Ticket #32965: attachment-credit_v0-2.php

<?php
/*
Plugin Name: Attachment Credit Field
Description: Adds a credit field to the attachment details pane to add attribution information.
Version:     0.2
Author:      Michael V Cuomo
Author URI:  http://www.michaelvcuomo.com
License:     GPL2
License URI: https://www.gnu.org/licenses/gpl-2.0.html
*/

/* Start adding functions below this line */

/*
 * Notes:
 * 
 * This plugin was developed as a test to see how to add a credit field to the attachment page. While it
 * does work, there are some differences between this field and the "standard" fields. Namely, this returns
 * the credit field as part of a table, while the others are being returned as a label with CSS classes. This
 * therefore is affecting CSS styles in some areas, like the attachment editor page. Also, looking through 
 * the media.php file shows there is a lot more going on with current attachment details, like returning shortcodes
 * for the caption--img_caption_shortcode()-- and such. I am not that experienced with working with WordPress code
 * so I'm not sure how much I can help. Anyone with more experience might be better, or this might want to be included
 * in the current code, like in the array in get_attachment_fields_to_edit().
 *
 * I haven't yet been able to figure out how to display this in my theme. I currently am using the caption field for
 * image attribution for Featured Images and display it using:
 *      echo '<cite class="feat-image-caption">' . get_post(get_post_thumbnail_id())->post_excerpt . '</cite>';
 * It is not working by adding post-credit, though. Just keep that in mind -- I'll still mess around and update
 * if I find a solution.
 *
 */

function mvc_add_attachment_credit_field( $form_fields, $post ) {
    // See wp-admin/includes/media.php function get_attachment_fields_to_edit() line 1164
    //
    // Add new form field to attachment details page called Credit.
    // Credit field allows users to add attribution information to media files.
    
    $field_value = get_post_meta( $post->ID, 'post-credit', true );
    
    $form_fields['post-credit'] = array(
        'label' => __( 'Credit' ),
        'input' => 'textarea',
        'value' => $field_value ? $field_value : '',
        //'helps' => __( 'Information to credit the source of this uploaded file.' )
    );
    
    return $form_fields;
}

// Attach function to hook
add_filter( 'attachment_fields_to_edit', 'mvc_add_attachment_credit_field', 10, 2 );

// Save Credit field
function mvc_save_attachment_credit( $attachment_id ) {
    
    if ( isset( $_REQUEST['attachments'][$attachment_id]['post-credit'] ) ) {
        
        $credit = $_REQUEST['attachments'][$attachment_id]['post-credit'];
        
        update_post_meta( $attachment_id, 'post-credit', $credit );
    }
}
// Attach function to hook -- THIS ONE DOES WORK
add_action( 'edit_attachment', 'mvc_save_attachment_credit' );

// Original - Attach function to hook -- THIS ONE NOT WORKING FOR ME - won't save info
//add_filter ( 'attachment_fields_to_save','mvc_save_attachment_credit' );

/* Stop adding functions below this line */

?>