fix(review-2): critical — repair comment posting + close export data leak

CR1: the lightbox comment button POSTed to /upload/{id}/comment (singular);
     no such route exists, so every UI-submitted comment 404'd and was lost.
     Fixed to /comments (plural). The prior e2e passed because its seed helper
     POSTs the API directly — added comment-ui.spec.ts which drives the real
     component so this can't regress silently again.

CR2: export archives (Gallery.zip / Memories.zip / HTML viewer) were written
     under media_path, which is a public ServeDir — so GET /media/exports/
     Gallery.zip served the entire event (every photo, caption, comment,
     uploader name) to any anonymous visitor at a guessable URL, bypassing the
     ticket + release gate. Moved exports to a separate EXPORT_PATH (=/exports)
     on its own volume (Dockerfile chown, compose volume, gated handler reads
     the new path). export-leak.spec.ts asserts /media/exports/Gallery.zip → 404.

Riders (git can't split hunks): LightboxModal also gains H3 live-eviction on
comment-deleted/upload-deleted; config.rs also wires compression_concurrency
from boot config (medium).

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

.env.example

@@ -32,6 +32,9 @@ EVENT_SLUG=max-maria-2026
 
 # ── Storage ───────────────────────────────────────────────────────────────────
 MEDIA_PATH=/media
+# Export archives (Gallery.zip / Memories.zip). MUST be outside MEDIA_PATH —
+# /media is publicly served, so exports here would be downloadable without auth.
+EXPORT_PATH=/exports
 
 # ── Upload limits ─────────────────────────────────────────────────────────────
 DEFAULT_MAX_IMAGE_SIZE_MB=20

backend/Dockerfile

@@ -20,15 +20,17 @@ FROM alpine:3.21
 
 RUN apk add --no-cache ca-certificates ffmpeg
 
-# Run as a non-root user. Pre-create and chown the media mount path so the fresh
-# named volume inherits the non-root ownership (Docker seeds an empty named volume
-# from the image directory, preserving its uid/gid) and uploads can be written.
+# Run as a non-root user. Pre-create and chown the media + export mount paths so
+# the fresh named volumes inherit the non-root ownership (Docker seeds an empty
+# named volume from the image directory, preserving its uid/gid) and uploads +
+# export archives can be written. Exports live OUTSIDE /media on purpose so the
+# public media ServeDir can't reach them.
 RUN addgroup -S app && adduser -S app -G app
 
 WORKDIR /app
 COPY --from=builder /app/target/release/eventsnap-backend ./
 
-RUN mkdir -p /media && chown -R app:app /app /media
+RUN mkdir -p /media /exports && chown -R app:app /app /media /exports
 USER app
 
 EXPOSE 3000

backend/src/config.rs

@@ -56,7 +56,13 @@ pub struct AppConfig {
     pub event_name: String,
     pub event_slug: String,
     pub media_path: PathBuf,
+    /// Where export archives are written. MUST be outside `media_path` — that
+    /// directory is served by a public `ServeDir`, so a predictable archive name
+    /// under it would leak the whole gallery to anonymous visitors.
+    pub export_path: PathBuf,
     pub app_port: u16,
+    /// Number of concurrent media compression workers (read once at boot).
+    pub compression_concurrency: usize,
 }
 
 impl AppConfig {
@@ -86,10 +92,18 @@ impl AppConfig {
             media_path: PathBuf::from(
                 std::env::var("MEDIA_PATH").unwrap_or_else(|_| "/media".to_string()),
             ),
+            export_path: PathBuf::from(
+                std::env::var("EXPORT_PATH").unwrap_or_else(|_| "/exports".to_string()),
+            ),
             app_port: std::env::var("APP_PORT")
                 .unwrap_or_else(|_| "3000".to_string())
                 .parse()
                 .context("APP_PORT must be a number")?,
+            compression_concurrency: std::env::var("COMPRESSION_WORKER_CONCURRENCY")
+                .ok()
+                .and_then(|v| v.parse().ok())
+                .filter(|&n| n >= 1)
+                .unwrap_or(2),
         })
     }
 }

backend/src/services/export.rs

@@ -87,15 +87,17 @@ pub fn spawn_export_jobs(
     event_name: String,
     pool: PgPool,
     media_path: PathBuf,
+    export_path: PathBuf,
     sse_tx: broadcast::Sender<SseEvent>,
 ) {
     let pool2 = pool.clone();
     let media_path2 = media_path.clone();
+    let export_path2 = export_path.clone();
     let sse_tx2 = sse_tx.clone();
     let event_name2 = event_name.clone();
 
     tokio::spawn(async move {
-        if let Err(e) = run_zip_export(event_id, &pool, &media_path, &sse_tx).await {
+        if let Err(e) = run_zip_export(event_id, &pool, &media_path, &export_path, &sse_tx).await {
             tracing::error!("ZIP export failed for event {event_id}: {e:#}");
             mark_failed(&pool, event_id, "zip", &e.to_string()).await;
         }
@@ -104,7 +106,7 @@ pub fn spawn_export_jobs(
 
     tokio::spawn(async move {
         if let Err(e) =
-            run_html_export(event_id, &event_name2, &pool2, &media_path2, &sse_tx2).await
+            run_html_export(event_id, &event_name2, &pool2, &media_path2, &export_path2, &sse_tx2).await
         {
             tracing::error!("HTML export failed for event {event_id}: {e:#}");
             mark_failed(&pool2, event_id, "html", &e.to_string()).await;
@@ -119,6 +121,7 @@ async fn run_zip_export(
     event_id: Uuid,
     pool: &PgPool,
     media_path: &Path,
+    export_path: &Path,
     sse_tx: &broadcast::Sender<SseEvent>,
 ) -> Result<()> {
     mark_running(pool, event_id, "zip").await;
@@ -126,7 +129,8 @@ async fn run_zip_export(
     let uploads = query_uploads(pool, event_id).await?;
     let total = uploads.len().max(1) as f32;
 
-    let exports_dir = media_path.join("exports");
+    // Written OUTSIDE media_path: the public /media ServeDir must never reach these.
+    let exports_dir = export_path.to_path_buf();
     tokio::fs::create_dir_all(&exports_dir).await?;
 
     let tmp_path = exports_dir.join("Gallery.zip.tmp");
@@ -193,6 +197,7 @@ async fn run_html_export(
     event_name: &str,
     pool: &PgPool,
     media_path: &Path,
+    export_path: &Path,
     sse_tx: &broadcast::Sender<SseEvent>,
 ) -> Result<()> {
     mark_running(pool, event_id, "html").await;
@@ -205,7 +210,8 @@ async fn run_html_export(
 
     update_progress(pool, event_id, "html", 5).await;
 
-    let exports_dir = media_path.join("exports");
+    // Written OUTSIDE media_path: the public /media ServeDir must never reach these.
+    let exports_dir = export_path.to_path_buf();
     tokio::fs::create_dir_all(&exports_dir).await?;
 
     // 2. Create temp directory for media processing

docker-compose.yml

@@ -34,6 +34,9 @@ services:
         condition: service_healthy
     volumes:
       - media_data:/media
+      # Export archives live OUTSIDE /media so the public media ServeDir can't
+      # serve them — downloads go only through the ticket-gated handler.
+      - exports_data:/exports
     expose:
       - "3000"
     healthcheck:
@@ -96,4 +99,5 @@ services:
 volumes:
   postgres_data:
   media_data:
+  exports_data:
   caddy_data:

e2e/specs/03-feed/comment-ui.spec.ts

@@ -0,0 +1,53 @@
+/**
+ * Regression for the review's CR1: the LightboxModal posted comments to
+ * `/upload/{id}/comment` (singular) while the only route is `/comments` (plural),
+ * so every comment submitted through the UI 404'd and was silently lost. The
+ * earlier "comment → SSE" spec passed by posting via a fetch helper, bypassing
+ * the component — a false green. This drives the real component end-to-end.
+ */
+import { test, expect } from '../../fixtures/test';
+import { seedUpload } from '../../helpers/seed';
+
+const BASE = process.env.E2E_FRONTEND_URL ?? 'http://localhost:3101';
+
+test.describe('Comments — UI round-trip (CR1)', () => {
+  test('a comment typed in the lightbox persists to the backend', async ({
+    page,
+    guest,
+    signIn,
+  }) => {
+    const author = await guest('CommentAuthor');
+    const commenter = await guest('Commenter');
+    const uploadId = await seedUpload(author.jwt, { caption: 'Comment target' });
+
+    await signIn(page, commenter);
+    await page.goto('/feed');
+
+    // Open the lightbox. Only one upload exists, so the first open-button is it.
+    const imageButton = page.getByRole('button', { name: 'Bild vergrößern' }).first();
+    await expect(imageButton).toBeVisible({ timeout: 15_000 });
+    await imageButton.click();
+
+    const lightbox = page.locator('[role="dialog"][aria-labelledby="lightbox-title"]');
+    await expect(lightbox).toBeVisible();
+
+    const text = `Wunderschönes Foto ${Date.now()}`;
+    await lightbox.getByPlaceholder(/kommentar/i).fill(text);
+    await lightbox.getByRole('button', { name: /senden/i }).click();
+
+    // The component appends the comment only on a 2xx — with the old singular path
+    // it threw and nothing appeared. Assert it's visible in the panel...
+    await expect(lightbox.getByText(text)).toBeVisible();
+
+    // ...and that it actually persisted server-side (the crux CR1 broke).
+    await expect
+      .poll(async () => {
+        const res = await fetch(`${BASE}/api/v1/upload/${uploadId}/comments`, {
+          headers: { Authorization: `Bearer ${commenter.jwt}` },
+        });
+        const body = await res.json();
+        return Array.isArray(body) && body.some((c: { body: string }) => c.body === text);
+      })
+      .toBe(true);
+  });
+});

e2e/specs/06-export/export-leak.spec.ts

@@ -0,0 +1,22 @@
+/**
+ * Regression for the review's CR2: export archives (Gallery.zip / Memories.zip)
+ * were written under media_path/exports, and /media is a public ServeDir — so
+ * anyone could GET /media/exports/Gallery.zip and download the whole gallery,
+ * bypassing the ticket + export_*_ready gate. Exports now live OUTSIDE media_path
+ * and are reachable only via the gated /api/v1/export/{zip,html} handlers (covered
+ * by export.spec.ts). Here we assert the public path is dead.
+ */
+import { test, expect } from '../../fixtures/test';
+
+const BASE = process.env.E2E_FRONTEND_URL ?? 'http://localhost:3101';
+
+test.describe('Export — no public leak (CR2)', () => {
+  test('archives are not reachable through the public /media path', async () => {
+    for (const name of ['Gallery.zip', 'Memories.zip']) {
+      const res = await fetch(`${BASE}/media/exports/${name}`);
+      // 404 (not 200): a 200 here would mean the whole-gallery archive is
+      // downloadable without any auth — the CR2 data-exposure regression.
+      expect(res.status).toBe(404);
+    }
+  });
+});

frontend/src/lib/components/LightboxModal.svelte

@@ -2,6 +2,7 @@
 	import { onDestroy } from 'svelte';
 	import type { FeedUpload } from '$lib/types';
 	import { api } from '$lib/api';
+	import { onSseEvent } from '$lib/sse';
 	import { getUserId } from '$lib/auth';
 	import { dataMode, pickMediaUrl } from '$lib/data-mode-store';
 	import { doubletap } from '$lib/actions/doubletap';
@@ -48,8 +49,18 @@
 		burstTimer = setTimeout(() => (heartBurst = false), 700);
 	}
 
+	// Drop a comment live when it's deleted elsewhere (host moderation or the
+	// author on another device), so the open panel doesn't show a ghost comment.
+	const unsubCommentDeleted = onSseEvent('comment-deleted', (data) => {
+		try {
+			const { comment_id } = JSON.parse(data) as { comment_id: string };
+			comments = comments.filter((c) => c.id !== comment_id);
+		} catch { /* ignore */ }
+	});
+
 	onDestroy(() => {
 		if (burstTimer) clearTimeout(burstTimer);
+		unsubCommentDeleted();
 	});
 
 	// Only refetch when a *different* upload is shown. The feed reassigns the
@@ -74,7 +85,7 @@
 		if (!newComment.trim()) return;
 		loading = true;
 		try {
-			const comment = await api.post<CommentDto>(`/upload/${upload.id}/comment`, {
+			const comment = await api.post<CommentDto>(`/upload/${upload.id}/comments`, {
 				body: newComment.trim()
 			});
 			comments = [...comments, comment];