Serve 503 when PocketBase is unavailable across all content pages

Elternbeirat.Web/Features/Posts/PostList.razor.cs

@@ -1,36 +1,48 @@
-using System.Globalization;
 using Elternbeirat.Contracts;
 using Elternbeirat.PocketBase;
+using Elternbeirat.Web.Shared;
 using Microsoft.AspNetCore.Components;
 
 namespace Elternbeirat.Web.Features.Posts;
 
 public partial class PostList
 {
-    [LoggerMessage(Level = LogLevel.Warning, Message = "Could not load posts from PocketBase.")]
-    private static partial void LogLoadFailed(ILogger logger, Exception exception);
-
-    private static readonly CultureInfo German = CultureInfo.GetCultureInfo("de-DE");
+    [LoggerMessage(
+        Level = LogLevel.Error,
+        Message = "Could not load posts from PocketBase; content source is unavailable.")]
+    private static partial void LogSourceUnavailable(
+        ILogger logger,
+        Exception exception);
 
     [Inject]
-    private PocketBaseClient PocketBase { get; set; } = default!;
+    private PocketBaseClient PocketBase { get; set; } = null!;
 
     [Inject]
-    private ILogger<PostList> Logger { get; set; } = default!;
+    private ILogger<PostList> Logger { get; set; } = null!;
+
+    [CascadingParameter]
+    private HttpContext? HttpContext { get; set; }
 
     private IReadOnlyList<Post> _posts = [];
 
+    // Set when the content source could not be reached or read. The markup then
+    // shows a "temporarily unavailable" note instead of "no posts", matching the
+    // 503 this sets on the response.
+    private bool _unavailable;
+
     protected override async Task OnInitializedAsync()
     {
         try
         {
-            _posts = await PocketBase.GetPostsAsync();
+            _posts = await PocketBase.GetPostsAsync(HttpContext?.RequestAborted ?? CancellationToken.None);
         }
-        catch (HttpRequestException ex)
+        catch (PocketBaseUnavailableException exception)
         {
-            // Source unreachable -> show an empty list instead of a 500. The page
-            // stays up; the "keine Beiträge" note is rendered.
-            LogLoadFailed(Logger, ex);
+            // An empty list would claim there are no posts. The site works, its
+            // data store is down: 503 and an honest note.
+            LogSourceUnavailable(Logger, exception);
+            _unavailable = true;
+            SourceUnavailable.SetStatus(HttpContext);
         }
     }
 }