simple ruby json schema validator

json_schem_validator.rb

require "set"
module JsonSchemValidator
  TYPES = {
    "Hash" => Hash,
    "hash" => Hash,
    "object" => Hash,

    "Array" => Array,
    "array" => Array,
    "list" => Array,

    "Integer" => Integer,
    "integer" => Integer,
    "int" => Integer,

    "Float" => Float,
    "float" => Float,

    "String" => String,
    "string" => String,

    "Boolean" => [TrueClass, FalseClass],
    "boolean" => [TrueClass, FalseClass],
    "Bool" => [TrueClass, FalseClass],
    "bool" => [TrueClass, FalseClass],
  }
  def self.validate(json, yaml) 
    def self.check(key, value, schema)
      raise Exception.new("Schema is InValid: need Type") unless schema.key? 'type'
      raise Exception.new("Schema is InValid: #{schema['type']} is unknown") unless TYPES.key? schema['type']
      type = TYPES[schema['type']]

      if type == Hash
        raise Exception.new("Json is InValid: #{key} must be Hash") unless valid_type? value, type
        raise Exception.new("Json is InValid: #{key} must be required sufficient properties, nearby #{schema['required'].join(',')}") unless schema['required'].to_set.subset?(value.keys.to_set)
        value.each do |child_key, child_value|
          check_each(child_key, child_value, schema['properties'][child_key])
        end
      elsif type == Array
          raise Exception.new("Json is InValid: #{key} must be Array") unless valid_type? value, type
          raise Exception.new("Schema is InValid: #{key} need items") unless schema.key? 'items'
          value.each do |item|
            check_each("ArrayItems::#{key}", item, schema['items'])
          end
      else
        raise Exception.new("Json is InValid: #{key} must be #{schema['type']}") unless valid_type? value, type
      end
    end

    def self.valid_type?(value, type)
      if type.is_a? Array
        type.inject(false){|bool, _type| (bool or value.is_a? _type)}
      else
        value.is_a? type
      end
    end

    check("schema", json, yaml)
  end
end