X-Git-Url: https://projects.mako.cc/source/selectricity-live/blobdiff_plain/baf9ff0ec39c13f52ee8d4f087641dc5fcc9c53b..fcc68b4dc198b7cb0cf93467d96038b0844675fe:/vendor/plugins/geokit/lib/geo_kit/acts_as_mappable.rb

diff --git a/vendor/plugins/geokit/lib/geo_kit/acts_as_mappable.rb b/vendor/plugins/geokit/lib/geo_kit/acts_as_mappable.rb
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+module GeoKit
+  # Contains the class method acts_as_mappable targeted to be mixed into ActiveRecord.
+  # When mixed in, augments find services such that they provide distance calculation
+  # query services.  The find method accepts additional options:
+  #
+  # * :origin - can be 
+  #   1. a two-element array of latititude/longitude -- :origin=>[37.792,-122.393]
+  #   2. a geocodeable string -- :origin=>'100 Spear st, San Francisco, CA'
+  #   3. an object which responds to lat and lng methods, or latitude and longitude methods,
+  #      or whatever methods you have specified for lng_column_name and lat_column_name
+  #
+  # Other finder methods are provided for specific queries.  These are:
+  #
+  # * find_within (alias: find_inside)
+  # * find_beyond (alias: find_outside)
+  # * find_closest (alias: find_nearest)
+  # * find_farthest
+  #
+  # Counter methods are available and work similarly to finders.  
+  #
+  # If raw SQL is desired, the distance_sql method can be used to obtain SQL appropriate
+  # to use in a find_by_sql call.
+  module ActsAsMappable 
+    # Mix below class methods into ActiveRecord.
+    def self.included(base) # :nodoc:
+      base.extend ClassMethods
+    end
+    
+    # Class method to mix into active record.
+    module ClassMethods # :nodoc:
+      # Class method to bring distance query support into ActiveRecord models.  By default
+      # uses :miles for distance units and performs calculations based upon the Haversine
+      # (sphere) formula.  These can be changed by setting GeoKit::default_units and
+      # GeoKit::default_formula.  Also, by default, uses lat, lng, and distance for respective
+      # column names.  All of these can be overridden using the :default_units, :default_formula,
+      # :lat_column_name, :lng_column_name, and :distance_column_name hash keys.
+      # 
+      # Can also use to auto-geocode a specific column on create. Syntax;
+      #   
+      #   acts_as_mappable :auto_geocode=>true
+      # 
+      # By default, it tries to geocode the "address" field. Or, for more customized behavior:
+      #   
+      #   acts_as_mappable :auto_geocode=>{:field=>:address,:error_message=>'bad address'}
+      #   
+      # In both cases, it creates a before_validation_on_create callback to geocode the given column.
+      # For anything more customized, we recommend you forgo the auto_geocode option
+      # and create your own AR callback to handle geocoding.
+      def acts_as_mappable(options = {})
+        # Mix in the module, but ensure to do so just once.
+        return if self.included_modules.include?(GeoKit::ActsAsMappable::InstanceMethods)
+        send :include, GeoKit::ActsAsMappable::InstanceMethods
+        # include the Mappable module.
+        send :include, Mappable
+        
+        # Handle class variables.
+        cattr_accessor :distance_column_name, :default_units, :default_formula, :lat_column_name, :lng_column_name, :qualified_lat_column_name, :qualified_lng_column_name
+        self.distance_column_name = options[:distance_column_name]  || 'distance'
+        self.default_units = options[:default_units] || GeoKit::default_units
+        self.default_formula = options[:default_formula] || GeoKit::default_formula
+        self.lat_column_name = options[:lat_column_name] || 'lat'
+        self.lng_column_name = options[:lng_column_name] || 'lng'
+        self.qualified_lat_column_name = "#{table_name}.#{lat_column_name}"
+        self.qualified_lng_column_name = "#{table_name}.#{lng_column_name}"
+        if options.include?(:auto_geocode) && options[:auto_geocode]
+          # if the form auto_geocode=>true is used, let the defaults take over by suppling an empty hash
+          options[:auto_geocode] = {} if options[:auto_geocode] == true 
+          cattr_accessor :auto_geocode_field, :auto_geocode_error_message
+          self.auto_geocode_field = options[:auto_geocode][:field] || 'address'
+          self.auto_geocode_error_message = options[:auto_geocode][:error_message] || 'could not locate address'
+          
+          # set the actual callback here
+          before_validation_on_create :auto_geocode_address        
+        end
+      end
+    end
+    
+    # this is the callback for auto_geocoding
+    def auto_geocode_address
+      address=self.send(auto_geocode_field)
+      geo=GeoKit::Geocoders::MultiGeocoder.geocode(address)
+  
+      if geo.success
+        self.send("#{lat_column_name}=", geo.lat)
+        self.send("#{lng_column_name}=", geo.lng)
+      else
+        errors.add(auto_geocode_field, auto_geocode_error_message) 
+      end
+      
+      geo.success
+    end
+    
+    # Instance methods to mix into ActiveRecord.
+    module InstanceMethods #:nodoc:    
+      # Mix class methods into module.
+      def self.included(base) # :nodoc:
+        base.extend SingletonMethods
+      end
+      
+      # Class singleton methods to mix into ActiveRecord.
+      module SingletonMethods # :nodoc:
+        # Extends the existing find method in potentially two ways:
+        # - If a mappable instance exists in the options, adds a distance column.
+        # - If a mappable instance exists in the options and the distance column exists in the
+        #   conditions, substitutes the distance sql for the distance column -- this saves
+        #   having to write the gory SQL.
+        def find(*args)
+          prepare_for_find_or_count(:find, args)
+          super(*args)
+        end     
+        
+        # Extends the existing count method by:
+        # - If a mappable instance exists in the options and the distance column exists in the
+        #   conditions, substitutes the distance sql for the distance column -- this saves
+        #   having to write the gory SQL.
+        def count(*args)
+          prepare_for_find_or_count(:count, args)
+          super(*args)
+        end
+        
+        # Finds within a distance radius.
+        def find_within(distance, options={})
+          options[:within] = distance
+          find(:all, options)
+        end
+        alias find_inside find_within
+                
+        # Finds beyond a distance radius.
+        def find_beyond(distance, options={})
+          options[:beyond] = distance
+          find(:all, options)
+        end
+        alias find_outside find_beyond
+        
+        # Finds according to a range.  Accepts inclusive or exclusive ranges.
+        def find_by_range(range, options={})
+          options[:range] = range
+          find(:all, options)
+        end
+        
+        # Finds the closest to the origin.
+        def find_closest(options={})
+          find(:nearest, options)
+        end
+        alias find_nearest find_closest
+        
+        # Finds the farthest from the origin.
+        def find_farthest(options={})
+          find(:farthest, options)
+        end
+
+        # Finds within rectangular bounds (sw,ne).
+        def find_within_bounds(bounds, options={})
+          options[:bounds] = bounds
+          find(:all, options)
+        end
+        
+        # counts within a distance radius.
+        def count_within(distance, options={})
+          options[:within] = distance
+          count(options)
+        end
+        alias count_inside count_within
+
+        # Counts beyond a distance radius.
+        def count_beyond(distance, options={})
+          options[:beyond] = distance
+          count(options)
+        end
+        alias count_outside count_beyond
+        
+        # Counts according to a range.  Accepts inclusive or exclusive ranges.
+        def count_by_range(range, options={})
+          options[:range] = range
+          count(options)
+        end
+
+        # Finds within rectangular bounds (sw,ne).
+        def count_within_bounds(bounds, options={})
+          options[:bounds] = bounds
+          count(options)
+        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
+        
+        # Prepares either a find or a count action by parsing through the options and
+        # conditionally adding to the select clause for finders.
+        def prepare_for_find_or_count(action, args)
+          options = extract_options_from_args!(args)
+          # Obtain items affecting distance condition.
+          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 no explicit bounds were given, try formulating them from the point and distance given
+          bounds = formulate_bounds_from_distance(options, origin, units) unless bounds
+          # Apply select adjustments based upon action.
+          add_distance_to_select(options, origin, units, formula) if origin && action == :find
+          # Apply the conditions for a bounding rectangle if applicable
+          apply_bounds_conditions(options,bounds) if bounds
+          # Apply distance scoping and perform substitutions.
+          apply_distance_scope(options)
+          substitute_distance_in_conditions(options, origin, units, formula) if origin && options.has_key?(:conditions)
+          # Order by scoping for find action.
+          apply_find_scope(args, options) if action == :find
+          # Unfortunatley, we need to do extra work if you use an :include. See the method for more info.
+          handle_order_with_include(options,origin,units,formula) if options.include?(:include) && options.include?(:order) && origin
+          # Restore options minus the extra options that we used for the
+          # GeoKit API.
+          args.push(options)   
+        end
+        
+        # If we're here, it means that 1) an origin argument, 2) an :include, 3) an :order clause were supplied.
+        # Now we have to sub some SQL into the :order clause. The reason is that when you do an :include,
+        # ActiveRecord drops the psuedo-column (specificically, distance) which we supplied for :select. 
+        # So, the 'distance' column isn't available for the :order clause to reference when we use :include.
+        def handle_order_with_include(options, origin, units, formula)
+          # replace the distance_column_name with the distance sql in order clause
+          options[:order].sub!(distance_column_name, distance_sql(origin, units, formula))
+        end
+        
+        # Looks for mapping-specific tokens and makes appropriate translations so that the 
+        # original finder has its expected arguments.  Resets the the scope argument to 
+        # :first and ensures the limit is set to one.
+        def apply_find_scope(args, options)
+          case args.first
+            when :nearest
+              args[0] = :first
+              options[:limit] = 1
+              options[:order] = "#{distance_column_name} ASC"
+            when :farthest
+              args[0] = :first
+              options[:limit] = 1
+              options[:order] = "#{distance_column_name} DESC"
+          end
+        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)
+          distance = options[:range].last-(options[:range].exclude_end?? 1 : 0) if options.has_key?(:range)
+          if distance
+            res=GeoKit::Bounds.from_point_and_radius(origin,distance,:units=>units)
+          else 
+            nil
+          end
+        end
+        
+        # Replace :within, :beyond and :range distance tokens with the appropriate distance 
+        # where clauses.  Removes these tokens from the options hash.
+        def apply_distance_scope(options)
+          distance_condition = "#{distance_column_name} <= #{options[:within]}" if options.has_key?(:within)
+          distance_condition = "#{distance_column_name} > #{options[:beyond]}" if options.has_key?(:beyond)
+          distance_condition = "#{distance_column_name} >= #{options[:range].first} AND #{distance_column_name} <#{'=' unless options[:range].exclude_end?} #{options[:range].last}" if options.has_key?(:range)
+          [:within, :beyond, :range].each { |option| options.delete(option) } if distance_condition
+          
+          options[:conditions]=augment_conditions(options[:conditions],distance_condition) if distance_condition
+        end
+
+        # This method lets you transparently add a new condition to a query without
+        # worrying about whether it currently has conditions, or what kind of conditions they are
+        # (string or array).
+        # 
+        # Takes the current conditions (which can be an array or a string, or can be nil/false), 
+        # and a SQL string. It inserts the sql into the existing conditions, and returns new conditions
+        # (which can be a string or an array
+        def augment_conditions(current_conditions,sql)
+          if current_conditions && current_conditions.is_a?(String)
+            res="#{current_conditions} AND #{sql}"  
+          elsif current_conditions && current_conditions.is_a?(Array)
+            current_conditions[0]="#{current_conditions[0]} AND #{sql}"
+            res=current_conditions
+          else
+            res=sql
+          end
+          res
+        end
+
+        # Alters the conditions to include rectangular bounds conditions.
+        def apply_bounds_conditions(options,bounds)
+          sw,ne=bounds.sw,bounds.ne
+          lng_sql= bounds.crosses_meridian? ? "#{qualified_lng_column_name}<#{sw.lng} OR #{qualified_lng_column_name}>#{ne.lng}" : "#{qualified_lng_column_name}>#{sw.lng} AND #{qualified_lng_column_name}<#{ne.lng}"
+          bounds_sql="#{qualified_lat_column_name}>#{sw.lat} AND #{qualified_lat_column_name}<#{ne.lat} AND #{lng_sql}"
+          options[:conditions]=augment_conditions(options[:conditions],bounds_sql)          
+        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::IpGeocoder.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
+
+        # Augments the select with the distance SQL.
+        def add_distance_to_select(options, origin, units=default_units, formula=default_formula)
+          if origin
+            distance_selector = distance_sql(origin, units, formula) + " AS #{distance_column_name}"
+            selector = options.has_key?(:select) && options[:select] ? options[:select] : "*"
+            options[:select] = "#{selector}, #{distance_selector}"  
+          end   
+        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_conditions(options, origin, units=default_units, formula=default_formula)
+          original_conditions = options[:conditions]
+          condition = original_conditions.is_a?(String) ? original_conditions : original_conditions.first
+          pattern = Regexp.new("\s*#{distance_column_name}(\s<>=)*")
+          condition = condition.gsub(pattern, distance_sql(origin, units, formula))
+          original_conditions = condition if original_conditions.is_a?(String)
+          original_conditions[0] = condition if original_conditions.is_a?(Array)
+          options[:conditions] = original_conditions
+        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)
+          lat = deg2rad(origin.lat)
+          lng = deg2rad(origin.lng)
+          multiplier = units_sphere_multiplier(units)
+          case connection.adapter_name.downcase
+          when "mysql"
+            sql=<<-SQL_END 
+                  (ACOS(COS(#{lat})*COS(#{lng})*COS(RADIANS(#{qualified_lat_column_name}))*COS(RADIANS(#{qualified_lng_column_name}))+
+                  COS(#{lat})*SIN(#{lng})*COS(RADIANS(#{qualified_lat_column_name}))*SIN(RADIANS(#{qualified_lng_column_name}))+
+                  SIN(#{lat})*SIN(RADIANS(#{qualified_lat_column_name})))*#{multiplier})
+                  SQL_END
+          when "postgresql"
+            sql=<<-SQL_END 
+                  (ACOS(COS(#{lat})*COS(#{lng})*COS(RADIANS(#{qualified_lat_column_name}))*COS(RADIANS(#{qualified_lng_column_name}))+
+                  COS(#{lat})*SIN(#{lng})*COS(RADIANS(#{qualified_lat_column_name}))*SIN(RADIANS(#{qualified_lng_column_name}))+
+                  SIN(#{lat})*SIN(RADIANS(#{qualified_lat_column_name})))*#{multiplier})
+                  SQL_END
+          else
+            sql = "unhandled #{connection.adapter_name.downcase} adapter"
+          end        
+        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(origin.lat, units)
+          case connection.adapter_name.downcase
+          when "mysql"
+            sql=<<-SQL_END
+                  SQRT(POW(#{lat_degree_units}*(#{origin.lat}-#{qualified_lat_column_name}),2)+
+                  POW(#{lng_degree_units}*(#{origin.lng}-#{qualified_lng_column_name}),2))
+                  SQL_END
+          when "postgresql"
+            sql=<<-SQL_END
+                  SQRT(POW(#{lat_degree_units}*(#{origin.lat}-#{qualified_lat_column_name}),2)+
+                  POW(#{lng_degree_units}*(#{origin.lng}-#{qualified_lng_column_name}),2))
+                  SQL_END
+          else
+            sql = "unhandled #{connection.adapter_name.downcase} adapter"
+          end
+        end
+      end
+    end
+  end
+end
+
+# Extend Array with a sort_by_distance method.
+# This method creates a "distance" attribute on each object, 
+# calculates the distance from the passed origin,
+# and finally sorts the array by the resulting distance.
+class Array
+  def sort_by_distance_from(origin, opts={})
+    distance_attribute_name = opts.delete(:distance_attribute_name) || 'distance'    
+    self.each do |e|
+      e.class.send(:attr_accessor, distance_attribute_name) if !e.respond_to? "#{distance_attribute_name}="
+      e.send("#{distance_attribute_name}=", origin.distance_to(e,opts))
+    end
+    self.sort!{|a,b|a.send(distance_attribute_name) <=> b.send(distance_attribute_name)}
+  end
+end
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