Post Meta

Custom Field containers are used to extend the post edit screens with additional fields. Field data is stored separately for each post as post meta (see add_post_meta).

Visibility options

Custom fields containers are very flexible in terms of display options. You can select specific post type they show on, as well as category, format, parent, etc. A list of all options is displayed below:

Post type

->show_on_post_type('page')

You can also show a single container on multiple post types, as seen below:

->show_on_post_type(array('page', 'my_custom_post_type', 'post'))

Categories and custom taxonomies

Containers may be assigned to posts from specific categories or taxonomies:

->show_on_category($category_slug)

->show_on_taxonomy_term($term_slug, $taxonomy)

Pages and subpages

Show container on a specific page, identified by path or ID, for example: "parent-page/sub-page":

->show_on_page($page_path|$page_id)

Show container on all subpages of a specific page, identified by path, for example: "parent-page":

->show_on_page_children($parent_page_path)

Page templates

Containers may be assigned to pages using specific template:

->show_on_template($template_path)

The $template_path is the name of the template file (or array of template file names), for example: "about_us.php" or array("templates/contact.php", "about_us.php")

You can also hide the container from pages using specific template:

->hide_on_template($template_path)

where the $template_path is the name of the template file (or array of template file names), as in show_on_template() above.

Post formats

To display a container on posts with specific post format, use:

->show_on_post_format($post_format)

Level

To display a container on hierarchical posts from a specific level, use:

->show_on_level($level)

where $level is the level of hierarchy depth, starting from 1 and increasing when going into further hierarchy depth.

Container position

More information about the position options can be found in the add_meta_box() function.

Context

The part of the page where the container should be shown ('normal' (default), 'advanced', or 'side')

->set_context('normal')

Priority

The priority within the context where the container should show ('high' (default), 'core', 'default' or 'low')

->set_priority('high')

Accessing field values

To access field values you need to use the function carbon_get_post_meta($id, $name, $type = null), where:

Parameter	Description
$id	Post ID where your value was entered.
$name	The name of the field to be retrieved.
$type (optional)	If the field you want to retrieve is of type complex, you need to pass "complex".

<!-- Simple field -->
<p>Article was published in: <?php echo carbon_get_post_meta(get_the_ID(), 'crb_location'); ?></p>

<!-- Complex field -->
<?php 
$slides = carbon_get_post_meta(get_the_ID(), 'crb_slides', 'complex');
if ( $slides ) {
    foreach ($slides as $slide) {
        echo $slide['image'];
    }
}
?>

You can also use carbon_get_the_post_meta($name, $type = null) to access the values for the current post in The Loop.

<p>Article was published in: <?php echo carbon_get_the_post_meta('crb_location'); ?></p>

<?php $slides = carbon_get_the_post_meta('crb_slides', 'complex'); ?>

After saving, the carbon_after_save_post_meta hook is called, which allows you to hook additional functionality after saving. It accepts the $post_id parameter, which is the ID of the post being updated. Example:

add_action('carbon_after_save_post_meta', 'crb_after_save_event');
function crb_after_save_event($post_id) {
    if ( get_post_type($post_id) !== 'crb_event' ) {
        return false;
    }

    $event_date = carbon_get_post_meta($post_id, 'crb_event_date');
    if ( $event_date ) {
        $timestamp = strtotime($event_date);
        update_post_meta($post_id, '_crb_event_timestamp', $timestamp);
    }
}