Need help "sanitizing" a custom function that pulls category slug into body class

Question

Not sure if "sanitizing" is really the correct phrase to use for this but it was the best one I could think of...anyways, here is the problem:

My function works great like so...

// add category id to body & post classes 
function category_id_class($classes) {
    global $post;
    foreach((get_the_category($post->ID)) as $category)
        $classes [] = $category->cat_name;
        return $classes;
}
add_filter('post_class', 'category_id_class');
add_filter('body_class', 'category_id_class');

That works great until the user inputs a category such as "Category 1" with a space. Spaces are obviously not desirable as CSS classes so if we could maybe just have a dash added to replace the space that would be perfect - just not sure how to accomplish that?

Thanks!

Answer 1

Just use $category->slug instead of $category->cat_name. Slugs are already lowercase and with dashes instead of spaces.

Answer 2

sanitize_html_class sanitizes a html classname to ensure it only contains valid characters.

foreach((get_the_category($post->ID)) as $category)
    $classes [] = sanitize_html_class($category->cat_name);

Answer 3

sanitize_title_with_dashes should do the trick.

Example:

foreach((get_the_category($post->ID)) as $category)
    $classes [] = sanitize_title_with_dashes($category->cat_name);