Favorites System

favorites.php

<?php 
// Create page in Wordpress called "Favorites"
// Access by calling /favorites?add_favorite=post_id, /favorites?remove_favorite=post_id
// in PHP this would be $link = '/favorites?add_favorite=' . get_the_ID();
//page-favorites.php
if(is_user_logged_in()){
	$favorites = get_user_meta(get_current_user_id(), 'favorites', true);
	if(!empty($_GET['add_favorite'])){
		if(empty($favorites)) $favorites = array();
		$key = array_search($_GET['add_favorite'], $favorites);
		if($key === false){
			array_unshift($favorites, $_GET['add_favorite']);
			update_user_meta(get_current_user_id(), 'favorites', $favorites);
		}
	}
	if(!empty($_GET['remove_favorite'])){
		$key = array_search($_GET['remove_favorite'], $favorites);
		if($key !== false){
			array_splice($favorites, $key);
			update_user_meta(get_current_user_id(), 'favorites', $favorites);
		}
	}
	echo json_encode($favorites);
} else {
	http_response_code(400);
	echo json_encode(array('err' => 'User not logged in'));
}


//Loop for Favorites. Put this in your template file
if(is_user_logged_in()){
	$favorites = get_user_meta(get_current_user_id(), 'favorites', true);
	$favs = new WP_Query(
		array(
			'post_type' => 'post',
			'post_status' > 'publish',
			'posts_per_page' => -1,
			'post__in' => $favorites
		)
	);
	?>

	<?php while($favs->have_posts()): $favs->the_post(); ?>
		<?php the_title(); ?>
		<?php the_content(); ?>
	<?php endwhile; ?>
}