WordPress的URL到HTML

I'm trying to ajaxify wordpress the clean way. The idea is this:

1. Ajax request is made from client to ajax action url (for example /wp/wp-admin/admin-ajax.php?action=my_plugin_fetch_page&page=http://example.com/about).
2. Response of that request should be in JSON format and contain at least page title and content of page (equivalent to http://example.com/about).

I cannot figure out a good way to get contents of page by only knowing its url.

I have tried using wp_remote_get. So I simply make another request from server to url http://example.com/about. This works, but it's quite slow (slowing down a request about 2 seconds).

I have tried using url_to_postid, which converts url to post_id. Unfortunately this does not work for archive pages and probably would be useless anyways, since I need full response body from url http://example.com/about, not just id of the equivalent page.

This is how it works currently with wp_remote_get:

function my_plugin_fetch_page () {

    /*
     *
     * Getting url of target page from GET parameters
     *
     */
    $url = $_GET['page'];

    $title = '';
    $content = '';

    /*
     *
     * Url must be set in request parameters and it must be internal link
     *
     */
    if ( $url && my_plugin_is_internal_page( $url ) ) {

        /*
         *
         * Format relative urls to absolute urls.
         *
         * test/example -> http://example.com/test/example
         *
         */
        $url = nolife_single_format_url( $url );

        /*
         *
         * Make GET request.
         *
         */
        $page_response = wp_remote_get( $url, array(
            'user-agent'  => 'InternalRequester'
        ) );

        if ( ! is_wp_error( $page_response ) ) {

            /*
             *
             * Response contains title and page content seperated by some
             * seperator. By splitting response from that seperator, we
             * get title and contents of page in seperate values.
             *
             */
            $content_parts = explode( MY_PLUGIN_SEPERATOR, wp_remote_retrieve_body( $page_response ) );

            // title comes first
            $title = $content_parts[0];

            // then content of page
            $content = $content_parts[1];
        }
    }

    wp_send_json( array(
        'url'      => $url,
        'title'    => $title,
        'content'  => $content
    ) );

    die;
}

Can anyone please help me with this one?

This snippet checks to see if a string exists in any defined taxonomy, including custom ones:

$term = "maybe_a_term";
$taxonomies = get_taxonomies(['show_ui' => true]);
$term_exists = array_reduce($taxonomies, function($carry, $item) use ($term) {
  return $carry || get_term_by('slug', $term, $item);
}, false);

The $taxonomies array is reduced to a boolean, so $term_exists will be true if the term is found. You could then use a taxonomy-based query to gather the posts you need.

Note: The argumement ['show_ui' => true] hides internal taxonomies like post_format and nav_menu.

It's insane that WordPress can't reverse-parse its own permalinks.