Thread

Moderator’s note: Moved to Howto.

I’m having trouble figuring out how to return an error page if someone tries to access a category that doesn’t exist.
I’m using category names in URLs.
My template is at find/categories.
I’m currently using this code:

{if segment_3==''}
    Code for category list goes here
    {if:elseif segment_3=='category' AND segment_4==''}
    There's no category listed!
    <article>
    {if:elseif segment_3=='category'}
    {exp:channel:entries channel="weblog" limit="30" paginate="bottom" }
        <header class="post-meta directory expand">
            <time datetime="{entry_date format="%Y-%m-%dT%H:%i:%s%Q"}">{entry_date format="%m-%d-%y"}</time>
            <h1><a href="http://{title_permalink=">{title}</a></h1>
        </header>
    {paginate}
        <nav class="pagination">Page {current_page} of {total_pages} pages {pagination_links}</nav>
    {/paginate}
    {/exp:channel:entries}
    </article>
    {if:else}
    {redirect="404"}
    {/if}

So, what’s going on is:

If there’s no segment_3 (which would usually be “category”) I’m going to display a list of categories.

If segment_3 IS there, but no category is requested in segment_4, I’m going to display an error message.

If segment_3 IS there, and a category requested in segment_4, I’m going to display the relevant entries

If there’s some other url structure, I’m redirecting to 404.

That all works, but I can’t figure out how to handle an invalid category request.

Currently, invalid requests (such as “.../category/this-doesnt-exist”) just display all entries.
It seems like I need something like the “no_results” operator, but that won’t work because it’s looking for a URL title, right?

Help?