Branded

Branded types for Rust.

Branded types are types that have a unique brand attached to them. They are particularly useful for managing ID types in large domains where it is easy to confuse the IDs of different domain objects. With Rust's nominal typing, branded types makes it impossible to confuse the IDs.

Thanks to Rust's trait system, we can transparently derive traits for our branded types based on the inner type, making them completely transparent to other libraries such as serde, and sqlx.

This crate is a continuation of the now-archived bty crate. It has been rewritten to be a derive macro, and to support SQLx 0.8.

The crate provides the Branded trait and the Branded derive macro.

use branded::Branded;

#[derive(Branded)]
pub struct UserId(String);

Serde

The serde feature transparently derives the Serialize and Deserialize traits for the branded type. Pass serde as an option to the Branded derive macro to enable this feature.

use branded::Branded;

#[derive(Branded)]
#[branded(serde)]
pub struct UserId(String);

SQLx

The sqlx feature derives the Type, Encode, and Decode traits for the branded type. Pass sqlx as an option to the Branded derive macro to enable this feature.

use branded::Branded;

#[derive(Branded)]
#[branded(sqlx)]
pub struct UserId(String);

UUID

The uuid feature exposes nil() and new_v4() methods on the branded type. Pass uuid as an option to the Branded derive macro to enable this feature.

use branded::Branded;

#[derive(Branded)]
#[branded(uuid)]
pub struct UserId(uuid::Uuid);