added file check task

Web.Server/Program.cs

@@ -26,6 +26,7 @@ public static void Main(string[] args)
                 builder.Services.AddHostedService<AppReleasesTask>();
                 builder.Services.AddHostedService<PortsReleasesTask>();
                 builder.Services.AddHostedService<ToolsReleasesTask>();
+                builder.Services.AddHostedService<FileCheckTask>();
             }
 
             builder.Services.AddSingleton<AppReleasesProvider>();

Web.Server/Tasks/FileCheckTask.cs

@@ -0,0 +1,68 @@
+using Web.Server.Helpers;
+
+namespace Web.Server.Tasks;
+
+public sealed class FileCheckTask : IHostedService, IDisposable
+{
+    private readonly ILogger<AppReleasesTask> _logger;
+    private readonly DatabaseContextFactory _dbContextFactory;
+    private readonly HttpClient _httpClient;
+
+    private Timer _timer;
+
+    public FileCheckTask(
+        ILogger<AppReleasesTask> logger,
+        DatabaseContextFactory dbContextFactory,
+        HttpClient httpClient
+        )
+    {
+        _logger = logger;
+        _dbContextFactory = dbContextFactory;
+        _httpClient = httpClient;
+    }
+
+    public Task StartAsync(CancellationToken stoppingToken)
+    {
+        _timer = new Timer(
+            DoWork,
+            null,
+            TimeSpan.Zero,
+            TimeSpan.FromHours(6)
+            );
+
+        return Task.CompletedTask;
+    }
+
+    private void DoWork(object? state)
+    {
+        _logger.LogInformation("File check started");
+
+        using var dbContext = _dbContextFactory.Get();
+        var files = dbContext.Versions.Select(v => v.DownloadUrl).ToList();
+
+        foreach (var file in files)
+        {
+            var result = _httpClient.GetAsync(file, HttpCompletionOption.ResponseHeadersRead).Result;
+
+            if (result is null || !result.IsSuccessStatusCode)
+            {
+                _logger.LogError($"File doesn't exist or unavailable: {file}");
+                continue;
+            }
+        }
+
+        _logger.LogInformation("File check ended");
+    }
+
+    public Task StopAsync(CancellationToken stoppingToken)
+    {
+        _timer.Change(Timeout.Infinite, 0);
+
+        return Task.CompletedTask;
+    }
+
+    public void Dispose()
+    {
+        _timer.Dispose();
+    }
+}