Random Alphanumeric Key URLs

Question

I need random (and unique) alphanumeric permalinks. I've looked at several plugins but they all seem to do some form of redirection to a longer URL. That's not what I want, I want the permalink to be changed.

Basically, I'm wanting URLs like bit.ly or 9gag.com.

I've looked, but came up empty in my searches - does a plugin exist that does this? If not, could someone point me into the right direction as to how I might accomplish it? I'm pretty self sufficient in PHP but I'm not very familiar with WordPress yet.

The easiest way I could think of is something like add_filter("post_slug", md5(rand())) (if that were actually valid code). Obviously, I'd have to check for duplicate slugs and what not...

Honestly, what I'd much rather prefer is something like: example.com/prefix/hf434g5ay/postname In that the /prefix/alphanumeric-key is required but postname is used for SEO.

Answer 1

If you'd like to keep your slugs for SEO, then you'll want to define a new rewrite tag and leave the default behavior for post slugs.

If you'd like a unique id, then instead of looking up possible duplicates, why not just re-use the post ID which is guaranteed to be unique given a MySQL primary index – you can convert it to a base36 number if you want it to look more like bitly.

add_action( 'init', function() {
    add_rewrite_tag( '%my_id%', '([a-z0-9]+)' );
});

add_action( 'pre_get_posts', function( $query ) {
    if ( ! $query->is_main_query() || is_admin() )
        return;

    $id = $query->get( 'my_id' );
    if ( ! empty( $id ) ) {
        $query->set( 'p', base_convert( $id, 36, 10 ) );
        $query->set( 'name', null );
    }
});

add_filter( 'post_link', function( $permalink, $post ) {
    $id = base_convert( $post->ID, 10, 36 );
    return str_replace( '%my_id%', $id, $permalink );
}, 10, 2 );

Then change your permalinks structure to /%my_id%/%postname%/ in Settings - Permalinks. If you want more than 0-9 and lowercase characters, you can look for some base 62 implementations, though I'm not a big fan of case-sensitive URLs.

Hope that helps.

Answer 2

To append a random slug to a post using something like:

add_filter( 'wp_unique_post_slug', 'unique_slug_108286', 10, 4 );

function unique_slug_108286( $slug) {    
    $slug = mt_rand(); //just an example
    return $slug;
}

I'm pretty sure WP will handle duplicates using this filter (it does by default) so you do not need to check for them yourself.

You can add a prefix manually in your permalinks admin setting by setting it to something like /prefix/%postname%/

It might be better to use a category or custom taxonomy for the prefix. As for setting the random slug before the postname like prefix/hf434g5ay/postname I think it would require using the http://codex.wordpress.org/Rewrite_API , it would be easier to create a custom post type to do this instead of mangling the default "posts".