Update geocode latitude and longitude everytime address is updated

Question

I have this in my shop.rb:

def geocode_address
  if !address_geo.blank?
    geo=Geokit::Geocoders::MultiGeocoder.geocode(address_geo)
    errors.add(:address, "Could not Geocode address") if !geo.success
    self.lat, self.lng = geo.lat,geo.lng if geo.success
  end
end

# Checks whether this object has been geocoded or not. Returns the truth
def geocoded?
  lat? && lng?
end

And in my shops_controller.rb:

def update
@shop = Shop.find(params[:id])
if @shop.update_attributes(params[:shop])
  flash[:notice] = "Successfully saved."
  redirect_to shop_path(@shop, :type => @shop.shop_type)
else
  render :action => :edit
end
end

Now when the user first creates the entry, the address is geocoded, with latitude and longitude saved to the database.

But when the user updates the address, the latitude and longitude will not be geocoded anymore, and thus still using the old latitude and longitude which is the first save.

How do I write to have Rails re-geocode everytime an entry is update?

I can't depend on just the address because there is a bug in geokit that when I try to show multiple maps based on address, only the last one is shown.

I'm using geokit, Gmaps, Google Maps...

Thanks.

Answer 1

I put this in my model:

  before_validation_on_update :geocode_address

Answer 2

If the user changes their address can't you essentially handle it the same way as a new address? You basically have 2 new addresses you just need to link the newly created address with the user's account and everything should work.

Answer 3

The new syntax to perform validation before a specific action is:

     before_validation :geocode_address, on: :update

or if you have more than one action,

    before_validation :geocode_address, on: %i[create update]

This will ensure that before validation and saving to the database is done, your method (geocode_address) runs first.

Answer 4

Better to use Geocoder Gem https://github.com/alexreisner/geocoder

Actually in your model shop.rb you will need to to add the following to ensure that the longitude and latitude fields get updated in your shop table every time a user updates the address in your view.

Gemfile

gem 'geocoder', '~> 1.4'

You should add two fields to the Shop table, longitude and latitude, make sure they are both floats, make the migration if you have not done this already.

Assuming that address is a field and it exists in your shop table, and assuming that location.html.erb is a view in your shop and in that view you have something like this

<%= f.text_field :address, placeholder: "Your Shop's Address", class: "form-control", required: true, id: "shopaddress" %>

I also assuming that, when you created your Shop model you added the property active:boolean and user:references to know is a shop is active or not, and know to which user does the shop belong to. So one user has many shops.

The ID shopaddress, i am including here just in case you want to use Geocomplete gem with Google Maps API with the Places Library. But you do not need it there.

In shop.rb

geocoded_by :address
# Will Update if changed
after_validation :geocode, if: :address_changed?

Of course in your controller you will want to ensure that whoever is updating the address is authorized first and then run the methods. So instead of having to repeat your self. You'll probably want to create something like this in your shop controller.

In shops_controller.rb

class ShopsController < ApplicationController
  # If your shop owners are creating many shops you will want to add 
  #your methods here as well with index. Eg. :create, :new
  # In case you have a view shop page to show all people 

  before_action :set_shop, except: [:index]

  before_action :authenticate_user!, except: [:show]

  # I am assuming that you also want to update other fields in your 
  #shop and the address isn't the only one.

  before_action :is_user_authorised, only: [:name_x, :name_y, :name_z, :location, :update]

  def index
    @shops = current_user.shops
  end

  def show
    @photos = @shop.photos
    @product_reviews = @shop.product_reviews
  end

  def name_x
  end

  def name_y
  end

  def name_z
  end

  def location
  end

  def update
    new_params = shop_params
    # To ensure the shop is actually published
    new_params = shop_params.merge(active: true) if is_shop_ready

    if @shop.update(new_params)
      flash[:notice] = "Saved..."
    else
      flash[:alert] = "Oh oh hmm! something went wrong..."
    end
    redirect_back(fallback_location: request.referer)
  end

  private

    def set_shop
      @shop = Shop.find(params[:id])
    end

    def is_user_authorised
      redirect_to root_path, alert: "You don't have permission" unless 
      current_user.id == @shop.user_id
    end

    # You can play with this here, what defines a ready shop?
    def is_shop_ready
      !@shop.active && !@shop.name_x.blank? && 
      !@shop.name_y.blank? && !@shop.name_z.blank? && 
      !@shop.address.blank?
    end

    # Here you are allowing the authorized user to require her shop and it's properties, so that she can update them with update method above.
    # eg_summary, eg_shop_type, eg_shop_name are just additional #example properties that could have been added when you iniitially created your Shop model
    def shop_params
      params.require(:shop).permit(:address, :active, :eg_shop_name, :eg_shop_summary, :eg_shop_type)
    end

end