How about Contains / Exists implementation for a key? about cachemanager

[MichaCo]

@sam-piper @keerthivasanm
Sorry that it took so long but it's finally implemented and will be in the next release.

[MichaCo]

Yup, sounds like a potential improvement

[killergege]

I'm a bit surprised that this is missing, it's a basic feature for a cache manager !
How do you know that the value returned by Get is a cached value or a default value because the key doesn't exist ?
To me it sounds dangerous to return a value if the key doesn't exist...

[MichaCo]

@killergege That's the normal behavior of caches. If the key doesn't exist, you cannot return anything. And CacheManager returns default(TCacheValue) which is null for value types etc...

The only other option would be throwing a not found exception, which would cause all kinds of other oddness because then you'd have to try/catch every cache call... Which is even worse than a null check...

That being said, a TryGet and/or Exists method will be helpful for non value types.
Although, you can always use the GetCacheItem method which will always return null if a key doesn't exist, independent of the TCacheValue

[jzabroski]

Agreed with MichaC. Null is a meaningless value. If you want a way to reify
a null, create a Maybe wrapper type. There are many projects on github
which provide not only Maybe but Option type as well (to denote optional
parameters/values).
On May 11, 2016 1:08 PM, "MichaC" [email protected] wrote:

@killergege https://github.com/killergege That's the normal behavior of
caches. If the key doesn't exist, you cannot return anything. And
CacheManager returns default(TCacheValue) which is null for value types
etc...

The only other option would be throwing a not found exception, which would
cause all kinds of other oddness because then you'd have to try/catch every
cache call... Which is even worse than a null check...

That being said, a TryGet and/or Exists method will be helpful for non
value types.
Although, you can always use the GetCacheItem method which will always
return null if a key doesn't exist, independent of the TCacheValue

—
You are receiving this because you are subscribed to this thread.
Reply to this email directly or view it on GitHub
#46 (comment)

[sam-piper]

+1 - we would really like this feature too. We have cache loading algorithms that we want to transfer from a previous caching implementation that need to test for the existence of keys without transferring any values from the Redis layer, otherwise performance suffers.

For now I'll have to plug this gap manually, would be great to have official support in the CacheManager API.