Routing Scope vs Resources

[felipero]

Hi guys, congrats on the framework. It is nice and fun to play with.

I have a question about the routing, that is not clear in the documentation. What's the practical difference between Scope and Resource in the routing. Why I can add services to a Scope but not to a Resource? I know a resource is registered into the ResourceMap, but looks like the Scope is too. So, I'm not sure what the real differences are, and I think that should be written in to the documentation. I'd be happy to send a PR if I figure this out.

[fakeshadow]

Scope has a private Router type which can route incoming request to it's children services.
Resource does not know anything about routing.

[fakeshadow]

Don't take the naming too literal.
Resource only match on Guard trait object and return the first one that does not conflict with the guards.

Or to be specific. Route is a type of serivce that has associate guards like methods and headers. The routing part is done elsewhere

[felipero]

I was under the impression the Resource was routing, because of this code:

impl Service<ServiceRequest> for ResourceService {
    type Response = ServiceResponse;
    type Error = Error;
    type Future = LocalBoxFuture<'static, Result<Self::Response, Self::Error>>;

    actix_service::always_ready!();

    fn call(&mut self, mut req: ServiceRequest) -> Self::Future {
        for route in self.routes.iter_mut() {
            if route.check(&mut req) {
                if let Some(ref app_data) = self.app_data {
                    req.add_data_container(app_data.clone());
                }
                return route.call(req);
            }
        }
        if let Some(ref app_data) = self.app_data {
            req.add_data_container(app_data.clone());
        }
        self.default.call(req)
    }
}

Guess I need to learn more about the actix-http and actix-service.

So, why can't Resource take a more generic serviceFactory, like Scope do? That's the origin of my confusion.

[fakeshadow]

It's designed not to. Resource is used to group a set of Route services and call them based on the Guard you define.
Resource or Scope are just used to construct some type impl Service trait. There is no functional difference between them and they behave differently because their state and service call logic.(Which is intended)

[felipero]

Makes sense. Thanks a lot for the answers, very helpful.
I'd love to contribute to the project, even if just with some documentation. Is there anything at the top of your head that I could help with?

[fakeshadow]

Thanks for asking.

We have a lot of issues across the domain projects you may find interest into.
The example repo also would like more examples to wide the coverage of different uses.
You can feel free to start new issue or PR if you find something thinking worth look into.