Source code for exporter.models

import uuid
from datetime import datetime
from pathlib import Path
from typing import Optional

from django.conf import settings
from django.db import models
from django.utils import timezone

from exporter.storages import HMRCStorage
from hmrc_sdes.api_client import HmrcSdesClient
from taric.models import Envelope


def to_hmrc(instance: "Upload", filename: str):
    """Generate the filepath to upload to HMRC."""
    return str(Path(settings.HMRC_STORAGE_DIRECTORY) / filename)


class Upload(models.Model):
    """Represents a TARIC differential update file upload to HMRC."""

    file = models.FileField(storage=HMRCStorage, upload_to=to_hmrc)
    envelope = models.ForeignKey(Envelope, on_delete=models.PROTECT)
    correlation_id = models.UUIDField(default=uuid.uuid4, editable=False)
    checksum = models.CharField(max_length=32, editable=False)
    notification_sent = models.DateTimeField(editable=False, null=True)
    created_date = models.DateTimeField(auto_now_add=True, editable=False, null=True)

    # Max size is 50 megabytes
    MAX_FILE_SIZE = 50 * 1024 * 1024

    def notify_hmrc(self, now: Optional[datetime] = None):
        """
        :param now: datetime to set notification_sent to, defaults to now.

        :throws and APIRequestError: if the end-point cannot be contacted.
        """
        client = HmrcSdesClient()
        client.notify_transfer_ready(self)

        if now is None:
            now = timezone.now()
        self.notification_sent = now
        self.save()

    @property
    def filename(self):
        return f"DIT{str(self.envelope.envelope_id)}.xml"

    @property
    def notification_payload(self):
        return {
            "informationType": "EDM",
            "correlationID": str(self.correlation_id),
            "file": {
                "fileName": self.filename,
                "fileSize": self.file.size,
                "checksum": self.checksum,
                "checksumAlgorithm": "MD5",
            },
        }