ha-freshharvest/docs/internals.md

Internals

How this integration talks to freshharvest.com. Nothing here is needed to use it — see the README for that. This is for anyone changing the code, or working out why it broke.

How it works

Fresh Harvest is not on Shopify, Farmigo, or Local Line — the page metadata reports Vy Technology - Custom Code. It is a server-rendered jQuery site with no JSON API and no mobile app, so this integration signs in and parses HTML.

Login is a two-step handshake:

1. GET /s/popup/login returns the form plus two hidden anti-replay fields, LoginSecurity and SubmitToken, minted per session.
2. POST /s/submit/login with LoginEmail, LoginPassword, both tokens, and an empty Redirect, yielding an fh_session_authenticated cookie.

The tokens are bound to the cookie issued by step 1, so both requests must share a cookie jar.

A refresh is three GETs: /p/dashboard/details for the delivery day, next arrival, both upcoming carts and their totals; /p/dashboard/manage-subscriptions for standing orders; and /p/dashboard/pause-deliveries for vacation holds. Three requests every six hours.

Write actions cost more, because nothing can be constructed offline — every mutating endpoint is guarded by rotating per-render tokens, so each action fetches the page that offers it, reads fresh tokens, checks they describe the intended target, and only then submits.

Markup notes

Six traps, none guessable from the outside:

• HTTP status means nothing. Every /p/* path returns 200, including invented ones. Signed-in state is detected by the presence of a Sign Out control, not by a status code.
• cart-contents-skipped does not mean the order was skipped. It marks the locked cart — the one past its cutoff and arriving next. Treating it as "skipped" reports the wrong delivery as cancelled. The reliable signal for "can still be changed" is a non-empty .cart-customize-wrapper.
• The free-delivery bar only renders on carts below the threshold. An order that already qualifies has no bar at all, so the threshold is read once from whichever cart shows it and applied to every order.
• Popups and AJAX replies are fragments, not pages. They carry no navigation, so a "am I still signed in?" check based on a Sign Out control reads every one of them as logged out. Skip could not run at all until these were fetched with that check disabled.
• openPopup is written both ("x","y") and ("x", "y"). A regex requiring no space silently matches nothing on the pages that use the other form — which is every basket page.
• A <select>'s id is not its POST field. The subscribe form's frequency control is id='FrequencyID' but name='popup-toggle'. Posting FrequencyID is accepted and does nothing.

Consistency guarantees

Two invariants hold against the portal's own arithmetic, and tests assert both:

• next_delivery_box_price + next_delivery_add_ons == next_delivery_subtotal
• open_order_free_delivery_remaining reaching 0.00 always coincides with a 0.00 delivery fee

Drift detection

freshharvest.com has no API and no stability contract — this integration reads HTML and posts to form endpoints, so a redesign can change what a value means without changing its shape. tools/compat.py records every assumption and CI asserts them against the live site daily, refreshing this table and opening an issue on drift.

That covers only what anyone can see. The markup behind the login, where every real break so far has been, is checked by tools/compat_auth.py from a daily workflow that runs only on the maintainer's forge; see the README.