Trait Service

trait Service<Request>

An asynchronous function from a Request to a Response.

The Service trait is a simplified interface making it easy to write network applications in a modular and reusable way, decoupled from the underlying protocol.

Functional

A Service is a function of a Request. It immediately returns a Future representing the eventual completion of processing the request. The actual request processing may happen at any time in the future, on any thread or executor. The processing may depend on calling other services. At some point in the future, the processing will complete, and the Future will resolve to a response or error.

At a high level, the Service::call function represents an RPC request. The Service value can be a server or a client.

Associated Types

type Response

Responses given by the service.

type Error

Errors produced by the service.

Note: Returning an Error to a hyper server, the behavior depends on the protocol. In most cases, hyper will cause the connection to be abruptly aborted. It will abort the request however the protocol allows, either with some sort of RST_STREAM, or killing the connection if that doesn't exist.

type Future: TraitBound { trait_: Path { path: "Future", id: Id(268), args: Some(AngleBracketed { args: [], constraints: [AssocItemConstraint { name: "Output", args: None, binding: Equality(Type(ResolvedPath(Path { path: "Result", id: Id(34), args: Some(AngleBracketed { args: [Type(QualifiedPath { name: "Response", args: None, self_type: Generic("Self"), trait_: Some(Path { path: "", id: Id(402), args: None }) }), Type(QualifiedPath { name: "Error", args: None, self_type: Generic("Self"), trait_: Some(Path { path: "", id: Id(402), args: None }) })], constraints: [] }) }))) }] }) }, generic_params: [], modifier: None }

The future response value.

Required Methods

fn call(self: &Self, req: Request) -> <Self as >::Future

Process the request and return the response asynchronously. call takes &self instead of mut &self because:

  • It prepares the way for async fn, since then the future only borrows &self, and thus a Service can concurrently handle multiple outstanding requests at once.
  • It's clearer that Services can likely be cloned
  • To share state across clones, you generally need Arc<Mutex<_>> That means you're not really using the &mut self and could do with a &self. The discussion on this is here: https://github.com/hyperium/hyper/issues/3040

Implementors