Tenowg.MongoObjects 0.2.0-alpha

MongoObject

A modern MongoDB ODM for .NET 10 with source generation and automatic change tracking.

Overview

MongoObject bridges the gap between MongoDB's document model and modern .NET development. Using Roslyn source generators and C# 14 partial properties, it provides an intuitive, EF Core-like experience for working with MongoDB documents.

Key Features

• 🚀 Source Generation - Automatic implementation via [MongoObject] attribute
• 📊 Change Tracking - Automatic property change detection for efficient updates
• 📝 Metadata Support - Separate metadata types for versioning, timestamps, and ownership
• 🔍 Type-Safe Queries - Generated search classes for compile-time query validation
• 🎯 Projections - Selective field retrieval with [ProjectValue] attribute
• 🔒 Distributed Locking - Document-level concurrency control
• ⚡ Caching - Built-in memory caching with configurable expiration
• 👁️ Change Streams - Real-time MongoDB change monitoring

Installation

The Tenowg.MongoObjects package is currently in active development.

dotnet add package Tenowg.MongoObjects --version 0.1.0-alpha

# Clone the repository
git clone https://github.com/tenowg/MongoObject.git

# Add project reference to your .csproj
<ProjectReference Include="path/to/MongoObject.Core/MongoObject.Core.csproj" />

Quick Start

1. Define Your Document

using MongoObject.Core.Attributes;

// Define optional metadata type
public partial record UserMeta
{
    public string? CreatedBy { get; set; }
    public string? Department { get; set; }
}

// Define your document class
[MongoObject(
    CollectionName = "Users",
    DatabaseName = "MyApp",
    MetadataType = typeof(UserMeta)
)]
public partial class User
{
    public partial string Name { get; set; }
    public partial string Email { get; set; }
    public partial int Age { get; set; }
    public partial Address Address { get; set; }
    public partial List<string> Roles { get; set; }
}

public class Address
{
    public string Street { get; set; }
    public string City { get; set; }
    public string Country { get; set; }
}

2. Register in Dependency Injection

using MongoObject.Core.Extensions;

var builder = Host.CreateDefaultBuilder(args)
    .ConfigureServices((_, services) =>
    {
        services.AddMongoObject(options =>
        {
            options.ConnectionString = "mongodb://localhost:27017";
            options.DatabaseName = "MyApp";
        })
        .AddWatchStream()  // Enable real-time change monitoring
        .RegisterDocumentsFromAssembly();
    });

3. Use the Document Monitor

public class UserService(IDocumentMonitor<User> monitor)
{
    // Create a new document
    public async Task<string> CreateUserAsync(User user)
    {
        return await monitor.Add(user);
    }

    // Get a document by ID
    public async Task<User> GetUserAsync(string id)
    {
        return await monitor.Get(id);
    }

    // Update a document (only changed fields are sent)
    public async Task UpdateUserAsync(User user)
    {
        user.Name = "New Name";  // Change is automatically tracked
        user.Email = "new@email.com";
        await monitor.SaveChanges(user);
    }

    // Lock a document for exclusive access
    public async Task<IDisposable> LockUserAsync(User user)
    {
        return await monitor.LockDocument(user);
    }
}

How It Works

Source Generation

When you decorate a class with [MongoObject], the source generator:

1. Validates the class structure at compile time
2. Generates partial property implementations with change tracking
3. Creates metadata query and record types
4. Generates type-safe search classes

Change Tracking

MongoObject uses INotifyPropertyChanged to track property changes:

var user = await monitor.Get(userId);
// user is now being tracked

user.Name = "Updated Name";  // Tracked: $set { "Document.Name": "Updated Name" }
user.Age = null;             // Tracked: $unset ["Document.Age"]

// Only changed fields are sent to MongoDB
await monitor.SaveChanges(user);

Document Structure

Documents are wrapped in MongoDocument<T>:

public class MongoDocument<T>
{
    public string Id { get; set; }           // MongoDB _id
    public T? Document { get; set; }         // Your business data
    public BsonDocument Metadata { get; set; } // Version, timestamps, etc.
}

Documentation

Full documentation is available at https://tenowg.github.io/MongoObject

Articles

• Getting Started
• Defining Documents
• Change Tracking
• Metadata
• Searching
• Projections
• Dependency Injection

Project Structure

MongoObject/
├── MongoObject.Core/              # Core library
│   ├── Attributes/                # [MongoObject], [ProjectValue]
│   ├── Data/                      # MongoDocument, TrackingObservableObject
│   ├── Interfaces/                # Core interfaces
│   ├── Services/                  # Service implementations
│   └── Extensions/                # DI extensions
├── MongoObject.SourceGenerator/   # Roslyn source generator
│   ├── Generators/                # CommonGenerator
│   └── Modules/                   # Generation modules
├── Docs/                          # Documentation (DocFX)
│   ├── articles/                  # Manual documentation
│   └── api/                       # API reference
└── Progress/                      # Demo/test project

Requirements

• .NET 10 SDK
• MongoDB 4.0+ (for change streams support)
• C# 14 (for partial properties)

Building from Source

# Debug build
dotnet build

# Release build (generates NuGet package)
dotnet build -c Release

# Run the demo project
dotnet run --project Progress

Roadmap

• Complete projection module implementation
• Add delete operations
• Implement polling-based watch mode
• Add batch operations support
• Comprehensive unit and integration tests
• Publish to NuGet

Contributing

Contributions are welcome! Please feel free to submit issues and pull requests.

License

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

Acknowledgments

• Built with MongoDB.Driver
• Uses Roslyn Source Generators
• Versioning with MinVer