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//! 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 [`AsyncRead`][], [`AsyncWrite`][],
//! 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:
//!
//! ```rust,ignore
//! let connector = tower::service_fn(|_dst| async {
//! tokio::net::TcpStream::connect("127.0.0.1:1337")
//! })
//! ```
//!
//! Or, fully written out:
//!
//! ```
//! # #[cfg(feature = "runtime")]
//! # mod rt {
//! use std::{future::Future, net::SocketAddr, pin::Pin, task::{self, Poll}};
//! use hyper::{service::Service, Uri};
//! use tokio::net::TcpStream;
//!
//! #[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 `TcpStream`s, the [`HttpConnector`][] is a
//! better starting place to extend from.
//!
//! Using either of the above connector examples, it can be used with the
//! `Client` like this:
//!
//! ```
//! # #[cfg(feature = "runtime")]
//! # fn rt () {
//! # let connector = hyper::client::HttpConnector::new();
//! // let connector = ...
//!
//! let client = hyper::Client::builder()
//! .build::<_, hyper::Body>(connector);
//! # }
//! ```
//!
//!
//! [`HttpConnector`]: HttpConnector
//! [`Service`]: crate::service::Service
//! [`Uri`]: ::http::Uri
//! [`AsyncRead`]: tokio::io::AsyncRead
//! [`AsyncWrite`]: tokio::io::AsyncWrite
//! [`Connection`]: Connection
use std::fmt;
use ::http::Extensions;
cfg_feature! {
#![feature = "tcp"]
pub use self::http::{HttpConnector, HttpInfo};
pub mod dns;
mod http;
}
cfg_feature! {
#![any(feature = "http1", feature = "http2")]
pub use self::sealed::Connect;
}
/// Describes a type returned by a connector.
pub trait Connection {
/// Return metadata describing the connection.
fn connected(&self) -> Connected;
}
/// Extra information about the connected transport.
///
/// This can be used to inform recipients about things like if ALPN
/// was used, or if connected to an HTTP proxy.
#[derive(Debug)]
pub struct Connected {
pub(super) alpn: Alpn,
pub(super) is_proxied: bool,
pub(super) extra: Option<Extra>,
}
pub(super) struct Extra(Box<dyn ExtraInner>);
#[derive(Clone, Copy, Debug, PartialEq)]
pub(super) enum Alpn {
H2,
None,
}
impl Connected {
/// Create new `Connected` type with empty metadata.
pub fn new() -> Connected {
Connected {
alpn: Alpn::None,
is_proxied: false,
extra: None,
}
}
/// Set whether the connected transport is to an HTTP proxy.
///
/// This setting will affect if HTTP/1 requests written on the transport
/// will have the request-target in absolute-form or origin-form:
///
/// - When `proxy(false)`:
///
/// ```http
/// GET /guide HTTP/1.1
/// ```
///
/// - When `proxy(true)`:
///
/// ```http
/// ```
///
/// Default is `false`.
pub fn proxy(mut self, is_proxied: bool) -> Connected {
self.is_proxied = is_proxied;
self
}
/// Determines if the connected transport is to an HTTP proxy.
pub fn is_proxied(&self) -> bool {
self.is_proxied
}
/// Set extra connection information to be set in the extensions of every `Response`.
pub fn extra<T: Clone + Send + Sync + 'static>(mut self, extra: T) -> Connected {
if let Some(prev) = self.extra {
self.extra = Some(Extra(Box::new(ExtraChain(prev.0, extra))));
} else {
self.extra = Some(Extra(Box::new(ExtraEnvelope(extra))));
}
self
}
/// Copies the extra connection information into an `Extensions` map.
pub fn get_extras(&self, extensions: &mut Extensions) {
if let Some(extra) = &self.extra {
extra.set(extensions);
}
}
/// Set that the connected transport negotiated HTTP/2 as its next protocol.
pub fn negotiated_h2(mut self) -> Connected {
self.alpn = Alpn::H2;
self
}
/// Determines if the connected transport negotiated HTTP/2 as its next protocol.
pub fn is_negotiated_h2(&self) -> bool {
self.alpn == Alpn::H2
}
// Don't public expose that `Connected` is `Clone`, unsure if we want to
// keep that contract...
#[cfg(feature = "http2")]
pub(super) fn clone(&self) -> Connected {
Connected {
alpn: self.alpn.clone(),
is_proxied: self.is_proxied,
extra: self.extra.clone(),
}
}
}
// ===== impl Extra =====
impl Extra {
pub(super) fn set(&self, res: &mut Extensions) {
self.0.set(res);
}
}
impl Clone for Extra {
fn clone(&self) -> Extra {
Extra(self.0.clone_box())
}
}
impl fmt::Debug for Extra {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
f.debug_struct("Extra").finish()
}
}
trait ExtraInner: Send + Sync {
fn clone_box(&self) -> Box<dyn ExtraInner>;
fn set(&self, res: &mut Extensions);
}
// This indirection allows the `Connected` to have a type-erased "extra" value,
// while that type still knows its inner extra type. This allows the correct
// TypeId to be used when inserting into `res.extensions_mut()`.
#[derive(Clone)]
struct ExtraEnvelope<T>(T);
impl<T> ExtraInner for ExtraEnvelope<T>
where
T: Clone + Send + Sync + 'static,
{
fn clone_box(&self) -> Box<dyn ExtraInner> {
Box::new(self.clone())
}
fn set(&self, res: &mut Extensions) {
res.insert(self.0.clone());
}
}
struct ExtraChain<T>(Box<dyn ExtraInner>, T);
impl<T: Clone> Clone for ExtraChain<T> {
fn clone(&self) -> Self {
ExtraChain(self.0.clone_box(), self.1.clone())
}
}
impl<T> ExtraInner for ExtraChain<T>
where
T: Clone + Send + Sync + 'static,
{
fn clone_box(&self) -> Box<dyn ExtraInner> {
Box::new(self.clone())
}
fn set(&self, res: &mut Extensions) {
self.0.set(res);
res.insert(self.1.clone());
}
}
#[cfg(any(feature = "http1", feature = "http2"))]
pub(super) mod sealed {
use std::error::Error as StdError;
use ::http::Uri;
use tokio::io::{AsyncRead, AsyncWrite};
use super::Connection;
use crate::common::{Future, Unpin};
/// Connect to a destination, returning an IO transport.
///
/// A connector receives a [`Uri`](::http::Uri) and returns a `Future` of the
/// ready connection.
///
/// # Trait Alias
///
/// This is really just an *alias* for the `tower::Service` trait, with
/// additional bounds set for convenience *inside* hyper. You don't actually
/// implement this trait, but `tower::Service<Uri>` instead.
// The `Sized` bound is to prevent creating `dyn Connect`, since they cannot
// fit the `Connect` bounds because of the blanket impl for `Service`.
pub trait Connect: Sealed + Sized {
#[doc(hidden)]
type _Svc: ConnectSvc;
#[doc(hidden)]
fn connect(self, internal_only: Internal, dst: Uri) -> <Self::_Svc as ConnectSvc>::Future;
}
pub trait ConnectSvc {
type Connection: AsyncRead + AsyncWrite + Connection + Unpin + Send + 'static;
type Error: Into<Box<dyn StdError + Send + Sync>>;
type Future: Future<Output = Result<Self::Connection, Self::Error>> + Unpin + Send + 'static;
fn connect(self, internal_only: Internal, dst: Uri) -> Self::Future;
}
impl<S, T> Connect for S
where
S: tower_service::Service<Uri, Response = T> + Send + 'static,
S::Error: Into<Box<dyn StdError + Send + Sync>>,
S::Future: Unpin + Send,
T: AsyncRead + AsyncWrite + Connection + Unpin + Send + 'static,
{
type _Svc = S;
fn connect(self, _: Internal, dst: Uri) -> crate::service::Oneshot<S, Uri> {
crate::service::oneshot(self, dst)
}
}
impl<S, T> ConnectSvc for S
where
S: tower_service::Service<Uri, Response = T> + Send + 'static,
S::Error: Into<Box<dyn StdError + Send + Sync>>,
S::Future: Unpin + Send,
T: AsyncRead + AsyncWrite + Connection + Unpin + Send + 'static,
{
type Connection = T;
type Error = S::Error;
type Future = crate::service::Oneshot<S, Uri>;
fn connect(self, _: Internal, dst: Uri) -> Self::Future {
crate::service::oneshot(self, dst)
}
}
impl<S, T> Sealed for S
where
S: tower_service::Service<Uri, Response = T> + Send,
S::Error: Into<Box<dyn StdError + Send + Sync>>,
S::Future: Unpin + Send,
T: AsyncRead + AsyncWrite + Connection + Unpin + Send + 'static,
{
}
pub trait Sealed {}
#[allow(missing_debug_implementations)]
pub struct Internal;
}
#[cfg(test)]
mod tests {
use super::Connected;
#[derive(Clone, Debug, PartialEq)]
struct Ex1(usize);
#[derive(Clone, Debug, PartialEq)]
struct Ex2(&'static str);
#[derive(Clone, Debug, PartialEq)]
struct Ex3(&'static str);
#[test]
fn test_connected_extra() {
let c1 = Connected::new().extra(Ex1(41));
let mut ex = ::http::Extensions::new();
assert_eq!(ex.get::<Ex1>(), None);
c1.extra.as_ref().expect("c1 extra").set(&mut ex);
assert_eq!(ex.get::<Ex1>(), Some(&Ex1(41)));
}
#[test]
fn test_connected_extra_chain() {
// If a user composes connectors and at each stage, there's "extra"
// info to attach, it shouldn't override the previous extras.
let c1 = Connected::new()
.extra(Ex1(45))
.extra(Ex2("zoom"))
.extra(Ex3("pew pew"));
let mut ex1 = ::http::Extensions::new();
assert_eq!(ex1.get::<Ex1>(), None);
assert_eq!(ex1.get::<Ex2>(), None);
assert_eq!(ex1.get::<Ex3>(), None);
c1.extra.as_ref().expect("c1 extra").set(&mut ex1);
assert_eq!(ex1.get::<Ex1>(), Some(&Ex1(45)));
assert_eq!(ex1.get::<Ex2>(), Some(&Ex2("zoom")));
assert_eq!(ex1.get::<Ex3>(), Some(&Ex3("pew pew")));
// Just like extensions, inserting the same type overrides previous type.
let c2 = Connected::new()
.extra(Ex1(33))
.extra(Ex2("hiccup"))
.extra(Ex1(99));
let mut ex2 = ::http::Extensions::new();
c2.extra.as_ref().expect("c2 extra").set(&mut ex2);
assert_eq!(ex2.get::<Ex1>(), Some(&Ex1(99)));
assert_eq!(ex2.get::<Ex2>(), Some(&Ex2("hiccup")));
}
}