Question

I am working on a prototyp (rails 2.2.2) to create a similiar page structure as the business directory from http://www.redbeacon.com/s/b/.

Goal should be to have the following paths: mysite.com/d/state/location/ …which displays an index of something. So far, I did the following…

Controllers and models:

$ ruby script/generate controller Directories index show
$ ruby script/generate controller States index show
$ ruby script/generate controller Locations index show
$ ruby script/generate model State name:string abbreviation:string
$ ruby script/generate model Location name:string code:string state_id:integer
$ rake db:migrate

routes:

map.states '/d', :controller => 'states', :action => 'index'
map.locations '/d/:state', :controller => 'locations', :action => 'index'
map.directories '/d/:state/:location', :controller => 'directories', :action => 'index'

…built in the models the relations:

class State < ActiveRecord::Base
  has_many :locations
end

class Location < ActiveRecord::Base
  belongs_to :states
end

…added actions to the controllers:

class StatesController < ApplicationController
  def index
    @all_states = State.find(:all)
  end
end

class LocationsController < ApplicationController
 def index
    @all_locations = Location.find(:all)
    @location = Location.find_by_id(params[:id])
  end
end

class DirectoriesController < ApplicationController
  def index
    @location = Location.find_by_id(params[:id])
    @all_tradesmen = User.find(:all)
  end
end

The States Index View

<h1>States#index</h1>
<p>Find me in app/views/states/index.html.erb</p>
<br><br>
<% for state in @all_states %>
  <%= link_to state.name, locations_path(state.abbreviation.downcase) %>
<% end %>

The Locations Index View

<h1>Locations#index</h1>
<p>Find me in app/views/locations/index.html.erb</p>
<br><br>

<% for location in @all_locations %>
  <%= link_to location.name, directories_path(location.state.abbreviation, location.name) %>
<% end %>

But I am stuck, I get the following error message:

NoMethodError in Locations#index

Showing app/views/locations/index.html.erb where line #6 raised:

undefined method `state' for #<Location:0x104725920>

Extracted source (around line #6):

3: <br><br>
4: 
5: <% for location in @all_locations %>
6:   <%= link_to location.name, directories_path(location.state.abbreviation, location.name) %>
7: <% end %>

Any Ideas why this error message pops up? Or generally any ideas for a better approach?

Answer 1

The part of the code you should look at is:

class Location < ActiveRecord::Base
  belongs_to :states
end

and it should be

class Location < ActiveRecord::Base
  belongs_to :state
end

Another note, although not related to the error you are getting, Ruby programmers usually prefer array.each than for item in array.