Force-close clients on IO error (#110)

CHANGELOG.md

@@ -7,6 +7,7 @@ and this project adheres to [Semantic Versioning](http://semver.org/).
 ## v0.6.3
 
 - Allow users to use tokio v2.4.0 in their projects. See [#106](https://github.com/gbaranski/ezsockets/pull/106).
+- Force-close clients if they encounter an IO error, since an IO error might mean the client is hanging (e.g. after an IP address change) and should be reconstructed.
 - Return `CloseCode::Abnormal` from keepalive timeouts instead of `CloseCode::Normal`.
 - Fix DDOS by honest clients when servers check capacity *after* clients connect.
 

src/client.rs

@@ -526,20 +526,24 @@ impl<E: ClientExt, C: ClientConnector> ClientActor<E, C> {
                 );
             }
             match result {
-                Err(WSError::ConnectionClosed)
-                | Err(WSError::AlreadyClosed)
-                | Err(WSError::Io(_))
-                | Err(WSError::Tls(_)) => {
+                Err(WSError::ConnectionClosed) | Err(WSError::AlreadyClosed) => {
                     // either:
                     // A) The connection was closed via the close protocol, so we will allow the stream to
                     //    handle it.
                     // B) We already tried and failed to submit another message, so now we are
                     //    waiting for other parts of the select! to shut us down.
-                    // C) An IO error means the connection closed unexpectedly, so we can try to reconnect when
-                    //    the stream fails.
+                }
+                Err(WSError::Io(_)) | Err(WSError::Tls(_)) => {
+                    // An IO error means the connection closed unexpectedly. We don't know if the stream is
+                    // hanging or if it will shut down, so we force-close the socket.
+                    //
+                    // There are edge cases where this erroneously closes the connection even though we'd rather
+                    // use auto-reconnect. TODO: isolate the error cases where force-closing is appropriate.
+                    return Err(Error::from("encountered IO sink close error, force-closing client actor since connection \
+                        might be hanging"));
                 }
                 Err(_) if !closed_self => {
-                    return Err(Error::from("unexpected sink error, aborting client actor"))
+                    return Err(Error::from("unexpected sink error, aborting client actor"));
                 }
                 _ => (),
             }