[Unit]
Description=RDM card reader HTTP bridge (serves card taps for web login)
Documentation=file:/opt/rdm-card-reader/README.md
# The serial device must exist before we start, otherwise the reader opens the
# wrong tty or none at all.
After=dev-serial.device network-online.target
Wants=network-online.target

# Do not restart forever if the reader is genuinely absent. These are [Unit]
# options, not [Service] - systemd ignores them in the wrong section.
StartLimitIntervalSec=60
StartLimitBurst=5

[Service]
Type=simple
User=rdmcard
Group=dialout
WorkingDirectory=/opt/rdm-card-reader

# --serve exposes the card on http://127.0.0.1:8765/api/card
# --port points at the udev alias, so the reader is the same device every boot.
# Autodetect refuses to guess if more than one USB adapter is present, which is
# the safe behaviour: a wrong guess means authenticating the wrong person.
# Add --wheel-dir /opt/rdm-card-reader/wheels to install dependencies offline.
ExecStart=/opt/rdm-card-reader/.venv/bin/rdm-card-reader \
    --serve \
    --port /dev/rdm-reader \
    --mode login \
    --allow-origin https://your.web.app

Restart=always
RestartSec=3

# The bridge only needs to read the serial port and listen on loopback.
NoNewPrivileges=true
PrivateTmp=true
ProtectSystem=strict
ProtectHome=true
ProtectKernelTunables=true
ProtectKernelModules=true
ProtectControlGroups=true
RestrictAddressFamilies=AF_INET AF_INET6 AF_UNIX
RestrictNamespaces=true
LockPersonality=true
MemoryDenyWriteExecute=true
DeviceAllow=/dev/rdm-reader rw
DevicePolicy=closed

# stdout/stderr go here; watch with: journalctl -u rdm-card-reader -f
StandardOutput=journal
StandardError=journal
SyslogIdentifier=rdm-card-reader

[Install]
WantedBy=multi-user.target