Awesome
Metka
Rails gem to manage tags with PostgreSQL array columns.
:exclamation: Requirements:
- Ruby ~> 2.5
- Rails >= 5.2 (for Rails 5.1 and 5.0 use version <2.1.0)
Installation
Add this line to your application's Gemfile:
gem 'metka'
And then execute:
bundle
Or install it yourself as:
gem install metka
Tag objects
rails g migration CreateSongs
class CreateSongs < ActiveRecord::Migration[5.0]
def change
create_table :songs do |t|
t.string :title
t.string :tags, array: true, default: [], index: { using: :gin }
t.string :genres, array: true, default: [], index: { using: :gin }
t.timestamps
end
end
end
class Song < ActiveRecord::Base
include Metka::Model(columns: %w[genres tags])
end
@song = Song.new(title: 'Migrate tags in Rails to PostgreSQL')
@song.tag_list = 'top, chill'
@song.genre_list = 'rock, jazz, pop'
@song.save
Find tagged objects
.with_all_#{column_name}
Song.with_all_tags('top')
#=> [#<Song id: 1, title: 'Migrate tags in Rails to PostgreSQL', tags: ['top', 'chill'], genres: ['rock', 'jazz', 'pop']]
Song.with_all_tags('top, 1990')
#=> []
Song.with_all_tags('')
#=> [#<Song id: 1, title: 'Migrate tags in Rails to PostgreSQL', tags: ['top', 'chill'], genres: ['rock', 'jazz', 'pop']]
Song.with_all_tags(nil)
#=> [#<Song id: 1, title: 'Migrate tags in Rails to PostgreSQL', tags: ['top', 'chill'], genres: ['rock', 'jazz', 'pop']]
Song.with_all_genres('rock')
#=> [#<Song id: 1, title: 'Migrate tags in Rails to PostgreSQL', tags: ['top', 'chill'], genres: ['rock', 'jazz', 'pop']]
.with_any_#{column_name}
Song.with_any_tags('chill')
#=> [#<Song id: 1, title: 'Migrate tags in Rails to PostgreSQL', tags: ['top', 'chill'], genres: ['rock', 'jazz', 'pop']]
Song.with_any_tags('chill, 1980')
#=> [#<Song id: 1, title: 'Migrate tags in Rails to PostgreSQL', tags: ['top', 'chill'], genres: ['rock', 'jazz', 'pop']]
Song.with_any_tags('')
#=> [#<Song id: 1, title: 'Migrate tags in Rails to PostgreSQL', tags: ['top', 'chill'], genres: ['rock', 'jazz', 'pop']]
Song.with_any_tags(nil)
#=> [#<Song id: 1, title: 'Migrate tags in Rails to PostgreSQL', tags: ['top', 'chill'], genres: ['rock', 'jazz', 'pop']]
Song.with_any_genres('rock, rap')
#=> [#<Song id: 1, title: 'Migrate tags in Rails to PostgreSQL', tags: ['top', 'chill'], genres: ['rock', 'jazz', 'pop']]
.without_all_#{column_name}
Song.without_all_tags('top')
#=> []
Song.without_all_tags('top, 1990')
#=> [#<Song id: 1, title: 'Migrate tags in Rails to PostgreSQL', tags: ['top', 'chill'], genres: ['rock', 'jazz', 'pop']]
Song.without_all_tags('')
#=> [#<Song id: 1, title: 'Migrate tags in Rails to PostgreSQL', tags: ['top', 'chill'], genres: ['rock', 'jazz', 'pop']]
Song.without_all_tags(nil)
#=> [#<Song id: 1, title: 'Migrate tags in Rails to PostgreSQL', tags: ['top', 'chill'], genres: ['rock', 'jazz', 'pop']]
Song.without_all_genres('rock, pop')
#=> [#<Song id: 1, title: 'Migrate tags in Rails to PostgreSQL', tags: ['top', 'chill'], genres: ['rock', 'jazz', 'pop']]
Song.without_all_genres('rock')
#=> []
.without_any_#{column_name}
Song.without_any_tags('top, 1990')
#=> []
Song.without_any_tags('1990, 1980')
#=> [#<Song id: 1, title: 'Migrate tags in Rails to PostgreSQL', tags: ['top', 'chill'], genres: ['rock', 'jazz', 'pop']]
Song.without_any_genres('rock, pop')
#=> []
Song.without_any_genres('')
#=> [#<Song id: 1, title: 'Migrate tags in Rails to PostgreSQL', tags: ['top', 'chill'], genres: ['rock', 'jazz', 'pop']]
Song.without_any_genres(nil)
#=> [#<Song id: 1, title: 'Migrate tags in Rails to PostgreSQL', tags: ['top', 'chill'], genres: ['rock', 'jazz', 'pop']]
.tagged_with
Song.tagged_with('top')
#=> [#<Song id: 1, title: 'Migrate tags in Rails to PostgreSQL', tags: ['top', 'chill'], genres: ['rock', 'jazz', 'pop']]
Song.tagged_with('top, 1990')
#=> []
Song.tagged_with('')
#=> [#<Song id: 1, title: 'Migrate tags in Rails to PostgreSQL', tags: ['top', 'chill'], genres: ['rock', 'jazz', 'pop']]
Song.tagged_with(nil)
#=> [#<Song id: 1, title: 'Migrate tags in Rails to PostgreSQL', tags: ['top', 'chill'], genres: ['rock', 'jazz', 'pop']]
Song.tagged_with('rock')
#=> [#<Song id: 1, title: 'Migrate tags in Rails to PostgreSQL', tags: ['top', 'chill'], genres: ['rock', 'jazz', 'pop']]
Song.tagged_with('rock', join_operator: Metka::And)
#=> []
Song.tagged_with('chill', any: true)
#=> [#<Song id: 1, title: 'Migrate tags in Rails to PostgreSQL', tags: ['top', 'chill'], genres: ['rock', 'jazz', 'pop']]
Song.tagged_with('chill, 1980', any: true)
#=> [#<Song id: 1, title: 'Migrate tags in Rails to PostgreSQL', tags: ['top', 'chill'], genres: ['rock', 'jazz', 'pop']]
Song.tagged_with('', any: true)
#=> [#<Song id: 1, title: 'Migrate tags in Rails to PostgreSQL', tags: ['top', 'chill'], genres: ['rock', 'jazz', 'pop']]
Song.tagged_with('rock, rap', any: true, on: ['genres'])
#=> [#<Song id: 1, title: 'Migrate tags in Rails to PostgreSQL', tags: ['top', 'chill'], genres: ['rock', 'jazz', 'pop']]
Song.without_all_tags('top')
#=> []
Song.tagged_with('top, 1990', exclude: true)
#=> [#<Song id: 1, title: 'Migrate tags in Rails to PostgreSQL', tags: ['top', 'chill'], genres: ['rock', 'jazz', 'pop']]
Song.tagged_with('', exclude: true)
#=> [#<Song id: 1, title: 'Migrate tags in Rails to PostgreSQL', tags: ['top', 'chill'], genres: ['rock', 'jazz', 'pop']]
Song.tagged_with('top, 1990', any: true, exclude: true)
#=> []
Song.tagged_with('1990, 1980', any: true, exclude: true)
#=> [#<Song id: 1, title: 'Migrate tags in Rails to PostgreSQL', tags: ['top', 'chill'], genres: ['rock', 'jazz', 'pop']]
Song.without_any_genres('rock, pop')
#=> []
Custom delimiter
By default, a comma is used as a delimiter to create tags from a string. You can make your own custom separator:
Metka.config.delimiter = '|'
parsed_data = Metka::GenericParser.instance.call('cool, data|I have')
parsed_data.to_a
#=>['cool, data', 'I have']
Tags with quote
parsed_data = Metka::GenericParser.instance.call("'cool, data', code")
parsed_data.to_a
#=> ['cool, data', 'code']
Custom parser
By default we use generic_parser If you want to use your custom parser you can do:
class Song < ActiveRecord::Base
include Metka::Model(columns: %w[genres tags], parser: Your::Custom::Parser.instance)
end
Custom parser must be a singleton class that has a .call method that accepts the tag string
Tag Cloud Strategies
There are several strategies to get tag statistics
ActiveRecord Strategy (Default)
Data about taggings is accessible via class methods of your model with Metka::Model attached. You can calculate a cloud for a single tagged column or multiple columns, the latter case would return to you a sum of taggings from multiple tagged columns, that are provided as arguments, for each tag present. ActiveRecord Strategy is an easiest way to implement, since it wouldn't require any additional code, but it's the slowest one on SELECT.
class Book < ActiveRecord::Base
include Metka::Model(column: 'authors')
include Metka::Model(column: 'co_authors')
end
tag_cloud = Book.author_cloud
#=> [["L.N. Tolstoy", 3], ["F.M. Dostoevsky", 6]]
genre_cloud = Book.co_author_cloud
#=> [["A.P. Chekhov", 5], ["N.V. Gogol", 8], ["L.N. Tolstoy", 2]]
summary_cloud = Book.metka_cloud('authors', 'co_authors')
#=> [["L.N. Tolstoy", 5], ["F.M. Dostoevsky", 6], ["A.P. Chekhov", 5], ["N.V. Gogol", 8]]
View Strategy
Data about taggings will be aggregated in SQL View. Performance-wise that strategy has no benefits over ActiveRecord Strategy, but if you need to store tags aggregations in a distinct model, that's an easiest way to achieve it.
rails g metka:strategies:view --source-table-name=NAME_OF_TABLE_WITH_TAGS [--source-columns=NAME_OF_COLUMN_1 NAME_OF_COLUMN_2] [--view-name=NAME_OF_RESULTING_VIEW]
The code above will generate a migration that creates view with specified NAME_OF_RESULTING_VIEW, that would aggregate tags data from specified array of tagged columns [NAME_OF_COLUMN_1, NAME_OF_COLUMN_2, ...], that are present within specified table NAME_OF_TABLE_WITH_TAGS.
If source-columns option is not provided, then tags column would be used as defaults. If array of multiple values would be provided to the option, then the aggregation would be made with the tags from multiple tagged columns, so if a single tag would be found within multiple tagged columns, the resulting aggregation inside the view would have a single row for that tag with a sum of it's occurrences across all stated tagged columns.
view-name option is also optional, it would just force the resulting view's name to the one of your choice. If it's not provided, then view name would be generated automatically, you could check it within generated migration.
Lets take a look at real example. We have a notes table with tags column.
| Column | Type | Default |
|---|---|---|
| id | integer | nextval('notes_id_seq'::regclass) |
| body | text | |
| tags | character varying[] | '{}'::character varying[] |
Now lets generate a migration.
rails g metka:strategies:view --source-table-name=notes
The result would be:
# frozen_string_literal: true
class CreateTaggedNotesView < ActiveRecord::Migration[5.0]
def up
execute <<-SQL
CREATE OR REPLACE VIEW tagged_notes AS
SELECT
tag_name,
COUNT ( * ) AS taggings_count
FROM (
SELECT UNNEST
( tags ) AS tag_name
FROM
view_posts
) subquery
GROUP BY
tag_name;
SQL
end
def down
execute <<-SQL
DROP VIEW tagged_notes;
SQL
end
end
Now lets take a look at tagged_notes view.
| tag_name | taggings_count |
|---|---|
| Ruby | 124056 |
| React | 30632 |
| Rails | 28696 |
| Crystal | 6566 |
| Elixir | 3475 |
Now you can create TaggedNote model and work with the view like you usually do with Rails models.
Materialized View Strategy
Data about taggings will be aggregated in SQL Materialized View, that would be refreshed with the trigger on each change of the tagged column's data. Except for the another type of view being used, that strategy behaves the same way, as a View Strategy above.
rails g metka:strategies:materialized_view --source-table-name=NAME_OF_TABLE_WITH_TAGS --source-columns=NAME_OF_COLUMN_1 NAME_OF_COLUMN_2 --view-name=NAME_OF_RESULTING_VIEW
All of the options for that strategy's generation command are the same as for the View Strategy.
The migration template can be seen here
With the same notes table with tags column the resulting view would have the same two columns
| tag_name | taggings_count |
|---|---|
| Ruby | 124056 |
| React | 30632 |
| Rails | 28696 |
| Crystal | 6566 |
| Elixir | 3475 |
And you can also create TaggedNote model to work with the view as with a Rails model.
Table Strategy with Triggers
TBD
Inspired by
Migration from ActsAsTaggable
To migrate your data from ActsAsTaggable can be done with the following migration.
class AddTagsToYourTable < ActiveRecord::Migration[6.0]
def change
add_column :your_table, :tags, :string, array: true
add_index :your_table, :tags, using: 'gin'
execute <<~SQL
UPDATE your_table
SET tags = tags.names
FROM (
SELECT taggings.taggable_id AS your_table_id,
array_agg(tags.name) as names
FROM tags
INNER JOIN taggings
ON tags.id = taggings.tag_id
WHERE
taggings.taggable_type = 'YouTableType'
GROUP BY taggings.taggable_id
) as tags
WHERE your_table.id = tags.your_table_id
SQL
end
end
Benchmark Comparison
There are some results of benchmarking a performance of write, read and find operations for different gems, that provide solution for tagging. Keep in mind, that those results can't be used as a proof, that some solution is better than the others, since each of the benchmarked gems has their unique features. You could run the benchmarks yourself or check, what exact operations has been used for benchmarking, with MetkaBench application.
$ rake bench:all
Deleted all MetkaSong
Deleted all ActsAsTaggableOn::Tagging
Deleted all ActsAsTaggableOn::Tag
Deleted all ActsAsTaggableSong
Deleted all ActsAsTaggableArraySong
Deleted all TagColumnsSong
Finished to clean
###################################################################
bench:write
Time measurements:
Rehearsal ----------------------------------------------------------
Metka: 2.192410 0.161092 2.353502 ( 2.754766)
ActsAsTaggableOn: 13.769918 0.554951 14.324869 ( 16.990127)
ActsAsTaggableOnArray: 2.150441 0.154127 2.304568 ( 2.700022)
TagColumns: 2.202647 0.156162 2.358809 ( 2.753400)
------------------------------------------------ total: 21.341748sec
user system total real
Metka: 2.137315 0.154046 2.291361 ( 2.643363)
ActsAsTaggableOn: 11.302848 0.448674 11.751522 ( 14.019458)
ActsAsTaggableOnArray: 2.143134 0.128655 2.271789 ( 2.670797)
TagColumns: 2.133780 0.125749 2.259529 ( 2.653404)
Memory measurements:
Calculating -------------------------------------
Metka: 179.064M memsize ( 0.000 retained)
1.689M objects ( 0.000 retained)
50.000 strings ( 0.000 retained)
ActsAsTaggableOn: 843.949M memsize ( 0.000 retained)
8.550M objects ( 0.000 retained)
50.000 strings ( 0.000 retained)
ActsAsTaggableOnArray: 178.807M memsize ( 0.000 retained)
1.684M objects ( 0.000 retained)
50.000 strings ( 0.000 retained)
TagColumns: 180.009M memsize ( 0.000 retained)
1.699M objects ( 0.000 retained)
50.000 strings ( 0.000 retained)
###################################################################
bench:read
Time measurements:
Rehearsal ----------------------------------------------------------
Metka: 0.479695 0.044399 0.524094 ( 0.590616)
ActsAsTaggableOn: 2.436328 0.140581 2.576909 ( 3.096142)
ActsAsTaggableOnArray: 0.515198 0.042127 0.557325 ( 0.623205)
TagColumns: 0.518363 0.042661 0.561024 ( 0.626968)
------------------------------------------------- total: 4.219352sec
user system total real
Metka: 0.446751 0.041886 0.488637 ( 0.554018)
ActsAsTaggableOn: 2.395166 0.164500 2.559666 ( 3.069655)
ActsAsTaggableOnArray: 0.439608 0.041682 0.481290 ( 0.544679)
TagColumns: 0.435404 0.041623 0.477027 ( 0.540359)
Memory measurements:
Calculating -------------------------------------
Metka: 42.291M memsize ( 0.000 retained)
388.694k objects ( 0.000 retained)
50.000 strings ( 0.000 retained)
ActsAsTaggableOn: 178.664M memsize ( 0.000 retained)
1.812M objects ( 0.000 retained)
50.000 strings ( 0.000 retained)
ActsAsTaggableOnArray: 42.173M memsize ( 0.000 retained)
383.003k objects ( 0.000 retained)
50.000 strings ( 0.000 retained)
TagColumns: 41.948M memsize ( 0.000 retained)
383.003k objects ( 0.000 retained)
50.000 strings ( 0.000 retained)
###################################################################
bench:find_by_tag
Time measurements:
Rehearsal ----------------------------------------------------------
Metka: 0.029961 0.000059 0.030020 ( 0.030052)
ActsAsTaggableOn: 0.067095 0.000068 0.067163 ( 0.067205)
ActsAsTaggableOnArray: 0.043156 0.000133 0.043289 ( 0.043440)
TagColumns: 0.056475 0.000143 0.056618 ( 0.056697)
------------------------------------------------- total: 0.197090sec
user system total real
Metka: 0.028291 0.000019 0.028310 ( 0.028321)
ActsAsTaggableOn: 0.065925 0.000036 0.065961 ( 0.065989)
ActsAsTaggableOnArray: 0.043214 0.000079 0.043293 ( 0.043361)
TagColumns: 0.056390 0.000160 0.056550 ( 0.056666)
Memory measurements:
Calculating -------------------------------------
Metka: 4.752M memsize ( 0.000 retained)
43.000k objects ( 0.000 retained)
1.000 strings ( 0.000 retained)
ActsAsTaggableOn: 8.967M memsize ( 0.000 retained)
81.002k objects ( 0.000 retained)
9.000 strings ( 0.000 retained)
ActsAsTaggableOnArray: 5.211M memsize ( 0.000 retained)
57.003k objects ( 0.000 retained)
6.000 strings ( 0.000 retained)
TagColumns: 6.696M memsize ( 0.000 retained)
94.003k objects ( 0.000 retained)
8.000 strings ( 0.000 retained)
Finished all benchmarks
Development
After checking out the repo, run bin/setup to install dependencies. Then, run rake spec to run the tests. You can also run bin/console for an interactive prompt that will allow you to experiment.
To install this gem onto your local machine, run bundle exec rake install. To release a new version, update the version number in version.rb, and then run bundle exec rake release, which will create a git tag for the version, push git commits and tags, and push the .gem file to rubygems.org.
Contributing
Bug reports and pull requests are welcome on GitHub at https://github.com/jetrockets/metka. This project is intended to be a safe, welcoming space for collaboration, and contributors are expected to adhere to the Contributor Covenant code of conduct.
Credits
Metka is maintained by JetRockets.
License
The gem is available as open source under the terms of the MIT License.
Code of Conduct
Everyone interacting in the Metka project’s codebases, issue trackers, chat rooms and mailing lists is expected to follow the code of conduct.