

See full comment here.

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