Module: Mongoid::Taggable::ClassMethods

Defined in:
lib/mongoid/taggable.rb

Instance Method Summary collapse

Instance Method Details

#aggregate_tags ⇒ Object

Execute map/reduce operation to aggregate tag counts for document class



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# File 'lib/mongoid/taggable.rb', line 102

def aggregate_tags
  return unless tag_aggregation

  map = "function() {
    if (!this.#{tags_field}) {
      return;
    }

    for (index in this.#{tags_field}) {
      emit(this.#{tags_field}[index], 1);
    }
  }"

  reduce = "function(previous, current) {
    var count = 0;

    for (index in current) {
      count += current[index]
    }

    return count;
  }"

  collection.master.map_reduce(map, reduce, :out => tags_aggregation_collection)
end

#taggable(*args) ⇒ Object

Macro to declare a document class as taggable, specify field name for tags, and set options for tagging behavior.

Examples:

Define a taggable document.


class Article
  include Mongoid::Document
  include Mongoid::Taggable
  taggable :keywords, :separator => ' ', :aggregation => true
end

Parameters:

  • field (Symbol) —

    The name of the field for tags.

  • options (Hash) —

    Options for taggable behavior.



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# File 'lib/mongoid/taggable.rb', line 50

def taggable(*args)
  options = args.extract_options!
  options.reverse_merge!(
    :separator => ',',
    :aggregation => false
  )

  write_inheritable_attribute(:tags_field, args.blank? ? :tags : args.shift)
  self.tags_separator  = options[:separator]
  self.tag_aggregation = options[:aggregation]

  field tags_field, :type => Array
  index tags_field

  define_tag_field_accessors(tags_field)
end

#tagged_with(_tags) ⇒ Criteria

Find documents tagged with all tags passed as a parameter, given as an Array or a String using the configured separator.

Examples:

Find matching all tags in an Array.

Article.tagged_with(['ruby', 'mongodb'])

Find matching all tags in a String.

Article.tagged_with('ruby, mongodb')

Parameters:

  • _tags (Array<String, Symbol>, String) —

    Tags to match.

Returns:

  • (Criteria) —

    A new criteria.



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# File 'lib/mongoid/taggable.rb', line 90

def tagged_with(_tags)
  _tags = convert_string_tags_to_array(_tags) if _tags.is_a? String
  criteria.all_in(tags_field => _tags)
end

#tags ⇒ Object

get an array with all defined tags for this model, this list returns an array of distinct ordered list of tags defined in all documents of this model



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# File 'lib/mongoid/taggable.rb', line 70

def tags
  db.collection(tags_aggregation_collection).find.to_a.map{ |r| r["_id"] }
end

#tags_aggregation_collection ⇒ Object

Collection name for storing results of tag count aggregation



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# File 'lib/mongoid/taggable.rb', line 96

def tags_aggregation_collection
  @tags_aggregation_collection ||= "#{collection_name}_tags_aggregation"
end

#tags_with_weight ⇒ Object

retrieve the list of tags with weight(count), this is useful for creating tag clouds



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# File 'lib/mongoid/taggable.rb', line 76

def tags_with_weight
  db.collection(tags_aggregation_collection).find.to_a.map{ |r| [r["_id"], r["value"]] }
end