John Davidson

Message:

I've created a custom meta box, but i can't update that through api rest. This is my code. The var $_POST in a function save_custom_meta_box is always empty when I send a request.

Create meta box

add_action( 'add_meta_boxes', 'adding_custom_meta_boxes', 10, 2 );

if (!function_exists('adding_custom_meta_boxes')) {

    function adding_custom_meta_boxes( $post_type, $post ) {

        add_meta_box(

            "demo-meta-box",

            "Custom Meta Box",

            "custom_meta_box_markup",

            "post",

            "side",

            "high",

            null

        );

    }

}

Storing Meta Data

add_action("save_post", "save_custom_meta_box", 10, 3);

function save_custom_meta_box($post_id, $post, $update)

{

    if(!current_user_can("edit_post", $post_id)){

        return $post_id;

    }



    if($post->post_type != "post"){

        return $post_id;

    }



    $meta_box_checkbox_value = "";



    if(isset($_POST["meta-box-checkbox"]))

    {

        $meta_box_checkbox_value = $_POST["meta-box-checkbox"];

    }



    update_post_meta($post_id, "meta-box-checkbox", $meta_box_checkbox_value);

}

SOLUTION:
Use action rest_after_insert_post.

add_action('rest_after_insert_post', 'wp_kama_rest_after_insert_post_type_action', 10, 3);

function wp_kama_rest_after_insert_post_type_action( $post, $request, $creating ) {



    if ($creating) {

        return;

    }

    

    $body = json_decode($request->get_body());

    if($body->metaBoxCheckbox)

    {

        update_post_meta($post->ID, "meta-box-checkbox", $body->metaBoxCheckbox);

    }



    return;

}

---

My Answer:
'custom_meta_box', // ID of the meta box
'Custom Meta Box', // Title of the meta box
'display_custom_meta_box', // Callback function to display the meta box
$post_type, // Post type where the meta box should be displayed
'normal', // Context of the meta box (e.g., 'normal', 'side', 'advanced')
'high' // Priority of the meta box (e.g., 'high', 'core', 'default', 'low')
);
}
}

function display_custom_meta_box( $post ) {
$custom_meta_value = get_post_meta( $post->ID, 'custom_meta_key', true );
?>
Custom Meta Field:

}

function save_custom_meta_box( $post_id ) {
if ( isset( $_POST['custom_meta_field'] ) ) {
update_post_meta( $post_id, 'custom_meta_key', sanitize_text_field( $_POST['custom_meta_field'] ) );
}
}

add_action( 'save_post', 'save_custom_meta_box' );

In your REST API request, make sure you are sending the custom_meta_field parameter in the request body. For example, if you are using the fetch API in JavaScript:

fetch('https://example.com/wp-json/wp/v2/posts/123', {
method: 'POST',
headers: {
'Content-Type': 'application/json',
'X-WP-Nonce': wpApiSettings.nonce
},
body: JSON.stringify({
custom_meta_field: 'Updated value'
})
});

This should update the custom meta box value when you send a request to the WordPress REST API.