Method: Dynamoid::TransactionWrite::Upsert#action_request

Defined in:
lib/dynamoid/transaction_write/upsert.rb

#action_request ⇒ Object 



40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
 
# File 'lib/dynamoid/transaction_write/upsert.rb', line 40

def action_request
  # changed attributes to persist
  changes = @attributes.dup
  changes = add_timestamps(changes, skip_created_at: true)
  changes_dumped = Dynamoid::Dumping.dump_attributes(changes, @model_class.attributes)

  # primary key to look up an item to update
  partition_key_dumped = dump(@model_class.hash_key, @hash_key)
  key = { @model_class.hash_key => partition_key_dumped }

  if @model_class.range_key?
    sort_key_dumped = dump(@model_class.range_key, @range_key)
    key[@model_class.range_key] = sort_key_dumped
  end

  # Build UpdateExpression and keep names and values placeholders mapping
  # in ExpressionAttributeNames and ExpressionAttributeValues.
  update_expression_statements = []
  expression_attribute_names = {}
  expression_attribute_values = {}

  changes_dumped.each_with_index do |(name, value), i|
    name_placeholder = "#_n#{i}"
    value_placeholder = ":_s#{i}"

    update_expression_statements << "#{name_placeholder} = #{value_placeholder}"
    expression_attribute_names[name_placeholder] = name
    expression_attribute_values[value_placeholder] = value
  end

  update_expression = "SET #{update_expression_statements.join(', ')}"

  {
    update: {
      key: key,
      table_name: @model_class.table_name,
      update_expression: update_expression,
      expression_attribute_names: expression_attribute_names,
      expression_attribute_values: expression_attribute_values
    }
  }
end