Module: JsonbAccessor::Macro::ClassMethods

Defined in:
lib/jsonb_accessor/macro.rb

Instance Method Summary collapse

Instance Method Details

#jsonb_accessor(jsonb_attribute, field_types) ⇒ Object 



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# File 'lib/jsonb_accessor/macro.rb', line 6

def jsonb_accessor(jsonb_attribute, field_types)
  names_and_store_keys = field_types.each_with_object({}) do |(name, type), mapping|
    _type, options = Array(type)
    mapping[name.to_s] = (options.try(:delete, :store_key) || name).to_s
  end

  # Defines virtual attributes for each jsonb field.
  field_types.each do |name, type|
    next attribute name, type unless type.is_a?(Array)
    next attribute name, *type unless type.last.is_a?(Hash)

    *args, keyword_args = type
    attribute name, *args, **keyword_args
  end

  store_key_mapping_method_name = "jsonb_store_key_mapping_for_#{jsonb_attribute}"
  # Defines methods on the model class
  class_methods = Module.new do
    # Allows us to get a mapping of field names to store keys scoped to the column
    define_method(store_key_mapping_method_name) do
      superclass_mapping = superclass.try(store_key_mapping_method_name) || {}
      superclass_mapping.merge(names_and_store_keys)
    end
  end
  # We extend with class methods here so we can use the results of methods it defines to define more useful methods later
  extend class_methods

  # Get field names to default values mapping
  names_and_defaults = field_types.each_with_object({}) do |(name, type), mapping|
    _type, options = Array(type)
    field_default = options.try(:delete, :default)
    mapping[name.to_s] = field_default unless field_default.nil?
  end

  # Get store keys to default values mapping
  store_keys_and_defaults = JsonbAccessor::Helpers.convert_keys_to_store_keys(names_and_defaults, public_send(store_key_mapping_method_name))

  # Define jsonb_defaults_mapping_for_<jsonb_attribute>
  defaults_mapping_method_name = "jsonb_defaults_mapping_for_#{jsonb_attribute}"
  class_methods.instance_eval do
    define_method(defaults_mapping_method_name) do
      superclass_mapping = superclass.try(defaults_mapping_method_name) || {}
      superclass_mapping.merge(store_keys_and_defaults)
    end
  end

  all_defaults_mapping = public_send(defaults_mapping_method_name)
  # Fields may have procs as default value. This means `all_defaults_mapping` may contain procs as values. To make this work
  # with the attributes API, we need to wrap `all_defaults_mapping` with a proc itself, making sure it returns a plain hash
  # each time it is evaluated.
  all_defaults_mapping_proc =
    if all_defaults_mapping.present?
      -> { all_defaults_mapping.transform_values { |value| value.respond_to?(:call) ? value.call : value }.to_h.compact }
    end
  attribute jsonb_attribute, :jsonb, default: all_defaults_mapping_proc if all_defaults_mapping_proc.present?

  # Setters are in a module to allow users to override them and still be able to use `super`.
  setters = Module.new do
    # Overrides the setter created by `attribute` above to make sure the jsonb attribute is kept in sync.
    names_and_store_keys.each do |name, store_key|
      define_method("#{name}=") do |value|
        super(value)

        attribute_value = public_send(name)
        # Rails always saves time based on `default_timezone`. Since #as_json considers timezone, manual conversion is needed
        if attribute_value.acts_like?(:time)
          attribute_value = (JsonbAccessor::Helpers.active_record_default_timezone == :utc ? attribute_value.utc : attribute_value.in_time_zone).strftime("%F %R:%S.%L")
        end

        new_values = (public_send(jsonb_attribute) || {}).merge(store_key => attribute_value)
        write_attribute(jsonb_attribute, new_values)
      end
    end

    # Overrides the jsonb attribute setter to make sure the jsonb fields are kept in sync.
    define_method("#{jsonb_attribute}=") do |value|
      value ||= {}
      names_to_store_keys = self.class.public_send(store_key_mapping_method_name)

      # this is the raw hash we want to save in the jsonb_attribute
      value_with_store_keys = JsonbAccessor::Helpers.convert_keys_to_store_keys(value, names_to_store_keys)
      write_attribute(jsonb_attribute, value_with_store_keys)

      # this maps attributes to values
      value_with_named_keys = JsonbAccessor::Helpers.convert_store_keys_to_keys(value, names_to_store_keys)

      empty_named_attributes = names_to_store_keys.transform_values { nil }
      empty_named_attributes.merge(value_with_named_keys).each do |name, attribute_value|
        # Only proceed if this attribute has been defined using `jsonb_accessor`.
        next unless names_to_store_keys.key?(name)

        write_attribute(name, attribute_value)
      end
    end
  end
  include setters

  # Makes sure new objects have the appropriate values in their jsonb fields.
  after_initialize do
    next unless has_attribute? jsonb_attribute

    jsonb_values = public_send(jsonb_attribute) || {}
    jsonb_values.each do |store_key, value|
      name = names_and_store_keys.key(store_key)
      next unless name

      write_attribute(
        name,
        JsonbAccessor::Helpers.deserialize_value(value, self.class.type_for_attribute(name).type)
      )
      clear_attribute_change(name) if persisted?
    end
  end

  JsonbAccessor::AttributeQueryMethods.new(self).define(store_key_mapping_method_name, jsonb_attribute)
end