Module: RocketTag::Taggable::ClassMethods

Defined in:
lib/rocket_tag/taggable.rb

Instance Method Summary collapse

Instance Method Details

#attr_taggable(*contexts) ⇒ Object


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# File 'lib/rocket_tag/taggable.rb', line 316

def attr_taggable *contexts
  unless class_variable_defined?(:@@acts_as_rocket_tag)
    include RocketTag::Taggable::InstanceMethods
    class_variable_set(:@@acts_as_rocket_tag, true)
    alias_method_chain :reload, :tags
  end

  rocket_tag.contexts += contexts

  setup_for_rocket_tag

  contexts.each do |context|
    class_eval do

      has_many "#{context}_taggings".to_sym, 
        :source => :taggable,  
        :as => :taggable,
        :conditions => { :context => context }

      has_many "#{context}_tags".to_sym,
        :source => :tag,
        :through => :taggings,
        :conditions => [ "taggings.context = ?", context ]

      validate context do
        if not send(context).kind_of? Enumerable
          errors.add context, :invalid
        end
      end

      # This is to compensate for a rails bug that returns
      # a string for postgres
      def tags_count
        self[:tags_count].to_i
      end

      # Return an array of RocketTag::Tags for the context
      define_method "#{context}" do
        cache_tags
        tags_for_context(context)
      end

      define_method "#{context}=" do |list|
        list = Manager.parse_tags list

        # Ensure the tags are loaded
        cache_tags
        write_context(context, list)

        (@tag_dirty ||= Set.new) << context

      end
    end
  end
end

#is_valid_context?(context) ⇒ Boolean

Returns:

  • (Boolean)

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# File 'lib/rocket_tag/taggable.rb', line 128

def is_valid_context? context
    rocket_tag.contexts.include? context
end

#normalize_contexts(context, default_if_nil = []) ⇒ Object


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# File 'lib/rocket_tag/taggable.rb', line 132

def normalize_contexts(context, default_if_nil = [])
  contexts = if context
    if context.class == Array
      context
    else
      [context]
    end
  else
    default_if_nil
  end

  validate_contexts(contexts)

  contexts
end

Generates a query that returns list of popular tags for given model with an extra column :tags_count.


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# File 'lib/rocket_tag/taggable.rb', line 265

def popular_tags options={}
  tags(options)
end

#rocket_tagObject


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# File 'lib/rocket_tag/taggable.rb', line 124

def rocket_tag
  @rocket_tag ||= RocketTag::Taggable::Manager.new(self)
end

#setup_for_rocket_tagObject


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# File 'lib/rocket_tag/taggable.rb', line 269

def setup_for_rocket_tag
  unless @setup_for_rocket_tag
    @setup_for_rocket_tag = true
    class_eval do
      default_scope do
        preload{taggings}.preload{tags}
      end

      before_save do
        @tag_dirty ||= Set.new

        @tag_dirty.each do |context|
          # Get the current tags for this context
          list = send(context)

          # Destroy all taggings
          destroy_tags_for_context context

          # Find existing tags
          exisiting_tags = Tag.where{name.in(list)}
          exisiting_tag_names = exisiting_tags.map &:name

          # Find missing tags
          tags_names_to_create = list - exisiting_tag_names 

          # Create missing tags
          created_tags = tags_names_to_create.map do |tag_name|
            Tag.create :name => tag_name
          end

          # Recreate taggings
          tags_to_assign = exisiting_tags + created_tags

          tags_to_assign.each do |tag|
            tagging = Tagging.new :tag => tag, 
              :taggable => self, 
              :context => context, 
              :tagger => nil
            self.taggings << tagging
          end
        end
        @tag_dirty = Set.new
      end
    end
  end
end

#tagged_with(tags_list, options = {}) ⇒ Object


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# File 'lib/rocket_tag/taggable.rb', line 178

def tagged_with tags_list, options = {}

  # Grab table name
  t = self.table_name

  q = joins{taggings.tag}

  case tags_list
  when Hash
    # A tag can only match it's context

    c = tags_list.each_key.map do |context|
      squeel do
        tags.name.in(tags_list[context]) & (taggings.context == context.to_s)
      end
    end.inject do |s,t|
      s | t
    end

    q = q.where(c)

  else
    # Any tag can match any context
    q = q.
      where{tags.name.in(tags_list)}.
      where(with_tag_context(options.delete(:on)))
  end

  q = q.group_by_all_columns.
    select{count(tags.id).as( tags_count)}.
    select{"#{t}.*"}.
    order("tags_count desc")

  # Isolate the aggregate uery by wrapping it as
  #
  # select * from ( ..... ) tags
  q = from(q.arel.as(self.table_name))
  
  # Restrict by minimum tag counts if required
  min = options.delete :min 
  q = q.where{tags_count>=min} if min 

  # Require all the tags if required
  all = options.delete :all
  q = q.where{tags_count==tags_list.length} if all

  # Return the relation
  q
end

#tags(options = {}) ⇒ Object

Get the tags associated with this model class This can be chained such as

User.documents.tags


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# File 'lib/rocket_tag/taggable.rb', line 232

def tags(options = {})

  # Grab the current scope
  s = select{id}

  # Grab table name
  t = self.to_s

  q = RocketTag::Tag.joins{taggings}.
    where{taggings.taggable_type==t}.  # Apply taggable type
    where{taggings.taggable_id.in(s)}. # Apply current scope
    where(with_tag_context(options.delete(:on))). # Restrict by context
    group_by_all_columns.
    select{count(tags.id).as(tags_count)}.
    select('tags.*').
    order("tags_count desc")

  # Isolate the aggregate query by wrapping it as
  #
  # select * from ( ..... ) tags
  q = RocketTag::Tag.from(q.arel.as(RocketTag::Tag.table_name))
  
  # Restrict by minimum tag counts if required
  min = options.delete :min 
  q = q.where{tags_count>=min} if min 

  # Return the relation
  q

end

#validate_contexts(contexts) ⇒ Object

Verify contexts are valid for the taggable type


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# File 'lib/rocket_tag/taggable.rb', line 149

def validate_contexts contexts
  contexts.each do |context|
    unless is_valid_context? context
      raise Exception.new("#{context} is not a valid tag context for #{self}") 
    end
  end
end

#with_tag_context(context) ⇒ Object

Filters tags according to context. context param can be either a single context id or an array of context ids


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# File 'lib/rocket_tag/taggable.rb', line 161

def with_tag_context context
  contexts = normalize_contexts(context)

  condition = if contexts

    contexts.map do |context|
      squeel do
        (taggings.context == context.to_s)
      end
    end.inject do |s, t|
      s | t
    end

  end

end