Template change permissions

Kirby 2 Solved ✅
1

Can you somehow prevent users from changing a specific template to another one using permissions or a hook?

So a permission like that: (pseudo code)

'panel.page.update' => function() {
  
  if ($this->old()->page()->intendedTemplate() == "text" AND $this->target()->page()->intendedTemplate() == "images") {
    return false;
  }
  else {
    return false;
  }
  
}

Or a hook like that:

kirby()->hook('panel.page.update', function($page, $oldPage) {
  if ($oldPage->intendedTemplate() == "text" AND $page->intendedTemplate == "images") {
    // Do something.
  }
});

It seems like there is no way to check what the old value was, neither with permissions nor with a hook. Or am I missing something?

2

The hook knows the old page object, but a hook won’t work because hooks are only triggered AFTER an event has happened, so the only thing you could do via a hook is change the template back to the original again, but by then it might be too late.

As regards permissions, I doubt that this is possible, because there is not old page object.

Your best bet is probably to change your content structure in a way as to only allow certain templates via the parent page.

3

Thanks for your quick answer!

Are you sure the hook has access to the old page object before the update? For me $oldPage->template() and $page->template() return the exact same thing. There is an $oldPage argument in the docs for panel.page.update after all. But it only seems to work with panel.page.move for me.

I don’t think it would be “too late” to change the template back again as the content stays the same.

4

Unless there is some sort of bug (need to check that), the old page object is available since 2.3.2.

Edit: Well, the hook works as expected for content changes, but it seems that the template or intended template is not taken into account, even though the hook is triggered.

Edit2: Maybe we should create a feature request on GitHub for both storing all page data in the old page object as well as for more specific permissions.

As a workaround, I just had the idea to save the template name in a hidden field in the text file and then compare the template name against the field value on panel.page.update.

5

Thank you for checking! That indeed seems like the best workaround.

I will add an issue on GitHub, anyway. I think the $oldPage should contain all the information $page contains.