Blossom Content-Addressed URL Filtering

Problem

Code that extracts video URLs from Nostr events (or similar tag-based metadata) silently drops URLs from Blossom servers and other content-addressed storage because it filters on file extensions like .mp4. These servers use hash-based URLs without extensions (e.g. https://blossom.example.com/{sha256}), causing the URL extraction to fail and fall back to a CDN URL that also 404s for non-CDN content.

Context / Trigger Conditions

• Videos from certain servers are never processed (moderated, transcoded, etc.)
• URL extraction code contains patterns like url.includes('.mp4') or url.includes('/video/')
• Nostr imeta tag URL extraction requires .mp4 in the URL string
• Nostr r tag filtering checks for .mp4 or /video/ in the URL
• CDN fallback constructs https://cdn.domain/{sha256}.mp4 but server serves at /{sha256}
• Content-addressed storage (Blossom, IPFS gateways) uses extensionless URLs
• Failures are silent — no errors, videos just never appear in the processing pipeline

Solution

1. Remove extension filtering from URL extraction

Bad (drops blossom URLs):

// imeta tag extraction
if (param.startsWith('url ') && param.includes('.mp4')) {
  url = param.substring(4).trim();
}

// r tag extraction
if (url.includes('.mp4') || url.includes('/video/')) {
  return url;
}

Good (accepts any URL):

// imeta tag extraction — accept any URL
if (param.startsWith('url ') && param.length > 4) {
  url = param.substring(4).trim();
}

// r tag extraction — accept any http URL
if (url.startsWith('http')) {
  return url;
}

2. For kind-specific events, trust the event kind

If you already know an event is a video event (e.g. kind 34236), any URL in its tags is a video URL. Don't re-validate the media type by extension.

3. Use mime type from imeta instead of extension

If you need to validate media type, use the m field in imeta tags:

for (const param of tag.slice(1)) {
  if (param.startsWith('m video/')) isVideo = true;
  if (param.startsWith('url ')) imetaUrl = param.substring(4).trim();
}

4. Fix CDN fallback URLs

// Bad: appends .mp4
let videoUrl = `https://${CDN_DOMAIN}/${sha256}.mp4`;

// Good: content-addressed path (no extension)
let videoUrl = `https://${CDN_DOMAIN}/${sha256}`;

Verification

• Check that videos from non-CDN blossom servers appear in the moderation/processing queue
• Verify that extractVideoUrlFromEvent returns URLs for events with extensionless imeta/r tags
• Confirm CDN fallback URLs resolve correctly without .mp4 extension

Example

A Nostr kind 34236 event with tags:

["imeta", "url https://blossom.primal.net/abc123def456...", "m video/mp4", "x abc123def456..."]

Old code: url.includes('.mp4') → false → URL dropped → CDN fallback → 404 → video never moderated

New code: accepts any URL from imeta → https://blossom.primal.net/abc123def456... → HiveAI can fetch it → video moderated

Notes

• This applies to ANY media processing pipeline, not just moderation
• Blossom (BUD-01) uses /{sha256} paths; some servers add Content-Type headers
• HLS streams (.m3u8), WebP thumbnails, and other formats also won't have .mp4 extensions
• Some rogue clients may not follow any path convention at all
• The m (mime type) field in imeta is the proper way to determine media type, not the URL path
• Prioritize imeta URLs over r tag URLs (imeta is more specific/reliable)