Add tutorial for intercepting web sockets

settings.gradle.kts

@@ -49,3 +49,4 @@ module("crx-extensions", "./tutorials/crx-extensions")
 // Automation with MCP
 module("mcp-devtools", "./tutorials/ai/mcp-devtools")
 module("mcp-extension", "./tutorials/ai/mcp-extension")
+module("intercepting-web-sockets", "./tutorials/intercepting-web-sockets")

tutorials/intercepting-web-sockets/src/main/java/WebSocketInterceptor.java

@@ -0,0 +1,98 @@
+/*
+ *  Copyright 2026, TeamDev. All rights reserved.
+ *
+ *  Redistribution and use in source and/or binary forms, with or without
+ *  modification, must retain the above copyright notice and the following
+ *  disclaimer.
+ *
+ *  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ *  "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ *  LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ *  A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ *  OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ *  SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ *  LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ *  DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ *  THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ *  (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ *  OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+import com.teamdev.jxbrowser.browser.callback.InjectJsCallback;
+import com.teamdev.jxbrowser.engine.Engine;
+import com.teamdev.jxbrowser.engine.RenderingMode;
+import com.teamdev.jxbrowser.frame.Frame;
+import com.teamdev.jxbrowser.js.JsFunctionCallback;
+import com.teamdev.jxbrowser.js.JsObject;
+import com.teamdev.jxbrowser.view.swing.BrowserView;
+import java.awt.BorderLayout;
+import java.io.IOException;
+import java.nio.charset.StandardCharsets;
+import javax.swing.JFrame;
+import javax.swing.SwingUtilities;
+import javax.swing.WindowConstants;
+
+public class WebSocketInterceptor {
+
+    public static void main(String[] args) {
+        var engine = Engine.newInstance(RenderingMode.HARDWARE_ACCELERATED);
+        var browser = engine.newBrowser();
+
+        // Inject JavaScript and register bridge functions.
+        browser.set(InjectJsCallback.class, params -> {
+            var frame = params.frame();
+            injectInterceptor(frame);
+            registerBridgeFunctions(frame);
+            return InjectJsCallback.Response.proceed();
+        });
+
+        SwingUtilities.invokeLater(() -> {
+            var view = BrowserView.newInstance(browser);
+
+            var frame = new JFrame("WebSocket Interceptor");
+            frame.setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);
+            frame.add(view, BorderLayout.CENTER);
+            frame.setSize(800, 600);
+            frame.setVisible(true);
+        });
+
+        // Load the demo HTML page.
+        var html = loadResource("websocket-demo.html");
+        browser.navigation().loadHtml(html);
+    }
+
+    private static void injectInterceptor(Frame frame) {
+        var script = loadResource("websocket-interceptor.js");
+        frame.executeJavaScript(script);
+    }
+
+    private static void registerBridgeFunctions(Frame frame) {
+        JsObject window = frame.executeJavaScript("window");
+
+        window.putProperty("onWebSocketReceived", (JsFunctionCallback) args -> {
+            var data = (byte[]) args[0];
+            System.out.println("[RECEIVED] " + data);
+            return null;
+        });
+
+        window.putProperty("onWebSocketSent", (JsFunctionCallback) args -> {
+            var data = args[0].toString();
+            System.out.println("[SENT] " + data);
+            return null;
+        });
+    }
+
+    private static String loadResource(String resourceName) {
+        try (var stream = WebSocketInterceptor.class.getResourceAsStream(
+                "/" + resourceName)) {
+            if (stream == null) {
+                throw new RuntimeException(
+                        "Resource not found: " + resourceName);
+            }
+            return new String(stream.readAllBytes(), StandardCharsets.UTF_8);
+        } catch (IOException e) {
+            throw new RuntimeException(
+                    "Failed to load resource: " + resourceName, e);
+        }
+    }
+}

tutorials/intercepting-web-sockets/src/main/resources/websocket-demo.html

@@ -0,0 +1,43 @@
+<!DOCTYPE html>
+<html>
+<head>
+    <title>WebSocket Interception Demo</title>
+</head>
+<body>
+    <h1>WebSocket Interception Demo</h1>
+    <button id="connect">Connect</button>
+    <button id="send" disabled>Send Message</button>
+    <button id="disconnect" disabled>Disconnect</button>
+    <div id="status">Not connected</div>
+
+    <script>
+        let socket = null;
+
+        document.getElementById('connect').addEventListener('click', () => {
+            socket = new WebSocket('wss://echo.websocket.org/');
+
+            socket.addEventListener('open', () => {
+                document.getElementById('status').textContent = 'Connected';
+                document.getElementById('connect').disabled = true;
+                document.getElementById('send').disabled = false;
+                document.getElementById('disconnect').disabled = false;
+            });
+
+            socket.addEventListener('close', () => {
+                document.getElementById('status').textContent = 'Disconnected';
+                document.getElementById('connect').disabled = false;
+                document.getElementById('send').disabled = true;
+                document.getElementById('disconnect').disabled = true;
+            });
+        });
+
+        document.getElementById('send').addEventListener('click', () => {
+            socket.send('Hello from browser at ' + new Date().toISOString());
+        });
+
+        document.getElementById('disconnect').addEventListener('click', () => {
+            socket.close();
+        });
+    </script>
+</body>
+</html>

tutorials/intercepting-web-sockets/src/main/resources/websocket-interceptor.js

@@ -0,0 +1,28 @@
+// Save reference to the native WebSocket.
+const NativeWebSocket = window.WebSocket;
+
+// Override the global WebSocket constructor.
+window.WebSocket = function(url, protocols) {
+    const socket = new NativeWebSocket(url, protocols);
+
+    // Intercept incoming messages.
+    socket.addEventListener('message', (event) => {
+        if (window.onWebSocketReceived) {
+            window.onWebSocketReceived(event.data);
+        }
+    });
+
+    // Intercept outgoing messages.
+    const originalSend = socket.send;
+    socket.send = function(data) {
+        if (window.onWebSocketSent) {
+            window.onWebSocketSent(data);
+        }
+        originalSend.call(socket, data);
+    };
+
+    return socket;
+};
+
+// Preserve the prototype chain.
+window.WebSocket.prototype = NativeWebSocket.prototype;