- A public post that links to a page gets a preview card: from the post's own data first (FEP-8967 Link preview, the
object's image, title and summary); otherwise the server reads the page once, 0-60 s after the post arrives, never
when someone reads it. OpenGraph and Twitter tags give title, description and image; one LinkPreview per address
is cached for 7 days and shared by the whole server, so a fetch never points at a persona.
- Lemmy link posts, which carry no title or description, get them filled in.
- The page fetch uses the guarded client (public addresses, three redirects, HTML only, first 512 KB).
- Federation:FetchLinkPreviews switches page fetching off.
- Local public posts get cards too.
Checked live: a link to a GoToSocial profile page becomes a card with its title, description and proxied image.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_012CzABvBkbcFqoHdmi8b9WB
- When a sender's key cannot be fetched because its server timed out or answered 5xx, the inbox answers 503 with
Retry-After: 300 instead of 401, so Mastodon 4.7 retries rather than switching to RFC 9421 signatures we do not
verify yet. The fetcher's failure cache now remembers whether a failure was temporary.
- Follow, Like, Block, Accept, Reject and Undo ids are deliberately not dereferenceable: serving them would publish
who follows, likes and blocks whom. They are always sent with their object embedded.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_012CzABvBkbcFqoHdmi8b9WB
- /api/v1/media and /api/v2/media (and GET/PUT /api/v1/media/:id):
images go through libvips (NetVips, its native build bundled):
autorotated, every kind of metadata dropped (EXIF, GPS, XMP, IPTC,
comments), capped at 4096 px, with a 640 px preview and a blurhash
(own encoder, the reference algorithm); animated GIFs are re-encoded;
video and audio are remuxed by ffmpeg with -map_metadata -1, never
re-encoded, and a video gets a still preview. Files get random names
under /var/lib/privapub/media, outside the web root deploys replace, and
are served at /media/files with nosniff and a sandbox CSP.
- media_ids on create and edit (four at most, the persona's own, each used
once); notes carry them as Document attachments with alt text, blurhash,
focalPoint and size; inbound attachments were already kept.
- avatar and header uploads in update_credentials, cropped to 400x400 and
1500x500, federated with Update{Person}.
- Remote media reaches clients only through /media/proxy/{hmac}/{url},
fetched by the guarded client (no SVG, 40 MB cap) and cached outside the
served root, trimmed to 5 GB; foreign avatars and headers use it too, so
a client never contacts another server.
- MediaJanitor deletes uploads left unattached for a day.
- nginx accepts 100 MB bodies on the upload endpoints only (applied on Max).
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_012CzABvBkbcFqoHdmi8b9WB
DomainBlock (domain, severity, reject-media, public and private comment)
covers the domain and its subdomains. Admins manage them under
/clientapi/admin/domainblocks/{list,insert,delete}; the set is kept in
memory, reloaded on every change and at most five minutes stale.
A suspended domain is refused by FederationHttp.IsAllowed, so nothing is
fetched from it and no job delivers to it, and the inbox drops its
activities with a 202 before fetching any key. Reject-media strips the
attachments of posts from that domain. Silence is recorded for the
timelines and notifications that arrive in P1.2.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_012CzABvBkbcFqoHdmi8b9WB
Infrastructure/Http adds the client the roadmap's S3 and S4 ask for:
- the connect callback resolves the name itself and refuses loopback,
private, link-local, CGNAT, documentation, multicast, ULA, NAT64, 6to4,
Teredo and IPv4-mapped/compatible forms, then connects to the vetted
address, so DNS rebinding cannot swap it afterwards;
- redirects are followed by hand, at most three, each one re-checked;
- bodies are capped at 1 MB after decompression, only JSON media types are
read, every request has a 15 s budget, and a refused URL is not asked
again for five minutes.
Actor and WebFinger fetches and inbox deliveries all use it. Test networks
can switch on Federation:AllowPrivateNetworks/AllowPlainHttp; startup
refuses both in Production.
PrivaPub.Tests (xUnit v3) starts with the address table and the fetcher's
limits against an in-process peer; build.yml and deploy.yml run it.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_012CzABvBkbcFqoHdmi8b9WB
thepraandClaude Opus 5.5