use std::error::Error as StdError;
use bytes::{Buf, Bytes};
use http::Request;
use tokio::io::{AsyncRead, AsyncWrite};
use tracing::{debug, trace};
use super::{Http1Transaction, Wants};
use crate::body::{Body, DecodedLength, HttpBody};
use crate::common::{task, Future, Pin, Poll, Unpin};
use crate::proto::{
BodyLength, Conn, Dispatched, MessageHead, RequestHead,
};
use crate::upgrade::OnUpgrade;
pub(crate) struct Dispatcher<D, Bs: HttpBody, I, T> {
conn: Conn<I, Bs::Data, T>,
dispatch: D,
body_tx: Option<crate::body::Sender>,
body_rx: Pin<Box<Option<Bs>>>,
is_closing: bool,
}
pub(crate) trait Dispatch {
type PollItem;
type PollBody;
type PollError;
type RecvItem;
fn poll_msg(
self: Pin<&mut Self>,
cx: &mut task::Context<'_>,
) -> Poll<Option<Result<(Self::PollItem, Self::PollBody), Self::PollError>>>;
fn recv_msg(&mut self, msg: crate::Result<(Self::RecvItem, Body)>) -> crate::Result<()>;
fn poll_ready(&mut self, cx: &mut task::Context<'_>) -> Poll<Result<(), ()>>;
fn should_poll(&self) -> bool;
}
cfg_server! {
use crate::service::HttpService;
pub(crate) struct Server<S: HttpService<B>, B> {
in_flight: Pin<Box<Option<S::Future>>>,
pub(crate) service: S,
}
}
cfg_client! {
pin_project_lite::pin_project! {
pub(crate) struct Client<B> {
callback: Option<crate::client::dispatch::Callback<Request<B>, http::Response<Body>>>,
#[pin]
rx: ClientRx<B>,
rx_closed: bool,
}
}
type ClientRx<B> = crate::client::dispatch::Receiver<Request<B>, http::Response<Body>>;
}
impl<D, Bs, I, T> Dispatcher<D, Bs, I, T>
where
D: Dispatch<
PollItem = MessageHead<T::Outgoing>,
PollBody = Bs,
RecvItem = MessageHead<T::Incoming>,
> + Unpin,
D::PollError: Into<Box<dyn StdError + Send + Sync>>,
I: AsyncRead + AsyncWrite + Unpin,
T: Http1Transaction + Unpin,
Bs: HttpBody + 'static,
Bs::Error: Into<Box<dyn StdError + Send + Sync>>,
{
pub(crate) fn new(dispatch: D, conn: Conn<I, Bs::Data, T>) -> Self {
Dispatcher {
conn,
dispatch,
body_tx: None,
body_rx: Box::pin(None),
is_closing: false,
}
}
#[cfg(feature = "server")]
pub(crate) fn disable_keep_alive(&mut self) {
self.conn.disable_keep_alive();
if self.conn.is_write_closed() {
self.close();
}
}
pub(crate) fn into_inner(self) -> (I, Bytes, D) {
let (io, buf) = self.conn.into_inner();
(io, buf, self.dispatch)
}
/// Run this dispatcher until HTTP says this connection is done,
/// but don't call `AsyncWrite::shutdown` on the underlying IO.
///
/// This is useful for old-style HTTP upgrades, but ignores
/// newer-style upgrade API.
pub(crate) fn poll_without_shutdown(
&mut self,
cx: &mut task::Context<'_>,
) -> Poll<crate::Result<()>>
where
Self: Unpin,
{
Pin::new(self).poll_catch(cx, false).map_ok(|ds| {
if let Dispatched::Upgrade(pending) = ds {
pending.manual();
}
})
}
fn poll_catch(
&mut self,
cx: &mut task::Context<'_>,
should_shutdown: bool,
) -> Poll<crate::Result<Dispatched>> {
Poll::Ready(ready!(self.poll_inner(cx, should_shutdown)).or_else(|e| {
// An error means we're shutting down either way.
// We just try to give the error to the user,
// and close the connection with an Ok. If we
// cannot give it to the user, then return the Err.
self.dispatch.recv_msg(Err(e))?;
Ok(Dispatched::Shutdown)
}))
}
fn poll_inner(
&mut self,
cx: &mut task::Context<'_>,
should_shutdown: bool,
) -> Poll<crate::Result<Dispatched>> {
T::update_date();
ready!(self.poll_loop(cx))?;
if self.is_done() {
if let Some(pending) = self.conn.pending_upgrade() {
self.conn.take_error()?;
return Poll::Ready(Ok(Dispatched::Upgrade(pending)));
} else if should_shutdown {
ready!(self.conn.poll_shutdown(cx)).map_err(crate::Error::new_shutdown)?;
}
self.conn.take_error()?;
Poll::Ready(Ok(Dispatched::Shutdown))
} else {
Poll::Pending
}
}
fn poll_loop(&mut self, cx: &mut task::Context<'_>) -> Poll<crate::Result<()>> {
// Limit the looping on this connection, in case it is ready far too
// often, so that other futures don't starve.
//
// 16 was chosen arbitrarily, as that is number of pipelined requests
// benchmarks often use. Perhaps it should be a config option instead.
for _ in 0..16 {
let _ = self.poll_read(cx)?;
let _ = self.poll_write(cx)?;
let _ = self.poll_flush(cx)?;
// This could happen if reading paused before blocking on IO,
// such as getting to the end of a framed message, but then
// writing/flushing set the state back to Init. In that case,
// if the read buffer still had bytes, we'd want to try poll_read
// again, or else we wouldn't ever be woken up again.
//
// Using this instead of task::current() and notify() inside
// the Conn is noticeably faster in pipelined benchmarks.
if !self.conn.wants_read_again() {
//break;
return Poll::Ready(Ok(()));
}
}
trace!("poll_loop yielding (self = {:p})", self);
task::yield_now(cx).map(|never| match never {})
}
fn poll_read(&mut self, cx: &mut task::Context<'_>) -> Poll<crate::Result<()>> {
loop {
if self.is_closing {
return Poll::Ready(Ok(()));
} else if self.conn.can_read_head() {
ready!(self.poll_read_head(cx))?;
} else if let Some(mut body) = self.body_tx.take() {
if self.conn.can_read_body() {
match body.poll_ready(cx) {
Poll::Ready(Ok(())) => (),
Poll::Pending => {
self.body_tx = Some(body);
return Poll::Pending;
}
Poll::Ready(Err(_canceled)) => {
// user doesn't care about the body
// so we should stop reading
trace!("body receiver dropped before eof, draining or closing");
self.conn.poll_drain_or_close_read(cx);
continue;
}
}
match self.conn.poll_read_body(cx) {
Poll::Ready(Some(Ok(chunk))) => match body.try_send_data(chunk) {
Ok(()) => {
self.body_tx = Some(body);
}
Err(_canceled) => {
if self.conn.can_read_body() {
trace!("body receiver dropped before eof, closing");
self.conn.close_read();
}
}
},
Poll::Ready(None) => {
// just drop, the body will close automatically
}
Poll::Pending => {
self.body_tx = Some(body);
return Poll::Pending;
}
Poll::Ready(Some(Err(e))) => {
body.send_error(crate::Error::new_body(e));
}
}
} else {
// just drop, the body will close automatically
}
} else {
return self.conn.poll_read_keep_alive(cx);
}
}
}
fn poll_read_head(&mut self, cx: &mut task::Context<'_>) -> Poll<crate::Result<()>> {
// can dispatch receive, or does it still care about, an incoming message?
match ready!(self.dispatch.poll_ready(cx)) {
Ok(()) => (),
Err(()) => {
trace!("dispatch no longer receiving messages");
self.close();
return Poll::Ready(Ok(()));
}
}
// dispatch is ready for a message, try to read one
match ready!(self.conn.poll_read_head(cx)) {
Some(Ok((mut head, body_len, wants))) => {
let body = match body_len {
DecodedLength::ZERO => Body::empty(),
other => {
let (tx, rx) = Body::new_channel(other, wants.contains(Wants::EXPECT));
self.body_tx = Some(tx);
rx
}
};
if wants.contains(Wants::UPGRADE) {
let upgrade = self.conn.on_upgrade();
debug_assert!(!upgrade.is_none(), "empty upgrade");
debug_assert!(head.extensions.get::<OnUpgrade>().is_none(), "OnUpgrade already set");
head.extensions.insert(upgrade);
}
self.dispatch.recv_msg(Ok((head, body)))?;
Poll::Ready(Ok(()))
}
Some(Err(err)) => {
debug!("read_head error: {}", err);
self.dispatch.recv_msg(Err(err))?;
// if here, the dispatcher gave the user the error
// somewhere else. we still need to shutdown, but
// not as a second error.
self.close();
Poll::Ready(Ok(()))
}
None => {
// read eof, the write side will have been closed too unless
// allow_read_close was set to true, in which case just do
// nothing...
debug_assert!(self.conn.is_read_closed());
if self.conn.is_write_closed() {
self.close();
}
Poll::Ready(Ok(()))
}
}
}
fn poll_write(&mut self, cx: &mut task::Context<'_>) -> Poll<crate::Result<()>> {
loop {
if self.is_closing {
return Poll::Ready(Ok(()));
} else if self.body_rx.is_none()
&& self.conn.can_write_head()
&& self.dispatch.should_poll()
{
if let Some(msg) = ready!(Pin::new(&mut self.dispatch).poll_msg(cx)) {
let (head, mut body) = msg.map_err(crate::Error::new_user_service)?;
// Check if the body knows its full data immediately.
//
// If so, we can skip a bit of bookkeeping that streaming
// bodies need to do.
if let Some(full) = crate::body::take_full_data(&mut body) {
self.conn.write_full_msg(head, full);
return Poll::Ready(Ok(()));
}
let body_type = if body.is_end_stream() {
self.body_rx.set(None);
None
} else {
let btype = body
.size_hint()
.exact()
.map(BodyLength::Known)
.or_else(|| Some(BodyLength::Unknown));
self.body_rx.set(Some(body));
btype
};
self.conn.write_head(head, body_type);
} else {
self.close();
return Poll::Ready(Ok(()));
}
} else if !self.conn.can_buffer_body() {
ready!(self.poll_flush(cx))?;
} else {
// A new scope is needed :(
if let (Some(mut body), clear_body) =
OptGuard::new(self.body_rx.as_mut()).guard_mut()
{
debug_assert!(!*clear_body, "opt guard defaults to keeping body");
if !self.conn.can_write_body() {
trace!(
"no more write body allowed, user body is_end_stream = {}",
body.is_end_stream(),
);
*clear_body = true;
continue;
}
let item = ready!(body.as_mut().poll_data(cx));
if let Some(item) = item {
let chunk = item.map_err(|e| {
*clear_body = true;
crate::Error::new_user_body(e)
})?;
let eos = body.is_end_stream();
if eos {
*clear_body = true;
if chunk.remaining() == 0 {
trace!("discarding empty chunk");
self.conn.end_body()?;
} else {
self.conn.write_body_and_end(chunk);
}
} else {
if chunk.remaining() == 0 {
trace!("discarding empty chunk");
continue;
}
self.conn.write_body(chunk);
}
} else {
*clear_body = true;
self.conn.end_body()?;
}
} else {
return Poll::Pending;
}
}
}
}
fn poll_flush(&mut self, cx: &mut task::Context<'_>) -> Poll<crate::Result<()>> {
self.conn.poll_flush(cx).map_err(|err| {
debug!("error writing: {}", err);
crate::Error::new_body_write(err)
})
}
fn close(&mut self) {
self.is_closing = true;
self.conn.close_read();
self.conn.close_write();
}
fn is_done(&self) -> bool {
if self.is_closing {
return true;
}
let read_done = self.conn.is_read_closed();
if !T::should_read_first() && read_done {
// a client that cannot read may was well be done.
true
} else {
let write_done = self.conn.is_write_closed()
|| (!self.dispatch.should_poll() && self.body_rx.is_none());
read_done && write_done
}
}
}
impl<D, Bs, I, T> Future for Dispatcher<D, Bs, I, T>
where
D: Dispatch<
PollItem = MessageHead<T::Outgoing>,
PollBody = Bs,
RecvItem = MessageHead<T::Incoming>,
> + Unpin,
D::PollError: Into<Box<dyn StdError + Send + Sync>>,
I: AsyncRead + AsyncWrite + Unpin,
T: Http1Transaction + Unpin,
Bs: HttpBody + 'static,
Bs::Error: Into<Box<dyn StdError + Send + Sync>>,
{
type Output = crate::Result<Dispatched>;
#[inline]
fn poll(mut self: Pin<&mut Self>, cx: &mut task::Context<'_>) -> Poll<Self::Output> {
self.poll_catch(cx, true)
}
}
// ===== impl OptGuard =====
/// A drop guard to allow a mutable borrow of an Option while being able to
/// set whether the `Option` should be cleared on drop.
struct OptGuard<'a, T>(Pin<&'a mut Option<T>>, bool);
impl<'a, T> OptGuard<'a, T> {
fn new(pin: Pin<&'a mut Option<T>>) -> Self {
OptGuard(pin, false)
}
fn guard_mut(&mut self) -> (Option<Pin<&mut T>>, &mut bool) {
(self.0.as_mut().as_pin_mut(), &mut self.1)
}
}
impl<'a, T> Drop for OptGuard<'a, T> {
fn drop(&mut self) {
if self.1 {
self.0.set(None);
}
}
}
// ===== impl Server =====
cfg_server! {
impl<S, B> Server<S, B>
where
S: HttpService<B>,
{
pub(crate) fn new(service: S) -> Server<S, B> {
Server {
in_flight: Box::pin(None),
service,
}
}
pub(crate) fn into_service(self) -> S {
self.service
}
}
// Service is never pinned
impl<S: HttpService<B>, B> Unpin for Server<S, B> {}
impl<S, Bs> Dispatch for Server<S, Body>
where
S: HttpService<Body, ResBody = Bs>,
S::Error: Into<Box<dyn StdError + Send + Sync>>,
Bs: HttpBody,
{
type PollItem = MessageHead<http::StatusCode>;
type PollBody = Bs;
type PollError = S::Error;
type RecvItem = RequestHead;
fn poll_msg(
mut self: Pin<&mut Self>,
cx: &mut task::Context<'_>,
) -> Poll<Option<Result<(Self::PollItem, Self::PollBody), Self::PollError>>> {
let mut this = self.as_mut();
let ret = if let Some(ref mut fut) = this.in_flight.as_mut().as_pin_mut() {
let resp = ready!(fut.as_mut().poll(cx)?);
let (parts, body) = resp.into_parts();
let head = MessageHead {
version: parts.version,
subject: parts.status,
headers: parts.headers,
extensions: parts.extensions,
};
Poll::Ready(Some(Ok((head, body))))
} else {
unreachable!("poll_msg shouldn't be called if no inflight");
};
// Since in_flight finished, remove it
this.in_flight.set(None);
ret
}
fn recv_msg(&mut self, msg: crate::Result<(Self::RecvItem, Body)>) -> crate::Result<()> {
let (msg, body) = msg?;
let mut req = Request::new(body);
*req.method_mut() = msg.subject.0;
*req.uri_mut() = msg.subject.1;
*req.headers_mut() = msg.headers;
*req.version_mut() = msg.version;
*req.extensions_mut() = msg.extensions;
let fut = self.service.call(req);
self.in_flight.set(Some(fut));
Ok(())
}
fn poll_ready(&mut self, cx: &mut task::Context<'_>) -> Poll<Result<(), ()>> {
if self.in_flight.is_some() {
Poll::Pending
} else {
self.service.poll_ready(cx).map_err(|_e| {
// FIXME: return error value.
trace!("service closed");
})
}
}
fn should_poll(&self) -> bool {
self.in_flight.is_some()
}
}
}
// ===== impl Client =====
cfg_client! {
impl<B> Client<B> {
pub(crate) fn new(rx: ClientRx<B>) -> Client<B> {
Client {
callback: None,
rx,
rx_closed: false,
}
}
}
impl<B> Dispatch for Client<B>
where
B: HttpBody,
{
type PollItem = RequestHead;
type PollBody = B;
type PollError = crate::common::Never;
type RecvItem = crate::proto::ResponseHead;
fn poll_msg(
mut self: Pin<&mut Self>,
cx: &mut task::Context<'_>,
) -> Poll<Option<Result<(Self::PollItem, Self::PollBody), crate::common::Never>>> {
let mut this = self.as_mut();
debug_assert!(!this.rx_closed);
match this.rx.poll_recv(cx) {
Poll::Ready(Some((req, mut cb))) => {
// check that future hasn't been canceled already
match cb.poll_canceled(cx) {
Poll::Ready(()) => {
trace!("request canceled");
Poll::Ready(None)
}
Poll::Pending => {
let (parts, body) = req.into_parts();
let head = RequestHead {
version: parts.version,
subject: crate::proto::RequestLine(parts.method, parts.uri),
headers: parts.headers,
extensions: parts.extensions,
};
this.callback = Some(cb);
Poll::Ready(Some(Ok((head, body))))
}
}
}
Poll::Ready(None) => {
// user has dropped sender handle
trace!("client tx closed");
this.rx_closed = true;
Poll::Ready(None)
}
Poll::Pending => Poll::Pending,
}
}
fn recv_msg(&mut self, msg: crate::Result<(Self::RecvItem, Body)>) -> crate::Result<()> {
match msg {
Ok((msg, body)) => {
if let Some(cb) = self.callback.take() {
let res = msg.into_response(body);
cb.send(Ok(res));
Ok(())
} else {
// Getting here is likely a bug! An error should have happened
// in Conn::require_empty_read() before ever parsing a
// full message!
Err(crate::Error::new_unexpected_message())
}
}
Err(err) => {
if let Some(cb) = self.callback.take() {
cb.send(Err((err, None)));
Ok(())
} else if !self.rx_closed {
self.rx.close();
if let Some((req, cb)) = self.rx.try_recv() {
trace!("canceling queued request with connection error: {}", err);
// in this case, the message was never even started, so it's safe to tell
// the user that the request was completely canceled
cb.send(Err((crate::Error::new_canceled().with(err), Some(req))));
Ok(())
} else {
Err(err)
}
} else {
Err(err)
}
}
}
}
fn poll_ready(&mut self, cx: &mut task::Context<'_>) -> Poll<Result<(), ()>> {
match self.callback {
Some(ref mut cb) => match cb.poll_canceled(cx) {
Poll::Ready(()) => {
trace!("callback receiver has dropped");
Poll::Ready(Err(()))
}
Poll::Pending => Poll::Ready(Ok(())),
},
None => Poll::Ready(Err(())),
}
}
fn should_poll(&self) -> bool {
self.callback.is_none()
}
}
}
#[cfg(test)]
mod tests {
use super::*;
use crate::proto::h1::ClientTransaction;
use std::time::Duration;
#[test]
fn client_read_bytes_before_writing_request() {
let _ = pretty_env_logger::try_init();
tokio_test::task::spawn(()).enter(|cx, _| {
let (io, mut handle) = tokio_test::io::Builder::new().build_with_handle();
// Block at 0 for now, but we will release this response before
// the request is ready to write later...
let (mut tx, rx) = crate::client::dispatch::channel();
let conn = Conn::<_, bytes::Bytes, ClientTransaction>::new(io);
let mut dispatcher = Dispatcher::new(Client::new(rx), conn);
// First poll is needed to allow tx to send...
assert!(Pin::new(&mut dispatcher).poll(cx).is_pending());
// Unblock our IO, which has a response before we've sent request!
//
handle.read(b"HTTP/1.1 200 OK\r\n\r\n");
let mut res_rx = tx
.try_send(crate::Request::new(crate::Body::empty()))
.unwrap();
tokio_test::assert_ready_ok!(Pin::new(&mut dispatcher).poll(cx));
let err = tokio_test::assert_ready_ok!(Pin::new(&mut res_rx).poll(cx))
.expect_err("callback should send error");
match (err.0.kind(), err.1) {
(&crate::error::Kind::Canceled, Some(_)) => (),
other => panic!("expected Canceled, got {:?}", other),
}
});
}
#[tokio::test]
async fn client_flushing_is_not_ready_for_next_request() {
let _ = pretty_env_logger::try_init();
let (io, _handle) = tokio_test::io::Builder::new()
.write(b"POST / HTTP/1.1\r\ncontent-length: 4\r\n\r\n")
.read(b"HTTP/1.1 200 OK\r\ncontent-length: 0\r\n\r\n")
.wait(std::time::Duration::from_secs(2))
.build_with_handle();
let (mut tx, rx) = crate::client::dispatch::channel();
let mut conn = Conn::<_, bytes::Bytes, ClientTransaction>::new(io);
conn.set_write_strategy_queue();
let dispatcher = Dispatcher::new(Client::new(rx), conn);
let _dispatcher = tokio::spawn(async move { dispatcher.await });
let req = crate::Request::builder()
.method("POST")
.body(crate::Body::from("reee"))
.unwrap();
let res = tx.try_send(req).unwrap().await.expect("response");
drop(res);
assert!(!tx.is_ready());
}
#[tokio::test]
async fn body_empty_chunks_ignored() {
let _ = pretty_env_logger::try_init();
let io = tokio_test::io::Builder::new()
// no reading or writing, just be blocked for the test...
.wait(Duration::from_secs(5))
.build();
let (mut tx, rx) = crate::client::dispatch::channel();
let conn = Conn::<_, bytes::Bytes, ClientTransaction>::new(io);
let mut dispatcher = tokio_test::task::spawn(Dispatcher::new(Client::new(rx), conn));
// First poll is needed to allow tx to send...
assert!(dispatcher.poll().is_pending());
let body = {
let (mut tx, body) = crate::Body::channel();
tx.try_send_data("".into()).unwrap();
body
};
let _res_rx = tx.try_send(crate::Request::new(body)).unwrap();
// Ensure conn.write_body wasn't called with the empty chunk.
// If it is, it will trigger an assertion.
assert!(dispatcher.poll().is_pending());
}
}
