Wednesday, 7 December 2011


Tagging is pretty popular these days, and it was time to add it to our site. Unfortunately, lots of the gems are old, and it's had to know if that means "good and has stuck around" or "buggy, obsolete and no longer supported".

The rubytoolbox page on rails tagging has several gems - most of which are marked as inactive now. The only one that looked like it had any recent activity is: acts-as-taggable-on. It's also the top-most-downloaded, so that looked good.

Best news: it is rails-3 compatible AND supports a recent build-version that is still Rails-2 compatible. As I've mentioned before, my current client is still on Rails-2 - because the upgrade pain is not currently outweighed by the new features.

The only annoyance is that the rdoc only has rails-3 post-install instructions rails generate acts_as_taggable_on:migration. These don't work for rails-2, and if you try just substituting "script/" for "rails ", it'll give you an error saying: Couldn't find 'acts_as_taggable_on:migration' generator

I had to hack about a bit to find the new migration name, but what you need is: script/generate acts_as_taggable_on_migration

After that I used this extremely good tutorial on tagging with acts-as-taggable-on.

I don't like the tag-cloud style of tag-selection, and instead prefer something much more like Stack Overflow. So I created my own tag-list as per the code below.

It lists all current tags for the class (assuming similar code setup to the tutorial above), and filter based on that keyword - incorporating any existing search or pagination conditions you already have. It will highlight the current keyword, and change that link to a "deselect if you click" link.

    # code in index page
    <% @tags.sort_by(&:count).reverse.each do |k| %>
      <% url_opts = {:action => "index", :controller => "posts"}
         link_name = "#{} (#{k.count})"
      <% if @keyword == %>
        <%= link_to link_name, url_opts.merge(:keyword => nil), :class => "tag current_tag", :title => "Click again to see all" %>
      <% else %>
        <%= link_to link_name,  url_opts.merge(:keyword =>, :class => "tag", :title => "Click to filter by #{}" %>
      <% end %>
    <% end %>

   # code in controller
   options = {} # any search/pagination conditions go here
   @tags = Post.tag_counts_on(:keywords)
   klass = Post
   klass = klass.tagged_with(@keyword) if (@keyword = params[:keyword]).present?
   @posts = klass.paginate( options )

  /**** and associated tag-cloud styles ****/
  /* basic tag-box */
  .tag {
    background-color: #eee;
    border: 2px solid #ccc;
    color: orange;
    border-radius: 7px;
    -moz-border-radius: 7px;
    padding: 2px 15px;
    text-decoration: none;
  .current_tag {
    background-color: #ddd;
    color: orange;
    border: 2px solid orange;
    border-radius: 7px;
    -moz-border-radius: 7px;
    font-weight: bold;
  .tag:hover, .current_tag:hover {
    background-color: #bbb;
    color: red;
    border: 2px solid red;
    border-radius: 7px;
    -moz-border-radius: 7px;

Next up is to figure out ye olde ajax auto-suggest when I add them.


Pravin Mishra said...

nice post, helped me a lot to start. Thank you for your time.

Pravin Mishra said...

nice post, got as first link on google. Helped me a lot to start. thank you for your time.

Liutauras Valiukas said...

Thanx, it was very usefull to me!