Internet Connection CS

A Flutter package to check internet connectivity using pure Dart features without external dependencies.

Features

• ✅ No external dependencies - Uses only Dart's built-in features
• ✅ DNS Lookup based checks using InternetAddress.lookup() with real connectivity verification
• ✅ Socket based checks for faster, lightweight connectivity testing
• ✅ Accurate detection - Correctly identifies when device is on local network but cannot reach internet
• ✅ True reachability test - DNS lookup followed by actual socket connection to verify host accessibility
• ✅ Configurable timeout duration
• ✅ Simple boolean and enum-based status returns
• ✅ Continuous monitoring with streams
• ✅ Singleton pattern for efficient resource usage
• ✅ Comprehensive error handling
• ✅ URL parsing and domain extraction

Installation

Add this to your package's pubspec.yaml file:

dependencies:
  internet_connection_cs: ^1.0.0

Then run:

flutter pub get

Usage

Basic Usage (DNS Lookup with Real Connectivity Verification)

import 'package:internet_connection_cs/internet_connection_cs.dart';

// Get the singleton instance
final connectionChecker = InternetConnectionChecker();

// Check connectivity using DNS lookup + real connection test (default: google.com)
// This performs DNS resolution AND verifies actual host reachability
final status = await connectionChecker.checkConnectivity();
print('Status: $status'); // Status: InternetConnectionStatus.connected

// Check connectivity and get boolean result
final hasConnection = await connectionChecker.hasConnection();
print('Has connection: $hasConnection'); // Has connection: true

Custom Host and Timeout

// Check with custom domain
final status = await connectionChecker.checkConnectivity(
  host: 'github.com', // Domain name only
  timeout: Duration(seconds: 5),
);

// URLs are automatically parsed to extract domain
final urlStatus = await connectionChecker.checkConnectivity(
  host: 'https://www.cloudflare.com/path', // Will use 'www.cloudflare.com'
  timeout: Duration(seconds: 3),
);

final hasConnection = await connectionChecker.hasConnection(
  host: 'api.example.com',
  timeout: Duration(seconds: 3),
);

Socket-based Connectivity (Faster & Lightweight)

// Socket-based check (faster, uses less data)
final socketStatus = await connectionChecker.checkConnectivitySocket();
print('Socket status: $socketStatus');

// Socket check with boolean result
final hasSocketConnection = await connectionChecker.hasConnectionSocket();
print('Has socket connection: $hasSocketConnection');

// Custom socket parameters (IP address and port)
final customSocketStatus = await connectionChecker.checkConnectivitySocket(
  host: '1.1.1.1', // Cloudflare DNS IP
  port: 53,         // DNS port
  timeout: Duration(seconds: 2),
);

Continuous Monitoring

// DNS-based monitoring
connectionChecker.onStatusChange(
  interval: Duration(seconds: 10),
  host: 'google.com',
  timeout: Duration(seconds: 3),
).listen((status) {
  if (status.isConnected) {
    print('Internet is available');
  } else {
    print('No internet connection');
  }
});

// Socket-based monitoring (faster)
connectionChecker.onStatusChangeSocket(
  interval: Duration(seconds: 5),
  host: '8.8.8.8',
  port: 53,
  timeout: Duration(seconds: 1),
).listen((status) {
  print('Socket status: $status');
});

Using Status Extensions

final status = await connectionChecker.checkConnectivity();

if (status.isConnected) {
  // Internet is available
  print('Connected to internet');
} else if (status.isDisconnected) {
  // No internet connection
  print('No internet connection');
} else if (status.isUnknown) {
  // Status is unknown
  print('Connection status unknown');
}

InternetConnectionStatus Enum

The package provides an enum to represent connection status:

enum InternetConnectionStatus {
  connected,    // Internet connection is available
  disconnected, // Internet connection is not available
  unknown       // Internet connection status is unknown
}

Extension Methods

The enum comes with useful extension methods:

• isConnected: Returns true if connected
• isDisconnected: Returns true if disconnected
• isUnknown: Returns true if status is unknown

API Reference

InternetConnectionChecker

Methods

checkConnectivity({String host, Duration timeout})

Checks internet connectivity using DNS lookup followed by real socket connection test. This ensures accurate detection by verifying both DNS resolution AND actual host reachability.

Parameters:

• host (optional): The domain name to check against. Default: 'google.com'
• timeout (optional): Request timeout duration. Default: Duration(seconds: 10)

Returns: Future<InternetConnectionStatus>

Behavior:

• Performs DNS lookup to resolve domain to IP address
• Attempts actual socket connection to verify host is reachable
• Returns connected only if both DNS resolution and connection succeed
• Returns disconnected if device is on local network but cannot reach internet

hasConnection({String host, Duration timeout})

Checks internet connectivity and returns a boolean.

Parameters:

• host (optional): The host URL to check against. Default: 'https://www.google.com'
• timeout (optional): Request timeout duration. Default: Duration(seconds: 10)

Returns: Future<bool>

onStatusChange({Duration interval, String host, Duration timeout})

Creates a stream that periodically checks connectivity.

Parameters:

• interval (optional): How often to check. Default: Duration(seconds: 30)
• host (optional): The host URL to check against. Default: 'https://www.google.com'
• timeout (optional): Request timeout duration. Default: Duration(seconds: 10)

Returns: Stream<InternetConnectionStatus>

Error Handling

The package handles various error scenarios:

• Network unreachable: Returns disconnected
• Timeout: Returns disconnected
• HTTP errors: Returns disconnected
• Invalid URL format: Throws ArgumentError
• Empty host: Throws ArgumentError

Example

See the example file for a complete usage example.

Testing

Run tests with:

flutter test

Contributing

Contributions are welcome! Please read our contributing guidelines and submit pull requests to our repository.

License

This project is licensed under the MIT License - see the LICENSE file for details.