Class: Dynamoid::TransactionWrite::UpdateUpsert

Inherits:
Action
  • Object
show all
Defined in:
lib/dynamoid/transaction_write/update_upsert.rb

Direct Known Subclasses

Update, Upsert

Constant Summary

Constants inherited from Action

Action::VALID_OPTIONS

Instance Attribute Summary

Attributes inherited from Action

#additions, #attributes, #deletions, #model, #options, #removals

Instance Method Summary collapse

Methods inherited from Action

#add, #add_timestamps, #changes_applied, #delete, #find_from_attributes, #hash_key, #model_class, #raise_validation_error?, #range_key, #run_callbacks, #sanitize_item, #set, #skip_callbacks?, #skip_validation?, #touch_model_timestamps, #valid?, #write_attributes_to_model

Constructor Details

#initialize(model_or_model_class, attributes = {}, options = {}, &block) ⇒ UpdateUpsert

Returns a new instance of UpdateUpsert.



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# File 'lib/dynamoid/transaction_write/update_upsert.rb', line 8

def initialize(model_or_model_class, attributes = {}, options = {}, &block)
  super(model_or_model_class, attributes, options, &block)

  write_attributes_to_model
end

Instance Method Details

#to_h ⇒ Object

shared by Update and Upsert



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# File 'lib/dynamoid/transaction_write/update_upsert.rb', line 15

def to_h
  if model
    # model.hash_key = SecureRandom.uuid if model.hash_key.blank?
    touch_model_timestamps(skip_created_at: true)
    changes = model.changes.map { |k, v| [k.to_sym, v[1]] }.to_h # hash of dirty attributes
  else
    changes = attributes.clone || {}
    # changes[model_class.hash_key] = SecureRandom.uuid
    changes = add_timestamps(changes, skip_created_at: true)
  end
  changes.delete(model_class.hash_key) # can't update id!
  changes.delete(model_class.range_key) if model_class.range_key?
  item = Dynamoid::Dumping.dump_attributes(changes, model_class.attributes)

  # set 'key' that is used to look up record for updating
  key = { model_class.hash_key => hash_key }
  key[model_class.range_key] = range_key if model_class.range_key?

  # e.g. "SET #updated_at = :updated_at ADD record_count :i"
  item_keys = item.keys
  update_expression = "SET #{item_keys.each_with_index.map { |_k, i| "#_n#{i} = :_s#{i}" }.join(', ')}"

  # e.g. {":updated_at" => 1645453.234, ":i" => 1}
  expression_attribute_values = item_keys.each_with_index.map { |k, i| [":_s#{i}", item[k]] }.to_h
  expression_attribute_names = {}

  update_expression = set_additions(expression_attribute_values, update_expression)
  update_expression = set_deletions(expression_attribute_values, update_expression)
  expression_attribute_names, update_expression = set_removals(expression_attribute_names, update_expression)

  # only alias names for fields in models, other values such as for ADD do not have them
  # e.g. {"#updated_at" => "updated_at"}
  # attribute_keys_in_model = item_keys.intersection(model_class.attributes.keys)
  # expression_attribute_names = attribute_keys_in_model.map{|k| ["##{k}","#{k}"]}.to_h
  expression_attribute_names.merge!(item_keys.each_with_index.map { |k, i| ["#_n#{i}", k.to_s] }.to_h)

  condition_expression = "attribute_exists(#{model_class.hash_key})" # fail if record is missing
  condition_expression += " and attribute_exists(#{model_class.range_key})" if model_class.range_key? # needed?

  result = {
    update: {
      key: key,
      table_name: model_class.table_name,
      update_expression: update_expression,
      expression_attribute_values: expression_attribute_values
    }
  }
  result[:update][:expression_attribute_names] = expression_attribute_names if expression_attribute_names.present?
  result[:update][:condition_expression] = condition_expression unless options[:skip_existence_check]

  result
end