Trait actix_web::dev::Service [−][src]
An asynchronous operation from Request
to a Response
.
The Service
trait models a request/response interaction, receiving requests and returning
replies. You can think about a service as a function with one argument that returns some result
asynchronously. Conceptually, the operation looks like this:
async fn(Request) -> Result<Response, Err>
The Service
trait just generalizes this form where each parameter is described as an
associated type on the trait. Services can also have mutable state that influence computation.
Service
provides a symmetric and uniform API; the same abstractions can be used to represent
both clients and servers. Services describe only transformation operations which encourage
simple API surfaces. This leads to simpler design of each service, improves test-ability and
makes composition easier.
struct MyService; impl Service for MyService { type Request = u8; type Response = u64; type Error = MyError; type Future = Pin<Box<Future<Output=Result<Self::Response, Self::Error>>>>; fn poll_ready(&self, cx: &mut Context<'_>) -> Poll<Result<(), Self::Error>> { ... } fn call(&self, req: Self::Request) -> Self::Future { ... } }
Sometimes it is not necessary to implement the Service trait. For example, the above service could be rewritten as a simple function and passed to fn_service.
async fn my_service(req: u8) -> Result<u64, MyError>;
Associated Types
type Response
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Responses given by the service.
type Error
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Errors produced by the service when polling readiness or executing call.
type Future: Future
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The future response value.
Required methods
pub fn poll_ready(&self, ctx: &mut Context<'_>) -> Poll<Result<(), Self::Error>>
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Returns Ready
when the service is able to process requests.
If the service is at capacity, then Pending
is returned and the task
is notified when the service becomes ready again. This function is
expected to be called while on a task.
This is a best effort implementation. False positives are permitted.
It is permitted for the service to return Ready
from a poll_ready
call and the next invocation of call
results in an error.
Notes
poll_ready
might be called on a different task tocall
.- In cases of chained services,
.poll_ready()
is called for all services at once.
pub fn call(&self, req: Req) -> Self::Future
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Process the request and return the response asynchronously.
This function is expected to be callable off task. As such,
implementations should take care to not call poll_ready
. If the
service is at capacity and the request is unable to be handled, the
returned Future
should resolve to an error.
Calling call
without calling poll_ready
is permitted. The
implementation must be resilient to this fact.
Implementations on Foreign Types
impl<T> Service<(Request<Pin<Box<dyn Stream<Item = Result<Bytes, PayloadError>> + 'static, Global>>>, Framed<T, Codec>)> for UpgradeHandler
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type Response = ()
type Error = Error
type Future = Pin<Box<dyn Future<Output = Result<<UpgradeHandler as Service<(Request<Pin<Box<dyn Stream<Item = Result<Bytes, PayloadError>> + 'static, Global>>>, Framed<T, Codec>)>>::Response, <UpgradeHandler as Service<(Request<Pin<Box<dyn Stream<Item = Result<Bytes, PayloadError>> + 'static, Global>>>, Framed<T, Codec>)>>::Error>> + 'static, Global>>
pub fn poll_ready(
&self,
&mut Context<'_>
) -> Poll<Result<(), <UpgradeHandler as Service<(Request<Pin<Box<dyn Stream<Item = Result<Bytes, PayloadError>> + 'static, Global>>>, Framed<T, Codec>)>>::Error>>
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&self,
&mut Context<'_>
) -> Poll<Result<(), <UpgradeHandler as Service<(Request<Pin<Box<dyn Stream<Item = Result<Bytes, PayloadError>> + 'static, Global>>>, Framed<T, Codec>)>>::Error>>
pub fn call(
&self,
(Request<Pin<Box<dyn Stream<Item = Result<Bytes, PayloadError>> + 'static, Global>>>, Framed<T, Codec>)
) -> <UpgradeHandler as Service<(Request<Pin<Box<dyn Stream<Item = Result<Bytes, PayloadError>> + 'static, Global>>>, Framed<T, Codec>)>>::Future
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&self,
(Request<Pin<Box<dyn Stream<Item = Result<Bytes, PayloadError>> + 'static, Global>>>, Framed<T, Codec>)
) -> <UpgradeHandler as Service<(Request<Pin<Box<dyn Stream<Item = Result<Bytes, PayloadError>> + 'static, Global>>>, Framed<T, Codec>)>>::Future
impl Service<Request<Pin<Box<dyn Stream<Item = Result<Bytes, PayloadError>> + 'static, Global>>>> for ExpectHandler
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type Response = Request<Pin<Box<dyn Stream<Item = Result<Bytes, PayloadError>> + 'static, Global>>>
type Error = Error
type Future = Ready<Result<<ExpectHandler as Service<Request<Pin<Box<dyn Stream<Item = Result<Bytes, PayloadError>> + 'static, Global>>>>>::Response, <ExpectHandler as Service<Request<Pin<Box<dyn Stream<Item = Result<Bytes, PayloadError>> + 'static, Global>>>>>::Error>>
pub fn poll_ready(
&self,
&mut Context<'_>
) -> Poll<Result<(), <ExpectHandler as Service<Request<Pin<Box<dyn Stream<Item = Result<Bytes, PayloadError>> + 'static, Global>>>>>::Error>>
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&self,
&mut Context<'_>
) -> Poll<Result<(), <ExpectHandler as Service<Request<Pin<Box<dyn Stream<Item = Result<Bytes, PayloadError>> + 'static, Global>>>>>::Error>>
pub fn call(
&self,
req: Request<Pin<Box<dyn Stream<Item = Result<Bytes, PayloadError>> + 'static, Global>>>
) -> <ExpectHandler as Service<Request<Pin<Box<dyn Stream<Item = Result<Bytes, PayloadError>> + 'static, Global>>>>>::Future
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&self,
req: Request<Pin<Box<dyn Stream<Item = Result<Bytes, PayloadError>> + 'static, Global>>>
) -> <ExpectHandler as Service<Request<Pin<Box<dyn Stream<Item = Result<Bytes, PayloadError>> + 'static, Global>>>>>::Future
impl<S, Req> Service<Req> for Rc<S> where
S: Service<Req> + ?Sized,
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S: Service<Req> + ?Sized,
type Response = <S as Service<Req>>::Response
type Error = <S as Service<Req>>::Error
type Future = <S as Service<Req>>::Future
pub fn poll_ready(
&self,
ctx: &mut Context<'_>
) -> Poll<Result<(), <Rc<S> as Service<Req>>::Error>>
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&self,
ctx: &mut Context<'_>
) -> Poll<Result<(), <Rc<S> as Service<Req>>::Error>>
pub fn call(&self, request: Req) -> <S as Service<Req>>::Future
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impl<S, Req> Service<Req> for RefCell<S> where
S: Service<Req>,
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S: Service<Req>,
This impl is deprecated since v2 because the Service
trait now receives shared reference.
type Response = <S as Service<Req>>::Response
type Error = <S as Service<Req>>::Error
type Future = <S as Service<Req>>::Future
pub fn poll_ready(
&self,
ctx: &mut Context<'_>
) -> Poll<Result<(), <RefCell<S> as Service<Req>>::Error>>
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&self,
ctx: &mut Context<'_>
) -> Poll<Result<(), <RefCell<S> as Service<Req>>::Error>>
pub fn call(&self, request: Req) -> <S as Service<Req>>::Future
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impl<'a, S, Req> Service<Req> for &'a mut S where
S: Service<Req> + 'a,
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S: Service<Req> + 'a,
type Response = <S as Service<Req>>::Response
type Error = <S as Service<Req>>::Error
type Future = <S as Service<Req>>::Future
pub fn poll_ready(
&self,
ctx: &mut Context<'_>
) -> Poll<Result<(), <&'a mut S as Service<Req>>::Error>>
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&self,
ctx: &mut Context<'_>
) -> Poll<Result<(), <&'a mut S as Service<Req>>::Error>>
pub fn call(&self, request: Req) -> <S as Service<Req>>::Future
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impl<S, Req> Service<Req> for Box<S, Global> where
S: Service<Req> + ?Sized,
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S: Service<Req> + ?Sized,
type Response = <S as Service<Req>>::Response
type Error = <S as Service<Req>>::Error
type Future = <S as Service<Req>>::Future
pub fn poll_ready(
&self,
ctx: &mut Context<'_>
) -> Poll<Result<(), <S as Service<Req>>::Error>>
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&self,
ctx: &mut Context<'_>
) -> Poll<Result<(), <S as Service<Req>>::Error>>
pub fn call(&self, request: Req) -> <S as Service<Req>>::Future
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impl<'a, S, Req> Service<Req> for &'a S where
S: Service<Req> + 'a,
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S: Service<Req> + 'a,
type Response = <S as Service<Req>>::Response
type Error = <S as Service<Req>>::Error
type Future = <S as Service<Req>>::Future
pub fn poll_ready(
&self,
ctx: &mut Context<'_>
) -> Poll<Result<(), <&'a S as Service<Req>>::Error>>
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&self,
ctx: &mut Context<'_>
) -> Poll<Result<(), <&'a S as Service<Req>>::Error>>
pub fn call(&self, request: Req) -> <S as Service<Req>>::Future
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impl<S, Req> Service<Req> for Pipeline<S, Req> where
S: Service<Req>,
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S: Service<Req>,
type Response = <S as Service<Req>>::Response
type Error = <S as Service<Req>>::Error
type Future = <S as Service<Req>>::Future
pub fn poll_ready(
&self,
ctx: &mut Context<'_>
) -> Poll<Result<(), <S as Service<Req>>::Error>>
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&self,
ctx: &mut Context<'_>
) -> Poll<Result<(), <S as Service<Req>>::Error>>
pub fn call(&self, req: Req) -> <Pipeline<S, Req> as Service<Req>>::Future
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impl<T> Service<Connect<T>> for TcpConnector where
T: Address,
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T: Address,
type Response = Connection<T, TcpStream>
type Error = ConnectError
type Future = TcpConnectorResponse<T>
pub fn poll_ready(
&self,
&mut Context<'_>
) -> Poll<Result<(), <TcpConnector as Service<Connect<T>>>::Error>>
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&self,
&mut Context<'_>
) -> Poll<Result<(), <TcpConnector as Service<Connect<T>>>::Error>>
pub fn call(
&self,
req: Connect<T>
) -> <TcpConnector as Service<Connect<T>>>::Future
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&self,
req: Connect<T>
) -> <TcpConnector as Service<Connect<T>>>::Future
impl<T, U> Service<Connection<T, U>> for OpensslConnectorService where
T: Address,
U: ActixStream,
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T: Address,
U: ActixStream,
type Response = Connection<T, SslStream<U>>
type Error = Error
type Future = ConnectAsyncExt<T, U>
pub fn poll_ready(
&self,
&mut Context<'_>
) -> Poll<Result<(), <OpensslConnectorService as Service<Connection<T, U>>>::Error>>
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&self,
&mut Context<'_>
) -> Poll<Result<(), <OpensslConnectorService as Service<Connection<T, U>>>::Error>>
pub fn call(
&self,
stream: Connection<T, U>
) -> <OpensslConnectorService as Service<Connection<T, U>>>::Future
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&self,
stream: Connection<T, U>
) -> <OpensslConnectorService as Service<Connection<T, U>>>::Future
impl<T> Service<Connect<T>> for ConnectService where
T: Address,
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T: Address,
type Response = Connection<T, TcpStream>
type Error = ConnectError
type Future = ConnectServiceResponse<T>
pub fn poll_ready(
&self,
&mut Context<'_>
) -> Poll<Result<(), <ConnectService as Service<Connect<T>>>::Error>>
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&self,
&mut Context<'_>
) -> Poll<Result<(), <ConnectService as Service<Connect<T>>>::Error>>
pub fn call(
&self,
req: Connect<T>
) -> <ConnectService as Service<Connect<T>>>::Future
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&self,
req: Connect<T>
) -> <ConnectService as Service<Connect<T>>>::Future
impl<T> Service<Connect<T>> for Resolver where
T: Address,
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T: Address,
type Response = Connect<T>
type Error = ConnectError
type Future = ResolverFuture<T>
pub fn poll_ready(
&self,
&mut Context<'_>
) -> Poll<Result<(), <Resolver as Service<Connect<T>>>::Error>>
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&self,
&mut Context<'_>
) -> Poll<Result<(), <Resolver as Service<Connect<T>>>::Error>>
pub fn call(&self, req: Connect<T>) -> <Resolver as Service<Connect<T>>>::Future
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impl<T> Service<T> for AcceptorService where
T: ActixStream,
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T: ActixStream,
type Response = TlsStream<T>
type Error = Error
type Future = AcceptorServiceFut<T>
pub fn poll_ready(
&self,
cx: &mut Context<'_>
) -> Poll<Result<(), <AcceptorService as Service<T>>::Error>>
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&self,
cx: &mut Context<'_>
) -> Poll<Result<(), <AcceptorService as Service<T>>::Error>>
pub fn call(&self, req: T) -> <AcceptorService as Service<T>>::Future
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impl<T, U> Service<Connection<T, U>> for RustlsConnectorService where
T: Address,
U: ActixStream,
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T: Address,
U: ActixStream,
type Response = Connection<T, TlsStream<U>>
type Error = Error
type Future = RustlsConnectorServiceFuture<T, U>
pub fn poll_ready(
&self,
&mut Context<'_>
) -> Poll<Result<(), <RustlsConnectorService as Service<Connection<T, U>>>::Error>>
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&self,
&mut Context<'_>
) -> Poll<Result<(), <RustlsConnectorService as Service<Connection<T, U>>>::Error>>
pub fn call(
&self,
connection: Connection<T, U>
) -> <RustlsConnectorService as Service<Connection<T, U>>>::Future
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&self,
connection: Connection<T, U>
) -> <RustlsConnectorService as Service<Connection<T, U>>>::Future
impl<T> Service<T> for AcceptorService where
T: ActixStream,
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T: ActixStream,
type Response = TlsStream<T>
type Error = Error
type Future = AcceptorServiceResponse<T>
pub fn poll_ready(
&self,
ctx: &mut Context<'_>
) -> Poll<Result<(), <AcceptorService as Service<T>>::Error>>
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&self,
ctx: &mut Context<'_>
) -> Poll<Result<(), <AcceptorService as Service<T>>::Error>>