Using named Caches with HybridCache ?

[seifmostafa73]

I'm attempting to utilize a named FusionCache instance within my application. However, when I try to inject it as a HybridCache, I encounter a type mismatch error:

Cannot implicitly convert type 'ZiggyCreatures.Caching.Fusion.IFusionCache' to 'Microsoft.Extensions.Caching.Hybrid.HybridCache'.

Is there a recommended approach to use a named FusionCache instance directly as a HybridCache, or a workaround to resolve this type incompatibility?

[jodydonetti]

Hi @seifmostafa73 , sure thing!

How are you trying to do that? Can you post a code sample?

If you look at the docs you can see this:

Basically you can do this:

services.AddFusionCache("MyNamedCache")
    .AsHybridCache();

to use the cache named "MyNamedCache" as the HybridCache implementation.

Hope this helps, let me know.

[seifmostafa73]

yeah the issue is not creating the named instance for me, it's how to make services use that specific cache

as for my setup:

builder.Services.AddFusionCache("CallLogsCache") // this is the name of the cache instance
    .WithDefaultEntryOptions(options =>
    {
        options.Duration = TimeSpan.FromHours(3);
        options.FailSafeMaxDuration = TimeSpan.FromHours(5);
        options.IsFailSafeEnabled = true;
        options.FactorySoftTimeout = TimeSpan.FromSeconds(45); // if the factory takes longer than this, we will return the cached value
        options.EagerRefreshThreshold = 0.95f;
    })
    .WithSerializer(new FusionCacheNewtonsoftJsonSerializer(jsonSettings))
    .WithDistributedCache(new RedisCache(new RedisCacheOptions()
    {
        Configuration = redisConnectionString
    }))
    .AsHybridCache();

now since I want to use it with the HybridCache interface, I tried the following in my service:

private readonly HybridCache _hybridCache;

public CachedCallLogsService(ICallLogService decoratedService, HybridCache hybridCache)
{
    _decoratedService = decoratedService;
    _hybridCache = hybridCache;
}

but I can't find in the documentation any example on how to specify the cache instance without using Fusion interfaces directly. the only way I saw is using the IFusionCacheProvider, which then throws the type mismatch error I put in the original post.

[jodydonetti]

Hi @seifmostafa73 I'll try to make it clearer.

When you say (your code):

builder.Services.AddFusionCache("CallLogsCache")
    // ...
    .AsHybridCache(); // AS HYBRID

what you are saying is "when HybridCache is asked, return the FusionCache instance named "CallLogsCache"".

You don't need to specify the FusionCache name when asking for HybridCache.

But FusionCache can go one step further, meaning it already supports multiple named HybridCache instances: but since there's nothing like IFusionCacheProvider in the HybridCache world, the only way is via keyed services.

So if you do:

builder.Services.AddFusionCache("Foo")
    .AsKeyedHybridCache("Bar"); // AS *KEYED* HYBRID

you are saying is "when [FromKeyedServices("Bar")] HybridCache is asked, return the FusionCache instance named "Foo"".

The name of the FusionCache instance is NOT directly related to the FromKeyedServices key.

Some other examples.

If you do:

builder.Services.AddFusionCache()
    .AsKeyedHybridCache("Bar"); // AS *KEYED* HYBRID

you are saying is "when [FromKeyedServices("Bar")] HybridCache is asked, return the default FusionCache instance".

Hope this helps, let me know.

[seifmostafa73]

Exactly what I was looking for, thanks ! :)