6. Protected fields

The price is the shop's to set and the accountant's to read. A manager reads the order and never the price; a customer never writes it.

Protecting a field

In the model, beside its permissions:

permissions = build_permissions(
    'order',
    _('orders'),
    protected_fields=('price',),
)

That adds two permissions: shop.order_view_price and shop.order_edit_price. Or with no code, Access, Protected fields, the model, Protect:

The primary key cannot be protected: it is how a row is found.

What it changes

A field the person may not read is left out of every door - the API, Django's forms and templates, the admin site's forms, lists, search, filters and ordering, and rules. The accountant holds order_view_price; the managers do not. The same order, opened by north_manager, has no price:

A field they may read and not write is shown and locked. A write that names it - "price": "1.00" sent to the API by a customer - is a 400 naming the field, not a silent drop.

In code

from clearance.fields import readable_fields, writable_fields

readable_fields(user, Order)   # {'id', 'customer', 'branch', 'item', 'status'}
writable_fields(user, Order)