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Diffstat (limited to 'examples/chat-combinator.rs')
-rw-r--r-- | examples/chat-combinator.rs | 138 |
1 files changed, 138 insertions, 0 deletions
diff --git a/examples/chat-combinator.rs b/examples/chat-combinator.rs new file mode 100644 index 00000000..667f0e9a --- /dev/null +++ b/examples/chat-combinator.rs @@ -0,0 +1,138 @@ +//! A chat server that broadcasts a message to all connections. +//! +//! This is a simple line-based server which accepts connections, reads lines +//! from those connections, and broadcasts the lines to all other connected +//! clients. In a sense this is a bit of a "poor man's chat server". +//! +//! You can test this out by running: +//! +//! cargo run --example chat +//! +//! And then in another window run: +//! +//! cargo run --example connect 127.0.0.1:8080 +//! +//! You can run the second command in multiple windows and then chat between the +//! two, seeing the messages from the other client as they're received. For all +//! connected clients they'll all join the same room and see everyone else's +//! messages. + +extern crate futures; +extern crate futures_cpupool; +extern crate tokio; +extern crate tokio_io; + +use std::collections::HashMap; +use std::iter; +use std::env; +use std::io::{Error, ErrorKind, BufReader}; +use std::sync::{Arc, Mutex}; + +use futures::Future; +use futures::future::{self, Executor}; +use futures::stream::{self, Stream}; +use futures_cpupool::CpuPool; +use tokio::net::TcpListener; +use tokio_io::io; +use tokio_io::AsyncRead; + +fn main() { + let addr = env::args().nth(1).unwrap_or("127.0.0.1:8080".to_string()); + let addr = addr.parse().unwrap(); + + // Create the TCP listener we'll accept connections on. + let socket = TcpListener::bind(&addr).unwrap(); + println!("Listening on: {}", addr); + + // This is currently a multi threaded server. + // + // Once the same thread executor lands, transition to single threaded. + let connections = Arc::new(Mutex::new(HashMap::new())); + + let srv = socket.incoming().for_each(move |stream| { + let addr = stream.peer_addr().unwrap(); + + println!("New Connection: {}", addr); + let (reader, writer) = stream.split(); + + // Create a channel for our stream, which other sockets will use to + // send us messages. Then register our address with the stream to send + // data to us. + let (tx, rx) = futures::sync::mpsc::unbounded(); + connections.lock().unwrap().insert(addr, tx); + + // Define here what we do for the actual I/O. That is, read a bunch of + // lines from the socket and dispatch them while we also write any lines + // from other sockets. + let connections_inner = connections.clone(); + let reader = BufReader::new(reader); + + // Model the read portion of this socket by mapping an infinite + // iterator to each line off the socket. This "loop" is then + // terminated with an error once we hit EOF on the socket. + let iter = stream::iter_ok::<_, Error>(iter::repeat(())); + let socket_reader = iter.fold(reader, move |reader, _| { + // Read a line off the socket, failing if we're at EOF + let line = io::read_until(reader, b'\n', Vec::new()); + let line = line.and_then(|(reader, vec)| { + if vec.len() == 0 { + Err(Error::new(ErrorKind::BrokenPipe, "broken pipe")) + } else { + Ok((reader, vec)) + } + }); + + // Convert the bytes we read into a string, and then send that + // string to all other connected clients. + let line = line.map(|(reader, vec)| { + (reader, String::from_utf8(vec)) + }); + let connections = connections_inner.clone(); + line.map(move |(reader, message)| { + println!("{}: {:?}", addr, message); + let mut conns = connections.lock().unwrap(); + if let Ok(msg) = message { + // For each open connection except the sender, send the + // string via the channel. + let iter = conns.iter_mut() + .filter(|&(&k, _)| k != addr) + .map(|(_, v)| v); + for tx in iter { + tx.unbounded_send(format!("{}: {}", addr, msg)).unwrap(); + } + } else { + let tx = conns.get_mut(&addr).unwrap(); + tx.unbounded_send("You didn't send valid UTF-8.".to_string()).unwrap(); + } + reader + }) + }); + + // Whenever we receive a string on the Receiver, we write it to + // `WriteHalf<TcpStream>`. + let socket_writer = rx.fold(writer, |writer, msg| { + let amt = io::write_all(writer, msg.into_bytes()); + let amt = amt.map(|(writer, _)| writer); + amt.map_err(|_| ()) + }); + + let pool = CpuPool::new(1); + + // Now that we've got futures representing each half of the socket, we + // use the `select` combinator to wait for either half to be done to + // tear down the other. Then we spawn off the result. + let connections = connections.clone(); + let socket_reader = socket_reader.map_err(|_| ()); + let connection = socket_reader.map(|_| ()).select(socket_writer.map(|_| ())); + pool.execute(connection.then(move |_| { + connections.lock().unwrap().remove(&addr); + println!("Connection {} closed.", addr); + Ok(()) + })).unwrap(); + + Ok(()) + }); + + // execute server + future::blocking(srv).wait().unwrap(); +} |