Can a component view be configured to show a only a subset of available User Groups when adding it to a menu?
My component has a front-end view that must never be allowed to be viewed by anyone except users which are within a custom front-end User Group. I understand that the person adding the menu item should "know" what they're doing, but I'm interested to know if this can be done as well.
Not in a standard sense, i.e. the normal UI provided by Joomla. (Presuming you're talking about when an actual menu item is created here?) Extensions don't get a chance to run code when a menu item is created so, short answer: no.
I would normally suggest a plug-in but looking at com_menu I can only see two JEventDispatcher calls and they aren't very useful.
In /administrator/components/com_menus/models/menutypes.php you have:
// Allow a system plugin to insert dynamic menu types to the list shown in menus:
JEventDispatcher::getInstance()->trigger('onAfterGetMenuTypeOptions', array(&$list, $this));
And in /administrator/components/com_menus/views/items/view.html.php you have:
// Allow a system plugin to insert dynamic menu types to the list shown in menus:
JEventDispatcher::getInstance()->trigger('onBeforeRenderMenuItems', array($this));
Looking a layer deeper, the menu item class MenusModelItem extends JModelAdmin the good thing here is that JModelAdmin does trigger an onContentChangeState() event which you could trap and dis-allow anyone try to set your view to published if the user group is wrong.
Having said that, I wouldn't be doing that. Menu's are just paths and easy to guess in our SEO/SEF world. The right place to do it is in the component/view itself, rejecting anyone that isn't in the right group. You can do this either silently bouncing users back to the home page or throw a 404.
