Module: FuzzySearch::TrigramModelExtensions

Defined in:
lib/trigram_model_extensions.rb

Instance Method Summary collapse

Instance Method Details

#delete_trigrams(rec) ⇒ Object 



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# File 'lib/trigram_model_extensions.rb', line 86

def delete_trigrams(rec)
  delete_all(:rec_id => rec.id)
end

#params_for_search(search_term, opts = {}) ⇒ Object 



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# File 'lib/trigram_model_extensions.rb', line 18

def params_for_search(search_term, opts = {})
  trigrams = FuzzySearch::split_trigrams(search_term)
  # No results for empty search string
  return {:conditions => "0 = 1"} unless trigrams and !trigrams.empty?

  subset = nil
  if opts[:subset]
    if (
    opts[:subset].size == 1 &&
    opts[:subset].keys.first == target_class.fuzzy_search_subset_property
    )
      subset = opts[:subset].values.first.to_i
      opts.delete(:subset)
    else
      # TODO Test me
      raise "Invalid subset argument #{opts[:subset]}"
    end
  end

  unless opts.empty?
    # TODO Test me
    raise "Invalid options: #{opts.keys.join(",")}"
  end

  # Retrieve the IDs of the matching items
  search_result = connection.select_rows(
    "SELECT rec_id, count(*) FROM #{i(table_name)} " +
    (connection.adapter_name.downcase == 'mysql' ?
      "IGNORE INDEX (index_#{table_name}_on_rec_id) " : ""
    ) +
    "WHERE token IN (#{trigrams.map{|t| v(t)}.join(',')}) " +
    (subset ? "AND subset = #{subset} " : "") +
    "GROUP by rec_id " +
    "ORDER BY count(*) DESC " +
    "LIMIT #{target_class.send(:fuzzy_search_limit)}"
  )
  return {:conditions => "0 = 1"} if search_result.empty?

  # Perform a join between the target table and a fake table of matching ids
  static_sql_union = search_result.map{|rec_id, count|
    "SELECT #{v(rec_id)} AS id, #{count} AS score"
  }.join(" UNION ");
  primary_key_expr = "#{i(target_class.table_name)}.#{i(target_class.primary_key)}"
  return {
    :joins => "INNER JOIN (#{static_sql_union}) AS fuzzy_search_results ON " +
              "fuzzy_search_results.id = #{primary_key_expr}",
    :order => "fuzzy_search_results.score DESC"
  }
end

#rebuild_index ⇒ Object 



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# File 'lib/trigram_model_extensions.rb', line 8

def rebuild_index
  reset_column_information
  delete_all
  target_class.find_each do |rec|
    # Maybe can make this more efficient by updating trigrams for
    # batches of records...
    update_trigrams(rec)
  end
end

#set_target_class(cls) ⇒ Object 



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# File 'lib/trigram_model_extensions.rb', line 3

def set_target_class(cls)
  write_inheritable_attribute :target_class, cls
  class_inheritable_reader :target_class
end

#update_trigrams(rec) ⇒ Object 



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# File 'lib/trigram_model_extensions.rb', line 68

def update_trigrams(rec)
  delete_trigrams(rec)

  values = target_class.fuzzy_search_properties.map{|p| rec.send(p)}
  values = values.select{|p| p and p.respond_to?(:to_s)}
  trigrams = FuzzySearch::split_trigrams(values)

  subset_prop = target_class.fuzzy_search_subset_property
  subset = subset_prop ? rec.send(subset_prop) : 0

  # Ar-extensions import, much much faster than individual creates
  import(
    [:subset, :token, :rec_id],
    trigrams.map{|t| [subset, t, rec.id]},
    :validate => false
  )
end