= Changed in this fork:

- The save_owned_tags method was modified in order to avoid old_tags deletion when updating the user owned_tags

-------------------------------------

= ActsAsTaggableOn
{<img src="https://secure.travis-ci.org/mbleigh/acts-as-taggable-on.png" />}[http://travis-ci.org/mbleigh/acts-as-taggable-on]

This plugin was originally based on Acts as Taggable on Steroids by Jonathan Viney.
It has evolved substantially since that point, but all credit goes to him for the
initial tagging functionality that so many people have used.

For instance, in a social network, a user might have tags that are called skills,
interests, sports, and more. There is no real way to differentiate between tags and
so an implementation of this type is not possible with acts as taggable on steroids.

Enter Acts as Taggable On. Rather than tying functionality to a specific keyword
(namely "tags"), acts as taggable on allows you to specify an arbitrary number of
tag "contexts" that can be used locally or in combination in the same way steroids
was used.

== Installation

=== Rails 2.x

Not supported any more! It is time for update guys.

=== Rails 3.x

To use it, add it to your Gemfile:

  gem 'acts-as-taggable-on', '~> 2.3.1'

==== Post Installation

1. rails generate acts_as_taggable_on:migration
2. rake db:migrate

== Testing

Acts As Taggable On uses RSpec for its test coverage. Inside the gem
directory, you can run the specs for RoR 3.x with:

  rake spec

== Usage

    class User < ActiveRecord::Base
      # Alias for <tt>acts_as_taggable_on :tags</tt>:
      acts_as_taggable
      acts_as_taggable_on :skills, :interests
    end

    @user = User.new(:name => "Bobby")
    @user.tag_list = "awesome, slick, hefty"      # this should be familiar
    @user.skill_list = "joking, clowning, boxing" # but you can do it for any context!
    @user.skill_list                              # => ["joking","clowning","boxing"] as TagList
    @user.save

    @user.tags # => [<Tag name:"awesome">,<Tag name:"slick">,<Tag name:"hefty">]
    @user.skills # => [<Tag name:"joking">,<Tag name:"clowning">,<Tag name:"boxing">]

    @frankie = User.create(:name => "Frankie", :skill_list => "joking, flying, eating")
    User.skill_counts # => [<Tag name="joking" count=2>,<Tag name="clowning" count=1>...]
    @frankie.skill_counts

To preserve the order in which tags are created use acts_as_ordered_taggable:

    class User < ActiveRecord::Base
      # Alias for <tt>acts_as_ordered_taggable_on :tags</tt>:
      acts_as_ordered_taggable
      acts_as_ordered_taggable_on :skills, :interests
    end

    @user = User.new(:name => "Bobby")
    @user.tag_list = "east, south"
    @user.save

    @user.tag_list = "north, east, south, west"
    @user.save

    @user.reload
    @user.tag_list # => ["north", "east", "south", "west"] 


=== Finding Tagged Objects

Acts As Taggable On utilizes named_scopes to create an association for tags.
This way you can mix and match to filter down your results, and it also improves
compatibility with the will_paginate gem:

    class User < ActiveRecord::Base
      acts_as_taggable_on :tags, :skills
      scope :by_join_date, order("created_at DESC")
    end

    User.tagged_with("awesome").by_date
    User.tagged_with("awesome").by_date.paginate(:page => params[:page], :per_page => 20)

    # Find a user with matching all tags, not just one
    User.tagged_with(["awesome", "cool"], :match_all => true)

    # Find a user with any of the tags:
    User.tagged_with(["awesome", "cool"], :any => true)

    # Find a user that not tags with awesome or cool:
    User.tagged_with(["awesome", "cool"], :exclude => true)

    # Find a user with any of tags based on context:
    User.tagged_with(['awesome, cool'], :on => :tags, :any => true).tagged_with(['smart', 'shy'], :on => :skills, :any => true)

  You can also use :wild => true option along with :any or :exclude option. It will looking for %awesome% and %cool% in sql.

  Tip: User.tagged_with([]) or '' will return [], but not all records.

=== Relationships

You can find objects of the same type based on similar tags on certain contexts.
Also, objects will be returned in descending order based on the total number of
matched tags.

    @bobby = User.find_by_name("Bobby")
    @bobby.skill_list # => ["jogging", "diving"]

    @frankie = User.find_by_name("Frankie")
    @frankie.skill_list # => ["hacking"]

    @tom = User.find_by_name("Tom")
    @tom.skill_list # => ["hacking", "jogging", "diving"]

    @tom.find_related_skills # => [<User name="Bobby">,<User name="Frankie">]
    @bobby.find_related_skills # => [<User name="Tom">]
    @frankie.find_related_skills # => [<User name="Tom">]

=== Dynamic Tag Contexts

In addition to the generated tag contexts in the definition, it is also possible
to allow for dynamic tag contexts (this could be user generated tag contexts!)

    @user = User.new(:name => "Bobby")
    @user.set_tag_list_on(:customs, "same, as, tag, list")
    @user.tag_list_on(:customs) # => ["same","as","tag","list"]
    @user.save
    @user.tags_on(:customs) # => [<Tag name='same'>,...]
    @user.tag_counts_on(:customs)
    User.tagged_with("same", :on => :customs) # => [@user]

=== Tag Ownership

Tags can have owners:

    class User < ActiveRecord::Base
      acts_as_tagger
    end

    class Photo < ActiveRecord::Base
      acts_as_taggable_on :locations
    end

    @some_user.tag(@some_photo, :with => "paris, normandy", :on => :locations)
    @some_user.owned_taggings
    @some_user.owned_tags
    @some_photo.locations_from(@some_user) # => ["paris", "normandy"]
    @some_photo.owner_tags_on(@some_user, :locations) # => [#<ActsAsTaggableOn::Tag id: 1, name: "paris">...]
    @some_photo.owner_tags_on(nil, :locations) # => Ownerships equivalent to saying @some_photo.locations
    @some_user.tag(@some_photo, :with => "paris, normandy", :on => :locations, :skip_save => true) #won't save @some_photo object

=== Dirty objects

    @bobby = User.find_by_name("Bobby")
    @bobby.skill_list # => ["jogging", "diving"]

    @boddy.skill_list_changed? #=> false
    @boddy.changes #=> {}

    @bobby.skill_list = "swimming"
    @bobby.changes.should == {"skill_list"=>["jogging, diving", ["swimming"]]}
    @boddy.skill_list_changed? #=> true

    @bobby.skill_list_change.should == ["jogging, diving", ["swimming"]]

=== Tag cloud calculations

To construct tag clouds, the frequency of each tag needs to be calculated.
Because we specified +acts_as_taggable_on+ on the <tt>User</tt> class, we can
get a calculation of all the tag counts by using <tt>User.tag_counts_on(:customs)</tt>. But what if we wanted a tag count for
an single user's posts? To achieve this we call tag_counts on the association:

  User.find(:first).posts.tag_counts_on(:tags)

A helper is included to assist with generating tag clouds.

Here is an example that generates a tag cloud.

Helper:

  module PostsHelper
    include ActsAsTaggableOn::TagsHelper
  end

Controller:

  class PostController < ApplicationController
    def tag_cloud
      @tags = Post.tag_counts_on(:tags)
    end
  end

View:

  <% tag_cloud(@tags, %w(css1 css2 css3 css4)) do |tag, css_class| %>
    <%= link_to tag.name, { :action => :tag, :id => tag.name }, :class => css_class %>
  <% end %>

CSS:

  .css1 { font-size: 1.0em; }
  .css2 { font-size: 1.2em; }
  .css3 { font-size: 1.4em; }
  .css4 { font-size: 1.6em; }

== Configuration

If you would like to remove unused tag objects after removing taggings, add

  ActsAsTaggableOn.remove_unused_tags = true

If you want force tags to be saved downcased:

  ActsAsTaggableOn.force_lowercase = true

If you want tags to be saved parametrized (you can redefine to_param as well):

  ActsAsTaggableOn.force_parameterize = true


== Contributors

We have a long list of valued contributors. {Check them all}[https://github.com/mbleigh/acts-as-taggable-on/contributors]

== Maintainers

* Artem Kramarenko (artemk)

== Author

* Michael Bleigh

Copyright (c) 2007-2011 Michael Bleigh (http://mbleigh.com/) and Intridea Inc. (http://intridea.com/), released under the MIT license