weather.py

import os
import logging
import json
import time
from collections import namedtuple

import requests


Weather = namedtuple( 'Weather', ['temp','temp_min','temp_max','icon'] )


def cache_path():
    pth_cache = os.path.expanduser( "~/.clock/cache/" )
    if not os.path.exists( pth_cache ):
        os.makedirs( pth_cache )
    return os.path.join( pth_cache, "darksky.json" )


def load_cached():
    
    cached = None
    
    fn_cache = cache_path()
    
    if os.path.exists(fn_cache):
        
        logging.info( "load cache file: %s" % fn_cache )
        with open(fn_cache) as fp:
            return json.load(fp)

    return None


def get_cache_ts():
    fn_cache = cache_path()
    if os.path.exists(fn_cache):
        return os.path.getmtime(fn_cache)
    return None


def fetch_forecast():

    logging.info( "Get a fresh forecast from the internet...")
    
    try:
        r = requests.get(
            "https://api.darksky.net/forecast/{}/{}".format(
                os.environ.get( "DARKSKY_KEY" ),
                os.environ.get( "LAT_LON" )
            ),
            params = {
                "units" : "si",
                "exclude" : "minutely,hourly,alerts,flags"
            }
        )
        
        # write forecast data to cache
        fn_cache = cache_path()
        with open(fn_cache,'wb') as fp:
            fp.write( r.text.encode('utf-8') )

        return r.json()
    
    except Exception as e:
        logging.exception( e )

    return None


def load_forecast():
    
    # start from cached data 
    forecast_data = load_cached()

    # no forecast has been cached yet
    if forecast_data is None:
        forecast_data = fetch_forecast()

    else:
        # get last modified time for cache...
        ts_cache = get_cache_ts()
        
        # refresh every 10 minutes
        if ts_cache is not None:
            now = time.time()
            if (now - ts_cache) > (60*10):
                forecast_data = fetch_forecast()        

    return forecast_data


def get_weather():

    forecast_data = load_forecast()        
    
    d = forecast_data["daily"]["data"][0]

    temp_min = d["temperatureMin"]
    temp_max = d["temperatureMax"]

    c = forecast_data['currently']

    return Weather(
        temp=c['temperature'],
        temp_min=temp_min,
        temp_max=temp_max,
        icon=d['icon']
    )

if __name__ == '__main__':
    print( get_weather() )