backend_fiesta/POS_LOGIN.md

# Nearle POS — Terminal Sign-In

How a till authenticates, and how it finds out which shop it belongs to.

**Base URL** `https://fiesta.nearle.app/live/api/v1/pos`
**Live since** 6 Aug 2026, `v1.3.98`

---

## What changed, and why it matters

A terminal used to hold a store id typed into Settings and a password compiled
into the app. That made the store id a **claim** rather than a fact: any till
could name any outlet and be believed, so changing one number on one screen
moved a terminal into another tenant's books. The password was identical on
every install of a build.

Now a person signs in with their own back-office account, and the outlet
arrives **as a consequence** — sealed inside a signed token the terminal cannot
edit, and re-checked by the server on every request.

The rule to hold onto: **the till no longer decides which shop it is. It is
told.**

---

## Quickstart

```bash
BASE=https://fiesta.nearle.app/live/api/v1/pos

# 1. Sign in
curl -s -X POST $BASE/login \
  -H 'Content-Type: application/json' \
  -d '{"authname":"rsselvapuram@gmail.com","password":"…","terminal_id":"T5EDD"}'

# 2. Use the token on everything else
curl -s $BASE/session -H "Authorization: Bearer $TOKEN"
```

---

## The flow

These steps are in order, and the order matters.

**1. Sign in.** `POST /login` with the operator's own credentials — the same
`app_users` account they use for the web console. There is no separate POS
password.

**2. Read `store_id` out of the response.** Do not ask anyone to type it. It is
whatever the back office says that account's outlet is.

**3. If `locations` has more than one entry, ask which one.** Only then. A
single-outlet account gets a list of one and must never see a picker.

**4. Save the token.** Platform keystore, not a plain file or SQLite — it is a
bearer credential for a whole trading day. Restore it on launch **before** any
upload or catalogue pull runs.

**5. Send it on every request** as `Authorization: Bearer <token>`.

**6. Import `staff`.** Replace the till's local staff with what came down, and
deactivate anything that wasn't in the list. That is what retires the built-in
PINs.

---

## `POST /login`

The only unauthenticated route. It is where a token comes from.

### Request

```json
{
  "authname": "rsselvapuram@gmail.com",
  "password": "…",
  "terminal_id": "T5EDD",
  "device_id": "a5f3…",
  "location_id": 1135,
  "configid": 1
}
```

| Field | Required | Notes |
|---|---|---|
| `authname` | yes* | Email. **Or** send `contactno` instead. |
| `contactno` | yes* | Mobile number, as an alternative to `authname`. |
| `password` | yes | |
| `terminal_id` | no | This till's short code, e.g. `T5EDD`. Recorded on the session. |
| `device_id` | no | The device's stable UUID. |
| `location_id` | no | **Only** meaningful for a multi-outlet account. A request, not an assertion — it is checked against what the account may reach. |
| `configid` | no | Inferred when absent. Send it only if you get the ambiguity error below. |

\* one of `authname` or `contactno`.

### Response — `200`

```json
{
  "code": 200,
  "status": true,
  "message": "Login successful",
  "details": {
    "token": "eyJ1aWQiOjEy….K3p9",
    "expires_at": "2026-09-05T10:51:17Z",

    "user_id": 1229,
    "full_name": "Selvapuram",
    "email": "rsselvapuram@gmail.com",
    "role_id": 0,

    "tenant_id": 1087,
    "tenant_name": "Ragul Stores",

    "store_id": "1135",
    "location_id": 1135,
    "location_name": "Ragul stores Selvapuram",
    "gstin": "123456",
    "address": "…",
    "phone": "…",

    "locations": [
      { "location_id": 1135, "location_name": "Ragul stores Selvapuram",
        "address": "", "city": "", "status": "Active" }
    ],

    "staff": [
      { "user_id": 1148, "full_name": "Ragul Kannan",
        "role": "Super admin", "pin": "1111", "status": "Active" }
    ]
  }
}
```

### The fields that matter

**`store_id`** — a string, because that is the shape every uplink already
sends. Use it verbatim as the `store_id` on `/orders`, `/customers` and
`/catalogue`. It is the same value as `location_id`, handed back in the form it
will be replayed in.

**`token`** — **opaque**. Do not parse it, do not read anything out of it, do
not trust anything it appears to say. Its only correct use is to hand it back.

**`expires_at`** — 30 days out. Long on purpose: a shop signs a terminal in once
and expects it to keep working. Forcing a re-login mid-shift means a queue of
customers waiting while somebody finds the manager.

**`gstin` / `address` / `phone`** — print these on the receipt. They are a legal
requirement on a GST invoice and they used to be compile-time constants, so a
shop correcting its GSTIN had to wait for a rebuild. Write them locally on
sign-in.

**`locations`** — every outlet this account may open a till at. Length 1 is the
normal case.

**`staff`** — see [Staff and PINs](#staff-and-pins). **Often empty.**

---

## `GET /session`

Answers who the caller is, per their token. What a till calls on launch to
check whether yesterday's session is still good, without making a real request
and interpreting the failure.

Requires the token. Returns `401` when there isn't one.

```json
{
  "code": 200,
  "status": true,
  "details": {
    "user_id": 1229,
    "tenant_id": 1087,
    "location_id": 1135,
    "store_id": "1135",
    "role_id": 0,
    "terminal_id": "PROBE",
    "expires_at": "2026-09-05T10:51:17Z"
  }
}
```

---

## `GET /staff`

Who may ring a bill at this terminal's outlet. For pulling down somebody hired
mid-shift without signing the terminal out.

**Takes no parameters.** The answer carries PINs, so the outlet comes from the
caller's own token — a till must not be able to ask who works at the shop next
door. A request without a token is refused whatever the enforcement setting is.

```json
{
  "code": 200,
  "status": true,
  "details": {
    "location_id": 1135,
    "staff": []
  }
}
```

---

## Using the token

```
Authorization: Bearer eyJ1aWQiOjEy….K3p9
```

`X-Pos-Token: <token>` is accepted as a fallback, because some shop routers
strip `Authorization` headers over plain HTTP. A bare token with no `Bearer `
prefix is tolerated too.

Send it on **every** POS call: `/orders`, `/customers`, `/catalogue`, `/health`,
`/sales*`, `/session`, `/staff`.

### What the server checks

1. The token verifies against our signing key and has not expired.
2. The outlet named in the request belongs to the token's tenant.

The second is the one that matters. A valid token is a licence to name **your**
outlets, not any outlet. The outlet is read from the query string *and* from the
JSON body, because `/orders` and `/customers` carry `store_id` in the batch and
never in the URL.

```
GET /catalogue?store_id=1135  →  200   your outlet
GET /catalogue?store_id=1185  →  403   {"message":"this session cannot reach outlet 1185"}
```

---

## Errors

### Sign-in

| Code | Meaning | What the till should do |
|---|---|---|
| `400` | Body unreadable, or neither `authname` nor `contactno` sent | Fix the request |
| `401` | `those sign-in details were not recognised` | Ask them to re-type. **Wrong email and wrong password give the same message** — deliberately, so the endpoint isn't a directory of who banks here |
| `403` | Real account, but it can't open this till | Show the message; re-typing won't help |

The `403` messages, verbatim:

- `this account is inactive; contact your administrator`
- `this account has no password set; set one in the web console first`
- `this account is not attached to a tenant and cannot open a till`
- `no active outlet is registered for this account`
- `this account cannot open a till at outlet 1185`
- `more than one account uses these sign-in details; ask your administrator for the configid and send it with the login`

That last one is real, not theoretical: `authname` is not unique in this schema.
Live data has the same address twice. We refuse rather than pick one, because
picking wrong means billing into another tenant's books.

### Authenticated routes

| Code | Meaning |
|---|---|
| `401` | No token, malformed token, bad signature, or expired — sign in again |
| `403` | Valid token naming an outlet the tenant doesn't own |

---

## Multi-outlet accounts

An account pinned to one location gets that location. An account with no
location — a proprietor with several shops — gets all of the tenant's active
outlets.

```
rsselvapuram@gmail.com  →  1 outlet   (1135, Selvapuram)
raguladmin@gmail.com    →  6 outlets  (1097, 1135, 1137, 1138, 1139, 885536644)
```

When `locations.length > 1`:

1. Show a picker. **Don't make it dismissable** — a terminal has to be standing
   somewhere, and silently defaulting to the first outlet is how a day's takings
   get filed against the wrong shop.
2. Sign in **again** with `location_id` set to their choice.

Re-signing-in is not laziness. The outlet is inside the signed token, so only
the server can issue one for a different shop — and re-checking entitlement at
that moment is the point.

---

## Staff and PINs

Two different credentials, easily confused:

| | Says | Checked by |
|---|---|---|
| **Sign-in** (email + password) | which **shop** this terminal is | the server |
| **PIN** | which **person** rang this bill | the terminal, offline |

The PIN stamps `cashiername` and is what shifts settle against. It is **shift
attribution, not a security boundary** — the boundary is the token.

### The PIN comes down in the clear

Over TLS, and that's considered rather than sloppy. Four digits are
brute-forceable in microseconds whatever they're wrapped in, so hashing
server-side would buy the appearance of strength and not the substance — while
costing something real, because the terminal salts every PIN with its own random
salt before storing it and could never verify a hash computed on the server.

**Store it hashed on the device.** It arrives in the clear; it must not sit that
way.

### Importing

Write everyone in `staff`, keyed on `user_id` so a re-sync updates rather than
duplicates. Then **deactivate everything you didn't just import** — that is what
kills the built-in PINs. Deactivate, never delete: bills carry the cashier's
name.

### :warning: `staff` is usually empty today

Only 116 of 596 accounts on the platform have a PIN set. Outlet 1135 — the one
the terminal ships pointed at — has **zero**.

So:

- **An empty list is not a failure.** Do nothing and leave the till exactly as
  it was.
- **A list where every PIN is unusable** (`0`, blank) must behave the same way.
  Deactivating the local accounts because the back office isn't filled in yet
  would leave a counter nobody can sign in to.

The terminal still ships with three seeded logins for exactly this reason. They
retire automatically the moment real staff exist. Filling in real PINs in the
back office is what makes that happen.

---

## Current state

| | |
|---|---|
| Endpoints | live on `v1.3.98`, all three pods |
| Signing key | set in `app-secrets` |
| **Enforcement** | **OFF** — `POS_AUTH_REQUIRED` is unset |

Enforcement being off means a request carrying **no** token is still allowed
through, so terminals already trading don't stop the day this ships. It does
**not** mean tokens are ignored:

- a token that's present and invalid is **always** refused;
- a valid token naming another tenant's outlet is **always** refused.

Once the fleet is on a build that signs in, `POS_AUTH_REQUIRED=true` closes the
door on untokened requests.

---

## Known limitations

- **Passwords are stored in plaintext** across the whole platform, not just
  here. Fixing it is a migration touching every login path.
- **No role check.** Any active account with a tenant, a password and an active
  outlet can open a till — including `roleid 0`, which isn't in `app_roles` at
  all and currently includes a delivery rider. The damage is bounded by the
  token: they can only reach their own tenant's books.
- **`1135` means two different things.** It's a *location* (Ragul stores
  Selvapuram, under tenant 1087) and separately a *tenant* (Suriya Store). Same
  number, different tables. Watch for it in logs.