How to do tagging in Rails with gem ‘Acts_as_taggable_on’

Tagging is a way to give a keyword and search by that particular keyword. In Rails “acts-as-taggable-on” is one of the popular gem for tagging. With ‘acts_as_taggable_on’, you can tag a single model on several contexts, such as skills, interests, and awards

Below is an example to describe how to implement it in a Rails application:

Step#1
• Add the gem to your Gemfile:

gem ‘acts-as-taggable-on'

• Then run the bundle

bundle install

Step#2

• Run the generator command

rails g acts_as_taggable_on:migration

• Run the migration file

rake db:migrate

This migration will create two tables in the database: tags and taggings.
Step#3
Now you have to modify your model where you want to implement tagging.
For example, we like to implement the tagging on Post model.

• Add the following codes to the “Post” model to have acts_as_taggable and also add a “tag_list” field to the attr_accessible list.

attr_accessible :content, :name, :tag_list
acts_as_taggable

Step#4

• Add a new field to your post form.

<%= f.label :tag_list, "Tags (separated by commas)" %>
<%= f.text_field :tag_list %>

Step#5

• Add the following codes, if you want to show the tags for the tagged posts in the listing page:

<% @posts.each do |post| %>
<h2><%= link_to post.name, post %></h2>
<%= simple_format post.content %>
<p>
Tags: <%= raw post.tag_list.map { |t| link_to t, tag_path(t) }.join(', ') %>
</p>
<% end %>

Step#6

• Modify your route file to get the tags

get 'tags/:tag', to: 'posts#index', as: :tag

Step#7

• Modify your controller:

class PostsController < ApplicationController
def index
if params[:tag]
@posts = Post.tagged_with(params[:tag])
else
@posts = Post.all
end
end
end

Voila! You have done it.