CODESAMPLE

Clean Architecture - Rust

Clean Architecture Rust

The Clean Architecture pattern separates the application into concentric layers: Entities, Use Cases, Interface Adapters, and Frameworks & Drivers. The core business logic resides in the inner layers (Entities & Use Cases) and is independent of external concerns like databases or UI. Outer layers implement interfaces defined by inner layers, controlling the flow of data to and from the core. This example demonstrates a simplified Clean Architecture with an entity, a use case, and a basic CLI interface adapter. Rust’s ownership and borrowing system aids in enforcing clear data flow boundaries, strong dependency inversion enabled through traits, and the compartmentalization central to this architecture.

// entities/user.rs
pub struct User {
    pub id: u32,
    pub name: String,
}

// use_cases/user_service.rs
pub trait UserRepository {
    fn get_user(&self, id: u32) -> Option<User>;
}

pub struct UserService<'a> {
    user_repository: &'a dyn UserRepository,
}

impl<'a> UserService<'a> {
    pub fn new(user_repository: &'a dyn UserRepository) -> Self {
        UserService { user_repository }
    }

    pub fn get_user_name(&self, id: u32) -> Option<String> {
        self.user_repository.get_user(id).map(|user| user.name)
    }
}

// interface_adapters/cli.rs
pub struct InMemoryUserRepository {
    users: Vec<User>,
}

impl InMemoryUserRepository {
    pub fn new(users: Vec<User>) -> Self {
        InMemoryUserRepository { users }
    }
}

impl UserRepository for InMemoryUserRepository {
    fn get_user(&self, id: u32) -> Option<User> {
        self.users.iter().find(|user| user.id == id).cloned()
    }
}

pub fn main() {
    let users = vec![
        User { id: 1, name: "Alice".to_string() },
        User { id: 2, name: "Bob".to_string() },
    ];
    let user_repository = InMemoryUserRepository::new(users);
    let user_service = UserService::new(&user_repository);

    if let Some(name) = user_service.get_user_name(1) {
        println!("User 1's name: {}", name);
    } else {
        println!("User 1 not found.");
    }
}