BlogDoFT.Libs.EntityFramework.CodeGenerator 1.7.0

BlogDoFT.Libs.EntityFramework.CodeGenerator

A Roslyn Source Generator that reads filter DTOs annotated with BlogDoFT.Libs.EntityFramework.CodeGenerator.Abstractions.GeneratePredicateAttribute<TEntity> and emits:

• ToPredicate() → Expression<Func<TEntity, bool>>
• HasFilter() → bool

The generated predicates are provider-aware:

• On PostgreSQL (when Npgsql.EntityFrameworkCore.PostgreSQL is referenced), string filters with % use ILIKE.
• On other providers, string filters with % use EF.Functions.Like.
• No reflection is used; the generator detects NpgsqlDbFunctionsExtensions.ILike at compile-time.

Target Framework: netstandard2.0 (Analyzer-friendly)
C# Language Version: latest

Installation

Install the NuGet package:

dotnet add package BlogDoFT.Libs.EntityFramework.CodeGenerator.Generators

The application must also reference BlogDoFT.Libs.EntityFramework.CodeGenerator.Abstractions.

How it works

1. The generator scans the compilation for classes annotated with [GeneratePredicate<TEntity>];
2. It validates the DTO is partial; otherwise it reports PG001 (error).
3. It discovers filterable properties annotated with:
   • StringFilterAttribute
   • NumericFilterAttribute
   • TemporalFilterAttribute
   • BooleanFilterAttribute
4. It detects at compile-time whether NpgsqlDbFunctionsExtensions.ILike(DbFunctions, string, string) is available:
   • If present → emits code that builds expression calls to ILIKE
   • If absent → emits code that falls back to LIKE
5. It generates partial members HasFilter() and ToPredicate() into the same DTO namespace and type.

Example end-to-end

Entity

namespace Domain;

public class UserRecord
{
    public Guid Id { get; set; }
    public string Name { get; set; } = "";
    public string Email { get; set; } = "";
    public int Age { get; set; }
    public DateTime CreatedAt { get; set; }
    public bool Active { get; set; }
}

Filter DTO

using BlogDoFT.Libs.EntityFramework.CodeGenerator.Abstractions;

[GeneratePredicate<Domain.UserRecord>]
public partial class UserFilterDto
{
    [StringFilter(TargetProperty = nameof(Domain.UserRecord.Name), Order = 1)]
    public string? Name { get; init; }

    [StringFilter(TargetProperty = nameof(Domain.UserRecord.Email), Order = 2)]
    public string? Email { get; init; }

    [NumericFilter(TargetProperty = nameof(Domain.UserRecord.Age), Operator = ComparisonOperator.GreaterThanOrEqual)]
    public int? MinimumAge { get; init; }

    [TemporalFilter(TargetProperty = nameof(Domain.UserRecord.CreatedAt), Operator = ComparisonOperator.LessThanOrEqual)]
    public DateTime? CreatedUntil { get; init; }

    [BooleanFilter(TargetProperty = nameof(Domain.UserRecord.Active))]
    public bool? Active { get; init; }
}

Query with EF Core

var filter = new UserFilterDto
{
    Name = "%ann%",
    MinimumAge = 18,
    Active = true
};

var predicate = filter.ToPredicate();

var users = await db.Set<UserRecord>()
    .Where(predicate)
    .ToListAsync();

String pattern rules

• If the value does not contain %, the generator emits equality (field == value).
• If the value contains %, the generator emits a database pattern using:
  • ILIKE (PostgreSQL with Npgsql)
  • LIKE (fallback on other providers) This way you keep multi-database compatibility while getting case-insensitive matching on PostgreSQL.

If you want to support * as a wildcard in input, normalize it to % in your DTO before calling ToPredicate().

Requirements

• BlogDoFT.Libs.EntityFramework.CodeGenerator.Abstractions must be referenced by the app
• C# 11+ (generic attributes) in the app project
• EF Core 6/7/8+

Troubleshooting

The generated methods are missing

• Ensure the DTO is marked as partial;
• Ensure the app references BlogDoFT.Libs.EntityFramework.CodeGenerator.Abstractions and the generator as Analyzer.
• Clean and rebuild the solution.

I want to see SQL logs

Install and configure console logging:

<PackageReference Include="Microsoft.Extensions.Logging.Console" />

services.AddLogging(b =>
{
    b.ClearProviders();
    b.AddSimpleConsole();
    b.AddFilter("Microsoft.EntityFrameworkCore.Database.Command", LogLevel.Information);
});

Add in your DbContext Options:

options
    .UseLoggerFactory(loggerFactory)
    .EnableSensitiveDataLogging()
    .EnableDetailedErrors();