Taxonomy based permalinks

Question

With my website I work with my own taxonomy. And I want that the taxonomy is intergrated with the permalink. So if an news page has a taxonomy, the permalink change.

Like this: mysite.com/%custom_tax%/blog/%postname% And if it's a page this: mysite.com/%custom_tax%/%postname%

But if there is no taxonomy I want: mysite.com/blog/%postname% And if it is an page: mysite.com/%postname%

How can I easily do this?

I already set up the %custom_tax% :

add_filter('post_link', 'custom_tax_permalink', 10, 3);
add_filter('post_type_link', 'custom_tax_permalink', 10, 3);


function custom_tax_permalink($permalink, $post_id, $leavename) {
    if (strpos($permalink, '%custom_tax%') === FALSE) return $permalink;

    // Get post
    $post = get_post($post_id);
    if (!$post) return $permalink;

    // Get taxonomy terms
    $terms = wp_get_object_terms($post->ID, 'custom_tax');  
    if (!is_wp_error($terms) && !empty($terms) && is_object($terms[0])) $taxonomy_slug = $terms[0]->slug;
    else $taxonomy_slug = '';


    flush_rewrite_rules();
    return str_replace('%custom_tax%', $taxonomy_slug, $permalink);
}

Answer 1

Try something like this:

function custom_rewrite( $wp_rewrite ) {

    $feed_rules = array(
        '(.+)/blog/(.+)'      =>  'index.php?custom_tax='.$wp_rewrite->preg_index(1).'&post_name=' . $wp_rewrite->preg_index(2)
    );

    // ( array merge must be done this way, to ensure new rule comes first )
    $wp_rewrite->rules = $feed_rules + $wp_rewrite->rules;
}
// refresh/flush permalinks in the dashboard if this is changed in any way
add_filter( 'generate_rewrite_rules', 'custom_rewrite' );

Remember to flush permalinks by visiting the permalinks page and re-saving if you add/change this code. Also remove the flush_rewrite_rules(); as advised by Stephen, it's unnecessary and bad practice.