update non-challenge video thumbnails + automation script

Author: fturmel

content/videos/code/0-trailer/trailer/index.jpg

@@ -0,0 +1,61 @@
+import { paths } from '../content-testing/content.js';
+import path from 'node:path';
+import fs from 'node:fs';
+
+// Thumbnails for non-challenge videos can just use the YouTube thumbnail.
+// They are never displayed on the site directly, only when sharing links on social media.
+
+function sleep(ms) {
+  return new Promise((resolve) => setTimeout(resolve, ms));
+}
+
+async function getImage(url) {
+  const response = await fetch(url);
+
+  if (!response.ok) return;
+
+  const arrayBuffer = await response.arrayBuffer();
+  return Buffer.from(arrayBuffer);
+}
+
+console.log(`Downloading ${paths.videos.length} thumbnails`);
+
+for (const jsonPath of paths.videos) {
+  const baseDir = path.join(path.dirname(jsonPath));
+
+  // remove existing thumnails (co-located with index.json files if they exist)
+  ['index.jpg', 'index.png'].forEach((filename) => {
+    fs.rmSync(path.join(baseDir, filename), { force: true });
+  });
+
+  const { videoId } = JSON.parse(fs.readFileSync(jsonPath));
+
+  console.log(videoId);
+
+  // download thumbnail from YouTube CDN
+  const thumbnailPaths = [
+    `https://img.youtube.com/vi/${videoId}/maxresdefault.jpg`, // highest resolution (might not be available for 720p videos)
+    `https://img.youtube.com/vi/${videoId}/hqdefault.jpg` // fallback
+  ];
+
+  let buffer;
+  for (const thumbnailPath of thumbnailPaths) {
+    buffer = await getImage(thumbnailPath);
+    if (buffer) break;
+
+    console.warn(`Failed to download ${thumbnailPath}`);
+  }
+
+  if (!buffer) {
+    console.error(
+      `Failed to locate a thumbnail for ${videoId} - process aborted.`
+    );
+    process.exit(1);
+  }
+
+  // write file to disk
+  fs.writeFileSync(path.join(baseDir, 'index.jpg'), buffer);
+
+  // sleep for a bit to avoid spamming / getting blocked
+  await sleep(100 + Math.random() * 500);
+}