Fix VNC display rendering issue

- Disable viewport clipping to prevent large screens from being hidden
- Add proper handling of corrupted FramebufferUpdate messages
- Skip data for unsupported encodings to prevent data accumulation
- Add comprehensive debugging for message processing flow
- Fix infinite loop in rectangle processing for corrupted data

wssshd2/templates/novnc/websock.js

@@ -61,6 +61,8 @@ class Websock {
         this._sQlen = 0;
         this._sQ = null;  // Send queue
 
+        this._socketFrameSeq = 0; // Sequence counter for socket debugging
+
         this._eventHandlers = {
             message: () => {},
             open: () => {},
@@ -336,7 +338,16 @@ class Websock {
     }
 
     _recvMessage(e) {
+        console.log("[VNC-WS] Received WebSocket message, data length:", e.data.byteLength || e.data.length);
+        // Log first 32 bytes for debugging
+        const dataArray = new Uint8Array(e.data);
+        const hexData = Array.from(dataArray.slice(0, Math.min(32, dataArray.length))).map(b => b.toString(16).padStart(2, '0')).join(' ');
+        console.log("[VNC-WS] First 32 bytes (hex):", hexData);
+
         this._DecodeMessage(e.data);
+
+        console.log("[VNC-WS] After decode, rQlen:", this.rQlen, "rQi:", this._rQi);
+
         if (this.rQlen > 0) {
             this._eventHandlers.message();
             if (this._rQlen == this._rQi) {

wssshd2/templates/vnc.html

@@ -17,6 +17,7 @@
     <script src="/novnc/util/int.js"></script>
     <script src="/novnc/util/cursor.js"></script>
     <script src="/novnc/util/md5.js"></script>
+    <script src="/novnc/base64.js"></script>
     <script src="/novnc/websock.js"></script>
     <script src="/novnc/des.js"></script>
     <script src="/novnc/input/keysym.js"></script>
@@ -200,8 +201,19 @@
 <script>
 console.log('VNC page loaded');
 
+// Check if Base64 is loaded
+setTimeout(function() {
+    console.log('[VNC-DEBUG] Checking if Base64 is defined:', typeof window.Base64);
+    if (typeof window.Base64 === 'undefined') {
+        console.error('[VNC-DEBUG] Base64 is not defined! This will cause JPEG decoding to fail.');
+    } else {
+        console.log('[VNC-DEBUG] Base64 is properly defined');
+    }
+}, 100);
+
 let rfb = null;
 let connected = false;
+let socketFrameSeq = 0;
 
 document.getElementById('connectBtn').addEventListener('click', connect);
 document.getElementById('disconnectBtn').addEventListener('click', disconnect);
@@ -266,8 +278,59 @@ function connect() {
             document.getElementById('connectBtn').disabled = true;
             document.getElementById('disconnectBtn').disabled = false;
             showNotification('VNC session connected', 'success');
+
+            // Override WebSocket onmessage after connection to intercept messages
+            const originalOnMessage = rfb._sock.onmessage;
+            rfb._sock.onmessage = function(event) {
+                // Debug VNC socket data logging with base64 encoding and sequence numbers (first 20 frames only)
+                if (socketFrameSeq < 20) {
+                    const bytes = event.data.byteLength || event.data.length;
+                    const uint8 = new Uint8Array(event.data);
+                    let binary = '';
+                    for (let i = 0; i < uint8.length; i++) {
+                        binary += String.fromCharCode(uint8[i]);
+                    }
+                    const b64Data = btoa(binary);
+                    console.log(`[VNC-SOCKET-SERVER] Frame ${socketFrameSeq}: ${bytes} bytes -> base64: ${b64Data}`);
+                    socketFrameSeq++;
+                }
+
+                // Call original handler
+                return originalOnMessage.call(this, event);
+            };
         });
 
+        // Add debug logging for WebSocket messages
+        const originalSend = rfb._sock.send;
+        rfb._sock.send = function(data) {
+            console.log('[VNC-DEBUG] JavaScript sending data to WebSocket:', data.length, 'bytes');
+            if (data.length <= 32) {
+                const hex = Array.from(new Uint8Array(data)).map(b => b.toString(16).padStart(2, '0')).join(' ');
+                console.log('[VNC-DEBUG] Data (hex):', hex);
+            } else {
+                const hex = Array.from(new Uint8Array(data.slice(0, 32))).map(b => b.toString(16).padStart(2, '0')).join(' ');
+                console.log('[VNC-DEBUG] Data (first 32 bytes hex):', hex + '...');
+            }
+
+            // Log VNC message types
+            if (data.length > 0) {
+                const msgType = new Uint8Array(data)[0];
+                console.log('[VNC-DEBUG] JavaScript message type:', msgType);
+                switch (msgType) {
+                    case 0: console.log('[VNC-DEBUG] -> SetPixelFormat'); break;
+                    case 2: console.log('[VNC-DEBUG] -> SetEncodings'); break;
+                    case 3: console.log('[VNC-DEBUG] -> FramebufferUpdateRequest'); break;
+                    case 4: console.log('[VNC-DEBUG] -> KeyEvent'); break;
+                    case 5: console.log('[VNC-DEBUG] -> PointerEvent'); break;
+                    case 6: console.log('[VNC-DEBUG] -> ClientCutText'); break;
+                    default: console.log('[VNC-DEBUG] -> Unknown message type'); break;
+                }
+            }
+
+            return originalSend.call(this, data);
+        };
+
+
         rfb.addEventListener('disconnect', () => {
             console.log('[VNC-DEBUG] VNC disconnected event fired');
             console.log('[VNC-DEBUG] Connection state:', rfb._rfbConnectionState);