Update vpn_connection_detector.dart

[flareso]

Enhance VPN Detection Logic and Real-Time Stream Integration

Summary:

This PR significantly improves the VPN detection logic by adding a robust and dynamic VpnConnectionDetector class. The changes provide a real-time stream to monitor VPN connection states and include enhanced flexibility for detecting various VPN types across platforms.

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Key Changes:

1. New VpnConnectionDetector Class:

   • Introduced a singleton class that allows real-time VPN detection using network interfaces.
   • The class checks network interfaces for common VPN-related patterns (tun, tap, vpn, etc.) to determine if a VPN is active.
   • VPN detection is triggered by both network connectivity changes and periodic checks every 30 seconds.

2. Real-Time VPN Connection State Stream:

   • Developers can subscribe to vpnConnectionStream to listen for updates on whether a VPN connection is active or disconnected.
   • The stream is broadcast-based, allowing multiple listeners.

3. Custom VPN Pattern Support:

   • The addVpnPattern() method enables developers to add custom VPN interface patterns dynamically to account for unique VPN implementations.

4. Static Method for One-Time VPN Checks:

   • Added isVpnActive() as a static method for cases where a one-time VPN status check is needed, without subscribing to the stream.

5. Optimized Resource Management:

   • Proper resource management is implemented with a dispose() method that cleans up stream controllers, connectivity subscriptions, and timers.

6. Extensive Documentation:

   • Included comprehensive inline documentation for easier integration and understanding of the class functionality.

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Example Usage:

final vpnDetector = VpnConnectionDetector();

// Listen for real-time VPN connection state changes
vpnDetector.vpnConnectionStream.listen((state) {
  if (state == VpnConnectionState.connected) {
    print("VPN is connected.");
  } else {
    print("VPN is disconnected.");
  }
});

// One-time check for VPN connection
bool isVpnActive = await VpnConnectionDetector.isVpnActive();
print('VPN active: $isVpnActive');

// Add custom VPN pattern if needed
vpnDetector.addVpnPattern('customvpn');

// Clean up resources when done
vpnDetector.dispose();

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Benefits:

• Cross-platform support: Works across Android, iOS, macOS, and other platforms using the NetworkInterface API.
• Real-time detection: Ensures that changes in VPN status are captured instantly or within the 30-second interval.
• Customizable: Allows developers to extend the detection capabilities by adding their own patterns for VPN interfaces.
• Lightweight: Optimized to handle periodic checks and network changes without impacting app performance.

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Next Steps:

• Review the changes for cross-platform compatibility.
• Merge into the main branch to allow other developers to start leveraging real-time VPN detection.

Looking forward to feedback and suggestions!