Module: DataMapper::GeoKit::ActsAsMappable::ClassMethods

Defined in:
lib/dm-geokit/acts_as_mappable.rb

Overview

Class method to mix into active record.

Instance Method Summary collapse

Instance Method Details

#acts_as_mappable(options = {}) ⇒ Object

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.



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# File 'lib/dm-geokit/acts_as_mappable.rb', line 49

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