<?php
/**
* WPSEO plugin file.
*
* @package WPSEO
*/
/**
* WPSEO_Custom_Fields.
*/
class WPSEO_Custom_Fields {
/**
* Custom fields cache.
*
* @var array|null
*/
protected static $custom_fields = null;
/**
* Retrieves the custom field names as an array.
*
* @link WordPress core: wp-admin/includes/template.php. Reused query from it.
*
* @return array The custom fields.
*/
public static function get_custom_fields() {
global $wpdb;
// Use cached value if available.
if ( self::$custom_fields !== null ) {
return self::$custom_fields;
}
self::$custom_fields = [];
/**
* Filters the number of custom fields to retrieve for the drop-down
* in the Custom Fields meta box.
*
* @param int $limit Number of custom fields to retrieve. Default 30.
*/
$limit = apply_filters( 'postmeta_form_limit', 30 );
$sql = "SELECT DISTINCT meta_key
FROM $wpdb->postmeta
WHERE meta_key NOT BETWEEN '_' AND '_z' AND SUBSTRING(meta_key, 1, 1) != '_'
LIMIT %d";
$fields = $wpdb->get_col( $wpdb->prepare( $sql, $limit ) );
/**
* Filters the custom fields that are auto-completed and replaced as replacement variables
* in the meta box and sidebar.
*
* @param string[] $fields The custom field names.
*/
$fields = apply_filters( 'wpseo_replacement_variables_custom_fields', $fields );
if ( is_array( $fields ) ) {
self::$custom_fields = array_map( [ 'WPSEO_Custom_Fields', 'add_custom_field_prefix' ], $fields );
}
return self::$custom_fields;
}
/**
* Adds the cf_ prefix to a field.
*
* @param string $field The field to prefix.
*
* @return string The prefixed field.
*/
private static function add_custom_field_prefix( $field ) {
return 'cf_' . $field;
}
}
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