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.

Add this line to your application's Gemfile:

gem 'param_check'

And then execute:

$ bundle

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

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'

For number validation, you can use either the long hand keys less_than or the short hand lt

def index
  param! :foo, lt: 2
  param! :bar, lte: 3
  param! :baz, mt: 4
  param! :bazzy, mte: 5
end

def index
  param! :foo, in: ['foo', 'bar']
  param! :bar, in: 1..4
  param! :baz, in: 'a'..'z'
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

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Givey

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.

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.

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