Extending

Every policy is a dotted path. Common extension points:

Attendance processor

from fingerprint_attendance.processing.default import FirstInLastOutProcessor

class PairedHoursProcessor(FirstInLastOutProcessor):
    version = "paired-1"

    def build_context(self, enrollee, work_date, punches):
        ctx = super().build_context(enrollee, work_date, punches)
        pairs = zip(punches[::2], punches[1::2])
        ctx.worked = sum((o.punched_at - i.punched_at for i, o in pairs), timedelta())
        return ctx

FINGERPRINT_ATTENDANCE["ATTENDANCE_PROCESSOR"] = "myapp.processing.PairedHoursProcessor"

Implement BaseAttendanceProcessor.process_day(enrollee, work_date, create_empty=False) from scratch if you want full control. process_range, recompute and process_pairs are provided. Set ATTENDANCE_PROCESSOR = None to disable processing and compute attendance yourself from Punch rows (Punch.objects.effective() excludes soft duplicates).

Sync strategy

from fingerprint_attendance.sync.strategies import BaseSyncStrategy

class SiteStrategy(BaseSyncStrategy):
    def devices_for(self, enrollee):
        return Device.objects.active().filter(location=enrollee.employee.site)

    def enrollees_for(self, device):          # optional, for fast backfills
        return Enrollee.objects.active().filter(employee__site=device.location)

A plain function (enrollee) -> QuerySet[Device] also works.

Punch state resolver

from fingerprint_attendance.ingestion.state import BasePunchStateResolver

class WorkCodeResolver(BasePunchStateResolver):
    def resolve(self, candidates, context):
        for c in candidates:
            c.state = "overtime_in" if c.work_code == "9" else "check_in"

Set needs_history = True to use context.previous_punch_count(candidate).

Dedupe key

DEDUPE_KEY_BUILDER = "myapp.dedupe.key" with key(candidate) -> str. The default is serial|pin|UTC second.

Protocol adapter

from fingerprint_attendance.adms.adapter import ADMSProtocolAdapter

class MyFirmwareAdapter(ADMSProtocolAdapter):
    def render_set_time(self, device, local):
        return f"SET OPTION DateTime={local:%Y%m%d%H%M%S}"

    def parse_attlog_line(self, line):
        return super().parse_attlog_line(line.replace(";", "\t"))

Set it globally with ADMS_PROTOCOL_ADAPTER, or per device with device.options["protocol_adapter"]. Add commands with adms.commands.command_registry.register(CommandSpec(...)).

API

Use SERIALIZER_OVERRIDES, VIEWSET_OVERRIDES, FILTERSET_OVERRIDES, per-action permissions, and the authentication, pagination and throttle settings. See REST API. Subclass the shipped classes in fingerprint_attendance.api to keep their behaviour.

Models

Concrete models are thin subclasses of the abstract bases in fingerprint_attendance.models.abstract. Reuse them for your own tables, and override the relation fields, whose reverse names must be unique. Swapping the package's concrete models is not supported; extend with one-to-one profile models instead.

Everything else

Template storage (TEMPLATE_STORAGE_BACKEND, e.g. a vault), PIN generation, day boundaries, calendar, holiday, leave and schedule providers, the realtime backend and group names, the webhook sender, and the task backend. See the configuration reference.

Service layer

Everything the API does is available as a function in fingerprint_attendance.services, so you can call it from your own views, admin actions or scripts.