Add support for operation interceptors

[dpacheco-groupieticket]

I would like to request support for operation interceptors, similar to what's available in other frameworks. My primary use case is to implement authorization checks before operations are executed.

Currently, there doesn't appear to be a straightforward way to intercept operations before they reach the actual implementation. This would be extremely valuable for cross-cutting concerns like:

• Authorization/authentication
• Request validation
• Logging
• Metrics collection

[mtdowling]

For the client or server? The client already has a rich set of abstractions, including interceptors.

[dpacheco-groupieticket]

Apologize for not being clear, I mean for the server. Thanks!

[lizarazukevin]

Following up on this thread, I am using this library software.amazon.smithy.java:server-netty to handle my generated types and server stubs but I can't seem to expose the headers for authenticating JWTs.

I believe this information might've been stored in the RequestContext but all I see is a TODO to fill with more stuff.

package software.amazon.smithy.java.server;

// TODO Fill with more stuff.
public interface RequestContext {

    String getRequestId();
}

I was then pointed to possibly implement an interceptor at theNettyServiceProvider level but it all seems to be locked down, just wondering when that will get done.