fix: graceful shutdown of ws conn

rust/src/client_api/browser.rs

@@ -13,6 +13,13 @@ pub struct WebApi {
     error_handler: Box<dyn FnMut(Error) + 'static>,
 }
 
+impl Drop for WebApi {
+    fn drop(&mut self) {
+        // Close with normal closure code when dropped
+        let _ = self.conn.close_with_code(1000);
+    }
+}
+
 impl WebApi {
     pub fn start<ErrFn>(
         conn: Connection,

rust/src/client_api/client_events.rs

@@ -247,9 +247,15 @@ impl ContractError {
 pub enum ClientRequest<'a> {
     DelegateOp(#[serde(borrow)] DelegateRequest<'a>),
     ContractOp(#[serde(borrow)] ContractRequest<'a>),
-    Disconnect { cause: Option<Cow<'static, str>> },
-    Authenticate { token: String },
+    Disconnect {
+        cause: Option<Cow<'static, str>>,
+    },
+    Authenticate {
+        token: String,
+    },
     NodeQueries(ConnectedPeers),
+    /// Gracefully disconnect from the host.
+    Close,
 }
 
 #[derive(Serialize, Deserialize, Debug, Clone)]
@@ -297,6 +303,7 @@ impl ClientRequest<'_> {
             ClientRequest::Disconnect { cause } => ClientRequest::Disconnect { cause },
             ClientRequest::Authenticate { token } => ClientRequest::Authenticate { token },
             ClientRequest::NodeQueries(query) => ClientRequest::NodeQueries(query),
+            ClientRequest::Close => ClientRequest::Close,
         }
     }
 
@@ -600,6 +607,7 @@ impl Display for ClientRequest<'_> {
             ClientRequest::Disconnect { .. } => write!(f, "client disconnected"),
             ClientRequest::Authenticate { .. } => write!(f, "authenticate"),
             ClientRequest::NodeQueries(query) => write!(f, "node queries: {:?}", query),
+            ClientRequest::Close => write!(f, "close"),
         }
     }
 }

rust/src/client_api/regular.rs

@@ -9,7 +9,13 @@ use tokio::{
     net::TcpStream,
     sync::mpsc::{self, Receiver, Sender},
 };
-use tokio_tungstenite::{tungstenite::Message, MaybeTlsStream, WebSocketStream};
+use tokio_tungstenite::{
+    tungstenite::{
+        protocol::{frame::coding::CloseCode, CloseFrame},
+        Message,
+    },
+    MaybeTlsStream, WebSocketStream,
+};
 
 type Connection = WebSocketStream<MaybeTlsStream<TcpStream>>;
 
@@ -19,6 +25,15 @@ pub struct WebApi {
     queue: Vec<ClientRequest<'static>>,
 }
 
+impl Drop for WebApi {
+    fn drop(&mut self) {
+        let req = self.request_tx.clone();
+        tokio::spawn(async move {
+            let _ = req.send(ClientRequest::Close).await;
+        });
+    }
+}
+
 impl Stream for WebApi {
     type Item = HostResult;
 
@@ -114,6 +129,7 @@ impl WebApi {
         res.ok_or_else(|| ClientError::from(ErrorKind::ChannelClosed))?
     }
 
+    #[doc(hidden)]
     pub async fn disconnect(self, cause: impl Into<Cow<'static, str>>) {
         let _ = self
             .request_tx
@@ -148,6 +164,7 @@ async fn request_handler(
     tracing::debug!(?error, "request handler error");
     let error = match error {
         Error::ChannelClosed => ErrorKind::ChannelClosed.into(),
+        Error::ConnectionClosed => ErrorKind::Disconnect.into(),
         other => ClientError::from(format!("{other}")),
     };
     let _ = response_tx.send(Err(error)).await;
@@ -163,6 +180,17 @@ async fn process_request(
         .map_err(Into::into)
         .map_err(Error::OtherError)?;
     conn.send(Message::Binary(msg.into())).await?;
+    if let ClientRequest::Disconnect { cause } = req {
+        conn.close(cause.map(|c| CloseFrame {
+            code: CloseCode::Normal,
+            reason: format!("{c}").into(),
+        }))
+        .await?;
+        return Err(Error::ConnectionClosed);
+    } else if let ClientRequest::Close = req {
+        conn.close(None).await?;
+        return Err(Error::ConnectionClosed);
+    }
     Ok(())
 }