ActiveTypedStore

active_typed_store is a lightweight (105 lines of code) and highly performant gem (see benchmarks) designed to help you store and manage typed data in JSON format within database. This gem provides a simple, yet powerful way to ensure that your JSON data cast to specific types, enabling more structured and reliable use of JSON fields in your Rails models.

You can use ActiveRecord Types for simplicity or Dry Types for more advanced features such as constraints and type composition. You can also combine both approaches in the same model to get the best of both worlds.

Installation

Add this line to your application's Gemfile:

gem "active_typed_store"

Usage

Using ActiveRecord Types

class Model < ActiveRecord::Base
  typed_store(:params) do # params - the name of the store
    attr :task_id,   :integer
    attr :name,      :string
    attr :notify_at, :datetime
    attr :asap,      :boolean, default: false
    attr :settings,  :json
  end
end

m = Model.first
m.task_id = "123" # string
m.task_id # => 123, int
m.task_id? # => true, value.present? under the hood
m.asap? # => false
m.asap = "yes"
m.asap # => true
m.asap? # => true

attr(name, type, options)

name the name of the accessor to the store
type a symbol such as :string or :integer, or a type object to be used for the accessor
options (optional), a hash of cast type options such as:
- precision, limit, scale
- default the default value to use when no value is provided. Otherwise, the default will be nil
- array specifies that the type should be an array

Using Dry Types

class Model < ActiveRecord::Base
  typed_store(:params) do
    attr :task_id,   Types::Params::Integer
    attr :name,      Types::Params::String
    attr :notify_at, Types::Params::Time
    attr :asap,      Types::Params::Bool.default(false)
    attr :email,     Types::String.constrained(format: /@/)
    attr :settings,  Types::Params::Hash
  end
end

Combine ActiveRecord and Dry Types

class Model < ActiveRecord::Base
  typed_store(:params) do
    attr :price,  :decimal, scale: 2
    attr :active, :immutable_string
    attr :email,  Types::String.constrained(format: /@/)
    attr :state,  Types::String.enum('draft', 'published', 'archived')
    attr :tariff_id, Types::Array.of(Types::Params::Integer)
  end
end

Hash safety

This gem assumes you're using a database that supports structured data types, such as json in PostgreSQL or MySQL, and leverages Rails' store_accessor under the hood. However, there’s one caveat: JSON columns use a string-keyed hash and don’t support access via symbols. To avoid unexpected errors when accessing the hash, we raise an error if a symbol is used. You can disable this behavior by setting config.hash_safety = false.

class Model < ActiveRecord::Base
  typed_store(:params) do
    attr :price,  :decimal
  end
end

record = Model.new(price: 1)
record["price"] # 1
record[:price] # raises "Symbol keys are not allowed `:price` (ActiveTypedStore::SymbolKeysDisallowed)"

# initializers/active_type_store.rb
ActiveTypeStore.configure do |config|
  config.hash_safety = false # default :disallow_symbol_keys
end

record["price"] # 1
record[:price] # nil - isn't the expected behavior for most applications

Benchmarks

compare active_typed_store with other gems

# ruby 3.3.5 arm64-darwin24
#                    gem     getter  i/s                setter i/s            Lines of code
#     active_typed_store:    28502.2                    656                   105
#  rails (without types):    27350.5                    660                   170
#        store_attribute:    24592.2 - 1.16x  slower    639                   276
#            store_model:    22833.6 - 1.25x  slower    595                   857
#              attr_json:    14000.4 - 2.03x  slower    577 - 1.14x  slower   1195
#         jsonb_accessor:    13995.4 - 2.04x  slower    626                   324

License

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