GGMM/GrossesMitaines/GrossesMitainesAPI/Services/DatabaseCacheService.cs
2022-10-25 09:27:19 -07:00

74 lines
2.5 KiB
C#

using GrossesMitainesAPI.Data;
using GrossesMitainesAPI.Models;
using Microsoft.EntityFrameworkCore;
namespace GrossesMitainesAPI.Services {
public class DatabaseCacheService {
private readonly IServiceScopeFactory _contextFactory; // https://entityframeworkcore.com/knowledge-base/51939451/how-to-use-a-database-context-in-a-singleton-service-
private readonly ILogger<DatabaseCacheService> _logger;
private Product[] _cache = new Product[1];
private bool _ok = false, _needUpd = true;
private PeriodicTimer _timer = new PeriodicTimer(TimeSpan.FromSeconds(10));
public DatabaseCacheService(ILogger<DatabaseCacheService> logger, IServiceScopeFactory scopeFactory) {
_contextFactory = scopeFactory;
_logger = logger;
_ok = UpdateCache();
_needUpd = !_ok;
UpdateJob();
}
private async void UpdateJob() {
while (await _timer.WaitForNextTickAsync())
if (_needUpd) {
_ok = UpdateCache();
_needUpd = !_ok;
}
}
private bool UpdateCache() {
try {
Product[] prods;
using (var scope = _contextFactory.CreateScope()) {
var db = scope.ServiceProvider.GetRequiredService<InventoryContext>();
prods = db.Products.ToArray();
}
lock (_cache) {
_cache = prods;
}
} catch (Exception e) {
_logger.LogError(e, "Erreur de mise à jour de cache.");
return false;
}
return true;
}
public bool isOk() { return _ok; }
public void askForRefresh() { _needUpd = true; }
public Product[]? GetCacheCopy() {
if (!_ok) return null;
Product[] copy;
try {
lock (_cache) {
copy = new Product[_cache.Length];
_cache.CopyTo(copy, 0);
}
} catch (Exception e) {
_logger.LogError(e, "Erreur de copie de cache.");
return null;
}
return copy;
}
public IQueryable<Product> queryCache() {
if (!_ok) return null;
try {
return _cache.AsQueryable();
} catch (Exception e) {
_logger.LogError(e, "Erreur de cache.");
return null;
}
}
}
}