Iceshrimp.NET/Iceshrimp.Backend/Core/Extensions/DistributedCacheExtensions.cs
2024-01-28 22:04:53 +01:00

44 lines
No EOL
1.5 KiB
C#

using System.Text.Json;
using Microsoft.Extensions.Caching.Distributed;
namespace Iceshrimp.Backend.Core.Extensions;
public static class DistributedCacheExtensions {
//TODO: named caches, CacheService? (that optionally uses StackExchange.Redis directly)?
//TODO: thread-safe locks to prevent fetching data more than once
//TODO: sliding window ttl?
//TODO: renew option on GetAsync and FetchAsync
//TODO: check that this actually works for complex types (sigh)
public static async Task<T?> GetAsync<T>(this IDistributedCache cache, string key) {
var buffer = await cache.GetAsync(key);
if (buffer == null || buffer.Length == 0) return default;
var stream = new MemoryStream(buffer);
try {
var data = await JsonSerializer.DeserializeAsync<T>(stream);
return data != null ? (T)data : default;
}
catch {
return default;
}
}
public static async Task<T> FetchAsync<T>(this IDistributedCache cache, string key, TimeSpan ttl,
Func<Task<T>> fetcher) {
var hit = await cache.GetAsync<T>(key);
if (hit != null) return hit;
var fetched = await fetcher();
await cache.SetAsync(key, fetched, ttl);
return fetched;
}
public static async Task SetAsync<T>(this IDistributedCache cache, string key, T data, TimeSpan ttl) {
using var stream = new MemoryStream();
await JsonSerializer.SerializeAsync(stream, data);
stream.Position = 0;
var options = new DistributedCacheEntryOptions { AbsoluteExpirationRelativeToNow = ttl };
await cache.SetAsync(key, stream.ToArray(), options);
}
}