CODEWITHSUNDEEP
tcprust
Count Zero
Count Zero

Reputation: 555

BufWriter::write() doesn't write bytes to TcpStream

I've written an echo server and client in Rust. Here is my code:

Server:

use std::net::{TcpListener, TcpStream};
use std::thread;
use std::io::Write;
use std::io::BufReader;
use std::io::BufRead;
use std::io::BufWriter;

fn handle_connection(stream: TcpStream) {
    let stream_clone = stream.try_clone().unwrap();
    let mut reader = BufReader::new(stream);
    let mut writer = BufWriter::new(stream_clone);
    loop {
        let mut s = String::new();
        reader.read_line(&mut s).unwrap();
        writer.write(s.as_bytes()).unwrap();
    }
}

fn main() {
    let listener = TcpListener::bind("127.0.0.1:8888")
        .unwrap();
    for stream in listener.incoming() {
        thread::spawn(move || {
            handle_connection(stream.unwrap());
        });
    }
}

Client:

use std::net::TcpStream;
use std::io;
use std::io::Write;
use std::io::BufReader;
use std::io::BufRead;
use std::io::BufWriter;

fn main() {
    let stream = TcpStream::connect("127.0.0.1:8888")
        .unwrap();
    let stream_clone = stream.try_clone().unwrap();
    let mut reader = BufReader::new(stream);
    let mut writer = BufWriter::new(stream_clone);
    loop {
        let mut s = String::new();
        let mut response = String::new();
        io::stdin().read_line(&mut s).unwrap();
        writer.write(s.as_bytes()).unwrap();
        reader.read_line(&mut response).unwrap();
        println!("{}", response.trim());
    }
}

When I test the code, the server don't respond at all. My guess is that something is wrong with the write method. Am I right, or is there another reason?

Upvotes: 2

Views: 1965

Answers (1)

Дмитрий Шулицкий
Дмитрий Шулицкий

Reputation: 576

You need to flush the buffers: writer.flush()

Fixed server:

use std::net::{TcpListener, TcpStream};
use std::thread;
use std::io::Write;
use std::io::BufReader;
use std::io::BufRead;
use std::io::BufWriter;

fn handle_connection(stream: TcpStream) {
    let stream_clone = stream.try_clone().unwrap();
    let mut reader = BufReader::new(stream);
    let mut writer = BufWriter::new(stream_clone);
    loop {
        let mut s = String::new();
        reader.read_line(&mut s).unwrap();
        writer.write(s.as_bytes()).unwrap();
        writer.flush().unwrap();
    }
}

fn main() {
    let listener = TcpListener::bind("127.0.0.1:8888")
        .unwrap();
    for stream in listener.incoming() {
        thread::spawn(move || {
            handle_connection(stream.unwrap());
        });
    }
}

Client:

use std::net::TcpStream;
use std::io;
use std::io::Write;
use std::io::BufReader;
use std::io::BufRead;
use std::io::BufWriter;

fn main() {
    let stream = TcpStream::connect("127.0.0.1:8888")
        .unwrap();
    let stream_clone = stream.try_clone().unwrap();
    let mut reader = BufReader::new(stream);
    let mut writer = BufWriter::new(stream_clone);
    loop {
        let mut s = String::new();
        let mut response = String::new();
        io::stdin().read_line(&mut s).unwrap();
        writer.write(s.as_bytes()).unwrap();
        writer.flush().unwrap();
        reader.read_line(&mut response).unwrap();
        println!("{}", response.trim());
    }
}

Upvotes: 5

Related Questions