88 lines
2.9 KiB
C#
88 lines
2.9 KiB
C#
using System;
|
|
using System.Collections.Generic;
|
|
using System.Threading;
|
|
using System.Threading.Tasks;
|
|
using Data.Abstractions;
|
|
using Microsoft.EntityFrameworkCore;
|
|
using Microsoft.Extensions.Logging;
|
|
|
|
namespace Data.Helpers
|
|
{
|
|
public class DataValueCache<T, V> : IDataValueCache<T, V> where T : class
|
|
{
|
|
private readonly ILogger _logger;
|
|
private readonly IDatabaseContextFactory _contextFactory;
|
|
private readonly Dictionary<string, CacheState> _cacheStates = new Dictionary<string, CacheState>();
|
|
private const int DefaultExpireMinutes = 15;
|
|
|
|
private class CacheState
|
|
{
|
|
public string Key { get; set; }
|
|
public DateTime LastRetrieval { get; set; }
|
|
public TimeSpan ExpirationTime { get; set; }
|
|
public Func<DbSet<T>, CancellationToken, Task<V>> Getter { get; set; }
|
|
public V Value { get; set; }
|
|
|
|
public bool IsExpired => ExpirationTime != TimeSpan.MaxValue &&
|
|
(DateTime.Now - LastRetrieval.Add(ExpirationTime)).TotalSeconds > 0;
|
|
}
|
|
|
|
public DataValueCache(ILogger<DataValueCache<T, V>> logger, IDatabaseContextFactory contextFactory)
|
|
{
|
|
_logger = logger;
|
|
_contextFactory = contextFactory;
|
|
}
|
|
|
|
public void SetCacheItem(Func<DbSet<T>, CancellationToken, Task<V>> getter, string key,
|
|
TimeSpan? expirationTime = null)
|
|
{
|
|
if (_cacheStates.ContainsKey(key))
|
|
{
|
|
_logger.LogDebug("Cache key {key} is already added", key);
|
|
return;
|
|
}
|
|
|
|
var state = new CacheState()
|
|
{
|
|
Key = key,
|
|
Getter = getter,
|
|
ExpirationTime = expirationTime ?? TimeSpan.FromMinutes(DefaultExpireMinutes)
|
|
};
|
|
|
|
_cacheStates.Add(key, state);
|
|
}
|
|
|
|
public async Task<V> GetCacheItem(string keyName, CancellationToken cancellationToken = default)
|
|
{
|
|
if (!_cacheStates.ContainsKey(keyName))
|
|
{
|
|
throw new ArgumentException("No cache found for key {key}", keyName);
|
|
}
|
|
|
|
var state = _cacheStates[keyName];
|
|
|
|
if (state.IsExpired || state.Value == null)
|
|
{
|
|
await RunCacheUpdate(state, cancellationToken);
|
|
}
|
|
|
|
return state.Value;
|
|
}
|
|
|
|
private async Task RunCacheUpdate(CacheState state, CancellationToken token)
|
|
{
|
|
try
|
|
{
|
|
await using var context = _contextFactory.CreateContext(false);
|
|
var set = context.Set<T>();
|
|
var value = await state.Getter(set, token);
|
|
state.Value = value;
|
|
state.LastRetrieval = DateTime.Now;
|
|
}
|
|
catch (Exception ex)
|
|
{
|
|
_logger.LogError(ex, "Could not get cached value for {key}", state.Key);
|
|
}
|
|
}
|
|
}
|
|
} |