teeminus10_helpers.py

import ephem
import logging
import json
import requests
import requests_cache
import threading
import unittest
from calendar import timegm
from datetime import datetime, timedelta
from math import degrees

logger = logging.getLogger('teeminus10')

API_URLS = { 'iss': "http://api.open-notify.org/iss/?lat={0}&lon={1}&alt={2}&n={3}",
             'weather': {'city_now': "http://api.openweathermap.org/data/2.5/weather?q={0}",
                         'coord_now': "http://api.openweathermap.org/data/2.5/weather?lat={0}&lon={1}",
                         'city_forecast': "http://api.openweathermap.org/data/2.5/forecast?q={0}",
                         'city_search': "http://api.openweathermap.org/data/2.5/find?q={0}&mode=json"
                     },
             'timezone': "http://api.geonames.org/timezoneJSON?username={0}&lat={1}&lng={2}"
         }

ACS_URLS = { 'notify': "https://api.cloud.appcelerator.com/v1/push_notification/notify.json?key={0}",
             'login': "https://api.cloud.appcelerator.com/v1/users/login.json?key={0}",
             'subscribe': "https://api.cloud.appcelerator.com/v1/push_notifications/subscribe.json?key={0}"
         }

TIMERS = {}

def in_time_of_day(observer, pass_time, time_of_day):
    '''Returns sunset and sunrise times for the given Observer at date'''
    location = ephem.Observer()
    location.lat = observer.lat
    location.long = observer.long
    location.date = pass_time
    sun = ephem.Sun()
    if time_of_day == "day":
        previous_rising = location.previous_rising(sun).datetime()
        next_setting = location.next_setting(sun, start=pass_time.date()).datetime()
        return previous_rising.date() == pass_time.date() and pass_time <= next_setting
    elif time_of_day == "night":
        previous_rising = location.previous_rising(sun).datetime()
        previous_setting = location.previous_setting(sun).datetime()
        next_rising = location.next_rising(sun).datetime()
        return (previous_setting.date() == pass_time.date() and pass_time <= next_rising) or (next_rising.date() == pass_time.date() and pass_time <= next_rising)
    else:
        return True

def get_latlong_from_city(city):
    tokens = [t.strip() for t in city.split(',')]
    url = API_URLS['weather']['city_search'].format(tokens[0])
    r = requests.get(url)
    data = json.loads(r.text)
    for city in data['list']:
        country_code = city['sys']['country']
        if len(tokens) > 1 and country_code == tokens[1]:
            return {'lat': city['coord']['lat'] * ephem.degree,
                    'long': city['coord']['lon'] * ephem.degree,
                    'city': city['name'],
                    'country_code': country_code}
    # If we got here, we don't know. Just return the first result
    city = data['list'][0]
    country_code = city['sys']['country']
    return {'lat': city['coord']['lat'] * ephem.degree,
            'long': city['coord']['lon'] * ephem.degree,
            'city': city['name'],
            'country_code': country_code}

class WeatherData():
    def __init__(self, city):
        self.city = city

    def __do_get(self, url):
        with requests_cache.disabled():
            r = requests.get(url)
            logger.info("Request of weather data to {0}.".format(url))
            try:
                return json.loads(r.text)
            except ValueError:
                logger.warning("Could not get weather data from {0}".format(url))
                return {} # Something went wrong!

    def current_cloud_cover(self):
        url = API_URLS['weather']['city_now'].format(self.city)
        data = self.__do_get(url)
        return data['clouds']['all'] / 100.0

    def cloud_forecast(self, date):
        url = API_URLS['weather']['city_forecast'].format(self.city)
        data = self.__do_get(url)
        forecast = data['list']
        least_diff = 9999999999999
        closest_forecast = None
        for f in forecast:
            time_diff = (date - datetime.utcfromtimestamp(f['dt'])).total_seconds()
            if abs(time_diff) < least_diff:
                least_diff = time_diff
                closest_forecast = f
        return closest_forecast['clouds']['all'] / 100.0

class T10Helper():
    '''"Server" for handling alerts, checking weather, what not.'''
    def __init__(self, acs, tz):
        self.acs = acs
        self.tz = tz
        # Install sqlite cache for celestrak with a 24 hour duration
        # Good enough for celestrak and other data. Cache disabled when appropriate
        requests_cache.install_cache('teeminus10_cache', expire_after=24*60*60)
        requests_cache.clear()

    def __get_iss_data(self):
        r = requests.get("http://celestrak.com/NORAD/elements/stations.txt")
        tle_data = r.text
        logger.info("Requested celestrak data. Cached: {0}".format(r.from_cache))
        iss_tle = [str(l).strip() for l in tle_data.split('\r\n')[:3]]

        return ephem.readtle(*iss_tle)

    def get_cloud_cover(self, city):
        '''Gets cloud cover in % for the given city'''
        url = API_URLS['weather']['city_search'].format(city)
        logger.info("Requesting cloud cover for {0}.".format(city))
        with requests_cache.disabled():
            r = requests.get(url)
            try:
                result = json.loads(r.text)
            except ValueError:
                logger.warning("Could not get cloud cover for {0}".format(city))
                return '0'
            return result['data']['current_condition'][0]['cloudcover']


    def get_next_passes(self, lat, lon, altitude, count, force_visible=False, time_of_day="either"):
        '''Returns a list of the next visible passes for the ISS'''

        iss = self.__get_iss_data()

        location = ephem.Observer()
        location.lat = str(lat)
        location.long = str(lon)
        location.elevation = altitude

        # Ignore effects of atmospheric refraction
        location.pressure = 0
        location.horizon = '5:00'

        location.date = datetime.utcnow()
        passes = []
        now_plus_ten_days = datetime.utcnow() + timedelta(days=10)
        iss.compute(location)
        while len(passes) < count and location.date.datetime() < now_plus_ten_days:
            tr, azr, tt, altt, ts, azs = location.next_pass(iss)
            # Skip if the pass is at the wrong time of day
            if in_time_of_day(location, datetime.utcfromtimestamp(tr), time_of_day):
                duration = int((ts - tr) * 60 * 60 * 24)
                year, month, day, hour, minute, second = tr.tuple()
                dt = datetime(year, month, day, hour, minute, int(second))
                if not (force_visible and iss.eclipsed):
                    passes.append({"risetime": timegm(dt.timetuple()), "duration": duration, "azimuth": ephem.degrees(azr), "altitude": ephem.degrees(altt)})
            location.date = tr
            iss.compute(location)
            location.date = tr + 25 * ephem.minute

        return {"response": passes }

    def get_current_iss_location(self):
        '''Returns the current ISS location'''
        iss = self.__get_iss_data()

        now = datetime.utcnow()
        iss.compute(now)
        lon = degrees(iss.sublong)
        lat = degrees(iss.sublat)

        return {'response': {'latitude': lat, 'longitude': lon}}

    def alert_next_passes(self, acc_cloud_cover, timeofday, device_id, count=10, city="", coord=(0.0, 0.0)):
        '''Sets up alerts for up to the next 10 passes of the ISS over the given city or lat/lon.
        Alerts will be sent to the device that registered for them'''
        location = ephem.Observer()
        city_name = city
        country = ""
        if city is not "":
            data = get_latlong_from_city(city)
            city_name = data['city']
            country = data['country_code']
            location.lat = data['lat']
            location.long = data['long']
        else:
            location.lat = coord[0]
            location.long = coord[1]
        try:
            # Cancel previous timers.
            for t in TIMERS[city]:
                t.cancel()
        except KeyError:
            pass
        finally:
            TIMERS[city] = []
        result = self.get_next_passes(degrees(location.lat), degrees(location.lon), int(location.elevation), count, time_of_day=timeofday)
        tzinfo = self.tz.get_timezone(degrees(location.lat), degrees(location.lon))
        next_passes = result['response']
        # For every pass, set up a trigger for 10 minutes earlier and send it
        # to the 'space' channel
        real_response = []
        for p in next_passes:
            risetime = datetime.utcfromtimestamp(p['risetime'])
            weather_data = WeatherData(city)
            riseminus15 = risetime - timedelta(minutes=15)
            delay = (riseminus15 - datetime.utcnow()).total_seconds()
            logger.debug("Running in {0} seconds...".format(delay))
            def f():
                weather_data = WeatherData(city)
                cloud_cover = weather_data.current_cloud_cover()
                alert_time = datetime.utcnow() + timedelta(minutes=5)
                if cloud_cover <= acc_cloud_cover:
                    logger.debug("Cloud cover acceptable for {0}".format(city))
                    self.acs.push_to_ids_at_channel('space', [device_id], json.dumps({'location': city,
                                                                                      'alert_time': alert_time,
                                                                                      'cloudcover': cloud_cover}))
            t = threading.Timer(delay, f)
            TIMERS[city].append(t)
            t.start()
            cloud_forecast = weather_data.cloud_forecast(datetime.utcfromtimestamp(p['risetime']))
            real_response.append({'location': dict({'city': city_name,
                                                    'country': country,
                                                }.items() + tzinfo.items()),
                                  'duration': p['duration'],
                                  'time_str': str(risetime),
                                  'time': p['risetime'],
                                  'cloudcover': cloud_forecast,
                                  'trigger_time': str(riseminus15),
                              })
        return real_response

    def delete_alerts(self, city):
        try:
            # Cancel previous timers.
            for t in TIMERS[city]:
                t.cancel()
        except KeyError:
            pass
        finally:
            TIMERS[city] = []

class T10TZHelper():
    '''Gets timezone information'''
    def __init__(self, username):
        self.user = username

    def get_timezone(self, lat, lon):
        url = API_URLS['timezone'].format(self.user, lat, lon)
        r = requests.get(url)
        logger.info("Requested timezone data. Cached: {0}".format(r.from_cache))
        data = json.loads(r.text)
        try:
            return {'utc_offset': data['rawOffset'], 'timezone': data['timezoneId']}
        except KeyError:
            logger.info("Got no timezone data for {0} {1}".format(lat, lon))
            return {}

class T10ACSHelper():
    '''Handles connections to Appcelerator Cloud Services and does push notifications'''
    def __init__(self, user, password, key):
        self.key = key
        self.user = user
        self.password = password
        self.__login()
        self.clients = {}

    def __login(self):
        '''Need to login to appcelerator'''
        payload = {'login':self.user, 'password':self.password}

        with requests_cache.disabled():
            r = requests.post(ACS_URLS['login'].format(self.key), data=payload)
            self.cookies = r.cookies

    def subscribe_device(self, channel, device_type, device_id):
        try:
            self.clients[channel].append(device_id)
        except KeyError:
            self.clients[channel] = [device_id]
        finally:
            url = ACS_URLS['subscribe'].format(self.key)
            payload = {'type':device_type, 'device_id':device_id, 'channel':'channel'}
            with requests_cache.disabled():
                r = requests.post(url, data=payload, cookies=self.cookies)

    def push_to_channel(self, channel, message):
        try:
            self.push_to_ids_at_channel(channel, self.clients[channel], message)
        except KeyError:
            return

    def push_to_ids_at_channel(self, channel, ids, message):
        logger.debug("Pushing {0} to {1}".format(message, channel))
        string_ids = ",".join(ids)
        payload = {'channel':channel, 'to_ids':string_ids, 'payload':json.dumps({'badge':2, 'sound':'default', 'alert':message})}
        url = ACS_URLS['notify'].format(self.key)
        with requests_cache.disabled():
            r = requests.post(url, data=payload, cookies=self.cookies)