smol/examples/hyper-client.rs

145 lines
4.2 KiB
Rust

//! An HTTP+TLS client based on `hyper` and `async-native-tls`.
//!
//! Run with:
//!
//! ```
//! cargo run --example hyper-client
//! ```
use std::convert::TryInto;
use std::pin::Pin;
use std::task::{Context, Poll};
use anyhow::{bail, Context as _, Result};
use async_native_tls::TlsStream;
use http_body_util::{BodyStream, Empty};
use hyper::body::Incoming;
use hyper::{Request, Response};
use macro_rules_attribute::apply;
use smol::{io, net::TcpStream, prelude::*, Executor};
use smol_hyper::rt::FuturesIo;
use smol_macros::main;
/// Sends a request and fetches the response.
async fn fetch(
ex: &Executor<'static>,
req: Request<Empty<&'static [u8]>>,
) -> Result<Response<Incoming>> {
// Connect to the HTTP server.
let io = {
let host = req.uri().host().context("cannot parse host")?;
match req.uri().scheme_str() {
Some("http") => {
let stream = {
let port = req.uri().port_u16().unwrap_or(80);
TcpStream::connect((host, port)).await?
};
SmolStream::Plain(stream)
}
Some("https") => {
// In case of HTTPS, establish a secure TLS connection first.
let stream = {
let port = req.uri().port_u16().unwrap_or(443);
TcpStream::connect((host, port)).await?
};
let stream = async_native_tls::connect(host, stream).await?;
SmolStream::Tls(stream)
}
scheme => bail!("unsupported scheme: {:?}", scheme),
}
};
// Spawn the HTTP/1 connection.
let (mut sender, conn) = hyper::client::conn::http1::handshake(FuturesIo::new(io)).await?;
ex.spawn(async move {
if let Err(e) = conn.await {
println!("Connection failed: {:?}", e);
}
})
.detach();
// Get the result
let result = sender.send_request(req).await?;
Ok(result)
}
#[apply(main!)]
async fn main(ex: &Executor<'static>) -> Result<()> {
// Create a request.
let url: hyper::Uri = "https://www.rust-lang.org".try_into()?;
let req = Request::builder()
.header(
hyper::header::HOST,
url.authority().unwrap().clone().as_str(),
)
.uri(url)
.body(Empty::new())?;
// Fetch the response.
let resp = fetch(ex, req).await?;
println!("{:#?}", resp);
// Read the message body.
let body: Vec<u8> = BodyStream::new(resp.into_body())
.try_fold(Vec::new(), |mut body, chunk| {
if let Some(chunk) = chunk.data_ref() {
body.extend_from_slice(chunk);
}
Ok(body)
})
.await?;
println!("{}", String::from_utf8_lossy(&body));
Ok(())
}
/// A TCP or TCP+TLS connection.
enum SmolStream {
/// A plain TCP connection.
Plain(TcpStream),
/// A TCP connection secured by TLS.
Tls(TlsStream<TcpStream>),
}
impl AsyncRead for SmolStream {
fn poll_read(
mut self: Pin<&mut Self>,
cx: &mut Context<'_>,
buf: &mut [u8],
) -> Poll<io::Result<usize>> {
match &mut *self {
SmolStream::Plain(stream) => Pin::new(stream).poll_read(cx, buf),
SmolStream::Tls(stream) => Pin::new(stream).poll_read(cx, buf),
}
}
}
impl AsyncWrite for SmolStream {
fn poll_write(
mut self: Pin<&mut Self>,
cx: &mut Context<'_>,
buf: &[u8],
) -> Poll<io::Result<usize>> {
match &mut *self {
SmolStream::Plain(stream) => Pin::new(stream).poll_write(cx, buf),
SmolStream::Tls(stream) => Pin::new(stream).poll_write(cx, buf),
}
}
fn poll_close(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<io::Result<()>> {
match &mut *self {
SmolStream::Plain(stream) => Pin::new(stream).poll_close(cx),
SmolStream::Tls(stream) => Pin::new(stream).poll_close(cx),
}
}
fn poll_flush(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<io::Result<()>> {
match &mut *self {
SmolStream::Plain(stream) => Pin::new(stream).poll_flush(cx),
SmolStream::Tls(stream) => Pin::new(stream).poll_flush(cx),
}
}
}