ParamCheck

Easily validate params for API methods. Are you sick of writing respond_with(error) unless params[:foo].present?? With ParamCheck, you can abstract all of the validation.

Installation

Add this line to your application's Gemfile:

gem 'param_check'

And then execute:

$ bundle

Usage

Validating presence

By default, a parameter is not required unless you specify the required: true option

def index
  param! :foo, required: true
end

def index
  param! :foo, required: true do |foo| # params[foo]
    foo.param! :bar, required: true # params[foo][bar]
  end
end

Validating type

def index
  param! :foo, type: String
end

def index
  param! :foo, type: ActionController::Parameters do |foo|
    foo.param! :bar, type: Integer
    foo.param! :baz, type: String
  end
end

# Passes
params[:foo] = {
  bar: 1,
  baz: 'Two',
}

# Fails
params[:foo] = {
  bar: 'One',
  baz: 2,
}
params[:foo] = 'bar'

Validating range

def index
  param! :foo, min: 1, max: 3
end

Validating inclusion

def index
  param! :foo, in: ['foo', 'bar']
end

By default, ParamCheck throws a ParameterError exception. You can rescue from this exception in order to respond with JSON for example:

# in API::ApplicationController
rescue_from ParameterError do |e|
  render json: { error: e.message }
end

Options

Option	Type	Default	Values	Description
required	Boolean	false	true/false	Is the parameter required?
type	Class	nil	Fixnum/Integer/String/ActionController::Params	Specifies the type the parameter should be

Development

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 tags, and push the .gem file to rubygems.org.

Contributing

Bug reports and pull requests are welcome on GitHub at https://github.com/cjmarkham/param_check. This project is intended to be a safe, welcoming space for collaboration, and contributors are expected to adhere to the Contributor Covenant code of conduct.

License

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