Nostr relay: add size limits (and optional write auth and persistence), in line with strfry and others #648
Description
The built-in Nostr relay (--nostr) has no size limits of its own. It's barely used beyond one pod so far, so this isn't urgent, but it's worth matching what other relays do before anyone leans on it.
What JSS does now (at 2b9555b)
- src/server.js:417 registers @fastify/websocket with no options, so ws uses its default maxPayload of 100 MB per message.
- src/nostr/relay.js checks no event size, keeps up to 1,000 events in memory only (DEFAULT_MAX_EVENTS, lost on restart), allows anyone to write, and rate-limits to 60 events per minute per connection.
So a client can send very large events, and a handful of them can use a lot of memory.
What other relays default to
| Relay | Max event | Max websocket message | Other defaults |
|---|---|---|---|
| strfry | 64 KB (maxEventSize) | 128 KB (maxWebsocketPayloadSize) | ≤ 2,000 tags, tag values ≤ 1 KB, created_at window (15 min ahead, 3 years back), write-policy plugin, LMDB on disk |
| nostr-rs-relay | 128 KB | 128 KB | kind allow/block lists, pubkey allowlist, NIP-42, SQLite/Postgres |
| khatru | — | 500 KB (MaxMessageSize) | policies as plug-in functions |
| nostream | 100 KB content per kind range | 512 KB (maxPayloadSize) | per-kind limits, rate limits, Postgres |
| JSS | none | 100 MB | 60 events/min/connection, 1,000 in memory, open writes |
Suggested defaults
- Websocket message cap of 128 KB for the relay (configurable).
- Event size cap of 64 KB (configurable), like strfry.
- Tag limits: at most 2,000 tags, tag values at most 1 KB.
- created_at window, like strfry's.
- Optional write allowlist (e.g. only the pod owner's key) or NIP-42 auth, off by default.
- Optional persistence to disk under the pod, for events meant to last.
1–4 close the size issue; 5–6 make the relay usable for real data (for example, publishing mind maps as Nostr events, which are 4–5 KB each).
Sources: strfry.conf, nostr-rs-relay config.toml and config.rs, khatru relay.go, nostream default-settings.yaml.
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