def _get_distance(self):
from haystack.utils.geo import Distance
if self._distance is None:
# We didn't get it from the backend & we haven't tried calculating
# it yet. Check if geopy is available to do it the "slow" way
# (even though slow meant 100 distance calculations in 0.004 seconds
# in my testing).
if geopy_distance is None:
raise SpatialError("The backend doesn't have 'DISTANCE_AVAILABLE' enabled & the 'geopy' library could not be imported, so distance information is not available.")
if not self._point_of_origin:
raise SpatialError("The original point is not available.")
if not hasattr(self, self._point_of_origin['field']):
raise SpatialError("The field '%s' was not included in search results, so the distance could not be calculated." % self._point_of_origin['field'])
po_lng, po_lat = self._point_of_origin['point'].get_coords()
location_field = getattr(self, self._point_of_origin['field'])
if location_field is None:
return None
lf_lng, lf_lat = location_field.get_coords()
self._distance = Distance(km=geopy_distance.distance((po_lat, po_lng), (lf_lat, lf_lng)).km)
# We've either already calculated it or the backend returned it, so
# let's use that.
return self._distance
def ensure_geometry(geom):
"""
Makes sure the parameter passed in looks like a GEOS ``GEOSGeometry``.
"""
if not hasattr(geom, 'geom_type'):
raise SpatialError("Point '%s' doesn't appear to be a GEOS geometry." % geom)
return geom
def ensure_polygon(geom):
"""
Makes sure the parameter passed in looks like a GEOS ``Polygon``.
"""
ensure_geometry(geom)
if geom.geom_type != 'Polygon':
raise SpatialError("Provided geometry '%s' is not a 'Polygon'." % geom)
return geom
def ensure_multipoint(geom):
"""
Makes sure the parameter passed in looks like a GEOS ``MultiPoint``.
"""
ensure_geometry(geom)
if geom.geom_type != 'MultiPoint':
raise SpatialError("Provided geometry '%s' is not a 'MultiPoint'." % geom)
return geom
def ensure_distance(dist):
"""
Makes sure the parameter passed in is a 'Distance' object.
"""
try:
# Since we mostly only care about the ``.km`` attribute, make sure
# it's there.
km = dist.km
except AttributeError:
raise SpatialError("'%s' does not appear to be a 'Distance' object." % dist)
return dist
def ensure_relation(relation):
if relation not in VALID_RELATIONS:
raise SpatialError("'{}' must be one of {}".format(
relation, VALID_RELATIONS))
return relation
