functions.php

<?php

add_action( 'init', function() {
	add_theme_support( 'align-wide' );
	show_admin_bar( true );
	
	add_action( 'wp_enqueue_scripts', function() {
		wp_enqueue_script('postbox',admin_url("js/postbox.min.js"),array( 'jquery-ui-sortable' ),false, 1 );
		wp_enqueue_style('dashicons');
		wp_enqueue_style('common');
		wp_enqueue_style('forms');
		wp_enqueue_style('dashboard');
		wp_enqueue_style('media');
		wp_enqueue_style('admin-menu');
		wp_enqueue_style('admin-bar');
		wp_enqueue_style('nav-menus');
		wp_enqueue_style('l10n');
		wp_enqueue_style('buttons');
		wp_enqueue_style('frontenberg', get_template_directory_uri() . '/style.css');
	} );
	add_action( 'wp_enqueue_scripts', 'gutenberg_editor_scripts_and_styles' );

	if ( ! is_user_logged_in() ) {
		add_filter( 'wp_insert_post_empty_content', '__return_true', PHP_INT_MAX -1, 2 );
		add_filter( 'pre_insert_term', function( $t ) {return ''; });
	}
});

add_action( 'after_setup_theme', 'register_my_menu' );
function register_my_menu() {
	register_nav_menu( 'sidebar', __( 'Side Menu', 'frontenberg' ) );
}

// Disable use XML-RPC
add_filter( 'xmlrpc_enabled', '__return_false' );

// Disable X-Pingback to header
add_filter( 'wp_headers', 'disable_x_pingback' );
function disable_x_pingback( $headers ) {
	unset( $headers['X-Pingback'] );

	return $headers;
}

function frontenberg_give_permissions( $allcaps, $cap, $args ) {
	if ( is_user_logged_in() ) {
		return $allcaps;
	}
	// give author some permissions
	$allcaps['read'] = true;
	$allcaps['manage_categories'] = false;
	$allcaps['edit_post'] = true;
	$allcaps['edit_posts'] = true;
	$allcaps['edit_others_posts'] = true;
	$allcaps['edit_published_posts'] = true;

	// better safe than sorry
	$allcaps['edit_pages'] = false;
	$allcaps['switch_themes'] = false;
	$allcaps['edit_themes'] = false;
	$allcaps['edit_pages'] = false;
	$allcaps['activate_plugins'] = false;
	$allcaps['edit_plugins'] = false;
	$allcaps['edit_users'] = false;
	$allcaps['import'] = false;
	$allcaps['unfiltered_html'] = false;
	$allcaps['edit_plugins'] = false;
	$allcaps['unfiltered_upload'] = false;

	return $allcaps;
}
add_filter( 'user_has_cap', 'frontenberg_give_permissions', 10, 3 );

function frontenberg_remove_toolbar_node($wp_admin_bar) {
	if ( is_user_logged_in() ) {
		return;
	}
	// replace 'updraft_admin_node' with your node id
	$wp_admin_bar->remove_node('wpseo-menu');
	$wp_admin_bar->remove_node('new-content');
	$wp_admin_bar->remove_node('comments');
	$wp_admin_bar->remove_node('wp-logo');
	$wp_admin_bar->remove_node('bar-about');
	$wp_admin_bar->remove_node('search');
	$wp_admin_bar->remove_node('wp-logo-external');
	$wp_admin_bar->remove_node('about');
	$wp_admin_bar->add_menu( array(
		'id'    => 'wp-logo',
		'title' => '<span class="ab-icon"></span>',
		'href'  => home_url(),
        'meta'  => array(
			'class' => 'wp-logo',
			'title' => __('FrontenBerg'),            
		),
	));
	$wp_admin_bar->add_menu( array(
		'id'    => 'frontenderg',
		'title' => 'Frontenberg',
		'href'  => home_url(),
		'meta'  => array(
			'title' => __('FrontenBerg'),            
        ),
    ));
	
}
add_action('admin_bar_menu', 'frontenberg_remove_toolbar_node', 999);

add_action( 'wp_ajax_nopriv_query-attachments', 'frontenberg_wp_ajax_nopriv_query_attachments' );
/**
 * Ajax handler for querying attachments.
 *
 * @since 3.5.0
 */
function frontenberg_wp_ajax_nopriv_query_attachments() {
	$query = isset( $_REQUEST['query'] ) ? (array) $_REQUEST['query'] : array();
	$keys = array(
		's', 'order', 'orderby', 'posts_per_page', 'paged', 'post_mime_type',
		'post_parent', 'post__in', 'post__not_in', 'year', 'monthnum'
	);
	foreach ( get_taxonomies_for_attachments( 'objects' ) as $t ) {
		if ( $t->query_var && isset( $query[ $t->query_var ] ) ) {
			$keys[] = $t->query_var;
		}
	}

	$query = array_intersect_key( $query, array_flip( $keys ) );
	$query['post_type'] = 'attachment';
	if ( MEDIA_TRASH
		&& ! empty( $_REQUEST['query']['post_status'] )
		&& 'trash' === $_REQUEST['query']['post_status'] ) {
		$query['post_status'] = 'trash';
	} else {
		$query['post_status'] = 'inherit';
	}

	// Filter query clauses to include filenames.
	if ( isset( $query['s'] ) ) {
		add_filter( 'posts_clauses', '_filter_query_attachment_filenames' );
	}

	/**
	 * Filters the arguments passed to WP_Query during an Ajax
	 * call for querying attachments.
	 *
	 * @since 3.7.0
	 *
	 * @see WP_Query::parse_query()
	 *
	 * @param array $query An array of query variables.
	 */
	$query = apply_filters( 'ajax_query_attachments_args', $query );
	$query = new WP_Query( $query );

	$posts = array_map( 'wp_prepare_attachment_for_js', $query->posts );
	$posts = array_filter( $posts );

	wp_send_json_success( $posts );
}

/**
 * Trying to make changes on the server won't work, so why bother contacting the REST API anyway?
 * This function hooks into the apiFetch and adds a middleware. This middleware intercepts all
 * PATCH PUT DELETE etc requests and replaces them with "empty promises" that resolve immediatley
 * without consequence.
 *
 * Sure, the requests would fail anyway, but this way there's fewer pings to the server to deal
 * with, and failure is now instantaneous*/
add_action( 'wp_footer', function() {
	?>
	<script>
	// @TODO: This setTimeout hack doesn't sit well with me, find a better solution that doesn't require jQuery
	setTimeout( function() {
		window._wpLoadGutenbergEditor.then( function( editor ) { 
			wp.apiFetch.use( function ( options, next ) {
				if ( 'method' in options ) {
					if ( [ 'PATCH', 'PUT', 'DELETE' ].indexOf( options.method.toUpperCase() ) >= 0 ) {
					        return new Promise(function(resolve, reject) {
							// Save Data
							resolve(data);
						});
					}
				}
				const result = next( options );
		    		return result;
			} );
		} );
	}, 500 );
	</script>
	<?php
});

add_filter( 'update_post_metadata', function(  $check, $object_id, $meta_key ) {
	if ( $meta_key == '_edit_lock' ) {
		return false;
	}
	return $check;
}, 10, 3 );