import datetime
import os
from typing import Optional, Union, List, Dict, Any
from sqlalchemy import create_engine, Column, Integer, String, DateTime
from sqlalchemy.orm import sessionmaker, scoped_session
from platypush.backend import Backend
from platypush.common.db import declarative_base
from platypush.config import Config
from platypush.context import get_plugin
from platypush.message.event.covid19 import Covid19UpdateEvent
from platypush.plugins.covid19 import Covid19Plugin
Base = declarative_base()
Session = scoped_session(sessionmaker())
[docs]class Covid19Update(Base):
"""Models the Covid19Data table"""
__tablename__ = 'covid19data'
__table_args__ = {'sqlite_autoincrement': True}
country = Column(String, primary_key=True)
confirmed = Column(Integer, nullable=False, default=0)
deaths = Column(Integer, nullable=False, default=0)
recovered = Column(Integer, nullable=False, default=0)
last_updated_at = Column(DateTime, nullable=False, default=datetime.datetime.utcnow)
[docs]class Covid19Backend(Backend):
"""
This backend polls new data about the Covid-19 pandemic diffusion and triggers events when new data is available.
Triggers:
- :class:`platypush.message.event.covid19.Covid19UpdateEvent` when new data is available.
"""
# noinspection PyProtectedMember
[docs] def __init__(
self,
country: Optional[Union[str, List[str]]],
poll_seconds: Optional[float] = 3600.0,
**kwargs
):
"""
:param country: Default country (or list of countries) to retrieve the stats for. It can either be the full
country name or the country code. Special values:
- ``world``: Get worldwide stats.
- ``all``: Get all the available stats.
Default: either the default configured on the :class:`platypush.plugins.covid19.Covid19Plugin` plugin or
``world``.
:param poll_seconds: How often the backend should check for new check-ins (default: one hour).
"""
super().__init__(poll_seconds=poll_seconds, **kwargs)
self._plugin: Covid19Plugin = get_plugin('covid19')
self.country: List[str] = self._plugin._get_countries(country)
self.workdir = os.path.join(
os.path.expanduser(Config.get('workdir')), 'covid19'
)
self.dbfile = os.path.join(self.workdir, 'data.db')
os.makedirs(self.workdir, exist_ok=True)
def __enter__(self):
self.logger.info('Started Covid19 backend')
def __exit__(self, exc_type, exc_val, exc_tb):
self.logger.info('Stopped Covid19 backend')
def _process_update(self, summary: Dict[str, Any], session: Session):
update_time = datetime.datetime.fromisoformat(
summary['Date'].replace('Z', '+00:00')
)
self.bus.post(
Covid19UpdateEvent(
country=summary['Country'],
country_code=summary['CountryCode'],
confirmed=summary['TotalConfirmed'],
deaths=summary['TotalDeaths'],
recovered=summary['TotalRecovered'],
update_time=update_time,
)
)
session.merge(
Covid19Update(
country=summary['CountryCode'],
confirmed=summary['TotalConfirmed'],
deaths=summary['TotalDeaths'],
recovered=summary['TotalRecovered'],
last_updated_at=update_time,
)
)
def loop(self):
# noinspection PyUnresolvedReferences
summaries = self._plugin.summary(self.country).output
if not summaries:
return
engine = create_engine(
'sqlite:///{}'.format(self.dbfile),
connect_args={'check_same_thread': False},
)
Base.metadata.create_all(engine)
Session.configure(bind=engine)
session = Session()
last_records = {
record.country: record
for record in session.query(Covid19Update)
.filter(Covid19Update.country.in_(self.country))
.all()
}
for summary in summaries:
country = summary['CountryCode']
last_record = last_records.get(country)
if (
not last_record
or summary['TotalConfirmed'] != last_record.confirmed
or summary['TotalDeaths'] != last_record.deaths
or summary['TotalRecovered'] != last_record.recovered
):
self._process_update(summary=summary, session=session)
session.commit()
# vim:sw=4:ts=4:et:
