update all websocket examples to v4

websockets/echo/src/main.rs

@@ -0,0 +1,42 @@
+//! Simple echo websocket server.
+//!
+//! Open `http://localhost:8080/` in browser to test.
+
+use actix_files::NamedFile;
+use actix_web::{
+    middleware, web, App, Error, HttpRequest, HttpResponse, HttpServer, Responder,
+};
+use actix_web_actors::ws;
+
+mod server;
+use self::server::MyWebSocket;
+
+async fn index() -> impl Responder {
+    NamedFile::open_async("./static/index.html").await.unwrap()
+}
+
+/// WebSocket handshake and start `MyWebSocket` actor.
+async fn echo_ws(req: HttpRequest, stream: web::Payload) -> Result<HttpResponse, Error> {
+    ws::start(MyWebSocket::new(), &req, stream)
+}
+
+#[actix_web::main]
+async fn main() -> std::io::Result<()> {
+    env_logger::init_from_env(env_logger::Env::new().default_filter_or("info"));
+
+    log::info!("starting HTTP server at http://localhost:8080");
+
+    HttpServer::new(|| {
+        App::new()
+            // WebSocket UI HTML file
+            .service(web::resource("/").to(index))
+            // websocket route
+            .service(web::resource("/ws").route(web::get().to(echo_ws)))
+            // enable logger
+            .wrap(middleware::Logger::default())
+    })
+    .workers(2)
+    .bind(("127.0.0.1", 8080))?
+    .run()
+    .await
+}