Is it possible to have !Send handler for requests ?

[artem-tim]

Summary

I use a http request processing library which has a !Send constraint. Is it possible to run a multi-threaded axum server and have it assign a dedicated thread for each incoming request that would explicitly allow !Send ? I've initially created a Service, but then noticed that Router Layer cannot be used because of Send constraint for the service : L::Service: Service<Request> + Clone + Send + 'static

axum version

0.7

[davidpdrsn]

No that’s not possible. axum requires Send. Allowing !Send would basically require duplicating all the code because of how auto traits work in trait objects.

I think your best option is to spawn a dedicated thread and communicate with it via channels.

[artem-tim]

Thanks. In that case, would you recommend maybe using hyper directly rather than axum ?

[davidpdrsn]

Depends on your use case. Hyper is very low level.

[artem-tim]

Hmm my usecase is basically just that : apply a !Send http request processing function which returns an http::Response. The library was originally designed to work in web-worker context as wasm (which is inherently single threaded), and I'm trying emulate this single-threaded runtime on a custom http server. Still unsure of the best libraries for the job, so I wonder if axum is an appropriate solution