# Hexser - Zero-Boilerplate Hexagonal Architecture
[](https://crates.io/crates/hexser)
[](https://docs.rs/hexser)
[](https://github.com/squillo/hexser)
**Zero-boilerplate hexagonal architecture with graph-based introspection for Rust.**
The `hexser` crate provides reusable generic types and traits for implementing Hexagonal Architecture (Ports and Adapters pattern) with automatic graph construction, intent inference, and architectural validation. **Write business logic, let `hexser` handle the architecture.**
---
## 📚 Table of Contents
- [Why hexser?](#why-hexser)
- [Quick Start](#quick-start)
- [Complete Tutorial](#complete-tutorial)
- [CQRS Pattern with hex](#part-3-cqrs-pattern-with-hex)
- [Testing Your Hexagonal Application](#part-4-testing-your-hexagonal-application)
- [Error Handling](#part-5-error-handling)
- [Real-World Example - TODO Application](#part-6-real-world-example---todo-application)
- [Advanced Patterns](#advanced-patterns)
- [Knowledge Graph](#knowledge-graph)
- [Static (non-dyn) DI — WASM-friendly](#static-non-dyn-di--wasm-friendly)
- [Repository: Filter-based queries (vNext)](#repository-filter-based-queries-vnext)
- [AI Context Export (CLI)](#ai-context-export-cli)
- [Examples & Tutorials](#examples--tutorials)
- [Potions (copy-friendly examples)](#potions-copy-friendly-examples)
- [Contributing](#contributing)
- [License](#license)
- [Acknowledgments](#acknowledgments)
- [Additional Resources](#additional-resources)
> Tip: Press Cmd/Ctrl+F and search for “Part” to jump to tutorials.
## 🎯 Why hexser?
Traditional hexagonal architecture requires significant boilerplate:
- Manual registration of components
- Explicit dependency wiring
- Repetitive trait implementations
- Complex validation logic
**hexser eliminates all of this.** Through intelligent trait design, compile-time graph construction, and rich error handling, you get:
- [x] **Zero Boilerplate** - Define your types, derive traits, done
- [x] **Type-Safe Architecture** - Compiler enforces layer boundaries
- [x] **Self-Documenting** - Graph visualization shows your architecture
- [x] **Intent Inference** - System understands itself through structure
- [x] **Rich Errors** - Helpful, actionable error messages
- [x] **Zero Runtime Overhead** - Everything happens at compile time
- [x] **AI Completion** - Expose your Rust architecture to AI agents
---
## 🚀 Quick Start
Add to your `Cargo.toml`:
```toml
[dependencies]
hexser = "0.3.0"
```
Your First Hexagonal Application
```rust
use hexser::prelude::*;
// 1. Define your domain entity
#[derive(HexEntity)]
struct User {
id: String,
email: String,
name: String,
}
// 2. Define a port (interface)
#[derive(HexPort)]
trait UserRepository: Repository<User> {
fn find_by_email(&self, email: &str) -> HexResult<Option<User>>;
}
// 3. Implement an adapter
#[derive(HexAdapter)]
struct InMemoryUserRepository {
users: Vec<User>,
}
impl Repository<User> for InMemoryUserRepository {
fn find_by_id(&self, id: &String) -> HexResult<Option<User>> {
Ok(self.users.iter().find(|u| &u.id == id).cloned())
}
fn save(&mut self, user: User) -> HexResult<()> {
self.users.push(user);
Ok(())
}
fn delete(&mut self, id: &String) -> HexResult<()> {
self.users.retain(|u| &u.id != id);
Ok(())
}
fn find_all(&self) -> HexResult<Vec<User>> {
Ok(self.users.clone())
}
}
impl UserRepository for InMemoryUserRepository {
fn find_by_email(&self, email: &str) -> HexResult<Option<User>> {
Ok(self.users.iter().find(|u| u.email == email).cloned())
}
}
// 4. Use it!
fn main() -> HexResult<()> {
let mut repo = InMemoryUserRepository { users: Vec::new() };
let user = User {
id: "1".to_string(),
email: "alice@example.com".to_string(),
name: "Alice".to_string(),
};
repo.save(user)?;
let found = repo.find_by_email("alice@example.com")?;
println!("Found: {:?}", found.map(|u| u.name));
Ok(())
}
```
That's it! You've just built a hexagonal architecture application with:
- Clear layer separation
- Type-safe interfaces
- Testable components
- Swappable implementations
## 📚 Complete Tutorial
### Part 1: Understanding Hexagonal Architecture
Hexagonal Architecture (also known as Ports and Adapters) structures applications into concentric layers:
```
┌─────────────────────────────────────────────┐
│ Infrastructure Layer │
│ (Databases, APIs, External Services) │
│ │
│ ┌───────────────────────────────────────┐ │
│ │ Adapters Layer │ │
│ │ (Concrete Implementations) │ │
│ │ │ │
│ │ ┌─────────────────────────────────┐ │ │
│ │ │ Ports Layer │ │ │
│ │ │ (Interfaces/Contracts) │ │ │
│ │ │ │ │ │
│ │ │ ┌───────────────────────────┐ │ │ │
│ │ │ │ Domain Layer │ │ │ │
│ │ │ │ (Business Logic) │ │ │ │
│ │ │ └───────────────────────────┘ │ │ │
│ │ └─────────────────────────────────┘ │ │
│ └───────────────────────────────────────┘ │
└─────────────────────────────────────────────┘
```
**Key Principles:**
- Dependency Rule: Dependencies point inward (Domain has no dependencies)
- Port Interfaces: Define what the domain needs (don't dictate how)
- Adapter Implementations: Provide concrete implementations using specific tech
- Testability: Mock adapters for testing without infrastructure
### Part 2: The Five Layers
1. Domain Layer - Your Business Logic
The domain layer contains your core business logic, completely independent of frameworks or infrastructure.
Entities - Things with identity:
```rust
use hexser::prelude::*;
#[derive(HexEntity)]
struct Order {
id: OrderId,
customer_id: CustomerId,
items: Vec<OrderItem>,
status: OrderStatus,
}
impl Aggregate for Order {
fn check_invariants(&self) -> HexResult<()> {
if self.items.is_empty() {
return Err(hexser::hex_domain_error!(
hexser::error::codes::domain::INVARIANT_EMPTY,
"Order must contain at least one item"
).with_next_step("Add at least one item"));
}
Ok(())
}
}
```
Value Objects - Things defined by values:
```rust
#[derive(Clone, PartialEq, Eq, HexValueObject)]
struct Email(String);
impl Email {
fn validate(&self) -> HexResult<()> {
if !self.0.contains('@') {
return Err(Hexserror::validation("Email must contain @"));
}
Ok(())
}
}
```
Domain Events - Things that happened:
```rust
#[derive(HexDomainEvent)]
struct OrderPlaced {
order_id: OrderId,
customer_id: CustomerId,
timestamp: u64,
}
```
Domain Services - Operations spanning multiple entities:
```rust
#[derive(HexDomainService)]
struct PricingService;
impl PricingService {
fn calculate_order_total(&self, order: &Order) -> Money {
order.items
.iter()
.map(|item| item.price * item.quantity)
.sum()
}
}
```
2. Ports Layer - Your Interfaces
Ports define the contracts between your domain and the outside world.
Repositories - Persistence abstraction:
```rust
#[derive(HexPort)]
trait OrderRepository: Repository<Order> {
fn find_by_customer(&self, customer_id: &CustomerId)
-> HexResult<Vec<Order>>;
fn find_pending(&self) -> HexResult<Vec<Order>>;
}
```
Use Cases - Business operations:
```rust
#[derive(HexPort)]
trait PlaceOrder: UseCase<PlaceOrderInput, PlaceOrderOutput> {}
struct PlaceOrderInput {
customer_id: CustomerId,
items: Vec<OrderItem>,
}
struct PlaceOrderOutput {
order_id: OrderId,
}
```
Queries - Read operations (CQRS):
```rust
#[derive(HexPort)]
trait OrderHistory: Query<OrderHistoryParams, Vec<OrderView>> {}
struct OrderHistoryParams {
customer_id: CustomerId,
from_date: u64,
to_date: u64,
}
struct OrderView {
order_id: String,
total: f64,
status: String,
}
```
3. Adapters Layer - Your Implementations
Adapters implement ports using specific technologies.
Database Adapter:
```rust
#[derive(HexAdapter)]
struct PostgresOrderRepository {
pool: PgPool,
}
impl Repository<Order> for PostgresOrderRepository {
fn find_by_id(&self, id: &OrderId) -> HexResult<Option<Order>> {
// SQL query implementation
todo!()
}
fn save(&mut self, order: Order) -> HexResult<()> {
// SQL insert/update implementation
todo!()
}
// ... other methods
}
impl OrderRepository for PostgresOrderRepository {
fn find_by_customer(&self, customer_id: &CustomerId)
-> HexResult<Vec<Order>> {
// Custom query implementation
todo!()
}
fn find_pending(&self) -> HexResult<Vec<Order>> {
// Custom query implementation
todo!()
}
}
```
API Adapter:
```rust
#[derive(HexAdapter)]
struct RestPaymentGateway {
client: reqwest::Client,
api_key: String,
}
impl PaymentPort for RestPaymentGateway {
fn charge(&self, amount: Money, card: &Card) -> HexResult<PaymentResult> {
// HTTP API call implementation
todo!()
}
}
```
Mapper - Data transformation:
```rust
#[derive(HexAdapter)]
struct OrderMapper;
impl Mapper<Order, DbOrderRow> for OrderMapper {
fn map(&self, order: Order) -> HexResult<DbOrderRow> {
Ok(DbOrderRow {
id: order.id.to_string(),
customer_id: order.customer_id.to_string(),
items_json: serde_json::to_string(&order.items)?,
status: order.status.to_string(),
})
}
}
```
4. Application Layer - Your Orchestration
The application layer coordinates domain logic and ports.
Directive (Write Operation):
```rust
#[derive(HexDirective)]
struct PlaceOrderDirective {
customer_id: CustomerId,
items: Vec<OrderItem>,
}
impl PlaceOrderDirective {
fn validate(&self) -> HexResult<()> {
if self.items.is_empty() {
return Err(Hexserror::validation("Items cannot be empty"));
}
Ok(())
}
}
```
Directive Handler:
```rust
#[derive(HexDirectiveHandler)]
struct PlaceOrderHandler {
order_repo: Box<dyn OrderRepository>,
payment_port: Box<dyn PaymentPort>,
}
impl PlaceOrderHandler {
fn handle(&self, directive: PlaceOrderDirective) -> HexResult<()> {
// Validate
directive.validate()?;
// Create domain object
let order = Order::new(directive.customer_id, directive.items)?;
// Check invariants
order.check_invariants()?;
// Save
self.order_repo.save(order)?;
// Side effects
self.payment_port.charge(order.total(), &order.payment_method)?;
Ok(())
}
}
```
Query Handler:
```rust
#[derive(HexQueryHandler)]
struct OrderHistoryHandler {
query_repo: Box<dyn OrderQueryRepository>,
}
impl OrderHistoryHandler {
fn handle(&self, params: OrderHistoryParams) -> HexResult<Vec<OrderView>> {
self.query_repo.get_order_history(
¶ms.customer_id,
params.from_date,
params.to_date
)
}
}
```
5. Infrastructure Layer - Your Technology
Infrastructure provides the concrete technology implementations.
```rust
#[derive(HexConfig)]
struct DatabaseConfig {
connection_string: String,
pool_size: u32,
}
impl DatabaseConfig {
fn create_pool(&self) -> PgPool {
todo!()
}
}
```
### Part 3: CQRS Pattern with hex
hexser supports Command Query Responsibility Segregation (CQRS) out of the box.
Write Side (Directives):
```rust
// Directive represents intent to change state
#[derive(HexDirective)]
struct UpdateUserEmail {
user_id: UserId,
new_email: Email,
}
impl UpdateUserEmail {
fn validate(&self) -> HexResult<()> {
self.new_email.validate()
}
}
// Handler executes the directive
#[derive(HexDirectiveHandler)]
struct UpdateUserEmailHandler {
repo: Box<dyn UserRepository>,
}
impl UpdateUserEmailHandler {
fn handle(&self, directive: UpdateUserEmail) -> HexResult<()> {
let mut user = self.repo.find_by_id(&directive.user_id)?
.ok_or_else(|| Hexserror::not_found("User", &directive.user_id))?;
user.email = directive.new_email;
self.repo.save(user)?;
Ok(())
}
}
```
Read Side (Queries):
```rust
// Query represents read operation
#[derive(HexQuery)]
struct FindUserByEmail {
email: String,
}
// Handler executes the query
#[derive(HexQueryHandler)]
struct FindUserByEmailHandler {
query_repo: Box<dyn UserQueryRepository>,
}
impl FindUserByEmailHandler {
fn handle(&self, query: FindUserByEmail)
-> HexResult<Option<UserView>> {
self.query_repo.find_by_email(&query.email)
}
}
```
### Part 4: Testing Your Hexagonal Application
Hexagonal architecture makes testing trivial - just mock the ports!
Unit Testing Domain Logic:
```rust
#[cfg(test)]
mod tests {
use super::*;
#[test]
fn test_order_invariants() {
let order = Order {
id: OrderId::new(),
customer_id: CustomerId::new(),
items: vec![], // Empty!
status: OrderStatus::Pending,
};
assert!(order.check_invariants().is_err());
}
#[test]
fn test_email_validation() {
let invalid = Email("notanemail".to_string());
assert!(invalid.validate().is_err());
let valid = Email("test@example.com".to_string());
assert!(valid.validate().is_ok());
}
}
```
Testing with Mock Adapters:
```rust
#[derive(HexAdapter)]
struct MockUserRepository {
users: std::collections::HashMap<UserId, User>,
}
impl Repository<User> for MockUserRepository {
fn find_by_id(&self, id: &UserId) -> HexResult<Option<User>> {
Ok(self.users.get(id).cloned())
}
fn save(&mut self, user: User) -> HexResult<()> {
self.users.insert(user.id.clone(), user);
Ok(())
}
// ... other methods
}
#[test]
fn test_create_user_handler() {
let mut repo = MockUserRepository {
users: std::collections::HashMap::new(),
};
let handler = CreateUserHandler {
repo: Box::new(repo),
};
let directive = CreateUserDirective {
email: "test@example.com".to_string(),
name: "Test User".to_string(),
};
assert!(handler.handle(directive).is_ok());
}
```
### Part 5: Error Handling
hexser provides rich, actionable, code-first errors with automatic source location and layering support. Prefer the new macro-based constructors and error codes over manual struct construction.
Preferred: macro + code + guidance
```rust
fn validate_order(order: &Order) -> HexResult<()> {
if order.items.is_empty() {
return Err(
hexser::hex_domain_error!(
hexser::error::codes::domain::INVARIANT_EMPTY,
"Order must contain at least one item"
)
.with_next_steps(&["Add at least one item to the order"]) // actionable guidance
.with_suggestions(&["order.add_item(item)", "order.items.push(item)"]) // quick fixes
.with_more_info("https://docs.rs/hexser/latest/hexser/error/codes/domain")
);
}
Ok(())
}
```
Display output (example):
```
E_HEX_001: Order must contain at least one item
at src/domain/order.rs:42:13
Next steps:
- Add at least one item to the order
Suggestions:
- order.add_item(item)
- order.items.push(item)
```
Cookbook
```rust,ignore
// Validation errors (field-aware)
return Err(hexser::error::hex_error::Hexserror::validation_field(
"Title cannot be empty",
"title",
));
// Not Found errors (resource + id)
return Err(hexser::error::hex_error::Hexserror::not_found("User", "123")
.with_next_step("Verify the ID and try again"));
// Port errors (communication issues)
let port_err = hexser::hex_port_error!(
hexser::error::codes::port::PORT_TIMEOUT,
"User service timed out"
).with_suggestion("Increase timeout or retry later");
// Adapter errors (infra failures) with source error
fn fetch_from_api(url: &str) -> HexResult<String> {
let resp = std::fs::read_to_string(url)
.map_err(|ioe| hexser::hex_adapter_error!(
hexser::error::codes::adapter::IO_FAILURE, // or API_FAILURE in real HTTP
"Failed to fetch resource"
).with_source(ioe))?;
Ok(resp)
}
```
🔥 Amazing Example: Layered mapping (Adapter → Port → Domain)
```rust
// Adapter layer
fn db_get_user(id: &str) -> HexResult<User> {
let conn = std::fs::read_to_string("/tmp/mock-db").map_err(|e|
hexser::hex_adapter_error!(
hexser::error::codes::adapter::DB_CONNECTION_FAILURE,
"Database unavailable"
)
.with_source(e)
.with_next_steps(&["Ensure DB is running", "Check connection string"])
)?;
// ... parse and return User or NotFound
Err(hexser::error::hex_error::Hexserror::not_found("User", id))
}
// Port layer wraps adapter failure with port context
fn port_get_user(id: &str) -> HexResult<User> {
db_get_user(id).map_err(|e|
hexser::hex_port_error!(
hexser::error::codes::port::COMMUNICATION_FAILURE,
"UserRepository failed"
).with_source(e)
)
}
// Domain layer consumes rich errors
fn ensure_user_exists(id: &str) -> HexResult<()> {
let _user = port_get_user(id)?; // `?` preserves full rich error stack
Ok(())
}
```
Notes
- All hexser errors implement std::error::Error and the RichError trait (code, message, next_steps, suggestions, location, more_info, source).
- Prefer hex_domain_error!, hex_port_error!, hex_adapter_error! and constants from hexser::error::codes::*.
- Use with_source(err) to preserve underlying causes; Display shows a helpful, compact summary.
Part 6: Real-World Example - TODO Application
Let's build a complete TODO application using hexagonal architecture.
Domain Layer:
```rust
use hexser::prelude::*;
#[derive(Clone, HexEntity)]
struct Todo {
id: TodoId,
title: String,
description: String,
completed: bool,
}
#[derive(Clone, PartialEq, Eq, Hash)]
struct TodoId(String);
impl TodoId {
fn new() -> Self {
Self(uuid::Uuid::new_v4().to_string())
}
}
```
Ports Layer:
```rust
#[derive(HexPort)]
trait TodoRepository: Repository<Todo> {
fn find_active(&self) -> HexResult<Vec<Todo>>;
fn find_completed(&self) -> HexResult<Vec<Todo>>;
}
```
Adapters Layer:
```rust
#[derive(HexAdapter)]
struct InMemoryTodoRepository {
todos: std::sync::Mutex<Vec<Todo>>,
}
impl Repository<Todo> for InMemoryTodoRepository {
fn find_by_id(&self, id: &TodoId) -> HexResult<Option<Todo>> {
let todos = self.todos.lock().unwrap();
Ok(todos.iter().find(|t| &t.id == id).cloned())
}
fn save(&mut self, todo: Todo) -> HexResult<()> {
let mut todos = self.todos.lock().unwrap();
if let Some(existing) = todos.iter_mut().find(|t| t.id == todo.id) {
*existing = todo;
} else {
todos.push(todo);
}
Ok(())
}
fn delete(&mut self, id: &TodoId) -> HexResult<()> {
let mut todos = self.todos.lock().unwrap();
todos.retain(|t| &t.id != id);
Ok(())
}
fn find_all(&self) -> HexResult<Vec<Todo>> {
let todos = self.todos.lock().unwrap();
Ok(todos.clone())
}
}
impl TodoRepository for InMemoryTodoRepository {
fn find_active(&self) -> HexResult<Vec<Todo>> {
let todos = self.todos.lock().unwrap();
Ok(todos.iter().filter(|t| !t.completed).cloned().collect())
}
fn find_completed(&self) -> HexResult<Vec<Todo>> {
let todos = self.todos.lock().unwrap();
Ok(todos.iter().filter(|t| t.completed).cloned().collect())
}
}
```
Application Layer:
```rust
#[derive(HexDirective)]
struct CreateTodoDirective {
title: String,
description: String,
}
impl CreateTodoDirective {
fn validate(&self) -> HexResult<()> {
if self.title.is_empty() {
return Err(Hexserror::validation_field("Title cannot be empty", "title"));
}
Ok(())
}
}
#[derive(HexDirectiveHandler)]
struct CreateTodoHandler {
repo: Box<dyn TodoRepository>,
}
impl CreateTodoHandler {
fn handle(&self, directive: CreateTodoDirective) -> HexResult<()> {
directive.validate()?;
let todo = Todo {
id: TodoId::new(),
title: directive.title,
description: directive.description,
completed: false,
};
self.repo.save(todo)?;
Ok(())
}
}
```
---
## 🎓 Advanced Patterns
Event Sourcing
```rust
#[derive(HexAggregate)]
struct OrderAggregate {
id: OrderId,
uncommitted_events: Vec<Box<dyn DomainEvent>>,
}
impl OrderAggregate {
fn place_order(&mut self, items: Vec<OrderItem>) -> HexResult<()> {
// Validate
if items.is_empty() {
return Err(hexser::hex_domain_error!(
hexser::error::codes::domain::INVARIANT_EMPTY,
"Order must have items"
));
}
// Create event
let event = OrderPlaced {
order_id: self.id.clone(),
items,
timestamp: current_timestamp(),
};
// Apply event
self.apply_event(&event);
// Record event
self.uncommitted_events.push(Box::new(event));
Ok(())
}
fn apply_event(&mut self, event: &dyn DomainEvent) {
// Update state based on event
}
}
```
Dependency Injection
```rust
struct ApplicationContext {
user_repo: Box<dyn UserRepository>,
order_repo: Box<dyn OrderRepository>,
payment_port: Box<dyn PaymentPort>,
}
impl ApplicationContext {
fn new_production() -> Self {
Self {
user_repo: Box::new(PostgresUserRepository::new()),
order_repo: Box::new(PostgresOrderRepository::new()),
payment_port: Box::new(StripePaymentGateway::new()),
}
}
fn new_test() -> Self {
Self {
user_repo: Box::new(MockUserRepository::new()),
order_repo: Box::new(MockOrderRepository::new()),
payment_port: Box::new(MockPaymentGateway::new()),
}
}
}
```
## 📊 Knowledge Graph
```
hexser/
├── domain/ [Core Business Logic - No Dependencies]
│ ├── Entity - Identity-based objects
│ ├── ValueObject - Value-based objects
│ ├── Aggregate - Consistency boundaries
│ ├── DomainEvent - Significant occurrences
│ └── DomainService - Cross-entity operations
│
├── ports/ [Interface Definitions]
│ ├── Repository - Persistence abstraction
│ ├── UseCase - Business operations
│ ├── Query - Read-only operations (CQRS)
│ ├── InputPort - Entry points
│ └── OutputPort - External system interfaces
│
├── adapters/ [Concrete Implementations]
│ ├── Adapter - Port implementations
│ └── Mapper - Data transformation
│
├── application/ [Orchestration Layer]
│ ├── Directive - Write operations (CQRS)
│ ├── DirectiveHandler - Directive execution
│ └── QueryHandler - Query execution
│
├── infrastructure/ [Technology Layer]
│ └── Config - Infrastructure setup
│
├── error/ [Rich Error Types]
│ └── Hexserror - Actionable errors
│
└── graph/ [Introspection - Phase 2+]
├── Layer - Architectural layers
├── Role - Component roles
├── Relationship - Component connections
└── NodeId - Unique identification
```
## 💡 Design Philosophy
- "Language of the Language": Use Rust's type system to express architecture
- Zero Boilerplate: Derive everything, configure nothing
- Compile-Time Guarantees: Catch errors before runtime
- Rich Errors: Every error is helpful and actionable
- Self-Documenting: Graph reveals architecture automatically
- Testability First: Mock anything, test everything
## 🤝 Contributing
We welcome contributions! This crate follows strict coding standards:
- One item per file: Each file contains one logical item
- No imports: Fully qualified paths (except std prelude)
- Documentation: Every item has //! and /// docs
- In-file tests: Tests live with the code they test
- No unsafe: Safe Rust only
- Rust 2024: Latest edition
See CONTRIBUTING.md for details.
## 📄 License
Licensed under either of:
- Apache License, Version 2.0 (LICENSE-APACHE)
- MIT license (LICENSE-MIT)
at your option.
## 🙏 Acknowledgments
Inspired by:
- CEQRS by Scott Wyatt
- N Lang by Scott Wyatt
- Domain-Driven Design by Eric Evans
- Hexagonal Architecture by Alistair Cockburn
- Clean Architecture by Robert C. Martin
- Rust's type system and error handling
- The Rust community's commitment to excellence
## 📚 Additional Resources
- Hexagonal Architecture Explained
- Domain-Driven Design
- CQRS Pattern
- Ports and Adapters
## 🎯 Examples & Tutorials
The hex crate includes comprehensive examples and tutorials to help you learn hexagonal architecture.
Running Examples
```bash
cargo run --example simple_todo
```
---
## 🧪 Potions (copy-friendly examples)
Looking for concrete, minimal examples you can paste into your app?
Check out the Potions crate in this workspace:
- Path: ./hexser_potions
- Crate: hexser_potions
- Focus: small, mixable examples (auth signup, CRUD, etc.)
Add to your project via workspace path:
```toml
[dependencies]
hexser_potions = { path = "../hexser_potions", version = "0.3.0" }
```
Then in code:
```rust
use hexser_potions::auth::{SignUpUser, InMemoryUserRepository, execute_signup};
```
---
## ⚙️ Static (non-dyn) DI — WASM-friendly
When you want zero dynamic dispatch and the smallest possible runtime footprint (including on wasm32-unknown-unknown), use the new static DI utilities.
Feature flags:
- Enabled by default: `static-di`
- Opt-in for dyn container (tokio-based): `container`
Static DI provides two simple building blocks:
- `StaticContainer<T>`: owns your fully built object graph
- `hex_static! { ... }` macro: builds the graph from a block without any `dyn`
Example:
```rust,ignore
use hexser::prelude::*;
#[derive(Clone, Debug)]
struct Repo;
#[derive(Clone, Debug)]
struct Service { repo: Repo }
let app = hexser::hex_static!({
let repo = Repo;
let service = Service { repo: repo.clone() };
(repo, service)
});
let (repo, service) = app.into_inner();
```
WASM guidance:
- Default features are WASM-friendly (no tokio). Keep `container` disabled for wasm.
- Use `static-di` (default) and avoid the dyn container for maximum compatibility.
---
## Repository: Filter-based queries (vNext)
We are migrating the repository port away from id-centric methods (find_by_id/find_all) toward a generic, filter-oriented API that better models your domain while staying storage-agnostic. The new QueryRepository trait introduces domain-owned Filter and SortKey types plus FindOptions for sorting and pagination.
Highlights:
- Define small Filter and SortKey enums/structs in your domain
- Use find_one for unique lookups and find for lists with sorting/pagination
- Legacy methods are still available but deprecated; prefer the new API
Example:
```rust
use hexser::prelude::*;
use hexser::ports::repository::{QueryRepository, FindOptions, Sort, Direction};
#[derive(HexEntity, Clone, Debug)]
struct User { id: String, email: String, created_at: u64 }
// Domain-owned query types
#[derive(Clone, Debug)]
enum UserFilter {
ById(String),
ByEmail(String),
All,
}
#[derive(Clone, Copy, Debug, PartialEq, Eq)]
enum UserSortKey { CreatedAt, Email }
#[derive(Default)]
struct InMemoryUserRepository { users: Vec<User> }
impl Repository<User> for InMemoryUserRepository {
fn find_by_id(&self, id: &String) -> HexResult<Option<User>> { Ok(self.users.iter().find(|u| &u.id == id).cloned()) }
fn save(&mut self, user: User) -> HexResult<()> { if let Some(i)=self.users.iter().position(|u| u.id==user.id){self.users[i]=user;} else { self.users.push(user);} Ok(()) }
fn delete(&mut self, id: &String) -> HexResult<()> { self.users.retain(|u| &u.id != id); Ok(()) }
fn find_all(&self) -> HexResult<Vec<User>> { Ok(self.users.clone()) }
}
impl QueryRepository<User> for InMemoryUserRepository {
type Filter = UserFilter;
type SortKey = UserSortKey;
fn find_one(&self, f: &Self::Filter) -> HexResult<Option<User>> {
Ok(self.users.iter().find(|u| match f { UserFilter::ById(id)=>&u.id==id, UserFilter::ByEmail(e)=>&u.email==e, UserFilter::All=>true }).cloned())
}
fn find(&self, f: &Self::Filter, opts: FindOptions<Self::SortKey>) -> HexResult<Vec<User>> {
let mut items: Vec<_> = self.users.iter().filter(|u| match f { UserFilter::ById(id)=>&u.id==id, UserFilter::ByEmail(e)=>&u.email==e, UserFilter::All=>true }).cloned().collect();
if let Some(sorts) = opts.sort {
for s in sorts.into_iter().rev() {
match (s.key, s.direction) {
(UserSortKey::CreatedAt, Direction::Asc) => items.sort_by_key(|u| u.created_at),
(UserSortKey::CreatedAt, Direction::Desc) => items.sort_by_key(|u| std::cmp::Reverse(u.created_at)),
(UserSortKey::Email, Direction::Asc) => items.sort_by(|a,b| a.email.cmp(&b.email)),
(UserSortKey::Email, Direction::Desc) => items.sort_by(|a,b| b.email.cmp(&a.email)),
}
}
}
let offset = opts.offset.unwrap_or(0) as usize;
let limit = opts.limit.map(|l| l as usize).unwrap_or_else(|| items.len().saturating_sub(offset));
let end = offset.saturating_add(limit).min(items.len());
Ok(items.into_iter().skip(offset).take(end.saturating_sub(offset)).collect())
}
}
fn main() -> HexResult<()> {
let repo = InMemoryUserRepository::default();
// Unique lookup
let _ = <InMemoryUserRepository as QueryRepository<User>>::find_one(&repo, &UserFilter::ByEmail("alice@ex.com".into()))?;
// List with pagination
let opts = FindOptions { sort: Some(vec![Sort { key: UserSortKey::CreatedAt, direction: Direction::Desc }]), limit: Some(25), offset: Some(0) };
let _page = <InMemoryUserRepository as QueryRepository<User>>::find(&repo, &UserFilter::All, opts)?;
Ok(())
}
```
Migration tips:
- find_by_id(id) -> find_one(&Filter::ById(id))
- find_all() -> find(&Filter::All, FindOptions::default())
- Add sorting/pagination via FindOptions { sort, limit, offset }
For more details, see MIGRATION_GUIDE.md and docs/core-concepts.md.
---
## 🤖 AI Context Export (CLI)
Export a machine-readable JSON describing your project's architecture for AI assistants and tooling.
Requirements:
- Enable the `ai` feature (serde/serde_json are included automatically).
Commands:
```sh
# Build and run the exporter (prints JSON to stdout)
cargo run -p hexser --features ai --bin hex-ai-export
# Save to a file
cargo run -p hexser --features ai --bin hex-ai-export --quiet > target/ai-context.json
```
What it does:
- Builds the current `HexGraph` from the component registry
- Generates an `AIContext` via `hexser::ai::ContextBuilder`
- Serializes to JSON with a stable field order
Notes:
- The binary `hex-ai-export` is only built when the `ai` feature is enabled.
- For reproducible diffs, commit `target/ai-context.json` or generate it in CI as an artifact.
### 🧠 AI Agent Pack (All-in-One)
Export a comprehensive, single-file JSON that bundles:
- AIContext (machine-readable architecture)
- Guidelines snapshot (rules enforced for agents)
- Embedded key docs (README, ERROR_GUIDE, and local AI/guideline prompts when present)
Commands:
```sh
# Print Agent Pack JSON to stdout
cargo run -p hexser --features ai --bin hex-ai-pack
# Save to a file
cargo run -p hexser --features ai --bin hex-ai-pack --quiet > target/ai-pack.json
```
Notes:
- Missing optional docs are skipped gracefully. The pack remains valid JSON.
- Use this artifact as the single source of truth for external AIs and tools when proposing changes.