Add optional support for TLS via async-native-tls instead of async-tls (rustls)

Can be enabled with the "native-tls" feature instead of just "tls".

Cargo.toml

@@ -14,8 +14,10 @@ edition = "2018"
 [features]
 default = ["connect", "tls", "async_std_runtime"]
 connect = ["stream"]
-async_std_runtime = ["connect", "tls", "async-std"]
-tls = ["async-tls", "stream"]
+async_std_runtime = ["connect", "async-std"]
+tls-base = ["stream"]
+tls = ["async-tls", "tls-base"]
+native-tls = ["async-native-tls", "real-native-tls", "tls-base", "tungstenite/tls"]
 stream = []
 
 [dependencies]
@@ -35,6 +37,15 @@ version = "1.0"
 optional = true
 version = "0.6.0"
 
+[dependencies.async-native-tls]
+optional = true
+version = "0.1.0"
+
+[dependencies.real-native-tls]
+optional = true
+version = "0.2"
+package = "native-tls"
+
 [dev-dependencies]
 url = "2.0.0"
 env_logger = "0.7"

src/connect.rs

@@ -7,11 +7,18 @@ use futures::io::{AsyncRead, AsyncWrite};
 
 use super::{client_async, Request, WebSocketStream};
 
-#[cfg(feature = "tls")]
+#[cfg(feature = "tls-base")]
 pub(crate) mod encryption {
+    #[cfg(feature = "tls")]
     use async_tls::client::TlsStream;
+    #[cfg(feature = "tls")]
     use async_tls::TlsConnector as AsyncTlsConnector;
 
+    #[cfg(feature = "native-tls")]
+    use async_native_tls::TlsConnector as AsyncTlsConnector;
+    #[cfg(feature = "native-tls")]
+    use async_native_tls::TlsStream;
+
     use tungstenite::stream::Mode;
     use tungstenite::Error;
 
@@ -35,21 +42,28 @@ pub(crate) mod encryption {
         match mode {
             Mode::Plain => Ok(StreamSwitcher::Plain(socket)),
             Mode::Tls => {
-                let stream = AsyncTlsConnector::new();
-                let connected = stream.connect(&domain, socket)?.await;
-                match connected {
-                    Err(e) => Err(Error::Io(e)),
-                    Ok(s) => Ok(StreamSwitcher::Tls(s)),
-                }
+                #[cfg(feature = "tls")]
+                let stream = {
+                    let connector = AsyncTlsConnector::new();
+                    connector.connect(&domain, socket)?.await?
+                };
+                #[cfg(feature = "native-tls")]
+                let stream = {
+                    let builder = real_native_tls::TlsConnector::builder();
+                    let connector = builder.build()?;
+                    let connector = AsyncTlsConnector::from(connector);
+                    connector.connect(&domain, socket).await?
+                };
+                Ok(StreamSwitcher::Tls(stream))
             }
         }
     }
 }
 
-#[cfg(feature = "tls")]
+#[cfg(feature = "tls-base")]
 pub use self::encryption::MaybeTlsStream;
 
-#[cfg(not(feature = "tls"))]
+#[cfg(not(feature = "tls-base"))]
 pub(crate) mod encryption {
     use futures::io::{AsyncRead, AsyncWrite};
     use futures::{future, Future};

src/lib.rs

@@ -49,7 +49,7 @@ pub use connect::client_async_tls;
 #[cfg(feature = "async_std_runtime")]
 pub use connect::connect_async;
 
-#[cfg(all(feature = "connect", feature = "tls"))]
+#[cfg(all(feature = "connect", feature = "tls-base"))]
 pub use connect::MaybeTlsStream;
 use std::error::Error;
 use tungstenite::protocol::CloseFrame;