How to create a Websocket Actor in Actix

#rust, #actix, #actor-model, #websocket

To handle WebSocket in [Actix Framework] you need to create a WebSocket Actor. Each actor will be responsible for each connected client.

#[derive(Default)]
struct WsSession;

A WebSocket actor have a WebsocketContext and need to implement StreamHandler trait.

impl Actor for WsSession {
    type Context = ws::WebsocketContext<Self>;
}

type WebsocketMessage = Result<ws::Message, ws::ProtocolError>;

impl StreamHandler<WebsocketMessage> for WsSession {
    fn handle(&mut self, msg: WebsocketMessage, ctx: &mut Self::Context) {
        ...
  }
}

WebsocketContext is an Actix Context that has some special features such as handling text or binary messages, handling ping and pong messages.

The handle method of StreamHandler trait is where we process the incoming messages from the client. A ws::Message (not to be mistaken with Actor's messages) could be anything in Text or Binary or Ping/Pong.