public function onWpLoaded()
    {
        if ($this->c::isCli()) {
            return; // Not applicable.
        } elseif (empty($_REQUEST[$this->var])) {
            return; // Not applicable.
        }
        $this->action = (string) $_REQUEST[$this->var];
        $this->action = $this->c::unslash($this->action);
        $this->action = $this->c::mbTrim($this->action);

        $this->c::noCacheFlags(); // Flag as do NOT cache.
        $this->c::noCacheHeaders(); // Send headers also.

        if ($this->viaAjax($this->action)) {
            header('content-type: application/json; charset=utf-8');
            $this->c::isAjax(true);
        } elseif ($this->viaApi($this->action)) {
            header('content-type: application/json; charset=utf-8');
            $this->api_version = $this->parseApiVersion($this->action);
            $this->action      = $this->stripApiVersion($this->action);
            $this->c::isApi(true);
        }
        $this->c::doingRestAction($this->action); // w/o API version.

        if (!isset($this->registered_actions[$this->action])) {
            $this->s::dieInvalid(); // Unregistered!
        }
        $actor = $this->registered_actions[$this->action];

        if ($actor['requires_valid_nonce']) {
            $this->s::requireValidNonce($this->action);
        }
        $Utility = $this->App->Utils->{$actor['class']};
        $Utility->{$actor['method']}($this->action);
    }