Despro.Framework.Application 2.0.8

Despro.Framework.Application

The application (CQRS) layer of Despro Framework.

Despro.Framework.Application defines the CQRS contracts (commands, queries and their handlers) built on MediatR, plus the FluentValidation pipeline behavior that validates every command before it reaches a handler. This is the layer your use cases build directly on.

• Package: Despro.Framework.Application
• Version: 2.0.5
• Target framework: net10.0
• Depends on: Despro.Framework.Base, MediatR 14.0.0

Installation

dotnet add package Despro.Framework.Application

DI registration

using Despro.Framework.Application;

builder.Services.AddFrameworkApplication();

AddFrameworkApplication registers the CommandValidationBehavior<,> MediatR pipeline behavior and scans this assembly for FluentValidation validators. (The assemblies that contain your handlers/validators are registered separately by AddFrameworkInfrastructure.)

CQRS contracts (QueryCommandTools)

Commands — state-changing operations

Queries — read operations

Each query contract has a matching handler interface: IQueryHandler<,>, IQueryOperationHandler<,>, IQueryGridHandler<,>, IQueryGridOperationHandler<,>.

Validation pipeline

CommandValidationBehavior<TRequest, TResponse> runs all registered IValidator<TRequest> instances before the handler executes. If any rule fails it aggregates the messages and throws InvalidCommandException, short-circuiting the pipeline so handlers only ever run against valid input.

Exceptions (ApplicationExceptions)

• BaseApplicationException (abstract, extends Base's BaseException).
• InvalidCommandException — thrown by the validation behavior on validation failure.

Usage

// Command
public record CreateProductCommand(string Name, decimal Price) : ICommand<long>;

public class CreateProductCommandValidator : AbstractValidator<CreateProductCommand>
{
    public CreateProductCommandValidator()
    {
        RuleFor(x => x.Name).NotEmpty();
        RuleFor(x => x.Price).GreaterThan(0);
    }
}

public class CreateProductCommandHandler : ICommandHandler<CreateProductCommand, long>
{
    public async Task<OperationResult<long>> Handle(CreateProductCommand request, CancellationToken ct)
    {
        // ... persist and return
        return OperationResult<long>.Success(newId);
    }
}

// Grid query
public class ProductGridQuery(BaseGrid grid) : QueryGrid<ProductDto>(grid);

public class ProductGridQueryHandler : IQueryGridHandler<ProductGridQuery, ProductDto>
{
    public Task<GridData<ProductDto>> Handle(ProductGridQuery request, CancellationToken ct) { /* ... */ }
}

Dispatch through MediatR's ISender/IMediator; the validation behavior runs automatically.

Project structure

Despro.Framework.Application
├── ApplicationExceptions/   # BaseApplicationException, InvalidCommandException
├── QueryCommandTools/       # ICommand, IQuery, QueryGrid, CommandValidationBehavior
└── FrameworkApplicationDi.cs # AddFrameworkApplication