Dry validation: missing logic example

dry-validation-logic.rb

require 'dry-validation'

Parameter = Dry::Schema.JSON do
  required(:name).filled(:string)
end

Reference = Dry::Schema.JSON do
  required(:$ref).filled(:string)
end

Operation = Dry::Schema.JSON do
  required(:parameters).each(:hash, Parameter)
  # What would be perfect here imo: required(:parameters).each(:hash, Parameter | Reference)
  # Note: I cannot make `$ref` and `name` optional in a single schema, as we need to verify that it matches one of the other form
end

class Contract < Dry::Validation::Contract
  json do
    required(:paths).each(:hash) do
      required(:get).hash(Operation)
    end
  end
end

valid_hash = {
  'paths' => [
    {
      'get' => {
        'parameters' => [
          { 'name' => 'hello' },
          { '$ref' => '#/internal/ref' }
        ]
      }
    }
  ]
}

result = Contract.new.call(valid_hash)

if result.success?
  puts "Valid"
else
  puts "Invalid:"
  result.errors.each { |e| puts "- #{e.path.join('.') + ' ' + e.text}" }
end