Wordpress add rewrite rule doesn't work for me - wordpress

Question

I'm developing a plugin that creates 2 pages: one listing page and one details page.
I don't use custom types. I have created a table into the database where I save the company details and also a slug for the details page.
It's working properly but I have a problem with the URLs. They are not pretty.
On the listing page I use this code to create the link:
<?php echo stripslashes($value->company_name); ?>
The generated link looks like this:
https://www.website.com/company/details/?companyname=new-company-name
I use the query because I need it on the details page, where I use this code:
$company_slug = $_GET['companyname'];
$company_details = $wpdb->get_row("SELECT * FROM $table_company WHERE company_slug = '$company_slug'");
This is how I retrieve the company details from sql and it also works just fine.
I have created manually in Wordpress the details page.
The problem is that I want the details URL to look pretty, like this:
https://www.website.com/company/details/new-company-name/
Generating it like this it's easy but when I click, I get a 404, since the query from URL is missing.
I was thinking it's easy to create directly the pretty URL and on the details page to parse the URL and get the company slug. It didn't work. I get a 404 maybe because the page doesn't physically exist.
So, I've done some research about URL rewrite and I have found some examples but none worked.
I have found tried this code also:
add_filter('query_vars', function($vars) {
$vars[] = "companyname";
return $vars;
});
function custom_rewrite_rule() {
add_rewrite_rule('^companyname/?([^/]*)/?','company/details/?companyname=$matches[1]','top');
}
add_action('init', 'custom_rewrite_rule', 10, 0);
I've read that I shouldn't use matches if I use a custom URL instead of index.php, so I have also tried without matches:
add_rewrite_rule('^companyname/?([^/]*)/?','company/details/?companyname=$1','top');
No results. If course, after every change I have saved again the permalinks.
This should be an easy task but somehow it doesn't work.
https://developer.wordpress.org/reference/functions/add_rewrite_rule/
Does anyone of you know how can I make this work?
Thank you.
Regards,
AG

Answer 1

I am assuming that the details page you created has the slug company/details. Here's what you need to do to make it work-
1. Add the custom rewrite rules in functions.php file:
function theme_custom_rewrites() {
add_rewrite_tag("%companyname%", "([a-z0-9\-_]+)");
add_rewrite_rule('^company/details/([a-z0-9\-_]+)/?$', 'index.php?pagename=company/details&companyname=$matches[1]', 'top');
}
add_action('init', 'theme_custom_rewrites');
It registers a new rewrite tag/query var named companyname to be used later and registers a custom rewrite rule for the specific URL structure you want (/company/details/company_name).
2. Get the company name on the template file and use it: After you have added the above code and saved the permalinks, you can get the companyname just by using the get_query_var() function.
$companyname = get_query_var( 'companyname' );
Hope it helps. Thanks.

Answer 2

Thank you very much for your fast reply. It worked.
Of course, I had to change the link on the listing page to:
<?php echo stripslashes($value->company_name); ?>
I have removed the query from the link and it looks like this now:
https://www.website.com/company/details/new-company-name/
What I don't understand, is how does WP know which is the query, since I removed it from the link.
I can see the same data if I access
https://www.website.com/company/details/?companyname=new-company-name
or
https://www.website.com/company/details/new-company-name/
But, basically, this part (?companyname=) doesn't exist anymore in the link, since I changed it.
I have no query now in my plugin, but somehow everything works properly. :)
I did not declare it somewhere. It's completely gone and it works.
How does this code know that the query exists and it's retrieving the slug from the database?
$companyname = get_query_var( 'companyname' );
I only have this code now:
<?php echo stripslashes($value->company_name); ?>
So, no query in URL.
Thank you for your time.
Regards,
AG