Add a chat example (#112)

examples/hello_world.rs

@@ -0,0 +1,80 @@
+//! Hello world server.
+//!
+//! A simple server that accepts connections, writes "hello world\n", and closes
+//! the connection.
+//!
+//! You can test this out by running:
+//!
+//!     cargo run --example hello_world
+//!
+//! And then in another terminal run:
+//!
+//!     telnet localhost 6142
+//!
+
+#![deny(warnings)]
+
+extern crate tokio;
+extern crate tokio_io;
+extern crate futures;
+
+use tokio::net::TcpListener;
+use tokio_io::io;
+use futures::{current_thread, Future, Stream};
+
+pub fn main() {
+    let addr = "127.0.0.1:6142".parse().unwrap();
+
+    // Bind a TCP listener to the socket address.
+    //
+    // Note that this is the Tokio TcpListener, which is fully async.
+    let listener = TcpListener::bind(&addr).unwrap();
+
+    // The server task asynchronously iterates over and processes each
+    // incoming connection.
+    let server = listener.incoming().for_each(|socket| {
+        println!("accepted socket; addr={:?}", socket.peer_addr().unwrap());
+
+        let connection = io::write_all(socket, "hello world\n")
+            .then(|res| {
+                println!("wrote message; success={:?}", res.is_ok());
+                Ok(())
+            });
+
+        // Spawn a new task that processes the socket:
+        current_thread::spawn(connection);
+
+        Ok(())
+    })
+    .map_err(|err| {
+        // All tasks must have an `Error` type of `()`. This forces error
+        // handling and helps avoid silencing failures.
+        //
+        // In our example, we are only going to log the error to STDOUT.
+        println!("accept error = {:?}", err);
+    });
+
+    // This starts the `current_thread` executor.
+    //
+    // Executors are responsible for scheduling many asynchronous tasks, driving
+    // them to completion. There are a number of different executor
+    // implementations, each providing different scheduling characteristics.
+    //
+    // The `current_thread` executor multiplexes all scheduled tasks on the
+    // current thread. This means that spawned tasks must not implement `Send`.
+    current_thread::run(|_| {
+        // Now, the server task must be spawned.
+        //
+        // It's important to note that all futures / tasks are lazy. No work
+        // will happen unless they are spawned onto an executor.
+        current_thread::spawn(server);
+
+        println!("server running on localhost:6142");
+
+        // The `current_thread::run` function will now block until *all* spawned
+        // tasks complete.
+        //
+        // In our example, we have not defined a shutdown strategy, so
+        // this will block until `ctrl-c` is pressed at the terminal.
+    });
+}