nostr-pubsub

Neutral Nostr event and source routing primitives for relay, mesh, local-index, and test backends.

This crate re-exports standard nostr protocol message types for normal REQ/CLOSE subscriptions and EVENT delivery. It adds transport-neutral building blocks for:

• bounded event retention policies based on Nostr filters
• source routes and priority-aware routed queries
• inv/want content keys, inventory announcements, wants, and frames
• a bounded signed-event InvWantMesh state machine with reverse wants, exactly-once local delivery, and configurable protocol envelopes
• targeted cached-event replay for late peers through the same inventory/WANT/frame proof
• priority-aware peer fanout with explicit unknown-peer exploration capacity
• peer subscription tracking so inventory is sent only after a matching filter
• bounded FIPS payload-frame codecs for standard Nostr REQ/CLOSE/EVENT

VerifiedEvent verifies both the event ID and Schnorr signature. The FIPS wire adapter updates bounded peer subscriptions and never returns an unverified event. FIPS transports remain responsible for stream framing, admission, liveness, and backpressure.

Product crates keep their own app-specific event meanings. This crate provides the shared pubsub vocabulary. Peer-quality inputs are local transport or pubsub observations; the mesh does not assume that a transport peer has a social identity and does not trust shared ratings by default.

The production mesh's local score is provider-specific. It rewards a peer only after an accepted inventory is wanted and the peer returns the matching valid signed frame. Inventories outside the configured kind subscription, invalid or mismatched frames, and accepted inventories left unserved through route expiry are negative evidence. Silent peers remain unknown. Applications should run author/social admission before delivering a frame to the mesh; a locally rejected valid frame can be dismissed without provider credit or penalty.

Consumers select exactly one PubsubProvider: local-only for a local peer provider or direct-relay for direct relay sockets. Provider construction is explicit and the core never falls back between the two modes at runtime.