创建一个目录结构（带有嵌套路由+漂亮的url，...）

Question

我正在开发一个原型（rails 2.2.2）来创建一个类似的页面结构作为 http 的业务目录://www.redbeacon.com/s/b/。

目标应该是具有以下路径：mysite.com/d/state/location/ ...显示某些内容的索引。到目前为止，我做了以下操作...

控制器和模型：

$ 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

路线：

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

...在模型中构建了关系：

class State < ActiveRecord::Base
  has_many :locations
end

class Location < ActiveRecord::Base
  belongs_to :states
end

...向控制器添加了操作：

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

状态索引视图

<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 %>

位置索引视图

<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 %>

但是我被困住了，我明白了以下错误消息：

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 %>

有什么想法为什么会弹出此错误消息吗？或者通常有更好方法的想法吗？

Answer 1

您应该查看的代码部分是：

class Location < ActiveRecord::Base
  belongs_to :states
end

并且应该是

class Location < ActiveRecord::Base
  belongs_to :state
end

另一个注意事项，尽管与您收到的错误无关，但 Ruby 程序员通常更喜欢 array.each 而不是 对于数组中的项目。