flexible/java-11/websocket-jetty/src/main/java/com/example/flexible/websocket/jettynative/SendServlet.java [36:141]: - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - @WebServlet("/send") /** Servlet that sends the message sent over POST to over a websocket connection. */ public class SendServlet extends HttpServlet { private Logger logger = Logger.getLogger(SendServlet.class.getName()); private static final String ENDPOINT = "/echo"; private static final String WEBSOCKET_PROTOCOL_PREFIX = "ws://"; private static final String WEBSOCKET_HTTPS_PROTOCOL_PREFIX = "wss://"; private static final String APPENGINE_HOST_SUFFIX = ".appspot.com"; // GAE_INSTANCE environment is used to detect App Engine Flexible Environment private static final String GAE_INSTANCE_VAR = "GAE_INSTANCE"; // GOOGLE_CLOUD_PROJECT environment variable is set to the GCP project ID on App Engine Flexible. private static final String GOOGLE_CLOUD_PROJECT_ENV_VAR = "GOOGLE_CLOUD_PROJECT"; // GAE_SERVICE environment variable is set to the GCP service name. private static final String GAE_SERVICE_ENV_VAR = "GAE_SERVICE"; private final HttpClient httpClient; private final WebSocketClient webSocketClient; private final ClientSocket clientSocket; public SendServlet() { this.httpClient = createHttpClient(); this.webSocketClient = createWebSocketClient(); this.clientSocket = new ClientSocket(); } @Override public void doPost(HttpServletRequest request, HttpServletResponse response) throws IOException { String message = request.getParameter("message"); try { sendMessageOverWebSocket(message); response.sendRedirect("/"); } catch (Exception e) { logger.severe("Error sending message over socket: " + e.getMessage()); e.printStackTrace(response.getWriter()); response.setStatus(HttpStatus.INTERNAL_SERVER_ERROR_500); } } private HttpClient createHttpClient() { HttpClient httpClient; if (System.getenv(GAE_INSTANCE_VAR) != null) { // If on HTTPS, create client with SSL Context SslContextFactory.Client sslContextFactory = new SslContextFactory.Client(); httpClient = new HttpClient(sslContextFactory); } else { // local testing on HTTP httpClient = new HttpClient(); } return httpClient; } private WebSocketClient createWebSocketClient() { return new WebSocketClient(this.httpClient); } private void sendMessageOverWebSocket(String message) throws Exception { if (!httpClient.isRunning()) { try { httpClient.start(); } catch (URISyntaxException e) { e.printStackTrace(); } } if (!webSocketClient.isRunning()) { try { webSocketClient.start(); } catch (URISyntaxException e) { e.printStackTrace(); } } ClientUpgradeRequest request = new ClientUpgradeRequest(); // Attempt connection Future future = webSocketClient.connect(clientSocket, new URI(getWebSocketAddress()), request); // Wait for Connect Session session = future.get(); // Send a message session.getRemote().sendString(message); // Close session session.close(); } /** * Returns the host:port/echo address a client needs to use to communicate with the server. On App * engine Flex environments, result will be in the form wss://project-id.appspot.com/echo */ public static String getWebSocketAddress() { // Use ws://127.0.0.1:8080/echo when testing locally String webSocketHost = "127.0.0.1:8080"; String webSocketProtocolPrefix = WEBSOCKET_PROTOCOL_PREFIX; // On App Engine flexible environment, use wss://project-id.appspot.com/echo if (System.getenv(GAE_INSTANCE_VAR) != null) { String projectId = System.getenv(GOOGLE_CLOUD_PROJECT_ENV_VAR); if (projectId != null) { String serviceName = System.getenv(GAE_SERVICE_ENV_VAR); webSocketHost = serviceName + "-dot-" + projectId + APPENGINE_HOST_SUFFIX; } Preconditions.checkNotNull(webSocketHost); // Use wss:// instead of ws:// protocol when connecting over https webSocketProtocolPrefix = WEBSOCKET_HTTPS_PROTOCOL_PREFIX; } return webSocketProtocolPrefix + webSocketHost + ENDPOINT; - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - flexible/java-17/websocket-jetty/src/main/java/com/example/flexible/websocket/jettynative/SendServlet.java [36:141]: - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - @WebServlet("/send") /** Servlet that sends the message sent over POST to over a websocket connection. */ public class SendServlet extends HttpServlet { private Logger logger = Logger.getLogger(SendServlet.class.getName()); private static final String ENDPOINT = "/echo"; private static final String WEBSOCKET_PROTOCOL_PREFIX = "ws://"; private static final String WEBSOCKET_HTTPS_PROTOCOL_PREFIX = "wss://"; private static final String APPENGINE_HOST_SUFFIX = ".appspot.com"; // GAE_INSTANCE environment is used to detect App Engine Flexible Environment private static final String GAE_INSTANCE_VAR = "GAE_INSTANCE"; // GOOGLE_CLOUD_PROJECT environment variable is set to the GCP project ID on App Engine Flexible. private static final String GOOGLE_CLOUD_PROJECT_ENV_VAR = "GOOGLE_CLOUD_PROJECT"; // GAE_SERVICE environment variable is set to the GCP service name. private static final String GAE_SERVICE_ENV_VAR = "GAE_SERVICE"; private final HttpClient httpClient; private final WebSocketClient webSocketClient; private final ClientSocket clientSocket; public SendServlet() { this.httpClient = createHttpClient(); this.webSocketClient = createWebSocketClient(); this.clientSocket = new ClientSocket(); } @Override public void doPost(HttpServletRequest request, HttpServletResponse response) throws IOException { String message = request.getParameter("message"); try { sendMessageOverWebSocket(message); response.sendRedirect("/"); } catch (Exception e) { logger.severe("Error sending message over socket: " + e.getMessage()); e.printStackTrace(response.getWriter()); response.setStatus(HttpStatus.INTERNAL_SERVER_ERROR_500); } } private HttpClient createHttpClient() { HttpClient httpClient; if (System.getenv(GAE_INSTANCE_VAR) != null) { // If on HTTPS, create client with SSL Context SslContextFactory.Client sslContextFactory = new SslContextFactory.Client(); httpClient = new HttpClient(sslContextFactory); } else { // local testing on HTTP httpClient = new HttpClient(); } return httpClient; } private WebSocketClient createWebSocketClient() { return new WebSocketClient(this.httpClient); } private void sendMessageOverWebSocket(String message) throws Exception { if (!httpClient.isRunning()) { try { httpClient.start(); } catch (URISyntaxException e) { e.printStackTrace(); } } if (!webSocketClient.isRunning()) { try { webSocketClient.start(); } catch (URISyntaxException e) { e.printStackTrace(); } } ClientUpgradeRequest request = new ClientUpgradeRequest(); // Attempt connection Future future = webSocketClient.connect(clientSocket, new URI(getWebSocketAddress()), request); // Wait for Connect Session session = future.get(); // Send a message session.getRemote().sendString(message); // Close session session.close(); } /** * Returns the host:port/echo address a client needs to use to communicate with the server. On App * engine Flex environments, result will be in the form wss://project-id.appspot.com/echo */ public static String getWebSocketAddress() { // Use ws://127.0.0.1:8080/echo when testing locally String webSocketHost = "127.0.0.1:8080"; String webSocketProtocolPrefix = WEBSOCKET_PROTOCOL_PREFIX; // On App Engine flexible environment, use wss://project-id.appspot.com/echo if (System.getenv(GAE_INSTANCE_VAR) != null) { String projectId = System.getenv(GOOGLE_CLOUD_PROJECT_ENV_VAR); if (projectId != null) { String serviceName = System.getenv(GAE_SERVICE_ENV_VAR); webSocketHost = serviceName + "-dot-" + projectId + APPENGINE_HOST_SUFFIX; } Preconditions.checkNotNull(webSocketHost); // Use wss:// instead of ws:// protocol when connecting over https webSocketProtocolPrefix = WEBSOCKET_HTTPS_PROTOCOL_PREFIX; } return webSocketProtocolPrefix + webSocketHost + ENDPOINT; - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -