Module: Glue::Taggable

Includes:
Og::EntityMixin
Defined in:
lib/glue/taggable.rb,
lib/glue/taggable_old.rb

Overview

Add tagging methods to the target class. For more information on the algorithms used surf: www.pui.ch/phred/archives/2005/04/tags-database-schemas.html

Example

class Article

  include Taggable
  ..
end

article.tag(‘navel’, ‘gmosx’, ‘nitro’) article.tags article.tag_names Article.find_with_tags(‘navel’, ‘gmosx’) Article.find_with_any_tag(‘name’, ‘gmosx’)

Article::Tag.find_by_name(‘ruby’).articles

Defined Under Namespace

Modules: ClassMethods

Class Method Summary collapse

Instance Method Summary collapse

Methods included from Og::EntityMixin

#assign_properties, #delete, #insert, #og_quote, #reload, #save, #saved?, #transaction, #update, #update_by_sql, #update_properties

Class Method Details

.append_dynamic_features(base, options = nil) ⇒ Object 



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# File 'lib/glue/taggable_old.rb', line 65

def self.append_dynamic_features(base, options = nil)
  o = { 
    :base_tag_class => Og::Tag,
    :separator => ' '
  }
  o.update(options) if options

  base.send :include, Og::RelationDSL

  code = ''
 
  unless o[:tag_class]
    o[:tag_class] = 'Tag'
    code << %{
      class #{o[:tag_class]} < #{o[:base_tag_class]}
        many_to_many #{base}, :foreign_name => :tags
      end
    }
  end
  
  tag_class = o[:tag_class]
  separator = o[:separator].inspect
  
  code << %{
    many_to_many :tags, #{o[:tag_class]}
   }

  # Instance Methods:
   
  # Apply a collection of tags to the object.
  # +tags+ can be either an array or a String.
  #
  # === Options
  #
  # +clear+: clear the tags collection before adding the
  #           new tags.

  code << %{      
    def tag(the_tags, options = {})
      return unless the_tags
      
      options = {
        :clear => true
      }.merge(options)
      
      names = Taggable.tags_to_names(the_tags, #{separator})
      
      tags.load_members
      
      # clear the collection if needed.    
      
      self.tags.clear if options[:clear]

      # append the tag names to the collection    
      
      names.each do |name| 
        name = name.strip
        unless tagged_with?(name)
          unless tag_obj = #{tag_class}.find_by_name(name) 
            tag_obj = #{tag_class}.create(name)
          end
           tags << tag_obj
         end
      end
      
      self.save
    end
  }

  # Clears all tags.
  
  def delete_tags
  end
  alias_method :clear_tags, :delete_tags
  
  # Returns an array of strings containing the tags applied to 
  # this object.
  
  code << %{  
    def tag_names
      tags.map { |t| t.name }
    end
  }  

  # Checks to see if this object has been tagged 
  # with +tag_name+.

  code << %{      
    def tagged_with?(tag_name)
      tag_names.include?(tag_name)
    end
    alias_method :tagged_by?, :tagged_with?      
  }

  # Class Methods:
  
  code << %{
    class << self
  }
  
  # Find objects with all of the provided tags.
  # INTERSECTION (AND)
  #--
  # TODO: move info out of compiled code.
  #++

  code << %{
    def find_with_tags(*names)
      info = ogmanager.store.join_table_info(#{base}, #{tag_class})
      count = names.size
      names = names.map { |n| "'\#{n}'" }.join(',')
      sql = %{        
        SELECT o.* 
        FROM 
          \#{info[:first_table]} AS o, 
          \#{info[:second_table]} as t, 
          \#{info[:table]} as j  
        WHERE o.oid = j.\#{info[:first_key]} 
          AND t.oid = j.\#{info[:second_key]} 
          AND (t.name in (\#{names}))
        GROUP BY o.oid
        HAVING COUNT(o.oid) = \#{count};
      }
      return self.select(sql)
    end
    alias_method :find_with_tag, :find_with_tags
  }

  # Find objects with any of the provided tags.
  # UNION (OR)

  code << %{
    def find_with_any_tag(*names)
      info = ogmanager.store.join_table_info(#{base}, #{tag_class})
      count = names.size
      names = names.map { |n| "'\#{n}'" }.join(',')
      sql = %{        
        SELECT o.* 
        FROM 
          \#{info[:first_table]} AS o, 
          \#{info[:second_table]} as t, 
          \#{info[:table]} as j  
        WHERE 
          o.oid = j.\#{info[:first_key]} 
          AND t.oid = j.\#{info[:second_key]} 
          AND (t.name in (\#{names}))
        GROUP BY o.oid
      }
      return self.select(sql)
    end
  }
      
  code << %{
    end
  }
  
  base.module_eval(code)
end

.included(base) ⇒ Object 



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# File 'lib/glue/taggable.rb', line 147

def self.included(base)
  Tag.module_eval do
    many_to_many base
  end
  base.extend(ClassMethods)
  #--
  # FIXME: Og should handle this automatically.
  #++
  base.send :include, Aspects
  base.before 'tags.clear', :on => [:og_delete]
end

.tags_to_names(the_tags, separator = ' ') ⇒ Object

Helper.



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

def self.tags_to_names(the_tags, separator = ' ')
  if the_tags.is_a? Array
    names = the_tags 
  elsif the_tags.is_a? String
    names = the_tags.split(separator)
  end
  
  names = names.flatten.uniq.compact
  
  return names
end

Instance Method Details

#delete_tags ⇒ Object

Clears all tags.



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# File 'lib/glue/taggable_old.rb', line 136

def delete_tags
end

#tag(the_tags, options = {}) ⇒ Object Also known as: tag!

Add a tag for this object.



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# File 'lib/glue/taggable.rb', line 73

def tag(the_tags, options = {})
  options = {
    :clear => true
  }.merge(options)
    
  self.tags.clear if options[:clear]
  
  for name in Taggable.tags_to_names(the_tags)
    Tag.find_or_create_by_name(name).tag(self)
  end    
end

#tag_names ⇒ Object

Return the names of the tags.



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# File 'lib/glue/taggable.rb', line 88

def tag_names
  tags.collect { |t| t.name }
end

#tagged_with?(tag_name) ⇒ Boolean Also known as: tagged_by?

Checks to see if this object has been tagged with tag_name.

Returns:

  • (Boolean) 


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# File 'lib/glue/taggable.rb', line 95

def tagged_with?(tag_name)
  tag_names.include?(tag_name)
end