Tags

We will use acts_as_taggable_on_steroids (one of many tagging plugins for RoR) and will_paginate (one of many pagination plugins for RoR)

acts_as_taggable_on_steroids

Install: 
script/plugin source http://svn.viney.net.nz/things/rails/plugins/
script/plugin install acts_as_taggable_on_steroids

will_paginate

Install: 
script/plugin install svn://errtheblog.com/svn/plugins/will_paginate

Create db structure

ruby script/generate acts_as_taggable_migration
rake db:migrate

Edit the model

app/models/coffee_house.rb

add the line:

acts_as_taggable

Adding and displaying tags

  1. tag input field -- app/views/coffee_house/_form.rhtml: 
    
<p><label for="coffee_house_tag_list">Tags</label><br>
<%= text_field 'coffee_house', 'tag_list' %></p>
  2. display tags -- app/views/coffee_house/show.rhtml: 
    <%= @coffee_house.tag_list.join(', ') %>

Tag cloud

  1. app/helpers/application.rb 
    include TagsHelper
  2. app/controllers/coffee_house_controller.rb#list 
      
  def list
    @coffee_house_pages, @coffee_houses = paginate :coffee_houses, :per_page => 10
    @tags = CoffeeHouse.tag_counts
  end
  3. public/stylesheets/coffee_house.css 
    
  .tag_cloud {width:500px;border:1px solid black;padding:5px}
  .css1 { font-size: 1.0em; }
  .css2 { font-size: 1.2em; }
  .css3 { font-size: 1.4em; }
  .css4 { font-size: 1.6em; }
  4. app/views/coffee_house/list.rhtml 
    
<div class="tag_cloud">
<% tag_cloud @tags, %w(css1 css2 css3 css4) do |tag, css_class| %>
  <%= link_to tag.name, { :action => :list_tagged, :id => tag.name }, :class => css_class %>
<% end %>
<div>

Tag search

  1. We need a list_tagged action in the controller, that will perform a search on coffee houses tagged with the given tag and provide pagination for the results. The built-in RoR paginator is not best suited for this (plus it will no longer be a built-in in RoR 2.0), so we'll use will_paginate. app/controllers/coffee_house_controller.rb 
    
 def list_tagged
    if params[:id]
      @tag = params[:id]
      params[:page]||=1
     @coffee_houses = WillPaginate::Collection.create(params[:page],5) do |pager|

       result = CoffeeHouse.find_tagged_with(@tag,{:limit=>pager.per_page,:offset=>pager.offset})
       pager.replace(result)
       options = CoffeeHouse.find_options_for_find_tagged_with(@tag);
       options.delete(:select)
       options.merge({:select => 'count(distinct coffee_houses.id)'})
       pager.total_entries = CoffeeHouse.count(options)
     end
    else
      redirect_to :action => 'list'
    end
  end
  2. We need a view to display search results. It will not be very different from the list view, so let's design it the DRY way:
  3. create a list element partial -- app/views/coffee_house/_list_element.rhtml 
    
<div class="coffee_house">
  <% photo = coffee_house.photos.first %>
  <%= image_tag(photo.public_filename('thumb'),:class=>'thumb') if photo %>
  <div class="info">

<h3><%= link_to coffee_house.name, :controller => 'coffee_house', :action => 'show', :id => coffee_house %></h3>
    <p><%= link_to coffee_house.company.name, :controller => 'company', :action => 'show', :id=>coffee_house.company if coffee_house.company %></p>
    <p><%= "#{coffee_house.street} #{coffee_house.building_number}" %></p>
    <p><%= link_to coffee_house.city.name, :controller => 'city', :action => 'show', :id => coffee_house.city if coffee_house.city %></p>
</div>
<div style="clear:both"></div>
</div>
  4. change app/views/coffee_house/list.rhtml to use the partial 
    
<% for coffee_house in @coffee_houses %>
<%= render :partial => 'list_element', :locals => {'coffee_house' => coffee_house} %>
<div>
  <%= link_to 'Show', :action => 'show', :id=>coffee_house %>
  <%= link_to 'Edit', :action => 'edit', :id => coffee_house %>
  <%= link_to 'Destroy', {:action => 'destroy', :id=>coffee_house}, :method => :post %>
</div>
<% end %>
  5. add style definitions to public/stylesheets/coffee_house.css 
    
.coffee_house{
  width: 400px;
  border: 1px solid #000000;
  margin: 10px;
}

.thumb{
  float:left;
}

.info{
  width: 300px;
  float:right;
}
  6. check if coffee_house/list displays correctly
  7. create app/views/coffee_house/list_tagged.rhtml 
    
<h1>Listing Coffee Houses tagged with <%= @tag %></h1>

<% for coffee_house in @coffee_houses %>
<%= render :partial => 'list_element', :locals => {'coffee_house' => coffee_house} %>
<% end %>

<%= will_paginate @coffee_houses %>
  8. click on a tag in tag cloud to test