martinitus / osgiliath-rs Goto Github PK

One of the nice features of layers provided by the tower framework, is that they can enrich/manipulate/process metadata that is attached with the requests and responses (e.g. HTTP Headers).
It would be nice to have a mechanism to provide extra metadata with the request/response enums. One possibility would be to use generic (Request|Response)Data structures which are templated with the actual trait specific generated request response enums.

Something like

struct<T> Response{
  headers: HashMap<String,String>
  body: T // This would be the macro generated TheTraitResponse
 }

Convenience converters From/Into from TheTraitResponse to Response<TheTraitResponse> could also be created.

The current hacks essentially unwrap and panic at various locations.
Instead it would be good to use appropriate result types.

It might be best to support only async traits that exclusively use results as return values (even for Unit returns) in their methods. Otherwise there is sort of a symmetry break when going from async trait to service back to async trait. One can see this in the generated blanket implementations let response = self.call(#request_ident::#variant_ident {#(#args),*}).await.unwrap();. Where instead of unwrapping, an error from the tower.call invocation should be mapped to the async trait result type instead.