RelationToJSON

RelationToJSON allows the conversion of ActiveRecord::Relation objects into an array of hash-like objects, provided a schema. It allows nesting across different relations, and uses pluck to optimize queries over multiple tables. This also acts as a useful interface in a React on Rails application where data needs to be passed to the front end in a simple serializable object, rather than passing a Rails object.

Add this line to your application's Gemfile

gem 'relation_to_json'

And then execute:

$ bundle install

Or install it yourself as:

$ gem install relation_to_json

A schema is an array of attributes that you would like your resultant JSON object to have.

class User < ApplicationRecord
  has_one :keyboard
  validate :first_name, :last_name, presence: true
end

class Keyboard < ApplicationRecord
  belongs_to :user
  validate :make, :model, presence: true
end

You can write the following schema:

[
  :first_name,
  :last_name,
  keyboard: [
    :make,
    :model,
  ]
]

Thus with the following ActiveRecord::Relation, such as User.all, we can write out the following:

User.all.to_json_with_schema(schema)

Assuming that all of the relations exist, we can expect a response of the format:

[
  {
    id: 1,
    first_name: ...,
    last_name: ...,
    keyboard: {
      make: ...,
      model: ...,
    }
  },
  {
    id: 2,
    first_name: ...,
    last_name: ...,
    keyboard: {
      make: ...,
      model: ...,
    }
  }
]

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 the created tag, and push the .gem file to rubygems.org.

Bug reports and pull requests are welcome on Github at https://github.com/DerekYu177/relation_to_json.

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