Keep remote and local Redfish resources in sync

[tadeboro]

When we issue a request to the Redfish service that modifies some resources, we should also update the resource's local representation with a fresh set of data and invalidate the cache entries.

[miha-plesko]

Basically we need to fully invalidate cache everytime we execute action, right? Because we can never know what the action is about; they are all POST.

[tadeboro]

I did not think about this much yet, but this how I would handle various modifications:

• PATCH: refresh the local resource (this also refreshes the cache).
• DELETE: remove an entry from the cache.

POST is a bit more complicated because we can use it in two different situations:

• when creating a new resource and
• when executing an action.

When we execute an action, we do not have enough information to do anything meaningful. Creating a new resource, on the other hand, also modifies the item's parent collection, which means that we need to invalidate the cache entry for it.