Add browser support with Socket.io transport, authentication, performance-optimized IPC, and CI/CD

.devcontainer/devcontainer.json

@@ -0,0 +1,46 @@
+{
+  "name": "MQTT Explorer Development",
+  "dockerComposeFile": "docker-compose.yml",
+  "service": "app",
+  "workspaceFolder": "/workspace",
+
+  "customizations": {
+    "vscode": {
+      "extensions": [
+        "dbaeumer.vscode-eslint",
+        "esbenp.prettier-vscode",
+        "ms-vscode.vscode-typescript-next",
+        "ms-azuretools.vscode-docker",
+        "eamodio.gitlens"
+      ],
+      "settings": {
+        "editor.formatOnSave": true,
+        "editor.defaultFormatter": "esbenp.prettier-vscode",
+        "typescript.tsdk": "node_modules/typescript/lib",
+        "editor.codeActionsOnSave": {
+          "source.fixAll.eslint": "explicit"
+        }
+      }
+    }
+  },
+
+  "forwardPorts": [3000, 8080, 1883],
+  "portsAttributes": {
+    "3000": {
+      "label": "MQTT Explorer Server",
+      "onAutoForward": "notify"
+    },
+    "8080": {
+      "label": "Webpack Dev Server",
+      "onAutoForward": "notify"
+    },
+    "1883": {
+      "label": "MQTT Broker",
+      "onAutoForward": "ignore"
+    }
+  },
+
+  "postCreateCommand": "yarn install",
+
+  "remoteUser": "node"
+}

.devcontainer/docker-compose.yml

@@ -0,0 +1,21 @@
+version: '3.8'
+
+services:
+  app:
+    image: mcr.microsoft.com/devcontainers/javascript-node:20
+    volumes:
+      - ../..:/workspace:cached
+    command: sleep infinity
+    network_mode: service:mosquitto
+    environment:
+      - MQTT_EXPLORER_USERNAME=dev
+      - MQTT_EXPLORER_PASSWORD=dev123
+
+  mosquitto:
+    image: eclipse-mosquitto:2
+    ports:
+      - "1883:1883"
+      - "3000:3000"
+      - "8080:8080"
+    volumes:
+      - ./mosquitto.conf:/mosquitto/config/mosquitto.conf:ro

.devcontainer/mosquitto.conf

@@ -0,0 +1,4 @@
+# Mosquitto configuration for development
+listener 1883
+allow_anonymous true
+persistence false

.github/copilot-instructions.md

@@ -25,6 +25,10 @@ yarn install
 # Build the project
 yarn build
 
+# Set password for browser testing
+export MQTT_EXPLORER_USERNAME=admin
+export MQTT_EXPLORER_PASSWORD=secretpassword
+
 # Start the application
 yarn start
 
@@ -322,5 +326,5 @@ yarn package-with-docker
 - The app uses Electron (see `package.json` for version)
 - MQTT communication is handled via [mqttjs](https://github.com/mqttjs/MQTT.js)
 - All code changes should pass linting (`yarn lint`)
-- Node.js version requirement: >= 18
+- Node.js version requirement: >= 20
 - The project uses workspace-like structure with separate package.json files for app and backend

.github/workflows/copilot-setup.yml

@@ -14,7 +14,7 @@ jobs:
       - name: Setup Node.js
         uses: actions/setup-node@v4
         with:
-          node-version: '18'
+          node-version: '20'
 
       - name: Get yarn cache directory path
         id: yarn-cache-dir-path

.github/workflows/tests.yml

@@ -74,3 +74,53 @@ jobs:
         run: echo '${{ steps.upload.outputs.file-url }}'
         id: artifact-upload-step
       - run: echo '<picture><img src="${{ steps.upload.outputs.file-url }}"></picture>' >> $GITHUB_STEP_SUMMARY
+
+  test-browser:
+    runs-on: ubuntu-latest
+    services:
+      mosquitto:
+        image: eclipse-mosquitto:2
+        ports:
+          - 1883:1883
+        options: >-
+          --health-cmd "mosquitto_sub -t '$SYS/#' -C 1"
+          --health-interval 10s
+          --health-timeout 5s
+          --health-retries 5
+    steps:
+      - uses: actions/checkout@v4
+      - name: Setup Node.js
+        uses: actions/setup-node@v4
+        with:
+          node-version: '20'
+      - name: Install Dependencies
+        run: yarn install --frozen-lockfile
+      - name: Build Browser Mode
+        run: yarn build:server
+      - name: Test App
+        run: yarn test:app
+      - name: Test Backend
+        run: yarn test:backend
+      - name: Start Server in Background
+        run: |
+          yarn start:server &
+          echo $! > server.pid
+        env:
+          MQTT_EXPLORER_USERNAME: test
+          MQTT_EXPLORER_PASSWORD: test123
+          PORT: 3000
+      - name: Wait for Server
+        run: |
+          timeout 30 bash -c 'until curl -f http://localhost:3000; do sleep 1; done'
+      - name: Browser Smoke Test
+        run: |
+          # Test server is running
+          curl -f http://localhost:3000 || exit 1
+          echo "Browser mode server is running successfully"
+      - name: Stop Server
+        if: always()
+        run: |
+          if [ -f server.pid ]; then
+            kill $(cat server.pid) || true
+            rm server.pid
+          fi

.gitignore

@@ -15,5 +15,5 @@ mqtt-explorer-mcp-screenshot.png
 screenshot-mcp-*.png
 test-mcp-introspection.js
 
-# UI test artifacts
+/data
 test-screenshot-*.png

BROWSER_MODE.md

@@ -0,0 +1,193 @@
+# Browser Mode Documentation
+
+MQTT Explorer now supports running as a web application served by a Node.js server, in addition to the existing Electron desktop app.
+
+## Running in Browser Mode
+
+### Quick Start
+
+1. Build the application for browser mode:
+   ```bash
+   yarn build:server
+   ```
+
+2. Start the server:
+   ```bash
+   yarn start:server
+   ```
+
+3. Open your browser and navigate to `http://localhost:3000`
+
+4. You'll be prompted to log in with credentials that were generated on server startup.
+
+### Development Mode
+
+To run in development mode with hot reload:
+
+```bash
+yarn dev:server
+```
+
+This starts both the webpack dev server and the backend server.
+
+## Authentication
+
+### Environment Variables
+
+You can set custom authentication credentials using environment variables:
+
+```bash
+export MQTT_EXPLORER_USERNAME=admin
+export MQTT_EXPLORER_PASSWORD=secretpassword
+yarn start:server
+```
+
+### Generated Credentials
+
+If no environment variables are set, the server will generate credentials on first startup and save them to `data/credentials.json`. The generated credentials will be printed to the console:
+
+```
+============================================================
+Generated new credentials:
+Username: user-abc123
+Password: 123e4567-e89b-12d3-a456-426614174000
+============================================================
+Please save these credentials. They will be persisted to:
+/path/to/data/credentials.json
+============================================================
+```
+
+## Features
+
+### Certificate Upload
+
+In browser mode, certificate files are uploaded directly through the browser using the HTML5 File API. The certificates are:
+- Read client-side as base64
+- Stored in the connection configuration
+- Used when establishing MQTT connections
+
+### Data Storage
+
+In browser mode, all data is stored on the server:
+- Credentials: `data/credentials.json`
+- Uploaded certificates: `data/certificates/`
+- File uploads: `data/uploads/`
+
+### Port Configuration
+
+The default port is 3000. You can change it using the `PORT` environment variable:
+
+```bash
+PORT=8080 yarn start:server
+```
+
+## Architecture
+
+### Client-Server Communication
+
+- **Electron Mode**: Uses Electron IPC for communication between renderer and main process
+- **Browser Mode**: Uses Socket.io WebSockets for real-time communication between browser and server
+
+The application automatically detects the environment and uses the appropriate transport layer.
+
+### Event Bus Abstraction
+
+Both Electron IPC and Socket.io implement the same `EventBusInterface`, allowing the application code to work seamlessly in both modes without modification.
+
+## Differences from Electron Mode
+
+### Browser Mode Limitations
+
+1. **File System Access**: Limited to server-side operations
+2. **Native Dialogs**: File selection uses browser file input instead of native dialogs
+3. **Auto-Updates**: Not available in browser mode
+4. **Tray Icon**: Not available in browser mode
+
+### Browser Mode Advantages
+
+1. **No Installation**: Access from any browser
+2. **Cross-Platform**: Works on any device with a modern browser
+3. **Remote Access**: Can be deployed on a server for remote access
+4. **Multi-User**: Can support authentication for multiple users
+
+## Security Considerations
+
+1. **HTTPS**: For production, always use HTTPS to encrypt credentials and MQTT data
+2. **Authentication**: Keep credentials secure and rotate them regularly
+3. **Network**: Ensure the server is on a trusted network or behind a firewall
+4. **Environment Variables**: Use environment variables for production credentials, not the generated ones
+
+## Deployment
+
+For production deployment:
+
+1. Build the application:
+   ```bash
+   yarn build:server
+   ```
+
+2. Set environment variables:
+   ```bash
+   export MQTT_EXPLORER_USERNAME=your_username
+   export MQTT_EXPLORER_PASSWORD=your_secure_password
+   export PORT=3000
+   ```
+
+3. Start the server:
+   ```bash
+   yarn start:server
+   ```
+
+4. Use a reverse proxy (nginx, Apache) to add HTTPS and additional security features
+
+## Troubleshooting
+
+### Debugging
+
+Enable detailed Socket.IO connection and lifecycle debugging:
+
+```bash
+DEBUG=mqtt-explorer:socketio* yarn start:server
+```
+
+Available debug namespaces:
+- `mqtt-explorer:socketio` - General Socket.IO events and metrics
+- `mqtt-explorer:socketio:connect` - Client connection events
+- `mqtt-explorer:socketio:disconnect` - Client disconnection and cleanup
+- `mqtt-explorer:socketio:subscriptions` - Subscription lifecycle tracking
+- `mqtt-explorer:socketio:connections` - MQTT connection ownership
+
+This will log:
+- Client connect/disconnect events
+- Subscription counts per socket
+- MQTT connection ownership tracking
+- Memory leak detection metrics (subscriptions, handlers, connections)
+
+Example output:
+```
+mqtt-explorer:socketio:connect Client connected: abc123de
+mqtt-explorer:socketio [connect] clients=1 subscriptions=8 mqttConns=0 | socket[abc123de]: subs=8 conns=0
+mqtt-explorer:socketio:connections Connection my-mqtt owned by socket abc123de (total: 1)
+mqtt-explorer:socketio:disconnect Client disconnected: abc123de
+mqtt-explorer:socketio:subscriptions Removed 8 subscriptions for socket abc123de
+mqtt-explorer:socketio [disconnect] clients=0 subscriptions=0 mqttConns=0 | socket[abc123de]: subs=0 conns=0
+```
+
+### Authentication Fails
+
+1. Check the console output for the generated credentials
+2. Clear browser session storage: `sessionStorage.clear()` in browser console
+3. Restart the server to regenerate credentials
+
+### Connection Issues
+
+1. Check that the server is running: `http://localhost:3000`
+2. Check browser console for Socket.io connection errors
+3. Verify firewall rules allow the port
+
+### Certificate Upload Issues
+
+In browser mode, certificates are handled differently:
+- Use the file upload button to select certificate files
+- Files are read and encoded client-side
+- Large certificate files (>16KB) will be rejected