lib/geokit-rails/acts_as_mappable/class_methods.rb
module Geokit
module ActsAsMappable
# Class methods included in models when +acts_as_mappable+ is called
module ClassMethods
# A proxy to an instance of a finder adapter, inferred from the connection's adapter.
def geokit_finder_adapter
@geokit_finder_adapter ||= begin
unless Adapters.const_defined?(connection.adapter_name.camelcase)
filename = connection.adapter_name.downcase
require File.join("geokit-rails", "adapters", filename)
end
klass = Adapters.const_get(connection.adapter_name.camelcase)
if klass.class == Module
# For some reason Mysql2 adapter was defined in Adapters.constants but was Module instead of a Class
filename = connection.adapter_name.downcase
require File.join("geokit-rails", "adapters", filename)
# Re-init the klass after require
klass = Adapters.const_get(connection.adapter_name.camelcase)
end
klass.load(self) unless klass.loaded || skip_loading
klass.new(self)
rescue LoadError
raise UnsupportedAdapter, "`#{connection.adapter_name.downcase}` is not a supported adapter."
end
end
def within(distance, options = {})
options[:within] = distance
# Add bounding box to speed up SQL request.
bounds = formulate_bounds_from_distance(
options,
normalize_point_to_lat_lng(options[:origin]),
options[:units] || default_units)
with_latlng.where(bound_conditions(bounds)).
where(distance_conditions(options))
end
alias inside within
def beyond(distance, options = {})
options[:beyond] = distance
#geo_scope(options)
where(distance_conditions(options))
end
alias outside beyond
def in_range(range, options = {})
options[:range] = range
#geo_scope(options)
where(distance_conditions(options))
end
def in_bounds(bounds, options = {})
inclusive = options.delete(:inclusive) || false
options[:bounds] = bounds
#geo_scope(options)
#where(distance_conditions(options))
bounds = extract_bounds_from_options(options)
where(bound_conditions(bounds, inclusive))
end
def by_distance(options = {})
origin = extract_origin_from_options(options)
units = extract_units_from_options(options)
formula = extract_formula_from_options(options)
distance_column_name = distance_sql(origin, units, formula)
with_latlng.order(
Arel.sql(distance_column_name).send(options[:reverse] ? 'desc' : 'asc')
)
end
def with_latlng
where(arel_table[lat_column_name].not_eq(nil).and(arel_table[lng_column_name].not_eq(nil)))
end
def closest(options = {})
by_distance(options).limit(1)
end
alias nearest closest
def farthest(options = {})
by_distance({:reverse => true}.merge(options)).limit(1)
end
#def geo_scope(options = {})
# arel = self.is_a?(ActiveRecord::Relation) ? self : self.scoped
# origin = extract_origin_from_options(options)
# units = extract_units_from_options(options)
# formula = extract_formula_from_options(options)
# bounds = extract_bounds_from_options(options)
# if origin || bounds
# bounds = formulate_bounds_from_distance(options, origin, units) unless bounds
# if origin
# arel.distance_formula = distance_sql(origin, units, formula)
#
# if arel.select_values.blank?
# star_select = Arel::Nodes::SqlLiteral.new(arel.quoted_table_name + '.*')
# arel = arel.select(star_select)
# end
# end
# if bounds
# bound_conditions = bound_conditions(bounds)
# arel = arel.where(bound_conditions) if bound_conditions
# end
# distance_conditions = distance_conditions(options)
# arel = arel.where(distance_conditions) if distance_conditions
# if self.through
# arel = arel.includes(self.through)
# end
# end
# arel
#end
# Returns the distance calculation to be used as a display column or a condition. This
# is provide for anyone wanting access to the raw SQL.
def distance_sql(origin, units=default_units, formula=default_formula)
case formula
when :sphere
sql = sphere_distance_sql(origin, units)
when :flat
sql = flat_distance_sql(origin, units)
end
sql
end
private
# Override ActiveRecord::Base.relation to return an instance of Geokit::ActsAsMappable::Relation.
# TODO: Do we need to override JoinDependency#relation too?
#def relation
# # NOTE: This cannot be @relation as ActiveRecord already uses this to
# # cache *its* Relation object
# @_geokit_relation ||= Relation.new(self, arel_table)
# finder_needs_type_condition? ? @_geokit_relation.where(type_condition) : @_geokit_relation
#end
# If it's a :within query, add a bounding box to improve performance.
# This only gets called if a :bounds argument is not otherwise supplied.
def formulate_bounds_from_distance(options, origin, units)
distance = options[:within] if options.has_key?(:within) && options[:within].is_a?(Numeric)
distance = options[:range].last-(options[:range].exclude_end?? 1 : 0) if options.has_key?(:range)
if distance
Geokit::Bounds.from_point_and_radius(origin,distance,:units=>units)
else
nil
end
end
def distance_conditions(options)
origin = extract_origin_from_options(options)
units = extract_units_from_options(options)
formula = extract_formula_from_options(options)
distance_column_name = distance_sql(origin, units, formula)
if options.has_key?(:within)
Arel.sql(distance_column_name).lteq(options[:within])
elsif options.has_key?(:beyond)
Arel.sql(distance_column_name).gt(options[:beyond])
elsif options.has_key?(:range)
min_condition = Arel.sql(distance_column_name).gteq(options[:range].begin)
max_condition = if options[:range].exclude_end?
Arel.sql(distance_column_name).lt(options[:range].end)
else
Arel.sql(distance_column_name).lteq(options[:range].end)
end
min_condition.and(max_condition)
end
end
def bound_conditions(bounds, inclusive = false)
return nil unless bounds
if inclusive
lt_operator = :lteq
gt_operator = :gteq
else
lt_operator = :lt
gt_operator = :gt
end
sw,ne = bounds.sw, bounds.ne
lat, lng = Arel.sql(qualified_lat_column_name), Arel.sql(qualified_lng_column_name)
lat.send(gt_operator, sw.lat).and(lat.send(lt_operator, ne.lat)).and(
if bounds.crosses_meridian?
lng.send(lt_operator, ne.lng).or(lng.send(gt_operator, sw.lng))
else
lng.send(gt_operator, sw.lng).and(lng.send(lt_operator, ne.lng))
end
)
end
# Extracts the origin instance out of the options if it exists and returns
# it. If there is no origin, looks for latitude and longitude values to
# create an origin. The side-effect of the method is to remove these
# option keys from the hash.
def extract_origin_from_options(options)
origin = options.delete(:origin)
res = normalize_point_to_lat_lng(origin) if origin
res
end
# Extract the units out of the options if it exists and returns it. If
# there is no :units key, it uses the default. The side effect of the
# method is to remove the :units key from the options hash.
def extract_units_from_options(options)
units = options[:units] || default_units
options.delete(:units)
units
end
# Extract the formula out of the options if it exists and returns it. If
# there is no :formula key, it uses the default. The side effect of the
# method is to remove the :formula key from the options hash.
def extract_formula_from_options(options)
formula = options[:formula] || default_formula
options.delete(:formula)
formula
end
def extract_bounds_from_options(options)
bounds = options.delete(:bounds)
bounds = Geokit::Bounds.normalize(bounds) if bounds
end
# Geocode IP address.
def geocode_ip_address(origin)
geo_location = Geokit::Geocoders::MultiGeocoder.geocode(origin)
return geo_location if geo_location.success
raise Geokit::Geocoders::GeocodeError
end
# Given a point in a variety of (an address to geocode,
# an array of [lat,lng], or an object with appropriate lat/lng methods, an IP addres)
# this method will normalize it into a Geokit::LatLng instance. The only thing this
# method adds on top of LatLng#normalize is handling of IP addresses
def normalize_point_to_lat_lng(point)
res = geocode_ip_address(point) if point.is_a?(String) && /^(\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3})?$/.match(point)
res = Geokit::LatLng.normalize(point) unless res
res
end
# Looks for the distance column and replaces it with the distance sql. If an origin was not
# passed in and the distance column exists, we leave it to be flagged as bad SQL by the database.
# Conditions are either a string or an array. In the case of an array, the first entry contains
# the condition.
def substitute_distance_in_where_values(arel, origin, units=default_units, formula=default_formula)
pattern = Regexp.new("\\b#{distance_column_name}\\b")
value = distance_sql(origin, units, formula)
arel.where_values.map! do |where_value|
if where_value.is_a?(String)
where_value.gsub(pattern, value)
else
where_value
end
end
arel
end
# Returns the distance SQL using the spherical world formula (Haversine). The SQL is tuned
# to the database in use.
def sphere_distance_sql(origin, units)
# "origin" can be a Geokit::LatLng (with :lat and :lng methods), e.g.
# when using geo_scope or it can be an ActsAsMappable with customized
# latitude and longitude methods, e.g. when using distance_sql.
lat = deg2rad(get_lat(origin))
lng = deg2rad(get_lng(origin))
multiplier = units_sphere_multiplier(units)
geokit_finder_adapter.sphere_distance_sql(lat, lng, multiplier) if geokit_finder_adapter
end
# Returns the distance SQL using the flat-world formula (Phythagorean Theory). The SQL is tuned
# to the database in use.
def flat_distance_sql(origin, units)
lat_degree_units = units_per_latitude_degree(units)
lng_degree_units = units_per_longitude_degree(get_lat(origin), units)
geokit_finder_adapter.flat_distance_sql(origin, lat_degree_units, lng_degree_units)
end
def get_lat(origin)
origin.respond_to?(:lat) ? origin.lat \
: origin.send(:"#{lat_column_name}")
end
def get_lng(origin)
origin.respond_to?(:lng) ? origin.lng \
: origin.send(:"#{lng_column_name}")
end
end # ClassMethods
end
end