ipodderx-rs/CLAUDE.md

# Working on ipodderx-rs

Notes for whoever picks this up next. Read [docs/architecture.md](docs/architecture.md) for how the
thing is built; this file is about working on it without repeating mistakes that have already been
made here.

## Where things are

Production is the `iPodderX` container on Tower (192.168.1.130), the `ipodderx` service of the
Arcane project `content`: `/mnt/fast/arcane/projects/content/compose.yaml`. That file is what runs;
`docker-compose.yml` in this repo is a copy, and editing it changes nothing in production.

| | Host | In the container |
|---|---|---|
| Image | `192.168.1.130:5000/ipodderx:latest` | |
| Config | `/mnt/fast/appdata/ipodderx/config.toml` | `/config/config.toml` |
| Database | `/mnt/user/ipodderx/state.db` | `/data/state.db` |
| Downloads | `/mnt/user/ipodderx/downloads` | `/downloads` |
| Web UI | `192.168.1.130:8099`, also `ipodderx.sdf1.net` via a Cloudflare tunnel | `0.0.0.0:8099` |
| Sign-in via the tunnel | Cloudflare Access app `ipodderx`, with Authentik as its identity provider; see [docs/sso.md](docs/sso.md) | trusts `Cf-Access-Authenticated-User-Email` from `192.168.16.1`, the `content_default` gateway |

Deploying a change is: build and push the image, then pull it and recreate the container.

```sh
docker buildx build --tag 192.168.1.130:5000/ipodderx:latest . --push
docker compose -f /mnt/fast/arcane/projects/content/compose.yaml pull ipodderx
docker compose -f /mnt/fast/arcane/projects/content/compose.yaml up -d ipodderx
docker logs --tail 20 iPodderX
```

**Name the service.** A bare `up -d` recreates every container in `content`, beets and immich
included. Run `pull` before `up`, because `up` reuses whatever `latest` the host already has.

**A build that fails with `429 Too Many Requests` on a base image** is Docker Hub rate-limiting
this host. There is no Docker Hub login here, and the build asks about `debian:bookworm-slim` and
`rust:1-slim-bookworm` every time unless they are already stored locally. Pull them from Google's
mirror and tag them; the build then uses the local copies without asking Docker Hub:

```sh
docker pull mirror.gcr.io/library/debian:bookworm-slim
docker tag mirror.gcr.io/library/debian:bookworm-slim debian:bookworm-slim
docker pull mirror.gcr.io/library/rust:1-slim-bookworm
docker tag mirror.gcr.io/library/rust:1-slim-bookworm rust:1-slim-bookworm
```

Run those again now and then, or the local copies go stale.

The healthcheck runs `ipx status` against the control socket, so `(healthy)` in `docker ps` means
the daemon answers there and can read its database, not just that the web port is up. The socket
answers `status` itself instead of queuing it behind the worker's current job, so a long scan or
download does not fail the check; it also means a worker stuck on one job would still pass. The
container restarts on its own after a reboot.

Before the container, ipx ran by hand in code-server, with its files in `/config/.config/ipx/` and
`/config/.local/share/ipx/`. Those are still there and the container does not read them. If you run
a daemon by hand for testing, stop it with **`pkill -x ipx`, never `pkill -f ipx`**. `-f` matches
the shell running the command and kills the session (exit 144). This has happened more than once.

## Before you touch the page

`web/index.html` is `include_str!`d into the binary, so **every page change needs a rebuild** before
it is visible. It is one file: markup, CSS and script.

After any edit to it:

```sh
node tests/page-smoke.js
```

That loads the script against a stub DOM and checks every selector it wires at load actually
exists. It exists because a patch once anchored on a deleted function, `String.replace` silently
matched nothing, and the whole UI died with a `ReferenceError` while every server-side test passed.

Patching that file by guessing an anchor string has failed repeatedly. Read the exact block first
(`sed -n 'START,ENDp'`), match it verbatim, and assert the replacement happened rather than hoping.

## Tests

```sh
cargo test                # ~51 tests: parsing, filters, retention, schedules, SQL, per-user state
node tests/page-smoke.js
npx playwright test       # 16 browser tests against a real daemon on fixture feeds
```

Things about the browser suite that have cost time:

* It starts **its own daemon and database** under `/tmp/ipx-ui-test`, wiped once per run. Playwright
  re-imports the config in every worker, so `prepare()` guards on `TEST_WORKER_INDEX` — without
  that guard a worker deleted the database out from under the running daemon, which then kept
  serving from the unlinked inode while everything else saw an empty file.
* Tests **share that daemon and run in order**. A test that opens an item marks it read and changes
  what later tests see. Write assertions that do not depend on what ran before, or normalise the
  state first.
* Fixture feeds must not share an enclosure URL, because `enclosures.url` is globally unique and
  whichever feed is scanned first claims it.
* `webServer` starts **before** `globalSetup`, which is why the fixture config is written at
  config-load time instead.

Non-trivial logic leaves one runnable check behind. Pure functions (`merge_policy`, `pick`,
`matches_keywords`, `parse_interval`) are the easiest place to put it.

## Things that are true and easy to get wrong

* **`enclosures.url` is globally UNIQUE.** It is the dedupe key and the reason one file serves every
  subscriber. Two feeds publishing the same URL means only the first one scanned shows it.
* **Read state lives in `entry_state`, per user, and nowhere else.** `entries` had `read`, `flagged`
  and `position` columns from before accounts; two bugs came from queries still reading them
  (retention, and the entry pruner), and `migrate()` now drops them.
* **The catalogue is config.toml; the subscriptions are in the database.** A feed exists once;
  `subscriptions(user_id, feed_id)` says who wants it and with what settings. OPML children are
  derived and never written to config.
* **One fetch serves everyone**, so scan policy is a union of subscribers' wants (`merge_policy`).
  Anyone wanting an item is enough to fetch it.
* **The UI hiding a control is not enforcement.** Admin-only actions check `user.is_admin` in the
  handler and return `403`.
* **A `tokio::select!` only races its branches at the point of selection.** A long download has to
  watch the shutdown channel itself; the daemon ignored SIGTERM for exactly this reason.
* Only one daemon per socket. Removing the socket file defeats the guard and you get two daemons
  fighting over the database, with the stale one still holding the port.
* `/api/settings` answering `200` does **not** mean the daemon is well — the web server is a
  different task. `ipx status` checks the control socket and the database; to see the worker
  getting through its jobs, watch for `scan complete` in the log.
* **Every `ipx` command runs `migrate()` when it opens the database**, the healthcheck's
  `ipx status` included. A migration that rewrites a big table (`DROP COLUMN`) takes seconds on
  production, and a command run meanwhile fails with `migrating schema`. It changes nothing; wait
  for `daemon started` in the log. Copy `state.db` aside before deploying one.

## House style

Comments explain **why**, not what. If a line looks odd, the comment says what went wrong without
it. No emoji, no exclamation marks, no "obviously". Prose in the UI and docs is plain English and
addressed to the person using it.

Every change gets one line under `## [Unreleased]` in [CHANGELOG.md](CHANGELOG.md), in its
[Keep a Changelog](https://keepachangelog.com/en/1.1.0/) group: Added, Changed, Deprecated,
Removed, Fixed or Security. Say it the way someone using ipx would notice it. When there is more to
say, such as what was wrong before or what it cost to find out, write it up at the top of
[docs/history.md](docs/history.md), dated. That record has been more useful than the git log more
than once.

Cutting a release: rename `[Unreleased]` to `## [X.Y.Z] - YYYY-MM-DD` and open a new empty
`[Unreleased]` above it, bump `version` in `Cargo.toml`, tag the commit `vX.Y.Z`, and update the
compare links at the bottom of the changelog.

Deliberate simplifications get a `ponytail:` comment naming the ceiling and the upgrade path, e.g.
`// ponytail: global connection mutex, move to a pool if feed count makes it contend`.

## Known gaps

* Cloudflare's `Cf-Access-Jwt-Assertion` is not verified — ipx trusts the hop plus `trusted_proxies`
  (documented in [docs/sso.md](docs/sso.md)).
* A feed's `<description>` subtitle is dropped whenever `content:encoded` exists, which loses
  Substack-style subtitles.