# Core Query Cqrs Rs

> Criar queries CQRS Rust (leitura) na camada application. Usar quando o pedido envolver busca por id, listagem ou projeção read-only.

- Skill: `eskcti/core-query-cqrs-rs` (Agent Skill, multi-file: 2 files)
- Install (CLI): `npx skillmds@latest add eskcti/core-query-cqrs-rs`
- Raw SKILL.md: https://api.skillmd.com/api/skills/eskcti/core-query-cqrs-rs/raw
- Safety review: pending
- Works with: Claude Code, Claude.ai, OpenAI Codex
- Category: Coding & Dev Tools
- Author: EskCti (https://skillmd.com/u/eskcti)
- Updated: 2026-09-21
- Page: https://skillmd.com/skills/eskcti/core-query-cqrs-rs

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# Core Query CQRS (Rust)

## Overview

Queries em `application/find_<entity>_by_id.rs` ou `application/list_<bc>.rs` — struct implementando `UseCase<QueryInput, Output>` (não existe trait `Query` dedicado: queries e commands usam o mesmo `shared_kernel::UseCase`).

## Exemplo mínimo (query read-only)

```rust
use shared_kernel::{Result, UseCase};

use crate::modules::customers::application::CustomerOutput;
use crate::modules::customers::domain::ports::CustomerRepository;

pub struct FindCustomerById {
    pub repository: Arc<dyn CustomerRepository>,
}

impl UseCase<Uuid, Option<CustomerOutput>> for FindCustomerById {
    async fn execute(&self, id: Uuid) -> Result<Option<CustomerOutput>> {
        match self.repository.find_by_id(id).await? {
            None => Ok(None),
            Some(customer) => Ok(Some(CustomerOutput::from(&customer))),
        }
    }
}
```

## Guidelines

- Read-only; sem mutar aggregate.
- Pode retornar DTO diretamente (`CustomerOutput::from` — ver `core-dto-rs`).
- Mesmas regras de namespace que use cases: `modules::<bc>::application::<Name>`.

## Global Standards

- Consultar `../skills-standards.md` seção Rust.