How to add_rewrite_rule with two parameters to a single view page?

Question

I'm having troubles understanding how add_rewrite_rule works in my case. I have a page which lists news from an external source. All items are linked with a "read more". Those links look like: domain.com/news/single/?id=12345&title=title-of-this-news

Everything works fine. If I click the link the "single" page reads the "id" param and displays the output I want it to.

Well to make this pretty I want the links to look like this: domain.com/news/12345/title-of-this-news which means /single/ not part of the url - the first part is the ID I need to fetch it's data and the title the last part.

Can someone help me with this? Thanks!

EDIT: due to one of the answers I came up with this to match my URL, params, and so on - but it is not working (permalinks are resaved):

// Register the custom rewrite rule.
function wpse_373628_init() {
    add_rewrite_rule(
        // Matches /news/<id>/<title-slug> in the URL.
        '^news-events/single/(\d+)/([^/]+)/?$',

        // You could also add &news_title=$matches[2], but I think the ID is
        // enough for you to identify the single news being requested.
        'index.php?pagename=news-events/single&newsID=$matches[1]&newsTitle=$matches[2]', // query by slug
//      'index.php?page_id=123&news_id=$matches[1]',          // or query by ID

        'top'
    );
}
add_action( 'init', 'wpse_373628_init' );

// And register the custom query arg.
function wpse_373628_query_vars( $vars ) {
    $vars[] = 'newsID';
    $vars[] = 'newsTitle'; // if you're using news_title in the rewrite rule
    return $vars;
}
add_filter( 'query_vars', 'wpse_373628_query_vars' );

Answer 1

If you haven't already done so, I suggest you to check out this Codex article which gives a good introduction on how you can use add_rewrite_rule() to rewrite a URL in WordPress.

Now if the news and single are Pages (i.e. posts of the page type) and that single is a child of the news Page, then in the second parameter for add_rewrite_rule() (i.e. the redirect URL), you would want to use pagename=news/single which will load the single Page.

Alternatively, you can use page_id=<ID> to query the Page by its ID instead.

See the WP_Query class for more details regarding pagename and page_id.

Then you would also want to use a custom query arg for the single news ID because for example you wouldn't be able to retrieve the ID using $_GET['id']. And then you should add the custom arg to the public query args which WordPress reads from the URL and pass them to WP_Query.

So having said that, try the following:

// Register the custom rewrite rule.
function wpse_373628_init() {
    add_rewrite_rule(
        // Matches /news/<id>/<title-slug> in the URL.
        '^news/(\d+)/([^/]+)/?$',

        // You could also add &news_title=$matches[2], but I think the ID is
        // enough for you to identify the single news being requested.
        'index.php?pagename=news/single&news_id=$matches[1]', // query by slug
//      'index.php?page_id=123&news_id=$matches[1]',          // or query by ID

        'top'
    );
}
add_action( 'init', 'wpse_373628_init' );

// And register the custom query arg.
function wpse_373628_query_vars( $vars ) {
    $vars[] = 'news_id';
//  $vars[] = 'news_title'; // if you're using news_title in the rewrite rule
    return $vars;
}
add_filter( 'query_vars', 'wpse_373628_query_vars' );

And be sure to flush the rewrite rules by simply visiting the permalink settings page (wp-admin » Permalink Settings) so that WordPress recognizes the new rewrite rule (above) and saves it in the database.

And also, to retrieve the news ID, you can use get_query_var( 'news_id' ).