# Rudi

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English | [简体中文](./README-zh_cn.md)

Rudi - an out-of-the-box dependency injection framework for Rust.

```rust
use rudi::{Context, Singleton, Transient};

// Register `fn(cx) -> A { A }` as the constructor for `A`
#[derive(Debug)]
#[Transient]
struct A;

#[derive(Debug)]
struct B(A);

// Register `fn(cx) -> B { B::new(cx.resolve::<A>()) }` as the constructor for `B`
#[Transient]
impl B {
    #[di]
    fn new(a: A) -> B {
        B(a)
    }
}

// Register `fn(cx) -> C { C::B(cx.resolve::<B>()) }` as the constructor for `C`
#[allow(dead_code)]
#[Transient]
enum C {
    A(A),

    #[di]
    B(B),
}

// Register `fn(cx) -> () { Run(cx.resolve::<B>(), cx.resolve::<C>()) }` as the constructor for `()`
#[Singleton]
fn Run(b: B, c: C) {
    println!("{:?}", b);
    assert!(matches!(c, C::B(_)));
}

fn main() {
    // Automatically register all types and functions with the `#[Singleton]`, `#[Transient]` or `#[SingleOwner]` attribute.
    let mut cx = Context::auto_register();

    // Get an instance of `()` from the `Context`, which will call the `Run` function.
    // This is equivalent to `cx.resolve::<()>();`
    cx.resolve()
}
```

## Features

- Three scopes: [`Singleton`](https://docs.rs/rudi/latest/rudi/enum.Scope.html#variant.Singleton), [`Transient`](https://docs.rs/rudi/latest/rudi/enum.Scope.html#variant.Transient) and [`SingleOwner`](https://docs.rs/rudi/latest/rudi/enum.Scope.html#variant.SingleOwner) ([example](./examples/all-scope/)).
- Async functions and async constructors.
- Attribute macros can be used on `struct`, `enum`, `impl block` and `function`.
- Manual and automatic registration (thanks to [inventory](https://github.com/dtolnay/inventory)).
- Easy binding of trait implementations and trait objects.
- Distinguishing different instances with types and names.
- Generics (but must be monomorphized and manually registered) ([example](./examples/hello-world-with-generic/)).
- Conditional registration ([example](./examples/condition/)).
- References (only `Singleton` and `SingleOwner` scope) ([example](./examples/reference/)).

## More complex example

```rust
use std::{fmt::Debug, rc::Rc};

use rudi::{Context, Singleton, Transient};

// Register `async fn(cx) -> i32 { 42 }` as the constructor for `i32`,
// and specify the name of the instance of this `i32` type as `"number"`.
#[Singleton(name = "number")]
async fn Number() -> i32 {
    42
}

// Register `async fn(cx) -> Foo { Foo { number: cx.resolve_with_name_async("number").await } }`
// as the constructor for `Foo`, and specify the name of the instance of this `Foo` type as `"foo"`.
#[derive(Debug, Clone)]
#[Singleton(async, name = "foo")]
struct Foo {
    #[di(name = "number")]
    number: i32,
}

#[derive(Debug)]
struct Bar(Foo);

impl Bar {
    fn into_debug(self) -> Rc<dyn Debug> {
        Rc::new(self)
    }
}

// Register `async fn(cx) -> Bar { Bar::new(cx.resolve_with_name_async("foo").await).await }`
// as the constructor for `Bar`.
//
// Bind the implementation of the `Debug` trait and the trait object of the `Debug` trait,
// it will register `asycn fn(cx) -> Rc<dyn Debug> { Bar::into_debug(cx.resolve_async().await) }`
// as the constructor for `Rc<dyn Debug>`.
#[Transient(binds = [Self::into_debug])]
impl Bar {
    #[di]
    async fn new(#[di(name = "foo")] f: Foo) -> Bar {
        Bar(f)
    }
}

#[Singleton]
async fn Run(bar: Bar, debug: Rc<dyn Debug>, #[di(name = "foo")] f: Foo) {
    println!("{:?}", bar);
    assert_eq!(format!("{:?}", bar), format!("{:?}", debug));
    assert_eq!(format!("{:?}", bar.0.number), format!("{:?}", f.number));
}

#[tokio::main]
async fn main() {
    let mut cx = Context::auto_register();

    cx.resolve_async().await
}
```

More examples can be found in the [examples](./examples/) and [tests](./rudi/tests/) directories.

## Credits

- [Koin](https://github.com/InsertKoinIO/koin): This project's API design and test cases were inspired by Koin.
- [inventory](https://github.com/dtolnay/inventory): This project uses inventory to implement automatic registration, making Rust's automatic registration very simple.

## Contributing

Thanks for your help improving the project! We are so happy to have you!

## License

Licensed under either of

- Apache License, Version 2.0,([LICENSE-APACHE](./LICENSE-APACHE) or <http://www.apache.org/licenses/LICENSE-2.0>)
- MIT license ([LICENSE-MIT](./LICENSE-MIT) or <http://opensource.org/licenses/MIT>)
  at your option.

### Contribution

Unless you explicitly state otherwise, any contribution intentionally submitted for inclusion in the work by you, as defined in the Apache-2.0 license, shall be dual licensed as above, without any additional terms or conditions.