tags formongoid collections.

mongoid_tags.rb

module Mongoid
  module Document
    module Taggable
      def self.included(base)
        base.class_eval do |base_document|
          base_document.field :tags, :type => Array, :default => []
          base_document.index :tags

          include InstanceMethods
          extend ClassMethods
        end
      end

      module InstanceMethods
        def tag_list=(tags)
          if tags.is_a?(Array)
            self.tags = tags.compact
          else
            self.tags = tags.split(",").collect{ |t| t.strip }.delete_if{ |t| t.blank? }
          end
        end

        def tag_list
          self.tags.join(", ") if tags
        end

        def has_tags?( tags_to_check )
          tags_to_check = tags_to_check.split(",") unless tags_to_check.is_a?(Array)
          tags_to_check = tags_to_check.map(&:strip)
          return true if self.tags.sort & tags_to_check.sort == tags_to_check.sort
          false
        end

      end

      module ClassMethods
        def tags
          all.only(:tags).collect{ |ms| ms.tags }.flatten.uniq.compact
        end

        def tagged_with(_tags)
          _tags = [_tags] unless _tags.is_a? Array
          criteria.in(:tags => _tags).to_a
        end
      end

    end
  end
end

module Mongoid
  module Document
    module Taggable

      module Whitelist

        def self.included(base)
          base.class_eval do |document|
            alias_method :"not_white_listed_tags=", :"tag_list="
            include InstanceMethods
          end
        end

        module InstanceMethods

          def tag_list=(tags)
            if self.method(:"white_tag?")
              filtered_tags = tags.split(",").collect{ |t| t.strip }.delete_if do |t|
                 !self.white_tag?(t)
              end
              self.not_white_listed_tags=(filtered_tags)
            else
              self.not_white_listed_tags=(tags)
            end
          end

        end

      end

    end
  end
end

tags_spec.rb

# initial simple test case. 
require 'spec_helper'

class TestTags
  include Mongoid::Document
  include Mongoid::Document::Taggable
end

describe "Tags" do

  before(:each) do
    @test_tags = TestTags.new
  end

  it "should build testtag object and save it without any problems" do
    @test_tags.tag_list.should be_empty
    @test_tags.tag_list.should_not be_nil
  end

  it "should be able to add tags, save them and load" do
    @test_tags.tag_list = "jakub, kuba, michal, kuba, jakub"
    ["kuba", "jakub", "michal"].map{|tag| @test_tags.tag_list.should be_include(tag) }
    @test_tags.save
    @test_tags.reload
    ["kuba", "jakub", "michal"].map{|tag| @test_tags.tag_list.should be_include(tag) }
  end

end