tokio-tls: fix examples build and run (#1963)

tokio-tls/examples/echo.rs

@@ -0,0 +1,55 @@
+#![warn(rust_2018_idioms)]
+
+// A tiny async TLS echo server with Tokio
+use native_tls;
+use native_tls::Identity;
+use tokio;
+use tokio::io::{AsyncReadExt, AsyncWriteExt};
+use tokio::net::TcpListener;
+use tokio_tls;
+
+/**
+an example to setup a tls server.
+how to test:
+wget https://127.0.0.1:12345 --no-check-certificate
+*/
+#[tokio::main]
+async fn main() -> Result<(), Box<dyn std::error::Error>> {
+    // Bind the server's socket
+    let addr = "127.0.0.1:12345".to_string();
+    let mut tcp: TcpListener = TcpListener::bind(&addr).await?;
+
+    // Create the TLS acceptor.
+    let der = include_bytes!("identity.p12");
+    let cert = Identity::from_pkcs12(der, "mypass")?;
+    let tls_acceptor =
+        tokio_tls::TlsAcceptor::from(native_tls::TlsAcceptor::builder(cert).build()?);
+    loop {
+        // Asynchronously wait for an inbound socket.
+        let (socket, remote_addr) = tcp.accept().await?;
+        let tls_acceptor = tls_acceptor.clone();
+        println!("accept connection from {}", remote_addr);
+        tokio::spawn(async move {
+            // Accept the TLS connection.
+            let mut tls_stream = tls_acceptor.accept(socket).await.expect("accept error");
+            // In a loop, read data from the socket and write the data back.
+
+            let mut buf = [0; 1024];
+            let n = tls_stream
+                .read(&mut buf)
+                .await
+                .expect("failed to read data from socket");
+
+            if n == 0 {
+                return;
+            }
+            println!("read={}", unsafe {
+                String::from_utf8_unchecked(buf[0..n].into())
+            });
+            tls_stream
+                .write_all(&buf[0..n])
+                .await
+                .expect("failed to write data to socket");
+        });
+    }
+}