NoMethodError using activerecord_postgis_adapter

问题

I tried installing activerecord-postgis-adapter as per the README but am unable to create the model instance as I keep getting the error mentioned below:

NoMethodError: undefined method `point' for nil:NilClass

Here are what my different files look like:

Location.rb (the model, updated code)

# == Schema Information
#
# Table name: locations
#
#  id             :integer          not null, primary key
#  locatable_id   :integer
#  locatable_type :string
#  created_at     :datetime         not null
#  updated_at     :datetime         not null
#  coordinates    :geography({:srid point, 4326
#

class Location < ActiveRecord::Base

    #self.rgeo_factory_generator = RGeo::Geos.factory_generator
    #set_rgeo_factory_for_column(:coordinates, 
    #   RGeo::Geographic.spherical_factory(:srid => 4326) )

    locFactory = RGeo::ActiveRecord::SpatialFactoryStore.instance.factory(:geo_type => 'point')

    belongs_to  :locatable,
        polymorphic: true

    validates   :locatable, presence: true

    attr_accessor   :longitude, :latitude

end

Gemfile

gem 'rgeo'
gem 'rgeo-activerecord'
gem 'activerecord-postgis-adapter'

config/application.rb

require 'rails/all'
#require 'active_record/connection_adapters/postgis_adapter/railtie'
#require "#{Rails.root}/lib/rgeo"

config/database.yml

development:
<<: *default
database: geoproject-api_development
adapter: postgis
schema_search_path: "public,postgis"

After adding a record when I try to retrieve it, I get the following:

irb(main):003:0> lala = Location.first
Location Load (1.6ms) SELECT "locations".* FROM "locations" ORDER BY "locations"."id" ASC LIMIT 1
(Object doesn't support #inspect) 
irb(main):004:0> lala.class.name => "Location" 
irb(main):005:0> puts lala
#<Location:0x007fdfd4bb2860>
=> nil
irb(main):006:0> puts lala.inspect
NoMethodError: undefined method point' for nil:NilClass

Wondering why that it is or how can I fix it? More specifically, why is it a NilClass and why is the #inspect not being found?

From my schema.rb

 create_table "locations", force: :cascade do |t|
    t.integer   "locatable_id"
    t.string    "locatable_type"
    t.datetime  "created_at",                                                              null: false
    t.datetime  "updated_at",                                                              null: false
    t.geography "coordinates",    limit: {:srid=>4326, :type=>"point", :geographic=>true}
  end

I am using Rails 4.2.1.

回答1:

As of version 3.0.0 you can't set column specific geo factory properties. And the method set_rgeo_factory_for_column is removed and deprecated. You can, however configure RGeo factory application wide. For example in your initializer.

RGeo::ActiveRecord::SpatialFactoryStore.instance.tap do |config|
  # By default, use the GEOS implementation for spatial columns.
  config.default = RGeo::Geos.factory_generator

  # But use a geographic implementation for point columns.
  config.register(RGeo::Geographic.spherical_factory(srid: 4326), geo_type: "point")
end

来源：https://stackoverflow.com/questions/30834862/nomethoderror-using-activerecord-postgis-adapter

标签

ruby-on-rails

PostGIS

rgeo