Struct Write

pub struct Write<P: Key> { /* private fields */ }

Middleware for data that persists between Requests for data which mostly needs to be written instead of read.

The data is stored behind a Mutex, so only one request at a time can access the data. This is more performant than State in the case where most uses of the data require a write lock.

Write can be linked as BeforeMiddleware to add data to the Request extensions and it can be linked as an AfterMiddleware to add data to the Response extensions.

Write also implements Plugin, so the data stored within can be accessed through request.get::<Write<P>>() as an Arc<Mutex<P::Value>>.

Implementations

impl<P: Key> Write<P>

where P::Value: Send,

pub fn both<T>(start: T) -> (Write<P>, Write<P>)

where T: PersistentInto<Arc<Mutex<P::Value>>>,

Construct a new pair of Write that can be passed directly to Chain::link.

The data is initialized with the passed-in value.

Examples found in repository

examples/hitcounter.rs (line 25)

fn main() {
    let mut chain = Chain::new(serve_hits);
    chain.link(Write::<HitCounter>::both(0));
    Iron::new(chain).http("localhost:3000").unwrap();
}

pub fn one<T>(start: T) -> Write<P>

where T: PersistentInto<Arc<Mutex<P::Value>>>,

Construct a new Write that can be passed directly to Chain::link_before or Chain::link_after.

The data is initialized with the passed-in value.

Trait Implementations

impl<P: Key> AfterMiddleware for Write<P>

where P::Value: Send,

fn after(&self, _: &mut Request<'_, '_>, res: Response) -> IronResult<Response>

Do whatever post-processing this middleware should do.

fn catch( &self, _: &mut Request<'_, '_>, err: IronError, ) -> Result<Response, IronError>

Respond to an error thrown by previous AfterMiddleware, the Handler, or a BeforeMiddleware.

impl<P: Key> BeforeMiddleware for Write<P>

where P::Value: Send,

fn before(&self, req: &mut Request<'_, '_>) -> IronResult<()>

Do whatever work this middleware should do with a Request object.

fn catch( &self, _: &mut Request<'_, '_>, err: IronError, ) -> Result<(), IronError>

Respond to an error thrown by a previous BeforeMiddleware.

impl<P: Key> Clone for Write<P>

where P::Value: Send,

fn clone(&self) -> Write<P>

Returns a copy of the value.

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

Performs copy-assignment from source.

impl<P: Key> Key for Write<P>

where P::Value: 'static,

type Value = Arc<Mutex<<P as Key>::Value>>

The value type associated with this key type.

impl<'a, 'b, P: Key> Plugin<Request<'a, 'b>> for Write<P>

where P::Value: Send,

type Error = PersistentError

The error type associated with this plugin.

fn eval( req: &mut Request<'a, 'b>, ) -> Result<Arc<Mutex<P::Value>>, PersistentError>

Create the plugin from an instance of the extended type.