meta-feeder-indexer proxies an external Newznab indexer and mints an nzb-release (0x1005) cid that embeds that indexer's host. Only a peer holding that indexer's credential can ever redeem it — so the metadata half of Usenet is neither self-owned nor portable.

Scanning Usenet ourselves gives us the article Message-IDs for free at collation time (no grab, no scrape). That lets this feeder mint a portable nzb-posting (0x1003) cid — a digest over the Message-ID set, embedding no host — which any peer with a plain NNTP provider can redeem, with no indexer credential anywhere in the path.

This feeder adds a Usenet metadata source alongside meta-feeder-indexer. It replaces nothing; a gateway query fans out to both.

Design record: meta-gateway/docs/others/self-hosted-usenet-indexer-study.md.

Shape

[nntmux sidecar: PHP + MariaDB + Redis]     [usenet-feeder: Rust, FeederPlugin]
  header-scan groups (few conns)   ──►  reads `releases` (searchname/size/guid)
  collate → releases               ──►  gunzips <nzb_root>/<c>/<guid>.nzb.gz
  writes <guid>.nzb.gz             ──►  mints 0x1003 from the Message-ID set
  (CBP purged; the gz is the only  ──►  emits the record + a relative
   durable home of the msg-ids)          `manifest_url` onto its own /blob route
                                                    │
                                                    ▼
   gateway core: seeds the .nzb as an ORDINARY sha2-256 IPFS cid, publishes it
   as a fileType=nzb meta-core record, rewrites the field to that cid
   (the same path posters take — `remote_feeder.rs` SEEDABLE_FIELDS)
                                                    │
                                                    ▼
   meta-share: resolve `manifest` cid (blockstore / bitswap / ANY holder) →
   NzbManifest::from_nzb_xml → BODY-fetch each Message-ID from ANY plain NNTP
   provider → materialise → play

The sidecar is persistent cache, cheap to lose — everything in it is re-derivable by re-scanning. Same pattern as the Tribler sidecar: stateful upstream, but the gateway still sees a stateless HTTP feeder.

Like every feeder this one is meta-core-free and blockstore-free: it finds records and serves bytes; the core owns hashing-into-the-blockstore, the meta-core store-back, and the libp2p wire (gateway invariant 10).

Configuration

Operator config lives on the feeder, not the gateway (invariant 12). Set it on the plugin's config page in the gateway dashboard; the env vars below are a first-boot seed only — the persisted config.json wins on the next restart, and there is no hot reload.

Field	Env seed	What
`db_url`	`NNTMUX_DB_URL`	MariaDB DSN of nntmux's catalog, e.g. `mysql://nntmux:secret@nntmux-db:3306/nntmux`. Blank → the upstream soft-skips and the plugin reports Degraded.
`nzb_root`	`NNTMUX_NZB_PATH`	nntmux's NZB directory as mounted into this container. Must be the same volume nntmux's `PATH_TO_NZBS` points at, or every release resolves to `NotFound`.

Infra env: META_FEEDER_HTTP_LISTEN (default 0.0.0.0:8080), META_FEEDER_STATE_DIR (default /data/meta-feeder), RUST_LOG.

Scan policy — which groups, backfill depth, scan interval, connection budget — is the gateway maintainer's call and is configured on the nntmux sidecar. Keep the connection budget conservative: the scanner and playback draw on the same provider slots, so a greedy value does not merely over-scan, it stalls playback mid-stream.

Build

cargo build --release --bin usenet-feeder
cargo test --workspace
cargo clippy --workspace --all-targets -- -D warnings

docker build -f feeder-plugin/usenet-feeder/Dockerfile -t ghcr.io/worph/meta-feeder-usenet:dev .

crates/meta-feeder-sdk/ is a vendored copy of the SDK, mirrored from meta-gateway. Independent submodules cannot share a cargo path-dep, so keep it in step when the SDK changes — in particular hash.rs's compute_nzb_posting_cid, whose normalisation rule is the dedup contract and is mirrored again on the meta-share side.

Gotchas

An empty catalog is the visible symptom of both nntmux silent-zero traps: an empty PATH_TO_NZBS (set-but-empty beats the default, so createNZBs() aborts and you get 0 releases with no error), and seeded groups left active=0. The plugin logs a loud warning when releases is empty at boot — believe it.
The Message-IDs are not in the database. nntmux purges collections/binaries/parts right after writing each NZB, so the on-disk .nzb.gz is the only durable home. A wrong nzb_root therefore fails at compute_outcomes, not at query time.