simpler_proxy.rs

use std::error::Error;

use std::net::{Shutdown, TcpListener, TcpStream};
use std::thread::spawn;

fn main() {
    let server = TcpListener::bind("127.0.0.1:15432").unwrap();
    for client in server.incoming() {
        let client = client.unwrap();
        client.set_nodelay(true).unwrap();
        println!("New conn...");

        spawn(move || {
            handle_connection(client).unwrap();
        });
    }
}

fn handle_connection(mut client: TcpStream) -> Result<(), Box<dyn Error>> {
    let mut upstream = TcpStream::connect("127.0.0.1:5432")?;
    upstream.set_nodelay(true)?;

    let regexes = vec![
        Regex::new(r"^select \* from cmdb where sys_id = (?P<p1>'[a-z0-9]{32}');$").unwrap()
    ];
    let mut cache = Cache::new(&regexes);
    let mut dummy_cache = Cache::new(&regexes);

    let mut client_clone = client.try_clone()?;
    let mut upstream_clone = upstream.try_clone()?;

    let t1 = spawn(move || {
        std::io::copy(&mut client, &mut upstream)?;
        upstream.shutdown(Shutdown::Both)
    });
    let t2 = spawn(move || {
        std::io::copy(&mut upstream_clone, &mut client_clone)?;
        client_clone.shutdown(Shutdown::Both)
    });

    t1.join().unwrap()?;
    t2.join().unwrap()?;

    Ok(())
}