context['postId'] ) ) {
return '';
}
if ( post_password_required( $block->context['postId'] ) ) {
return;
}
$footnotes = get_post_meta( $block->context['postId'], 'footnotes', true );
if ( ! $footnotes ) {
return;
}
$footnotes = json_decode( $footnotes, true );
if ( count( $footnotes ) === 0 ) {
return '';
}
$wrapper_attributes = get_block_wrapper_attributes();
$block_content = '';
foreach ( $footnotes as $footnote ) {
$block_content .= sprintf(
'%2$s ↩︎',
$footnote['id'],
$footnote['content']
);
}
return sprintf(
'%2$s
',
$wrapper_attributes,
$block_content
);
}
/**
* Registers the `core/footnotes` block on the server.
*
* @since 6.3.0
*/
function register_block_core_footnotes() {
foreach ( array( 'post', 'page' ) as $post_type ) {
register_post_meta(
$post_type,
'footnotes',
array(
'show_in_rest' => true,
'single' => true,
'type' => 'string',
)
);
}
register_block_type_from_metadata(
__DIR__ . '/footnotes',
array(
'render_callback' => 'render_block_core_footnotes',
)
);
}
add_action( 'init', 'register_block_core_footnotes' );
/**
* Saves the footnotes meta value to the revision.
*
* @since 6.3.0
*
* @param int $revision_id The revision ID.
*/
function wp_save_footnotes_meta( $revision_id ) {
$post_id = wp_is_post_revision( $revision_id );
if ( $post_id ) {
$footnotes = get_post_meta( $post_id, 'footnotes', true );
if ( $footnotes ) {
// Can't use update_post_meta() because it doesn't allow revisions.
update_metadata( 'post', $revision_id, 'footnotes', $footnotes );
}
}
}
add_action( 'wp_after_insert_post', 'wp_save_footnotes_meta' );
/**
* Keeps track of the revision ID for "rest_after_insert_{$post_type}".
*
* @since 6.3.0
*
* @global int $wp_temporary_footnote_revision_id The footnote revision ID.
*
* @param int $revision_id The revision ID.
*/
function wp_keep_footnotes_revision_id( $revision_id ) {
global $wp_temporary_footnote_revision_id;
$wp_temporary_footnote_revision_id = $revision_id;
}
add_action( '_wp_put_post_revision', 'wp_keep_footnotes_revision_id' );
/**
* This is a specific fix for the REST API. The REST API doesn't update
* the post and post meta in one go (through `meta_input`). While it
* does fix the `wp_after_insert_post` hook to be called correctly after
* updating meta, it does NOT fix hooks such as post_updated and
* save_post, which are normally also fired after post meta is updated
* in `wp_insert_post()`. Unfortunately, `wp_save_post_revision` is
* added to the `post_updated` action, which means the meta is not
* available at the time, so we have to add it afterwards through the
* `"rest_after_insert_{$post_type}"` action.
*
* @since 6.3.0
*
* @global int $wp_temporary_footnote_revision_id The footnote revision ID.
*
* @param WP_Post $post The post object.
*/
function wp_add_footnotes_revisions_to_post_meta( $post ) {
global $wp_temporary_footnote_revision_id;
if ( $wp_temporary_footnote_revision_id ) {
$revision = get_post( $wp_temporary_footnote_revision_id );
if ( ! $revision ) {
return;
}
$post_id = $revision->post_parent;
// Just making sure we're updating the right revision.
if ( $post->ID === $post_id ) {
$footnotes = get_post_meta( $post_id, 'footnotes', true );
if ( $footnotes ) {
// Can't use update_post_meta() because it doesn't allow revisions.
update_metadata( 'post', $wp_temporary_footnote_revision_id, 'footnotes', $footnotes );
}
}
}
}
foreach ( array( 'post', 'page' ) as $post_type ) {
add_action( "rest_after_insert_{$post_type}", 'wp_add_footnotes_revisions_to_post_meta' );
}
/**
* Restores the footnotes meta value from the revision.
*
* @since 6.3.0
*
* @param int $post_id The post ID.
* @param int $revision_id The revision ID.
*/
function wp_restore_footnotes_from_revision( $post_id, $revision_id ) {
$footnotes = get_post_meta( $revision_id, 'footnotes', true );
if ( $footnotes ) {
update_post_meta( $post_id, 'footnotes', $footnotes );
} else {
delete_post_meta( $post_id, 'footnotes' );
}
}
add_action( 'wp_restore_post_revision', 'wp_restore_footnotes_from_revision', 10, 2 );
/**
* Adds the footnotes field to the revision.
*
* @since 6.3.0
*
* @param array $fields The revision fields.
* @return array The revision fields.
*/
function wp_add_footnotes_to_revision( $fields ) {
$fields['footnotes'] = __( 'Footnotes' );
return $fields;
}
add_filter( '_wp_post_revision_fields', 'wp_add_footnotes_to_revision' );
/**
* Gets the footnotes field from the revision.
*
* @since 6.3.0
*
* @param string $revision_field The field value, but $revision->$field
* (footnotes) does not exist.
* @param string $field The field name, in this case "footnotes".
* @param object $revision The revision object to compare against.
* @return string The field value.
*/
function wp_get_footnotes_from_revision( $revision_field, $field, $revision ) {
return get_metadata( 'post', $revision->ID, $field, true );
}
add_filter( 'wp_post_revision_field_footnotes', 'wp_get_footnotes_from_revision', 10, 3 );