Stackworx.EfCoreGraphQL.DesignTime 0.0.3-alpha

Stackworx.EfCoreGraphQL.DesignTime

Generates HotChocolate DataLoaders and field extensions from your EF Core model whenever dotnet ef scaffolds a migration, by registering a custom IMigrationsCodeGenerator. Output is written next to the model snapshot as {ModelSnapshotName}.DataLoaders.g.cs.

1) Reference the package

Reference it from the project EF tooling loads design-time services from (commonly your startup project).

2) Register the generator

EF Core tooling discovers IDesignTimeServices automatically:

using Microsoft.EntityFrameworkCore.Design;
using Microsoft.Extensions.DependencyInjection;
using Stackworx.EfCoreGraphQL.DesignTime;

public sealed class DesignTimeServices : IDesignTimeServices
{
    public void ConfigureDesignTimeServices(IServiceCollection services)
        => services.AddEfCoreGraphQL();
}

3) Configure generation

AddEfCoreGraphQL takes a GenerateOptions, or an Action<GenerateOptions>:

using Stackworx.EfCoreGraphQL;
using Stackworx.EfCoreGraphQL.Abstractions;

public void ConfigureDesignTimeServices(IServiceCollection services)
    => services.AddEfCoreGraphQL(options =>
    {
        // Generate only for entities marked [EFCoreGraphQLInclude].
        options.Mode = Mode.OptIn;

        // Identity types are declared by the framework, so they cannot be annotated.
        options.Filter = EntityTypeFilters.AspNetIdentity;

        // Keep foreign-key scalars in an existing schema; clients may already select them.
        options.IgnoreForeignKeyFields = false;
    });

Registering the generator directly — services.AddSingleton<IMigrationsCodeGenerator, EfCoreMigrationsCodeGenerator>() — still works and uses the defaults above.

Adopting into an existing schema

Mode.OptIn with IgnoreForeignKeyFields = false adds nothing to the schema until you mark a type, and does not remove fields clients already select:

options.Mode = Mode.OptIn;
options.IgnoreForeignKeyFields = false;

[EFCoreGraphQLInclude]
public class Author { /* ... */ }

4) Set the output directory (required)

During scaffolding EF Core's working directory is often not the migrations project, so the output directory has to be explicit:

export STACKWORX_EFCOREGRAPHQL_SIDECAR_OUTPUT_DIR="/absolute/path/to/YourProject/Migrations"

$env:STACKWORX_EFCOREGRAPHQL_SIDECAR_OUTPUT_DIR = "C:\path\to\YourProject\Migrations"

It must point to an existing directory. Scaffolding fails with a clear error when it is unset or wrong.

5) Scaffold

dotnet ef migrations add InitialCreate \
  --project ./src/Your.Migrations.Project \
  --startup-project ./src/Your.Api.Project

The sidecar is rewritten on every snapshot generation, so changes that don't affect the snapshot text (e.g. adding [EFCoreGraphQLIgnore]) still take effect.