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116 lines
4.4 KiB
116 lines
4.4 KiB
//! A simple example of hooking up stdin/stdout to a WebSocket stream.
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//!
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//! This example will connect to a server specified in the argument list and
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//! then forward all data read on stdin to the server, printing out all data
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//! received on stdout.
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//!
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//! Note that this is not currently optimized for performance, especially around
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//! buffer management. Rather it's intended to show an example of working with a
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//! client.
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//!
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//! You can use this example together with the `server` example.
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extern crate futures;
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extern crate tokio_core;
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extern crate tokio_tungstenite;
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extern crate tungstenite;
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extern crate url;
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use std::env;
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use std::io::{self, Read, Write};
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use std::net::ToSocketAddrs;
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use std::thread;
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use futures::sync::mpsc;
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use futures::{Future, Sink, Stream};
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use tokio_core::net::TcpStream;
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use tokio_core::reactor::Core;
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use tokio_tungstenite::ClientHandshakeExt;
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use tungstenite::handshake::client::{ClientHandshake, Request};
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use tungstenite::protocol::Message;
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fn main() {
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// Specify the server address to which the client will be connecting.
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let connect_addr = env::args().nth(1).unwrap_or_else(|| {
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panic!("this program requires at least one argument")
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});
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// Get a first IP address of the server from the server URL.
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let url = url::Url::parse(&connect_addr).unwrap();
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let addr = url.to_socket_addrs().unwrap().next().unwrap();
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// Create the event loop and initiate the connection to the remote server.
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let mut core = Core::new().unwrap();
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let handle = core.handle();
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let tcp = TcpStream::connect(&addr, &handle);
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// Right now Tokio doesn't support a handle to stdin running on the event
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// loop, so we farm out that work to a separate thread. This thread will
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// read data from stdin and then send it to the event loop over a standard
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// futures channel.
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let (stdin_tx, stdin_rx) = mpsc::channel(0);
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thread::spawn(|| read_stdin(stdin_tx));
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let stdin_rx = stdin_rx.map_err(|_| panic!()); // errors not possible on rx
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// After the TCP connection has been established, we set up our client to
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// start forwarding data.
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//
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// First we do a WebSocket handshake on a TCP stream, i.e. do the upgrade
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// request.
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//
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// Half of the work we're going to do is to take all data we receive on
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// stdin (`stdin_rx`) and send that along the WebSocket stream (`sink`).
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// The second half is to take all the data we receive (`stream`) and then
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// write that to stdout. Currently we just write to stdout in a synchronous
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// fashion.
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//
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// Finally we set the client to terminate once either half of this work
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// finishes. If we don't have any more data to read or we won't receive any
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// more work from the remote then we can exit.
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let mut stdout = io::stdout();
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let client = tcp.and_then(|stream| {
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let req = Request { url: url };
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ClientHandshake::<TcpStream>::new_async(stream, req).and_then(|ws_stream| {
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println!("WebSocket handshake has been successfully completed");
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// `sink` is the stream of messages going out.
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// `stream` is the stream of incoming messages.
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let (sink, stream) = ws_stream.split();
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// We forward all messages, composed out of the data, entered to
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// the stdin, to the `sink`.
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let send_stdin = stdin_rx.forward(sink);
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let write_stdout = stream.for_each(|message| {
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stdout.write_all(&message.into_data()).unwrap();
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Ok(())
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});
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// Wait for either of futures to complete.
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send_stdin.map(|_| ())
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.select(write_stdout.map(|_| ()))
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.then(|_| Ok(()))
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}).map_err(|e| {
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println!("Error during the websocket handshake occurred: {}", e);
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io::Error::new(io::ErrorKind::Other, e)
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})
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});
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// And now that we've got our client, we execute it in the event loop!
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core.run(client).unwrap();
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}
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// Our helper method which will read data from stdin and send it along the
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// sender provided.
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fn read_stdin(mut tx: mpsc::Sender<Message>) {
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let mut stdin = io::stdin();
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loop {
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let mut buf = vec![0; 1024];
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let n = match stdin.read(&mut buf) {
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Err(_) |
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Ok(0) => break,
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Ok(n) => n,
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};
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buf.truncate(n);
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tx = tx.send(Message::binary(buf)).wait().unwrap();
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}
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}
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