blechreiz-website/eventplanner_gcal/models.py

import logging
import uuid
from eventplanner.models import Event
from django.contrib.auth.models import User

from apiclient.channel import Channel
from django.db import models

logger = logging.getLogger(__name__)


class UserGCalCoupling(models.Model):
    # For every user in this table the gcal coupling is activated
    user = models.OneToOneField(User, on_delete=models.CASCADE)
    email = models.CharField(max_length=1024)


class GCalMapping(models.Model):
    """Mapping between event id at google and local event id"""
    gcal_id = models.CharField(max_length=64)
    event = models.OneToOneField(Event, primary_key=True, on_delete=models.CASCADE)


class GCalPushChannel(models.Model):
    """This table has either zero or one entry. Required to store if a channel already exists,
       when it expires and how to stop (renew) the channel
    """

    id = models.CharField(max_length=128, primary_key=True)
    address = models.CharField(max_length=256)
    token = models.CharField(max_length=128)
    resource_id = models.CharField(max_length=128)
    expiration = models.IntegerField()

    def to_google_channel(self):
        return Channel('web_hook', self.id, self.token, self.address, self.expiration, resource_id=self.resource_id)

    @staticmethod
    def from_google_channel(google_channel):
        return GCalPushChannel(id=google_channel.id,
                               address=google_channel.address,
                               token=google_channel.token,
                               expiration=google_channel.expiration,
                               resource_id=google_channel.resource_id)

    @staticmethod
    def create_new(callback_url, service, ttl=None):
        gChannel = Channel('web_hook', str(uuid.uuid4()), 'blechreizGcal', callback_url, params={'ttl': int(ttl)})
        response = service.events().watch(calendarId='primary', body=gChannel.body()).execute()
        gChannel.update(response)

        dbChannel = GCalPushChannel.from_google_channel(gChannel)
        dbChannel.save()

    @staticmethod
    def stop(service, google_channel):
        channel_service = service.channels()
        channel_service.stop(body=google_channel.body()).execute()
        GCalPushChannel.from_google_channel(google_channel).delete()