fix: fall back to Bunny Storage for cover images

server/src/providers/bunny-storage.ts

@@ -52,3 +52,18 @@ export async function uploadBunnyCover(image: CoverImage) {
   }
   return { key, coverImageUrl: `${cdnHost}/${key}` };
 }
+
+export async function downloadBunnyCover(filename: string) {
+  const { zone, password, endpoint } = bunnyStorageConfiguration();
+  const response = await fetch(`${endpoint}/${encodeURIComponent(zone)}/covers/${encodeURIComponent(filename)}`, {
+    headers: { AccessKey: password },
+  });
+  if (!response.ok) {
+    const detail = await response.text().catch(() => '');
+    throw new BunnyStorageRequestError(`Bunny Storage download failed (${response.status})${detail ? `: ${detail.slice(0, 250)}` : ''}`);
+  }
+  return {
+    body: Buffer.from(await response.arrayBuffer()),
+    contentType: response.headers.get('content-type') || 'application/octet-stream',
+  };
+}

server/src/routes/courses.ts

@@ -2,6 +2,7 @@ import type { FastifyPluginAsync } from 'fastify';
 import { z } from 'zod';
 import { pool } from '../db/pool.js';
 import { signedBunnyEmbedUrl, BunnyConfigurationError } from '../providers/bunny.js';
+import { BunnyStorageConfigurationError, BunnyStorageRequestError, downloadBunnyCover } from '../providers/bunny-storage.js';
 
 const paramsSchema = z.object({
   courseId: z.string().uuid(),
@@ -10,6 +11,9 @@ const playbackParamsSchema = z.object({
   courseId: z.string().uuid(),
   lessonId: z.string().uuid(),
 });
+const coverParamsSchema = z.object({
+  filename: z.string().regex(/^[0-9a-f]{8}-[0-9a-f-]{27}\.(?:jpg|png|webp)$/i),
+});
 
 export const courseSelect = (publicOnly = false, includeUnreadyMedia = false) => `
   select
@@ -110,6 +114,21 @@ export const courseRoutes: FastifyPluginAsync = async (app) => {
     return { data: result.rows.map((row) => row.name) };
   });
 
+  app.get('/covers/:filename', async (request, reply) => {
+    const { filename } = coverParamsSchema.parse(request.params);
+    try {
+      const cover = await downloadBunnyCover(filename);
+      reply.header('Content-Type', cover.contentType);
+      reply.header('Cache-Control', 'public, max-age=86400, stale-while-revalidate=604800');
+      return reply.send(cover.body);
+    } catch (error) {
+      if (error instanceof BunnyStorageConfigurationError || error instanceof BunnyStorageRequestError) {
+        return reply.code(404).send({ error: 'Cover image was not found' });
+      }
+      throw error;
+    }
+  });
+
   app.get('/', async (request) => {
     const authenticated = await hasSession(request);
     const result = await pool.query(