ActiveRecord::JSONValidator

ActiveRecord::JSONValidator makes it easy to validate JSON attributes against a JSON schema.

Installation

Add this line to your application's Gemfile:

gem 'activerecord_json_validator'

Usage

JSON Schema

{
  "type": "object",
  "$schema": "http://json-schema.org/draft-03/schema",
  "properties": {
    "city": { "type": "string", "required": false },
    "country": { "type": "string", "required": true }
  }
}

Ruby

create_table "users" do |t|
  t.string "name"
  t.json "profile" # First-class JSON with PostgreSQL, yo.
end

class User < ActiveRecord::Base
  # Constants
  PROFILE_JSON_SCHEMA = Rails.root.join('config', 'schemas', 'profile.json_schema').to_s

  # Validations
  validates :name, presence: true
  validates :profile, presence: true, json: { schema: PROFILE_JSON_SCHEMA }
end

user = User.new(name: 'Samuel Garneau', profile: { city: 'Quebec City' })
user.valid? # => false

user = User.new(name: 'Samuel Garneau', profile: { city: 'Quebec City', country: 'Canada' })
user.valid? # => true

user = User.new(name: 'Samuel Garneau', profile: '{invalid JSON":}')
user.valid? # => false
user.profile_invalid_json # => '{invalid JSON":}'

Options

Option	Description
:schema	The JSON schema to validate the data against (see JSON schema option section)
:message	The ActiveRecord message added to the record errors (default: :invalid_json)

JSON schema option

You can specify four kinds of value for the :schema option.

A path to a file containing a JSON schema

class User < ActiveRecord::Base
  # Constants
  PROFILE_JSON_SCHEMA = Rails.root.join('config', 'schemas', 'profile.json_schema').to_s

  # Validations
  validates :profile, presence: true, json: { schema: PROFILE_JSON_SCHEMA }
end

A Ruby Hash representing a JSON schema

class User < ActiveRecord::Base
  # Constants
  PROFILE_JSON_SCHEMA = {
    type: 'object',
    :'$schema' => 'http://json-schema.org/draft-03/schema',
    properties: {
      city: { type: 'string', required: false },
      country: { type: 'string', required: true }
    }
  }

  # Validations
  validates :profile, presence: true, json: { schema: PROFILE_JSON_SCHEMA }
end

A plain JSON schema as a Ruby String

class User < ActiveRecord::Base
  # Constants
  PROFILE_JSON_SCHEMA = '{
    "type": "object",
    "$schema": "http://json-schema.org/draft-03/schema",
    "properties": {
      "city": { "type": "string", "required": false },
      "country": { "type": "string", "required": true }
    }
  }'

  # Validations
  validates :profile, presence: true, json: { schema: PROFILE_JSON_SCHEMA }
end

A lambda that will get evaluated in the context of the validated record

The lambda must return a valid value for the :schema option (file path, JSON String or Ruby Hash).

class User < ActiveRecord::Base
  # Constants
  PROFILE_REGULAR_JSON_SCHEMA = Rails.root.join('config', 'schemas', 'profile.json_schema').to_s
  PROFILE_ADMIN_JSON_SCHEMA = Rails.root.join('config', 'schemas', 'profile_admin.json_schema').to_s

  # Validations
  validates :profile, presence: true, json: { schema: lambda { dynamic_profile_schema } }

  def dynamic_profile_schema
    admin? ? PROFILE_ADMIN_JSON_SCHEMA : PROFILE_REGULAR_JSON_SCHEMA
  end
end

License

ActiveRecord::JSONValidator is © 2013-2015 Mirego and may be freely distributed under the New BSD license. See the LICENSE.md file.

About Mirego

Mirego is a team of passionate people who believe that work is a place where you can innovate and have fun. We're a team of talented people who imagine and build beautiful Web and mobile applications. We come together to share ideas and change the world.

We also love open-source software and we try to give back to the community as much as we can.