Class: Attributor::Attribute

Inherits:
Object
  • Object
show all
Defined in:
lib/attributor/attribute.rb

Overview

It is the abstract base class to hold an attribute, both a leaf and a container (hash/Array…) TODO: should this be a mixin since it is an abstract class?

Constant Summary collapse

TOP_LEVEL_OPTIONS = 
[:description, :values, :default, :example, :required, :required_if, :custom_data].freeze
INTERNAL_OPTIONS =

Options we don’t want to expose when describing attributes

[:dsl_compiler, :dsl_compiler_options].freeze

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(type, options = {}, &block) ⇒ Attribute

@options: metadata about the attribute @block: code definition for struct attributes (nil for predefined types or leaf/simple types)



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# File 'lib/attributor/attribute.rb', line 27

def initialize(type, options = {}, &block)
  @type = Attributor.resolve_type(type, options, block)

  @options = options
  @options = @type.options.merge(@options) if @type.respond_to?(:options)

  check_options!
end

Instance Attribute Details

#options ⇒ Object (readonly)

Returns the value of attribute options.



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# File 'lib/attributor/attribute.rb', line 23

def options
  @options
end

#type ⇒ Object (readonly)

Returns the value of attribute type.



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# File 'lib/attributor/attribute.rb', line 23

def type
  @type
end

Instance Method Details

#==(other) ⇒ Object

Raises:

  • (ArgumentError) 


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# File 'lib/attributor/attribute.rb', line 36

def ==(other)
  raise ArgumentError, "can not compare Attribute with #{other.class.name}" unless other.is_a?(Attribute)

  type == other.type &&
    options == other.options
end

#attributes ⇒ Object 



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# File 'lib/attributor/attribute.rb', line 175

def attributes
  type.attributes if @type_has_attributes ||= type.respond_to?(:attributes)
end

#check_option!(name, definition) ⇒ Object

TODO: override in type subclass



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# File 'lib/attributor/attribute.rb', line 265

def check_option!(name, definition)
  case name
  when :values
    raise AttributorException, "Allowed set of values requires an array. Got (#{definition})" unless definition.is_a? ::Array
  when :default
    raise AttributorException, "Default value doesn't have the correct attribute type. Got (#{definition.inspect})" unless type.valid_type?(definition) || definition.is_a?(Proc)
    options[:default] = load(definition) unless definition.is_a?(Proc)
  when :description
    raise AttributorException, "Description value must be a string. Got (#{definition})" unless definition.is_a? ::String
  when :required
    raise AttributorException, 'Required must be a boolean' unless definition == true || definition == false
    raise AttributorException, 'Required cannot be enabled in combination with :default' if definition == true && options.key?(:default)
  when :required_if
    raise AttributorException, 'Required_if must be a String, a Hash definition or a Proc' unless definition.is_a?(::String) || definition.is_a?(::Hash) || definition.is_a?(::Proc)
    raise AttributorException, 'Required_if cannot be specified together with :required' if options[:required]
  when :example
    unless definition.is_a?(::Regexp) || definition.is_a?(::String) || definition.is_a?(::Array) || definition.is_a?(::Proc) || definition.nil? || type.valid_type?(definition)
      raise AttributorException, "Invalid example type (got: #{definition.class.name}). It must always match the type of the attribute (except if passing Regex that is allowed for some types)"
    end
  when :custom_data
    raise AttributorException, "custom_data must be a Hash. Got (#{definition})" unless definition.is_a?(::Hash)
  else
    return :unknown # unknown option
  end

  :ok # passes
end

#check_options! ⇒ Object 



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# File 'lib/attributor/attribute.rb', line 253

def check_options!
  options.each do |option_name, option_value|
    next unless check_option!(option_name, option_value) == :unknown
    if type.check_option!(option_name, option_value) == :unknown
      raise AttributorException, "unsupported option: #{option_name} with value: #{option_value.inspect} for attribute: #{inspect}"
    end
  end

  true
end

#describe(shallow = true, example: nil) ⇒ Object 



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# File 'lib/attributor/attribute.rb', line 97

def describe(shallow = true, example: nil)
  description = {}
  # Clone the common options
  TOP_LEVEL_OPTIONS.each do |option_name|
    description[option_name] = options[option_name] if options.key? option_name
  end

  # Make sure this option definition is not mistaken for the real generated example
  if (ex_def = description.delete(:example))
    description[:example_definition] = ex_def
  end

  special_options = options.keys - TOP_LEVEL_OPTIONS - INTERNAL_OPTIONS
  description[:options] = {} unless special_options.empty?
  special_options.each do |opt_name|
    description[:options][opt_name] = options[opt_name]
  end
  # Change the reference option to the actual class name.
  if (reference = options[:reference])
    description[:options][:reference] = reference.name
  end

  description[:type] = type.describe(shallow, example: example)
  # Move over any example from the type, into the attribute itself
  if (ex = description[:type].delete(:example))
    description[:example] = dump(ex)
  end

  description
end

#dump(value, **opts) ⇒ Object 



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# File 'lib/attributor/attribute.rb', line 79

def dump(value, **opts)
  type.dump(value, **opts)
end

#example(context = nil, parent: nil, values: {}) ⇒ Object

Raises:

  • (ArgumentError) 


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# File 'lib/attributor/attribute.rb', line 149

def example(context = nil, parent: nil, values: {})
  raise ArgumentError, 'attribute example cannot take a context of type String' if context.is_a? ::String
  if context
    ctx = Attributor.humanize_context(context)
    seed, = Digest::SHA1.digest(ctx).unpack('QQ')
    Random.srand(seed)
  else
    context = Attributor::DEFAULT_ROOT_CONTEXT
  end

  if options.key? :example
    loaded = example_from_options(parent, context)
    errors = validate(loaded, context)
    raise AttributorException, "Error generating example for #{Attributor.humanize_context(context)}. Errors: #{errors.inspect}" if errors.any?
    return loaded
  end

  return options[:values].pick if options.key? :values

  if type.respond_to?(:attributes)
    type.example(context, values)
  else
    type.example(context, options: options)
  end
end

#example_from_options(parent, context) ⇒ Object 



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# File 'lib/attributor/attribute.rb', line 128

def example_from_options(parent, context)
  val = options[:example]
  generated = case val
              when ::Regexp
                val.gen
              when ::Proc
                if val.arity == 2
                  val.call(parent, context)
                elsif val.arity == 1
                  val.call(parent)
                else
                  val.call
                end
              when nil
                nil
              else
                val
              end
  load(generated, context)
end

#load(value, context = Attributor::DEFAULT_ROOT_CONTEXT, **options) ⇒ Object 



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# File 'lib/attributor/attribute.rb', line 50

def load(value, context = Attributor::DEFAULT_ROOT_CONTEXT, **options)
  value = type.load(value, context, **options)

  if value.nil? && self.options.key?(:default)
    defined_val = self.options[:default]
    val = case defined_val
          when ::Proc
            fake_parent = FakeParent.new
            # TODO: we can only support "context" as a parameter to the proc for now, since we don't have the parent...
            if defined_val.arity == 2
              defined_val.call(fake_parent, context)
            elsif defined_val.arity == 1
              defined_val.call(fake_parent)
            else
              defined_val.call
            end
          else
            defined_val
          end
    value = val # Need to load?
  end

  value
rescue AttributorException, NameError
  raise
rescue => e
  raise Attributor::LoadError, "Error loading attribute #{Attributor.humanize_context(context)} of type #{type.name} from value #{Attributor.errorize_value(value)}\n#{e.message}"
end

#parse(value, context = Attributor::DEFAULT_ROOT_CONTEXT) ⇒ Object 



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# File 'lib/attributor/attribute.rb', line 43

def parse(value, context = Attributor::DEFAULT_ROOT_CONTEXT)
  object = load(value, context)

  errors = validate(object, context)
  [object, errors]
end

#validate(object, context = Attributor::DEFAULT_ROOT_CONTEXT) ⇒ Object

Validates stuff and checks dependencies



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# File 'lib/attributor/attribute.rb', line 180

def validate(object, context = Attributor::DEFAULT_ROOT_CONTEXT)
  raise "INVALID CONTEXT!! #{context}" unless context
  # Validate any requirements, absolute or conditional, and return.

  if object.nil? # == Attributor::UNSET
    # With no value, we can only validate whether that is acceptable or not and return.
    # Beyond that, no further validation should be done.
    return validate_missing_value(context)
  end

  # TODO: support validation for other types of conditional dependencies based on values of other attributes

  errors = validate_type(object, context)

  # End validation if we don't even have the proper type to begin with
  return errors if errors.any?

  if options[:values] && !options[:values].include?(object)
    errors << "Attribute #{Attributor.humanize_context(context)}: #{Attributor.errorize_value(object)} is not within the allowed values=#{options[:values].inspect} "
  end

  errors + type.validate(object, context, self)
end

#validate_missing_value(context) ⇒ Object 



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# File 'lib/attributor/attribute.rb', line 204

def validate_missing_value(context)
  raise "INVALID CONTEXT!!! (got: #{context.inspect})" unless context.is_a? Enumerable

  # Missing attribute was required if :required option was set
  return ["Attribute #{Attributor.humanize_context(context)} is required"] if options[:required]

  # Missing attribute was not required if :required_if (and :required)
  # option was NOT set
  requirement = options[:required_if]
  return [] unless requirement

  case requirement
  when ::String
    key_path = requirement
    predicate = nil
  when ::Hash
    # TODO: support multiple dependencies?
    key_path = requirement.keys.first
    predicate = requirement.values.first
  else
    # should never get here if the option validation worked...
    raise AttributorException, "unknown type of dependency: #{requirement.inspect} for #{Attributor.humanize_context(context)}"
  end

  # chop off the last part
  requirement_context = context[0..-2]
  requirement_context_string = requirement_context.join(Attributor::SEPARATOR)

  # FIXME: we're having to reconstruct a string context just to use the resolver...smell.
  if AttributeResolver.current.check(requirement_context_string, key_path, predicate)
    message = "Attribute #{Attributor.humanize_context(context)} is required when #{key_path} "

    # give a hint about what the full path for a relative key_path would be
    unless key_path[0..0] == Attributor::AttributeResolver::ROOT_PREFIX
      message << "(for #{Attributor.humanize_context(requirement_context)}) "
    end

    message << if predicate
                 "matches #{predicate.inspect}."
               else
                 'is present.'
               end

    [message]
  else
    []
  end
end

#validate_type(value, context) ⇒ Object 



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# File 'lib/attributor/attribute.rb', line 83

def validate_type(value, context)
  # delegate check to type subclass if it exists
  unless type.valid_type?(value)
    msg = "Attribute #{Attributor.humanize_context(context)} received value: "
    msg += "#{Attributor.errorize_value(value)} is of the wrong type "
    msg += "(got: #{value.class.name}, expected: #{type.name})"
    return [msg]
  end
  []
end