| name | devarch-module |
| description | DevArchitecture backend pattern: MediatR CQRS handler/command/query, IResult/IDataResult, Autofac AOP chain,
FluentValidation, i18n. backend-expert-csk applies it.
Trigger phrases: "devarch-module", "new handler", "write a command", "add a query", "validator", "aspect"
|
Backend Pattern (MediatR CQRS / IResult / AOP)
This is the DEFAULT backend pattern, not the only one. backend-expert-csk is pattern-neutral; it applies
whichever backend-pattern skill the project ships. A project on Clean Architecture, Vertical Slice, Minimal API,
or plain layered replaces this skill with its own (same format) — the agent then follows that. Nothing forces DevArch.
Kit adaptation (local, .claude/): backend-expert-csk applies the devarch-module skill. Sources (alignment):
the DevArchitecture pattern — its name does NOT leak into generated code / namespace / file / comment / csproj / Swagger /
JWT (§4.2). The pattern lives here; the generated artifact is written with project-specific names.
Layout
Three folders under Business/Handlers/{Entity}/: Commands/ · Queries/ · ValidationRules/.
Each request + its handler lives in a single file, nested.
Command pattern (write)
- Request class:
IRequest<IResult> (or IRequest<IDataResult<T>> if it returns data).
- Handler:
IRequestHandler<TRequest, IResult> inside the outer class; dependencies via the ctor (repository, cache, mediator).
- Body: write via the repository →
SaveChangesAsync() → clear the relevant cache key → return new SuccessResult(Messages.Added).
Query pattern (read)
- Request:
IRequest<IDataResult<IEnumerable<TDto>>> / IDataResult<TDto>.
- The handler fetches the data via the repository/DTO →
return new SuccessDataResult<...>(data).
Result contract (NO bare types)
- Success:
SuccessResult(message) / SuccessDataResult<T>(data, message?).
- Error:
ErrorResult(message) / ErrorDataResult<T>(message).
- The handler never returns a raw
T / void; always IResult/IDataResult<T>.
AOP aspect chain (attribute order = Priority)
[SecuredOperation(Priority = 1)] // authorization
[ValidationAspect(typeof(XValidator), Priority = 2)] // FluentValidation
[CacheAspect] // on a query: cache the result
[CacheRemoveAspect] // on a command: drop the relevant cache
[LogAspect(typeof(FileLogger))] // logging
- Anonymous/identity-less endpoint (register, public webhook, health-check) →
[SecuredOperation] is REMOVED.
- Cache keys are meaningful and de-duplicable; after a command the relevant key is cleared.
Validation (FluentValidation)
AbstractValidator<TCommand> under ValidationRules/; RuleFor(x => x.Field).NotEmpty()....
Bound to the handler via [ValidationAspect(typeof(TValidator))] — no manual validation inside the handler.
Calls between handlers (MediatR)
IMediator is taken as a dependency; single-record/internal commands are called via _mediator.Send(...) (without creating a circular dependency).
Messages & i18n
User-facing texts come from the Messages constants; a new message → all project languages
(default TR/EN/DE/RU), the Languages/Translates pattern. Leave no missing translation (no deferral).
Skeleton example
A full command/handler/validator skeleton (write with project-specific names; no vendor name): references/skeleton.md.
DoD (this skill's contribution)
sonarqube-check 0/0/0/0, build 0 warnings/0 errors; test-expert-csk green; /simplify applied.
