class DistanceCalculator(object):
_geoip4 = None
_geoip6 = None
def __init__(self):
# Load the GeoIP databases into class attributes since they each need 20+ MB in memory
if not self.__class__._geoip4:
self.__class__._geoip4 = GeoIP(Config.GEOIP_PATH_V4, MEMORY_CACHE)
if not self.__class__._geoip6:
self.__class__._geoip6 = GeoIP(Config.GEOIP_PATH_V6, MEMORY_CACHE)
self.redis = StrictRedis(Config.REDIS['HOST'], Config.REDIS['PORT'],
Config.REDIS['DB'])
@staticmethod
def _haversine(lon1, lat1, lon2, lat2):
"""
Calculate the great circle distance between two points
on the earth (specified in decimal degrees)
"""
# convert decimal degrees to radians
lon1, lat1, lon2, lat2 = map(lambda v: radians(float(v)),
[lon1, lat1, lon2, lat2])
# haversine formula
dlon = lon2 - lon1
dlat = lat2 - lat1
a = sin(dlat / 2)**2 + cos(lat1) * cos(lat2) * sin(dlon / 2)**2
c = 2 * asin(sqrt(a))
km = 6367 * c # convert to km
return km
def get_mirror_distances(self, address):
last_update = self.redis.get(Config.KEY_LAST_UPDATE)
key = Config.KEY_MIRROR.format(address, last_update)
distances = OrderedDict(self.redis.zrange(key, 0, -1, withscores=True))
if not distances:
if address.startswith("::ffff:"):
address = address.replace("::ffff:", "")
try:
if ":" in address:
record = self._geoip6.record_by_addr(address)
else:
record = self._geoip4.record_by_addr(address)
except socket.error:
raise GeoIPLookupError()
if not record:
raise GeoIPLookupError()
lat = record['latitude']
lon = record['longitude']
distances = OrderedDict(
sorted(((mirror.name,
self._haversine(lon, lat, mirror.lon, mirror.lat))
for mirror in Mirror.objects.filter(age__lt=3601)),
key=itemgetter(1)))
if distances:
self.redis.zadd(key, **distances)
self.redis.expire(key, 60 * 10) # 10 min
return distances
def get_nearest_mirror(self, address):
try:
distances = self.get_mirror_distances(address)
if distances:
return next(distances.iteritems())[0]
return Config.FALLBACK_MIRROR
except GeoIPLookupError:
return Config.FALLBACK_MIRROR
class DistanceCalculator(object):
_geoip4 = None
_geoip6 = None
def __init__(self):
# Load the GeoIP databases into class attributes since they each need 20+ MB in memory
if not self.__class__._geoip4:
self.__class__._geoip4 = GeoIP(Config.GEOIP_PATH_V4, MEMORY_CACHE)
if not self.__class__._geoip6:
self.__class__._geoip6 = GeoIP(Config.GEOIP_PATH_V6, MEMORY_CACHE)
self.redis = StrictRedis(Config.REDIS['HOST'], Config.REDIS['PORT'], Config.REDIS['DB'])
@staticmethod
def _haversine(lon1, lat1, lon2, lat2):
"""
Calculate the great circle distance between two points
on the earth (specified in decimal degrees)
"""
# convert decimal degrees to radians
lon1, lat1, lon2, lat2 = map(lambda v: radians(float(v)), [lon1, lat1, lon2, lat2])
# haversine formula
dlon = lon2 - lon1
dlat = lat2 - lat1
a = sin(dlat / 2) ** 2 + cos(lat1) * cos(lat2) * sin(dlon / 2) ** 2
c = 2 * asin(sqrt(a))
km = 6367 * c # convert to km
return km
def get_mirror_distances(self, address):
last_update = self.redis.get(Config.KEY_LAST_UPDATE)
key = Config.KEY_MIRROR.format(address, last_update)
distances = OrderedDict(self.redis.zrange(key, 0, -1, withscores=True))
if not distances:
if address.startswith("::ffff:"):
address = address.replace("::ffff:", "")
try:
if ":" in address:
record = self._geoip6.record_by_addr(address)
else:
record = self._geoip4.record_by_addr(address)
except socket.error:
raise GeoIPLookupError()
if not record:
raise GeoIPLookupError()
lat = record['latitude']
lon = record['longitude']
distances = OrderedDict(
sorted(
(
(mirror.name, self._haversine(lon, lat, mirror.lon, mirror.lat))
for mirror in Mirror.objects.filter(age__lt=3601)
),
key=itemgetter(1)
)
)
if distances:
self.redis.zadd(key, **distances)
self.redis.expire(key, 60 * 10) # 10 min
return distances
def get_nearest_mirror(self, address):
try:
distances = self.get_mirror_distances(address)
if distances:
return next(distances.iteritems())[0]
return Config.FALLBACK_MIRROR
except GeoIPLookupError:
return Config.FALLBACK_MIRROR
