77 lines
2.9 KiB
Markdown
77 lines
2.9 KiB
Markdown
# Flowtrack
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A private, self-hosted period tracker. It logs period days with flow and
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symptoms, predicts the next six periods, and estimates the fertile window.
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It installs on a phone home screen as a web app.
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The app has no runtime dependencies beyond the Python standard library, and it
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stores everything in one SQLite file. Nginx and Authelia provide the access
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boundary.
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## Predictions
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- Periods are runs of logged period days. Spotting doesn't count, and one
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missing day inside a run doesn't split it.
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- The cycle length is a weighted average of up to the last 12 cycles, with
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recent cycles counting more. Cycles shorter than 15 days or longer than 60
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are left out because they usually mean a log was missed.
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- Each prediction is a range of ± the cycle's standard deviation (at least 2
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days, or 4 with fewer than three cycles). The range widens with √n for later
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cycles.
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- Ovulation is estimated 14 days before the next period. The fertile window
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runs from 5 days before ovulation to 1 day after. These are estimates, not
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contraception.
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- Once the expected day passes, the next period is expected from tomorrow,
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and later predictions move with it.
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The logic lives in `static/cycle.js` and is tested in `tests/test_cycle.js`.
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## Notifications
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Web Push, sent by `notify.js` (Node, no dependencies: built-in crypto and
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SQLite). It reuses `static/cycle.js`, so reminders always match the app.
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- `flowtrack-notify daily` runs once a day. It sends "period expected soon"
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once per cycle, `remindDays` (1-7, default 2) before the predicted start,
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and "period is late" once per cycle after the expected day passes.
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- The owner turns notifications on per device in Settings, where there is
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also a test button. On iPhone this only works from the Home Screen app
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(iOS 16.4 or later).
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- The VAPID key pair is created on first start and stored in the database.
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Replacing it invalidates every subscription.
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- The server only accepts subscriptions on Apple, Google, Mozilla and
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Microsoft push hosts, because it POSTs to whatever endpoint it stores.
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Enable it with `--push-contact https://your.site` (the NixOS module does
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this through `push.contact`).
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## Access
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Nginx must overwrite `Remote-User` with the Authelia username. Users listed
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with `--editor` can log and export. Users listed with `--viewer` see period
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days and predictions only. They also see flow and symptoms if the owner turns
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on sharing in Settings. Everyone else gets 403.
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## Run locally
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```sh
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python3 app.py --database /tmp/flowtrack.sqlite3 --editor me --dev-user me
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```
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Then open `http://127.0.0.1:8093`.
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## NixOS module
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```nix
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services.flowtrack = {
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enable = true;
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editors = [ "kayla" ];
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viewers = [ "fred" ];
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backup.directory = "/mnt/disk2/backups/flowtrack"; # nightly, keeps 30
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push.contact = "https://flowtrack.example.org";
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push.time = "*-*-* 09:00:00 Europe/London";
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};
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```
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`python3 app.py --database DB --backup-to DIR --keep N` takes a consistent
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snapshot by hand.
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