touche

Crates.io	touche
lib.rs	touche
version	0.0.10
source	src
created_at	2022-07-25 19:05:59.077584
updated_at	2024-08-23 01:57:45.873941
description	Synchronous HTTP library
homepage
repository	https://github.com/reu/touche
max_upload_size
id	632773
size	161,259

Rodrigo Navarro (reu)

documentation

README

touché

Touché is a low level but fully featured HTTP 1.0/1.1 library.

It tries to mimic hyper, but with a synchronous API.

For now only the server API is implemented.

Hello world

use touche::{Response, Server, StatusCode};

fn main() -> std::io::Result<()> {
    Server::bind("0.0.0.0:4444").serve(|_req| {
        Response::builder()
            .status(StatusCode::OK)
            .body("Hello World")
    })
}

Features

HTTP Server (thread per connection model, backed by a thread pool)
Non buffered (streaming) requests and response bodies
HTTP/1.1 pipelining
TLS
Upgrade connections
Trailers headers
100 continue expectation
Unix sockets servers

Comparison with Hyper

Touché shares a lot of similarities with Hyper:

"Low level"
Uses the http crate to represent HTTP related types
Allows fine-grained implementations of streaming HTTP bodies

But also has some key differences:

It is synchronous
Uses Vec<u8> to represent bytes instead of Bytes
Doesn't support HTTP 2 (and probably never will)

Handling persistent connections with non blocking IO

Connection-per-thread web servers are notorious bad with persistent connections like websockets or event streams. This is primarily because the thread gets locked to the connection until it is closed.

One solution to this problem is to handle such connections with non-blocking IO. By doing so, the server thread becomes available for other connections.

The following example demonstrates a single-threaded touché server that handles websockets upgrades to a Tokio runtime.

use std::{error::Error, sync::Arc};

use futures::{stream::StreamExt, SinkExt};
use tokio::{net::TcpStream, runtime};
use tokio_tungstenite::{tungstenite::protocol::Role, WebSocketStream};
use touche::{upgrade::Upgrade, Body, Connection, Request, Server};

fn main() -> std::io::Result<()> {
    let runtime = Arc::new(runtime::Builder::new_multi_thread().enable_all().build()?);

    Server::builder()
        .max_threads(1)
        .bind("0.0.0.0:4444")
        .serve(move |req: Request<Body>| {
            let runtime = runtime.clone();

            let res = tungstenite::handshake::server::create_response(&req.map(|_| ()))?;

            Ok::<_, Box<dyn Error + Send + Sync>>(res.upgrade(move |stream: Connection| {
                let stream = stream.downcast::<std::net::TcpStream>().unwrap();
                stream.set_nonblocking(true).unwrap();

                runtime.spawn(async move {
                    let stream = TcpStream::from_std(stream).unwrap();
                    let mut ws = WebSocketStream::from_raw_socket(stream, Role::Server, None).await;

                    while let Some(Ok(msg)) = ws.next().await {
                        if msg.is_text() && ws.send(msg).await.is_err() {
                            break;
                        }
                    }
                });
            }))
        })
}

Other examples

Chunked response

use std::{error::Error, thread};

use touche::{Body, Response, Server, StatusCode};

fn main() -> std::io::Result<()> {
    Server::bind("0.0.0.0:4444").serve(|_req| {
        let (channel, body) = Body::channel();

        thread::spawn(move || {
            channel.send("chunk1").unwrap();
            channel.send("chunk2").unwrap();
            channel.send("chunk3").unwrap();
        });

        Response::builder()
            .status(StatusCode::OK)
            .body(body)
    })
}

Streaming files

use std::{fs, io};

use touche::{Body, Response, Server, StatusCode};

fn main() -> std::io::Result<()> {
    Server::bind("0.0.0.0:4444").serve(|_req| {
        let file = fs::File::open("./examples/file.rs")?;
        Ok::<_, io::Error>(
            Response::builder()
                .status(StatusCode::OK)
                .body(Body::try_from(file)?)
                .unwrap(),
        )
    })
}

Naive routing with pattern matching

use touche::{body::HttpBody, Body, Method, Request, Response, Server, StatusCode};

fn main() -> std::io::Result<()> {
    Server::builder()
        .bind("0.0.0.0:4444")
        .serve(|req: Request<Body>| {
            match (req.method(), req.uri().path()) {
                (_, "/") => Response::builder()
                    .status(StatusCode::OK)
                    .body(Body::from("Usage: curl -d hello localhost:4444/echo\n")),

                // Responds with the same payload
                (&Method::POST, "/echo") => Response::builder()
                    .status(StatusCode::OK)
                    .body(req.into_body()),

                // Responds with the reversed payload
                (&Method::POST, "/reverse") => {
                    let body = req.into_body().into_bytes().unwrap_or_default();

                    match std::str::from_utf8(&body) {
                        Ok(message) => Response::builder()
                            .status(StatusCode::OK)
                            .body(message.chars().rev().collect::<String>().into()),

                        Err(err) => Response::builder()
                            .status(StatusCode::BAD_REQUEST)
                            .body(err.to_string().into()),
                    }
                }

                _ => Response::builder()
                    .status(StatusCode::NOT_FOUND)
                    .body(Body::empty()),
            }
        })
}

Response upgrades

use std::io::{BufRead, BufReader, BufWriter, Write};

use touche::{header, upgrade::Upgrade, Body, Connection, Response, Server, StatusCode};

fn main() -> std::io::Result<()> {
    Server::bind("0.0.0.0:4444").serve(|_req| {
        Response::builder()
            .status(StatusCode::SWITCHING_PROTOCOLS)
            .header(header::UPGRADE, "line-protocol")
            .upgrade(|stream: Connection| {
                let reader = BufReader::new(stream.clone());
                let mut writer = BufWriter::new(stream);

                // Just a simple protocol that will echo every line sent
                for line in reader.lines() {
                    match line {
                        Ok(line) if line.as_str() == "quit" => break,
                        Ok(line) => {
                            writer.write_all(format!("{line}\n").as_bytes());
                            writer.flush();
                        }
                        Err(_err) => break,
                    };
                }
            })
            .body(Body::empty())
    })
}

You can find other examples in the examples directory.

Performance

While the primary focus is having a simple and readable implementation, the library shows some decent performance.

A simple benchmark of the hello_world.rs example gives the following result:

$ cat /proc/cpuinfo | grep name | uniq
model name      : AMD Ryzen 5 5600G with Radeon Graphics

$ wrk --latency -t6 -c 200 -d 10s http://localhost:4444
Running 10s test @ http://localhost:4444
  6 threads and 200 connections
  Thread Stats   Avg      Stdev     Max   +/- Stdev
    Latency   153.37us  391.20us  19.41ms   99.37%
    Req/Sec    76.11k    13.21k   89.14k    82.67%
  Latency Distribution
     50%  126.00us
     75%  160.00us
     90%  209.00us
     99%  360.00us
  4544074 requests in 10.01s, 225.35MB read
Requests/sec: 454157.11
Transfer/sec:     22.52MB

The result is on par with Hyper's hello world running on the same machine.

Disclaimer

This library is by no means a critique to Hyper or to async Rust. I really love both of them.

The main motivation I had to write this library was to be able to introduce Rust to my co-workers (which are mainly web developers). A synchronous library is way more beginner friendly than an async one, and by having an API that ressembles the "canonical" HTTP Rust library, people can learn Rust concepts in a easier way before adventuring through Hyper and async.

Commit count: 118