From d5fd035956096d6eb4404fc27a84ccade347d74c Mon Sep 17 00:00:00 2001
From: Florian Gilcher <florian.gilcher@ferrous-systems.com>
Date: Fri, 1 Nov 2019 16:10:37 +0100
Subject: [PATCH] Small example for a TCP server that both handles IP v4 and v6
 (#418)

* Add a small example for listening to both ipv4 and ipv6

Presenting stream merge on Incoming.

* Change stable checks workflow to not cover examples, but tests
---
 .github/workflows/ci.yml        |  2 +-
 examples/tcp-ipv4-and-6-echo.rs | 44 +++++++++++++++++++++++++++++++++
 2 files changed, 45 insertions(+), 1 deletion(-)
 create mode 100644 examples/tcp-ipv4-and-6-echo.rs

diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index ac49bd6..0671283 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -32,7 +32,7 @@ jobs:
       uses: actions-rs/cargo@v1
       with:
         command: check
-        args: --all --bins --examples
+        args: --all --bins --tests
 
     - name: check unstable
       uses: actions-rs/cargo@v1
diff --git a/examples/tcp-ipv4-and-6-echo.rs b/examples/tcp-ipv4-and-6-echo.rs
new file mode 100644
index 0000000..aef5e15
--- /dev/null
+++ b/examples/tcp-ipv4-and-6-echo.rs
@@ -0,0 +1,44 @@
+//! TCP echo server, accepting connections both on both ipv4 and ipv6 sockets.
+//!
+//! To send messages, do:
+//!
+//! ```sh
+//! $ nc 127.0.0.1 8080
+//! $ nc ::1 8080
+//! ```
+
+use async_std::io;
+use async_std::net::{TcpListener, TcpStream};
+use async_std::prelude::*;
+use async_std::task;
+
+async fn process(stream: TcpStream) -> io::Result<()> {
+    println!("Accepted from: {}", stream.peer_addr()?);
+
+    let (reader, writer) = &mut (&stream, &stream);
+    io::copy(reader, writer).await?;
+
+    Ok(())
+}
+
+fn main() -> io::Result<()> {
+    task::block_on(async {
+        let ipv4_listener = TcpListener::bind("127.0.0.1:8080").await?;
+        println!("Listening on {}", ipv4_listener.local_addr()?);
+        let ipv6_listener = TcpListener::bind("[::1]:8080").await?;
+        println!("Listening on {}", ipv6_listener.local_addr()?);
+
+        let ipv4_incoming = ipv4_listener.incoming();
+        let ipv6_incoming = ipv6_listener.incoming();
+
+        let mut incoming = ipv4_incoming.merge(ipv6_incoming);
+
+        while let Some(stream) = incoming.next().await {
+            let stream = stream?;
+            task::spawn(async {
+                process(stream).await.unwrap();
+            });
+        }
+        Ok(())
+    })
+}