Serve 503 when PocketBase is unavailable across all content pages

Elternbeirat.Web/Program.cs

@@ -13,7 +13,7 @@ builder.Services.AddRazorComponents();
 // comes from configuration: appsettings for local dev, the PocketBase__BaseUrl
 // env var on the server (see compose.yaml).
 var pocketBaseUrl = builder.Configuration["PocketBase:BaseUrl"]
-    ?? throw new InvalidOperationException("PocketBase:BaseUrl is not configured.");
+                    ?? throw new InvalidOperationException("PocketBase:BaseUrl is not configured.");
 builder.Services.AddHttpClient<PocketBaseClient>(client =>
     client.BaseAddress = new Uri(pocketBaseUrl));
 
@@ -24,23 +24,26 @@ var app = builder.Build();
 // as HTTP and with the proxy IP instead of the client IP.
 // KnownNetworks/KnownProxies are deliberately empty because only NPM reaches
 // the container.
-app.UseForwardedHeaders(new ForwardedHeadersOptions
-{
-    ForwardedHeaders = ForwardedHeaders.XForwardedFor | ForwardedHeaders.XForwardedProto,
-    KnownIPNetworks = { },
-    KnownProxies = { }
-});
+app.UseForwardedHeaders(
+    new ForwardedHeadersOptions
+    {
+        ForwardedHeaders = ForwardedHeaders.XForwardedFor | ForwardedHeaders.XForwardedProto
+    });
 
 // Configure the HTTP request pipeline.
-if (!app.Environment.IsDevelopment())
+if (app.Environment.IsDevelopment() is false)
 {
     app.UseExceptionHandler("/Error", createScopeForErrors: true);
     // No UseHsts() and no UseHttpsRedirection(): NPM sets HSTS and terminates
     // TLS. Both here would create a redirect loop behind the proxy.
 }
 
-app.UseStatusCodePagesWithReExecute("/not-found", createScopeForStatusCodePages: true);
-
+// No UseStatusCodePagesWithReExecute: the Router renders the NotFoundPage
+// (Pages.NotFound) in process for both an unmatched route and an explicit
+// NavigationManager.NotFound() from a component (see Routes.razor). Re-executing
+// every error code to /not-found would also turn a 503 (content source down) into
+// a "not found" page; leaving it out lets those components keep their own
+// "temporarily unavailable" markup and 503 status.
 app.UseAntiforgery();
 
 app.MapStaticAssets();
@@ -49,14 +52,14 @@ app.MapRazorComponents<App>();
 // Subscribable calendar feed of all events. A minimal API endpoint rather than
 // a Razor page because it returns text/calendar, not HTML. Reads from PocketBase
 // per request; an unreachable source yields an empty calendar, not a 500.
-app.MapGet("/events.ics", async (PocketBaseClient pocketBase) =>
+app.MapGet("/events.ics", async (PocketBaseClient pocketBase, CancellationToken token) =>
 {
     IReadOnlyList<Event> events;
     try
     {
-        events = await pocketBase.GetEventsAsync();
+        events = await pocketBase.GetEventsAsync(token);
     }
-    catch (HttpRequestException)
+    catch (PocketBaseUnavailableException)
     {
         events = [];
     }