通过街道地址，通过Geocoder gem地理编码更新经度/纬度

Question

How can I update the latitude and longitude coordinates using geocoder gem given the following models and relationship. I have a Location model with latitude and longitude attributes that belong to my Event model. The latitude and longitude automatically get fetched and stored in latitude and longitude attributes of my Location model. My Event model has a field venue_address which is what I geocode by.

class Location < ActiveRecord::Base
  belongs_to :event
    geocoded_by :venue_address
    after_validation :geocode
end

AND this is my Event model with has_one :location relation

class Event < ActiveRecord::Base
    has_one     :location,  dependent: :destroy
end 

Next is my Event create method where I build the relationship.

class EventsController < ApplicationController
  def create
    @event = Event.new(event_params)
    # Builds longitude and latitude coordinates based on a valid street address
    # and saves it to Location table
    @event.build_location
...
  end 
end 

When I update the address of an event I would like to geocode the new coordinates and save the coordinates to their respective field in Location model.

I am having trouble accomplishing this. Any ideas or suggestions?

Answer 1

Try something like this

class Location < ActiveRecord::Base
  belongs_to :event
  geocoded_by :event_venue_address
  after_validation :geocode

  def event_venue_address
    event.venue_address
  end

end

or just delegate to event model

delegate :venue_address, to: event, prefix: true

Here is the example for the readme

If your model has street, city, state, and country attributes you might do something like this:

geocoded_by :address

def address
  [street, city, state, country].compact.join(', ')
end

Hope that helps