cached/weather_forecast.py

   1 #!/usr/bin/env python3
   2
   3 from dataclasses import dataclass
   4 import datetime
   5 import logging
   6 import os
   7 import urllib.request
   8
   9 import astral  # type: ignore
  10 from astral.sun import sun  # type: ignore
  11 from bs4 import BeautifulSoup  # type: ignore
  12 import pytz
  13
  14 import argparse_utils
  15 import config
  16 import datetime_utils
  17 import dateparse.dateparse_utils as dp
  18 import persistent
  19 import text_utils
  20
  21 logger = logging.getLogger(__name__)
  22
  23 cfg = config.add_commandline_args(
  24     f'Cached Weather Forecast ({__file__})',
  25     'Arguments controlling detailed weather rendering'
  26 )
  27 cfg.add_argument(
  28     '--weather_forecast_cachefile',
  29     type=str,
  30     default=f'{os.environ["HOME"]}/cache/.weather_forecast_cache',
  31     metavar='FILENAME',
  32     help='File in which to cache weather data'
  33 )
  34 cfg.add_argument(
  35     '--weather_forecast_stalest_acceptable',
  36     type=argparse_utils.valid_duration,
  37     default=datetime.timedelta(seconds=7200),   # 2 hours
  38     metavar='DURATION',
  39     help='Maximum acceptable age of cached data.  If zero, forces a refetch'
  40 )
  41
  42
  43 @dataclass
  44 class WeatherForecast:
  45     date: datetime.date                # The date
  46     sunrise: datetime.datetime         # Sunrise datetime
  47     sunset: datetime.datetime          # Sunset datetime
  48     description: str                   # Textual description of weather
  49
  50
  51 @persistent.persistent_autoloaded_singleton()
  52 class CachedDetailedWeatherForecast(object):
  53     def __init__(self, forecasts = None):
  54         if forecasts is not None:
  55             self.forecasts = forecasts
  56             return
  57
  58         now = datetime_utils.now_pacific()
  59         self.forecasts = {}
  60
  61         # Ask the raspberry pi about the outside temperature.
  62         www = None
  63         try:
  64             www = urllib.request.urlopen(
  65                 "http://10.0.0.75/~pi/outside_temp",
  66                 timeout=2,
  67             )
  68             current_temp = www.read().decode("utf-8")
  69             current_temp = float(current_temp)
  70             current_temp *= (9/5)
  71             current_temp += 32.0
  72             current_temp = round(current_temp)
  73         except Exception:
  74             logger.warning('Timed out reading 10.0.0.75/~pi/outside_temp?!')
  75             current_temp = None
  76         finally:
  77             if www is not None:
  78                 www.close()
  79
  80         # Get a weather forecast for Bellevue.
  81         www = urllib.request.urlopen(
  82             "https://forecast.weather.gov/MapClick.php?lat=47.652775&lon=-122.170716"
  83         )
  84         forecast_response = www.read()
  85         www.close()
  86
  87         soup = BeautifulSoup(forecast_response, "html.parser")
  88         forecast = soup.find(id='detailed-forecast-body')
  89         parser = dp.DateParser()
  90
  91         said_temp = False
  92         last_dt = now
  93         dt = now
  94         for (day, txt) in zip(
  95                 forecast.find_all('b'),
  96                 forecast.find_all(class_='col-sm-10 forecast-text')
  97         ):
  98             last_dt = dt
  99             try:
 100                 dt = parser.parse(day.get_text())
 101             except Exception:
 102                 dt = last_dt
 103             assert dt is not None
 104
 105             # Compute sunrise/sunset times on dt.
 106             city = astral.LocationInfo(
 107                 "Bellevue", "USA", "US/Pacific", 47.653, -122.171
 108             )
 109             s = sun(city.observer, date=dt, tzinfo=pytz.timezone("US/Pacific"))
 110             sunrise = s['sunrise']
 111             sunset = s['sunset']
 112
 113             if dt.date() == now.date() and not said_temp and current_temp is not None:
 114                 blurb = f'{day.get_text()}: The current outside tempterature is {current_temp}. '
 115                 blurb += txt.get_text()
 116                 said_temp = True
 117             else:
 118                 blurb = f'{day.get_text()}: {txt.get_text()}'
 119             blurb = text_utils.wrap_string(blurb, 80)
 120
 121             if dt.date() in self.forecasts:
 122                 self.forecasts[dt.date()].description += '\n' + blurb
 123             else:
 124                 self.forecasts[dt.date()] = WeatherForecast(
 125                     date = dt,
 126                     sunrise = sunrise,
 127                     sunset = sunset,
 128                     description = blurb,
 129                 )
 130
 131     @classmethod
 132     def load(cls):
 133         if persistent.was_file_written_within_n_seconds(
 134                 config.config['weather_forecast_cachefile'],
 135                 config.config['weather_forecast_stalest_acceptable'].total_seconds(),
 136         ):
 137             import pickle
 138             with open(config.config['weather_forecast_cachefile'], 'rb') as rf:
 139                 weather_data = pickle.load(rf)
 140                 return cls(weather_data)
 141         return None
 142
 143     def save(self):
 144         import pickle
 145         with open(config.config['weather_forecast_cachefile'], 'wb') as wf:
 146             pickle.dump(
 147                 self.forecasts,
 148                 wf,
 149                 pickle.HIGHEST_PROTOCOL,
 150             )