Serve 503 when PocketBase is unavailable across all content pages

Elternbeirat.Web/Features/Faqs/FaqList.razor.cs

@@ -1,13 +1,18 @@
 using Elternbeirat.Contracts;
 using Elternbeirat.PocketBase;
+using Elternbeirat.Web.Shared;
 using Microsoft.AspNetCore.Components;
 
 namespace Elternbeirat.Web.Features.Faqs;
 
 public partial class FaqList
 {
-    [LoggerMessage(Level = LogLevel.Warning, Message = "Could not load FAQs from PocketBase.")]
-    private static partial void LogLoadFailed(ILogger logger, Exception exception);
+    [LoggerMessage(
+        Level = LogLevel.Error,
+        Message = "Could not load FAQs from PocketBase; content source is unavailable.")]
+    private static partial void LogSourceUnavailable(
+        ILogger logger,
+        Exception exception);
 
     // German heading per topic. Unknown topics fall back to the raw key so a new
     // topic in PocketBase still shows up rather than being silently dropped.
@@ -21,28 +26,38 @@ public partial class FaqList
         };
 
     [Inject]
-    private PocketBaseClient PocketBase { get; set; } = default!;
+    private PocketBaseClient PocketBase { get; set; } = null!;
 
     [Inject]
-    private ILogger<FaqList> Logger { get; set; } = default!;
+    private ILogger<FaqList> Logger { get; set; } = null!;
+
+    [CascadingParameter]
+    private HttpContext? HttpContext { get; set; }
 
     private IReadOnlyList<IGrouping<string, Faq>> _groups = [];
 
+    // Set when the content source could not be reached or read. The markup then
+    // shows a "temporarily unavailable" note instead of "no questions", matching
+    // the 503 this sets on the response.
+    private bool _unavailable;
+
     protected override async Task OnInitializedAsync()
     {
         try
         {
-            var faqs = await PocketBase.GetFaqsAsync();
+            var faqs = await PocketBase.GetFaqsAsync(HttpContext?.RequestAborted ?? CancellationToken.None);
             _groups = [.. faqs.GroupBy(faq => faq.Topic)];
         }
-        catch (HttpRequestException ex)
+        catch (PocketBaseUnavailableException exception)
         {
-            // Source unreachable -> show an empty page instead of a 500. The page
-            // stays up; the "keine Fragen" note is rendered.
-            LogLoadFailed(Logger, ex);
+            // An empty page would claim there are no questions. The site works, its
+            // data store is down: 503 and an honest note.
+            LogSourceUnavailable(Logger, exception);
+            _unavailable = true;
+            SourceUnavailable.SetStatus(HttpContext);
         }
     }
 
-    private static string TopicLabel(string topic) =>
-        TopicLabels.TryGetValue(topic, out var label) ? label : topic;
+    private static string TopicLabel(string topic)
+        => TopicLabels.GetValueOrDefault(topic, topic);
 }