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using System;
using System.Diagnostics.CodeAnalysis;
using System.Threading;
using System.Threading.Tasks;
using Hangfire;
using Microsoft.Extensions.Hosting;
using StardewModdingAPI.Toolkit;
using StardewModdingAPI.Toolkit.Framework.Clients.Wiki;
using StardewModdingAPI.Web.Framework.Caching.Mods;
using StardewModdingAPI.Web.Framework.Caching.Wiki;
namespace StardewModdingAPI.Web
{
/// <summary>A hosted service which runs background data updates.</summary>
/// <remarks>Task methods need to be static, since otherwise Hangfire will try to serialize the entire instance.</remarks>
internal class BackgroundService : IHostedService, IDisposable
{
/*********
** Fields
*********/
/// <summary>The background task server.</summary>
private static BackgroundJobServer? JobServer;
/// <summary>The cache in which to store wiki metadata.</summary>
private static IWikiCacheRepository? WikiCache;
/// <summary>The cache in which to store mod data.</summary>
private static IModCacheRepository? ModCache;
/// <summary>Whether the service has been started.</summary>
[MemberNotNullWhen(true, nameof(BackgroundService.JobServer), nameof(BackgroundService.WikiCache), nameof(BackgroundService.ModCache))]
private static bool IsStarted { get; set; }
/*********
** Public methods
*********/
/****
** Hosted service
****/
/// <summary>Construct an instance.</summary>
/// <param name="wikiCache">The cache in which to store wiki metadata.</param>
/// <param name="modCache">The cache in which to store mod data.</param>
/// <param name="hangfireStorage">The Hangfire storage implementation.</param>
[SuppressMessage("ReSharper", "UnusedParameter.Local", Justification = "The Hangfire reference forces it to initialize first, since it's needed by the background service.")]
public BackgroundService(IWikiCacheRepository wikiCache, IModCacheRepository modCache, JobStorage hangfireStorage)
{
BackgroundService.WikiCache = wikiCache;
BackgroundService.ModCache = modCache;
}
/// <summary>Start the service.</summary>
/// <param name="cancellationToken">Tracks whether the start process has been aborted.</param>
public Task StartAsync(CancellationToken cancellationToken)
{
this.TryInit();
// set startup tasks
BackgroundJob.Enqueue(() => BackgroundService.UpdateWikiAsync());
BackgroundJob.Enqueue(() => BackgroundService.RemoveStaleModsAsync());
// set recurring tasks
RecurringJob.AddOrUpdate(() => BackgroundService.UpdateWikiAsync(), "*/10 * * * *"); // every 10 minutes
RecurringJob.AddOrUpdate(() => BackgroundService.RemoveStaleModsAsync(), "0 * * * *"); // hourly
BackgroundService.IsStarted = true;
return Task.CompletedTask;
}
/// <summary>Triggered when the application host is performing a graceful shutdown.</summary>
/// <param name="cancellationToken">Tracks whether the shutdown process should no longer be graceful.</param>
public async Task StopAsync(CancellationToken cancellationToken)
{
BackgroundService.IsStarted = false;
if (BackgroundService.JobServer != null)
await BackgroundService.JobServer.WaitForShutdownAsync(cancellationToken);
}
/// <summary>Performs application-defined tasks associated with freeing, releasing, or resetting unmanaged resources.</summary>
public void Dispose()
{
BackgroundService.IsStarted = false;
BackgroundService.JobServer?.Dispose();
}
/****
** Tasks
****/
/// <summary>Update the cached wiki metadata.</summary>
[AutomaticRetry(Attempts = 3, DelaysInSeconds = new[] { 30, 60, 120 })]
public static async Task UpdateWikiAsync()
{
if (!BackgroundService.IsStarted)
throw new InvalidOperationException($"Must call {nameof(BackgroundService.StartAsync)} before scheduling tasks.");
WikiModList wikiCompatList = await new ModToolkit().GetWikiCompatibilityListAsync();
BackgroundService.WikiCache.SaveWikiData(wikiCompatList.StableVersion, wikiCompatList.BetaVersion, wikiCompatList.Mods);
}
/// <summary>Remove mods which haven't been requested in over 48 hours.</summary>
public static Task RemoveStaleModsAsync()
{
if (!BackgroundService.IsStarted)
throw new InvalidOperationException($"Must call {nameof(BackgroundService.StartAsync)} before scheduling tasks.");
BackgroundService.ModCache.RemoveStaleMods(TimeSpan.FromHours(48));
return Task.CompletedTask;
}
/*********
** Private method
*********/
/// <summary>Initialize the background service if it's not already initialized.</summary>
/// <exception cref="InvalidOperationException">The background service is already initialized.</exception>
private void TryInit()
{
if (BackgroundService.JobServer != null)
throw new InvalidOperationException("The scheduler service is already started.");
BackgroundService.JobServer = new BackgroundJobServer();
}
}
}
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