User accounts and NFC

User accounts and NFC

User accounts are optional. With the feature disabled, Smart Drink Fridge continues to work exactly as before: no login is shown, camera scans are anonymous, and no NFC reader is required.

Enable accounts

Open Settings → User accounts and create the first administrator. Enabling the feature requires the current STORNO_PASSWORT, which prevents another network user from taking control of an unconfigured installation.

Administrators can then create accounts with:

• A display name
• A unique login name
• A PIN or password
• The User or Administrator role
• An optional NFC card

PINs and passwords are stored as one-way hashes. NFC card identifiers are stored as keyed hashes and are not saved in their original form.

Web login

Users can sign in through the web interface with their login name and PIN or password. A signed-in user receives a personal overview of consumption and costs for the last 30 days.

Keyboard-style RFID readers can also enter a card on the login page. A PC/SC reader connected directly to a headless Docker host uses the separate NFC service instead.

ACS ACR122U and other PC/SC readers

The exact ACS ACR122U used for development and testing is available through this Amazon product link. Product listings can change, so verify the model name before ordering.

Connect the reader to the Docker host and start:

docker compose --profile scanner --profile nfc up -d

Check the service when a card is not recognized:

docker compose --profile nfc ps
docker compose logs --tail=100 nfc
lsusb

NFC selects a user; it does not scan drink barcodes. After a known card is presented, that user is selected for 120 seconds or until the next successful camera barcode removal.

With the optional Nextion display, a user can alternatively tap Sign in with PIN, select an active account, and enter the same PIN used for web login. The PIN is verified against the existing one-way hash and is never stored or printed in logs. NFC and display PIN login set the same temporary scanner user.

Scanner sign-in policy

The option Block drink scans without a selected user is a separate setting and is off by default:

• Accounts off: anonymous scanning works normally.
• Accounts on, policy off: identified scans are attributed; all other scans remain unassigned.
• Accounts on, policy on: a user must first be selected by web login, NFC, or the optional Nextion PIN screen. Otherwise the scan is rejected and stock does not change.

Disabling user accounts also disables the scanner policy automatically.

Optional checkout home screen

Administrators can enable the checkout-style start page under Settings. When enabled, the normal flow starts with selectable user tiles and PIN login or NFC identification. A checkout login page waiting in the browser detects a recent physical NFC selection and opens that user's checkout automatically; the raw card identifier never reaches the browser. The signed-in user then sees touch-friendly drink tiles with product image, name, current stock, and quantity selection. Confirming a tile removes the selected quantity and attributes the booking to that user.

This mode is optional and appears only while user accounts are enabled. The normal inventory dashboard remains available through its own navigation link.

Assign older or anonymous bookings

Administrators can open Settings → User accounts and assign an unassigned consumption booking to an active user. This supports both historical bookings and anonymous bookings made while the strict scanner policy was disabled.

Disable accounts

Use Disable user accounts in the same settings page. Existing users and booking attribution remain stored so the feature can be enabled again later, but login enforcement and the strict scanner policy are switched off.

NFC cards are convenient identifiers, not proof of identity. Many low-cost cards can be cloned; do not rely on them as the only protection for administrative actions.