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https://github.com/tokio-rs/tokio.git
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8a7e57786a
In an effort to reach API stability, the `tokio` crate is shedding its
_public_ dependencies on crates that are either a) do not provide a
stable (1.0+) release with longevity guarantees or b) match the `tokio`
release cadence. Of course, implementing `std` traits fits the
requirements.
The on exception, for now, is the `Stream` trait found in `futures_core`.
It is expected that this trait will not change much and be moved into `std.
Since Tokio is not yet going reaching 1.0, I feel that it is acceptable to maintain
a dependency on this trait given how foundational it is.
Since the `Stream` implementation is optional, types that are logically
streams provide `async fn next_*` functions to obtain the next value.
Avoiding the `next()` name prevents fn conflicts with `StreamExt::next()`.
Additionally, some misc cleanup is also done:
- `tokio::io::io` -> `tokio::io::util`.
- `delay` -> `delay_until`.
- `Timeout::new` -> `timeout(...)`.
- `signal::ctrl_c()` returns a future instead of a stream.
- `{tcp,unix}::Incoming` is removed (due to lack of `Stream` trait).
- `time::Throttle` is removed (due to lack of `Stream` trait).
- Fix: `mpsc::UnboundedSender::send(&self)` (no more conflict with `Sink` fns).
78 lines
2.4 KiB
Rust
78 lines
2.4 KiB
Rust
//! This example leverages `BytesCodec` to create a UDP client and server which
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//! speak a custom protocol.
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//!
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//! Here we're using the codec from `tokio-codec` to convert a UDP socket to a stream of
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//! client messages. These messages are then processed and returned back as a
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//! new message with a new destination. Overall, we then use this to construct a
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//! "ping pong" pair where two sockets are sending messages back and forth.
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#![warn(rust_2018_idioms)]
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use tokio::net::UdpSocket;
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use tokio::{io, time};
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use tokio_util::codec::BytesCodec;
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use tokio_util::udp::UdpFramed;
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use bytes::Bytes;
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use futures::{FutureExt, SinkExt, StreamExt};
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use std::env;
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use std::error::Error;
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use std::net::SocketAddr;
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use std::time::Duration;
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#[tokio::main]
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async fn main() -> Result<(), Box<dyn Error>> {
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let addr = env::args().nth(1).unwrap_or("127.0.0.1:0".to_string());
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// Bind both our sockets and then figure out what ports we got.
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let a = UdpSocket::bind(&addr).await?;
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let b = UdpSocket::bind(&addr).await?;
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let b_addr = b.local_addr()?;
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let mut a = UdpFramed::new(a, BytesCodec::new());
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let mut b = UdpFramed::new(b, BytesCodec::new());
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// Start off by sending a ping from a to b, afterwards we just print out
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// what they send us and continually send pings
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let a = ping(&mut a, b_addr);
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// The second client we have will receive the pings from `a` and then send
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// back pongs.
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let b = pong(&mut b);
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// Run both futures simultaneously of `a` and `b` sending messages back and forth.
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match futures::future::try_join(a, b).await {
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Err(e) => println!("an error occured; error = {:?}", e),
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_ => println!("done!"),
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}
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Ok(())
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}
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async fn ping(socket: &mut UdpFramed<BytesCodec>, b_addr: SocketAddr) -> Result<(), io::Error> {
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socket.send((Bytes::from(&b"PING"[..]), b_addr)).await?;
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for _ in 0..4usize {
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let (bytes, addr) = socket.next().map(|e| e.unwrap()).await?;
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println!("[a] recv: {}", String::from_utf8_lossy(&bytes));
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socket.send((Bytes::from(&b"PING"[..]), addr)).await?;
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}
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Ok(())
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}
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async fn pong(socket: &mut UdpFramed<BytesCodec>) -> Result<(), io::Error> {
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let timeout = Duration::from_millis(200);
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while let Ok(Some(Ok((bytes, addr)))) = time::timeout(timeout, socket.next()).await {
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println!("[b] recv: {}", String::from_utf8_lossy(&bytes));
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socket.send((Bytes::from(&b"PONG"[..]), addr)).await?;
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}
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Ok(())
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}
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