Struct Object

pub struct Object<T, F>
where
    F: AsyncFn() -> Result<T, Box<dyn Error>>,
{ /* private fields */ }

Generic cache object which cache an object for given period of time before it return TimeoutError to signal caller to call refresh function before further attempt. The refresh_fn should be async function that return Result of the same type as the cached object. If there’s any error occur inside refresh_fn, it should return Error result back.

Implementations

impl<T, F> Object<T, F>

where F: AsyncFn() -> Result<T, Box<dyn Error>>,

pub fn new(ttl: u128, obj: T, refresh_fn: F) -> Object<T, F>

Create a new cached Object with default value specify in second argument. ttl is in milli-second unit. refresh_fn is a function to refresh value and last update time.

pub async fn new_and_refresh( ttl: u128, refresh_fn: F, ) -> Result<Object<T, F>, Box<dyn Error>>

Create a new cached Object and immediately refresh the value instead of using default value. ttl is in milli-second unit. refresh_fn is a function to refresh value and last update time. The different from new function is that it is async and it immediately call refresh_fn.

pub async fn refresh(&mut self) -> Result<(), Box<dyn Error>>

Refresh cache immediately and update last update time if refresh success.

pub fn get(&self) -> Result<&T, TimeoutError>

Read current cached value or return Error if cache is already expired.

pub async fn get_or_refresh(&mut self) -> Result<&T, Box<dyn Error>>

Read current cached value or refresh the value if it is already expired then return the new value.

Trait Implementations

impl<T, F> Debug for Object<T, F>

where T: Debug, F: AsyncFn() -> Result<T, Box<dyn Error>>,

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

Formats the value using the given formatter.