feat: auto-update sitemap when events are added/updated/removed

- Use tag-based cache for sitemap event list (events-sitemap)
- Add POST /api/revalidate endpoint (secret-protected) to trigger revalidation
- Backend calls revalidation after event create/update/delete
- Add REVALIDATE_SECRET to .env.example (frontend + backend)

Co-authored-by: Cursor <cursoragent@cursor.com>

backend/.env.example

@@ -21,6 +21,10 @@ PORT=3001
 API_URL=http://localhost:3001
 FRONTEND_URL=http://localhost:3002
 
+# Revalidation secret (shared with frontend for on-demand cache revalidation)
+# Must match the REVALIDATE_SECRET in frontend/.env
+REVALIDATE_SECRET=change-me-to-a-random-secret
+
 # Payment Providers (optional)
 STRIPE_SECRET_KEY=
 STRIPE_WEBHOOK_SECRET=

backend/src/routes/events.ts

@@ -15,6 +15,28 @@ interface UserContext {
 
 const eventsRouter = new Hono<{ Variables: { user: UserContext } }>();
 
+// Trigger frontend sitemap revalidation (fire-and-forget)
+function revalidateSitemap() {
+  const frontendUrl = process.env.FRONTEND_URL || 'http://localhost:3002';
+  const secret = process.env.REVALIDATE_SECRET;
+  if (!secret) {
+    console.warn('REVALIDATE_SECRET not set, skipping sitemap revalidation');
+    return;
+  }
+  fetch(`${frontendUrl}/api/revalidate`, {
+    method: 'POST',
+    headers: { 'Content-Type': 'application/json' },
+    body: JSON.stringify({ secret, tag: 'events-sitemap' }),
+  })
+    .then((res) => {
+      if (!res.ok) console.error('Sitemap revalidation failed:', res.status);
+      else console.log('Sitemap revalidation triggered');
+    })
+    .catch((err) => {
+      console.error('Sitemap revalidation error:', err.message);
+    });
+}
+
 // Helper to normalize event data for API response
 // PostgreSQL decimal returns strings, booleans are stored as integers
 function normalizeEvent(event: any) {
@@ -337,6 +359,9 @@ eventsRouter.post('/', requireAuth(['admin', 'organizer']), zValidator('json', c
   
   await (db as any).insert(events).values(newEvent);
   
+  // Revalidate sitemap when a new event is created
+  revalidateSitemap();
+  
   // Return normalized event data
   return c.json({ event: normalizeEvent(newEvent) }, 201);
 });
@@ -373,6 +398,9 @@ eventsRouter.put('/:id', requireAuth(['admin', 'organizer']), zValidator('json',
     (db as any).select().from(events).where(eq((events as any).id, id))
   );
   
+  // Revalidate sitemap when an event is updated (status/dates may have changed)
+  revalidateSitemap();
+  
   return c.json({ event: normalizeEvent(updated) });
 });
 
@@ -429,6 +457,9 @@ eventsRouter.delete('/:id', requireAuth(['admin']), async (c) => {
   // Finally delete the event
   await (db as any).delete(events).where(eq((events as any).id, id));
   
+  // Revalidate sitemap when an event is deleted
+  revalidateSitemap();
+  
   return c.json({ message: 'Event deleted successfully' });
 });
 

frontend/.env.example

@@ -21,6 +21,10 @@ NEXT_PUBLIC_EMAIL=hola@spanglish.com.py
 NEXT_PUBLIC_TELEGRAM=spanglish_py
 NEXT_PUBLIC_TIKTOK=spanglishsocialpy
 
+# Revalidation secret (shared between frontend and backend for on-demand cache revalidation)
+# Must match the REVALIDATE_SECRET in backend/.env
+REVALIDATE_SECRET=change-me-to-a-random-secret
+
 # Plausible Analytics (optional - leave empty to disable tracking)
 NEXT_PUBLIC_PLAUSIBLE_URL=https://analytics.azzamo.net
 NEXT_PUBLIC_PLAUSIBLE_DOMAIN=spanglishcommunity.com

frontend/src/app/api/revalidate/route.ts

@@ -0,0 +1,27 @@
+import { revalidateTag } from 'next/cache';
+import { NextRequest, NextResponse } from 'next/server';
+
+export async function POST(request: NextRequest) {
+  try {
+    const body = await request.json();
+    const { secret, tag } = body;
+
+    // Validate the revalidation secret
+    const revalidateSecret = process.env.REVALIDATE_SECRET;
+    if (!revalidateSecret || secret !== revalidateSecret) {
+      return NextResponse.json({ error: 'Invalid secret' }, { status: 401 });
+    }
+
+    // Validate tag
+    const allowedTags = ['events-sitemap'];
+    if (!tag || !allowedTags.includes(tag)) {
+      return NextResponse.json({ error: 'Invalid tag' }, { status: 400 });
+    }
+
+    revalidateTag(tag);
+
+    return NextResponse.json({ revalidated: true, tag, now: Date.now() });
+  } catch {
+    return NextResponse.json({ error: 'Failed to revalidate' }, { status: 500 });
+  }
+}

frontend/src/app/sitemap.ts

@@ -12,7 +12,7 @@ interface Event {
 async function getPublishedEvents(): Promise<Event[]> {
   try {
     const response = await fetch(`${apiUrl}/api/events?status=published`, {
-      next: { revalidate: 3600 }, // Cache for 1 hour
+      next: { tags: ['events-sitemap'] },
     });
     if (!response.ok) return [];
     const data = await response.json();