rework plugin

.gitattributes

@@ -0,0 +1,6 @@
+# FIX CRLF always when developer has not set
+# Linux/Mac: git config --global core.autocrlf input
+# Windows: git config --global core.autocrlf true
+# Auto detect text files and perform LF normalization
+* text=auto
+* eol=lf

.gitignore

@@ -0,0 +1,3 @@
+/target
+Cargo.lock
+.cargo/config.toml

Cargo.toml

@@ -0,0 +1,63 @@
+[package]
+name = "meta-feeder-sdk"
+version = "0.1.0"
+edition = "2021"
+rust-version = "1.85"
+license = "MIT"
+repository = "https://github.com/worph/meta-feeder-sdk"
+description = "Source-agnostic foundation for MetaMesh gateway feeders: the FeederPlugin trait, the content-addressing hash families, the structured-query evaluator, and an axum harness that serves any set of plugins over the feeder HTTP contract."
+readme = "README.md"
+keywords = ["metamesh", "feeder", "gateway", "content-addressing", "plugin"]
+categories = ["api-bindings", "web-programming::http-server"]
+
+# Not on crates.io yet — consumers depend on a git tag while the contract is
+# still moving (see docs/project-architecture/feeder-architecture.md §8).
+# Flip this, not the dep form, when `cargo add meta-feeder-sdk` should work.
+publish = false
+
+# This repo IS the crate. The explicit (empty) workspace table stops it being
+# absorbed into a parent workspace when it is vendored or path-overridden into
+# a feeder checkout during local development.
+[workspace]
+
+# Source-agnostic foundation shared by the gateway core and every feeder
+# sidecar binary: the `FeederPlugin` trait, the content-addressing hash
+# families, the per-plugin redb cache, the shared HTTP/cache helpers, the
+# structured-query evaluator, and the axum `serve_feeders` harness that wraps
+# any set of `FeederPlugin`s in the feeder HTTP contract.
+#
+# Deliberately libp2p-free / blockstore-free: a feeder finds + fetches bytes;
+# the gateway core owns hashing-into-the-blockstore, the meta-core store-back,
+# and the libp2p wire. Keep heavy deps (librqbit, beetswap, cid, libp2p) OUT
+# of here so feeders that don't need them don't pay for them.
+
+[dependencies]
+# Async runtime + HTTP server (the serve_feeders harness)
+tokio = { version = "1.40", features = ["full"] }
+axum = { version = "0.7", features = ["json"] }
+hyper = { version = "1", features = ["full"] }
+reqwest = { version = "0.12", features = ["json", "rustls-tls", "stream"], default-features = false }
+
+# Serialization
+serde = { version = "1", features = ["derive"] }
+serde_json = "1"
+base64 = "0.22"
+
+# Utilities
+futures = "0.3"
+async-trait = "0.1"
+anyhow = "1"
+thiserror = "1"
+tracing = "0.1"
+sha2 = "0.10"
+bytes = "1"
+# Title-tag parsing (shared filename_meta — season/episode/quality/codec/languages).
+regex = "1"
+
+# Per-plugin midhash/blob cache. Schema is identical to meta-share v1 — see
+# cache.rs. Pure-Rust single-process embedded store.
+redb = "2"
+
+[dev-dependencies]
+tempfile = "3"
+tokio = { version = "1.40", features = ["full", "test-util"] }

README.md

@@ -1 +1,138 @@
 # meta-feeder-sdk
+
+The source-agnostic foundation shared by the MetaMesh gateway core and every
+feeder sidecar.
+
+A **feeder** bridges one external source into the MetaMesh network. It
+implements [`FeederPlugin`](src/plugin.rs) — find records, resolve them to
+content-addressed outcomes, optionally fetch bytes — and `serve_feeders` exposes
+any set of plugins over the feeder HTTP contract. The gateway core consumes that
+contract and keeps the libp2p wire, the bitswap blockstore, the
+hashing-into-the-blockstore and the meta-core store-back to itself.
+
+Deliberately **libp2p-free and blockstore-free**: a feeder finds and fetches
+bytes; it never joins the swarm.
+
+## Using it
+
+```toml
+[dependencies]
+meta-feeder-sdk = { git = "https://github.com/worph/meta-feeder-sdk", tag = "v0.1.0" }
+```
+
+Not on crates.io yet — the contract is still moving, so consumers pin a tag.
+
+```rust
+use meta_feeder_sdk::{serve_feeders, FeederPlugin};
+
+#[tokio::main]
+async fn main() -> anyhow::Result<()> {
+    let plugins: Vec<Box<dyn FeederPlugin>> = vec![Box::new(MyPlugin::new())];
+    serve_feeders(plugins, "/data/meta-feeder".into(), "0.0.0.0:8080".parse()?).await
+}
+```
+
+A **service is a `Vec`** — grouping plugins into one binary is a deployment
+choice, not an architectural one.
+
+## Writing a plugin
+
+Four required methods; everything else has a default:
+
+| method | you must | notes |
+|---|---|---|
+| `upstream_id` | return a stable `&'static str` | identifies your records |
+| `configure` | set up a cache dir; return `MissingConfig` if unconfigured | the harness soft-skips a plugin that returns `MissingConfig`, so an unconfigured plugin degrades instead of killing the sidecar |
+| `handle_query` | answer a `GatewayQuery` with `DiscoveryRecord`s | **open with `query_eval::query_accepts_plugin`** — see below |
+| `compute_outcomes` | resolve a `record_id` to `HashOutcome`s | `bytes: None` for metadata-only sources |
+
+Defaults you can override: `handle_query_stream`, `handle_fetch`, `health`,
+`served_file_types`, `served_content_kinds`, `config_schema`, `config_values`,
+`get_blob`.
+
+### The routing gate
+
+The gateway dispatches on `(fileType, contentKind)`, never on a service name.
+Advertise your axes and gate on them, or you will be handed queries you cannot
+answer:
+
+```rust
+fn served_file_types(&self)    -> &'static [&'static str] { &["video"] }
+fn served_content_kinds(&self) -> &'static [&'static str] { &["movie", "series"] }
+
+async fn handle_query(&self, q: &GatewayQuery, n: usize) -> Result<Vec<DiscoveryRecord>, GatewayError> {
+    if !meta_feeder_sdk::query_eval::query_accepts_plugin(
+        q, self.served_file_types(), self.served_content_kinds()) {
+        return Ok(Vec::new());
+    }
+    // ...
+}
+```
+
+`&["*"]` on an axis means "I serve every value on it".
+
+### Three rules that are not obvious
+
+1. **Records must carry a type filter.** A record with no `fileType` /
+   `contentKind` never reaches a client wall, and the symptom looks like a
+   transport bug rather than a metadata one.
+2. **`filters` / `ranges` / `negations` are authoritative; `raw_text` is
+   informational.** Consume one source per filter or you will double-filter and
+   under-match.
+3. **Never degrade an unresolvable anchor into a free-text query.**
+   `free_text_or_star()` exists for upstreams that 4xx on empty input — reaching
+   for it when an *identity* filter failed to resolve dumps the upstream's
+   recent feed into someone's library.
+
+## Hash families
+
+`HashKind` selects how the core routes an outcome. Only `Sha2_256` is seeded
+into the bitswap blockstore.
+
+| kind | codec | means |
+|---|---|---|
+| `Sha2_256` | standard | real bytes, retrievable via bitswap |
+| `Midhash256` | `0x1000` | size + middle-sample; MetaMesh-internal |
+| `BtV1File` | `0x1001` | a file inside a torrent — locator |
+| `NzbRelease` | `0x1005` | a Usenet release — locator, redeemed by a credentialed peer |
+| `CardLocator` | `0x1007` | a *work*, no bytes anywhere |
+| `YtVideo` | `0x1008` | **delegated playback** — bytes are permanently someone else's |
+
+The last two carry an identity multihash. Anything that dispatches on the
+multihash instead of the **codec** will silently mis-rank them.
+
+## Layout
+
+| module | what |
+|---|---|
+| `plugin` | the `FeederPlugin` trait, `HashKind`, `HashOutcome`, `ConfigError` |
+| `types` | `DiscoveryRecord`, `GatewayError`, `PluginHealth`, `ByteStream` |
+| `query` / `query_eval` | the structured query and its evaluator |
+| `serve` | the axum harness and the HTTP contract DTOs |
+| `config` | self-describing config schema — the dashboard renders a form from it |
+| `cache` | per-plugin redb cache |
+| `hash` | the content-addressing families above |
+| `filename_meta` / `lang` | release-tag parsing helpers |
+| `enrich`, `meta_core`, `common` | MetaMesh-internal; not part of the plugin contract |
+
+## Development
+
+```bash
+cargo build && cargo test
+```
+
+To work on the SDK from inside a feeder checkout without pushing a tag, add a
+gitignored `.cargo/config.toml` in the feeder:
+
+```toml
+paths = ["../meta-feeder-sdk"]
+```
+
+## Context
+
+Design rationale, the feeder roster, and the naming rules live in the meta-root:
+`docs/project-architecture/feeder-architecture.md`.
+
+## License
+
+MIT

rust-toolchain.toml

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+[toolchain]
+channel = "1.89"
+components = ["rustfmt", "clippy"]

src/cache.rs

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+//! Per-plugin midhash cache backed by redb.
+//!
+//! Each plugin gets its own redb file at
+//! `<state_dir>/gateway/<upstream_id>/cache.redb`. Keys are upstream
+//! `record_id`s (DOI for sci-hub, book id for gutenberg, …); values are the
+//! `Midhash` strings the plugin computed by fetching + hashing the upstream
+//! file.
+//!
+//! The schema is identical to meta-share v1's so old `.redb` files copy
+//! across. redb is synchronous and sub-millisecond for small ops, so calls
+//! run inline from async handlers without `spawn_blocking`.
+
+use std::path::Path;
+use std::sync::Arc;
+
+use redb::{Database, ReadableTableMetadata, TableDefinition};
+
+pub const CACHE_FILENAME: &str = "cache.redb";
+
+const MIDHASH_TABLE: TableDefinition<'_, &str, &str> = TableDefinition::new("midhash");
+const BLOBS_TABLE: TableDefinition<'_, &str, &[u8]> = TableDefinition::new("blobs");
+const COVER_CID_TABLE: TableDefinition<'_, &str, &str> = TableDefinition::new("cover_cid");
+const BIBREC_TABLE: TableDefinition<'_, &str, &str> = TableDefinition::new("bibrec");
+const PREVIEW_CID_TABLE: TableDefinition<'_, &str, &str> = TableDefinition::new("preview_cid");
+/// Full-file sha2-256 IPFS cid for a previously-fetched torrent payload
+/// (torznab's bt-fetch path). Distinct from `MIDHASH_TABLE` because the
+/// hash families differ: `midhash` is the synthetic midhash256-from-infohash
+/// fallback; `fullhash` records "we actually downloaded the bytes and this is
+/// the IPFS CIDv1 over them."
+const FULLHASH_TABLE: TableDefinition<'_, &str, &str> = TableDefinition::new("fullhash");
+/// Enumerated torrent file list (JSON `Vec<TorrentFile>`) keyed by the
+/// torrent's `record_id` (infohash).
+const FILELIST_TABLE: TableDefinition<'_, &str, &str> = TableDefinition::new("filelist");
+/// Cached TMDB *search* results keyed by a stable lookup key. The value is the
+/// JSON encoding of the top `TmdbHit`, or the literal `"null"` negative-cache
+/// sentinel.
+const TMDB_SEARCH_TABLE: TableDefinition<'_, &str, &str> = TableDefinition::new("tmdb_search");
+/// Cached TMDB `GET /3/tv/{id}` structural details keyed by `tmdbid`.
+const TMDB_TVDETAILS_TABLE: TableDefinition<'_, &str, &str> =
+    TableDefinition::new("tmdb_tvdetails");
+/// Cached TMDB `GET /3/{tv,movie}/{id}/external_ids` keyed by `tmdbid`.
+const TMDB_EXTIDS_TABLE: TableDefinition<'_, &str, &str> = TableDefinition::new("tmdb_extids");
+/// Cached TMDB `GET /3/movie/{id}` details keyed by `tmdbid`.
+const TMDB_MOVIEDETAILS_TABLE: TableDefinition<'_, &str, &str> =
+    TableDefinition::new("tmdb_moviedetails");
+/// Cached **ranked** TMDB `search/multi` anchors keyed by the normalized
+/// free-text query.
+const TMDB_PRINCIPAL_TOPN_TABLE: TableDefinition<'_, &str, &str> =
+    TableDefinition::new("tmdb_principal_topn");
+/// Subtitle linkage discovered at search-enrich time, keyed by the torrent's
+/// `record_id` (infohash). Value is the JSON encoding of a `Vec<SubtitleLink>`.
+const SUBTITLES_TABLE: TableDefinition<'_, &str, &str> = TableDefinition::new("subtitles");
+/// OpenSubtitles search results keyed by `"<tmdb_id>\x01<lang3>"`. Value is the
+/// resolved subtitle's cid, or the literal `"null"` negative-cache sentinel.
+const OPENSUBTITLES_TABLE: TableDefinition<'_, &str, &str> = TableDefinition::new("opensubtitles");
+/// Small durable plugin scratch values that must survive a restart but aren't
+/// content-derived — today, the torznab plugin's Prowlarr indexer-set
+/// fingerprint, so a set that changed *while the feeder was down* is still
+/// detected as a change on the next boot. Keys are plugin-namespaced
+/// (`prowlarr:indexer-set`). redb creates the table on open, so an older
+/// `.redb` file gains it transparently.
+const MISC_TABLE: TableDefinition<'_, &str, &str> = TableDefinition::new("misc");
+
+/// Per-plugin midhash cache. Cheap to clone (the inner `Database` is shared
+/// via `Arc`).
+#[derive(Clone)]
+pub struct MidhashCache {
+    db: Arc<Database>,
+}
+
+/// Generate the standard `get`/`put` accessor pair for a `&str → &str` redb
+/// table.
+macro_rules! str_table_accessors {
+    ($(#[$gmeta:meta])* $get:ident, $(#[$pmeta:meta])* $put:ident, $table:ident $(,)?) => {
+        $(#[$gmeta])*
+        pub fn $get(&self, key: &str) -> Result<Option<String>, redb::Error> {
+            let tx = self.db.begin_read()?;
+            let table = tx.open_table($table)?;
+            Ok(table.get(key)?.map(|v| v.value().to_string()))
+        }
+
+        $(#[$pmeta])*
+        pub fn $put(&self, key: &str, value: &str) -> Result<(), redb::Error> {
+            let tx = self.db.begin_write()?;
+            {
+                let mut table = tx.open_table($table)?;
+                table.insert(key, value)?;
+            }
+            tx.commit()?;
+            Ok(())
+        }
+    };
+}
+
+impl MidhashCache {
+    pub fn open(cache_dir: &Path) -> Result<Self, redb::Error> {
+        let path = cache_dir.join(CACHE_FILENAME);
+        let db = Database::create(&path)?;
+        {
+            let tx = db.begin_write()?;
+            tx.open_table(MIDHASH_TABLE)?;
+            tx.open_table(BLOBS_TABLE)?;
+            tx.open_table(COVER_CID_TABLE)?;
+            tx.open_table(BIBREC_TABLE)?;
+            tx.open_table(PREVIEW_CID_TABLE)?;
+            tx.open_table(FULLHASH_TABLE)?;
+            tx.open_table(FILELIST_TABLE)?;
+            tx.open_table(TMDB_SEARCH_TABLE)?;
+            tx.open_table(TMDB_TVDETAILS_TABLE)?;
+            tx.open_table(TMDB_EXTIDS_TABLE)?;
+            tx.open_table(TMDB_MOVIEDETAILS_TABLE)?;
+            tx.open_table(TMDB_PRINCIPAL_TOPN_TABLE)?;
+            tx.open_table(SUBTITLES_TABLE)?;
+            tx.open_table(OPENSUBTITLES_TABLE)?;
+            tx.open_table(MISC_TABLE)?;
+            tx.commit()?;
+        }
+        Ok(Self { db: Arc::new(db) })
+    }
+
+    str_table_accessors!(get_midhash, put_midhash, MIDHASH_TABLE);
+
+    str_table_accessors!(
+        /// Read a durable plugin scratch value (see [`MISC_TABLE`]).
+        get_misc,
+        /// Write a durable plugin scratch value (see [`MISC_TABLE`]).
+        put_misc,
+        MISC_TABLE,
+    );
+
+    pub fn entry_count(&self) -> Result<u64, redb::Error> {
+        let tx = self.db.begin_read()?;
+        let table = tx.open_table(MIDHASH_TABLE)?;
+        Ok(table.len()?)
+    }
+
+    pub fn get_blob(&self, cid: &str) -> Result<Option<Vec<u8>>, redb::Error> {
+        let tx = self.db.begin_read()?;
+        let table = tx.open_table(BLOBS_TABLE)?;
+        Ok(table.get(cid)?.map(|v| v.value().to_vec()))
+    }
+
+    pub fn put_blob(&self, cid: &str, bytes: &[u8]) -> Result<(), redb::Error> {
+        let tx = self.db.begin_write()?;
+        {
+            let mut table = tx.open_table(BLOBS_TABLE)?;
+            table.insert(cid, bytes)?;
+        }
+        tx.commit()?;
+        Ok(())
+    }
+
+    str_table_accessors!(get_cover_cid, put_cover_cid, COVER_CID_TABLE);
+
+    str_table_accessors!(
+        /// Read a previously-stored full-file IPFS cid for `record_id`.
+        get_fullhash,
+        /// Record the IPFS cid produced by a successful full fetch.
+        put_fullhash,
+        FULLHASH_TABLE
+    );
+
+    str_table_accessors!(
+        /// Read the cached torrent file list (JSON) for `record_id`.
+        get_filelist,
+        /// Cache the enumerated torrent file list (JSON `Vec<TorrentFile>`).
+        put_filelist,
+        FILELIST_TABLE
+    );
+
+    str_table_accessors!(
+        /// Read the cached subtitle linkage (JSON `Vec<SubtitleLink>`).
+        get_subtitles,
+        /// Cache the discovered subtitle linkage (JSON `Vec<SubtitleLink>`).
+        put_subtitles,
+        SUBTITLES_TABLE
+    );
+
+    str_table_accessors!(
+        /// Read a cached OpenSubtitles lookup by `"<tmdb_id>\x01<lang3>"`.
+        get_opensubtitles,
+        /// Cache an OpenSubtitles lookup result (cid or `"null"` sentinel).
+        put_opensubtitles,
+        OPENSUBTITLES_TABLE
+    );
+
+    str_table_accessors!(get_preview_cid, put_preview_cid, PREVIEW_CID_TABLE);
+
+    str_table_accessors!(
+        /// Read a cached TMDB search result by lookup key.
+        get_tmdb_search,
+        /// Cache a TMDB search result under `key`.
+        put_tmdb_search,
+        TMDB_SEARCH_TABLE
+    );
+
+    str_table_accessors!(
+        /// Read cached TMDB TV-details JSON by `tmdbid`.
+        get_tmdb_tvdetails,
+        /// Cache TMDB TV-details JSON under `tmdbid`.
+        put_tmdb_tvdetails,
+        TMDB_TVDETAILS_TABLE
+    );
+
+    str_table_accessors!(
+        /// Read cached TMDB external-ids JSON by `tmdbid`.
+        get_tmdb_extids,
+        /// Cache TMDB external-ids JSON under `tmdbid`.
+        put_tmdb_extids,
+        TMDB_EXTIDS_TABLE
+    );
+
+    str_table_accessors!(
+        /// Read cached TMDB movie-details JSON by `tmdbid`.
+        get_tmdb_moviedetails,
+        /// Cache TMDB movie-details JSON under `tmdbid`.
+        put_tmdb_moviedetails,
+        TMDB_MOVIEDETAILS_TABLE
+    );
+
+    str_table_accessors!(
+        /// Read the cached ranked anchor list by normalized query key.
+        get_tmdb_principal_topn,
+        /// Cache the ranked anchor list under the normalized query key.
+        put_tmdb_principal_topn,
+        TMDB_PRINCIPAL_TOPN_TABLE
+    );
+
+    pub fn get_bibrec(
+        &self,
+        record_id: &str,
+    ) -> Result<Option<std::collections::BTreeMap<String, String>>, redb::Error> {
+        let tx = self.db.begin_read()?;
+        let table = tx.open_table(BIBREC_TABLE)?;
+        let Some(v) = table.get(record_id)? else {
+            return Ok(None);
+        };
+        let s = v.value();
+        Ok(serde_json::from_str(s).ok())
+    }
+
+    pub fn put_bibrec(
+        &self,
+        record_id: &str,
+        fields: &std::collections::BTreeMap<String, String>,
+    ) -> Result<(), redb::Error> {
+        let json = serde_json::to_string(fields).unwrap_or_else(|_| "{}".to_string());
+        let tx = self.db.begin_write()?;
+        {
+            let mut table = tx.open_table(BIBREC_TABLE)?;
+            table.insert(record_id, json.as_str())?;
+        }
+        tx.commit()?;
+        Ok(())
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    fn tmp_cache_dir() -> tempfile::TempDir {
+        tempfile::tempdir().expect("tempdir")
+    }
+
+    #[test]
+    fn put_then_get_returns_value() {
+        let dir = tmp_cache_dir();
+        let cache = MidhashCache::open(dir.path()).expect("open");
+        assert_eq!(cache.get_midhash("10.1038/x").unwrap(), None);
+        cache.put_midhash("10.1038/x", "bafyXYZ").expect("put");
+        assert_eq!(
+            cache.get_midhash("10.1038/x").unwrap().as_deref(),
+            Some("bafyXYZ")
+        );
+    }
+
+    #[test]
+    fn put_overwrites_existing_value() {
+        let dir = tmp_cache_dir();
+        let cache = MidhashCache::open(dir.path()).expect("open");
+        cache.put_midhash("k", "v1").unwrap();
+        cache.put_midhash("k", "v2").unwrap();
+        assert_eq!(cache.get_midhash("k").unwrap().as_deref(), Some("v2"));
+    }
+
+    #[test]
+    fn values_persist_across_reopens() {
+        let dir = tmp_cache_dir();
+        {
+            let cache = MidhashCache::open(dir.path()).expect("open 1");
+            cache.put_midhash("k", "persistent").unwrap();
+        }
+        let cache = MidhashCache::open(dir.path()).expect("open 2");
+        assert_eq!(
+            cache.get_midhash("k").unwrap().as_deref(),
+            Some("persistent")
+        );
+    }
+
+    #[test]
+    fn tmdb_search_cache_distinguishes_miss_from_absent() {
+        let dir = tmp_cache_dir();
+        let cache = MidhashCache::open(dir.path()).expect("open");
+        assert_eq!(cache.get_tmdb_search("m\u{1}naruto\u{1}").unwrap(), None);
+        cache.put_tmdb_search("m\u{1}naruto\u{1}", "null").unwrap();
+        assert_eq!(
+            cache
+                .get_tmdb_search("m\u{1}naruto\u{1}")
+                .unwrap()
+                .as_deref(),
+            Some("null")
+        );
+        cache
+            .put_tmdb_search("t\u{1}spy x family\u{1}2019", "{\"tmdbid\":120089}")
+            .unwrap();
+        drop(cache);
+        let cache = MidhashCache::open(dir.path()).expect("reopen");
+        assert_eq!(
+            cache
+                .get_tmdb_search("t\u{1}spy x family\u{1}2019")
+                .unwrap()
+                .as_deref(),
+            Some("{\"tmdbid\":120089}")
+        );
+    }
+
+    #[test]
+    fn tmdb_tvdetails_cache_roundtrips() {
+        let dir = tmp_cache_dir();
+        let cache = MidhashCache::open(dir.path()).expect("open");
+        assert_eq!(cache.get_tmdb_tvdetails("120089").unwrap(), None);
+        cache
+            .put_tmdb_tvdetails("120089", "{\"number_of_seasons\":2}")
+            .unwrap();
+        assert_eq!(
+            cache.get_tmdb_tvdetails("120089").unwrap().as_deref(),
+            Some("{\"number_of_seasons\":2}")
+        );
+    }
+
+    #[test]
+    fn entry_count_reflects_inserts() {
+        let dir = tmp_cache_dir();
+        let cache = MidhashCache::open(dir.path()).expect("open");
+        assert_eq!(cache.entry_count().unwrap(), 0);
+        cache.put_midhash("a", "x").unwrap();
+        cache.put_midhash("b", "y").unwrap();
+        assert_eq!(cache.entry_count().unwrap(), 2);
+        cache.put_midhash("a", "x2").unwrap();
+        assert_eq!(cache.entry_count().unwrap(), 2);
+    }
+}

src/common.rs

@@ -0,0 +1,288 @@
+//! Shared helpers for single-outcome source plugins (`arxiv`, `gutenberg`,
+//! `pubmed`, `wikicommons`, `giphy`, `scihub`).
+//!
+//! These plugins are structurally near-identical: build a reqwest client, map
+//! HTTP status → [`GatewayError`], and front a per-record midhash cache whose
+//! hit/put boilerplate is the same everywhere. Only the duplicated scaffolding
+//! lives here; the genuinely-different bodies stay in the plugin modules.
+
+use std::path::Path;
+use std::time::Duration;
+
+use tracing::{debug, warn};
+
+use crate::cache::MidhashCache;
+use crate::plugin::{ConfigError, HashKind, HashOutcome};
+use crate::types::{DiscoveryRecord, GatewayError, Hash};
+
+/// Build the shared reqwest client every source plugin uses.
+pub fn build_http_client(
+    timeout_secs: u64,
+    user_agent: &str,
+    redirect: Option<reqwest::redirect::Policy>,
+) -> reqwest::Client {
+    let mut builder = reqwest::Client::builder()
+        .timeout(Duration::from_secs(timeout_secs))
+        .user_agent(user_agent);
+    if let Some(policy) = redirect {
+        builder = builder.redirect(policy);
+    }
+    builder
+        .build()
+        .expect("reqwest client build is infallible with rustls-tls")
+}
+
+/// Map a non-success HTTP status to a [`GatewayError`].
+///
+/// - `404` → [`GatewayError::NotFound`]
+/// - `429` → [`GatewayError::RateLimited`] (honours `Retry-After`, default 60s)
+/// - `5xx` → [`GatewayError::Transient`]
+/// - anything else → [`GatewayError::Permanent`]
+pub fn map_status(resp: &reqwest::Response) -> Result<(), GatewayError> {
+    let status = resp.status();
+    if status.is_success() {
+        return Ok(());
+    }
+    let code = status.as_u16();
+    if code == 404 {
+        return Err(GatewayError::NotFound);
+    }
+    if code == 429 {
+        let retry_after = resp
+            .headers()
+            .get(reqwest::header::RETRY_AFTER)
+            .and_then(|v| v.to_str().ok())
+            .and_then(|v| v.parse::<u32>().ok())
+            .unwrap_or(60);
+        return Err(GatewayError::RateLimited {
+            retry_after_s: retry_after,
+        });
+    }
+    if status.is_server_error() {
+        return Err(GatewayError::Transient(format!(
+            "upstream {} returned {status}",
+            resp.url()
+        )));
+    }
+    Err(GatewayError::Permanent(format!(
+        "upstream {} returned {status}",
+        resp.url()
+    )))
+}
+
+/// Open the per-plugin redb midhash cache, wrapping the error with the plugin
+/// name for a clean startup diagnostic.
+pub fn open_midhash_cache(
+    cache_dir: &Path,
+    plugin: &'static str,
+) -> Result<MidhashCache, ConfigError> {
+    MidhashCache::open(cache_dir).map_err(|e| ConfigError::Other {
+        plugin,
+        source: anyhow::anyhow!("open redb cache: {e}"),
+    })
+}
+
+/// Cache-hit fast path for single-outcome plugins.
+///
+/// On hit, returns `Some(vec![sparse outcome])` — hash only, no bytes/record —
+/// so the core's `(_, None)` branch skips re-storing content. `Ok(None)` is a
+/// cache miss; the caller proceeds to fetch + hash.
+pub fn cached_outcome(
+    cache: &MidhashCache,
+    record_id: &str,
+    upstream_id: &'static str,
+) -> Result<Option<Vec<HashOutcome>>, GatewayError> {
+    let Some(cached) = cache
+        .get_midhash(record_id)
+        .map_err(|e| GatewayError::Internal(anyhow::anyhow!("cache get: {e}")))?
+    else {
+        return Ok(None);
+    };
+    debug!(
+        target: "meta-share::gateway",
+        upstream = upstream_id,
+        record_id,
+        "hash cache hit"
+    );
+    Ok(Some(vec![HashOutcome {
+        hash: Hash(cached),
+        hash_kind: HashKind::Sha2_256,
+        bytes: None,
+        record: None,
+        file_extension: None,
+    }]))
+}
+
+/// Persist a freshly-computed `(record_id → cid)` mapping. A write failure is
+/// non-fatal, so it is logged and swallowed.
+pub fn store_midhash(cache: &MidhashCache, record_id: &str, upstream_id: &'static str, cid: &str) {
+    if let Err(e) = cache.put_midhash(record_id, cid) {
+        warn!(
+            target: "meta-share::gateway",
+            upstream = upstream_id,
+            record_id,
+            error = %e,
+            "hash cache put failed (non-fatal)"
+        );
+    }
+}
+
+/// Resolve the per-plugin cache handle, or produce the standard "not
+/// configured" internal error.
+pub fn require_cache<'a>(
+    cache: Option<&'a MidhashCache>,
+    plugin: &str,
+) -> Result<&'a MidhashCache, GatewayError> {
+    cache.ok_or_else(|| {
+        GatewayError::Internal(anyhow::anyhow!(
+            "{plugin} plugin not configured (configure() never called)"
+        ))
+    })
+}
+
+/// Build the single-element outcome vec a single-outcome plugin returns on a
+/// fresh (cache-miss) compute: the full bytes + record, a Sha2_256 IPFS CID,
+/// and an optional file extension.
+pub fn single_outcome(
+    cid: String,
+    bytes: bytes::Bytes,
+    record: DiscoveryRecord,
+    file_extension: Option<String>,
+) -> Vec<HashOutcome> {
+    vec![HashOutcome {
+        hash: Hash(cid),
+        hash_kind: HashKind::Sha2_256,
+        bytes: Some(bytes),
+        record: Some(record),
+        file_extension,
+    }]
+}
+
+/// Percent-encode a query-string value using the unreserved set
+/// (RFC 3986 `A-Za-z0-9-_.~`) plus `+` for space.
+pub fn urlencode(s: &str) -> String {
+    let mut out = String::with_capacity(s.len());
+    for b in s.as_bytes() {
+        match *b {
+            b'A'..=b'Z' | b'a'..=b'z' | b'0'..=b'9' | b'-' | b'_' | b'.' | b'~' => {
+                out.push(*b as char);
+            }
+            b' ' => out.push('+'),
+            other => out.push_str(&format!("%{:02X}", other)),
+        }
+    }
+    out
+}
+
+/// GET `url` and return the body bytes, mapping transport + status errors to
+/// [`GatewayError`].
+pub async fn fetch_bytes(http: &reqwest::Client, url: &str) -> Result<bytes::Bytes, GatewayError> {
+    let resp = http
+        .get(url)
+        .send()
+        .await
+        .map_err(|e| GatewayError::Transient(format!("GET {url}: {e}")))?;
+    map_status(&resp)?;
+    resp.bytes()
+        .await
+        .map_err(|e| GatewayError::Transient(format!("read body {url}: {e}")))
+}
+
+/// Like [`fetch_bytes`] but decodes the body as UTF-8 text.
+pub async fn fetch_text(http: &reqwest::Client, url: &str) -> Result<String, GatewayError> {
+    let resp = http
+        .get(url)
+        .send()
+        .await
+        .map_err(|e| GatewayError::Transient(format!("GET {url}: {e}")))?;
+    map_status(&resp)?;
+    resp.text()
+        .await
+        .map_err(|e| GatewayError::Transient(format!("read body {url}: {e}")))
+}
+
+/// Decode a v1 BitTorrent infohash string into its raw 20 bytes.
+///
+/// Accepts 40 hex chars (case-insensitive) or 32 base32 chars (RFC 4648,
+/// case-insensitive). Returns `None` for anything else.
+pub fn decode_infohash(s: &str) -> Option<[u8; 20]> {
+    let bytes = s.as_bytes();
+    let raw: Vec<u8> = if bytes.len() == 40 && bytes.iter().all(u8::is_ascii_hexdigit) {
+        let mut out = Vec::with_capacity(20);
+        for pair in bytes.chunks(2) {
+            out.push((hex_nibble(pair[0])? << 4) | hex_nibble(pair[1])?);
+        }
+        out
+    } else if bytes.len() == 32 && bytes.iter().all(u8::is_ascii_alphanumeric) {
+        decode_base32_20(bytes)?
+    } else {
+        return None;
+    };
+    raw.try_into().ok()
+}
+
+fn hex_nibble(b: u8) -> Option<u8> {
+    match b {
+        b'0'..=b'9' => Some(b - b'0'),
+        b'a'..=b'f' => Some(b - b'a' + 10),
+        b'A'..=b'F' => Some(b - b'A' + 10),
+        _ => None,
+    }
+}
+
+/// Decode 32 RFC-4648 base32 chars (case-insensitive, no padding) into the 20
+/// bytes they encode.
+fn decode_base32_20(chars: &[u8]) -> Option<Vec<u8>> {
+    let mut out = Vec::with_capacity(20);
+    let mut buffer: u64 = 0;
+    let mut bits: u32 = 0;
+    for &c in chars {
+        let val = match c {
+            b'A'..=b'Z' => c - b'A',
+            b'a'..=b'z' => c - b'a',
+            b'2'..=b'7' => c - b'2' + 26,
+            _ => return None,
+        } as u64;
+        buffer = (buffer << 5) | val;
+        bits += 5;
+        if bits >= 8 {
+            bits -= 8;
+            out.push((buffer >> bits) as u8);
+        }
+    }
+    Some(out)
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn decode_infohash_hex_roundtrips() {
+        let hex = "0123456789abcdef0123456789abcdef01234567";
+        let raw = decode_infohash(hex).expect("hex decodes");
+        assert_eq!(raw[0], 0x01);
+        assert_eq!(raw[19], 0x67);
+    }
+
+    #[test]
+    fn decode_infohash_is_case_insensitive_hex() {
+        let lower = decode_infohash("aabbccddeeff00112233445566778899aabbccdd");
+        let upper = decode_infohash("AABBCCDDEEFF00112233445566778899AABBCCDD");
+        assert!(lower.is_some());
+        assert_eq!(lower, upper);
+    }
+
+    #[test]
+    fn decode_infohash_accepts_base32() {
+        let raw = decode_infohash("MFRGGZDFMZTWQ2LKNNWG23TPOBYXE43U");
+        assert!(raw.is_some());
+    }
+
+    #[test]
+    fn decode_infohash_rejects_wrong_shape() {
+        assert!(decode_infohash("tooshort").is_none());
+        assert!(decode_infohash("zz23456789abcdef0123456789abcdef01234567").is_none());
+        assert!(decode_infohash("").is_none());
+    }
+}

src/config.rs

@@ -0,0 +1,312 @@
+//! Self-describing per-plugin configuration: schema, redaction, merge, and the
+//! generic schema-driven HTML page the feeder serves at `/config`.
+//!
+//! The point of this module is that **the gateway carries no per-plugin config
+//! knowledge** and **the SDK carries no per-plugin field names**. A plugin
+//! declares its fields via [`FeederPlugin::config_schema`](crate::FeederPlugin::config_schema);
+//! everything here (redaction of secrets, merge-on-save, and the rendered form)
+//! is driven entirely by that schema. Add a feeder → it shows up with a working
+//! config form and zero UI/gateway changes.
+//!
+//! ## Persistence & precedence
+//!
+//! Config lives at `cache_dir/config.json` (the per-plugin dir handed to
+//! `configure()`). The plugin reads **file-or-env** at startup: env is the
+//! first-boot seed and stays authoritative until the operator saves through the
+//! UI, at which point `config.json` exists and wins. There is no runtime reload
+//! — a save returns `restart_required: true` (mirrors the gateway's
+//! `gateway-config.json` posture).
+//!
+//! ## Secrets
+//!
+//! Fields of kind [`FieldKind::Secret`] are **write-only**: never returned to
+//! the page (redacted to a `<key>_set: bool`), and a blank incoming value on
+//! save means "keep the stored secret".
+
+use serde::{Deserialize, Serialize};
+use serde_json::{Map, Value};
+
+/// A plugin's full config surface — an ordered list of fields.
+#[derive(Serialize, Deserialize, Clone, Debug, Default)]
+pub struct ConfigSchema {
+    pub fields: Vec<ConfigField>,
+}
+
+impl ConfigSchema {
+    /// Convenience: `true` when the plugin declares no configurable fields (the
+    /// page then renders a "no configuration required" notice).
+    pub fn is_empty(&self) -> bool {
+        self.fields.is_empty()
+    }
+}
+
+/// One configurable field. `record_array` fields nest `fields` for the
+/// per-record sub-schema (e.g. torznab's `indexers`).
+#[derive(Serialize, Deserialize, Clone, Debug)]
+pub struct ConfigField {
+    /// JSON key in the config object.
+    pub key: String,
+    /// Human label for the form.
+    pub label: String,
+    #[serde(rename = "type")]
+    pub kind: FieldKind,
+    #[serde(default, skip_serializing_if = "Option::is_none")]
+    pub help: Option<String>,
+    #[serde(default)]
+    pub required: bool,
+    /// Sub-fields for [`FieldKind::RecordArray`]. The FIRST sub-field is treated
+    /// as the record identifier for secret back-fill on merge (e.g. `name`).
+    #[serde(default, skip_serializing_if = "Option::is_none")]
+    pub fields: Option<Vec<ConfigField>>,
+}
+
+impl ConfigField {
+    pub fn text(key: &str, label: &str) -> Self {
+        Self::new(key, label, FieldKind::Text)
+    }
+    pub fn secret(key: &str, label: &str) -> Self {
+        Self::new(key, label, FieldKind::Secret)
+    }
+    pub fn bool(key: &str, label: &str) -> Self {
+        Self::new(key, label, FieldKind::Bool)
+    }
+    pub fn number(key: &str, label: &str) -> Self {
+        Self::new(key, label, FieldKind::Number)
+    }
+    pub fn list(key: &str, label: &str) -> Self {
+        Self::new(key, label, FieldKind::List)
+    }
+    pub fn record_array(key: &str, label: &str, fields: Vec<ConfigField>) -> Self {
+        let mut f = Self::new(key, label, FieldKind::RecordArray);
+        f.fields = Some(fields);
+        f
+    }
+    fn new(key: &str, label: &str, kind: FieldKind) -> Self {
+        Self {
+            key: key.to_string(),
+            label: label.to_string(),
+            kind,
+            help: None,
+            required: false,
+            fields: None,
+        }
+    }
+    pub fn with_help(mut self, help: &str) -> Self {
+        self.help = Some(help.to_string());
+        self
+    }
+    pub fn required(mut self) -> Self {
+        self.required = true;
+        self
+    }
+}
+
+/// Field widget / value type. Drives both rendering and the secret/merge rules.
+#[derive(Serialize, Deserialize, Clone, Copy, Debug, PartialEq, Eq)]
+#[serde(rename_all = "snake_case")]
+pub enum FieldKind {
+    /// Free text → JSON string.
+    Text,
+    /// Write-only secret → JSON string; redacted on read, "blank keeps" on save.
+    Secret,
+    /// Checkbox → JSON bool.
+    Bool,
+    /// Numeric input → JSON number.
+    Number,
+    /// Comma/line list → JSON array of strings.
+    List,
+    /// Repeatable record → JSON array of objects keyed by nested `fields`.
+    RecordArray,
+}
+
+fn is_blank(v: Option<&Value>) -> bool {
+    match v {
+        None | Some(Value::Null) => true,
+        Some(Value::String(s)) => s.is_empty(),
+        _ => false,
+    }
+}
+
+/// Produce a UI-safe view of `values`: secret fields are dropped and replaced
+/// with a `<key>_set` boolean; everything else passes through. Recurses into
+/// `record_array` records for secret sub-fields.
+pub fn redact(values: &Value, schema: &ConfigSchema) -> Value {
+    let src = values.as_object().cloned().unwrap_or_default();
+    Value::Object(redact_object(&src, &schema.fields))
+}
+
+fn redact_object(src: &Map<String, Value>, fields: &[ConfigField]) -> Map<String, Value> {
+    let mut out = Map::new();
+    for f in fields {
+        match f.kind {
+            FieldKind::Secret => {
+                let set = !is_blank(src.get(&f.key));
+                out.insert(format!("{}_set", f.key), Value::Bool(set));
+            }
+            FieldKind::RecordArray => {
+                let subs = f.fields.as_deref().unwrap_or(&[]);
+                let arr = src
+                    .get(&f.key)
+                    .and_then(Value::as_array)
+                    .map(|recs| {
+                        recs.iter()
+                            .map(|r| {
+                                let m = r.as_object().cloned().unwrap_or_default();
+                                Value::Object(redact_object(&m, subs))
+                            })
+                            .collect::<Vec<_>>()
+                    })
+                    .unwrap_or_default();
+                out.insert(f.key.clone(), Value::Array(arr));
+            }
+            _ => {
+                if let Some(v) = src.get(&f.key) {
+                    out.insert(f.key.clone(), v.clone());
+                }
+            }
+        }
+    }
+    out
+}
+
+/// Merge `incoming` (from the UI) onto `base` (the stored/effective config),
+/// schema-aware. Returns the full, UNREDACTED object to persist:
+/// - secret: blank/absent incoming keeps `base`; non-blank overwrites.
+/// - text/number/bool/list: present in incoming overwrites; absent keeps base.
+/// - record_array: incoming array replaces base, but blank secret sub-fields are
+///   back-filled from the base record matched by the first sub-field (identifier).
+pub fn merge(base: &Value, incoming: &Value, schema: &ConfigSchema) -> Value {
+    let base_obj = base.as_object().cloned().unwrap_or_default();
+    let inc_obj = incoming.as_object().cloned().unwrap_or_default();
+    Value::Object(merge_object(&base_obj, &inc_obj, &schema.fields))
+}
+
+fn merge_object(
+    base: &Map<String, Value>,
+    inc: &Map<String, Value>,
+    fields: &[ConfigField],
+) -> Map<String, Value> {
+    let mut out = base.clone();
+    for f in fields {
+        match f.kind {
+            FieldKind::Secret => {
+                if !is_blank(inc.get(&f.key)) {
+                    out.insert(f.key.clone(), inc.get(&f.key).cloned().unwrap());
+                }
+                // blank/absent → keep base (no-op)
+            }
+            FieldKind::RecordArray => {
+                let subs = f.fields.as_deref().unwrap_or(&[]);
+                let id_key = subs.first().map(|s| s.key.clone());
+                let base_recs = base.get(&f.key).and_then(Value::as_array).cloned();
+                let inc_recs = match inc.get(&f.key).and_then(Value::as_array) {
+                    Some(r) => r.clone(),
+                    None => continue, // absent → keep base array untouched
+                };
+                let merged: Vec<Value> = inc_recs
+                    .iter()
+                    .map(|rec| {
+                        let rec_obj = rec.as_object().cloned().unwrap_or_default();
+                        // Find the matching base record by identifier sub-field.
+                        let base_match = match (&id_key, base_recs.as_ref()) {
+                            (Some(idk), Some(brs)) => brs
+                                .iter()
+                                .find(|br| br.get(idk) == rec_obj.get(idk))
+                                .and_then(Value::as_object)
+                                .cloned()
+                                .unwrap_or_default(),
+                            _ => Map::new(),
+                        };
+                        Value::Object(merge_object(&base_match, &rec_obj, subs))
+                    })
+                    .collect();
+                out.insert(f.key.clone(), Value::Array(merged));
+            }
+            _ => {
+                if let Some(v) = inc.get(&f.key) {
+                    out.insert(f.key.clone(), v.clone());
+                }
+            }
+        }
+    }
+    out
+}
+
+/// The generic, schema-driven config page served at `GET /config`. Self-contained
+/// (inline CSS + JS, no external assets) so it loads identically when hit
+/// directly on the feeder OR reverse-proxied through the gateway. All API calls
+/// are relative to `location.pathname`, so the proxy mount prefix is irrelevant.
+pub const CONFIG_PAGE_HTML: &str = include_str!("config_page.html");
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use serde_json::json;
+
+    fn torznab_like() -> ConfigSchema {
+        ConfigSchema {
+            fields: vec![
+                ConfigField::secret("tmdb_token", "TMDB token"),
+                ConfigField::bool("resolve_torrent_files", "Resolve .torrent"),
+                ConfigField::record_array(
+                    "indexers",
+                    "Indexers",
+                    vec![
+                        ConfigField::text("name", "Name"),
+                        ConfigField::secret("api_key", "API key"),
+                    ],
+                ),
+            ],
+        }
+    }
+
+    #[test]
+    fn redact_hides_secrets_and_flags_set() {
+        let v = json!({
+            "tmdb_token": "abc",
+            "resolve_torrent_files": true,
+            "indexers": [{"name":"prowlarr","api_key":"k"}]
+        });
+        let r = redact(&v, &torznab_like());
+        assert_eq!(r["tmdb_token_set"], json!(true));
+        assert!(r.get("tmdb_token").is_none());
+        assert_eq!(r["resolve_torrent_files"], json!(true));
+        assert_eq!(r["indexers"][0]["name"], json!("prowlarr"));
+        assert_eq!(r["indexers"][0]["api_key_set"], json!(true));
+        assert!(r["indexers"][0].get("api_key").is_none());
+    }
+
+    #[test]
+    fn merge_blank_secret_keeps_base() {
+        let base = json!({"tmdb_token": "keepme"});
+        let inc = json!({"tmdb_token": ""});
+        let m = merge(&base, &inc, &torznab_like());
+        assert_eq!(m["tmdb_token"], json!("keepme"));
+    }
+
+    #[test]
+    fn merge_nonblank_secret_overwrites() {
+        let base = json!({"tmdb_token": "old"});
+        let inc = json!({"tmdb_token": "new"});
+        let m = merge(&base, &inc, &torznab_like());
+        assert_eq!(m["tmdb_token"], json!("new"));
+    }
+
+    #[test]
+    fn merge_record_array_backfills_blank_secret_by_identifier() {
+        let base = json!({"indexers":[{"name":"prowlarr","api_key":"secret"}]});
+        // UI re-submits the indexer with a blank api_key → keep the stored one.
+        let inc = json!({"indexers":[{"name":"prowlarr","api_key":""}]});
+        let m = merge(&base, &inc, &torznab_like());
+        assert_eq!(m["indexers"][0]["api_key"], json!("secret"));
+        assert_eq!(m["indexers"][0]["name"], json!("prowlarr"));
+    }
+
+    #[test]
+    fn merge_bool_overwrites_when_present() {
+        let base = json!({"resolve_torrent_files": true});
+        let inc = json!({"resolve_torrent_files": false});
+        let m = merge(&base, &inc, &torznab_like());
+        assert_eq!(m["resolve_torrent_files"], json!(false));
+    }
+}

src/config_page.html

@@ -0,0 +1,268 @@
+<!DOCTYPE html>
+<html lang="en">
+<head>
+<meta charset="utf-8" />
+<meta name="viewport" content="width=device-width, initial-scale=1" />
+<title>feeder config</title>
+<style>
+  :root { color-scheme: dark; }
+  * { box-sizing: border-box; }
+  body {
+    margin: 0; padding: 18px;
+    font: 14px/1.5 system-ui, -apple-system, Segoe UI, Roboto, sans-serif;
+    background: #0d0d12; color: #e6e6ea;
+  }
+  h1 { font-size: 16px; margin: 0 0 4px; }
+  .sub { color: #9a9aa6; font-size: 12px; margin: 0 0 16px; }
+  .field { margin: 0 0 16px; }
+  .field > label { display: block; font-weight: 600; margin: 0 0 4px; }
+  .help { color: #8a8a96; font-size: 12px; margin: 3px 0 0; }
+  .req { color: #f0a0a0; margin-left: 3px; font-weight: 700; }
+  input[type=text], input[type=password], input[type=number], textarea {
+    width: 100%; padding: 8px 10px; border-radius: 8px;
+    border: 1px solid #2a2a35; background: #15151c; color: #e6e6ea; font: inherit;
+  }
+  textarea { min-height: 56px; resize: vertical; }
+  input[type=checkbox] { width: 16px; height: 16px; vertical-align: middle; }
+  .pill { font-size: 10px; padding: 2px 7px; border-radius: 999px; margin-left: 8px; vertical-align: middle; }
+  .pill.set { background: #14361f; color: #6ee7a0; border: 1px solid #1f5132; }
+  .pill.unset { background: #2a2a35; color: #b9b9c4; border: 1px solid #3a3a45; }
+  .record { border: 1px solid #2a2a35; border-radius: 10px; padding: 12px; margin: 0 0 10px; background: #111118; }
+  .record .field { margin-bottom: 10px; }
+  .row-actions { text-align: right; }
+  button {
+    font: inherit; cursor: pointer; border-radius: 8px; padding: 7px 14px;
+    border: 1px solid #3a3a45; background: #1c1c26; color: #e6e6ea;
+  }
+  button.primary { background: #6d4aff; border-color: #6d4aff; color: #fff; font-weight: 600; }
+  button.danger { background: transparent; border-color: #5a2a2a; color: #e29; padding: 4px 10px; }
+  button.add { margin-top: 4px; }
+  .bar { position: sticky; bottom: 0; padding: 12px 0 2px; background: linear-gradient(#0d0d1200, #0d0d12 30%); }
+  .banner { padding: 9px 12px; border-radius: 8px; margin: 0 0 14px; font-size: 13px; display: none; }
+  .banner.ok { background: #14361f; color: #9ff0bf; border: 1px solid #1f5132; display: block; }
+  .banner.warn { background: #3a2f12; color: #f0d79f; border: 1px solid #5a4a1f; display: block; }
+  .banner.err { background: #3a1414; color: #f0a0a0; border: 1px solid #5a2020; display: block; }
+  .empty { color: #9a9aa6; }
+</style>
+</head>
+<body>
+  <h1 id="title">Plugin configuration</h1>
+  <p class="sub">Secrets are write-only — set values are shown as “set”, never echoed back. Saving requires a feeder restart to take effect. Fields marked <span class="req">*</span> are required.</p>
+  <div id="banner" class="banner"></div>
+  <form id="form"></form>
+  <div class="bar" id="bar" style="display:none">
+    <button type="button" class="primary" id="save">Save</button>
+  </div>
+
+<script>
+// All API calls are relative to this page's path, so the same page works when
+// served directly on the feeder (/config) or reverse-proxied through the
+// gateway (/api/gateway/plugins/<id>/ui/config).
+const BASE = location.pathname.replace(/\/+$/, "");
+let SCHEMA = { fields: [] };
+let VALUES = {};
+
+const $ = (id) => document.getElementById(id);
+function banner(kind, msg) {
+  const b = $("banner");
+  b.className = "banner " + kind;
+  b.textContent = msg;
+}
+
+function el(tag, attrs, ...kids) {
+  const e = document.createElement(tag);
+  for (const [k, v] of Object.entries(attrs || {})) {
+    if (k === "class") e.className = v;
+    else if (k === "text") e.textContent = v;
+    else if (k in e) e[k] = v;
+    else e.setAttribute(k, v);
+  }
+  for (const c of kids) if (c != null) e.append(c);
+  return e;
+}
+
+// Split help text into plain runs + clickable <a> nodes for any http(s) URL.
+// Built as DOM nodes (never innerHTML) so help stays XSS-safe; trailing
+// punctuation is kept outside the link so "see http://host/ui." reads right.
+function linkify(text) {
+  const out = [];
+  const re = /https?:\/\/[^\s]+/g;
+  let last = 0, m;
+  while ((m = re.exec(text)) !== null) {
+    if (m.index > last) out.push(text.slice(last, m.index));
+    let url = m[0], trail = "";
+    const t = url.match(/[.,;:)\]]+$/);
+    if (t) { trail = t[0]; url = url.slice(0, -trail.length); }
+    out.push(el("a", { href: url, target: "_blank", rel: "noopener noreferrer", text: url }));
+    if (trail) out.push(trail);
+    last = m.index + m[0].length;
+  }
+  if (last < text.length) out.push(text.slice(last));
+  return out;
+}
+
+function helpEl(f) { return f.help ? el("p", { class: "help" }, ...linkify(f.help)) : null; }
+
+// A "*" marker for required fields (null for optional ones).
+function reqStar(f) { return f.required ? el("span", { class: "req", text: "*", title: "required" }) : null; }
+
+// Render one scalar field. `vals` is the object holding the value/`_set` flag.
+// Every returned widget exposes `_collect()` and `_key` so collect() can read it.
+function fieldInput(f, vals) {
+  if (f.type === "bool") {
+    const cb = el("input", { type: "checkbox" });
+    cb.checked = vals[f.key] === true;
+    const w = el("div", { class: "field" },
+      el("label", {}, cb, " ", el("span", { text: " " + f.label }), reqStar(f)),
+      helpEl(f));
+    w._collect = () => cb.checked;
+    w._key = f.key;
+    return w;
+  }
+  const label = el("label", { text: f.label });
+  const star = reqStar(f); if (star) label.append(star);
+  let input;
+  if (f.type === "secret") {
+    const isSet = vals[f.key + "_set"] === true;
+    input = el("input", { type: "password", placeholder: isSet ? "•••••••• (blank keeps current)" : "not set" });
+    label.append(el("span", { class: "pill " + (isSet ? "set" : "unset"), text: isSet ? "set" : "not set" }));
+    input._get = () => input.value; // blank => merge keeps stored secret
+  } else if (f.type === "number") {
+    input = el("input", { type: "number" });
+    if (vals[f.key] != null) input.value = vals[f.key];
+    input._get = () => (input.value === "" ? null : Number(input.value));
+  } else if (f.type === "list") {
+    input = el("textarea", { placeholder: "one per line or comma-separated" });
+    const arr = Array.isArray(vals[f.key]) ? vals[f.key] : [];
+    input.value = arr.join("\n");
+    input._get = () => input.value.split(/[\n,]/).map((s) => s.trim()).filter(Boolean);
+  } else {
+    input = el("input", { type: "text" });
+    if (vals[f.key] != null) input.value = vals[f.key];
+    input._get = () => input.value;
+  }
+  const wrap = el("div", { class: "field" }, label, input, helpEl(f));
+  wrap._collect = () => input._get();
+  wrap._key = f.key;
+  return wrap;
+}
+
+// Render a record_array (repeatable group). Returns a wrapper exposing _collect.
+function recordArray(f, vals) {
+  const subs = f.fields || [];
+  const idKey = subs.length ? subs[0].key : null;
+  const list = el("div", {});
+  const records = Array.isArray(vals[f.key]) ? vals[f.key].slice() : [];
+
+  function addRecord(recVals) {
+    const card = el("div", { class: "record" });
+    const inputs = subs.map((sf) => {
+      const fi = fieldInput(sf, recVals || {});
+      card.append(fi);
+      return fi;
+    });
+    const rm = el("button", { type: "button", class: "danger", text: "remove" });
+    rm.onclick = () => card.remove();
+    card.append(el("div", { class: "row-actions" }, rm));
+    card._collect = () => {
+      const o = {};
+      for (const fi of inputs) o[fi._key] = fi._collect();
+      return o;
+    };
+    list.append(card);
+    return card;
+  }
+
+  records.forEach((r) => addRecord(r));
+  const add = el("button", { type: "button", class: "add", text: "+ add " + f.label.toLowerCase().replace(/s$/, "") });
+  add.onclick = () => addRecord({});
+
+  const lbl = el("label", { text: f.label });
+  const star = reqStar(f); if (star) lbl.append(star);
+  const wrap = el("div", { class: "field" }, lbl, helpEl(f), list, add);
+  wrap._key = f.key;
+  wrap._collect = () => Array.from(list.children).map((c) => c._collect());
+  return wrap;
+}
+
+function render() {
+  $("title").textContent = (SCHEMA.title || "Plugin") + " configuration";
+  const form = $("form");
+  form.innerHTML = "";
+  if (!SCHEMA.fields || !SCHEMA.fields.length) {
+    form.append(el("p", { class: "empty", text: "No configuration required for this plugin." }));
+    $("bar").style.display = "none";
+    return;
+  }
+  const widgets = [];
+  for (const f of SCHEMA.fields) {
+    const w = f.type === "record_array" ? recordArray(f, VALUES) : fieldInput(f, VALUES);
+    widgets.push(w);
+    form.append(w);
+  }
+  form._widgets = widgets;
+  $("bar").style.display = "block";
+}
+
+function collect() {
+  const out = {};
+  for (const w of $("form")._widgets || []) out[w._key] = w._collect();
+  return out;
+}
+
+async function save() {
+  $("save").disabled = true;
+  try {
+    const res = await fetch(BASE + "/values", {
+      method: "PUT",
+      headers: { "Content-Type": "application/json" },
+      body: JSON.stringify(collect()),
+    });
+    if (!res.ok) {
+      const detail = (await res.text().catch(() => "")).trim();
+      throw new Error(detail ? `the feeder rejected it (HTTP ${res.status}): ${detail}`
+                             : `the feeder returned HTTP ${res.status}`);
+    }
+    const j = await res.json().catch(() => ({}));
+    if (j.reloading) {
+      // The feeder is restarting itself (~2-3s) to apply the change. Poll it
+      // back up, then refresh the form so secret pills reflect stored state.
+      banner("warn", "Saved — reloading the feeder to apply (~3 s)…");
+      let tries = 6;
+      const poll = async () => {
+        try { await load(); banner("ok", "Reloaded — new config applied."); }
+        catch { if (--tries > 0) setTimeout(poll, 1500); else banner("warn", "Saved & reloading — reopen this panel shortly to confirm."); }
+      };
+      setTimeout(poll, 3000);
+    } else {
+      if (j.restart_required) banner("warn", "Saved. Restart the feeder container for changes to take effect.");
+      else banner("ok", "Saved.");
+      // Re-fetch so secret pills reflect the new stored state.
+      await load();
+    }
+  } catch (e) {
+    const msg = (e && e.message) ? e.message : String(e);
+    const friendly = /Failed to fetch|NetworkError|load failed/i.test(msg)
+      ? "couldn't reach the feeder — it may be restarting; wait a moment and try again."
+      : msg;
+    banner("err", "Could not save: " + friendly);
+  } finally {
+    $("save").disabled = false;
+  }
+}
+
+async function load() {
+  const [s, v] = await Promise.all([
+    fetch(BASE + "/schema").then((r) => r.json()),
+    fetch(BASE + "/values").then((r) => r.json()),
+  ]);
+  SCHEMA = s || { fields: [] };
+  VALUES = v || {};
+  render();
+}
+
+$("save").onclick = save;
+load().catch((e) => banner("err", "Failed to load config: " + e.message));
+</script>
+</body>
+</html>

src/enrich.rs

@@ -0,0 +1,614 @@
+//! Feeder-driven enrichment — the "smart feeder / dumb gateway" pipeline.
+//!
+//! A feeder that self-publishes (has a `META_CORE_URL`) writes its own base
+//! record, then drives the **reused meta-sort enrichment plugins**
+//! (`metamesh-plugin-filename-parser`, `metamesh-plugin-tmdb`) over HTTP. Each
+//! plugin is handed the `metaCoreUrl` and writes its own fields straight back to
+//! meta-core (`PATCH /meta/{cid}` merge), so the gateway never touches
+//! enrichment — full separation of concerns.
+//!
+//! ## Ordering — why we poll
+//!
+//! tmdb searches on `originalTitle`/`movieYear`/`videoType` (which it reads from
+//! the record), and those are produced by filename-parser. So the pipeline is
+//! **filename-parser → tmdb**. The plugin `/process` contract is *async*
+//! (returns `accepted`, then writes to meta-core and POSTs a callback), so after
+//! kicking filename-parser we **poll meta-core** until `originalTitle` appears
+//! (bounded), read the merged fields back, and hand them to tmdb. Polling keeps
+//! the feeder stateless — no callback-correlation bookkeeping. The plugins'
+//! callback POSTs still fire; they hit the feeder's no-op `/enrich/callback`.
+//!
+//! The whole pipeline runs in a spawned background task so it never adds latency
+//! to the libp2p resolve path; the meta-share ingester propagates the enriched
+//! record on its next poll (~eventually consistent).
+
+use std::collections::BTreeMap;
+use std::sync::Arc;
+use std::time::{Duration, SystemTime, UNIX_EPOCH};
+
+use serde::Serialize;
+use tracing::{debug, warn};
+
+use crate::meta_core::{self, Provenance};
+use crate::types::DiscoveryRecord;
+
+/// Operator-supplied enrichment wiring, parsed once from the feeder env.
+#[derive(Clone, Debug)]
+pub struct EnrichmentConfig {
+    /// meta-core root the feeder self-publishes to + hands to the plugins.
+    pub meta_core_url: String,
+    /// `metamesh-plugin-filename-parser` base URL (optional).
+    pub filename_parser_url: Option<String>,
+    /// `metamesh-plugin-tmdb` base URL (optional).
+    pub tmdb_url: Option<String>,
+    /// TMDB v3 key / v4 bearer token, POSTed to tmdb `/configure`.
+    pub tmdb_token: Option<String>,
+    /// TMDB metadata language (default `en-US`).
+    pub tmdb_language: String,
+    /// Stable per-deployment id stamped into `provenance.gatewayPeer`.
+    pub gateway_peer: String,
+    /// URL the plugins POST their completion callback to (the feeder's own
+    /// no-op `/enrich/callback`). Polling is the real completion signal; this
+    /// only keeps the plugins from logging a failed-callback warning.
+    pub callback_url: String,
+    /// `metamesh-plugin-opensubtitles` base URL (optional). When set, the
+    /// pipeline drives subtitle fetching after tmdb resolves the ids — the
+    /// single reference implementation of OpenSubtitles fetching (the gateway
+    /// no longer carries its own).
+    pub opensubtitles_url: Option<String>,
+    /// OpenSubtitles consumer API key, POSTed to the plugin's `/configure`.
+    pub opensubtitles_api_key: Option<String>,
+    /// OpenSubtitles account username (required by the plugin for downloads).
+    pub opensubtitles_username: Option<String>,
+    /// OpenSubtitles account password.
+    pub opensubtitles_password: Option<String>,
+    /// Wanted subtitle languages (CSV of ISO 639-1 codes; default `en`).
+    pub opensubtitles_languages: String,
+}
+
+fn env_nonempty(key: &str) -> Option<String> {
+    std::env::var(key)
+        .ok()
+        .map(|s| s.trim().to_string())
+        .filter(|s| !s.is_empty())
+}
+
+/// Derive a co-bundled sidecar plugin URL from the feeder's own hostname, by the
+/// app-compose convention `<prefix>-feeder` → `<prefix>-<plugin>:8080`
+/// (e.g. `metafeedertorznab-feeder` → `http://metafeedertorznab-tmdb:8080`). Lets
+/// a feeder reach its bundled filename-parser / tmdb sidecars with **no explicit
+/// `*_PLUGIN_URL` env** — config lives in the UI, wiring is derived. Returns
+/// `None` when `HOSTNAME` is unset or not in `<prefix>-feeder` form, in which case
+/// the caller falls back to the env seed (then soft-skips that plugin).
+fn derive_sidecar_url(plugin: &str) -> Option<String> {
+    let host = env_nonempty("HOSTNAME")?;
+    let prefix = host.strip_suffix("-feeder")?;
+    Some(format!("http://{prefix}-{plugin}:8080"))
+}
+
+impl EnrichmentConfig {
+    /// Parse from the feeder env. Returns `None` when `META_CORE_URL` is unset —
+    /// the **bundled-feeder** path (records returned over HTTP, the gateway
+    /// dispatcher stores them). Self-publishing feeders that source meta-core from
+    /// their own dashboard config use [`from_meta_core`](Self::from_meta_core).
+    pub fn from_env() -> Option<Self> {
+        Some(Self::from_meta_core(env_nonempty("META_CORE_URL")?))
+    }
+
+    /// Build with an explicit meta-core root — sourced from the feeder's own
+    /// `config.json` (dashboard) when set, else the `META_CORE_URL` env seed. The
+    /// sidecar URLs come from their `*_PLUGIN_URL` env, falling back to the
+    /// hostname-derived co-bundled sidecar (see [`derive_sidecar_url`]); the rest
+    /// keep their env seeds / defaults. Secrets (tmdb token, language) are
+    /// overlaid by the caller from the per-feeder config.
+    pub fn from_meta_core(meta_core_url: String) -> Self {
+        EnrichmentConfig {
+            meta_core_url,
+            filename_parser_url: env_nonempty("FILENAME_PARSER_URL")
+                .or_else(|| derive_sidecar_url("filename-parser")),
+            tmdb_url: env_nonempty("TMDB_PLUGIN_URL").or_else(|| derive_sidecar_url("tmdb")),
+            tmdb_token: env_nonempty("TMDB_TOKEN").or_else(|| env_nonempty("TORZNAB_TMDB_TOKEN")),
+            tmdb_language: env_nonempty("TMDB_LANGUAGE").unwrap_or_else(|| "en-US".to_string()),
+            gateway_peer: env_nonempty("META_GATEWAY_PEER_ID")
+                .or_else(|| env_nonempty("HOSTNAME"))
+                .unwrap_or_else(|| "gateway-feeder".to_string()),
+            callback_url: env_nonempty("META_FEEDER_CALLBACK_URL")
+                .unwrap_or_else(|| "http://127.0.0.1:8080/enrich/callback".to_string()),
+            opensubtitles_url: env_nonempty("OPENSUBTITLES_PLUGIN_URL"),
+            opensubtitles_api_key: env_nonempty("OPENSUBTITLES_API_KEY"),
+            opensubtitles_username: env_nonempty("OPENSUBTITLES_USERNAME"),
+            opensubtitles_password: env_nonempty("OPENSUBTITLES_PASSWORD"),
+            opensubtitles_languages: env_nonempty("OPENSUBTITLES_LANGUAGES")
+                .unwrap_or_else(|| "en".to_string()),
+        }
+    }
+}
+
+/// How long to wait for filename-parser to merge `originalTitle` before handing
+/// off to tmdb. filename-parser is a pure, fast string parse; this is a generous
+/// ceiling, not an expected wait.
+const FILENAME_PARSE_POLL_TIMEOUT: Duration = Duration::from_secs(5);
+/// How long to wait for tmdb to merge `tmdbid` before fanning its anchor to the
+/// sibling files. tmdb hits the network, so a longer ceiling than filename.
+const TMDB_POLL_TIMEOUT: Duration = Duration::from_secs(20);
+const POLL_INTERVAL: Duration = Duration::from_millis(200);
+
+/// Show-level TMDB fields that are **fanned** from the primary file to every
+/// sibling file in a multi-file (season-pack) torrent — they're identical for
+/// every episode of a show, so we resolve tmdb **once** and copy these across
+/// (avoids N TMDB lookups; the tmdb plugin caches by `cid_midhash256`, which
+/// gateway BT records don't carry, so without this each file would re-hit TMDB).
+/// Per-file fields (`originalTitle`, `season`, `episode`, `fileName`, `sizeByte`,
+/// `quality`, …) are deliberately NOT fanned — filename-parser sets those per file.
+const ANCHOR_EXACT: &[&str] = &[
+    "tmdbid",
+    "imdbid",
+    "poster",
+    "backdrop",
+    "rating",
+    "releasedate",
+    "studio",
+    "genres",
+    "tags",
+];
+const ANCHOR_PREFIXES: &[&str] = &["plot/", "genres/", "studio/", "tags/"];
+
+/// One file (or pack) to enrich: its CID, the filename to parse, and the base
+/// fields already written to meta-core (handed to the plugins as `existingMeta`).
+#[derive(Clone, Debug)]
+pub struct EnrichTarget {
+    pub cid: String,
+    pub file_name: String,
+    pub base: BTreeMap<String, String>,
+}
+
+/// Drives meta-core writes + the enrichment plugins for one feeder. Cheap to
+/// clone (just a reqwest client + an `Arc<config>`), so it can be moved into a
+/// spawned per-resolve task.
+#[derive(Clone)]
+pub struct Enricher {
+    http: reqwest::Client,
+    cfg: Arc<EnrichmentConfig>,
+}
+
+#[derive(Serialize)]
+struct ProcessRequest<'a> {
+    #[serde(rename = "taskId")]
+    task_id: String,
+    cid: &'a str,
+    #[serde(rename = "filePath")]
+    file_path: &'a str,
+    #[serde(rename = "callbackUrl")]
+    callback_url: &'a str,
+    #[serde(rename = "metaCoreUrl")]
+    meta_core_url: &'a str,
+    #[serde(rename = "existingMeta")]
+    existing_meta: &'a BTreeMap<String, String>,
+}
+
+impl Enricher {
+    pub fn new(http: reqwest::Client, cfg: EnrichmentConfig) -> Self {
+        Enricher {
+            http,
+            cfg: Arc::new(cfg),
+        }
+    }
+
+    pub fn meta_core_url(&self) -> &str {
+        &self.cfg.meta_core_url
+    }
+
+    /// `true` if any enrichment plugin is wired (so there's enrichment to drive
+    /// beyond the base-record write).
+    pub fn has_plugins(&self) -> bool {
+        self.cfg.filename_parser_url.is_some() || self.cfg.tmdb_url.is_some()
+    }
+
+    /// Write the feeder's base record into meta-core (merge/upsert) under `cid`.
+    /// Identical shape to the gateway dispatcher's write (provenance + the
+    /// `cids/<cid>` key-set collapse).
+    pub async fn write_base_record(
+        &self,
+        cid: &str,
+        record: &DiscoveryRecord,
+    ) -> anyhow::Result<()> {
+        let prov = Provenance::now(
+            &record.upstream_id,
+            &record.record_id,
+            &self.cfg.gateway_peer,
+        );
+        let body = meta_core::build_metadata_body(record, &prov);
+        meta_core::put_record(&self.http, &self.cfg.meta_core_url, cid, &body).await
+    }
+
+    /// Run the video enrichment pipeline for one resolved CID: filename-parser
+    /// (clean title/year/season/episode) → tmdb (tmdbid/poster/overview). Each
+    /// plugin writes its own fields to meta-core. Best-effort: any plugin
+    /// failure is logged and the pipeline continues (the base record already
+    /// landed, so the item is at worst un-enriched, never lost).
+    pub async fn enrich_video(
+        &self,
+        cid: &str,
+        file_name: &str,
+        base_fields: BTreeMap<String, String>,
+    ) {
+        let mut meta = base_fields;
+
+        // 1. filename-parser → originalTitle / movieYear / videoType / season / episode.
+        if let Some(fp_url) = self.cfg.filename_parser_url.clone() {
+            match self.process(&fp_url, "filename-parser", cid, file_name, &meta).await {
+                Ok(()) => {
+                    // Poll for the merged fields so tmdb gets the clean title.
+                    if let Some(merged) = self
+                        .poll_until_field(cid, "originalTitle", FILENAME_PARSE_POLL_TIMEOUT)
+                        .await
+                    {
+                        meta = merged;
+                    } else {
+                        debug!(
+                            target: "meta-feeder::enrich",
+                            cid, "filename-parser produced no originalTitle within timeout; \
+                                  handing tmdb the base fields"
+                        );
+                    }
+                }
+                Err(e) => warn!(
+                    target: "meta-feeder::enrich",
+                    cid, error = %e, "filename-parser /process failed (non-fatal)"
+                ),
+            }
+        }
+
+        // 2. tmdb → tmdbid / poster / overview / genres (requires fileType=video +
+        //    a clean originalTitle, both now present on `meta`).
+        if let Some(tmdb_url) = self.cfg.tmdb_url.clone() {
+            // Configure the API key before each call — tmdb holds it in memory
+            // only, so this is robust to a tmdb-plugin restart. Cheap (local).
+            if let Err(e) = self.configure_tmdb(&tmdb_url).await {
+                warn!(
+                    target: "meta-feeder::enrich",
+                    cid, error = %e, "tmdb /configure failed (continuing; may soft-skip)"
+                );
+            }
+            if let Err(e) = self.process(&tmdb_url, "tmdb", cid, file_name, &meta).await {
+                warn!(
+                    target: "meta-feeder::enrich",
+                    cid, error = %e, "tmdb /process failed (non-fatal)"
+                );
+            }
+        }
+
+        // 3. opensubtitles → subtitles/<lang3>/<cid> (needs tmdbid/imdbid, which
+        //    tmdb writes async). Poll for tmdbid so the plugin has an id to
+        //    search by, then drive it like any other enrichment plugin.
+        if self.cfg.opensubtitles_url.is_some() {
+            let merged = self
+                .poll_until_field(cid, "tmdbid", TMDB_POLL_TIMEOUT)
+                .await
+                .unwrap_or(meta);
+            self.enrich_subtitles(cid, file_name, &merged).await;
+        }
+    }
+
+    /// Enrich a **bundle** from one torrent (metainfo fan-out): N video files +
+    /// an optional whole-torrent pack record. filename-parser runs on every
+    /// target; tmdb runs **once** on the primary video file and its show-level
+    /// anchor (`tmdbid`/poster/genres/…) is fanned to the sibling files. The
+    /// pack record gets filename-parse only (no tmdb — it's the non-playable
+    /// "release as a unit" search handle, D1). Best-effort throughout.
+    pub async fn enrich_bundle(&self, videos: Vec<EnrichTarget>, pack: Option<EnrichTarget>) {
+        // Pack: filename-parse only, no tmdb.
+        if let Some(p) = pack {
+            self.fire_filename(&p).await;
+        }
+
+        if videos.is_empty() {
+            return;
+        }
+        if videos.len() == 1 {
+            // Degenerate single-video bundle → the plain pipeline (filename → tmdb).
+            let v = &videos[0];
+            self.enrich_video(&v.cid, &v.file_name, v.base.clone()).await;
+            return;
+        }
+
+        // Multi-file: fire filename-parser for every file (fire-and-forget — only
+        // the primary is polled, the rest write async).
+        for v in &videos {
+            self.fire_filename(v).await;
+        }
+
+        // Primary = largest by `sizeByte` (ties → lowest index, i.e. first seen).
+        let primary = pick_primary(&videos);
+        let p = &videos[primary];
+
+        // Poll the primary for filename-parser's clean title, then tmdb it.
+        let merged = self
+            .poll_until_field(&p.cid, "originalTitle", FILENAME_PARSE_POLL_TIMEOUT)
+            .await
+            .unwrap_or_else(|| p.base.clone());
+
+        let Some(tmdb_url) = self.cfg.tmdb_url.clone() else {
+            return; // no tmdb wired → filename-only enrichment, done.
+        };
+        if let Err(e) = self.configure_tmdb(&tmdb_url).await {
+            warn!(target: "meta-feeder::enrich", cid = %p.cid, error = %e, "tmdb /configure failed");
+        }
+        if let Err(e) = self.process(&tmdb_url, "tmdb", &p.cid, &p.file_name, &merged).await {
+            warn!(target: "meta-feeder::enrich", cid = %p.cid, error = %e, "primary tmdb /process failed");
+            return;
+        }
+
+        // Read the resolved anchor back off the primary, then fan it to siblings.
+        let Some(anchor_rec) = self.poll_until_field(&p.cid, "tmdbid", TMDB_POLL_TIMEOUT).await
+        else {
+            debug!(target: "meta-feeder::enrich", cid = %p.cid, "primary produced no tmdbid; nothing to fan");
+            return;
+        };
+        let anchor = extract_anchor(&anchor_rec);
+        if anchor.is_empty() {
+            return;
+        }
+        for (i, v) in videos.iter().enumerate() {
+            if i == primary {
+                continue;
+            }
+            // PUT is merge/upsert — this layers the show-level anchor onto each
+            // file's record without disturbing its per-file fields.
+            if let Err(e) =
+                meta_core::put_record(&self.http, &self.cfg.meta_core_url, &v.cid, &anchor).await
+            {
+                warn!(target: "meta-feeder::enrich", cid = %v.cid, error = %e, "anchor fan PUT failed");
+            }
+        }
+
+        // Subtitles per video: each episode needs its own (its season/episode
+        // differs), but they share the fanned tmdbid. Poll each for tmdbid
+        // (present on the primary, fanned onto the siblings) and drive the
+        // opensubtitles plugin. Best-effort + quota-guarded inside the plugin.
+        if self.cfg.opensubtitles_url.is_some() {
+            for v in &videos {
+                let merged = self
+                    .poll_until_field(&v.cid, "tmdbid", TMDB_POLL_TIMEOUT)
+                    .await
+                    .unwrap_or_else(|| v.base.clone());
+                self.enrich_subtitles(&v.cid, &v.file_name, &merged).await;
+            }
+        }
+    }
+
+    /// Fire filename-parser `/process` for one target (fire-and-forget; the
+    /// plugin merges its fields to meta-core async).
+    async fn fire_filename(&self, t: &EnrichTarget) {
+        if let Some(fp_url) = self.cfg.filename_parser_url.clone() {
+            if let Err(e) = self
+                .process(&fp_url, "filename-parser", &t.cid, &t.file_name, &t.base)
+                .await
+            {
+                warn!(target: "meta-feeder::enrich", cid = %t.cid, error = %e, "filename-parser /process failed");
+            }
+        }
+    }
+
+    /// POST `/process` to a plugin. Returns once the plugin *accepts* the task
+    /// (the actual meta-core write is async on the plugin side; the caller polls
+    /// meta-core for the result when it needs it downstream).
+    async fn process(
+        &self,
+        plugin_url: &str,
+        plugin: &str,
+        cid: &str,
+        file_path: &str,
+        existing_meta: &BTreeMap<String, String>,
+    ) -> anyhow::Result<()> {
+        let url = format!("{}/process", plugin_url.trim_end_matches('/'));
+        let body = ProcessRequest {
+            task_id: format!("{plugin}-{cid}-{}", now_nanos()),
+            cid,
+            file_path,
+            callback_url: &self.cfg.callback_url,
+            meta_core_url: &self.cfg.meta_core_url,
+            existing_meta,
+        };
+        let resp = self.http.post(&url).json(&body).send().await?;
+        if !resp.status().is_success() {
+            let status = resp.status();
+            let text = resp.text().await.unwrap_or_default();
+            anyhow::bail!("{plugin} POST {url} returned {status}: {text}");
+        }
+        Ok(())
+    }
+
+    /// POST `/configure` to the tmdb plugin with the API key + language.
+    async fn configure_tmdb(&self, tmdb_url: &str) -> anyhow::Result<()> {
+        let Some(token) = self.cfg.tmdb_token.clone() else {
+            anyhow::bail!("no TMDB token configured");
+        };
+        let url = format!("{}/configure", tmdb_url.trim_end_matches('/'));
+        let body = serde_json::json!({
+            "config": { "apiKey": token, "language": self.cfg.tmdb_language }
+        });
+        let resp = self.http.post(&url).json(&body).send().await?;
+        if !resp.status().is_success() {
+            let status = resp.status();
+            let text = resp.text().await.unwrap_or_default();
+            anyhow::bail!("tmdb /configure returned {status}: {text}");
+        }
+        Ok(())
+    }
+
+    /// POST `/configure` to the opensubtitles plugin with the API key, account
+    /// credentials, and wanted languages.
+    async fn configure_opensubtitles(&self, url: &str) -> anyhow::Result<()> {
+        let Some(key) = self.cfg.opensubtitles_api_key.clone() else {
+            anyhow::bail!("no OpenSubtitles API key configured");
+        };
+        let cfg_url = format!("{}/configure", url.trim_end_matches('/'));
+        let body = serde_json::json!({
+            "config": {
+                "apiKey": key,
+                "username": self.cfg.opensubtitles_username,
+                "password": self.cfg.opensubtitles_password,
+                "languages": self.cfg.opensubtitles_languages,
+            }
+        });
+        let resp = self.http.post(&cfg_url).json(&body).send().await?;
+        if !resp.status().is_success() {
+            let status = resp.status();
+            let text = resp.text().await.unwrap_or_default();
+            anyhow::bail!("opensubtitles /configure returned {status}: {text}");
+        }
+        Ok(())
+    }
+
+    /// Drive the opensubtitles plugin for one video CID. Needs a `tmdbid` or
+    /// `imdbid` in `meta` to search by (the plugin reads them from `existingMeta`
+    /// and writes the `subtitles/<lang3>/<cid>` key-set straight to meta-core).
+    /// Best-effort: any failure is logged and swallowed.
+    async fn enrich_subtitles(&self, cid: &str, file_name: &str, meta: &BTreeMap<String, String>) {
+        let Some(url) = self.cfg.opensubtitles_url.clone() else {
+            return;
+        };
+        if !meta.contains_key("tmdbid") && !meta.contains_key("imdbid") {
+            debug!(
+                target: "meta-feeder::enrich",
+                cid, "no tmdbid/imdbid resolved; skipping opensubtitles"
+            );
+            return;
+        }
+        if let Err(e) = self.configure_opensubtitles(&url).await {
+            warn!(
+                target: "meta-feeder::enrich",
+                cid, error = %e, "opensubtitles /configure failed (continuing; may soft-skip)"
+            );
+        }
+        if let Err(e) = self.process(&url, "opensubtitles", cid, file_name, meta).await {
+            warn!(
+                target: "meta-feeder::enrich",
+                cid, error = %e, "opensubtitles /process failed (non-fatal)"
+            );
+        }
+    }
+
+    /// Poll `GET /meta/{cid}` until `field` is present (non-empty) or `timeout`
+    /// elapses; returns the merged field map on success.
+    async fn poll_until_field(
+        &self,
+        cid: &str,
+        field: &str,
+        timeout: Duration,
+    ) -> Option<BTreeMap<String, String>> {
+        let deadline = SystemTime::now() + timeout;
+        loop {
+            match meta_core::get_record(&self.http, &self.cfg.meta_core_url, cid).await {
+                Ok(Some(fields)) if fields.get(field).is_some_and(|v| !v.is_empty()) => {
+                    return Some(fields);
+                }
+                Ok(_) => {}
+                Err(e) => debug!(
+                    target: "meta-feeder::enrich",
+                    cid, error = %e, "poll get_record failed"
+                ),
+            }
+            if SystemTime::now() >= deadline {
+                return None;
+            }
+            tokio::time::sleep(POLL_INTERVAL).await;
+        }
+    }
+}
+
+fn now_nanos() -> u128 {
+    SystemTime::now()
+        .duration_since(UNIX_EPOCH)
+        .map(|d| d.as_nanos())
+        .unwrap_or(0)
+}
+
+/// Pick the primary video file index: largest by `sizeByte`, ties broken toward
+/// the first (lowest index). Falls back to 0 for an all-unsized bundle.
+fn pick_primary(videos: &[EnrichTarget]) -> usize {
+    videos
+        .iter()
+        .enumerate()
+        .max_by_key(|(i, v)| {
+            let size = v.base.get("sizeByte").and_then(|s| s.parse::<u64>().ok()).unwrap_or(0);
+            // larger size wins; on a tie the smaller index wins (Reverse).
+            (size, std::cmp::Reverse(*i))
+        })
+        .map(|(i, _)| i)
+        .unwrap_or(0)
+}
+
+/// Project a resolved record down to the show-level anchor fields that are safe
+/// to copy to sibling files (see [`ANCHOR_EXACT`] / [`ANCHOR_PREFIXES`]).
+fn extract_anchor(fields: &BTreeMap<String, String>) -> BTreeMap<String, String> {
+    fields
+        .iter()
+        .filter(|(k, _)| {
+            ANCHOR_EXACT.contains(&k.as_str())
+                || ANCHOR_PREFIXES.iter().any(|p| k.starts_with(p))
+        })
+        .map(|(k, v)| (k.clone(), v.clone()))
+        .collect()
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn from_env_requires_meta_core_url() {
+        // Not set in the test env → None (legacy gateway-stores path).
+        // (We don't mutate process env here to avoid cross-test races; this just
+        // documents the contract.)
+        assert!(EnrichmentConfig::from_env().is_none() || EnrichmentConfig::from_env().is_some());
+    }
+
+    fn tgt(cid: &str, size: u64) -> EnrichTarget {
+        EnrichTarget {
+            cid: cid.into(),
+            file_name: cid.into(),
+            base: BTreeMap::from_iter([("sizeByte".to_string(), size.to_string())]),
+        }
+    }
+
+    #[test]
+    fn pick_primary_is_largest_then_first() {
+        let v = vec![tgt("a", 100), tgt("b", 900), tgt("c", 900), tgt("d", 50)];
+        // 'b' and 'c' tie at 900 → lowest index ('b', idx 1) wins.
+        assert_eq!(pick_primary(&v), 1);
+    }
+
+    #[test]
+    fn pick_primary_all_unsized_defaults_first() {
+        let v = vec![
+            EnrichTarget { cid: "a".into(), file_name: "a".into(), base: BTreeMap::new() },
+            EnrichTarget { cid: "b".into(), file_name: "b".into(), base: BTreeMap::new() },
+        ];
+        assert_eq!(pick_primary(&v), 0);
+    }
+
+    #[test]
+    fn extract_anchor_keeps_show_level_drops_per_file() {
+        let rec = BTreeMap::from_iter([
+            ("tmdbid".to_string(), "10378".to_string()),
+            ("imdbid".to_string(), "tt1254207".to_string()),
+            ("poster".to_string(), "bafkPOSTER".to_string()),
+            ("genres".to_string(), "Animation|Comedy".to_string()),
+            ("plot/eng".to_string(), "a plot".to_string()),
+            ("tags".to_string(), "tmdb-verified".to_string()),
+            // per-file — must NOT be fanned:
+            ("originalTitle".to_string(), "Big Buck Bunny".to_string()),
+            ("season".to_string(), "1".to_string()),
+            ("episode".to_string(), "3".to_string()),
+            ("fileName".to_string(), "ep3.mkv".to_string()),
+        ]);
+        let a = extract_anchor(&rec);
+        assert!(a.contains_key("tmdbid") && a.contains_key("poster") && a.contains_key("plot/eng"));
+        assert!(a.contains_key("genres") && a.contains_key("tags") && a.contains_key("imdbid"));
+        assert!(!a.contains_key("originalTitle"), "originalTitle is per-file");
+        assert!(!a.contains_key("season") && !a.contains_key("episode"));
+        assert!(!a.contains_key("fileName"));
+    }
+}

src/lang.rs

@@ -0,0 +1,81 @@
+//! Language-code normalization — ISO 639 alias folding, **not** filename
+//! parsing.
+//!
+//! This lives apart from [`crate::filename_meta`] on purpose: it doesn't read a
+//! release title, it canonicalizes a *language code* (an indexer's declared
+//! language, a query's `languages:` filter, a title-derived stamp) onto the
+//! single ISO 639-2/B alpha-3 vocabulary the rest of the stack compares against.
+//! It is the one piece of the old `filename_meta` module that has no equivalent
+//! in the `metamesh-plugin-filename-parser` plugin — because it isn't filename
+//! parsing — so it stays in Rust while the title-parsing algorithm itself is
+//! owned by the plugin. Callers in the **request hot path** (e.g. the torznab
+//! indexer-language fan-out skip) need it synchronously, with no network hop.
+
+/// Normalize a language code to the ISO 639-2/B alpha-3 vocabulary the stack
+/// emits (`fre`/`ger`/`chi`, **not** the 639-2/T `fra`/`deu`/`zho` nor the
+/// 639-1 two-letter forms), lowercased. This is the space meta-share's
+/// "languages I read" preference uses and that the title-derived language stamps
+/// write, so an operator who declares an indexer's language as `fra`/`de`/`zh`
+/// still lines up with a `fre`/`ger`/`chi` query filter. Unknown /
+/// already-canonical codes pass through lowercased+trimmed unchanged.
+pub fn normalize_lang_code(code: &str) -> String {
+    let c = code.trim().to_ascii_lowercase();
+    let mapped = match c.as_str() {
+        // 639-2/T and 639-1 → 639-2/B for the codes that actually differ.
+        "fra" | "fr" => "fre",
+        "deu" | "de" => "ger",
+        "zho" | "zh" => "chi",
+        "nld" | "nl" => "dut",
+        "ell" | "el" => "gre",
+        "ron" | "ro" => "rum",
+        "slk" | "sk" => "slo",
+        "ces" | "cs" => "cze",
+        // 639-1 → 639-2 for the rest of the language-tag output space (these
+        // share the same /B and /T alpha-3, so only the two-letter form maps).
+        "en" => "eng",
+        "ja" => "jpn",
+        "it" => "ita",
+        "es" => "spa",
+        "pt" => "por",
+        "ko" => "kor",
+        "ru" => "rus",
+        "pl" => "pol",
+        "hu" => "hun",
+        "uk" => "ukr",
+        "bg" => "bul",
+        "sv" => "swe",
+        "no" => "nor",
+        "da" => "dan",
+        "fi" => "fin",
+        "tr" => "tur",
+        "ar" => "ara",
+        "hi" => "hin",
+        "ta" => "tam",
+        "te" => "tel",
+        "ml" => "mal",
+        "vi" => "vie",
+        "th" => "tha",
+        _ => return c,
+    };
+    mapped.to_string()
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn normalize_lang_maps_to_639_2b_vocabulary() {
+        // 639-2/T and 639-1 spellings collapse onto the /B forms the stack uses.
+        assert_eq!(normalize_lang_code("fra"), "fre");
+        assert_eq!(normalize_lang_code("FR"), "fre");
+        assert_eq!(normalize_lang_code("deu"), "ger");
+        assert_eq!(normalize_lang_code("zh"), "chi");
+        assert_eq!(normalize_lang_code("nld"), "dut");
+        // Already-canonical / unknown codes pass through trimmed + lowercased.
+        assert_eq!(normalize_lang_code("  ENG "), "eng");
+        assert_eq!(normalize_lang_code("fre"), "fre");
+        assert_eq!(normalize_lang_code("mul"), "mul");
+        assert_eq!(normalize_lang_code("xyz"), "xyz");
+    }
+}

src/lib.rs

@@ -0,0 +1,49 @@
+//! `meta-feeder-sdk` — the source-agnostic foundation shared by the gateway
+//! core and every feeder sidecar binary.
+//!
+//! A *feeder* implements [`FeederPlugin`] (find records, fetch bytes) for one
+//! or more upstreams, and [`serve_feeders`] exposes them over the feeder HTTP
+//! contract. The gateway core consumes that contract via its
+//! `RemoteFeederPlugin` and keeps the libp2p wire, the bitswap blockstore, the
+//! hashing-into-the-blockstore, and the meta-core store-back to itself.
+//!
+//! Deliberately libp2p-free and blockstore-free — see this crate's `Cargo.toml`.
+
+// `redb::Error` is a large enum; the cache wrappers (`cache.rs`) return it
+// directly rather than boxing on every embedded-DB call. Boxing each would be
+// pure noise for a single-process store, so silence the lint crate-wide.
+#![allow(clippy::result_large_err)]
+
+/// pcs-convention default meta-core root a self-publishing feeder targets when
+/// neither its dashboard config nor the `META_CORE_URL` env seed sets one. Keeps
+/// the modular storage seam out of compose: a standard install just works; a
+/// non-standard meta-core is set in the feeder's config UI. Matches the
+/// `metacore-app` service the AppStore feeder apps ship on the shared network.
+pub const DEFAULT_META_CORE_URL: &str = "http://metacore-app:9000";
+
+pub mod cache;
+pub mod common;
+pub mod config;
+pub mod enrich;
+pub mod filename_meta;
+pub mod hash;
+pub mod lang;
+pub mod meta_core;
+pub mod plugin;
+pub mod query;
+pub mod query_eval;
+pub mod serve;
+pub mod types;
+
+pub use config::{ConfigField, ConfigSchema, FieldKind};
+pub use enrich::{EnrichTarget, EnrichmentConfig, Enricher};
+pub use meta_core::FeederStore;
+pub use plugin::{
+    upstream_id_field, ConfigError, FeederPlugin, HashKind, HashOutcome, PluginRegistry,
+};
+pub use query::{GatewayQuery, GatewaySearchEvent, GatewayWireError, Negation, RangeFilter};
+pub use serve::{
+    configure_plugins, router, serve_feeders, ComputeRequest, ComputeResponse, HashKindDto,
+    HealthResponse, ManifestResponse, OutcomeDto, PluginManifest, QueryRequest, QueryResponse,
+};
+pub use types::{ByteStream, DiscoveryId, DiscoveryRecord, GatewayError, Hash, PluginHealth};

src/meta_core.rs

@@ -0,0 +1,335 @@
+//! Lightweight meta-core write/read client for feeders that **self-publish**.
+//!
+//! Post-"smart feeder / dumb gateway" split: a feeder given a `META_CORE_URL`
+//! writes its own base record into meta-core instead of returning it for the
+//! gateway dispatcher to store. This keeps the gateway a pure aggregator +
+//! request router; the feeder owns the full record lifecycle for its upstream.
+//!
+//! The write shape is **byte-for-byte the same** as the gateway's
+//! `meta_core::build_metadata_body` (`crates/meta-gateway/src/meta_core.rs`):
+//! `cid_*` fields collapse to the `cids/<cid> = "true"` key-set, and a
+//! `provenance` JSON blob is stamped. Keeping them identical means a record
+//! written by the feeder is indistinguishable from one the dispatcher wrote —
+//! the meta-share ingester, meta-watch, and ranking all behave the same.
+//!
+//! `PUT /api/metadata/{cid}` is merge/upsert (confirmed: meta-core
+//! `SetMetadataFlat` sets only the fields in the payload, never deletes), so the
+//! feeder's base write and the enrichment plugins' later `PATCH /meta/{cid}`
+//! merges accumulate on the same `/file/{cid}` hash.
+
+use std::collections::BTreeMap;
+use std::time::{SystemTime, UNIX_EPOCH};
+
+use serde::Deserialize;
+use tracing::warn;
+
+use crate::plugin::{HashKind, HashOutcome};
+use crate::types::{DiscoveryRecord, Hash};
+
+/// Provenance recorded on every gateway-acquired record. Mirrors the gateway
+/// dispatcher's shape so feeder-written and dispatcher-written records are
+/// interchangeable.
+#[derive(Clone, Debug)]
+pub struct Provenance {
+    pub upstream: String,
+    pub record_id: String,
+    /// Stable per-deployment id (the gateway peer this feeder backs, from
+    /// `META_GATEWAY_PEER_ID`, else the feeder hostname). Analytics group by it.
+    pub gateway_peer: String,
+    pub acquired_at: u64,
+}
+
+impl Provenance {
+    /// Build a provenance stamp for `upstream`/`record_id`, stamping "now".
+    pub fn now(upstream: &str, record_id: &str, gateway_peer: &str) -> Self {
+        Provenance {
+            upstream: upstream.to_string(),
+            record_id: record_id.to_string(),
+            gateway_peer: gateway_peer.to_string(),
+            acquired_at: SystemTime::now()
+                .duration_since(UNIX_EPOCH)
+                .map(|d| d.as_secs())
+                .unwrap_or(0),
+        }
+    }
+}
+
+/// JSON-stringified provenance value. Same key set + `"source":"gateway"` as the
+/// gateway dispatcher (`crates/meta-gateway/src/meta_core.rs::provenance_to_json`).
+pub fn provenance_to_json(p: &Provenance) -> String {
+    serde_json::to_string(&serde_json::json!({
+        "source":      "gateway",
+        "upstream":    p.upstream,
+        "recordId":    p.record_id,
+        "gatewayPeer": p.gateway_peer,
+        "acquiredAt":  p.acquired_at,
+    }))
+    .expect("static JSON shape — serialisation is infallible")
+}
+
+/// Build the flat meta-core PUT body from a [`DiscoveryRecord`] + provenance.
+///
+/// Identical transform to the gateway dispatcher: any `cid_*` field becomes a
+/// `cids/<value> = "true"` key-set member (the CID is self-describing — the
+/// algorithm is the multicodec; see METADATA_KEYS.md §2/§14.13), everything else
+/// passes through, and `provenance` is stamped last (overriding any plugin-set
+/// value).
+pub fn build_metadata_body(
+    record: &DiscoveryRecord,
+    provenance: &Provenance,
+) -> BTreeMap<String, String> {
+    let mut body: BTreeMap<String, String> = BTreeMap::new();
+    for (k, v) in &record.fields {
+        if k.starts_with("cid_") && !v.is_empty() {
+            body.insert(format!("cids/{v}"), "true".to_string());
+        } else {
+            body.insert(k.clone(), v.clone());
+        }
+    }
+    body.insert("provenance".to_string(), provenance_to_json(provenance));
+    body
+}
+
+/// `PUT /api/metadata/{cid}` — write (merge/upsert) the record body into
+/// meta-core. `base_url` is the meta-core root (e.g. `http://…-core:9000`).
+pub async fn put_record(
+    http: &reqwest::Client,
+    base_url: &str,
+    cid: &str,
+    body: &BTreeMap<String, String>,
+) -> anyhow::Result<()> {
+    let url = format!("{}/api/metadata/{}", base_url.trim_end_matches('/'), cid);
+    let resp = http.put(&url).json(body).send().await?;
+    let status = resp.status();
+    if !status.is_success() {
+        let text = resp.text().await.unwrap_or_default();
+        anyhow::bail!("meta-core PUT {url} returned {status}: {text}");
+    }
+    Ok(())
+}
+
+/// Shape of meta-core's `GET /meta/{cid}` response (`{ hashId, metadata }`).
+#[derive(Debug, Deserialize)]
+struct MetaGetResponse {
+    #[serde(default)]
+    metadata: Option<BTreeMap<String, String>>,
+}
+
+/// `GET /meta/{cid}` — read the current flat field map for a record, or `None`
+/// when meta-core has no record yet (404). Used to read back a plugin's merged
+/// fields (e.g. filename-parser's `originalTitle`/`movieYear`) before handing
+/// them to the next plugin in the pipeline.
+pub async fn get_record(
+    http: &reqwest::Client,
+    base_url: &str,
+    cid: &str,
+) -> anyhow::Result<Option<BTreeMap<String, String>>> {
+    let url = format!("{}/meta/{}", base_url.trim_end_matches('/'), cid);
+    let resp = http.get(&url).send().await?;
+    if resp.status() == reqwest::StatusCode::NOT_FOUND {
+        return Ok(None);
+    }
+    if !resp.status().is_success() {
+        anyhow::bail!("meta-core GET {url} returned {}", resp.status());
+    }
+    let parsed: MetaGetResponse = resp.json().await?;
+    Ok(parsed.metadata)
+}
+
+/// Self-publishing store for feeders that own their record lifecycle (D4):
+/// the feeder writes its own **metadata-only** records to meta-core and returns
+/// sparse outcomes so the gateway dispatcher skips them; the meta-share ingester
+/// Kamilata-propagates them.
+///
+/// **Byte outcomes are deliberately NOT self-published.** A feeder-side WebDAV
+/// write to the gateway core would be seeded by nobody: the gateway core runs
+/// with `ENABLE_FILE_WATCHER=false` (so meta-core emits no `/api/events/files`
+/// for it, and the ingester's `ipfs_seed` — which seeds only watched files —
+/// never sees it), and a sparse outcome makes the gateway skip its own
+/// blockstore seed. So byte-bearing outcomes (torznab full-file / subtitles)
+/// pass through unchanged and the **gateway** continues to WebDAV-PUT + bitswap-
+/// seed them (it's the libp2p/bitswap host). Result: feeder owns the metadata
+/// records (the Kamilata-propagated bulk), gateway owns byte delivery — a clean
+/// split with no seeding regression. Tribler is metadata-only and uses
+/// [`crate::enrich::Enricher`]; this is torznab's record-owning counterpart.
+#[derive(Clone)]
+pub struct FeederStore {
+    http: reqwest::Client,
+    meta_core_url: String,
+    gateway_peer: String,
+}
+
+impl FeederStore {
+    pub fn new(http: reqwest::Client, meta_core_url: String, gateway_peer: String) -> Self {
+        FeederStore {
+            http,
+            meta_core_url: meta_core_url.trim_end_matches('/').to_string(),
+            gateway_peer,
+        }
+    }
+
+    /// Build from the feeder env. `None` when `META_CORE_URL` is unset (the
+    /// feeder then falls back to the legacy "return outcomes, gateway stores"
+    /// path). `gateway_peer` ← `META_GATEWAY_PEER_ID` / `HOSTNAME`.
+    pub fn from_env() -> Option<Self> {
+        let meta_core_url = env_nonempty("META_CORE_URL")?;
+        let gateway_peer = env_nonempty("META_GATEWAY_PEER_ID")
+            .or_else(|| env_nonempty("HOSTNAME"))
+            .unwrap_or_else(|| "gateway-feeder".to_string());
+        let http = crate::common::build_http_client(30, "meta-feeder-store", None);
+        Some(Self::new(http, meta_core_url, gateway_peer))
+    }
+
+    pub fn meta_core_url(&self) -> &str {
+        &self.meta_core_url
+    }
+
+    /// Raw keys containing `contains` (`GET /api/kv/search`). Returns
+    /// `(keys, truncated)`; `truncated` means the server capped the result and
+    /// there may be more.
+    ///
+    /// This is a keyspace scan, so it belongs on rare control-plane paths only —
+    /// today, invalidating the gateway's search-coverage markers when a feeder's
+    /// upstream source set changes. Never call it per search.
+    pub async fn search_keys(&self, contains: &str, limit: usize) -> anyhow::Result<(Vec<String>, bool)> {
+        let url = format!("{}/api/kv/search", self.meta_core_url);
+        let resp = self
+            .http
+            .get(&url)
+            .query(&[("contains", contains), ("limit", &limit.to_string())])
+            .send()
+            .await?;
+        let status = resp.status();
+        if !status.is_success() {
+            anyhow::bail!("meta-core KV search `{contains}` returned {status}");
+        }
+        #[derive(Deserialize)]
+        struct KvSearchResponse {
+            #[serde(default)]
+            keys: Vec<String>,
+            #[serde(default)]
+            truncated: bool,
+        }
+        let body: KvSearchResponse = resp.json().await?;
+        Ok((body.keys, body.truncated))
+    }
+
+    /// Delete one raw KV key (`DELETE /api/kv/value?key=`). A missing key is not
+    /// an error.
+    pub async fn delete_kv(&self, key: &str) -> anyhow::Result<()> {
+        let url = format!("{}/api/kv/value", self.meta_core_url);
+        let resp = self.http.delete(&url).query(&[("key", key)]).send().await?;
+        let status = resp.status();
+        if status.is_success() || status == reqwest::StatusCode::NOT_FOUND {
+            return Ok(());
+        }
+        anyhow::bail!("meta-core KV DELETE {key} returned {status}");
+    }
+
+    /// Self-publish a **metadata-only** outcome to meta-core, returning the
+    /// **sparse** outcome (`record: None`) so the gateway's `(_, None)` branch
+    /// skips it — no double write. Byte outcomes and already-sparse outcomes are
+    /// returned unchanged (the gateway stores + seeds the bytes; see the struct
+    /// docs). On a write failure the original outcome is returned so the gateway
+    /// stores it (graceful degradation, never lost).
+    pub async fn publish(
+        &self,
+        upstream_id: &str,
+        record_id: &str,
+        outcome: HashOutcome,
+    ) -> HashOutcome {
+        // Only self-publish metadata-only outcomes (bytes None, record Some).
+        if outcome.bytes.is_some() || outcome.record.is_none() {
+            return outcome;
+        }
+        let cid = outcome.hash.0.clone();
+        let record = outcome.record.as_ref().expect("record is Some by the guard");
+        match self
+            .store_metadata_only(upstream_id, record_id, &cid, record)
+            .await
+        {
+            Ok(()) => sparse(outcome.hash, outcome.hash_kind),
+            Err(e) => {
+                warn!(target: "meta-feeder::store", cid = %cid, error = %e,
+                      "metadata self-publish failed; falling back to gateway store");
+                outcome
+            }
+        }
+    }
+
+    /// Metadata-only self-publish: `PUT /api/metadata/{cid}` with provenance.
+    async fn store_metadata_only(
+        &self,
+        upstream_id: &str,
+        record_id: &str,
+        cid: &str,
+        record: &DiscoveryRecord,
+    ) -> anyhow::Result<()> {
+        let prov = Provenance::now(upstream_id, record_id, &self.gateway_peer);
+        let body = build_metadata_body(record, &prov);
+        put_record(&self.http, &self.meta_core_url, cid, &body).await
+    }
+}
+
+fn sparse(hash: Hash, hash_kind: HashKind) -> HashOutcome {
+    HashOutcome {
+        hash,
+        hash_kind,
+        bytes: None,
+        record: None,
+        file_extension: None,
+    }
+}
+
+fn env_nonempty(key: &str) -> Option<String> {
+    std::env::var(key)
+        .ok()
+        .map(|s| s.trim().to_string())
+        .filter(|s| !s.is_empty())
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    fn rec() -> DiscoveryRecord {
+        DiscoveryRecord {
+            upstream_id: "tribler".into(),
+            record_id: "abc".into(),
+            fields: BTreeMap::from_iter([
+                ("title".into(), "Big Buck Bunny".into()),
+                ("cid_btih_v1_file".into(), "bafkPERFILE".into()),
+            ]),
+        }
+    }
+
+    #[test]
+    fn provenance_shape_matches_gateway() {
+        let p = Provenance {
+            upstream: "tribler".into(),
+            record_id: "abc".into(),
+            gateway_peer: "metagateway-tribler".into(),
+            acquired_at: 1_747_504_000,
+        };
+        let v: serde_json::Value = serde_json::from_str(&provenance_to_json(&p)).unwrap();
+        assert_eq!(v["source"], "gateway");
+        assert_eq!(v["upstream"], "tribler");
+        assert_eq!(v["recordId"], "abc");
+        assert_eq!(v["gatewayPeer"], "metagateway-tribler");
+        assert_eq!(v["acquiredAt"], 1_747_504_000_u64);
+    }
+
+    #[test]
+    fn body_collapses_cid_fields_and_stamps_provenance() {
+        let p = Provenance::now("tribler", "abc", "peer");
+        let body = build_metadata_body(&rec(), &p);
+        assert_eq!(body.get("title").map(String::as_str), Some("Big Buck Bunny"));
+        // cid_* collapsed to cids/<value>=true; no cid_* survives.
+        assert!(body.keys().all(|k| !k.starts_with("cid_")));
+        assert_eq!(
+            body.get("cids/bafkPERFILE").map(String::as_str),
+            Some("true")
+        );
+        assert!(body.contains_key("provenance"));
+    }
+}

src/plugin.rs

@@ -0,0 +1,258 @@
+//! The `FeederPlugin` trait + supporting types.
+//!
+//! A feeder plugin bridges one external upstream (`gutenberg`, `arxiv`,
+//! `torznab`, …) into the MetaMesh network. It **finds** records and
+//! **fetches** bytes; it does NOT hash-into-a-blockstore, store back into
+//! meta-core, or speak libp2p — those stay in the gateway core. This is why
+//! `FeederPlugin` has no `set_blockstore` / `set_tmdb_budget` hooks (the
+//! gateway's `GatewayPlugin` carried them): preview-seeding moves to the core,
+//! and a feeder that needs a TMDB budget owns it internally.
+//!
+//! The `serve_feeders` harness ([`crate::serve`]) wraps any set of
+//! `FeederPlugin`s in the feeder HTTP contract; the gateway core's
+//! `RemoteFeederPlugin` is the matching HTTP client.
+
+use std::collections::HashMap;
+use std::path::Path;
+
+use async_trait::async_trait;
+use futures::stream::BoxStream;
+
+// Re-exported so plugins can `use meta_feeder_sdk::plugin::GatewayQuery` (the
+// gateway's original `plugin.rs` re-exported it the same way).
+pub use crate::query::GatewayQuery;
+use crate::query::GatewaySearchEvent;
+use crate::types::{ByteStream, DiscoveryRecord, GatewayError, Hash, PluginHealth};
+
+/// One element of what [`FeederPlugin::compute_outcomes`] returns.
+///
+/// The `hash` is the value shipped to the gateway core. The other fields are
+/// signals the core's auto-store uses to persist the content into meta-core.
+/// The core's three-branch auto-store routes on `(bytes, record)`:
+/// - `(Some, Some)` — full store: WebDAV PUT + metadata PUT with `filePath`.
+/// - `(None, Some)` — metadata-only PUT (no local bytes; e.g. torznab samples
+///   the middle 1 MiB of a multi-GiB video and surfaces only the record).
+/// - `(_, None)` — skip. Cache hits land here.
+///
+/// `file_extension` MUST be `None` when `bytes` is `None`.
+#[derive(Debug)]
+pub struct HashOutcome {
+    pub hash: Hash,
+    /// Which hash family this CID belongs to. Drives the core's routing —
+    /// the bitswap blockstore seed only fires for `Sha2_256`.
+    pub hash_kind: HashKind,
+    pub bytes: Option<bytes::Bytes>,
+    pub record: Option<DiscoveryRecord>,
+    /// File extension to append when naming the WebDAV-side blob (e.g.
+    /// `"epub"`). No leading dot. MUST be `None` when `bytes` is `None`.
+    pub file_extension: Option<String>,
+}
+
+/// Hash family discriminator on [`HashOutcome`].
+///
+/// - `Midhash256` — size-prefix-plus-middle-1MB-sample, custom multicodec
+///   `0x1000`. Fast, MetaMesh-internal, not retrievable via public IPFS.
+/// - `Sha2_256` — standard IPFS CIDv1 over full bytes. Retrievable via bitswap
+///   once the bytes are in the core's blockstore. What every shipping plugin
+///   today emits.
+/// - `BtV1File` — a single file inside a BitTorrent v1 torrent, custom
+///   multicodec `0x1001`. Locator, not content hash: opaque to bitswap.
+/// - `NzbRelease` — a Usenet release (a Newznab listing), custom multicodec
+///   `nzb-release` `0x1005`. Self-describing locator: the cid embeds `{host,
+///   id}` in an identity multihash, opaque to bitswap and redeemed to bytes
+///   only by a credentialed meta-share peer, which decodes the locator from the
+///   cid and grabs the `.nzb` via `t=get` — no KV side-table.
+/// - `CardLocator` — the identity of a *work* (a series, a film) as published by
+///   a metadata bridge, custom multicodec `0x1007`. The only family with **no
+///   bytes behind it at all**: the record IS the payload. Always paired with
+///   `bytes: None`, so it lands in the `(None, Some)` metadata-only branch
+///   above. Opaque to bitswap, and deliberately so — there is nothing to seed.
+/// - `NzbPosting` — a Usenet posting we **scanned ourselves**, custom multicodec
+///   `nzb-posting` `0x1003`. A content-derived digest over the article
+///   Message-ID set (not a locator: no host is embedded), so any peer with a
+///   plain NNTP provider can fetch it — no `IndexerCred`. Opaque to bitswap: the
+///   digest is over the id set, not over any block, so the `.nzb` manifest
+///   travels separately as an ordinary sha2-256 cid in the record's `manifest`
+///   field. Produced by `hash::compute_nzb_posting_cid`.
+/// - `YtVideo` — a **delegated-playback** reference, custom multicodec
+///   `yt-video` `0x1008`. Like `CardLocator` it is always paired with
+///   `bytes: None` and lands in the `(None, Some)` metadata-only branch, but it
+///   means something stronger than "no bytes yet": the bytes **exist and are
+///   permanently someone else's**. Nothing is fetched, seeded or
+///   content-addressed, and meta-share's byte path REFUSES the cid with a `400`
+///   rather than 404ing. Produced by `hash::compute_yt_video_cid`.
+#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+pub enum HashKind {
+    /// Reserved: no feeder currently emits midhash256 outcomes, but the family
+    /// is real across meta-core / meta-share, so the variant stays.
+    #[allow(dead_code)]
+    Midhash256,
+    Sha2_256,
+    BtV1File,
+    NzbRelease,
+    CardLocator,
+    NzbPosting,
+    YtVideo,
+}
+
+/// Startup-only configuration error returned by [`FeederPlugin::configure`].
+#[derive(Debug, thiserror::Error)]
+pub enum ConfigError {
+    #[error("plugin {plugin}: required config missing: {what}")]
+    MissingConfig {
+        plugin: &'static str,
+        /// Human-readable description of the missing setting and where to
+        /// supply it. Used by the harness's soft-skip warning.
+        what: &'static str,
+    },
+
+    #[error("plugin {plugin}: cache dir setup failed: {source}")]
+    CacheSetup {
+        plugin: &'static str,
+        #[source]
+        source: std::io::Error,
+    },
+
+    #[error("plugin {plugin}: {source}")]
+    Other {
+        plugin: &'static str,
+        #[source]
+        source: anyhow::Error,
+    },
+}
+
+/// Canonical field name for an upstream's stable per-record identifier.
+/// Every plugin's `DiscoveryRecord.fields` MUST include this key
+/// (`gutenbergid:11`, `tmdbid:31910`, `arxivid:2106.07447`). The rule is
+/// `format!("{upstream_id}id")` — lowercase, no separator.
+pub fn upstream_id_field(upstream_id: &str) -> String {
+    format!("{upstream_id}id")
+}
+
+/// Key-set prefix for the provenance `source/<label>` field (METADATA_KEYS §5).
+/// Each member is its own hash field (`source/gateway:nyaa.si = "true"`) so two
+/// producers that reach the same content by different routes union without a
+/// last-writer-wins clobber. The `<label>` uses `:` internally (not `/`, which
+/// is the key-set path separator) — e.g. `gateway:nyaa.si`, `gateway:tribler`.
+pub const SOURCE_KEYSET_PREFIX: &str = "source/";
+
+/// Stamp the SDK's default provenance member — `source/gateway:<upstream_id>` —
+/// onto a record's fields, but **only if it carries no `source/*` member yet**.
+/// This gives every gateway hit a provenance label for free (so meta-watch never
+/// falls back to "unknown" for a feeder record), while a plugin that knows a
+/// finer origin (torznab → the specific Prowlarr indexer) stamps its own flat
+/// `source/*` facets first (`source/gateway`, `source/<protocol>`,
+/// `source/<indexer-slug>`) and this default then no-ops.
+pub fn stamp_default_source(
+    fields: &mut std::collections::BTreeMap<String, String>,
+    upstream_id: &str,
+) {
+    if fields.keys().any(|k| k.starts_with(SOURCE_KEYSET_PREFIX)) {
+        return;
+    }
+    fields.insert(
+        format!("{SOURCE_KEYSET_PREFIX}gateway:{upstream_id}"),
+        "true".to_string(),
+    );
+}
+
+/// Static plugin contract. Each enabled `upstream_id` is implemented by
+/// exactly one `Box<dyn FeederPlugin>`. Lives behind `&self` in steady state —
+/// called concurrently, owns any interior mutability for caches.
+///
+/// **Field-naming convention.** Every record a plugin returns MUST include the
+/// canonical `<upstream_id>id` field — see [`upstream_id_field`].
+#[async_trait]
+pub trait FeederPlugin: Send + Sync + 'static {
+    fn upstream_id(&self) -> &'static str;
+
+    fn configure(&mut self, cache_dir: &Path) -> Result<(), ConfigError>;
+
+    async fn handle_query(
+        &self,
+        query: &GatewayQuery,
+        max_results: usize,
+    ) -> Result<Vec<DiscoveryRecord>, GatewayError>;
+
+    /// Streaming variant of [`handle_query`]. The default impl collects
+    /// [`handle_query`] and replays it as `Base*` + `Done` — correct for every
+    /// plugin with no incremental enrichment (gutenberg, arxiv, …). torznab
+    /// overrides it to decouple base records from rate-limited TMDB enrichment.
+    async fn handle_query_stream(
+        &self,
+        query: &GatewayQuery,
+        max_results: usize,
+    ) -> Result<BoxStream<'static, GatewaySearchEvent>, GatewayError> {
+        let records = self.handle_query(query, max_results).await?;
+        let events = records
+            .into_iter()
+            .map(GatewaySearchEvent::Base)
+            .chain(std::iter::once(GatewaySearchEvent::Done));
+        Ok(Box::pin(futures::stream::iter(events)))
+    }
+
+    /// Resolve `record_id` into one or more content-addressed outcomes.
+    ///
+    /// - `Err(_)` — the upstream record itself is unresolvable.
+    /// - `Ok(vec![])` — resolved but yielded zero outcomes.
+    /// - `Ok(partial_vec)` — bundle-success: per-sibling failures are
+    ///   best-effort (log + drop), surface whatever succeeded.
+    async fn compute_outcomes(&self, record_id: &str) -> Result<Vec<HashOutcome>, GatewayError>;
+
+    async fn handle_fetch(&self, _record_id: &str) -> Result<Option<ByteStream>, GatewayError> {
+        Ok(None)
+    }
+
+    fn health(&self) -> PluginHealth {
+        PluginHealth::Ok
+    }
+
+    fn served_file_types(&self) -> &'static [&'static str] {
+        &[]
+    }
+
+    fn served_content_kinds(&self) -> &'static [&'static str] {
+        &[]
+    }
+
+    /// Self-describing config schema. The feeder SDK serves this at
+    /// `GET /config/schema` and renders a generic form from it — the gateway and
+    /// UI carry no per-plugin field knowledge. Default: no configuration.
+    fn config_schema(&self) -> crate::config::ConfigSchema {
+        crate::config::ConfigSchema::default()
+    }
+
+    /// The plugin's current *effective* config as JSON, **unredacted** (secrets
+    /// included). The SDK redacts it before serving `GET /config/values` and uses
+    /// it as the merge base on the first save (before any `config.json` exists).
+    /// Default: empty object. Implementors should mirror the keys in
+    /// [`config_schema`](FeederPlugin::config_schema).
+    fn config_values(&self) -> serde_json::Value {
+        serde_json::json!({})
+    }
+
+    async fn get_blob(&self, _cid: &str) -> Option<Vec<u8>> {
+        None
+    }
+}
+
+/// Static plugin registry. Built once at startup; read-only thereafter.
+/// Keyed by `upstream_id`.
+pub type PluginRegistry = HashMap<&'static str, Box<dyn FeederPlugin>>;
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn config_error_messages_include_plugin_name() {
+        let e = ConfigError::MissingConfig {
+            plugin: "scihub",
+            what:
+                "mirrors (set them in the dashboard or gateway-config.json plugins.scihub.mirrors)",
+        };
+        let msg = e.to_string();
+        assert!(msg.contains("scihub"));
+        assert!(msg.contains("mirrors"));
+    }
+}

src/query.rs

@@ -0,0 +1,147 @@
+//! Structured query envelope + streaming-search event + wire-error types,
+//! shared by feeders (their HTTP contract) and the gateway core (its libp2p
+//! wire). These are pure serde data types — no libp2p, no transport.
+//!
+//! On the core side, `protocol.rs` re-uses these exact structs as the bincode
+//! wire shape; the `wire_parity_*` tests there pin the byte encoding. Keep
+//! field order / variant order / derive shape stable.
+
+use std::collections::BTreeMap;
+
+use serde::{Deserialize, Serialize};
+
+use crate::types::{DiscoveryRecord, GatewayError};
+
+/// Structured query envelope. Gateway plugins do best-effort pushdown to
+/// upstream APIs with native query languages (`torznab cat=movie`,
+/// `arxiv id_list=`).
+///
+/// **Authority rule:** `filters` / `ranges` / `negations` are authoritative;
+/// `raw_text` is informational. A plugin that consumes both will double-filter
+/// and under-match — pick one source per filter; structured wins.
+#[derive(Clone, Debug, PartialEq, Eq, Serialize, Deserialize)]
+pub struct GatewayQuery {
+    /// Original user text (e.g. `"naruto contentKind:movie imdbid:tt0903747"`).
+    /// Verbatim — never mutated by the conversion.
+    pub raw_text: String,
+
+    /// Bare-word leaves only, space-joined. The plugin's primary `q=` input
+    /// for upstream search APIs that take a single search box.
+    pub free_text: String,
+
+    /// Structured filters keyed by field name (raw, unstemmed values).
+    /// Multiple values per key = OR within a key; AND across keys.
+    pub filters: BTreeMap<String, Vec<String>>,
+
+    /// Numeric range filters (e.g. `movieYear:2020..2024`). Both bounds
+    /// optional → unbounded on that side.
+    pub ranges: Vec<RangeFilter>,
+
+    /// Negation filters (e.g. `NOT genres:horror`, bare `NOT word`).
+    pub negations: Vec<Negation>,
+}
+
+/// Numeric range filter inside [`GatewayQuery::ranges`]. Both bounds are
+/// `Option<i64>` so open-ended ranges drop one bound to `None`.
+#[derive(Clone, Debug, PartialEq, Eq, Serialize, Deserialize)]
+pub struct RangeFilter {
+    pub field: String,
+    pub lo: Option<i64>,
+    pub hi: Option<i64>,
+}
+
+/// Negation entry inside [`GatewayQuery::negations`]. `field` is `Some(name)`
+/// for typed negations (`NOT genres:horror`), `None` for bare-word negation.
+#[derive(Clone, Debug, PartialEq, Eq, Serialize, Deserialize)]
+pub struct Negation {
+    pub field: Option<String>,
+    pub value: String,
+}
+
+impl GatewayQuery {
+    /// Bare-text input to hand to a free-form upstream search API. Falls back
+    /// to `"*"` when the conversion produced no free-text leaves so upstreams
+    /// that 4xx on empty search return their top-ranked results instead.
+    pub fn free_text_or_star(&self) -> &str {
+        if self.free_text.trim().is_empty() {
+            "*"
+        } else {
+            self.free_text.as_str()
+        }
+    }
+
+    /// Construct a free-text-only `GatewayQuery` for in-process use (tests,
+    /// debug routes). `raw_text` == `free_text`; structured fields stay empty.
+    pub fn from_free_text(text: impl Into<String>) -> Self {
+        let text = text.into();
+        Self {
+            raw_text: text.clone(),
+            free_text: text,
+            filters: BTreeMap::new(),
+            ranges: Vec::new(),
+            negations: Vec::new(),
+        }
+    }
+}
+
+/// One frame in the streaming Search response.
+///
+/// A plugin emits `Base` records as soon as they're discovered, then
+/// best-effort `EnrichPatch`/`Drop` events as enrichment lands, then a
+/// terminal `Done`. The default `handle_query_stream` collects `handle_query`
+/// and replays it as `Base*` + `Done`.
+#[derive(Clone, Debug, PartialEq, Eq, Serialize, Deserialize)]
+pub enum GatewaySearchEvent {
+    /// An un-enriched discovery record.
+    Base(DiscoveryRecord),
+    /// Incremental enrichment for a previously-sent `Base`, keyed by
+    /// `record_id`. `set` fields are inserted/overwritten; `remove` deleted.
+    EnrichPatch {
+        record_id: String,
+        set: BTreeMap<String, String>,
+        remove: Vec<String>,
+    },
+    /// Retract a previously-emitted `Base` record entirely.
+    Drop { record_id: String },
+    /// Terminal success — no more frames follow.
+    Done,
+    /// Terminal error — no more frames follow.
+    Error(GatewayWireError),
+}
+
+/// Wire-stable error shape. Distinct from in-process [`GatewayError`] because
+/// adding a variant here is a wire-format change.
+#[derive(Clone, Debug, PartialEq, Eq, Serialize, Deserialize, thiserror::Error)]
+pub enum GatewayWireError {
+    #[error("not found")]
+    NotFound,
+    #[error("rate limited; retry in {retry_after_s}s")]
+    RateLimited { retry_after_s: u32 },
+    #[error("upstream transient: {0}")]
+    UpstreamTransient(String),
+    #[error("upstream permanent: {0}")]
+    UpstreamPermanent(String),
+    /// The protocol was registered but no plugin claims this `upstream_id`.
+    #[error("plugin not loaded")]
+    PluginNotLoaded,
+    /// Internal codec / decode failure on the *receiver* side.
+    #[error("internal: {0}")]
+    Internal(String),
+}
+
+impl From<GatewayError> for GatewayWireError {
+    fn from(e: GatewayError) -> Self {
+        match e {
+            GatewayError::Transient(s) => GatewayWireError::UpstreamTransient(s),
+            GatewayError::Permanent(s) => GatewayWireError::UpstreamPermanent(s),
+            GatewayError::RateLimited { retry_after_s } => {
+                GatewayWireError::RateLimited { retry_after_s }
+            }
+            GatewayError::NotFound => GatewayWireError::NotFound,
+            // Internal errors are never leaked; map to a transient.
+            GatewayError::Internal(_) => {
+                GatewayWireError::UpstreamTransient("internal".to_string())
+            }
+        }
+    }
+}

src/query_eval.rs

@@ -0,0 +1,514 @@
+//! Structured-filter evaluation for gateway records.
+//!
+//! Two pure helpers consuming the [`crate::query::GatewayQuery`] struct:
+//!
+//! - [`record_matches`] — does a single record's `fields` map satisfy the
+//!   query's `filters` + `ranges` + typed `negations`?
+//! - [`query_accepts_plugin`] — could a plugin advertising the given
+//!   `served_file_types` / `served_content_kinds` possibly produce a record
+//!   that satisfies the query? Used by plugins as a cheap early-return.
+//!
+//! The dispatcher applies `record_matches` to every plugin's return value, and
+//! meta-share applies the same algorithm consumer-side to defend against stale
+//! gateway peers — both tiers must agree on outcomes for any (record, query)
+//! pair. See the original gateway crate docs for the full semantics.
+
+use std::collections::BTreeMap;
+
+use crate::query::GatewayQuery;
+
+/// True iff a record's `fields` satisfies every filter, range, and typed
+/// negation in `query`.
+pub fn record_matches(fields: &BTreeMap<String, String>, query: &GatewayQuery) -> bool {
+    for (key, allowed) in &query.filters {
+        if key == "languages" {
+            if !languages_filter_matches(fields, allowed) {
+                return false;
+            }
+            continue;
+        }
+        // `genres` is a key-set too (`genres/<Name> = "true"`, METADATA_KEYS
+        // §`genres/{name}`) on everything the card tier writes. Without this arm
+        // a `genres:` filter looks up a flat `genres` field, finds nothing on a
+        // card, and drops it — so a genre-scoped row would return empty.
+        if key == "genres" {
+            if !genres_filter_matches(fields, allowed) {
+                return false;
+            }
+            continue;
+        }
+        let Some(field_value) = fields.get(key) else {
+            return false;
+        };
+        if !any_csv_value_matches(field_value, allowed) {
+            return false;
+        }
+    }
+
+    for range in &query.ranges {
+        let Some(field_value) = fields.get(&range.field) else {
+            return false;
+        };
+        let Ok(n) = field_value.parse::<i64>() else {
+            return false;
+        };
+        if let Some(lo) = range.lo {
+            if n < lo {
+                return false;
+            }
+        }
+        if let Some(hi) = range.hi {
+            if n > hi {
+                return false;
+            }
+        }
+    }
+
+    for negation in &query.negations {
+        let Some(name) = negation.field.as_deref() else {
+            // Bare-word negation — not enforced here.
+            continue;
+        };
+        let Some(field_value) = fields.get(name) else {
+            // Missing field ⇒ negation passes (nothing to exclude).
+            continue;
+        };
+        if any_csv_value_matches(field_value, std::slice::from_ref(&negation.value)) {
+            return false;
+        }
+    }
+
+    true
+}
+
+/// True iff a plugin advertising the given `served_file_types` /
+/// `served_content_kinds` could possibly produce a record satisfying
+/// `query.filters["fileType" | "contentKind"]`.
+pub fn query_accepts_plugin(
+    query: &GatewayQuery,
+    served_file_types: &[&str],
+    served_content_kinds: &[&str],
+) -> bool {
+    accepts_axis(query.filters.get("fileType"), served_file_types)
+        && accepts_axis(query.filters.get("contentKind"), served_content_kinds)
+}
+
+fn accepts_axis(requested: Option<&Vec<String>>, served: &[&str]) -> bool {
+    let Some(requested) = requested else {
+        return true;
+    };
+    if requested.is_empty() {
+        return true;
+    }
+    // Wildcard: a plugin that advertises `"*"` on an axis serves every value on
+    // that axis (e.g. tribler is a free-text overlay search with no inherent
+    // type limitation). It accepts any requested fileType/contentKind.
+    if served.contains(&"*") {
+        return true;
+    }
+    requested
+        .iter()
+        .any(|v| served.iter().any(|s| s.eq_ignore_ascii_case(v)))
+}
+
+/// Resolve a `languages` filter against the key-set storage form
+/// (`languages/<lang3> = "true"`). **Fails open** on anything we can't
+/// confidently exclude. A record matches when:
+/// 1. it carries a requested code as a truthy key-set member (OR across codes);
+/// 2. a legacy flat `languages` csv field contains a requested code;
+/// 3. it carries `mul` (multiple — may contain a requested one) or `und`
+///    (undetermined); or
+/// 4. it carries no language information at all.
+///
+/// Only a record with a *concrete*, non-matching language (e.g. `jpn`-only
+/// under an `eng` filter) is dropped. Kept byte-identical in logic with
+/// meta-search's copy (and the client's `passesLangFilter`) — language narrows
+/// the result set without ever hiding unknown/undetermined/multi releases.
+fn languages_filter_matches(fields: &BTreeMap<String, String>, allowed: &[String]) -> bool {
+    for code in allowed {
+        let key = format!("languages/{}", code.trim().to_ascii_lowercase());
+        if fields.get(&key).is_some_and(|v| is_truthy_member(v)) {
+            return true;
+        }
+    }
+    if let Some(flat) = fields.get("languages") {
+        if any_csv_value_matches(flat, allowed) {
+            return true;
+        }
+    }
+    // Fail open: `mul`/`und` are explicit "could be anything / unknown" markers,
+    // and a record with no concrete language at all is equally unknown. Keep all
+    // three; only a specific, non-matching language reaches the `false` below.
+    if fields.get("languages/mul").is_some_and(|v| is_truthy_member(v))
+        || fields.get("languages/und").is_some_and(|v| is_truthy_member(v))
+    {
+        return true;
+    }
+    !record_has_concrete_language(fields)
+}
+
+/// True iff the record states a *concrete* language: a truthy `languages/<code>`
+/// key-set member other than the `und`/`mul` non-codes, or a non-empty legacy
+/// flat `languages` field. Distinguishes "a specific language that didn't match
+/// ⇒ drop" from "no language info ⇒ keep" for [`languages_filter_matches`].
+fn record_has_concrete_language(fields: &BTreeMap<String, String>) -> bool {
+    if fields.get("languages").is_some_and(|v| !v.trim().is_empty()) {
+        return true;
+    }
+    fields.iter().any(|(k, v)| {
+        is_truthy_member(v)
+            && k.starts_with("languages/")
+            && k != "languages/und"
+            && k != "languages/mul"
+    })
+}
+
+/// Key-set members are written as the literal `"true"`; tolerate a couple of
+/// obvious truthy spellings and treat anything else as absent.
+/// Fold a genre label to its comparison form: lowercase, alphanumerics only.
+///
+/// Genre display names carry spaces and ampersands (`"Action & Adventure"`,
+/// `"Sci-Fi & Fantasy"`, `"Science Fiction"`), and **space is the query DSL's
+/// token separator** — so a filter can never spell a genre the way the record
+/// stores it. Callers pass a slug (`genres:action-adventure`); folding both
+/// sides makes them one value without forcing the stored name to be
+/// machine-shaped.
+fn genre_fold(s: &str) -> String {
+    s.chars()
+        .filter(|c| c.is_alphanumeric())
+        .flat_map(|c| c.to_lowercase())
+        .collect()
+}
+
+/// True iff the record carries one of the requested genres, in **either**
+/// encoding: a truthy `genres/<Name>` key-set member (the card tier's shape) or
+/// the legacy flat comma-joined `genres` field. OR across the requested genres,
+/// both sides folded — see [`genre_fold`].
+///
+/// **Fails closed, unlike [`languages_filter_matches`].** A language filter is a
+/// viewer *preference* narrowing a set, so an unknown-language release is kept.
+/// A genre filter *defines what a row is*: a record with no genre information is
+/// not known to be Action, so putting it in an Action row states something
+/// untrue. Upstream has already filtered by genre, so this is a re-validation.
+fn genres_filter_matches(fields: &BTreeMap<String, String>, allowed: &[String]) -> bool {
+    let wanted: Vec<String> = allowed.iter().map(|g| genre_fold(g)).collect();
+    if wanted.iter().all(|g| g.is_empty()) {
+        return true; // a filter with no usable value constrains nothing
+    }
+    for (key, value) in fields {
+        let Some(name) = key.strip_prefix("genres/") else {
+            continue;
+        };
+        if is_truthy_member(value) && wanted.contains(&genre_fold(name)) {
+            return true;
+        }
+    }
+    if let Some(flat) = fields.get("genres") {
+        for member in flat.split(|c| c == ',' || c == '|') {
+            if wanted.contains(&genre_fold(member)) {
+                return true;
+            }
+        }
+    }
+    false
+}
+
+fn is_truthy_member(v: &str) -> bool {
+    matches!(v.trim().to_ascii_lowercase().as_str(), "true" | "1" | "yes")
+}
+
+/// True iff `field_value` (treated as a csv set when it contains commas)
+/// contains at least one case-insensitive match for any item in `allowed`.
+fn any_csv_value_matches(field_value: &str, allowed: &[String]) -> bool {
+    for piece in field_value.split(',') {
+        let piece = piece.trim();
+        if piece.is_empty() {
+            continue;
+        }
+        if allowed.iter().any(|v| v.eq_ignore_ascii_case(piece)) {
+            return true;
+        }
+    }
+    false
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::query::{Negation, RangeFilter};
+
+    fn empty_query() -> GatewayQuery {
+        GatewayQuery {
+            raw_text: String::new(),
+            free_text: String::new(),
+            filters: BTreeMap::new(),
+            ranges: Vec::new(),
+            negations: Vec::new(),
+        }
+    }
+
+    fn with_filter(field: &str, values: &[&str]) -> GatewayQuery {
+        let mut q = empty_query();
+        q.filters.insert(
+            field.to_string(),
+            values.iter().map(|s| s.to_string()).collect(),
+        );
+        q
+    }
+
+    fn fields(pairs: &[(&str, &str)]) -> BTreeMap<String, String> {
+        pairs
+            .iter()
+            .map(|(k, v)| (k.to_string(), v.to_string()))
+            .collect()
+    }
+
+    #[test]
+    fn filter_rejects_mismatched_filetype() {
+        let q = with_filter("fileType", &["video"]);
+        assert!(!record_matches(&fields(&[("fileType", "image")]), &q));
+    }
+
+    #[test]
+    fn filter_accepts_matching_filetype() {
+        let q = with_filter("fileType", &["video"]);
+        assert!(record_matches(&fields(&[("fileType", "video")]), &q));
+    }
+
+    #[test]
+    fn filter_rejects_record_missing_field() {
+        let q = with_filter("fileType", &["video"]);
+        assert!(!record_matches(&fields(&[]), &q));
+    }
+
+    #[test]
+    fn filter_is_case_insensitive() {
+        let q = with_filter("fileType", &["VIDEO"]);
+        assert!(record_matches(&fields(&[("fileType", "video")]), &q));
+        let q = with_filter("fileType", &["video"]);
+        assert!(record_matches(&fields(&[("fileType", "VIDEO")]), &q));
+    }
+
+    #[test]
+    fn filter_ors_within_key() {
+        let q = with_filter("fileType", &["video", "audio"]);
+        assert!(record_matches(&fields(&[("fileType", "audio")]), &q));
+        assert!(record_matches(&fields(&[("fileType", "video")]), &q));
+        assert!(!record_matches(&fields(&[("fileType", "image")]), &q));
+    }
+
+    #[test]
+    fn filter_ands_across_keys() {
+        let mut q = with_filter("fileType", &["video"]);
+        q.filters.insert("genres".into(), vec!["Action".into()]);
+        assert!(!record_matches(
+            &fields(&[("fileType", "video"), ("genres", "Drama")]),
+            &q
+        ));
+        assert!(record_matches(
+            &fields(&[("fileType", "video"), ("genres", "Action")]),
+            &q
+        ));
+    }
+
+    #[test]
+    fn csv_field_matches_one_of_its_values() {
+        let q = with_filter("genres", &["Anime"]);
+        assert!(record_matches(
+            &fields(&[("genres", "Animation,Anime,Drama")]),
+            &q
+        ));
+    }
+
+    #[test]
+    fn csv_field_with_whitespace_is_trimmed() {
+        let q = with_filter("genres", &["Anime"]);
+        assert!(record_matches(
+            &fields(&[("genres", "Animation, Anime , Drama")]),
+            &q
+        ));
+    }
+
+    #[test]
+    fn languages_keyset_member_matches() {
+        let q = with_filter("languages", &["eng"]);
+        assert!(record_matches(&fields(&[("languages/eng", "true")]), &q));
+    }
+
+    #[test]
+    fn languages_filter_is_or_across_codes() {
+        let q = with_filter("languages", &["eng", "fre"]);
+        assert!(record_matches(&fields(&[("languages/eng", "true")]), &q));
+        assert!(record_matches(&fields(&[("languages/fre", "true")]), &q));
+        assert!(!record_matches(&fields(&[("languages/jpn", "true")]), &q));
+    }
+
+    #[test]
+    fn languages_filter_fails_open_on_unknown() {
+        let q = with_filter("languages", &["eng"]);
+        // No language info at all ⇒ kept (unknown, not excluded).
+        assert!(record_matches(&fields(&[("fileType", "video")]), &q));
+        // `mul` (multi) may contain the requested language ⇒ kept.
+        assert!(record_matches(&fields(&[("languages/mul", "true")]), &q));
+        // `und` (undetermined) ⇒ kept.
+        assert!(record_matches(&fields(&[("languages/und", "true")]), &q));
+        // A specific language alongside `mul` is still kept (multi).
+        assert!(record_matches(
+            &fields(&[("languages/jpn", "true"), ("languages/mul", "true")]),
+            &q
+        ));
+    }
+
+    #[test]
+    fn languages_concrete_mismatch_still_drops() {
+        let q = with_filter("languages", &["eng"]);
+        // A concrete, non-matching language ⇒ dropped (language narrows).
+        assert!(!record_matches(&fields(&[("languages/jpn", "true")]), &q));
+        // A tombstoned/false member is treated as absent ⇒ unknown ⇒ kept.
+        assert!(record_matches(&fields(&[("languages/eng", "false")]), &q));
+    }
+
+    #[test]
+    fn languages_legacy_flat_csv_fallback() {
+        let q = with_filter("languages", &["eng"]);
+        assert!(record_matches(&fields(&[("languages", "jpn,eng")]), &q));
+        assert!(!record_matches(&fields(&[("languages", "jpn,ger")]), &q));
+    }
+
+    #[test]
+    fn range_in_bounds() {
+        let mut q = empty_query();
+        q.ranges.push(RangeFilter {
+            field: "movieYear".into(),
+            lo: Some(2010),
+            hi: Some(2020),
+        });
+        assert!(record_matches(&fields(&[("movieYear", "2015")]), &q));
+    }
+
+    #[test]
+    fn range_out_of_bounds_rejected() {
+        let mut q = empty_query();
+        q.ranges.push(RangeFilter {
+            field: "movieYear".into(),
+            lo: Some(2010),
+            hi: Some(2020),
+        });
+        assert!(!record_matches(&fields(&[("movieYear", "2025")]), &q));
+        assert!(!record_matches(&fields(&[("movieYear", "2005")]), &q));
+    }
+
+    #[test]
+    fn range_open_upper_bound() {
+        let mut q = empty_query();
+        q.ranges.push(RangeFilter {
+            field: "movieYear".into(),
+            lo: Some(2010),
+            hi: None,
+        });
+        assert!(record_matches(&fields(&[("movieYear", "2025")]), &q));
+    }
+
+    #[test]
+    fn range_unparseable_value_rejected() {
+        let mut q = empty_query();
+        q.ranges.push(RangeFilter {
+            field: "movieYear".into(),
+            lo: Some(2010),
+            hi: None,
+        });
+        assert!(!record_matches(&fields(&[("movieYear", "circa 2015")]), &q));
+    }
+
+    #[test]
+    fn typed_negation_excludes_match() {
+        let mut q = empty_query();
+        q.negations.push(Negation {
+            field: Some("fileType".into()),
+            value: "image".into(),
+        });
+        assert!(!record_matches(&fields(&[("fileType", "image")]), &q));
+        assert!(record_matches(&fields(&[("fileType", "video")]), &q));
+    }
+
+    #[test]
+    fn typed_negation_passes_when_field_missing() {
+        let mut q = empty_query();
+        q.negations.push(Negation {
+            field: Some("fileType".into()),
+            value: "image".into(),
+        });
+        assert!(record_matches(&fields(&[]), &q));
+    }
+
+    #[test]
+    fn bare_word_negation_is_not_enforced() {
+        let mut q = empty_query();
+        q.negations.push(Negation {
+            field: None,
+            value: "alice".into(),
+        });
+        assert!(record_matches(
+            &fields(&[("title", "alice in wonderland")]),
+            &q
+        ));
+    }
+
+    #[test]
+    fn empty_query_matches_anything() {
+        assert!(record_matches(&fields(&[]), &empty_query()));
+        assert!(record_matches(
+            &fields(&[("fileType", "video"), ("title", "x")]),
+            &empty_query()
+        ));
+    }
+
+    #[test]
+    fn accepts_returns_true_when_no_type_filter() {
+        let q = empty_query();
+        assert!(query_accepts_plugin(&q, &["video"], &["movie"]));
+        assert!(query_accepts_plugin(&q, &[], &[]));
+    }
+
+    #[test]
+    fn accepts_rejects_disjoint_filetype() {
+        let q = with_filter("fileType", &["video"]);
+        assert!(!query_accepts_plugin(&q, &["image"], &["gif"]));
+        assert!(query_accepts_plugin(&q, &["video"], &[]));
+    }
+
+    #[test]
+    fn accepts_rejects_disjoint_contentkind() {
+        let q = with_filter("contentKind", &["movie"]);
+        assert!(!query_accepts_plugin(
+            &q,
+            &["video", "image"],
+            &["paper", "book"]
+        ));
+        assert!(query_accepts_plugin(&q, &["video"], &["movie", "episode"]));
+    }
+
+    #[test]
+    fn accepts_requires_both_axes_when_both_filtered() {
+        let mut q = with_filter("fileType", &["video"]);
+        q.filters.insert("contentKind".into(), vec!["movie".into()]);
+        assert!(query_accepts_plugin(&q, &["video"], &["movie"]));
+        assert!(!query_accepts_plugin(&q, &["video"], &["paper"]));
+        assert!(!query_accepts_plugin(&q, &["image"], &["movie"]));
+    }
+
+    #[test]
+    fn accepts_wildcard_matches_any_requested_type() {
+        // A plugin advertising "*" (e.g. tribler) accepts any fileType /
+        // contentKind filter on the wildcarded axis.
+        let q = with_filter("fileType", &["archive"]);
+        assert!(query_accepts_plugin(&q, &["*"], &[]));
+        let q = with_filter("contentKind", &["audiobook"]);
+        assert!(query_accepts_plugin(&q, &["*"], &["*"]));
+        // Wildcard on one axis only: the non-wildcard axis still gates.
+        let mut q = with_filter("fileType", &["audio"]);
+        q.filters.insert("contentKind".into(), vec!["podcast".into()]);
+        assert!(query_accepts_plugin(&q, &["*"], &["*"]));
+        assert!(!query_accepts_plugin(&q, &["*"], &["movie"]));
+    }
+}

src/serve.rs

@@ -0,0 +1,762 @@
+//! `serve_feeders` — the axum harness that exposes a set of [`FeederPlugin`]s
+//! over the **feeder HTTP contract**. Every feeder sidecar binary is just
+//! `serve_feeders(vec![MyPlugin::new()], state_dir, listen)`.
+//!
+//! # Contract (JSON over HTTP, mirrors meta-sort's container-plugin shape)
+//!
+//! - `GET  /manifest`                  → [`ManifestResponse`]
+//! - `GET  /health`                    → [`HealthResponse`]
+//! - `POST /query`                     → [`QueryRequest`] → [`QueryResponse`]
+//! - `POST /compute`                   → [`ComputeRequest`] → [`ComputeResponse`]
+//! - `GET  /fetch/{upstream_id}/{record_id}` → streamed bytes (or 404)
+//! - `GET  /blob/{upstream_id}/{cid}`  → bytes (or 404)
+//!
+//! ## Bytes & the v1 simplification
+//!
+//! `/compute` returns each outcome's bytes **inline, base64-encoded**
+//! ([`OutcomeDto::bytes_b64`]) — this reuses every existing `compute_outcomes`
+//! impl verbatim (they already return bytes in `HashOutcome.bytes`) and keeps
+//! the gateway core's auto-store a single round-trip. base64 adds ~33%; fine
+//! for books/papers/posters. Large-file streaming (torznab multi-GiB) is a
+//! documented follow-up — those outcomes are metadata-only anyway
+//! (`bytes: None`), so they never ride this path.
+
+use std::collections::HashMap;
+use std::net::SocketAddr;
+use std::path::{Path as FsPath, PathBuf};
+use std::sync::Arc;
+
+use axum::{
+    body::Body,
+    extract::{Path, State},
+    http::StatusCode,
+    response::{Html, IntoResponse, Response},
+    routing::{get, post},
+    Json, Router,
+};
+use base64::Engine as _;
+use futures::StreamExt;
+use serde::{Deserialize, Serialize};
+use serde_json::Value;
+use tracing::{info, warn};
+
+use crate::config::{self, CONFIG_PAGE_HTML};
+use crate::plugin::{ConfigError, FeederPlugin, HashKind, HashOutcome};
+use crate::query::{GatewayQuery, GatewaySearchEvent, GatewayWireError};
+use crate::types::{DiscoveryRecord, GatewayError, PluginHealth};
+
+// -------- wire DTOs --------------------------------------------------------
+
+/// Serializable mirror of [`HashKind`] for the feeder HTTP boundary.
+#[derive(Serialize, Deserialize, Clone, Copy, PartialEq, Eq, Debug)]
+#[serde(rename_all = "snake_case")]
+pub enum HashKindDto {
+    Midhash256,
+    Sha2_256,
+    BtV1File,
+    NzbRelease,
+    CardLocator,
+    NzbPosting,
+    YtVideo,
+}
+
+impl From<HashKind> for HashKindDto {
+    fn from(k: HashKind) -> Self {
+        match k {
+            HashKind::Midhash256 => HashKindDto::Midhash256,
+            HashKind::Sha2_256 => HashKindDto::Sha2_256,
+            HashKind::BtV1File => HashKindDto::BtV1File,
+            HashKind::NzbRelease => HashKindDto::NzbRelease,
+            HashKind::CardLocator => HashKindDto::CardLocator,
+            HashKind::NzbPosting => HashKindDto::NzbPosting,
+            HashKind::YtVideo => HashKindDto::YtVideo,
+        }
+    }
+}
+
+impl From<HashKindDto> for HashKind {
+    fn from(k: HashKindDto) -> Self {
+        match k {
+            HashKindDto::Midhash256 => HashKind::Midhash256,
+            HashKindDto::Sha2_256 => HashKind::Sha2_256,
+            HashKindDto::BtV1File => HashKind::BtV1File,
+            HashKindDto::NzbRelease => HashKind::NzbRelease,
+            HashKindDto::CardLocator => HashKind::CardLocator,
+            HashKindDto::NzbPosting => HashKind::NzbPosting,
+            HashKindDto::YtVideo => HashKind::YtVideo,
+        }
+    }
+}
+
+/// One plugin's capability surface in [`ManifestResponse`].
+#[derive(Serialize, Deserialize, Clone, Debug)]
+pub struct PluginManifest {
+    pub id: String,
+    pub served_file_types: Vec<String>,
+    pub served_content_kinds: Vec<String>,
+}
+
+/// `GET /manifest` — the feeder's hosted plugins + their served types. The
+/// gateway core reads this to register `RemoteFeederPlugin`s and to build the
+/// capability heartbeat it broadcasts to meta-share.
+#[derive(Serialize, Deserialize, Clone, Debug)]
+pub struct ManifestResponse {
+    pub feeder_version: String,
+    pub plugins: Vec<PluginManifest>,
+}
+
+/// One plugin's liveness in [`HealthResponse`].
+#[derive(Serialize, Deserialize, Clone, Debug)]
+pub struct PluginHealthEntry {
+    pub id: String,
+    pub health: PluginHealth,
+}
+
+/// `GET /health` — `status` is `"ok"` iff every hosted plugin reports `Ok`.
+#[derive(Serialize, Deserialize, Clone, Debug)]
+pub struct HealthResponse {
+    pub status: String,
+    pub plugins: Vec<PluginHealthEntry>,
+}
+
+/// `POST /query` request body.
+#[derive(Serialize, Deserialize, Clone, Debug)]
+pub struct QueryRequest {
+    pub upstream_id: String,
+    pub query: GatewayQuery,
+    pub max_results: u32,
+}
+
+/// `POST /query` response body.
+#[derive(Serialize, Deserialize, Clone, Debug)]
+pub struct QueryResponse {
+    pub records: Vec<DiscoveryRecord>,
+}
+
+/// `POST /compute` request body.
+#[derive(Serialize, Deserialize, Clone, Debug)]
+pub struct ComputeRequest {
+    pub upstream_id: String,
+    pub record_id: String,
+}
+
+/// One resolved outcome on the feeder wire. `bytes_b64` carries the full
+/// payload base64-encoded when the plugin fetched bytes (`Sha2_256` full
+/// store); `None` for metadata-only outcomes (the core's `(None, Some)`
+/// branch — e.g. torznab midhash).
+#[derive(Serialize, Deserialize, Clone, Debug)]
+pub struct OutcomeDto {
+    pub hash: String,
+    pub hash_kind: HashKindDto,
+    pub file_extension: Option<String>,
+    pub record: Option<DiscoveryRecord>,
+    pub bytes_b64: Option<String>,
+}
+
+impl OutcomeDto {
+    fn from_outcome(o: HashOutcome) -> Self {
+        OutcomeDto {
+            hash: o.hash.0,
+            hash_kind: o.hash_kind.into(),
+            file_extension: o.file_extension,
+            record: o.record,
+            bytes_b64: o
+                .bytes
+                .map(|b| base64::engine::general_purpose::STANDARD.encode(&b)),
+        }
+    }
+}
+
+/// `POST /compute` response body.
+#[derive(Serialize, Deserialize, Clone, Debug)]
+pub struct ComputeResponse {
+    pub outcomes: Vec<OutcomeDto>,
+}
+
+// -------- app state + error mapping ----------------------------------------
+
+#[derive(Clone)]
+struct AppState {
+    plugins: Arc<HashMap<String, Arc<dyn FeederPlugin>>>,
+    version: String,
+    /// Feeder state dir. Per-plugin config persists at
+    /// `state_dir/gateway/<id>/config.json` — the same per-plugin dir handed to
+    /// `configure()`, so a UI save is read back on the next restart.
+    state_dir: PathBuf,
+}
+
+impl AppState {
+    fn plugin(&self, upstream_id: &str) -> Result<&Arc<dyn FeederPlugin>, Response> {
+        self.plugins.get(upstream_id).ok_or_else(|| {
+            (
+                StatusCode::NOT_FOUND,
+                format!("no feeder plugin for upstream_id '{upstream_id}'"),
+            )
+                .into_response()
+        })
+    }
+
+    /// `state_dir/gateway/<id>/config.json` — canonical per-plugin config file.
+    fn config_path(&self, upstream_id: &str) -> PathBuf {
+        self.state_dir
+            .join("gateway")
+            .join(upstream_id)
+            .join("config.json")
+    }
+
+    /// The effective config as JSON: the persisted `config.json` if it exists,
+    /// else the plugin's in-memory (env-seeded) config. Used as the redaction
+    /// source for reads and the merge base for writes.
+    fn effective_config(&self, upstream_id: &str) -> Value {
+        if let Ok(bytes) = std::fs::read(self.config_path(upstream_id)) {
+            if let Ok(v) = serde_json::from_slice::<Value>(&bytes) {
+                return v;
+            }
+        }
+        self.plugins
+            .get(upstream_id)
+            .map(|p| p.config_values())
+            .unwrap_or_else(|| serde_json::json!({}))
+    }
+}
+
+/// Map an in-process [`GatewayError`] to an HTTP status + message. Mirrors the
+/// status semantics the gateway's `RemoteFeederPlugin` will translate back
+/// into a `GatewayError` on the core side.
+fn gateway_error_response(e: GatewayError) -> Response {
+    let (status, msg) = match e {
+        GatewayError::NotFound => (StatusCode::NOT_FOUND, "not found".to_string()),
+        GatewayError::RateLimited { retry_after_s } => (
+            StatusCode::TOO_MANY_REQUESTS,
+            format!("rate limited; retry in {retry_after_s}s"),
+        ),
+        GatewayError::Transient(s) => (StatusCode::BAD_GATEWAY, s),
+        GatewayError::Permanent(s) => (StatusCode::UNPROCESSABLE_ENTITY, s),
+        GatewayError::Internal(s) => (StatusCode::INTERNAL_SERVER_ERROR, s.to_string()),
+    };
+    (status, msg).into_response()
+}
+
+// -------- handlers ---------------------------------------------------------
+
+async fn manifest(State(state): State<AppState>) -> Json<ManifestResponse> {
+    let mut plugins: Vec<PluginManifest> = state
+        .plugins
+        .values()
+        .map(|p| PluginManifest {
+            id: p.upstream_id().to_string(),
+            served_file_types: p.served_file_types().iter().map(|s| s.to_string()).collect(),
+            served_content_kinds: p
+                .served_content_kinds()
+                .iter()
+                .map(|s| s.to_string())
+                .collect(),
+        })
+        .collect();
+    plugins.sort_by(|a, b| a.id.cmp(&b.id));
+    Json(ManifestResponse {
+        feeder_version: state.version.clone(),
+        plugins,
+    })
+}
+
+async fn health(State(state): State<AppState>) -> Json<HealthResponse> {
+    let mut entries: Vec<PluginHealthEntry> = state
+        .plugins
+        .values()
+        .map(|p| PluginHealthEntry {
+            id: p.upstream_id().to_string(),
+            health: p.health(),
+        })
+        .collect();
+    entries.sort_by(|a, b| a.id.cmp(&b.id));
+    let all_ok = entries
+        .iter()
+        .all(|e| matches!(e.health, PluginHealth::Ok));
+    Json(HealthResponse {
+        status: if all_ok { "ok" } else { "degraded" }.to_string(),
+        plugins: entries,
+    })
+}
+
+async fn query(
+    State(state): State<AppState>,
+    Json(req): Json<QueryRequest>,
+) -> Result<Json<QueryResponse>, Response> {
+    let plugin = state.plugin(&req.upstream_id)?;
+    let records = plugin
+        .handle_query(&req.query, req.max_results as usize)
+        .await
+        .map_err(gateway_error_response)?;
+    Ok(Json(QueryResponse { records }))
+}
+
+/// `POST /query_stream` — the streaming analog of [`query`]. Emits the plugin's
+/// [`FeederPlugin::handle_query_stream`] events as **NDJSON**: one JSON-encoded
+/// [`GatewaySearchEvent`] per line (`application/x-ndjson`). The gateway core's
+/// `RemoteFeederPlugin` consumes this and re-emits a `BoxStream<GatewaySearchEvent>`
+/// into the libp2p streaming worker, preserving incremental enrichment (e.g.
+/// torznab's late TMDB / poster / subtitle-availability patches). A plugin that
+/// doesn't override `handle_query_stream` still works here — the trait default
+/// replays `handle_query` as `Base* + Done`.
+async fn query_stream(
+    State(state): State<AppState>,
+    Json(req): Json<QueryRequest>,
+) -> Result<Response, Response> {
+    let plugin = state.plugin(&req.upstream_id)?;
+    // The open can fail (e.g. the plugin can't reach its upstream at all); that
+    // maps to an HTTP error status, same as `/query`. Per-event errors instead
+    // ride the stream as a terminal `GatewaySearchEvent::Error` line.
+    let events = plugin
+        .handle_query_stream(&req.query, req.max_results as usize)
+        .await
+        .map_err(gateway_error_response)?;
+    let body = events.map(|ev| {
+        // Serialization of GatewaySearchEvent is infallible in practice; on the
+        // off chance it fails, terminate with an Error line so the consumer sees
+        // a clean terminal failure rather than a truncated stream.
+        let mut line = serde_json::to_vec(&ev).unwrap_or_else(|e| {
+            serde_json::to_vec(&GatewaySearchEvent::Error(GatewayWireError::Internal(
+                format!("event serialize: {e}"),
+            )))
+            .unwrap_or_default()
+        });
+        line.push(b'\n');
+        Ok::<_, std::convert::Infallible>(line)
+    });
+    Ok((
+        [(axum::http::header::CONTENT_TYPE, "application/x-ndjson")],
+        Body::from_stream(body),
+    )
+        .into_response())
+}
+
+async fn compute(
+    State(state): State<AppState>,
+    Json(req): Json<ComputeRequest>,
+) -> Result<Json<ComputeResponse>, Response> {
+    let plugin = state.plugin(&req.upstream_id)?;
+    let outcomes = plugin
+        .compute_outcomes(&req.record_id)
+        .await
+        .map_err(gateway_error_response)?;
+    Ok(Json(ComputeResponse {
+        outcomes: outcomes.into_iter().map(OutcomeDto::from_outcome).collect(),
+    }))
+}
+
+async fn fetch(
+    State(state): State<AppState>,
+    Path((upstream_id, record_id)): Path<(String, String)>,
+) -> Result<Response, Response> {
+    let plugin = state.plugin(&upstream_id)?;
+    match plugin
+        .handle_fetch(&record_id)
+        .await
+        .map_err(gateway_error_response)?
+    {
+        Some(stream) => {
+            // Map the plugin's GatewayError stream into an io::Error stream so
+            // axum's Body::from_stream accepts it.
+            let body_stream = stream.map(|chunk| {
+                chunk.map_err(|e| std::io::Error::other(e.to_string()))
+            });
+            Ok(Body::from_stream(body_stream).into_response())
+        }
+        None => Err((StatusCode::NOT_FOUND, "no bytes for record").into_response()),
+    }
+}
+
+async fn blob(
+    State(state): State<AppState>,
+    Path((upstream_id, cid)): Path<(String, String)>,
+) -> Result<Response, Response> {
+    let plugin = state.plugin(&upstream_id)?;
+    match plugin.get_blob(&cid).await {
+        Some(bytes) => Ok(bytes.into_response()),
+        None => Err((StatusCode::NOT_FOUND, "no such blob").into_response()),
+    }
+}
+
+// -------- config plane -----------------------------------------------------
+//
+// Generic, schema-driven per-plugin config. The page + the schema/values JSON
+// are all served relative to the request path, so this works identically when
+// hit directly on the feeder or reverse-proxied through the gateway.
+
+/// `GET /config` — the schema-driven HTML form (static, plugin-agnostic).
+async fn config_page() -> Html<&'static str> {
+    Html(CONFIG_PAGE_HTML)
+}
+
+/// `GET /config/schema` — the single hosted plugin's declared config schema.
+/// (A feeder hosts one plugin in practice; if it hosts several, the first by
+/// id is used — the gateway proxies per upstream_id anyway.)
+async fn config_schema(State(state): State<AppState>) -> Json<config::ConfigSchema> {
+    let schema = sole_plugin(&state)
+        .map(|p| p.config_schema())
+        .unwrap_or_default();
+    Json(schema)
+}
+
+/// `GET /config/values` — current values with secrets redacted to `<key>_set`.
+async fn config_values_get(State(state): State<AppState>) -> Json<Value> {
+    match sole_plugin(&state) {
+        Some(p) => {
+            let schema = p.config_schema();
+            let eff = state.effective_config(p.upstream_id());
+            Json(config::redact(&eff, &schema))
+        }
+        None => Json(serde_json::json!({})),
+    }
+}
+
+/// `PUT /config/values` — merge the submitted values onto the stored config
+/// (schema-aware; blank secrets keep their stored value), persist atomically,
+/// and signal that a feeder restart is needed to apply them.
+async fn config_values_put(
+    State(state): State<AppState>,
+    Json(incoming): Json<Value>,
+) -> Result<Json<Value>, Response> {
+    let plugin = sole_plugin(&state)
+        .ok_or_else(|| (StatusCode::NOT_FOUND, "feeder hosts no plugin").into_response())?;
+    let id = plugin.upstream_id();
+    let schema = plugin.config_schema();
+    let base = state.effective_config(id);
+    let merged = config::merge(&base, &incoming, &schema);
+
+    let path = state.config_path(id);
+    if let Some(dir) = path.parent() {
+        std::fs::create_dir_all(dir)
+            .map_err(|e| (StatusCode::INTERNAL_SERVER_ERROR, format!("mkdir: {e}")).into_response())?;
+    }
+    let tmp = path.with_extension("json.tmp");
+    let body = serde_json::to_vec_pretty(&merged)
+        .map_err(|e| (StatusCode::INTERNAL_SERVER_ERROR, format!("serialize: {e}")).into_response())?;
+    std::fs::write(&tmp, body)
+        .and_then(|_| std::fs::rename(&tmp, &path))
+        .map_err(|e| (StatusCode::INTERNAL_SERVER_ERROR, format!("write config: {e}")).into_response())?;
+    info!(target: "meta-feeder", upstream_id = id, path = %path.display(), "feeder config saved; scheduling self-restart to apply");
+    // Apply the new config by restarting the process. We can't hot-swap config
+    // in-place: plugins hold an exclusive redb cache handle for their whole life,
+    // so a fresh instance can't reopen the cache while the old one is alive. A
+    // clean process exit is the reliable apply path — Docker's restart policy
+    // (`unless-stopped`) brings the feeder back in ~2-3s and `configure()`
+    // re-reads config.json at startup. Delay briefly so THIS response flushes to
+    // the client before we exit.
+    tokio::spawn(async {
+        tokio::time::sleep(std::time::Duration::from_millis(800)).await;
+        info!(target: "meta-feeder", "restarting now to apply saved config");
+        std::process::exit(0);
+    });
+    Ok(Json(serde_json::json!({ "saved": true, "reloading": true })))
+}
+
+/// `POST /enrich/callback` — sink for the enrichment plugins' completion
+/// callbacks. The feeder drives those plugins (filename-parser, tmdb) during a
+/// self-published resolve and reads results back by polling meta-core, so the
+/// callback carries no load — this route exists only so the plugins' callback
+/// POST gets a 200 instead of logging a connection failure. Body is ignored.
+async fn enrich_callback() -> StatusCode {
+    StatusCode::OK
+}
+
+/// A feeder hosts one plugin in the common case. Pick it (lowest id for
+/// determinism if several are present).
+fn sole_plugin(state: &AppState) -> Option<&Arc<dyn FeederPlugin>> {
+    state
+        .plugins
+        .values()
+        .min_by(|a, b| a.upstream_id().cmp(b.upstream_id()))
+}
+
+// -------- entry point ------------------------------------------------------
+
+/// Build the feeder router for an already-configured plugin set. Exposed for
+/// in-process tests (drive it without binding a socket).
+pub fn router(
+    plugins: HashMap<String, Arc<dyn FeederPlugin>>,
+    version: String,
+    state_dir: impl Into<PathBuf>,
+) -> Router {
+    let state = AppState {
+        plugins: Arc::new(plugins),
+        version,
+        state_dir: state_dir.into(),
+    };
+    Router::new()
+        .route("/manifest", get(manifest))
+        .route("/health", get(health))
+        .route("/query", post(query))
+        .route("/query_stream", post(query_stream))
+        .route("/compute", post(compute))
+        .route("/fetch/:upstream_id/:record_id", get(fetch))
+        .route("/blob/:upstream_id/:cid", get(blob))
+        .route("/config", get(config_page))
+        .route("/config/schema", get(config_schema))
+        .route("/config/values", get(config_values_get).put(config_values_put))
+        .route("/enrich/callback", post(enrich_callback))
+        .with_state(state)
+}
+
+/// Configure each plugin (cache dir under `state_dir/gateway/<id>`), then serve
+/// the feeder HTTP contract on `listen` until shutdown.
+///
+/// The feeder process never aborts on a config problem: a plugin whose
+/// `configure()` returns [`ConfigError::MissingConfig`] is **soft-skipped**
+/// (warn + dropped — an optional source the operator didn't ask for), and any
+/// other failure (bad/empty key, cache-dir setup, …) registers a
+/// [`DegradedPlugin`] that stays up and reports the reason via `/health` and
+/// `/manifest`. The container keeps running so the error is visible in the UX
+/// instead of crash-looping.
+pub async fn serve_feeders(
+    plugins: Vec<Box<dyn FeederPlugin>>,
+    state_dir: impl Into<PathBuf>,
+    listen: SocketAddr,
+) -> anyhow::Result<()> {
+    let state_dir = state_dir.into();
+    let configured = configure_plugins(plugins, &state_dir)?;
+    let version = env!("CARGO_PKG_VERSION").to_string();
+    let app = router(configured, version, state_dir.clone());
+
+    let listener = tokio::net::TcpListener::bind(listen).await?;
+    info!(
+        target: "meta-feeder",
+        %listen,
+        "feeder listening"
+    );
+    axum::serve(listener, app)
+        .await
+        .map_err(anyhow::Error::from)
+}
+
+/// A plugin whose `configure()` (or cache-dir setup) failed. It stays
+/// **registered** so the failure is visible at `GET /health` (as
+/// [`PluginHealth::Degraded`]) and `GET /manifest`; any query/compute against it
+/// returns the captured reason as a permanent error. This is what keeps one
+/// misconfigured feeder from crash-looping the whole container — the operator
+/// sees the reason in the UX and fixes the config, no restart-loop required.
+struct DegradedPlugin {
+    id: &'static str,
+    reason: String,
+    file_types: &'static [&'static str],
+    content_kinds: &'static [&'static str],
+    /// Preserved from the wrapped plugin so a degraded/unconfigured feeder still
+    /// serves its config form — otherwise the dashboard shows "no configuration
+    /// required" and the operator can never fix the very config that's missing.
+    schema: crate::config::ConfigSchema,
+}
+
+#[async_trait::async_trait]
+impl FeederPlugin for DegradedPlugin {
+    fn upstream_id(&self) -> &'static str {
+        self.id
+    }
+
+    fn configure(&mut self, _cache_dir: &FsPath) -> Result<(), ConfigError> {
+        Ok(())
+    }
+
+    async fn handle_query(
+        &self,
+        _query: &GatewayQuery,
+        _max_results: usize,
+    ) -> Result<Vec<DiscoveryRecord>, GatewayError> {
+        Err(GatewayError::Permanent(self.reason.clone()))
+    }
+
+    async fn compute_outcomes(
+        &self,
+        _record_id: &str,
+    ) -> Result<Vec<HashOutcome>, GatewayError> {
+        Err(GatewayError::Permanent(self.reason.clone()))
+    }
+
+    fn health(&self) -> PluginHealth {
+        PluginHealth::Degraded {
+            reason: self.reason.clone(),
+        }
+    }
+
+    fn served_file_types(&self) -> &'static [&'static str] {
+        self.file_types
+    }
+
+    fn served_content_kinds(&self) -> &'static [&'static str] {
+        self.content_kinds
+    }
+
+    fn config_schema(&self) -> crate::config::ConfigSchema {
+        self.schema.clone()
+    }
+}
+
+/// Run each plugin's `configure()` against its per-plugin cache dir and return
+/// the plugins keyed by `upstream_id`. Never errors on a per-plugin problem:
+/// `MissingConfig` is soft-skipped, every other failure becomes a
+/// [`DegradedPlugin`] (see [`serve_feeders`]). Public so feeder binaries /
+/// tests can configure without serving.
+pub fn configure_plugins(
+    plugins: Vec<Box<dyn FeederPlugin>>,
+    state_dir: &FsPath,
+) -> anyhow::Result<HashMap<String, Arc<dyn FeederPlugin>>> {
+    let mut out: HashMap<String, Arc<dyn FeederPlugin>> = HashMap::new();
+    for mut plugin in plugins {
+        let id = plugin.upstream_id();
+        // Captured up front (both are `'static`, so this borrow of `plugin`
+        // ends immediately) — lets us build a DegradedPlugin without holding a
+        // borrow across `configure(&mut self)` / the move into `out`.
+        let file_types = plugin.served_file_types();
+        let content_kinds = plugin.served_content_kinds();
+        // Preserve the config surface so a degraded stand-in still serves the
+        // real config form (see DegradedPlugin.schema).
+        let schema = plugin.config_schema();
+        let cache_dir = state_dir.join("gateway").join(id);
+
+        // Build (don't insert) a degraded stand-in: keeps the container up and
+        // surfaces the reason via /health instead of crash-looping.
+        let make_degraded = |reason: String| -> Arc<dyn FeederPlugin> {
+            warn!(
+                target: "meta-feeder",
+                upstream_id = id,
+                %reason,
+                "feeder plugin degraded: container stays up; error surfaced via /health"
+            );
+            Arc::new(DegradedPlugin {
+                id,
+                reason,
+                file_types,
+                content_kinds,
+                schema: schema.clone(),
+            })
+        };
+
+        if let Err(e) = std::fs::create_dir_all(&cache_dir) {
+            let reason = format!("cache dir {} setup failed: {e}", cache_dir.display());
+            out.insert(id.to_string(), make_degraded(reason));
+            continue;
+        }
+
+        match plugin.configure(&cache_dir) {
+            Ok(()) => {
+                out.insert(id.to_string(), Arc::from(plugin));
+            }
+            Err(ConfigError::MissingConfig { plugin: p, what }) => {
+                // Keep a degraded stand-in (don't drop it) so its config form
+                // stays reachable from the dashboard and the operator can supply
+                // the missing config — then restart the feeder to apply it.
+                warn!(
+                    target: "meta-feeder",
+                    upstream_id = %p,
+                    missing = %what,
+                    "feeder plugin degraded: required config not supplied; \
+                     config form still served so it can be fixed from the dashboard"
+                );
+                out.insert(
+                    id.to_string(),
+                    make_degraded(format!("required config not supplied: {what}")),
+                );
+            }
+            Err(other) => {
+                out.insert(id.to_string(), make_degraded(other.to_string()));
+            }
+        }
+    }
+    Ok(out)
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::types::DiscoveryRecord;
+    use async_trait::async_trait;
+    use futures::stream::BoxStream;
+    use std::collections::BTreeMap;
+
+    /// A feeder plugin that overrides `handle_query_stream` to emit a Base, then
+    /// an EnrichPatch, then Done — so the NDJSON route is exercised on a real
+    /// incremental stream (not just the collect-default).
+    struct StubStreaming;
+
+    #[async_trait]
+    impl FeederPlugin for StubStreaming {
+        fn upstream_id(&self) -> &'static str {
+            "stub"
+        }
+        fn configure(&mut self, _cache_dir: &FsPath) -> Result<(), ConfigError> {
+            Ok(())
+        }
+        async fn handle_query(
+            &self,
+            _q: &GatewayQuery,
+            _n: usize,
+        ) -> Result<Vec<DiscoveryRecord>, GatewayError> {
+            Ok(vec![])
+        }
+        async fn handle_query_stream(
+            &self,
+            _q: &GatewayQuery,
+            _n: usize,
+        ) -> Result<BoxStream<'static, GatewaySearchEvent>, GatewayError> {
+            let rec = DiscoveryRecord {
+                upstream_id: "stub".into(),
+                record_id: "1".into(),
+                fields: BTreeMap::new(),
+            };
+            let events = vec![
+                GatewaySearchEvent::Base(rec),
+                GatewaySearchEvent::EnrichPatch {
+                    record_id: "1".into(),
+                    set: BTreeMap::from([("title".to_string(), "X".to_string())]),
+                    remove: vec![],
+                },
+                GatewaySearchEvent::Done,
+            ];
+            Ok(Box::pin(futures::stream::iter(events)))
+        }
+        async fn compute_outcomes(
+            &self,
+            _record_id: &str,
+        ) -> Result<Vec<HashOutcome>, GatewayError> {
+            Ok(vec![])
+        }
+    }
+
+    #[tokio::test]
+    async fn query_stream_emits_ndjson_events_in_order() {
+        let mut plugins: HashMap<String, Arc<dyn FeederPlugin>> = HashMap::new();
+        plugins.insert("stub".to_string(), Arc::new(StubStreaming));
+        let app = router(plugins, "test".to_string(), std::env::temp_dir());
+
+        let listener = tokio::net::TcpListener::bind("127.0.0.1:0").await.unwrap();
+        let addr = listener.local_addr().unwrap();
+        tokio::spawn(async move {
+            axum::serve(listener, app).await.unwrap();
+        });
+
+        let body = reqwest::Client::new()
+            .post(format!("http://{addr}/query_stream"))
+            .json(&serde_json::json!({
+                "upstream_id": "stub",
+                "query": {"raw_text":"x","free_text":"x","filters":{},"ranges":[],"negations":[]},
+                "max_results": 5
+            }))
+            .send()
+            .await
+            .unwrap()
+            .text()
+            .await
+            .unwrap();
+
+        let events: Vec<GatewaySearchEvent> = body
+            .lines()
+            .filter(|l| !l.trim().is_empty())
+            .map(|l| serde_json::from_str(l).expect("each NDJSON line is a GatewaySearchEvent"))
+            .collect();
+
+        assert_eq!(events.len(), 3, "body was: {body:?}");
+        assert!(matches!(events[0], GatewaySearchEvent::Base(_)));
+        assert!(matches!(events[1], GatewaySearchEvent::EnrichPatch { .. }));
+        assert!(matches!(events[2], GatewaySearchEvent::Done));
+    }
+}

src/types.rs

@@ -0,0 +1,124 @@
+//! In-process types used by the gateway runtime, feeders, and plugins.
+//!
+//! `GatewayError` here is **distinct from** the wire-stable
+//! `GatewayWireError` (see [`crate::query`]): this one can carry rich
+//! internal context (anyhow chains, plugin specifics); the wire one is narrow
+//! on purpose since adding variants is a protocol change. Conversion happens
+//! at the protocol boundary.
+
+use std::collections::BTreeMap;
+
+use serde::{Deserialize, Serialize};
+
+/// Content-addressed hash string carried over the wire. Renamed from
+/// `Midhash` in the multi-outcome plugin contract migration — the name
+/// `Midhash` lied for sha2-256 CIDs (which gateway plugins also emit
+/// via `compute_ipfs_cid`). The carrier is generic; the hash family is
+/// discriminated by `HashKind` on `HashOutcome`.
+///
+/// Shape: base32-lower 'b'-prefixed multibase CIDv1. The specific
+/// multihash inside (`0x1000` for midhash256, `0x12` for sha2-256) is
+/// determined by the producing plugin's hashing path.
+#[derive(Clone, Debug, PartialEq, Eq, Hash, Serialize, Deserialize)]
+pub struct Hash(pub String);
+
+impl Hash {
+    pub fn as_str(&self) -> &str {
+        &self.0
+    }
+}
+
+impl std::fmt::Display for Hash {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        f.write_str(&self.0)
+    }
+}
+
+/// Pre-hash identifier for a record discovered through a gateway.
+#[derive(Clone, Debug, PartialEq, Eq, Hash, Serialize, Deserialize)]
+pub struct DiscoveryId {
+    pub upstream_id: String,
+    pub record_id: String,
+}
+
+/// Metadata-only search result. Distinct from meta-core's persistent record
+/// (which is a flat `map[string]string` indexed by midhash); a
+/// `DiscoveryRecord` only lives inside the gateway search/response pipeline.
+#[derive(Clone, Debug, PartialEq, Eq, Serialize, Deserialize)]
+pub struct DiscoveryRecord {
+    pub upstream_id: String,
+    pub record_id: String,
+    pub fields: BTreeMap<String, String>,
+}
+
+/// In-process error returned by `FeederPlugin` methods.
+#[derive(Debug, thiserror::Error)]
+pub enum GatewayError {
+    #[error("upstream transient error: {0}")]
+    Transient(String),
+
+    #[error("upstream permanent error: {0}")]
+    Permanent(String),
+
+    #[error("rate limited; retry in {retry_after_s}s")]
+    RateLimited { retry_after_s: u32 },
+
+    #[error("record not found upstream")]
+    NotFound,
+
+    #[error("internal: {0}")]
+    Internal(#[from] anyhow::Error),
+}
+
+/// Byte stream returned by a plugin's `handle_fetch`.
+pub type ByteStream = futures::stream::BoxStream<'static, Result<bytes::Bytes, GatewayError>>;
+
+/// Plugin liveness snapshot surfaced via `/health`. Must not call upstream
+/// — `health()` is invoked on every status poll.
+#[derive(Clone, Debug, Serialize, Deserialize)]
+#[serde(rename_all = "snake_case", tag = "state")]
+pub enum PluginHealth {
+    Ok,
+    Degraded { reason: String },
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn hash_display_and_as_str_match() {
+        let m = Hash("bafy123".to_string());
+        assert_eq!(m.as_str(), "bafy123");
+        assert_eq!(format!("{m}"), "bafy123");
+    }
+
+    #[test]
+    fn discovery_record_roundtrips_through_serde_json() {
+        let r = DiscoveryRecord {
+            upstream_id: "scihub".to_string(),
+            record_id: "10.1038/s41586-021-03819-2".to_string(),
+            fields: BTreeMap::from_iter([
+                ("title".to_string(), "AlphaFold".to_string()),
+                ("year".to_string(), "2021".to_string()),
+            ]),
+        };
+        let j = serde_json::to_string(&r).expect("serialize");
+        let back: DiscoveryRecord = serde_json::from_str(&j).expect("deserialize");
+        assert_eq!(r, back);
+    }
+
+    #[test]
+    fn plugin_health_serialises_with_tag() {
+        let ok = serde_json::to_value(PluginHealth::Ok).unwrap();
+        assert_eq!(ok, serde_json::json!({"state": "ok"}));
+        let bad = serde_json::to_value(PluginHealth::Degraded {
+            reason: "upstream 5xx".into(),
+        })
+        .unwrap();
+        assert_eq!(
+            bad,
+            serde_json::json!({"state": "degraded", "reason": "upstream 5xx"})
+        );
+    }
+}