ObjectValidator

ObjectValidator is a set of simple module mixins for validating Plain Old Ruby Object data. A lightweight alternative to ActiveModel. As of now it has small set of validations - but these are easily extensible.

Add this line to your application's Gemfile:

gem 'object_validator'

And then execute:

$ bundle

Or install it yourself as:

$ gem install object_validator

To include validation on an object, we must do:

include ObjectValidator::Validate

So, given a Person object, we would have:

class Person
  include ObjectValidator::Validate

  attr_accessor :name, :email, :details, :age, :uri
end

We must then create an accompanying Validator object. The Validator object must be named appropriately. This is simply the name of the object in question, with the addition of 'Validator'. With our Person object, it would look like this.

class PersonValidator
  include ObjectValidator::Validator

  validates :name, presence: true, type: String
  validates :details, keys: [:number, :street, :phone]
  validates :age, greater_than: 0
  validates :uri, with: { proc: proc { |p| p.uri.length > 5 }, msg: 'is too short' }
end

With this, we can now do the following with our Person object.

person = Person.new
person.valid? => false
person.errors => #<ObjectValidator::Errors:0x0055b508b1b9b8 @all={:name=>["must not be Nil", "must be a String"], :details=>["does not contain required Hash keys"], :age=>["value is less than required"], :uri=>["is too short"]}>
person.errors.full_messages = > ["Name must not be Nil.", "Name must be a String.", "Details does not contain required Hash keys.", "Age value is less than required.", "Uri is too short."]

As of now, the following validations are available:

Checks whether the attribute is nil or empty.

validates :example, presence: true

Checks whether the attribute is of a certain type.

validates :example, type: String

Checks whether the attribute is a Hash and contains certain keys.

validates :example, keys: [:number, :street, :phone]

Checks whether the attribute is Numeric and greater than a value.

validates :example, greater_than: 0

A general purpose validator. The proc will be run, and a returned value of true will result in a pass. The proc will be passed the object being validated. You must also assign a custom message.

validates :example, with: { proc: proc { |e| e.example.length > 5 }, msg: 'is too short' }

You can easily add more validations. Simply create a new class within ObjectValidator::Checks. The name of the class represents the key that can be used for validation. Within the check, you will have access to the following:

• name - The symbol of the attribute being validated.
• method - The attribute being validated.
• value - The value that is passed to the check.
• errors - The error object for the object we are validating.

For example, this is the Type check.

module ObjectValidator
  module Checks
    class Type < Base
      def call
        return if method.is_a?(value)
        errors.add(name, "must be a #{value.name}")
      end
    end
  end
end

Simply return if the check passes. Otherwise, we can add a new error.

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.

Bug reports and pull requests are welcome on GitHub at https://github.com/[USERNAME]/object_validator. 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.