HasTags

HasTags is a lightweight library for easily adding tags to your ActiveRecord models.

Installation

Add this line to your application's Gemfile:

gem 'has_tags'

And then execute:

$ bundle

Or install it yourself as:

$ gem install has_tags

Usage

First, you must run rails g has_tags:install to install the tag migrations.

Once the migrations are installed, run rake db:migrate.

Now choose a model to add tags to. Let's use Post as an example. All you have to do is add has_tags to the model class definition:

  class Post < ActiveRecord::Base
    has_tags
  end

Your post class can now have associated tags.

To set tags on a Post instance, whitelist the tag_list parameter in your controller:

class PostController < ActiveRecord::Base
  # ...

  private

  def post_params
    params.require(:post).permit(:param1, :param2, :tag_list)
  end
end

tag_list should be a string with tags separated by commas, or colons to create a context tag.

To find all instances of an object associated with a certain tag, use the tagged_with class method, which takes an array of tag names to search by:

Post.tagged_with(["Sports"]) # => All posts tagged with "Sports"

Since it accepts an array of tag names, you can something like this:

Post.tagged_with(["Sports", "Lacrosse", "2014"]) # => All posts tagged with "Sports", "Lacrosse", and "2014"

Input to tagged_with doesn't need to be an exact match, making it good for searching:

search_term = params[:search_term] # Let's say a user input "sport"

Post.tagged_with([search_term]) # => All posts tagged with "Sports"

You can also get all of the top level tags for a specific class:

Post.top_level_tags # => All tags that are associated with a "Post" object and that have have no parent tags

Or for all classes that have tags:

HasTags::Tag.top_level_tags # => All tags that have no parent tags

Examples

For creating top-level tags, a user can type in tags only separated by commas:

"Sports, Food"

For creating tags within tags, where to top-level tag acts as the context or parent for the child tag, separate the tags by colons:

"Sports:Hockey, Food"

This creates three tags: Sports, Hockey and Food. Sports is now the context in which Hockey lives. Now we can call:

context = HasTags::Tag.find_by(name: "Sports")

context.tags # => Hockey tag

The context tag syntax can be nested like so:

"Sports:Hockey:Strategy"

strategy = HasTags::Tag.find_by(name: "Strategy")

hockey = strategy.context # => Hockey tag

hockey.context # => Sports tag

Contributing

1. Fork it
2. Create your feature branch (git checkout -b my-new-feature)
3. Commit your changes (git commit -am 'Add some feature')
4. Push to the branch (git push origin my-new-feature)
5. Create new Pull Request