Permission for only one specific page

I have the requirement that there are some users which only have to go to one page in the panel and are allowed to upload images there.
Out of the Permissions-Site it does not work for me. I tried sth like this:

    <?php
    return [
      'name'        => 'Fahrlehrer',
      'default'     => false,
      'permissions' => [
        'panel.file.upload' => function() {
          return $this->target()->page()->template() === 'shop_fahrschueler';
        }
      ]
    ];
    ?>

Try this:

<?php
   return [
     'name'        => 'Fahrlehrer',
     'default'     => false,
     'permissions' => [
       'panel.page.update' => false,
       'panel.page.read' => function() {
         return $this->target()->page()->template() === 'shop_fahrschueler';
       },
       'panel.file.upload' => function() {
         return $this->target()->page()->template() === 'shop_fahrschueler';
       }
     ]
   ];

Than it looks like this:


Could it be a problem that “shop_fahrschueler” is a sub-page of “shop”?
Here the corresponding blueprint of shop:

<?php if(!defined('KIRBY')) exit ?>

title: Shop
pages:
  template:
    - shop_category
    - shop_fahrschueler

Yes, you then have to grant read access to the parent page as well.

Yes now it works with this:

<?php
return [
     'name'        => 'Fahrlehrer',
     'default'     => false,
     'permissions' => [
       'panel.page.update' => false,
       'panel.page.create' => false,
       'panel.page.delete' => false,
       'panel.page.url' => false,
       'panel.page.visibility' => false,
       'panel.page.read' => function() {
         $check = false;
         if($this->target()->page()->template() === 'shop'){
           $check = true;
         } else if($this->target()->page()->template() === 'shop_fahrschueler') {
           $check = true;
         }
         return $check;
       },
       'panel.file.update' => false,
       'panel.file.replace' => false,
       'panel.file.delete' => false,
       'panel.file.upload' => function() {
         return $this->target()->page()->template() === 'shop_fahrschueler';
       }
     ]
   ];
?>

But now I have one thing that is missing. Now the people can still change the template of a page. Is there an option here? Than I think the only thing what they could change is upload files to that specific page!

Managed it like so, think the most smartest way?

<?php
return [
     'name'        => 'Fahrlehrer',
     'default'     => false,
     'permissions' => [
       '*' => false,
       'panel.access' => true,
       'panel.widget.pages' => true,
       'panel.page.read' => function() {
         $check = false;
         if($this->target()->page()->template() === 'shop'){
           $check = true;
         } else if($this->target()->page()->template() === 'shop_fahrschueler') {
           $check = true;
         }
         return $check;
       },
       'panel.file.upload' => function() {
         return $this->target()->page()->template() === 'shop_fahrschueler';
       }
     ]
   ];
?>

This can be shortened anyway and also prohibit changing of templates.

<?php
   return [
     'name'        => 'Fahrlehrer',
     'default'     => false,
     'permissions' => [
       'panel.page.*' => false,
       'panel.page.read' => function() {
         if($this->target()->page()->template() === 'shop' ||  $this->target()->page()->template() === 'shop_fahrschueler') return true;
       },
       'panel.file.upload' => function() {
         return $this->target()->page()->template() === 'blog';
       }
     ]
   ];

(Side note: don’t use a php closing tag in a php-only file)