WP gives 404 error for custom post type with GET variable

Question

I use the following method to add a $_GET Variable to my custom post type in wordpress.

 add_filter('query_vars', 'add_type2_var', 0, 1);

function add_type2_var($vars){ $vars[] = 'type2'; return $vars; }

add_rewrite_rule('/?c/(.[^/])/(.[^/])/(.*)$',"/c/$1/$2?type2=$3",'top');

My custom post type is non-hierarchical post. The links to the posts works without a problem but when I try to add something at the end after the slash the links stop working.

If I add show at the end of http://127.0.0.1/wp/c/default/dd http://127.0.0.1/wp/c/default/dd/show the link gives a 404 error. Though it works perfectly fine when I add numbers at the end like http://127.0.0.1/wp/c/default/dd/123456 and I could also get the 123456 using $_GET in php.

I am not sure where the problem is but my guess is that wordpress gives an 404 error before my function. I have a function using single_template filter.

UPDATE:

I have added a function to `template_redirect.

function CPTTest() 
{
    if ( is_singular('cpt') ) 
    {
       echo 'cpt';
    }
    elseif ( is_singular() ) {
       echo 'post';
    }
    else
    {
        echo 'none';
    }
    var_dump($_GET);
    die();
}

This works fine when I use the url http://127.0.0.1/wp/c/default/dd/show. Only problem is that it doesn't recognize it as a cpt post. But it does recognize http://127.0.0.1/wp/c/default/dd/123456 as a cpt post. Same result when I used wp action instead of template_redirect.

Answer 1

Numbers work because single posts can have pagination, and there is a rewrite rule to support that.

If you want to add an additional parameter after a permalink, add a rewrite endpoint.

add_rewrite_endpoint( 'show', EP_PERMALINK );

EDIT- Here's an internal rewrite example, assuming your custom post type slug is type1:

add_rewrite_rule(
    'c/([^/]+)/([^/]+)/([^/]+)/?$',
    'index.php?type1=$matches[1]&type2=$matches[3]',
    'top'
);

Answer 2

It gives you 404 by a fact that there is nothing found on your request. I guess it's because type is registered query_var. You can try to debug this situation with plugins: debug-bar (tab "Request") and debug-bar-rewrite-rules (Rewrite Rules).