How to limit top level pages by template

The CMS Questions
1

Say I want to let the user create it’s own customized about page (top level).

blueprints/about.php
templates/about.php

How to limit to 1 about page per site (or level)?
Ideally disable about template from panel once one has been created.

:grin:

2

Useful for single instance templates like: home, error, login, register, about, contact, etc. Typically there’s only one of those per site.

As opposed to multiple instances of: article, event, project, etc.

3

You first have to add the about page:

content/
  about/
    about.txt

On the site.yml blueprint, you can limit the templates the user is allowed to choose from when creating a page.

pages:
  template:
    - default
    - full
    - ...

It is a good practice to specify which templates a parent page accepts, e.g. projects only accepts project template.

4

Thanks, Pedro. IFAIK that will not limit the number of instances of that page, but only which templates allowed.

5

You could achieve this with permissions:

<?php
// site/roles/editor.php
return [
  'name'        => 'Editor',
  'default'     => false,
  'permissions' => [
    '*'                 => true,
    'panel.page.create' => function() {

      if($this->state() === 'ui') {
        // always show the add button
        return true;
      }

      if($this->target()->page()->children()->filterBy('intendedTemplate', '==', 'about')->count() > 0 ) {
        return 'A page with this template already exists';
      }

      return true;

    }
  ]
];

Note that you would need to repeat this for every user role and template.

6

Thank you very much. I’ll give it a try.