Struct Client 

pub struct Client<T> { /* private fields */ }

A cache in front of a transport.

Implementations

impl<T: Transport> Client<T>

pub fn new(transport: T, cache: Cache, mode: Mode) -> Self

A client over transport and cache, in mode.

pub fn mode(&self) -> Mode

The mode the client is in.

pub fn fetch( &self, source: &Source, url: &str, now_s: u64, ) -> Result<Fetched, NetError>

The body at url from source, at time now_s (seconds since the Unix epoch).

A cached copy younger than source.ttl_s is returned as Freshness::Cached without a fetch. Otherwise, online, the transport is called and its body cached; if it fails, a stale copy is returned as Freshness::Stale when there is one. Offline, the transport is never called: any cached copy is returned, Freshness::Stale if it is past its TTL.

A copy dated after now_s is never fresh. Online, a cache entry that cannot be read is treated as missing and overwritten by the fetch.

Errors

NetError::NotCached offline with no copy; NetError::Transport online when the fetch fails with no copy; cache errors as Cache::get and Cache::put give them.

pub fn fetch_checked( &self, source: &Source, url: &str, now_s: u64, check: impl Fn(&[u8]) -> Result<(), String>, ) -> Result<Fetched, NetError>

As Client::fetch, but only a body that check accepts is cached or returned: a data source passes its parser, so an answer it can’t read (an error page served as 200, a forecast with its hours still empty) is never kept in place of a good copy.

Online, a fetched body the check refuses is not cached; a stale copy is returned in its place, with the reason, when there is one. A cached copy the check refuses counts as missing online, and is the error offline.

Errors

As Client::fetch, and NetError::Refused when the check refuses the only body there is.

Trait Implementations

impl<T: Debug> Debug for Client<T>

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

Formats the value using the given formatter.