class Supercast::DataObject

Public Class Methods

construct_from(values, opts = {}) click to toggle source
# File lib/supercast/data_object.rb, line 24
def self.construct_from(values, opts = {})
  values = Supercast::Util.symbolize_names(values)

  # work around protected #initialize_from for now
  new(values[:id]).send(:initialize_from, values, opts)
end
new(id = nil, opts = {}) click to toggle source
# File lib/supercast/data_object.rb, line 12
def initialize(id = nil, opts = {})
  id, @retrieve_params = Util.normalize_id(id)
  @opts = Util.normalize_opts(opts)
  @original_values = {}
  @values = {}
  # This really belongs in Resource, but not putting it there allows us
  # to have a unified inspect method
  @unsaved_values = Set.new
  @transient_values = Set.new
  @values[:id] = id if id
end
protected_fields() click to toggle source

A protected field is one that doesn't get an accessor assigned to it (i.e. `obj.public = …`) and one which is not allowed to be updated via the class level `Model.update(id, { … })`.

# File lib/supercast/data_object.rb, line 191
def self.protected_fields
  []
end

Private Class Methods

deep_copy(obj) click to toggle source

Produces a deep copy of the given object including support for arrays, hashes, and DataObjects.

# File lib/supercast/data_object.rb, line 378
                     def self.deep_copy(obj)
  case obj
  when Array
    obj.map { |e| deep_copy(e) }
  when Hash
    obj.each_with_object({}) do |(k, v), copy|
      copy[k] = deep_copy(v)
      copy
    end
  when DataObject
    obj.class.construct_from(
      deep_copy(obj.instance_variable_get(:@values)),
      obj.instance_variable_get(:@opts).select do |k, _v|
        Util::OPTS_COPYABLE.include?(k)
      end
    )
  else
    obj
  end
end

Public Instance Methods

==(other) click to toggle source

Determines the equality of two Supercast objects. Supercast objects are considered to be equal if they have the same set of values and each one of those values is the same.

# File lib/supercast/data_object.rb, line 34
def ==(other)
  other.is_a?(DataObject) &&
    @values == other.instance_variable_get(:@values)
end
[](key) click to toggle source
# File lib/supercast/data_object.rb, line 88
def [](key)
  @values[key.to_sym]
end
[]=(key, value) click to toggle source
# File lib/supercast/data_object.rb, line 92
def []=(key, value)
  send(:"#{key}=", value)
end
as_json(*opts) click to toggle source
# File lib/supercast/data_object.rb, line 108
def as_json(*opts)
  @values.as_json(*opts)
end
dirty!() click to toggle source

Sets all keys within the DataObject as unsaved so that they will be included with an update when serialize_params is called.

# File lib/supercast/data_object.rb, line 133
def dirty!
  @unsaved_values = Set.new(@values.keys)

  @values.each_value do |v|
    dirty_value!(v)
  end
end
each(&blk) click to toggle source
# File lib/supercast/data_object.rb, line 127
def each(&blk)
  @values.each(&blk)
end
eql?(other) click to toggle source

Hash equality. As with `#==`, we consider two equivalent Supercast objects equal.

# File lib/supercast/data_object.rb, line 41
def eql?(other)
  # Defer to the implementation on `#==`.
  self == other
end
hash() click to toggle source

As with equality in `#==` and `#eql?`, we hash two Supercast objects to the same value if they're equivalent objects.

# File lib/supercast/data_object.rb, line 48
def hash
  @values.hash
end
inspect() click to toggle source
# File lib/supercast/data_object.rb, line 56
def inspect
  id_string = respond_to?(:id) && !id.nil? ? " id=#{id}" : ''
  "#<#{self.class}:0x#{object_id.to_s(16)}#{id_string}> JSON: " +
    JSON.pretty_generate(@values)
end
keys() click to toggle source
# File lib/supercast/data_object.rb, line 96
def keys
  @values.keys
end
marshal_dump() click to toggle source

Implements custom encoding for Ruby's Marshal. The data produced by this method should be comprehendable by marshal_load.

This allows us to remove certain features that cannot or should not be serialized.

# File lib/supercast/data_object.rb, line 146
def marshal_dump
  # The Client instance in @opts is not serializable and is not
  # really a property of the DataObject, so we exclude it when
  # dumping
  opts = @opts.clone
  opts.delete(:client)
  [@values, opts]
end
marshal_load(data) click to toggle source

Implements custom decoding for Ruby's Marshal. Consumes data that's produced by marshal_dump.

# File lib/supercast/data_object.rb, line 157
def marshal_load(data)
  values, opts = data
  initialize(values[:id])
  initialize_from(values, opts)
end
serialize_params(options = {}) click to toggle source
# File lib/supercast/data_object.rb, line 163
def serialize_params(options = {})
  update_hash = {}

  @values.each do |k, _v|
    # There are a few reasons that we may want to add in a parameter for
    # update:
    #
    #   1. The `force` option has been set.
    #   2. We know that it was modified.
    #
    unsaved = @unsaved_values.include?(k)
    next unless options[:force] || unsaved

    update_hash[k.to_sym] = serialize_params_value(
      @values[k], @original_values[k], unsaved, options[:force], key: k
    )
  end

  # a `nil` that makes it out of `#serialize_params_value` signals an empty
  # value that we shouldn't appear in the serialized form of the object
  update_hash.reject! { |_, v| v.nil? }

  update_hash
end
to_hash() click to toggle source
# File lib/supercast/data_object.rb, line 112
def to_hash
  maybe_to_hash = lambda do |value|
    value&.respond_to?(:to_hash) ? value.to_hash : value
  end

  @values.each_with_object({}) do |(key, value), acc|
    acc[key] = case value
               when Array
                 value.map(&maybe_to_hash)
               else
                 maybe_to_hash.call(value)
               end
  end
end
to_json(_opts) click to toggle source
# File lib/supercast/data_object.rb, line 104
def to_json(_opts)
  JSON.generate(@values)
end
to_s(*_args) click to toggle source
# File lib/supercast/data_object.rb, line 52
def to_s(*_args)
  JSON.pretty_generate(to_hash)
end
update_attributes(values, opts = {}, dirty: true) click to toggle source

Mass assigns attributes on the model.

This is a version of update_attributes that takes some extra options for internal use.

Attributes

  • values - Hash of values to use to update the current attributes of the object.

  • opts - Options for DataObject like an API key that will be reused on subsequent API calls.

Options

  • :dirty - Whether values should be initiated as “dirty” (unsaved) and which applies only to new DataObjects being initiated under this DataObject. Defaults to true.

# File lib/supercast/data_object.rb, line 79
def update_attributes(values, opts = {}, dirty: true)
  values.each do |k, v|
    add_accessors([k], values) unless metaclass.method_defined?(k.to_sym)
    @values[k] = Util.convert_to_supercast_object(v, opts)
    dirty_value!(@values[k]) if dirty
    @unsaved_values.add(k)
  end
end
values() click to toggle source
# File lib/supercast/data_object.rb, line 100
def values
  @values.values
end

Protected Instance Methods

add_accessors(keys, values) click to toggle source
Calls superclass method
# File lib/supercast/data_object.rb, line 226
def add_accessors(keys, values)
  # not available in the #instance_eval below
  protected_fields = self.class.protected_fields

  metaclass.instance_eval do
    keys.each do |k|
      next if protected_fields.include?(k)
      next if @@permanent_attributes.include?(k)

      if k == :method
        # Object#method is a built-in Ruby method that accepts a symbol
        # and returns the corresponding Method object. Because the API may
        # also use `method` as a field name, we check the arity of *args
        # to decide whether to act as a getter or call the parent method.
        define_method(k) { |*args| args.empty? ? @values[k] : super(*args) }
      else
        define_method(k) { @values[k] }
      end

      define_method(:"#{k}=") do |v|
        if v == ''
          raise ArgumentError, "You cannot set #{k} to an empty string. " \
            'We interpret empty strings as nil in requests. ' \
            "You may set (object).#{k} = nil to delete the property."
        end
        @values[k] = Util.convert_to_supercast_object(v, @opts)
        dirty_value!(@values[k])
        @unsaved_values.add(k)
      end

      define_method(:"#{k}?") { @values[k] } if [FalseClass, TrueClass].include?(values[k].class)
    end
  end
end
initialize_from(values, opts) click to toggle source

Re-initializes the object based on a hash of values (usually one that's come back from an API call). Adds or removes value accessors as necessary and updates the state of internal data.

Protected on purpose! Please do not expose.

Options

  • :values: Hash used to update accessors and values.

  • :opts: Options for DataObject like an API key.

# File lib/supercast/data_object.rb, line 320
def initialize_from(values, opts)
  @opts = Util.normalize_opts(opts)

  # the `#send` is here so that we can keep this method private
  @original_values = self.class.send(:deep_copy, values)

  removed = Set.new(@values.keys - values.keys)
  added = Set.new(values.keys - @values.keys)

  remove_accessors(removed)
  add_accessors(added, values)

  removed.each do |k|
    @values.delete(k)
    @transient_values.add(k)
    @unsaved_values.delete(k)
  end

  update_attributes(values, opts, dirty: false)

  values.each_key do |k|
    @transient_values.delete(k)
    @unsaved_values.delete(k)
  end

  self
end
metaclass() click to toggle source
# File lib/supercast/data_object.rb, line 197
def metaclass
  class << self; self; end
end
method_missing(name, *args) click to toggle source

Disabling the cop because it's confused by the fact that the methods are protected, but we do define `#respond_to_missing?` just below. Hopefully this is fixed in more recent Rubocop versions.

Calls superclass method
# File lib/supercast/data_object.rb, line 264
def method_missing(name, *args)
  # TODO: only allow setting in updateable classes.
  if name.to_s.end_with?('=')
    attr = name.to_s[0...-1].to_sym

    # Pull out the assigned value. This is only used in the case of a
    # boolean value to add a question mark accessor (i.e. `foo?`) for
    # convenience.
    val = args.first

    # the second argument is only required when adding boolean accessors
    add_accessors([attr], attr => val)

    begin
      mth = method(name)
    rescue NameError
      raise NoMethodError,
            "Cannot set #{attr} on this object. HINT: you can't set: " \
            "#{@@permanent_attributes.to_a.join(', ')}"
    end
    return mth.call(args[0])
  elsif @values.key?(name)
    return @values[name]
  end

  begin
    super
  rescue NoMethodError => e
    # If we notice the accessed name if our set of transient values we can
    # give the user a slightly more helpful error message. If not, just
    # raise right away.
    raise unless @transient_values.include?(name)

    raise NoMethodError,
          e.message + ".  HINT: The '#{name}' attribute was set in the " \
          'past, however.  It was then wiped when refreshing the object ' \
          "with the result returned by Supercast's API, probably as a " \
          'result of a save().  The attributes currently available on ' \
          "this object are: #{@values.keys.join(', ')}"
  end
end
remove_accessors(keys) click to toggle source
# File lib/supercast/data_object.rb, line 201
def remove_accessors(keys)
  # not available in the #instance_eval below
  protected_fields = self.class.protected_fields

  metaclass.instance_eval do
    keys.each do |k|
      next if protected_fields.include?(k)
      next if @@permanent_attributes.include?(k)

      # Remove methods for the accessor's reader and writer.
      [k, :"#{k}=", :"#{k}?"].each do |method_name|
        next unless method_defined?(method_name)

        begin
          remove_method(method_name)
        rescue NameError
          warn("WARNING: Unable to remove method `#{method_name}`; " \
            "if custom, please consider renaming to a name that doesn't " \
            'collide with an API property name.')
        end
      end
    end
  end
end
respond_to_missing?(symbol, include_private = false) click to toggle source
Calls superclass method
# File lib/supercast/data_object.rb, line 306
def respond_to_missing?(symbol, include_private = false)
  @values&.key?(symbol) || super
end
serialize_params_value(value, original, _unsaved, force) click to toggle source
# File lib/supercast/data_object.rb, line 348
def serialize_params_value(value, original, _unsaved, force)
  if value.nil?
    ''
  elsif value.is_a?(Array)
    update = value.map { |v| serialize_params_value(v, nil, true, force) }

    # This prevents an array that's unchanged from being resent.
    update if update != serialize_params_value(original, nil, true, force)

  # Handle a Hash for now, but in the long run we should be able to
  # eliminate all places where hashes are stored as values internally by
  # making sure any time one is set, we convert it to a DataObject. This
  # will simplify our model by making data within an object more
  # consistent.
  #
  # For now, you can still run into a hash if someone appends one to an
  # existing array being held by a DataObject. This could happen for
  # example by appending a new hash onto `additional_owners` for an
  # account.
  elsif value.is_a?(Hash)
    Util.convert_to_supercast_object(value, @opts).serialize_params
  elsif value.is_a?(DataObject)
    value.serialize_params(force: force)
  else
    value
  end
end

Private Instance Methods

dirty_value!(value) click to toggle source
# File lib/supercast/data_object.rb, line 401
def dirty_value!(value)
  case value
  when Array
    value.map { |v| dirty_value!(v) }
  when DataObject
    value.dirty!
  end
end