CODEWITHSUNDEEP
ruby-on-railsactiverecordruby-on-rails-plugins
BuddyJoe
BuddyJoe

Reputation: 71101

acts-as-taggable-on - How do you get Tags by Parent object

If I have two models Buckets and Photos. Buckets has_many Photos and Photo belongs_to a Bucket. If I then added tagging to photos using the acts-as-taggable-on gem. What is the best way (idiomatic and performs well) to get a unique list of tags by Bucket? or for a single Bucket?

Upvotes: 0

Views: 403

Answers (1)

Fabio
Fabio

Reputation: 19176

Something like this should meet your request

# in your bucket class
def tag_list
  photos.inject([]) do |tags, photo|
    # with inject syntax
    tags + photo.tags.map(&:name) # remove the maps call if you need tag objects
  end.uniq
end

def alternative_tag_list
  # this code is even simpler, return unique tags
  photos.map { |p| p.tags }.flatten.uniq
end

You should benchmark them. They should perform well with a few data and you can always use memoization or cache for the result. You can reduce the number of queries needed by fetching your bucket object including both photos and tags with includes() as in

@bucket = Bucket.includes(:photos).includes(:tags).find(params[:id])

If the benchmark is not good you should go with SQL, but then you're going to loose syntactic sugar of inject & co.

Upvotes: 1

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