PgFlashJson

Add this line to your application's Gemfile:

gem 'pg_flash_json'

And then execute:

$ bundle

Or install it yourself as:

$ gem install pg_flash_json

PGFlashJSON turns your ActiveRecord relations into json using the power of postgres' json support. It works by using the attributes of the model to build the proper postgres json query.

	class Post < ActiveRecord::Base
		# attributes :id, :title, :content
	end

	Post.where(id: 1).to_pg_json
		# SELECT json_agg(
		#	json_build_object(
		#		'id', t582.id,
		#		'title', t582.title,
		#		'content', t582.content
		#	))
		#	as json
		#   FROM(SELECT "posts".* FROM "posts" WHERE "posts"."id" = 1)t582

This query is run and the aliases in the above example will be generated on the fly to ensure uniqueness.

To use simply call #to_pg_json on any active record association.

Since the json is generated by postgres, we can skip object instantiation, accordingly PgFlashJson is faster when used to serialize a large number of records. Consider the following benchmarks. These ips benchmarks call the separate json methods on 100 Post models, each one has an id, title, and content. The json they produce is identical.

PgFlashJson#to_pg_json
                       179.000  i/100ms
ActiveRecord#to_json    20.000  i/100ms
-------------------------------------------------
PgFlashJson#to_pg_json
                          1.819k (± 3.9%) i/s -      9.129k
ActiveRecord#to_json    208.296  (± 4.3%) i/s -      1.040k

Comparison:
PgFlashJson#to_pg_json:     1819.5 i/s
ActiveRecord#to_json:      208.3 i/s - 8.73x slower

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. Additionally, the bin/benchmarks task will allow you to run the benchmarks locally.

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.

Bug reports and pull requests are welcome on GitHub at https://github.com/dandlezzz/pg_flash_json.

The gem is available as open source under the terms of the MIT License.