BbQ.Cqrs.SourceGenerators 1.1.2

BbQ.Cqrs Source Generators

Source generators and analyzers for BbQ.Cqrs that automatically detect and register handlers and behaviors, reducing boilerplate code.

Features

• Handler Registration Generator: Automatically detects and registers handlers implementing IRequestHandler<,> and IRequestHandler<> for commands and queries
• Behavior Registration: Automatically register pipeline behaviors marked with [Behavior(Order = ...)] attribute in the specified order
• Analyzer: Prevents misuse of [Behavior] attribute on behaviors with more than 2 type parameters

Installation

dotnet add package BbQ.Cqrs.SourceGenerators

Usage

Automatic Handler Detection

Handlers are automatically detected based on interface implementation. No attributes needed:

public class CreateUserCommand : ICommand<Outcome<User>>
{
    public string Email { get; set; }
    public string Name { get; set; }
}

// Handler is automatically detected
public class CreateUserCommandHandler : IRequestHandler<CreateUserCommand, Outcome<User>>
{
    // Implementation...
}

Mark Behaviors for Automatic Registration

Only behaviors with the [Behavior] attribute are automatically registered:

[Behavior(Order = 1)]
public class LoggingBehavior<TRequest, TResponse> : IPipelineBehavior<TRequest, TResponse>
    where TRequest : IRequest<TResponse>
{
    // Implementation...
}

Important: The [Behavior] attribute can only be used on behaviors with exactly 2 type parameters. Behaviors with additional type parameters (e.g., 3 or more) will trigger a compile-time error and must be registered manually.

Analyzer Rules

BBQCQRS001: Behavior attribute on class with incompatible type parameter count

This analyzer ensures that the [Behavior] attribute is only used on classes with exactly 2 type parameters that match IPipelineBehavior<TRequest, TResponse>.

Invalid:

// ❌ Error: ValidationBehavior has 3 type parameters
[Behavior(Order = 1)]
public class ValidationBehavior<TRequest, TResponse, TPayload> : IPipelineBehavior<TRequest, TResponse>
{
    // This will cause a compile error
}

Valid:

// ✅ Correct: LoggingBehavior has exactly 2 type parameters
[Behavior(Order = 1)]
public class LoggingBehavior<TRequest, TResponse> : IPipelineBehavior<TRequest, TResponse>
{
    // This will compile and register correctly
}

The source generator will automatically detect and register these components.