Gener8 0.1.0

Gener8

A C# Roslyn source generator that copies public properties from a model class into a decorated partial DTO class at compile time — no reflection, no runtime overhead.

Installation

dotnet add package Gener8

The package is a development dependency — it is automatically marked PrivateAssets=all and adds no runtime reference to your project.

Quick start

// Your existing model
public class Product
{
    public required string Name { get; set; }
    public string Description { get; set; } = "";
    public decimal Price { get; set; }
    public bool InStock { get; set; }
}

// Your DTO — just add the attribute and make it partial
[FromModel(typeof(Product))]
internal partial class ProductDto { }

The generator emits at build time:

// <auto-generated/>
#nullable enable

internal partial class ProductDto
{
    public required string Name { get; set; }
    public string Description { get; set; } = "";
    public decimal Price { get; set; }
    public bool InStock { get; set; }
}

All accessor kinds (get, set, init), the required modifier, and property initializers are preserved exactly as declared on the source model.

Features

See docs/features.md for detailed examples of every feature.

Examples

Ignore properties

[FromModel(typeof(Product), Ignore = [nameof(Product.InternalCode)])]
internal partial class ProductDto { }

Type mapping

[FromModel(typeof(Order))]
[TypeMapping(typeof(Address), typeof(AddressDto))]
internal partial class OrderDto { }

Include inherited properties

[FromModel(typeof(DerivedProduct), IncludeInherited = true)]
internal partial class DerivedProductDto { }

Flatten a nested object

// Address { Street, City, PostCode }
[FromModel(typeof(Order), Flatten = [nameof(Order.ShippingAddress)])]
internal partial class OrderDto { }
// Emits: ShippingAddressStreet, ShippingAddressCity, ShippingAddressPostCode

Rename a property

[FromModel(typeof(Product))]
[RenameProperty(nameof(Product.InternalSku), "Sku")]
internal partial class ProductDto { }

Mapping extension methods

Every [FromModel] DTO automatically gets a companion extensions class with ToModel and ToDto methods:

[FromModel(typeof(Product))]
internal partial class ProductDto { }

// Generated automatically:
// internal static class ProductDtoExtensions
// {
//     public static Product    ToModel(this ProductDto dto)    { ... }
//     public static ProductDto ToDto  (this Product    model)  { ... }
// }

// Usage:
ProductDto dto = product.ToDto();
Product    model = dto.ToModel();

Type-mapped properties generate chained calls — dto.ShippingAddress.ToModel() and model.ShippingAddress.ToDto().

Repository scaffold

Set Repository to generate a concrete repository class that inherits from the SDK-specific abstract base provided by Gener8:

[FromModel(typeof(Product), Repository = RepositoryType.DynamoDb)]
internal partial class ProductDto { }

// Generates ProductDtoRepository.g.cs:
// internal partial class ProductDtoRepository : Gener8.DynamoDbRepository<Product, ProductDto>
// {
//     public ProductDtoRepository(IDynamoDbRepositoryContext context) : base(context) {}
//     protected override Product    ToModel(ProductDto dto)   => dto.ToModel();
//     protected override ProductDto ToDto  (Product    model) => model.ToDto();
// }

Use RepositoryType.MongoDb for a MongoDB variant — it receives an IMongoDbRepositoryContext and sets the collection name to the DTO class name automatically.

Use RepositoryType.Custom to get a partial scaffold backed by Gener8.RepositoryBase<TModel, TDto>. The constructor takes an IRepositoryContext (empty marker interface — wrap your own DB context). No CRUD methods are pre-generated; add them in a second partial class file. No extra NuGet package required.

DynamoDbRepository<TModel, TDto> implements ICompositeKeyRepository<TModel> (single- and composite-key CRUD). MongoDbRepository<TModel, TDto> implements IRepository<TModel>. All abstract bases are emitted only when at least one DTO requests them, so no SDK-type references leak into projects that do not use repositories.

The AWSSDK.DynamoDBv2 or MongoDB.Driver package must be referenced in the consuming project for DynamoDb/MongoDb respectively.

Documentation

Building from source

dotnet build src/Gener8/Gener8.csproj
dotnet test

License

MIT