Serve 503 when PocketBase is unavailable across all content pages

Elternbeirat.Web/Features/Embeds/EventsEmbed.razor.cs

@@ -6,14 +6,24 @@ namespace Elternbeirat.Web.Features.Embeds;
 
 public partial class EventsEmbed
 {
-    [LoggerMessage(Level = LogLevel.Warning, Message = "Could not load events for an embed from PocketBase.")]
-    private static partial void LogLoadFailed(ILogger logger, Exception exception);
+    // Number of upcoming events shown in the teaser; the full list is one link away.
+    private const int TeaserCount = 3;
+
+    [LoggerMessage(
+        Level = LogLevel.Warning,
+        Message = "Could not load events for an embed from PocketBase; the teaser is omitted.")]
+    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<EventsEmbed> Logger { get; set; } = default!;
+    private ILogger<EventsEmbed> Logger { get; set; } = null!;
+
+    [CascadingParameter]
+    private HttpContext? HttpContext { get; set; }
 
     private IReadOnlyList<Event> _upcoming = [];
 
@@ -22,22 +32,25 @@ public partial class EventsEmbed
         IReadOnlyList<Event> events;
         try
         {
-            events = await PocketBase.GetEventsAsync();
+            events = await PocketBase.GetEventsAsync(HttpContext?.RequestAborted ?? CancellationToken.None);
         }
-        catch (HttpRequestException ex)
+        catch (PocketBaseUnavailableException exception)
         {
-            // Source unreachable -> show no teaser instead of a 500.
-            LogLoadFailed(Logger, ex);
+            // Only part of the page fails: omit the teaser, keep the page (and its
+            // 200) intact. A missing teaser is degraded, not broken.
+            LogSourceUnavailable(Logger, exception);
             return;
         }
 
-        // Teaser: the three soonest upcoming events, earliest first. An event
-        // earlier today still counts as upcoming.
+        // Teaser: the soonest upcoming events, earliest first. An event earlier
+        // today still counts as upcoming.
         var today = DateOnly.FromDateTime(DateTime.Today);
-        _upcoming = events
-            .Where(e => DateOnly.FromDateTime(e.Start) >= today)
-            .OrderBy(e => e.Start)
-            .Take(3)
-            .ToList();
+        _upcoming =
+        [
+            .. events
+                .Where(@event => DateOnly.FromDateTime(@event.Start) >= today)
+                .OrderBy(@event => @event.Start)
+                .Take(TeaserCount)
+        ];
     }
 }