How can I get the meta description of a post?

[slim16165]

Hi,
I'm currently using the WordPressPCL library to interact with my WordPress site's REST API. I'm able to retrieve posts successfully, but I'm having trouble accessing the meta description of these posts.

I understand that the Post class in WordPressPCL has a Meta property, which (I think) should contain the post's custom fields. In my WordPress setup, I'm using the Yoast SEO plugin, which stores the meta description in a custom field named _yoast_wpseo_metadesc.

Here's the code I'm using to retrieve a post:

var client = new WordPressClient("http://mysite.com/wp-json");
var post = await client.Posts.GetByID(1);
var metaDescription = post.Meta["_yoast_wpseo_metadesc"];

However, this doesn't seem to work. The Meta property doesn't appear.

I've read that the WordPress REST API doesn't include custom fields by default, and I tried to follow a tutorial which suggested to implement:

 add_action('rest_api_init', 'register_rest_meta_desc');

function register_rest_meta_desc() {
    register_rest_field('post',
        '_yoast_wpseo_metadesc',
        array(
            'get_callback'    => 'get_meta_desc',
            'update_callback' => null,
            'schema'          => null,
        )
    );
}

function get_meta_desc($object, $field_name, $request) {
    return get_post_meta($object['id'], $field_name, true);
}

Could anyone provide some guidance? Any help would be greatly appreciated

[slim16165]

I've solved adding this code:

function my_register_rest_field() {
    register_rest_field( 'post', '_yoast_wpseo_metadesc', array(
        'get_callback' => 'my_get_custom_field',
        'update_callback' => 'my_update_custom_field',
        'schema' => array(
            'description' => 'Yoast SEO meta description',
            'type' => 'string',
        ),
    ) );
}
add_action( 'rest_api_init', 'my_register_rest_field' );

function my_get_custom_field( $object, $field_name, $request ) {
    return get_post_meta( $object['id'], $field_name, true );
}

function my_update_custom_field( $value, $object, $field_name ) {
    update_post_meta( $object->ID, $field_name, $value );
}


function my_register_meta() {
    register_meta( 'post', '_yoast_wpseo_metadesc', array(
        'show_in_rest' => true,
        'single' => true,
        'type' => 'string',
    ) );
}
add_action( 'init', 'my_register_meta' );

The c# code to access the field is:

public static class PostExtensions
{
    public static string GetMetaDescription(this Post post)
    {
        return post.Meta.ContainsKey("_yoast_wpseo_metadesc") ? post.Meta["_yoast_wpseo_metadesc"] : null;
    }
    public static bool IsMetaDescriptionEmpty(this Post post)
    {
        return string.IsNullOrEmpty(post.GetMetaDescription());
    }
}