Why is the client not connecting to my tcp server? - windows

Question

I'm unable to connect to my server with the client eventhough. My laptop acts as the client and my PC acts as the server, they are connected to the same wifi. I tried turning the windows firewall off but it didn't help. This is the error code my laptop (client) is getting: Error: Os { code: 10061, kind: ConnectionRefused, message: "No connection could be made because the target machine actively refused it." }
Client code that runs on the laptop:
use std::io::prelude::*;
use std::net::TcpStream;
fn main() -> std::io::Result<()> {
let mut stream = TcpStream::connect("localhost:8080")?;
stream.write(&[1])?;
stream.read(&mut [0; 128])?;
Ok(())
} // the stream is closed here
Server code that runs on the PC:
use std::net::{TcpListener, TcpStream};
use std::io::{Read, Write};
use std::io::{BufReader,BufWriter};
fn handle_client(stream: TcpStream) {
// ...
let mut reader = BufReader::new(&stream);
let mut response = String::new();
reader.read_to_string(&mut response).unwrap();
println!("{}", response);
}
fn main() -> std::io::Result<()> {
let listener = TcpListener::bind("0.0.0.0:8080")?;
// accept connections and process them serially
for stream in listener.incoming() {
handle_client(stream?);
}
Ok(())
}

Answer 1

You need to specify hostname or IP of the other machine instead of localhost. You can find it by hand and hardcode it. If you want your program to find the other machine on your local network automatically, that's a complex annoying problem which itself is way bigger than what you're trying to do here.
After you connect both machines, you'll find that your programs gets stuck.
That's because read_to_string never stops reading until the connection is entirely closed. TCP is not message-based, so the other side will not read a single write, it will keep reading and waiting until the other side hangs up. You will need to devise a protocol that knows exactly how many bytes it needs to read, before reading them, and won't ask for a byte more (e.g. send length of a string before the string).