ValidateParams

ValidateParams is a lightweight, robust Ruby on Rails gem that introduces a simple yet powerful DSL (Domain Specific Language) to validate and type cast the parameters for your controller actions. It is designed to make your code cleaner, more maintainable, and ensures that your application handles invalid or unexpected parameters gracefully.

Installation

Install the gem and add to the application's Gemfile by executing:

$ bundle add validate_params

If bundler is not being used to manage dependencies, install the gem by executing:

$ gem install validate_params

Usage

Definition of the validator with symbols as keys:

class TestController < ActionController::Base
  include ValidateParams::Validatable

  validate_params :index do |p|
    p.param :name, String, default: "John Doe"
    p.param :occurred_on, Date, required: true, default: proc { Date.today }
    p.param :per_page, Integer, default: 50, min: 1, max: 50
    p.param :quantity, Integer, required: true, in: [1, 2, 3]
    p.param :user_ids, Array, of: Integer, default: [1, 2, 3]
    p.param :states, Array, of: String, default: ["active", "inactive"], reject_blank: true
    p.param :file, IO, min: 1.byte, max: 1.megabyte
    p.param :date_of_birth, Hash do |pp|
      pp.param :gt, Date, min: Date.new(2020, 1, 1), max: Date.new(2021, 1, 1)
      pp.param :lt, Date
    end
    p.param :created_at, Hash do |pp|
      pp.param :lt, DateTime, min: DateTime.new(2020, 1, 1), max: DateTime.new(2021, 1, 1)
      pp.param :gt, DateTime
    end
  end

  def index
    ...
  end
end

Types

Here are the following supported types along with operations supported.

• String (required, default)
• Integer (required, default, min, max, in)
• Date (required, default, min, max)
• DateTime (required, default, min, max)
• IO (required, min, max)
• Array of: (String|Integer) (default, reject_blank)
• Hash - Nested block of types

Response

If the parameters are valid, the controller action will be executed as normal. If the parameters are invalid, a 400 Bad Request response will be returned with a JSON body containing the errors, or an empty HTML response.

JSON (Default)

{
    "success": false,
    "errors": [
        {
            "message": "hired_on must be a valid Date"
        },
        {
            "message": "per_page cannot be more than maximum",
            "max": 50
        },
        {
            "message": "states is an invalid value",
            "valid_values": ["active", "inactive"]
        },

    ]
}

HTML

By default responses are returned in JSON format. To return responses as an empty HTML response with a 400 Bad Request status, change the :format option in the validate_params methods to :html.

Example:

validate_params :index, format: :html do |p|
    p.param :name, String, default: "John Doe"
end

Development

After checking out the repo, run bin/setup to install dependencies. Then, run rspec 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 the created tag, and push the .gem file to rubygems.org.

Contributing

Bug reports and pull requests are welcome on GitHub at https://github.com/peopleforce/validate_params.

Credits

Built by the team at PeopleForce, the HRM for small to medium sized tech businesses.