Is it possible to avoid caching a value altogether when using adaptive caching ?

[EnricoMassone]

I'm looking for a way to avoid caching a value when using the adaptive caching pattern.

What I would like to do is represented by the following snippet:

var id = 42;

// WITH ADAPTIVE CACHING: THE DURATION DEPENDS ON THE OBJECT BEING CACHED
var product = cache.GetOrSet<Product>(
    $"product:{id}",
    (ctx, ct) => {
        var product = GetProductFromDb(id, ct);

        if (product is null) {
            // CACHE null FOR 5 minutes
            ctx.Options.Duration = TimeSpan.FromMinutes(5);
        } else if (product.LastUpdatedAt > DateTime.UtcNow.AddDays(-1)) {
            // CACHE PRODUCTS UPDATED IN THE LAST DAY FOR 1 MIN
            ctx.Options.Duration = TimeSpan.FromMinutes(1);
        } else if (product.LastUpdatedAt > DateTime.UtcNow.AddDays(-10)) {
            // CACHE PRODUCTS UPDATED IN THE LAST 10 DAYS FOR 10 MIN
            ctx.Options.Duration = TimeSpan.FromMinutes(10);
        } else {
            // SKIP CACHING FOR ANY OTHER PRODUCT
            // what should I do here ? 
        }

        return product;
    },
    options => options.SetDuration(TimeSpan.FromMinutes(1)) // DEFAULT: 1 MIN
);

Notice that in the else branch I want to skip caching the value entirely, both at the L1 and L2 level.

What is the best way to achieve this with Fusion Cache ? I can think of some alternatives:

• set a duration of zero in the else branch (with the same api used in the other branches)
• throw an exception from inside the factory

Is there any better approach to solve this problem ?

I noticed that on the FusionCacheEntryOptions class there are the properties SkipDistributedCache and SkipMemoryCache. Should I use this one ?

Thanks for helping.

[anntnzrb]

Set ctx.Options.SkipMemoryCacheWrite = true and ctx.Options.SkipDistributedCacheWrite = true in your else branch. This skips caching at both L1 and L2 levels without writing anything. Better than Duration = TimeSpan.Zero which still writes (then expires). See /src/ZiggyCreatures.FusionCache/FusionCacheEntryOptions.cs:409-422.

[jodydonetti]

Hi @EnricoMassone

I'm looking for a way to avoid caching a value when using the adaptive caching pattern.
[...]
I noticed that on the FusionCacheEntryOptions class there are the properties SkipDistributedCache and SkipMemoryCache. Should I use this one ?

Yes, as mentioned by @anntnzrb (thanks!) you can use the 2 "skip write" options.

Hope this helps.

[EnricoMassone]

Thanks @jodydonetti and @anntnzrb for the help with this topic. Do you think it is valuable to document this pattern ? If it is, I can maybe propose a pull request to add a note about this to the docs.
I think it is great that Fusion Cache offers a built-in idiomatic way to do so. Solving the same problem with Hybrid Cache, for example, is way less idiomatic.

[EnricoMassone]

Hello @jodydonetti I've created a pull request to document this pattern.

[jodydonetti]

Thanks @EnricoMassone , merged!