module Validations

Overview

Enables the including type to define attribute validations.

struct User
  include Validations

  property name : String
  property email : String
  @age : UInt8?
  @nilable : String?

  def initialize(@name, @email, @age : UInt8? = nil, @nilable : String? = nil)
  end

  validate name, size: (1..16)
  validate email, size: (6..64), regex: /\w+@\w+\.\w{2,}/
  validate @age, gte: 18

  # Will not be run if `@nilable.nil?`
  validate @nilable, size: (5..10)

  # Custom validations are allowed
  def validate
    previous_def
    invalidate("name", "must not be equal to Vadim") if name == "Vadim"
  end
end

user = User.new("Vadim", "e-mail", 17)
pp user.valid?
# false
pp user.invalid_attributes
# {
#   "name" => ["must have size in (1..16)", "must not be equal to Vadim"],
#   "email" => ["must have size in (6..64)", "must match /\\w+@\\w+\\.\\w{2,}/"],
#   "@age" => ["must be greater than or equal to 18"]
# }

Defined in:

Instance Method Summary

• #invalid_attributes

  A hash of invalid attributes, if any.

• #valid!

  Roughly check if the including type is valid, raising Error otherwise.

• #valid?

  Gently check if the including type is valid.

Macro Summary

• invalidate(attribute, message)

  Mark attribute as invalid with message.

• validate(attribute, **rules)

  Validate attribute with inline rules unless it's nil.

Instance Method Detail

pp user.invalid_attributes
# {"name" => ["is too long"], ["is not Slav enough"]}

Macro Detail

validate name, size: (1..16)
validate email, regex: /\w+@\w+\.\w{2,}/
validate age, gte: 18

def validate
  previous_def # Mandatory, otherwise previous validations won't run
  invalidate("name", "some error") if name == "Foo"
end