Gate

Gate is a small wrapper on dry-validation that might be used as Command in CQRS pattern or replace Strong Params in Ruby on Rails applications.

Gate::Command will raise InvalidCommand error for invalid input and provide simple struct with access to coerced input.

Installation

Add this line to your application's Gemfile:

gem 'gate'

And then execute:

$ bundle

Or install it yourself as:

$ gem install gate

Command Usage

Define structure

class DoSomethingCommand
  include Gate::Command

  schema do
    required(:id).filled
    required(:message).schema do
      required(:title).filled
      optional(:value).maybe(:decimal?)
    end
  end
end

Use it

begin
  cmd = DoSomethingCommand.with(params)
  cmd.id
  cmd.message
rescue DoSomethingCommand::InvalidCommand => e
  e.errors # => hash { key => [errors] }
end

Rails Usage

Define schemas per action

class ExampleController < ActionController::Base
  include Gate::Rails

  before_action :validate_params, if: { |c| c.params_schema_registered? }

  # Define schema just before action method
  def_schema do
    required(:id).filled
    required(:message).schema do
      required(:title).filled
      optional(:value).maybe(:decimal?)
    end
  end

  def foo
    # you can access Dry::Validation result with:
    validated_params
  end

  # default handler for invalid params which you can override
  def handle_invalid_params(_errors)
    # errors is Dry::Validation messages hash

    head :bad_request
  end
end

Configuration

Gate gives a possibility to create global, inherited configuration and separated setup in each one schema definition.

Inheriting base setup

In order to configure the library according to the whole application, create a file under config/initializers/gate.rb. There is a possibility of creating a base configuration, defining shared, custom predicates and a lot more useful things. The full list of supported configuration options is consistent with available options in dry-validation gem.

Gate::Rails.configure do
  configure do |config|
    config.messages_file = Rails.root.join("config", "locales" "en.yml")

    predicates(SharedPredicates)

    def foo?(value)
      value == "FOO"
    end
  end
end

Separated setup

Sometimes there is a requirement to have a very specific configuration or behaviour in a one schema validation. The easiest way is to do it in a special configure block.

class DoSomethingCommand
  include Gate::Command

  schema do
    configure do
      config.messages_file = Rails.root.join("config", "locales" "special_en.yml")
      predicates(SharedPredicates)
    end
    required(:id).filled
    required(:message).schema do
      required(:title).filled
      optional(:value).maybe(:decimal?)
    end
  end
end

Development

After checking out the repo, run bin/setup to install dependencies. Then, 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 to create a git tag for the version, push git commits and tags, and push the .gem file to rubygems.org.

Contributing

1. Fork it ( https://github.com/[my-github-username]/gate/fork )
2. Create your feature branch (git checkout -b my-new-feature)
3. Commit your changes (git commit -am 'Add some feature')
4. Push to the branch (git push origin my-new-feature)
5. Create a new Pull Request