CRoC Drinks Tab

Simple localhost web app for drinks balances.

What members can do

• Search by name or student number.
• Scan a barcode with a physical scanner into the search bar.
• Search accepts scanner values with a 3-character prefix before the stored student number.
• Clear the search with one button.
• Buy one drink (-$1.00) from their balance.
• Student numbers are searchable but hidden in the public members table.

What admin can do

• Add members.
• Remove members.
• Search and select a member to edit.
• Update name and student number.
• Add/subtract from existing balance.
• Update the drink price.
• Admin auto-locks when switching back to the Members tab.
• Export current members database to CSV.
• Initialize/replace database from exported CSV.

Local run (manual)

From this folder:

python3 server.py

Open:

• http://127.0.0.1:8000

The Members search box is designed for a keyboard-wedge barcode scanner. It stays focused, accepts scanned values like xxx12345678, strips the 3-character prefix for matching, allows normal keyboard typing, and auto-clears after 1 minute.

Database file is local SQLite at:

• ./drinks_tab.db

All member changes are logged in:

• member_audit_log table (add/edit/purchase/remove/balance changes)

Ubuntu auto-start on boot (recommended)

Install as a system service:

cd /absolute/path/to/drinks_tab
sudo bash deploy/install_system_service.sh

If you previously installed an older unit file, reinstall to overwrite it:

sudo systemctl disable --now croc-drinks-tab.service
cd /absolute/path/to/drinks_tab
sudo bash deploy/install_system_service.sh

Service commands:

sudo systemctl start croc-drinks-tab.service
sudo systemctl stop croc-drinks-tab.service
sudo systemctl restart croc-drinks-tab.service
sudo systemctl status croc-drinks-tab.service
sudo journalctl -u croc-drinks-tab.service -f

Disable auto-start:

sudo systemctl disable croc-drinks-tab.service

If the service shows running but frontend cannot connect, verify on the laptop:

curl -v http://127.0.0.1:8000/api/members
sudo systemctl status croc-drinks-tab.service --no-pager -l
sudo journalctl -u croc-drinks-tab.service -n 120 --no-pager

Logs

Runtime/service logs (server stdout/stderr) are in systemd journal:

sudo journalctl -u croc-drinks-tab.service
sudo journalctl -u croc-drinks-tab.service -f

Member activity logs (add/edit/purchase/remove/balance changes) are stored in SQLite table member_audit_log inside ./drinks_tab.db.

Example query:

sqlite3 ./drinks_tab.db \
"SELECT datetime(event_time_ms/1000,'unixepoch','localtime'), action, actor, member_name, balance_before, balance_after, balance_delta FROM member_audit_log ORDER BY id DESC LIMIT 20;"

API used by the webpage

• GET /api/members?search=<name_or_student_number>
• POST /api/purchase body: { "id": 1 }
• POST /api/admin/login header: X-Admin-Password: ****
• POST /api/admin/add header: X-Admin-Password: ****
• POST /api/admin/remove header: X-Admin-Password: ****
• POST /api/admin/edit-member header: X-Admin-Password: ****
  • body: { "id": 1, "name": "Alice", "studentNumber": "12345678", "balanceDelta": 2.0 }
• GET /api/admin/export-csv header: X-Admin-Password: ****
• POST /api/admin/import-csv header: X-Admin-Password: ****
  • body: { "csv": "Name,StudentNumber,Balance\\nAlice,12345678,5.00\\n" }
• POST /api/admin/set-drink-price header: X-Admin-Password: ****
  • body: { "drinkPrice": 1.50 }