async-tungstenite 0.2 gio example

Cargo.toml

[package]
name = "foo"
version = "0.1.0"
authors = ["Sebastian Dröge <sebastian@centricular.com>"]
edition = "2018"

[dependencies]
futures = "0.3"
async-tungstenite = { version = "0.2", default-features = false, features = ["stream"] }
url = "2"
glib = "0.9"
gio = "0.8"

main.rs

use async_tungstenite::{client_async, tungstenite::Message};
use futures::prelude::*;
use gio::prelude::*;
use std::io;

async fn run() -> Result<(), Box<dyn std::error::Error>> {
    let client = gio::SocketClient::new();

    client.set_tls(true);
    let connectable = gio::NetworkAddress::new("echo.websocket.org", 443);

    let socket = client
        .connect_async_future(&connectable)
        .await
        .map_err(|err| to_std_io_error(err))?;
    let socket = IOStreamAsyncReadWrite::new(socket)
        .map_err(|_| io::Error::new(io::ErrorKind::Other, "Unsupported gio::IOStream"))?;

    let url = url::Url::parse("wss://echo.websocket.org").unwrap();

    let (mut ws_stream, _) = client_async(url, socket).await?;

    let text = "Hello, World!";

    println!("Sending: \"{}\"", text);
    ws_stream.send(Message::text(text)).await?;

    let msg = ws_stream
        .next()
        .await
        .ok_or_else(|| "didn't receive anything")??;

    println!("Received: {:?}", msg);

    Ok(())
}

fn main() -> Result<(), Box<dyn std::error::Error>> {
    // Get the default main context and run our async function on it
    let main_context = glib::MainContext::default();
    main_context.block_on(run())
}

use futures::io::{AsyncRead, AsyncWrite};
use std::pin::Pin;
use std::task::{Context, Poll};

#[derive(Debug)]
struct IOStreamAsyncReadWrite<T: IsA<gio::IOStream>> {
    io_stream: T,
    read: gio::InputStreamAsyncRead<gio::PollableInputStream>,
    write: gio::OutputStreamAsyncWrite<gio::PollableOutputStream>,
}

impl<T: IsA<gio::IOStream>> IOStreamAsyncReadWrite<T> {
    fn new(stream: T) -> Result<IOStreamAsyncReadWrite<T>, T> {
        let write = stream
            .get_output_stream()
            .and_then(|s| s.dynamic_cast::<gio::PollableOutputStream>().ok())
            .and_then(|s| s.into_async_write().ok());

        let read = stream
            .get_input_stream()
            .and_then(|s| s.dynamic_cast::<gio::PollableInputStream>().ok())
            .and_then(|s| s.into_async_read().ok());

        let (read, write) = match (read, write) {
            (Some(read), Some(write)) => (read, write),
            _ => return Err(stream),
        };

        Ok(IOStreamAsyncReadWrite {
            io_stream: stream,
            read,
            write,
        })
    }
}

impl<T: IsA<gio::IOStream> + Unpin> AsyncRead for IOStreamAsyncReadWrite<T> {
    fn poll_read(
        self: Pin<&mut Self>,
        cx: &mut Context<'_>,
        buf: &mut [u8],
    ) -> Poll<Result<usize, io::Error>> {
        Pin::new(&mut Pin::get_mut(self).read).poll_read(cx, buf)
    }
}

impl<T: IsA<gio::IOStream> + Unpin> AsyncWrite for IOStreamAsyncReadWrite<T> {
    fn poll_write(
        self: Pin<&mut Self>,
        cx: &mut Context<'_>,
        buf: &[u8],
    ) -> Poll<Result<usize, io::Error>> {
        Pin::new(&mut Pin::get_mut(self).write).poll_write(cx, buf)
    }

    fn poll_close(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Result<(), io::Error>> {
        Pin::new(&mut Pin::get_mut(self).write).poll_close(cx)
    }

    fn poll_flush(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Result<(), io::Error>> {
        Pin::new(&mut Pin::get_mut(self).write).poll_flush(cx)
    }
}

unsafe impl<T: IsA<gio::IOStream>> Send for IOStreamAsyncReadWrite<T> {}
unsafe impl<T: IsA<gio::IOStream>> Sync for IOStreamAsyncReadWrite<T> {}

fn to_std_io_error(error: glib::Error) -> io::Error {
    match error.kind::<gio::IOErrorEnum>() {
        Some(io_error_enum) => io::Error::new(io_error_enum.into(), error),
        None => io::Error::new(io::ErrorKind::Other, error),
    }
}