[Validator] Optimize fetching the same external resource multiple times

[ewoutkramer]

Somewhere there should be caching involved.....but how to go about cache invalidation?

[wmrutten]

CachedResolver exposes InvalidateByUri and InvalidateByCanonicalUri methods for cache invalidation.
Access to the internal data structure is synchronized, so it should be thread safe.
E.g. while the validator is running, another thread could invalidate a cache entry. Subsequent requests to for that entry will cause the CachedResolver to try and re-load the requested artifact from the backing source.

[ewoutkramer]

You're right, but I am not fetching external resources using an IResourceResolver I think. Or maybe I do ;-) Well, I'll double check and if not see how to integrate IResourceResolver into resolving external (instance) references (not necessarily to conformance resources)

[marcovisserFurore]

External resources are fetched by subscribing to the event OnExternalResolutionNeeded. When you are not doing that, the Validator tries to resolve the resource with his own IResourceResolver, which is not cached.
When you are using the OnExternalResolutionNeeded you can control, as an end-user, the way how external resources are fetched and thus implement a caching mechanism for that as well.