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 ]
INTERNAL_OPTIONS =

Options we don't want to expose when describing attributes

[:dsl_compiler,:dsl_compiler_options]

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 26

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

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

  check_options!
end

Instance Attribute Details

#optionsObject (readonly)

Returns the value of attribute options


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# File 'lib/attributor/attribute.rb', line 22

def options
  @options
end

#typeObject (readonly)

Returns the value of attribute type


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# File 'lib/attributor/attribute.rb', line 22

def type
  @type
end

Instance Method Details

#==(attribute) ⇒ Object

Raises:

  • (ArgumentError)

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# File 'lib/attributor/attribute.rb', line 37

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

  self.type == attribute.type &&
    self.options == attribute.options
end

#attributesObject


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# File 'lib/attributor/attribute.rb', line 184

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

#check_option!(name, definition) ⇒ Object

TODO: override in type subclass


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# File 'lib/attributor/attribute.rb', line 283

def check_option!(name, definition)
  case name
  when :values
    raise AttributorException.new("Allowed set of values requires an array. Got (#{definition})") unless definition.is_a? ::Array
  when :default
    raise AttributorException.new("Default value doesn't have the correct attribute type. Got (#{definition.inspect})") unless self.type.valid_type?(definition) || definition.kind_of?(Proc)
    self.options[:default] = self.load(definition) unless definition.kind_of?(Proc)
  when :description
    raise AttributorException.new("Description value must be a string. Got (#{definition})") unless definition.is_a? ::String
  when :required
    raise AttributorException.new("Required must be a boolean") unless !!definition == definition # Boolean check
    raise AttributorException.new("Required cannot be enabled in combination with :default") if definition == true && options.has_key?(:default)
  when :required_if
    raise AttributorException.new("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.new("Required_if cannot be specified together with :required") if self.options[:required]
  when :example
    unless definition.is_a?(::Regexp) || definition.is_a?(::String) || definition.is_a?(::Array) || definition.is_a?(::Proc) || definition.nil? || self.type.valid_type?(definition)
      raise AttributorException.new("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.new("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 269

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

  true
end

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


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# File 'lib/attributor/attribute.rb', line 102

def describe(shallow=true, example: nil)
  description = { }
  # Clone the common options
  TOP_LEVEL_OPTIONS.each do |option_name|
    description[option_name] = self.options[option_name] if self.options.has_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 = self.options.keys - TOP_LEVEL_OPTIONS - INTERNAL_OPTIONS
  description[:options] = {} unless special_options.empty?
  special_options.each do |opt_name|
    description[:options][opt_name] = self.options[opt_name]
  end
  # Change the reference option to the actual class name.
  if ( reference = self.options[:reference] )
    description[:options][:reference] = reference.name
  end

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

  description
end

#dump(value, **opts) ⇒ Object


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# File 'lib/attributor/attribute.rb', line 82

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 155

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 self.options.has_key? :example
    loaded = example_from_options(parent, context)
    errors = self.validate(loaded, context)
    raise AttributorException, "Error generating example for #{Attributor.humanize_context(context)}. Errors: #{errors.inspect}" if errors.any?
    loaded
  else
    if (option_values = self.options[:values])
      option_values.pick
    else
      if type.respond_to?(:attributes)
        self.type.example(context, values)
      else
        self.type.example(context, options: self.options)
      end
    end
  end
end

#example_from_options(parent, context) ⇒ Object


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# File 'lib/attributor/attribute.rb', line 134

def example_from_options(parent, context)
  val = self.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
  self.load( generated, context )
end

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


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# File 'lib/attributor/attribute.rb', line 53

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

  if value.nil? && self.options.has_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 45

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

  errors = self.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 194

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 self.validate_missing_value(context)
  end

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

  errors = self.validate_type(object,context)

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

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

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

#validate_missing_value(context) ⇒ Object


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# File 'lib/attributor/attribute.rb', line 219

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 self.options[:required]

  # Missing attribute was not required if :required_if (and :required)
  # option was NOT set
  requirement = self.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.new("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

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

    [message]
  else
    []
  end
end

#validate_type(value, context) ⇒ Object


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# File 'lib/attributor/attribute.rb', line 87

def validate_type(value, context)
  # delegate check to type subclass if it exists
  unless self.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: #{self.type.name})"
    return [msg]
  end
  []
end