flutter_ulink_sdk 0.1.3

Flutter SDK for creating and handling dynamic links, similar to Branch.io

ULink SDK for Flutter

A Flutter SDK for creating and handling dynamic links with ULink, similar to Branch.io.

Features

• Create dynamic links with custom slugs and parameters
• Social media tag support for better link sharing
• Automatic handling of dynamic links in your app
• Graceful handling of unified/simple links with automatic external redirection
• Resolve links to retrieve their data
• Session tracking and analytics
• Device information collection
• Installation tracking
• Clear distinction between dynamic and unified link types

Installation

Add this to your pubspec.yaml dependencies:

dependencies:
  flutter_ulink_sdk: ^1.0.0

Configuration

1. ULink Dashboard Configuration

Before setting up your mobile apps, you need to configure your project in the ULink dashboard:

1. Visit the ULink website to register for an account and create a project
2. Reserve your subdomain on shared.ly through the ULink service

Android Configuration

1. Log in to the ULink dashboard and navigate to your project
2. Go to the "Configure" section and select the "Android" tab
3. Fill in the following information:
   • Package Name: Enter your Android app's package name (e.g., com.yourcompany.app)
   • Deep Linking Schema: Enter your app's URI scheme ending with "://" (e.g., yourappscheme://)
   • SHA-256 Certificate Fingerprints: Add the SHA-256 fingerprint of your app signing key
4. Save your changes

iOS Configuration

1. In the ULink dashboard, select the "iOS" tab
2. Fill in the following information:
   • Bundle Identifier: Enter your iOS app's bundle identifier (e.g., com.yourcompany.app)
   • Deep Linking Schema: Enter your app's URI scheme ending with "://" (same as Android)
   • Team ID: Enter your Apple Developer Team ID
3. Save your changes

Note: The deep linking schema must end with :// and can be any identifier you choose (e.g., acmeshop://). You will use the same schema in both platforms.

2. Native App Configuration

After configuring your project in the ULink dashboard, you need to set up your native app projects:

Android Setup

1. Open your Android project's AndroidManifest.xml file
2. Add the following intent filters inside your main activity tag:

<!-- 
    Note: Your project may already have an activity defined with intent filters.
    In that case, don't add a new activity - instead, add these intent filters
    to your existing main activity, preserving any other intent filters you already have.
-->
<activity
    android:name="io.flutter.embedding.android.FlutterActivity"
    android:launchMode="singleTop"
    android:theme="@style/LaunchTheme"
    android:configChanges="orientation|keyboardHidden|keyboard|screenSize|locale|layoutDirection|fontScale|screenLayout|density|uiMode"
    android:hardwareAccelerated="true"
    android:windowSoftInputMode="adjustResize">
    
    <!-- Your other intent filters, if any, should remain here -->
    
    <!-- Deep Link handling -->
    <intent-filter>
        <action android:name="android.intent.action.VIEW" />
        <category android:name="android.intent.category.DEFAULT" />
        <category android:name="android.intent.category.BROWSABLE" />
        
        <!-- Replace with your app's scheme from ULink project (must end with "://") -->
        <data android:scheme="yourappname" />
    </intent-filter>
    
    <!-- Domain Link handling (for Universal Links) -->
    <intent-filter android:autoVerify="true">
        <action android:name="android.intent.action.VIEW" />
        <category android:name="android.intent.category.DEFAULT" />
        <category android:name="android.intent.category.BROWSABLE" />
        
        <!-- Replace with your subdomain on shared.ly from ULink -->
        <data android:scheme="https" android:host="yourdomain.shared.ly" />
    </intent-filter>
</activity>

Note: The domain configuration including required files in the .well-known directory is automatically handled when you register your subdomain on shared.ly through the ULink service.

iOS Setup

1. Open your iOS project in Xcode

2. Go to your project's target settings

3. Select the "Info" tab

4. Add a new entry to URL Types:

   • Identifier: bundle id (e.g., com.example.app)
   • URL Schemes: yourappname (the scheme you configured in ULink, without the "://")

5. Add Associated Domains capability:

   • Go to the "Signing & Capabilities" tab
   • Click the "+" button to add a capability
   • Select "Associated Domains"
   • Add applinks:yourdomain.shared.ly

Note: The domain configuration including required files in the .well-known directory is automatically handled when you register your subdomain on shared.ly through the ULink service.

3. Flutter SDK Initialization

Initialize the SDK in your app:

import 'package:flutter_ulink_sdk/flutter_ulink_sdk.dart';

void main() async {
  WidgetsFlutterBinding.ensureInitialized();
  
  // Initialize with production defaults
  final ulink = await ULink.initialize();
  
  // Or with custom config
  final ulink = await ULink.initialize(
    config: ULinkConfig(
      apiKey: 'your_api_key',
      debug: true, // Enable debug logging
    ),
  );
  
  runApp(MyApp());
}

Link Types

The ULink SDK supports two distinct types of links:

Dynamic Links

• Purpose: App deep linking with parameters, fallback URLs, and smart app store redirects
• Handling: Processed in-app with custom parameters and navigation logic
• Type: Automatically determined as dynamic by server

Unified/Simple Links

• Purpose: Simple platform-based redirects for browser handling
• Handling: Automatically redirected externally when opened in-app
• Type: Determined from server response type field

Key Benefit: Simple links maintain their browser-based behavior even when accidentally opened in your app, providing seamless user experience.

For detailed information, see UNIFIED_LINKS.md.

Creating Links

Dynamic Links (In-App Handling)

// Create a dynamic link (for in-app handling)
final dynamicResponse = await ULink.instance.createLink(
  ULinkParameters.dynamic(
    slug: 'my-dynamic-link',
    iosFallbackUrl: 'https://apps.apple.com/app/myapp',
    androidFallbackUrl: 'https://play.google.com/store/apps/details?id=com.myapp',
    fallbackUrl: 'https://example.com/profile',
    parameters: {
      'screen': 'profile',
      'userId': '12345',
      'utm_source': 'app',
    },
    socialMediaTags: SocialMediaTags(
      ogTitle: 'Check out this amazing app!',
      ogDescription: 'The best app for managing your tasks',
      ogImage: 'https://example.com/image.jpg',
    ),
  ),
);

if (dynamicResponse.success) {
  print('Dynamic link created: ${dynamicResponse.url}');
} else {
  print('Error: ${dynamicResponse.error}');
}

Unified Links (External Redirect)

// Create a unified link (for external redirects)
final unifiedResponse = await ULink.instance.createLink(
  ULinkParameters.unified(
    slug: 'my-unified-link',
    iosUrl: 'https://apps.apple.com/app/my-app/id123456789',
    androidUrl: 'https://play.google.com/store/apps/details?id=com.example.myapp',
    fallbackUrl: 'https://myapp.com/product/123',
    parameters: {
      'utm_source': 'email',
      'campaign': 'summer',
    },
    metadata: {
      'custom_param': 'value',
    },
  ),
);

if (unifiedResponse.success) {
  print('Unified link created: ${unifiedResponse.url}');
} else {
  print('Error: ${unifiedResponse.error}');
}

Factory Methods for Cleaner API

The ULink SDK provides factory methods for creating different types of links, making the API more intuitive and type-safe:

ULinkParameters.dynamic()

Creates dynamic links for in-app deep linking:

• Purpose: In-app deep linking with parameters and smart app store redirects
• Required fields: None (all optional)
• Fallback fields: iosFallbackUrl, androidFallbackUrl, fallbackUrl
• Additional: parameters for custom data, socialMediaTags for sharing

ULinkParameters.unified()

Creates unified links for external redirects:

• Purpose: Simple platform-based redirects for marketing campaigns
• Required fields: iosUrl, androidUrl
• Platform URLs: iosUrl, androidUrl, fallbackUrl
• Additional: parameters for tracking, metadata for custom data

Benefits of Factory Methods

• Type Safety: Ensures correct fields are used for each link type
• Cleaner Code: No need to manually specify type parameter
• Better IDE Support: Auto-completion shows only relevant parameters
• Reduced Errors: Prevents mixing dynamic and unified link parameters

Automatic Session Management

The ULink SDK automatically manages user sessions based on your app's lifecycle states. No manual session tracking is required - the SDK handles this seamlessly for both iOS and Android.

How It Works

• App Launch: A new session starts automatically when the SDK is initialized
• App Resume: When your app comes to the foreground, a new session starts if none exists
• App Pause/Background: When your app goes to the background, the current session ends automatically
• App Termination: Sessions are properly ended when the app is destroyed

Automatic Lifecycle Events

The SDK responds to these app lifecycle states:

• resumed - Starts a new session if none exists
• paused - Ends the current session
• inactive - Ends the current session
• detached - Ends the current session
• hidden - Ends the current session

Manual Session Control (Optional)

While automatic session management handles most use cases, you can still manually control sessions if needed:

// Check if a session is active
if (ULink.instance.hasActiveSession()) {
  print('Session ID: ${ULink.instance.getCurrentSessionId()}');
}

// Manually start a session with custom metadata
final sessionResponse = await ULink.instance.startSession(
  metadata: {
    'user_type': 'premium',
    'app_version': '1.2.0',
  },
);

// Manually end the current session
final endResponse = await ULink.instance.endSession();

Benefits

• Zero Configuration: Works out of the box without any setup
• Cross-Platform: Consistent behavior on both iOS and Android
• Accurate Analytics: Proper session tracking for better insights
• Battery Efficient: Sessions end when app is not in use
• Developer Friendly: No need to track app lifecycle manually

Handling Dynamic Links

Listen for dynamic links in your app:

@override
void initState() {
  super.initState();
  
  // Listen for dynamic links (in-app handling)
  ULink.instance.onLink.listen((ULinkResolvedData data) {
    setState(() {
      // Access link data
      final slug = data.slug;
      final fallbackUrl = data.fallbackUrl;
      final parameters = data.parameters;
      final socialMediaTags = data.socialMediaTags;
      final rawData = data.rawData;
      
      print('Received dynamic link: ${data.rawData}');
      print('Dynamic link parameters: ${data.parameters}');
      // Handle dynamic link with custom logic
      
      // Navigate based on parameters
      if (parameters != null) {
        final screen = parameters['screen'];
        final userId = parameters['userId'];
        
        if (screen == 'profile' && userId != null) {
          // Navigate to profile screen
        }
      }
    });
  });
  
  // Listen for unified links (external redirects)
  ULink.instance.onUnifiedLink.listen((ULinkResolvedData data) {
    print('Unified link received and redirected externally: ${data.rawData}');
    // Optional: Track unified link events for analytics
  });
}

Resolving Links Manually

Resolve a dynamic link to get its data:

// Resolve a ULink format URL (slug)
final resolveResponse = await ULink.instance.resolveLink('https://ulink.shared.ly/your-slug');

if (resolveResponse.success) {
  final resolvedData = ULinkResolvedData.fromJson(resolveResponse.data!);
  // Use the resolved data
  print('Slug: ${resolvedData.slug}');
  print('Fallback URL: ${resolvedData.fallbackUrl}');
  print('Parameters: ${resolvedData.parameters}');
} else {
  // Handle error
  print('Error: ${resolveResponse.error}');
}

Example Project

Check out the example project in the example directory for a complete implementation.

License

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