commonsensesoftware / more-rs-di Goto Github PK

So on build_provider() it is possible to analyze and validate all registered services whether they are correct or not.

The build_provider() returns Result<ServiceProvider, Error>.

Validation rules on build_provider():

1. Singletons and Transient cannot be dependent on Scoped.
2. Dependency loop.
3. Service cannot be instantiated (no constructor or constructor contains unregistered types).
4. Ambiguous traits (has multiple implementations but required as single).
5. Ownership issues ???
6. ...

It is nice to see a simple di crate. I haven't seen other packages which have scoped descriptors implemented. 👍

It would be nice to have a feature when services are instantiated on demand, not immediately when parent service is being created.

For example:

pub struct MyService {
    sp: ServiceProvider,
    // s1: &Service1,
    // s2: &Service2,
}

impl MyService {
    fn new(sp: ServiceProvider) -> Self {
        Self { sp }
    }

    fn s1(&self) -> &Service1 {
        &self.sp.get_required::<Service1>();
    }

    fn s2(&self) -> &Service2 {
        &self.sp.get_required::<Service2>();
    }

   pub fn do_work_one(&self) {
      &self.s1.work_one();
   }

   pub fn do_work_two(&self) {
      &self.s2.work_two();
   }
}

and then somewhere else if we execute the following scope, only one service Service1 will be instantiated:

{
   var service = provider.get_required::<MyService>();
   service.do_work_one();
}

This is very useful when you have many heavy services and you don't want to instantiate them all. In other programming languages usually getter is used (eg. the property looks like this s1: Service1 { get { return &self.sp.get_required::<Service1>(); } }).

Note! Because of this approach it is hard to tell which services are dependent on MyService. But with some macros or just simply by scanning properties/methods and looking for their returning types I assume it is possible.

Trying to add service provider in salvo web framework and seems to fail.

let service_provider = ServiceCollection::default().build_provider();
let router = Router::new()
    .hoop(salvo::affix::inject(service_provider))

48 |         .hoop(salvo::affix::inject(service_provider))
   |               -------------------- ^^^^^^^^^^^^^^^^ `(dyn std::any::Any + 'static)` cannot be sent between threads safely
   |               |
   |               required by a bound introduced by this call

I do have async enabled.

more-di = { version = "1.0.0", features = ["async"] }