Changed permalink structure of CPT - should I redirect?

Question

Following this answer, I recently changed the permalink structure of a custom post type called 'Literature' to include the taxonomy term:

Old structure: mysite.com/literature/books/post_name

New structure: mysite.com/literature/fiction/post_name

However, when visiting the original permalink, Wordpress doesn't automatically redirect it and both pages are appearing as separate entries in Google search.

Should I redirect the old literature permalinks? If so, what's the best way to do this?

UPDATE

Thanks Brian, I've amended your code as below and this is working as desired:

add_action('parse_request', 'redirect_books_to_fiction', 0);
function  redirect_books_to_fiction(){
    global $wp;
    if(preg_match('/literature\/books/', $wp->request)){
        $redirect = get_bloginfo('siteurl').'/'.str_replace('books', get_the_term_list( $ID, 'literature_category', '', ' / ', '' ), $wp->request);
        wp_redirect($redirect, 301);
        exit;
    }
}

However, how can I redirect everything and not just 'books'?

On my literature permalinks I can type any word into the trail and it doesn't redirect.

e.g. mysite.com/literature/any_random_word/post_name

Just stays as that permalink.

Whereas, if I visit other pages on my site and change any of the trail leading up to a post, it automatically redirects to the correct permalink.

e.g. If I change: mysite.com/food/recipes/post_name to: mysite.com/a_random_word/another_random_word/post_name

It redirects to the correct permalink.

I assume this is because of the custom permalink structure I used in this answer

Here is the site.

Answer 1

I concur that you need to add a redirect. You can do this easily with the following function. I'm sure you will have to tweak it, but it's a good proof-of-concept.

add_action('parse_request', 'redirect_books_to_fiction', 0);
function  redirect_books_to_fiction(){
    global $wp;
    if(preg_match_all('~literature\/(.+)/(.+)?~', $wp->request, $matches)){
        $redirect = get_bloginfo('siteurl').'/'.str_replace('books', 'fiction', $wp->request);
        wp_redirect($redirect, 301);
        exit;
    }
}

To further answer you question regarding matching segments:

add_action('parse_request', 'redirect_cpts', 0);
function  redirect_cpts(){
    $one_to_one = array(
        'literature' => 'books',
        'food' => 'foo',
        'bar' => 'food'
    );
    $request = $_SERVER['REQUEST_URI'];

    //We limit the scope of the regex to our specified CPTs so we don't hammer every request
    if(preg_match_all('~(literature|food|bar)/(.+)/(.+)?~', $request, $matches)){
        if(!$one_to_one[$matches[1][0]])
            return;

        $post_type = $one_to_one[$matches[1][0]]; //Do proper escaping
        $post_name = $matches[3][0]; //Do proper escaping

        if($post_name && $post_type){
            global $wpdb;
            $post = $wpdb->get_row("SELECT * ID FROM $wpdb->posts WHERE post_type = '$post_type' AND post_name = '$post_name'");
            $redirect = get_permalink($post);
            if($redirect){
                wp_redirect($redirect, 301);
                exit;
            }
        }
    }
}

Answer 2

I would also recommend looking at the plugin Redirection as a good way to manage your changed urls / permalinks