Struct Object 

pub struct Object<T, F, E = ()>
where
    F: AsyncFnMut() -> Result<T, E>,
{ /* 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, E> Object<T, F, E>

where F: AsyncFnMut() -> Result<T, E>,

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

Create a new cached Object with default value specify in second argument. ttl is “time to live” which is duration that the cached value will be return. refresh_fn is a function to refresh value and last update time.

pub async fn new_and_refresh( ttl: Duration, refresh_fn: F, ) -> Result<Object<T, F, E>, E>

Create a new cached Object and immediately refresh the value instead of using default value. ttl is “time to live” which is duration that the cached value will be return. 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<(), E>

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, E>

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

pub fn time_remain(&self) -> Duration

Get time remain that the cache still valid. In other word, time remain before it return TimeoutError on Object::get function.

Trait Implementations

impl<T, F, E> CachedObject<T, E> for Object<T, F, E>

where F: AsyncFnMut() -> Result<T, E>,

fn refresh(&mut self) -> Pin<Box<dyn Future<Output = Result<(), E>> + '_>>

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

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

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

fn get_or_refresh<'a>( &'a mut self, ) -> Pin<Box<dyn Future<Output = Result<&'a T, E>> + 'a>>

where T: 'a,

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

fn time_remain(&self) -> Duration

Get time remain that the cache still valid. In other word, time remain before it return TimeoutError on Object::get function.

impl<T: Clone, F, E: Clone> Clone for Object<T, F, E>

where F: AsyncFnMut() -> Result<T, E> + Clone,

fn clone(&self) -> Object<T, F, E>

Returns a duplicate of the value.

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

Performs copy-assignment from source.

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

where T: Debug, F: AsyncFnMut() -> Result<T, E>,

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

Formats the value using the given formatter.

impl<T: Copy, F, E: Copy> Copy for Object<T, F, E>

where F: AsyncFnMut() -> Result<T, E> + Copy,