Ws.Maui.LocalDB.Sync

Ws.Maui.LocalDB.Sync is a lightweight, modular sync library for .NET MAUI apps that need offline-first functionality. It provides an extensible and testable mechanism to sync remote data with a local SQLite database using a clean and pluggable architecture.

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🌟 Features

• ✅ Sync remote data into a local SQLite database
• 🔄 Conflict resolution strategies (Prefer Local, Prefer Remote, Custom Merge)
• 🧹 Optional TTL (time-to-live) data pruning support
• 📡 Incremental sync support (Last-Modified or ETag ready)
• 🔁 Retry logic for remote fetch/save operations
• ⚙️ Works great with .NET MAUI and SQLite-net-pcl

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📦 Installation

dotnet add package Ws.Maui.LocalDB.Sync

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🧩 Basic Usage

1. Implement Your Entity

public class Article : ISyncableEntity<Guid>
{
    public Guid Id { get; set; }
    public DateTime LastModified { get; set; }
    public string Title { get; set; }
    public string Content { get; set; }
}

2. Initialize a SQLiteStore

var store = new SQLiteStore<Article, Guid>("path/to/your.db");

3. Create Your SyncManager

var manager = new SyncManager<Article, Guid>(
    fetchRemote: async () => await remoteService.GetArticlesAsync(),
    fetchLocal: store.GetAllAsync,
    saveLocal: store.SaveAsync,
    resolveConflict: new PreferRemoteStrategy<Article>().Resolve
);

var results = await manager.SyncAsync();

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🔄 Incremental Sync Support (Advanced)

Supports tracking the last sync timestamp using ISyncMetadataProvider:

public interface ISyncMetadataProvider<TKey>
{
    Task<DateTime?> GetLastSyncedUtcAsync(TKey scope);
    Task SetLastSyncedUtcAsync(TKey scope, DateTime timestamp);
}

Pass it into the SyncManager constructor to enable automatic timestamp tracking.

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🧼 TTL Policies (Optional Pruning)

Use ITtlPolicy<T> to delete expired records automatically:

public class ArticleTtlPolicy : ITtlPolicy<Article>
{
    public bool ShouldDelete(Article article) =>
        article.LastModified < DateTime.UtcNow.AddDays(-30);
}

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🔁 Retry & Error Handling

All fetch/save operations can be wrapped with retry logic to improve resilience:

await RetryHelper.ExecuteWithRetry(() => store.SaveAsync(items));

Each SyncResult<T> contains an Exception? Error field to track failed operations.

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✅ To Do

• TTL Pruning Support
• Retry + Error Tracking
• Incremental Sync via Metadata
• NuGet Packaging & Versioning
• Platform-specific samples (Android, Windows, etc)

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📄 License

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

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💬 Contributing

Contributions and suggestions are welcome! Please open an issue or submit a pull request.

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🙌 Credits

Built with ❤️ for developers who need reliable offline sync in cross-platform apps.

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