API Resources

API Resources (DTOs - Data Transfer Objects) are used to define the shape of data exchanged between the API and clients. They separate internal database models from external API contracts.

DTO Pattern

// API Response DTO
#[derive(Debug, Serialize, Deserialize, Clone)]
pub struct UserResponse {
    pub id: String,      // Serialized as string for JS precision
    pub username: String,
    pub dept_name: Option<String>,
    pub created_at: String,
}

// API Request DTO
#[derive(Debug, Deserialize, Validate)]
pub struct CreateUserRequest {
    #[validate(length(min = 2, max = 50))]
    pub username: String,
    #[validate(email)]
    pub email: String,
    #[validate(length(min = 6))]
    pub password: String,
}

// Conversion from Model to DTO
impl From<entity::sys_user::Model> for UserResponse {
    fn from(model: entity::sys_user::Model) -> Self {
        Self {
            id: model.id.to_string(),  // Convert i64 to string
            username: model.username,
            dept_name: None,
            created_at: model.created_at.format("%Y-%m-%d %H:%M:%S").to_string(),
        }
    }
}

Best Practices

• Avoid exposing database models directly in API responses
• Use DTOs to control the shape and format of API data
• Handle i64→String conversion for JavaScript compatibility
• Use validation annotations on request DTOs