typed-uuid

Id is a typed wrapper around a uuid::Uuid.

Use it to add type safety and prevent confusion between different kinds of Uuid.

Example

Represent different types of Id to prevent mixups or invalid states. If describing a unique resource's relationship to another, for example the Role a User has, the relationship can be expressed as follows:

// Subtype the Id type to specify the version of the Id, instead
// of repeating yourself everywhere.
type Id<T> = typed_uuid::Id<T, typed_uuid::V4>;

struct Relation {
    user: Id<User>,
    role: Id<Role>,
}

Ids with different T parameter types are incompatible, and cannot be compared.

Attempting to assign an Id<User> to a variable of type Id<Role> is a compilation error.

let user = Id::<User>::new();
let role = Id::<Role>::new();

// Compilation fails here, can't compare Id<User> and Id<Role>
assert_eq!(user, role);

But Ids of the same type work:

let mut first = Id::<User>::new();
let second = Id::<User>::new();

first = second;
assert_eq!(first, second);

Usage

When depending on this library, you need to explicitly select the versions of the uuid, you will be using, as well as optionally serde support:

[dependencies.typed-uuid]
version = "*"
default-features = false
features = ["v4", "serde"]