paper_trail & rgeo-activerecord integration

paper_trail.rb

# config/initializers/paper_trail.rb
require "paper_trail_attribute_serializer_spatial_support"
PaperTrail::AttributeSerializers::AttributeSerializerFactory.include(PaperTrailAttributeSerializerSpatialSupport)

paper_trail_attribute_serializer_spatial_support.rb

# lib/paper_trail_attribute_serializer_spatial_support.rb
module PaperTrailAttributeSerializerSpatialSupport
  extend ActiveSupport::Concern
  AR_SPATIAL = "ActiveRecord::Type::Spatial".freeze

  included do
    singleton_class.send(:alias_method, :for_original, :for)

    def self.for(klass, attr)
      active_record_serializer = klass.type_for_attribute(attr)

      if active_record_serializer.class.name == AR_SPATIAL
        SpatialSerializer.new
      else
        for_original(klass, attr)
      end
    end
  end

  class SpatialSerializer
    def serialize(geospatial_object)
      geospatial_object.to_s
    end

    def deserialize(string)
      DEFAULT_RGEO_FACTORY.parse_wkt(string)
    end
  end
end

PAPERTRAIL_RGEO.md

The default serializer will serialize the entire ruby object of your geospatial column. This custom serializer will serialize it to WKT (WKB isn't an option here without casting). This is much more efficient than serializing the entire ruby object, and much safer.

rgeo.rb

# config/initializers/rgeo.rb
DEFAULT_RGEO_FACTORY = RGeo::Geographic.spherical_factory(srid: 3857)

RGeo::ActiveRecord::SpatialFactoryStore.instance.tap do |config|
  config.default = DEFAULT_RGEO_FACTORY
end