lox_cli/src/client_net.rs

/*! The networking methods for our client components to call. In
particular, this file provides a send() method to handle connecting
to a server process and sending it data. */

use tokio::io::{AsyncReadExt, AsyncWriteExt};
use tokio::net::TcpStream;

// may need to change strings to byte vectors in the future
pub async fn send(addr: String, payload: Vec<u8>) -> Vec<u8> {
    let mut stream = TcpStream::connect(&addr)
        .await
        .expect("Failed to create TcpStream");

    // send number of bytes in payload
    let payload_size = usize::to_be_bytes(payload.len());
    stream
        .write_all(&payload_size)
        .await
        .expect("Failed to write number of bytes to listen for");

    // send data
    stream
        .write_all(&payload)
        .await
        .expect("Failed to write data to stream");

    // get number of bytes in response
    let mut nbuf: [u8; 8] = [0; 8];
    stream
        .read(&mut nbuf)
        .await
        .expect("Failed to get number of bytes to read");
    let n = usize::from_be_bytes(nbuf);

    if n == 0 {
        return vec![0; 0];
    }

    // receive response
    let mut buf = vec![0; n];
    stream
        .read(&mut buf)
        .await
        .expect("Failed to read data from socket");

    buf
}