Resumable Upload with Range Reconciliation

For large uploads, stream data in 256KB-aligned chunks and trust YouTube's Range header as the source of truth.

Required Behavior

• Chunk size: multiples of 256KB (except final chunk).
• Send Content-Range: bytes start-end/total for each PUT.
• Handle responses:
  • 201: upload complete, parse video resource ID.
  • 308: incomplete, parse Range: bytes=0-XXXX and continue from XXXX + 1.

Critical Rule

Never assume a full chunk was accepted. Use returned Range when present.

const range = response.headers.get('Range');
if (range) {
  const match = range.match(/bytes=0-(\d+)/);
  bytesUploaded = match ? Number(match[1]) + 1 : bytesUploaded + chunk.length;
}

Streaming Pattern

• Read from ReadableStream.
• Buffer until threshold (or final chunk).
• Upload chunk.
• Reset buffer and continue.

Thumbnail Follow-up

After main upload, upload thumbnail separately:

• hard cap 2MB
• fallback resize/quality ladder (e.g. 1280x720@95 -> smaller/lower quality)
• treat thumbnail failure as non-fatal if main video succeeded