//! HTTP Upgrades
//!
//! This module deals with managing [HTTP Upgrades][mdn] in hyper. Since
//! several concepts in HTTP allow for first talking HTTP, and then converting
//! to a different protocol, this module conflates them into a single API.
//! Those include:
//!
//! - HTTP/1.1 Upgrades
//! - HTTP `CONNECT`
//!
//! You are responsible for any other pre-requisites to establish an upgrade,
//! such as sending the appropriate headers, methods, and status codes. You can
//! then use [`on`][] to grab a `Future` which will resolve to the upgraded
//! connection object, or an error if the upgrade fails.
//!
//! [mdn]:
https://developer.mozilla.org/en-US/docs/Web/HTTP/Protocol_upgrade_mechanism
//!
//! # Client
//!
//! Sending an HTTP upgrade from the [`client`](super::client) involves setting
//! either the appropriate method, if wanting to `CONNECT`, or headers such as
//! `Upgrade` and `Connection`, on the `http::Request`. Once receiving the
//! `http::Response` back, you must check for the specific information that the
//! upgrade is agreed upon by the server (such as a `101` status code), and then
//! get the `Future` from the `Response`.
//!
//! # Server
//!
//! Receiving upgrade requests in a server requires you to check the relevant
//! headers in a `Request`, and if an upgrade should be done, you then send the
//! corresponding headers in a response. To then wait for hyper to finish the
//! upgrade, you call `on()` with the `Request`, and then can spawn a task
//! awaiting it.
//!
//! # Example
//!
//! See [this example][example] showing how upgrades work with both
//! Clients and Servers.
//!
//! [example]:
https://github.com/hyperium/hyper/blob/master/examples/upgrades.rs
use std::any::TypeId;
use std::error::Error as StdError;
use std::fmt;
use std::io;
use std::marker::Unpin;
use bytes::Bytes;
use tokio::io::{AsyncRead, AsyncWrite, ReadBuf};
use tokio::sync::oneshot;
#[cfg(any(feature = "http1", feature = "http2"))]
use tracing::trace;
use crate::common::io::Rewind;
use crate::common::{task, Future, Pin, Poll};
/// An upgraded HTTP connection.
///
/// This type holds a trait object internally of the original IO that
/// was used to speak HTTP before the upgrade. It can be used directly
/// as a `Read` or `Write` for convenience.
///
/// Alternatively, if the exact type is known, this can be deconstructed
/// into its parts.
pub struct Upgraded {
io: Rewind<Box<dyn Io + Send>>,
}
/// A future for a possible HTTP upgrade.
///
/// If no upgrade was available, or it doesn't succeed, yields an `Error`.
pub struct OnUpgrade {
rx: Option<oneshot::Receiver<crate::Result<Upgraded>>>,
}
/// The deconstructed parts of an [`Upgraded`](Upgraded) type.
///
/// Includes the original IO type, and a read buffer of bytes that the
/// HTTP state machine may have already read before completing an upgrade.
#[derive(Debug)]
pub struct Parts<T> {
/// The original IO object used before the upgrade.
pub io: T,
/// A buffer of bytes that have been read but not processed as HTTP.
///
/// For instance, if the `Connection` is used for an HTTP upgrade request,
/// it is possible the server sent back the first bytes of the new protocol
/// along with the response upgrade.
///
/// You will want to check for any existing bytes if you plan to continue
/// communicating on the IO object.
pub read_buf: Bytes,
_inner: (),
}
/// Gets a pending HTTP upgrade from this message.
///
/// This can be called on the following types:
///
/// - `http::Request<B>`
/// - `http::Response<B>`
/// - `&mut http::Request<B>`
/// - `&mut http::Response<B>`
pub fn on<T: sealed::CanUpgrade>(msg: T) -> OnUpgrade {
msg.on_upgrade()
}
#[cfg(any(feature = "http1", feature = "http2"))]
pub(super) struct Pending {
tx: oneshot::Sender<crate::Result<Upgraded>>,
}
#[cfg(any(feature = "http1", feature = "http2"))]
pub(super) fn pending() -> (Pending, OnUpgrade) {
let (tx, rx) = oneshot::channel();
(Pending { tx }, OnUpgrade { rx: Some(rx) })
}
// ===== impl Upgraded =====
impl Upgraded {
#[cfg(any(feature = "http1", feature = "http2", test))]
pub(super) fn new<T>(io: T, read_buf: Bytes) -> Self
where
T: AsyncRead + AsyncWrite + Unpin + Send + 'static,
{
Upgraded {
io: Rewind::new_buffered(Box::new(io), read_buf),
}
}
/// Tries to downcast the internal trait object to the type passed.
///
/// On success, returns the downcasted parts. On error, returns the
/// `Upgraded` back.
pub fn downcast<T: AsyncRead + AsyncWrite + Unpin + 'static>(self) -> Result<Parts<T>, Self> {
let (io, buf) = self.io.into_inner();
match io.__hyper_downcast() {
Ok(t) => Ok(Parts {
io: *t,
read_buf: buf,
_inner: (),
}),
Err(io) => Err(Upgraded {
io: Rewind::new_buffered(io, buf),
}),
}
}
}
impl AsyncRead for Upgraded {
fn poll_read(
mut self: Pin<&mut Self>,
cx: &mut task::Context<'_>,
buf: &mut ReadBuf<'_>,
) -> Poll<io::Result<()>> {
Pin::new(&mut self.io).poll_read(cx, buf)
}
}
impl AsyncWrite for Upgraded {
fn poll_write(
mut self: Pin<&mut Self>,
cx: &mut task::Context<'_>,
buf: &[u8],
) -> Poll<io::Result<usize>> {
Pin::new(&mut self.io).poll_write(cx, buf)
}
fn poll_write_vectored(
mut self: Pin<&mut Self>,
cx: &mut task::Context<'_>,
bufs: &[io::IoSlice<'_>],
) -> Poll<io::Result<usize>> {
Pin::new(&mut self.io).poll_write_vectored(cx, bufs)
}
fn poll_flush(mut self: Pin<&mut Self>, cx: &mut task::Context<'_>) -> Poll<io::Result<()>> {
Pin::new(&mut self.io).poll_flush(cx)
}
fn poll_shutdown(mut self: Pin<&mut Self>, cx: &mut task::Context<'_>) -> Poll<io::Result<()>> {
Pin::new(&mut self.io).poll_shutdown(cx)
}
fn is_write_vectored(&self) -> bool {
self.io.is_write_vectored()
}
}
impl fmt::Debug for Upgraded {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
f.debug_struct("Upgraded").finish()
}
}
// ===== impl OnUpgrade =====
impl OnUpgrade {
pub(super) fn none() -> Self {
OnUpgrade { rx: None }
}
#[cfg(feature = "http1")]
pub(super) fn is_none(&self) -> bool {
self.rx.is_none()
}
}
impl Future for OnUpgrade {
type Output = Result<Upgraded, crate::Error>;
fn poll(mut self: Pin<&mut Self>, cx: &mut task::Context<'_>) -> Poll<Self::Output> {
match self.rx {
Some(ref mut rx) => Pin::new(rx).poll(cx).map(|res| match res {
Ok(Ok(upgraded)) => Ok(upgraded),
Ok(Err(err)) => Err(err),
Err(_oneshot_canceled) => Err(crate::Error::new_canceled().with(UpgradeExpected)),
}),
None => Poll::Ready(Err(crate::Error::new_user_no_upgrade())),
}
}
}
impl fmt::Debug for OnUpgrade {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
f.debug_struct("OnUpgrade").finish()
}
}
// ===== impl Pending =====
#[cfg(any(feature = "http1", feature = "http2"))]
impl Pending {
pub(super) fn fulfill(self, upgraded: Upgraded) {
trace!("pending upgrade fulfill");
let _ = self.tx.send(Ok(upgraded));
}
#[cfg(feature = "http1")]
/// Don't fulfill the pending Upgrade, but instead signal that
/// upgrades are handled manually.
pub(super) fn manual(self) {
trace!("pending upgrade handled manually");
let _ = self.tx.send(Err(crate::Error::new_user_manual_upgrade()));
}
}
// ===== impl UpgradeExpected =====
/// Error cause returned when an upgrade was expected but canceled
/// for whatever reason.
///
/// This likely means the actual `Conn` future wasn't polled and upgraded.
#[derive(Debug)]
struct UpgradeExpected;
impl fmt::Display for UpgradeExpected {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
f.write_str("upgrade expected but not completed")
}
}
impl StdError for UpgradeExpected {}
// ===== impl Io =====
pub(super) trait Io: AsyncRead + AsyncWrite + Unpin + 'static {
fn __hyper_type_id(&self) -> TypeId {
TypeId::of::<Self>()
}
}
impl<T: AsyncRead + AsyncWrite + Unpin + 'static> Io for T {}
impl dyn Io + Send {
fn __hyper_is<T: Io>(&self) -> bool {
let t = TypeId::of::<T>();
self.__hyper_type_id() == t
}
fn __hyper_downcast<T: Io>(self: Box<Self>) -> Result<Box<T>, Box<Self>> {
if self.__hyper_is::<T>() {
// Taken from `std::error::Error::downcast()`.
unsafe {
let raw: *mut dyn Io = Box::into_raw(self);
Ok(Box::from_raw(raw as *mut T))
}
} else {
Err(self)
}
}
}
mod sealed {
use super::OnUpgrade;
pub trait CanUpgrade {
fn on_upgrade(self) -> OnUpgrade;
}
impl<B> CanUpgrade for http::Request<B> {
fn on_upgrade(mut self) -> OnUpgrade {
self.extensions_mut()
.remove::<OnUpgrade>()
.unwrap_or_else(OnUpgrade::none)
}
}
impl<B> CanUpgrade for &'_ mut http::Request<B> {
fn on_upgrade(self) -> OnUpgrade {
self.extensions_mut()
.remove::<OnUpgrade>()
.unwrap_or_else(OnUpgrade::none)
}
}
impl<B> CanUpgrade for http::Response<B> {
fn on_upgrade(mut self) -> OnUpgrade {
self.extensions_mut()
.remove::<OnUpgrade>()
.unwrap_or_else(OnUpgrade::none)
}
}
impl<B> CanUpgrade for &'_ mut http::Response<B> {
fn on_upgrade(self) -> OnUpgrade {
self.extensions_mut()
.remove::<OnUpgrade>()
.unwrap_or_else(OnUpgrade::none)
}
}
}
#[cfg(test)]
mod tests {
use super::*;
#[test]
fn upgraded_downcast() {
let upgraded = Upgraded::new(Mock, Bytes::new());
let upgraded = upgraded.downcast::<std::io::Cursor<Vec<u8>>>().unwrap_err();
upgraded.downcast::<Mock>().unwrap();
}
// TODO: replace with tokio_test::io when it can test write_buf
struct Mock;
impl AsyncRead for Mock {
fn poll_read(
self: Pin<&mut Self>,
_cx: &mut task::Context<'_>,
_buf: &mut ReadBuf<'_>,
) -> Poll<io::Result<()>> {
unreachable!("Mock::poll_read")
}
}
impl AsyncWrite for Mock {
fn poll_write(
self: Pin<&mut Self>,
_: &mut task::Context<'_>,
buf: &[u8],
) -> Poll<io::Result<usize>> {
// panic!("poll_write shouldn't be called");
Poll::Ready(Ok(buf.len()))
}
fn poll_flush(self: Pin<&mut Self>, _cx: &mut task::Context<'_>) -> Poll<io::Result<()>> {
unreachable!("Mock::poll_flush")
}
fn poll_shutdown(
self: Pin<&mut Self>,
_cx: &mut task::Context<'_>,
) -> Poll<io::Result<()>> {
unreachable!("Mock::poll_shutdown")
}
}
}
