Add Post Meta Fields via WP API v2 - wordpress

Question

I'm trying to play with the WP API v2 and insert posts from Postman.
If I post this raw request, it creates a post just fine:
{
"title": "Test Title",
"content": "Test Content",
}
However, I'm trying to add some custom field values to this as well, and I can't seem to get them to work. This request creates a post, but doesn't add any meta fields:
{
"title": "Test Title",
"content": "Test Content",
"meta": {
"foo": "bar",
"foo2": "bar2"
}
}
How do I POST the meta fields foo and foo2 with the values bar and bar2 through the API endpoint https://my-site.com/wp-json/wp/v2/posts?
Edit: It also appears custom fields don't get pulled natively in GET requests. I put this code in a mu-plugin:
add_filter( 'rest_prepare_post', 'xhynk_api_post_meta', 10, 3 );
function xhynk_api_post_meta( $data, $post, $context ){
$meta = get_post_custom( $post->ID );
if( $meta ) {
$data->data['meta'] = $meta;
}
return $data;
}
Which at least lets me view it on a GET request. However I still can't seem to get it to POST via Postman. Even adding "status": "publish" will cause the new post to publish instead of being a draft like it is by default. Are there any hooks or filters I can use on API POST requests to make sure the custom fields are added?

Answer 1

to handle metas on insertion and update, you can do it with action rest_insert_ + post type
add_action("rest_insert_page", function (\WP_Post $post, $request, $creating) {
$metas = $request->get_param("meta");
if (is_array($metas)) {
foreach ($metas as $name => $value) {
update_post_meta($post->ID, $name, $value);
}
}
}, 10, 3);