Implementing WebSocked Support for immediately ban-messages

2026-04-11 13:47:05 +02:00 · 2025-12-15 20:12:41 +01:00
parent 5163e4f1f4
commit 3ad4821cb7
15 changed files with 930 additions and 139 deletions
--- a/pkg/web/handlers.go
+++ b/pkg/web/handlers.go
@@ -46,6 +46,14 @@ import (
 	"github.com/swissmakers/fail2ban-ui/internal/storage"
 )

+// wsHub is the global WebSocket hub instance
+var wsHub *Hub
+
+// SetWebSocketHub sets the global WebSocket hub instance
+func SetWebSocketHub(hub *Hub) {
+	wsHub = hub
+}
+
 // SummaryResponse is what we return from /api/summary
 type SummaryResponse struct {
 	Jails []fail2ban.JailInfo `json:"jails"`
@@ -603,6 +611,11 @@ func HandleBanNotification(ctx context.Context, server config.Fail2banServer, ip
 		log.Printf("⚠️ Failed to record ban event: %v", err)
 	}

+	// Broadcast ban event to WebSocket clients
+	if wsHub != nil {
+		wsHub.BroadcastBanEvent(event)
+	}
+
 	evaluateAdvancedActions(ctx, settings, server, ip)

 	// Check if country is in alert list
--- a/pkg/web/routes.go
+++ b/pkg/web/routes.go
@@ -21,7 +21,9 @@ import (
 )

 // RegisterRoutes sets up the routes for the Fail2ban UI.
-func RegisterRoutes(r *gin.Engine) {
+func RegisterRoutes(r *gin.Engine, hub *Hub) {
+	// Set the global WebSocket hub
+	SetWebSocketHub(hub)

 	// Render the dashboard
 	r.GET("/", IndexHandler)
@@ -72,5 +74,8 @@ func RegisterRoutes(r *gin.Engine) {
 		api.GET("/events/bans", ListBanEventsHandler)
 		api.GET("/events/bans/stats", BanStatisticsHandler)
 		api.GET("/events/bans/insights", BanInsightsHandler)
+
+		// WebSocket endpoint
+		api.GET("/ws", WebSocketHandler(hub))
 	}
 }
--- a/pkg/web/static/fail2ban-ui.css
+++ b/pkg/web/static/fail2ban-ui.css
@@ -156,6 +156,148 @@ mark {
    background-color: #d97706;
 }

+.toast-ban-event {
+    background-color: #7f1d1d;
+    pointer-events: auto;
+    cursor: pointer;
+}
+
+.toast-ban-event:hover {
+    background-color: #991b1b;
+    transform: translateY(-2px);
+    box-shadow: 0 15px 20px -3px rgba(0, 0, 0, 0.15);
+}
+
+/* Backend Status Indicator */
+#backendStatus {
+    display: flex;
+    align-items: center;
+    gap: 0.5rem;
+    padding: 0.25rem 0.5rem;
+    margin-left: 5px;
+    border-radius: 0.25rem;
+    /* background-color: rgba(255, 255, 255, 0.1); */
+    transition: background-color 0.2s ease;
+}
+
+#backendStatus:hover {
+    background-color: rgba(255, 255, 255, 0.15);
+}
+
+#statusDot {
+    width: 0.5rem;
+    height: 0.5rem;
+    border-radius: 50%;
+    display: inline-block;
+    transition: background-color 0.3s ease, box-shadow 0.3s ease;
+    box-shadow: 0 0 0 0 rgba(34, 197, 94, 0.7);
+    animation: pulse 2s infinite;
+}
+
+#statusDot.bg-green-500 {
+    box-shadow: 0 0 0 0 rgba(34, 197, 94, 0.7);
+    animation: pulseGreen 2s infinite;
+}
+
+#statusDot.bg-yellow-500 {
+    box-shadow: 0 0 0 0 rgba(234, 179, 8, 0.7);
+    animation: pulseYellow 2s infinite;
+}
+
+#statusDot.bg-red-500 {
+    box-shadow: 0 0 0 0 rgba(239, 68, 68, 0.7);
+    animation: pulseRed 2s infinite;
+}
+
+#statusDot.bg-gray-400 {
+    animation: none;
+}
+
+#statusText {
+    font-size: 0.75rem;
+    font-weight: 500;
+    color: rgba(255, 255, 255, 0.9);
+    white-space: nowrap;
+}
+
+@keyframes pulseGreen {
+    0% {
+        box-shadow: 0 0 0 0 rgba(34, 197, 94, 0.7);
+    }
+    70% {
+        box-shadow: 0 0 0 4px rgba(34, 197, 94, 0);
+    }
+    100% {
+        box-shadow: 0 0 0 0 rgba(34, 197, 94, 0);
+    }
+}
+
+@keyframes pulseYellow {
+    0% {
+        box-shadow: 0 0 0 0 rgba(234, 179, 8, 0.7);
+    }
+    70% {
+        box-shadow: 0 0 0 4px rgba(234, 179, 8, 0);
+    }
+    100% {
+        box-shadow: 0 0 0 0 rgba(234, 179, 8, 0);
+    }
+}
+
+@keyframes pulseRed {
+    0% {
+        box-shadow: 0 0 0 0 rgba(239, 68, 68, 0.7);
+    }
+    70% {
+        box-shadow: 0 0 0 4px rgba(239, 68, 68, 0);
+    }
+    100% {
+        box-shadow: 0 0 0 0 rgba(239, 68, 68, 0);
+    }
+}
+
+/* Clock Display */
+#clockDisplay {
+    display: flex;
+    align-items: center;
+    padding: 0.25rem 0.75rem;
+    border-radius: 0.25rem;
+    background-color: rgba(255, 255, 255, 0.1);
+    transition: background-color 0.2s ease;
+}
+
+#clockDisplay:hover {
+    background-color: rgba(255, 255, 255, 0.15);
+}
+
+#clockTime {
+    font-family: 'Courier New', Courier, monospace;
+    font-size: 0.875rem;
+    font-weight: 600;
+    color: rgba(255, 255, 255, 0.95);
+    letter-spacing: 0.05em;
+    text-shadow: 0 1px 2px rgba(0, 0, 0, 0.1);
+}
+
+/* Mobile responsive adjustments */
+@media (max-width: 768px) {
+    #backendStatus {
+        padding: 0.125rem 0.375rem;
+    }
+    
+    #statusText {
+        font-size: 0.625rem;
+    }
+    
+    #clockDisplay {
+        padding: 0.125rem 0.5rem;
+    }
+    
+    #clockTime {
+        font-size: 0.75rem;
+    }
+}
+
 #advancedMikrotikFields, #advancedPfSenseFields {
    padding: 10px;
-}
+}
--- a/pkg/web/static/js/core.js
+++ b/pkg/web/static/js/core.js
@@ -18,6 +18,13 @@ function showLoading(show) {
 function showToast(message, type) {
  var container = document.getElementById('toast-container');
  if (!container || !message) return;
+  
+  // Handle ban event objects
+  if (typeof message === 'object' && message.type === 'ban_event') {
+    showBanEventToast(message.data || message);
+    return;
+  }
+  
  var toast = document.createElement('div');
  var variant = type || 'info';
  toast.className = 'toast toast-' + variant;
@@ -34,6 +41,60 @@ function showToast(message, type) {
  }, 5000);
 }

+// Show toast for ban event
+function showBanEventToast(event) {
+  var container = document.getElementById('toast-container');
+  if (!container || !event) return;
+  
+  var toast = document.createElement('div');
+  toast.className = 'toast toast-ban-event';
+  
+  var ip = event.ip || 'Unknown IP';
+  var jail = event.jail || 'Unknown Jail';
+  var server = event.serverName || event.serverId || 'Unknown Server';
+  var country = event.country || 'UNKNOWN';
+  
+  toast.innerHTML = ''
+    + '<div class="flex items-start gap-3">'
+    + '  <div class="flex-shrink-0 mt-1">'
+    + '    <i class="fas fa-shield-alt text-red-500"></i>'
+    + '  </div>'
+    + '  <div class="flex-1 min-w-0">'
+    + '    <div class="font-semibold text-sm">New Block Detected</div>'
+    + '    <div class="text-sm mt-1">'
+    + '      <span class="font-mono font-semibold">' + escapeHtml(ip) + '</span>'
+    + '      <span class="text-gray-500"> banned in </span>'
+    + '      <span class="font-semibold">' + escapeHtml(jail) + '</span>'
+    + '    </div>'
+    + '    <div class="text-xs text-gray-400 mt-1">'
+    + '      ' + escapeHtml(server) + ' • ' + escapeHtml(country)
+    + '    </div>'
+    + '  </div>'
+    + '</div>';
+  
+  // Add click handler to scroll to ban events table
+  toast.addEventListener('click', function() {
+    var logSection = document.getElementById('logOverviewSection');
+    if (logSection) {
+      logSection.scrollIntoView({ behavior: 'smooth', block: 'start' });
+    }
+  });
+  
+  toast.style.cursor = 'pointer';
+  container.appendChild(toast);
+  
+  requestAnimationFrame(function() {
+    toast.classList.add('show');
+  });
+  
+  setTimeout(function() {
+    toast.classList.remove('show');
+    setTimeout(function() {
+      toast.remove();
+    }, 300);
+  }, 5000);
+}
+
 // Escape HTML to prevent XSS
 function escapeHtml(value) {
  if (value === undefined || value === null) return '';
--- a/pkg/web/static/js/dashboard.js
+++ b/pkg/web/static/js/dashboard.js
@@ -74,6 +74,10 @@ function fetchBanEventsData() {
    .then(function(res) { return res.json(); })
    .then(function(data) {
      latestBanEvents = data && data.events ? data.events : [];
+      // Track the last event ID to prevent duplicates from WebSocket
+      if (latestBanEvents.length > 0 && wsManager) {
+        wsManager.lastBanEventId = latestBanEvents[0].id;
+      }
    })
    .catch(function(err) {
      console.error('Error fetching ban events:', err);
@@ -81,6 +85,72 @@ function fetchBanEventsData() {
    });
 }

+// Add new ban event from WebSocket
+function addBanEventFromWebSocket(event) {
+  // Check if event already exists (prevent duplicates)
+  // Only check by ID if both events have IDs
+  var exists = false;
+  if (event.id) {
+    exists = latestBanEvents.some(function(e) {
+      return e.id === event.id;
+    });
+  } else {
+    // If no ID, check by IP, jail, and occurredAt timestamp
+    exists = latestBanEvents.some(function(e) {
+      return e.ip === event.ip && 
+             e.jail === event.jail && 
+             e.occurredAt === event.occurredAt;
+    });
+  }
+  
+  if (!exists) {
+    console.log('Adding new ban event from WebSocket:', event);
+    
+    // Prepend to the beginning of the array
+    latestBanEvents.unshift(event);
+    // Keep only the last 200 events
+    if (latestBanEvents.length > 200) {
+      latestBanEvents = latestBanEvents.slice(0, 200);
+    }
+    
+    // Show toast notification first
+    if (typeof showBanEventToast === 'function') {
+      showBanEventToast(event);
+    }
+    
+    // Refresh dashboard data (summary, stats, insights) and re-render
+    refreshDashboardData();
+  } else {
+    console.log('Skipping duplicate ban event:', event);
+  }
+}
+
+// Refresh dashboard data when new ban event arrives via WebSocket
+function refreshDashboardData() {
+  // Refresh ban statistics and insights in the background
+  // Also refresh summary if we have a server selected
+  var enabledServers = serversCache.filter(function(s) { return s.enabled; });
+  var summaryPromise;
+  if (serversCache.length && enabledServers.length && currentServerId) {
+    summaryPromise = fetchSummaryData();
+  } else {
+    summaryPromise = Promise.resolve();
+  }
+  
+  Promise.all([
+    summaryPromise,
+    fetchBanStatisticsData(),
+    fetchBanInsightsData()
+  ]).then(function() {
+    // Re-render the dashboard to show updated stats
+    renderDashboard();
+  }).catch(function(err) {
+    console.error('Error refreshing dashboard data:', err);
+    // Still re-render even if refresh fails
+    renderDashboard();
+  });
+}
+
 function fetchBanInsightsData() {
  var sevenDaysAgo = new Date(Date.now() - (7 * 24 * 60 * 60 * 1000)).toISOString();
  var sinceQuery = '?since=' + encodeURIComponent(sevenDaysAgo);
--- a/pkg/web/static/js/header.js
+++ b/pkg/web/static/js/header.js
@@ -0,0 +1,102 @@
+// Header components: Clock and Backend Status Indicator
+"use strict";
+
+var clockInterval = null;
+var statusUpdateCallback = null;
+
+// Initialize clock
+function initClock() {
+  function updateClock() {
+    var now = new Date();
+    var hours = String(now.getHours()).padStart(2, '0');
+    var minutes = String(now.getMinutes()).padStart(2, '0');
+    var seconds = String(now.getSeconds()).padStart(2, '0');
+    var timeString = hours + ':' + minutes + ':' + seconds;
+    
+    var clockElement = document.getElementById('clockTime');
+    if (clockElement) {
+      clockElement.textContent = timeString;
+    }
+  }
+  
+  // Update immediately
+  updateClock();
+  
+  // Update every second
+  if (clockInterval) {
+    clearInterval(clockInterval);
+  }
+  clockInterval = setInterval(updateClock, 1000);
+}
+
+// Update status indicator
+function updateStatusIndicator(state, text) {
+  var statusDot = document.getElementById('statusDot');
+  var statusText = document.getElementById('statusText');
+  
+  if (!statusDot || !statusText) {
+    return;
+  }
+  
+  // Remove all color classes
+  statusDot.classList.remove('bg-green-500', 'bg-yellow-500', 'bg-red-500', 'bg-gray-400');
+  
+  // Set color and text based on state
+  switch (state) {
+    case 'connected':
+      statusDot.classList.add('bg-green-500');
+      statusText.textContent = text || 'Connected';
+      break;
+    case 'connecting':
+    case 'reconnecting':
+      statusDot.classList.add('bg-yellow-500');
+      statusText.textContent = text || 'Connecting...';
+      break;
+    case 'disconnected':
+    case 'error':
+      statusDot.classList.add('bg-red-500');
+      statusText.textContent = text || 'Disconnected';
+      break;
+    default:
+      statusDot.classList.add('bg-gray-400');
+      statusText.textContent = text || 'Unknown';
+  }
+}
+
+// Initialize status indicator
+function initStatusIndicator() {
+  // Set initial state
+  updateStatusIndicator('connecting', 'Connecting...');
+  
+  // Register callback with WebSocket manager when available
+  if (typeof wsManager !== 'undefined' && wsManager) {
+    wsManager.onStatusChange(function(state, text) {
+      updateStatusIndicator(state, text);
+    });
+  } else {
+    // Wait for WebSocket manager to be available
+    var checkInterval = setInterval(function() {
+      if (typeof wsManager !== 'undefined' && wsManager) {
+        wsManager.onStatusChange(function(state, text) {
+          updateStatusIndicator(state, text);
+        });
+        clearInterval(checkInterval);
+      }
+    }, 100);
+  }
+}
+
+// Initialize all header components
+function initHeader() {
+  initClock();
+  initStatusIndicator();
+}
+
+// Cleanup on page unload
+if (typeof window !== 'undefined') {
+  window.addEventListener('beforeunload', function() {
+    if (clockInterval) {
+      clearInterval(clockInterval);
+    }
+  });
+}
--- a/pkg/web/static/js/init.js
+++ b/pkg/web/static/js/init.js
@@ -5,6 +5,38 @@ window.addEventListener('DOMContentLoaded', function() {
  showLoading(true);
  displayExternalIP();
  
+  // Initialize header components (clock and status indicator)
+  if (typeof initHeader === 'function') {
+    initHeader();
+  }
+  
+  // Initialize WebSocket connection and register ban event handler
+  function registerBanEventHandler() {
+    if (typeof wsManager !== 'undefined' && wsManager) {
+      wsManager.onBanEvent(function(event) {
+        if (typeof addBanEventFromWebSocket === 'function') {
+          addBanEventFromWebSocket(event);
+        }
+      });
+      return true;
+    }
+    return false;
+  }
+  
+  if (!registerBanEventHandler()) {
+    // Wait for WebSocket manager to be available
+    var wsCheckInterval = setInterval(function() {
+      if (registerBanEventHandler()) {
+        clearInterval(wsCheckInterval);
+      }
+    }, 100);
+    
+    // Stop checking after 5 seconds
+    setTimeout(function() {
+      clearInterval(wsCheckInterval);
+    }, 5000);
+  }
+  
  // Check LOTR mode on page load to apply immediately
  fetch('/api/settings')
    .then(res => res.json())
@@ -114,4 +146,3 @@ window.addEventListener('DOMContentLoaded', function() {
    }
  });
 });
-
--- a/pkg/web/static/js/websocket.js
+++ b/pkg/web/static/js/websocket.js
@@ -0,0 +1,205 @@
+// WebSocket Manager for Fail2ban UI
+// Handles real-time communication with the backend
+
+"use strict";
+
+class WebSocketManager {
+  constructor() {
+    this.ws = null;
+    this.reconnectAttempts = 0;
+    this.maxReconnectAttempts = Infinity;
+    this.reconnectDelay = 1000; // Start with 1 second
+    this.maxReconnectDelay = 30000; // Max 30 seconds
+    this.isConnecting = false;
+    this.isConnected = false;
+    this.lastBanEventId = null;
+    this.statusCallbacks = [];
+    this.banEventCallbacks = [];
+    
+    // Get WebSocket URL
+    const protocol = window.location.protocol === 'https:' ? 'wss:' : 'ws:';
+    const host = window.location.host;
+    this.wsUrl = `${protocol}//${host}/api/ws`;
+    
+    this.connect();
+  }
+
+  connect() {
+    if (this.isConnecting || (this.ws && this.ws.readyState === WebSocket.OPEN)) {
+      return;
+    }
+
+    this.isConnecting = true;
+    this.updateStatus('connecting', 'Connecting...');
+
+    try {
+      this.ws = new WebSocket(this.wsUrl);
+
+      this.ws.onopen = () => {
+        this.isConnecting = false;
+        this.isConnected = true;
+        this.reconnectAttempts = 0;
+        this.reconnectDelay = 1000;
+        this.updateStatus('connected', 'Connected');
+        console.log('WebSocket connected');
+      };
+
+      this.ws.onmessage = (event) => {
+        try {
+          const message = JSON.parse(event.data);
+          this.handleMessage(message);
+        } catch (err) {
+          console.error('Error parsing WebSocket message:', err);
+        }
+      };
+
+      this.ws.onerror = (error) => {
+        console.error('WebSocket error:', error);
+        this.updateStatus('error', 'Connection error');
+      };
+
+      this.ws.onclose = () => {
+        this.isConnecting = false;
+        this.isConnected = false;
+        this.updateStatus('disconnected', 'Disconnected');
+        console.log('WebSocket disconnected');
+        
+        // Attempt to reconnect
+        if (this.reconnectAttempts < this.maxReconnectAttempts) {
+          this.scheduleReconnect();
+        }
+      };
+    } catch (error) {
+      console.error('Error creating WebSocket connection:', error);
+      this.isConnecting = false;
+      this.updateStatus('error', 'Connection failed');
+      this.scheduleReconnect();
+    }
+  }
+
+  scheduleReconnect() {
+    this.reconnectAttempts++;
+    const delay = Math.min(this.reconnectDelay * Math.pow(2, this.reconnectAttempts - 1), this.maxReconnectDelay);
+    
+    this.updateStatus('reconnecting', 'Reconnecting...');
+    
+    setTimeout(() => {
+      this.connect();
+    }, delay);
+  }
+
+  handleMessage(message) {
+    switch (message.type) {
+      case 'ban_event':
+        this.handleBanEvent(message.data);
+        break;
+      case 'heartbeat':
+        this.handleHeartbeat(message);
+        break;
+      default:
+        console.log('Unknown message type:', message.type);
+    }
+  }
+
+  handleBanEvent(eventData) {
+    // Check if we've already processed this event (prevent duplicates)
+    // Only check if event has an ID and we have a lastBanEventId
+    if (eventData.id && this.lastBanEventId !== null && eventData.id <= this.lastBanEventId) {
+      console.log('Skipping duplicate ban event:', eventData.id);
+      return;
+    }
+
+    // Update lastBanEventId if event has an ID
+    if (eventData.id) {
+      if (this.lastBanEventId === null || eventData.id > this.lastBanEventId) {
+        this.lastBanEventId = eventData.id;
+      }
+    }
+
+    console.log('Processing ban event:', eventData);
+
+    // Notify all registered callbacks
+    this.banEventCallbacks.forEach(callback => {
+      try {
+        callback(eventData);
+      } catch (err) {
+        console.error('Error in ban event callback:', err);
+      }
+    });
+  }
+
+  handleHeartbeat(message) {
+    // Update status to show backend is healthy
+    if (this.isConnected) {
+      this.updateStatus('connected', 'Connected');
+    }
+  }
+
+  updateStatus(state, text) {
+    this.statusCallbacks.forEach(callback => {
+      try {
+        callback(state, text);
+      } catch (err) {
+        console.error('Error in status callback:', err);
+      }
+    });
+  }
+
+  onStatusChange(callback) {
+    this.statusCallbacks.push(callback);
+  }
+
+  onBanEvent(callback) {
+    this.banEventCallbacks.push(callback);
+  }
+
+  disconnect() {
+    if (this.ws) {
+      this.ws.close();
+      this.ws = null;
+    }
+    this.isConnected = false;
+    this.isConnecting = false;
+  }
+
+  getConnectionState() {
+    if (!this.ws) {
+      return 'disconnected';
+    }
+    
+    switch (this.ws.readyState) {
+      case WebSocket.CONNECTING:
+        return 'connecting';
+      case WebSocket.OPEN:
+        return 'connected';
+      case WebSocket.CLOSING:
+        return 'disconnecting';
+      case WebSocket.CLOSED:
+        return 'disconnected';
+      default:
+        return 'unknown';
+    }
+  }
+
+  isHealthy() {
+    return this.isConnected && this.ws && this.ws.readyState === WebSocket.OPEN;
+  }
+}
+
+// Create global instance - initialize immediately
+var wsManager = null;
+
+// Initialize WebSocket manager
+if (typeof window !== 'undefined') {
+  // Initialize immediately if DOM is already loaded, otherwise wait
+  if (document.readyState === 'loading') {
+    document.addEventListener('DOMContentLoaded', function() {
+      if (!wsManager) {
+        wsManager = new WebSocketManager();
+      }
+    });
+  } else {
+    wsManager = new WebSocketManager();
+  }
+}
+
--- a/pkg/web/templates/index.html
+++ b/pkg/web/templates/index.html
@@ -75,12 +75,19 @@
          <div class="flex-shrink-0">
            <span class="text-xl font-bold">Fail2ban UI</span>
          </div>
+          <div id="backendStatus" class="ml-4 flex items-center gap-2">
+            <span class="w-2 h-2 rounded-full bg-gray-400" id="statusDot"></span>
+            <span id="statusText" class="text-xs">Connecting...</span>
+          </div>
        </div>
        <div class="hidden md:block">
-          <div class="ml-10 flex items-baseline space-x-4">
+          <div class="ml-10 flex items-baseline space-x-4 items-center">
            <a href="#" onclick="showSection('dashboardSection')" class="px-3 py-2 rounded-md text-sm font-medium hover:bg-blue-700 transition-colors" data-i18n="nav.dashboard">Dashboard</a>
            <a href="#" onclick="showSection('filterSection')" class="px-3 py-2 rounded-md text-sm font-medium hover:bg-blue-700 transition-colors" data-i18n="nav.filter_debug">Filter Debug</a>
            <a href="#" onclick="showSection('settingsSection')" class="px-3 py-2 rounded-md text-sm font-medium hover:bg-blue-700 transition-colors" data-i18n="nav.settings">Settings</a>
+            <div id="clockDisplay" class="ml-4 text-sm font-mono">
+              <span id="clockTime">--:--:--</span>
+            </div>
          </div>
        </div>
        <div class="md:hidden">
@@ -1163,6 +1170,8 @@
  <script src="/static/js/jails.js"></script>
  <script src="/static/js/settings.js"></script>
  <script src="/static/js/filters.js"></script>
+  <script src="/static/js/websocket.js"></script>
+  <script src="/static/js/header.js"></script>
  <script src="/static/js/lotr.js"></script>
  <script src="/static/js/init.js"></script>
 </body>
--- a/pkg/web/websocket.go
+++ b/pkg/web/websocket.go
@@ -0,0 +1,268 @@
+// Fail2ban UI - A Swiss made, management interface for Fail2ban.
+//
+// Copyright (C) 2025 Swissmakers GmbH (https://swissmakers.ch)
+//
+// Licensed under the GNU General Public License, Version 3 (GPL-3.0)
+// You may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     https://www.gnu.org/licenses/gpl-3.0.en.html
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package web
+
+import (
+	"encoding/json"
+	"log"
+	"net/http"
+	"sync"
+	"time"
+
+	"github.com/gin-gonic/gin"
+	"github.com/gorilla/websocket"
+	"github.com/swissmakers/fail2ban-ui/internal/storage"
+)
+
+const (
+	// Time allowed to write a message to the peer
+	writeWait = 10 * time.Second
+
+	// Time allowed to read the next pong message from the peer
+	pongWait = 60 * time.Second
+
+	// Send pings to peer with this period (must be less than pongWait)
+	pingPeriod = (pongWait * 9) / 10
+
+	// Maximum message size allowed from peer
+	maxMessageSize = 512
+)
+
+var upgrader = websocket.Upgrader{
+	ReadBufferSize:  1024,
+	WriteBufferSize: 1024,
+	CheckOrigin: func(r *http.Request) bool {
+		// Allow all origins for now - can be restricted in production
+		return true
+	},
+}
+
+// Client represents a WebSocket connection
+type Client struct {
+	hub  *Hub
+	conn *websocket.Conn
+	send chan []byte
+}
+
+// Hub maintains the set of active clients and broadcasts messages to them
+type Hub struct {
+	// Registered clients
+	clients map[*Client]bool
+
+	// Inbound messages from clients
+	broadcast chan []byte
+
+	// Register requests from clients
+	register chan *Client
+
+	// Unregister requests from clients
+	unregister chan *Client
+
+	// Mutex for thread-safe operations
+	mu sync.RWMutex
+}
+
+// NewHub creates a new WebSocket hub
+func NewHub() *Hub {
+	return &Hub{
+		clients:    make(map[*Client]bool),
+		broadcast:  make(chan []byte, 256),
+		register:   make(chan *Client),
+		unregister: make(chan *Client),
+	}
+}
+
+// Run starts the hub's main loop
+func (h *Hub) Run() {
+	// Start heartbeat ticker
+	ticker := time.NewTicker(30 * time.Second)
+	defer ticker.Stop()
+
+	for {
+		select {
+		case client := <-h.register:
+			h.mu.Lock()
+			h.clients[client] = true
+			h.mu.Unlock()
+			log.Printf("WebSocket client connected. Total clients: %d", len(h.clients))
+
+		case client := <-h.unregister:
+			h.mu.Lock()
+			if _, ok := h.clients[client]; ok {
+				delete(h.clients, client)
+				close(client.send)
+			}
+			h.mu.Unlock()
+			log.Printf("WebSocket client disconnected. Total clients: %d", len(h.clients))
+
+		case message := <-h.broadcast:
+			h.mu.RLock()
+			for client := range h.clients {
+				select {
+				case client.send <- message:
+				default:
+					close(client.send)
+					delete(h.clients, client)
+				}
+			}
+			h.mu.RUnlock()
+
+		case <-ticker.C:
+			// Send heartbeat to all clients
+			h.sendHeartbeat()
+		}
+	}
+}
+
+// sendHeartbeat sends a heartbeat message to all connected clients
+func (h *Hub) sendHeartbeat() {
+	message := map[string]interface{}{
+		"type":   "heartbeat",
+		"time":   time.Now().UTC().Unix(),
+		"status": "healthy",
+	}
+	data, err := json.Marshal(message)
+	if err != nil {
+		log.Printf("Error marshaling heartbeat: %v", err)
+		return
+	}
+
+	h.mu.RLock()
+	for client := range h.clients {
+		select {
+		case client.send <- data:
+		default:
+			close(client.send)
+			delete(h.clients, client)
+		}
+	}
+	h.mu.RUnlock()
+}
+
+// BroadcastBanEvent broadcasts a ban event to all connected clients
+func (h *Hub) BroadcastBanEvent(event storage.BanEventRecord) {
+	message := map[string]interface{}{
+		"type": "ban_event",
+		"data": event,
+	}
+	data, err := json.Marshal(message)
+	if err != nil {
+		log.Printf("Error marshaling ban event: %v", err)
+		return
+	}
+
+	select {
+	case h.broadcast <- data:
+	default:
+		log.Printf("Broadcast channel full, dropping ban event")
+	}
+}
+
+// readPump pumps messages from the WebSocket connection to the hub
+func (c *Client) readPump() {
+	defer func() {
+		c.hub.unregister <- c
+		c.conn.Close()
+	}()
+
+	c.conn.SetReadDeadline(time.Now().Add(pongWait))
+	c.conn.SetPongHandler(func(string) error {
+		c.conn.SetReadDeadline(time.Now().Add(pongWait))
+		return nil
+	})
+
+	for {
+		_, _, err := c.conn.ReadMessage()
+		if err != nil {
+			if websocket.IsUnexpectedCloseError(err, websocket.CloseGoingAway, websocket.CloseAbnormalClosure) {
+				log.Printf("WebSocket error: %v", err)
+			}
+			break
+		}
+	}
+}
+
+// writePump pumps messages from the hub to the WebSocket connection
+func (c *Client) writePump() {
+	ticker := time.NewTicker(pingPeriod)
+	defer func() {
+		ticker.Stop()
+		c.conn.Close()
+	}()
+
+	for {
+		select {
+		case message, ok := <-c.send:
+			c.conn.SetWriteDeadline(time.Now().Add(writeWait))
+			if !ok {
+				c.conn.WriteMessage(websocket.CloseMessage, []byte{})
+				return
+			}
+
+			w, err := c.conn.NextWriter(websocket.TextMessage)
+			if err != nil {
+				return
+			}
+			w.Write(message)
+
+			// Add queued messages to the current websocket message
+			n := len(c.send)
+			for i := 0; i < n; i++ {
+				w.Write([]byte{'\n'})
+				w.Write(<-c.send)
+			}
+
+			if err := w.Close(); err != nil {
+				return
+			}
+
+		case <-ticker.C:
+			c.conn.SetWriteDeadline(time.Now().Add(writeWait))
+			if err := c.conn.WriteMessage(websocket.PingMessage, nil); err != nil {
+				return
+			}
+		}
+	}
+}
+
+// serveWS handles WebSocket requests from clients
+func serveWS(hub *Hub, c *gin.Context) {
+	conn, err := upgrader.Upgrade(c.Writer, c.Request, nil)
+	if err != nil {
+		log.Printf("WebSocket upgrade error: %v", err)
+		return
+	}
+
+	client := &Client{
+		hub:  hub,
+		conn: conn,
+		send: make(chan []byte, 256),
+	}
+
+	client.hub.register <- client
+
+	// Allow collection of memory referenced by the caller by doing all work in new goroutines
+	go client.writePump()
+	go client.readPump()
+}
+
+// WebSocketHandler is the Gin handler for WebSocket connections
+func WebSocketHandler(hub *Hub) gin.HandlerFunc {
+	return func(c *gin.Context) {
+		serveWS(hub, c)
+	}
+}