tokio-echo.rs

extern crate bytes;
extern crate futures;
extern crate tokio_io;
extern crate tokio_proto;
extern crate tokio_service;

use std::io;
use std::str;
use bytes::BytesMut;
use futures::{future, Future};
use tokio_io::codec::{Encoder, Decoder};
use tokio_io::codec::Framed;
use tokio_io::{AsyncRead, AsyncWrite};
use tokio_proto::pipeline::ServerProto;
use tokio_proto::TcpServer;
use tokio_service::Service;

pub struct LineCodec;

impl Decoder for LineCodec {
    type Item = String;
    type Error = io::Error;

    fn decode(&mut self, buf: &mut BytesMut) -> io::Result<Option<String>> {
        if let Some(i) = buf.iter().position(|&b| b == b'\n') {
            let line = buf.split_to(i);
            buf.split_to(1);
            match str::from_utf8(&line) {
                Ok(s) => Ok(Some(s.to_string())),
                Err(_) => Err(io::Error::new(io::ErrorKind::Other, "invalid UTF-8")),
            }
        } else {
            return Ok(None);
        }
    }
}

impl Encoder for LineCodec {
    type Item = String;
    type Error = io::Error;

    fn encode(&mut self, msg: String, buf: &mut BytesMut) -> io::Result<()> {
        buf.extend(msg.as_bytes());
        buf.extend(b"\n");
        return Ok(());
    }
}

pub struct LineProto;

impl<T: AsyncRead + AsyncWrite + 'static> ServerProto<T> for LineProto {
    type Request = String;
    type Response = String;
    type Transport = Framed<T, LineCodec>;
    type BindTransport = Result<Self::Transport, io::Error>;

    fn bind_transport(&self, io: T) -> Self::BindTransport {
        return Ok(io.framed(LineCodec));
    }
}

pub struct Echo;

impl Service for Echo {
    type Request = String;
    type Response = String;
    type Error = io::Error;
    type Future = Box<Future<Item = Self::Response, Error = Self::Error>>;
    fn call(&self, req: Self::Request) -> Self::Future {
        Box::new(future::ok(req))
    }
}

fn main() {
    let addr = "0.0.0.0:12345".parse().unwrap();
    let server = TcpServer::new(LineProto, addr);
    server.serve(|| Ok(Echo));
}