add_rewrite_rule not working with custom variables

Question

I posted this in stackoverflow as well, so hope it's good to post here as well!

I think this is my last problem to solve before everything clicks into place:

I have a homepage with a custom plugin that sends some data to another page, I am building a theme for this website that works with the plugin.

So in the theme functions.php I have added a

function myvar($vars){
    $vars[] = 'ep_year';
    $vars[] = 'ep_name';
    return $vars;
}
add_filter('query_vars','myvar');

works a charm, I can send those values over to a custom page with a custom template assigned. This has a permalink as follows:

http://ngofwp.local/episode/

and when I send the data over it looks like so (permalinks are enabled):

http://ngofwp.local/episode/?ep_year=2011&ep_name=silly_donkey

I know I have to use an add_rewrite_rule so I've started coding that as follows:

function custom_rewrite_rule()
    {
        add_rewrite_rule('^episode/([^/]*)/([^/]*)\.html$','?ep_year=$matches[1]&ep_name=$matches[2]','top');
    }
add_action('init', 'custom_rewrite_rule');

But now for the life of me I have no clue about the formulae to get it to work. I have read the regex rules and tested that particular rewrite on a site that helps you do that.

What I'd like it to look like is this:

http://ngofwp.local/episode/2011/silly_donkey.html

The

http://ngofwp.local/episode/

is given by wordpress's permalink setting and is a custom page in the templates folder (it displays correctly)

What did I do wrong?

Answer 1

It looks like your add_rewrite_rule function is not quite correct. The first parameter should be the regular expression pattern that you want to match, and the second parameter should be the query string that you want to rewrite the URL to. Also, you don't need to include the file extension in the URL.

Try updating your custom_rewrite_rule function to this:

function custom_rewrite_rule() {
    add_rewrite_rule('^episode/([^/]*)/([^/]*)/?$','index.php?page_id=PAGE_ID&ep_year=$matches[1]&ep_name=$matches[2]','top');
}
add_action('init', 'custom_rewrite_rule');

Replace PAGE_ID with the ID of the page that displays the custom template for your /episode/ URL. You can find the page ID by editing the page in WordPress and looking at the URL in your browser's address bar - it will be something like post.php?post=PAGE_ID&action=edit.

This rule will match a URL like http://ngofwp.local/episode/2011/silly_donkey/ and rewrite it to http://ngofwp.local/index.php?page_id=PAGE_ID&ep_year=2011&ep_name=silly_donkey.

After updating the functions.php file, you'll need to go to the WordPress dashboard Settings > Permalinks and click the "Save Changes" button to flush the rewrite rules cache and make your new rule active.

Answer 2

What I suspect has happened is that you're using this to hide the ugly URL variables and turn them into pretty URLs via regex, and you've almost done that part correctly:

?ep_year=$matches[1]&ep_name=$matches[2]

But nothing in that tells WordPress which page you wanted. How is it meant to know it should be the episode page?

To fix this it will need to explicitly tell WP this, perhaps with something like this:

?ep_year=$matches[1]&ep_name=$matches[2]&pagename=episode

Then on top of that, the regex maps to the wrong URL, ugly permalinks always take the form index.php followed by URL parameters. This is the reason why WP rewrite rules can't map URLs on to arbitrary files. So it needs to instead map to:

index.php?ep_year=$matches[1]&ep_name=$matches[2]&pagename=episode

The other issue it will have is that because it uses a custom page template the header tags will be set up for a singular piece of content, not an archive. This also means WP might decide to redirect to what it thinks is the canonical URL, and it also means everything under /episode has the canonical URL or /episode, which is true and correct. You might have intended this to be an archive of episodes with individual episodes accessible via a rewrite, but you've only built the appearance of such an archive. It will need to filter these to fix that.

To truly do this correctly though, it needs a CPT for each episode, custom permalinks, and a filter to modify each episodes post URL to add the correct year.

Note that for any of this to work:

• pretty permalinks have to be enabled in settings
• you have to flush permalinks/rewrite rules whenever you change the rewrite rules, visiting the permalinks settings page is enough to do this
• use get_query_var not $_GET in your template
• your URL must match the regex, it should show as a match in WP debugging plugins too