tokio/async-await/src/echo_client.rs

#![feature(await_macro, async_await)]

use tokio::async_wait;
use tokio::net::TcpStream;
use tokio::prelude::*;

use std::io;
use std::net::SocketAddr;

const MESSAGES: &[&str] = &[
    "hello",
    "world",
    "one two three",
];

async fn run_client(addr: &SocketAddr) -> io::Result<()> {
    let mut stream = async_wait!(TcpStream::connect(addr))?;

    // Buffer to read into
    let mut buf = [0; 128];

    for msg in MESSAGES {
        println!(" > write = {:?}", msg);

        // Write the message to the server
        async_wait!(stream.write_all_async(msg.as_bytes()))?;

        // Read the message back from the server
        async_wait!(stream.read_exact_async(&mut buf[..msg.len()]))?;

        assert_eq!(&buf[..msg.len()], msg.as_bytes());
    }

    Ok(())
}

#[tokio::main]
async fn main() {
    use std::env;

    let addr = env::args().nth(1).unwrap_or("127.0.0.1:8080".to_string());
    let addr = addr.parse::<SocketAddr>().unwrap();

    // Connect to the echo serveer

    match async_wait!(run_client(&addr)) {
        Ok(_) => println!("done."),
        Err(e) => eprintln!("echo client failed; error = {:?}", e),
    }
}