Dry::Params

Dry::Params brings all features of dry-validation into your Rails controller and provides an API to validate request parameters with Dry::Validation

Installation

Add this line to your application's Gemfile:

gem 'dry-params', github: 'kirs/dry-params'

Then add dry-params helper to your controller:

# app/controllers/application_controller
class ApplicationController < ActionController::Base
  # ...
  include Dry::Params::ActionControllerHelper
end

Usage

Describe request parameters validation rules in controller just like with Strong Parameters:

# app/schemas/user_signup_schema.rb
class UserSignupSchema < Dry::Validation::Schema::Form
  key(:name) { |f| f.filled? } # key should be present
  key(:age) { |f| f.int? } # should be an integer
  key(:account_id) { |f| f.int? }
  key(:group_ids) { |f| f.array? do # should be an array of integers
    v.each(&:int?)
  end
end

class UsersController < ApplicationController
  def user_params
    dry_params.fetch(:user).validate(UserSignupSchema)
  end
end

These rules describe a hash:

{
  "users" =>
    {
      "name" => "Kir",
      "age" => "21",
      "account_id" => "1",
      "group_ids" => ["1", "3", "5"]
    }
}

Dry::Params#validate will return the following type-coerced and validated hash:

{
  name: "Kir",
  age: 21,
  account_id: 1,
  group_ids: [1, 3, 5]
}

Strict validation

This is a default validation mode. It checks request params to strictly satisfy dry-validation rules. If params do not satisfy, Dry::Params::ValidationError will be raised.

Filter validation

Filter validation returns hash with only keys that pass validation rules.

def user_params
  dry_params.fetch(:user).validate(UserSignupSchema, mode: :filter)
end

If user passes the following request parameters:

{
  "users" =>
    {
      "name" => "Kir",
      "age" => "not-an-age",
      "account_id" => "fff",
      "group_ids" => "not-an-array"
    }
}

user_params will return a hash with only one valid key: name.

{
  name: "Kir"
}

Development

After checking out the repo, run bin/setup to install dependencies. Then, run rake test 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/[USERNAME]/dry-params.

License

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