Module connect

Connectors used by the Client.

This module contains:

• A default HttpConnector that does DNS resolution and establishes connections over TCP.
• Types to build custom connectors.

Connectors

A “connector” is a Service that takes a Uri destination, and its Response is some type implementing Read, Write, and Connection.

Custom Connectors

A simple connector that ignores the Uri destination and always returns a TCP connection to the same address could be written like this:

let connector = tower::service_fn(|_dst| async {
    tokio::net::TcpStream::connect("127.0.0.1:1337")
})

Or, fully written out:

use std::{future::Future, net::SocketAddr, pin::Pin, task::{self, Poll}};
use http::Uri;
use tokio::net::TcpStream;
use tower_service::Service;

#[derive(Clone)]
struct LocalConnector;

impl Service<Uri> for LocalConnector {
    type Response = TcpStream;
    type Error = std::io::Error;
    // We can't "name" an `async` generated future.
    type Future = Pin<Box<
        dyn Future<Output = Result<Self::Response, Self::Error>> + Send
    >>;

    fn poll_ready(&mut self, _: &mut task::Context<'_>) -> Poll<Result<(), Self::Error>> {
        // This connector is always ready, but others might not be.
        Poll::Ready(Ok(()))
    }

    fn call(&mut self, _: Uri) -> Self::Future {
        Box::pin(TcpStream::connect(SocketAddr::from(([127, 0, 0, 1], 1337))))
    }
}

It’s worth noting that for TcpStreams, the HttpConnector is a better starting place to extend from.

Modules

dns

DNS Resolution used by the HttpConnector.

Structs

CaptureConnection

CaptureConnection allows callers to capture Connected information

Connected

Extra information about the connected transport.

HttpConnector

A connector for the http scheme.

HttpInfo

Extra information about the transport when an HttpConnector is used.

Traits

Connect

Connect to a destination, returning an IO transport.

Connection

Describes a type returned by a connector.

Functions

capture_connection

Capture the connection for a given request