Struct Can 

#[non_exhaustive]
pub struct Can<T> {
    pub item: T,
    pub abilities: BTreeMap<String, bool>,
}

A model together with what the current user may do with it, so templates can ask the policy: {% if can('update', product) %}.

async fn index(State(db): State<Db>, user: Option<AuthUser>, Page(page): Page) -> Result<View> {
    let products = Product::query().paginate(&db, page, 20).await?
        .map(|p| Can::new(p, user.as_deref(), &["update", "delete"]));
    Ok(view("products/index.html", context! { products }))
}

It serializes as the model’s own fields plus _can ({"update": true, …}); guests get false for every ability.

Fields (Non-exhaustive)

Non-exhaustive structs could have additional fields added in future. Therefore, non-exhaustive structs cannot be constructed in external crates using the traditional Struct { .. } syntax; cannot be matched against without a wildcard ..; and struct update syntax will not work.

item: T

The model, serialized as its own fields.

abilities: BTreeMap<String, bool>

Each asked ability and whether it is allowed, serialized as _can.

Implementations

impl<T: Policy> Can<T>

pub fn new<V: Viewer + ?Sized>( item: T, user: Option<&V>, abilities: &[&str], ) -> Self

Asks item’s policy about each of abilities; a guest (None) gets false for all.

Trait Implementations

impl<T: Clone> Clone for Can<T>

fn clone(&self) -> Self

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl<T: Debug> Debug for Can<T>

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl<T> Serialize for Can<T>

where T: Serialize,

fn serialize<__S>(&self, __serializer: __S) -> Result<__S::Ok, __S::Error>

where __S: Serializer,

Serialize this value into the given Serde serializer.