Add Epoch Time Attribute Type

CHANGELOG.md

@@ -1,6 +1,8 @@
 Unreleased Changes
 ------------------
 
+* Feature - Aws::Record::Marshalers::EpochTimeMarshaler - Adds the `epoch_time_attr`, which behaves much like `time_attr` except the Amazon DynamoDB storage type is numeric, and the serialized value is epoch seconds.
+
 2.1.0 (2018-06-25)
 ------------------
 

lib/aws-record.rb

@@ -34,6 +34,7 @@
 require_relative 'aws-record/record/marshalers/date_marshaler'
 require_relative 'aws-record/record/marshalers/date_time_marshaler'
 require_relative 'aws-record/record/marshalers/time_marshaler'
+require_relative 'aws-record/record/marshalers/epoch_time_marshaler'
 require_relative 'aws-record/record/marshalers/list_marshaler'
 require_relative 'aws-record/record/marshalers/map_marshaler'
 require_relative 'aws-record/record/marshalers/string_set_marshaler'

lib/aws-record/record/attributes.rb

@@ -240,6 +240,28 @@ def time_attr(name, opts = {})
           attr(name, Marshalers::TimeMarshaler.new(opts), opts)
         end
 
+        # Define a time-type attribute for your model which persists as
+        #   epoch-seconds.
+        #
+        # @param [Symbol] name Name of this attribute.  It should be a name
+        #   that is safe to use as a method.
+        # @param [Hash] opts
+        # @option opts [Boolean] :hash_key Set to true if this attribute is
+        #   the hash key for the table.
+        # @option opts [Boolean] :range_key Set to true if this attribute is
+        #   the range key for the table.
+        # @option opts [Boolean] :persist_nil Optional attribute used to
+        #   indicate whether nil values should be persisted. If true, explicitly
+        #   set nil values will be saved to DynamoDB as a "null" type. If false,
+        #   nil values will be ignored and not persisted. By default, is false.
+        # @option opts [Object] :default_value Optional attribute used to
+        #   define a "default value" to be used if the attribute's value on an
+        #   item is nil or not set at persistence time.
+        def epoch_time_attr(name, opts = {})
+          opts[:dynamodb_type] = "N"
+          attr(name, Marshalers::EpochTimeMarshaler.new(opts), opts)
+        end
+
         # Define a list-type attribute for your model.
         #
         # Lists do not have to be homogeneous, but they do have to be types that

lib/aws-record/record/marshalers/epoch_time_marshaler.rb

@@ -0,0 +1,66 @@
+# Copyright 2018 Amazon.com, Inc. or its affiliates. All Rights Reserved.
+#
+# Licensed under the Apache License, Version 2.0 (the "License"). You may not
+# use this file except in compliance with the License. A copy of the License is
+# located at
+#
+#     http://aws.amazon.com/apache2.0/
+#
+# or in the "license" file accompanying this file. This file is distributed on
+# an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express
+# or implied. See the License for the specific language governing permissions
+# and limitations under the License.
+
+require 'time'
+
+module Aws
+  module Record
+    module Marshalers
+
+      class EpochTimeMarshaler
+        def initialize(opts = {})
+          @use_local_time = opts[:use_local_time] ? true : false
+        end
+
+        def type_cast(raw_value)
+          value = _format(raw_value)
+          if !@use_local_time && value.is_a?(::Time)
+            value.utc
+          else
+            value
+          end
+        end
+
+        def serialize(raw_value)
+          time = type_cast(raw_value)
+          if time.nil?
+            nil
+          elsif time.is_a?(::Time)
+            time.to_i
+          else
+            msg = "expected a Time value or nil, got #{time.class}"
+            raise ArgumentError, msg
+          end
+        end
+
+        private
+
+        def _format(raw_value)
+          case raw_value
+          when nil
+            nil
+          when ''
+            nil
+          when ::Time
+            raw_value
+          when Integer # timestamp
+            ::Time.at(raw_value)
+          else # Date, DateTime, or String
+            ::Time.parse(raw_value.to_s)
+          end
+        end
+      end
+
+    end
+  end
+end

spec/aws-record/record/item_operations_spec.rb

@@ -32,6 +32,7 @@ module Record
           map_attr(:map_nil_as_nil, persist_nil: true)
           map_attr(:map_no_nil_persist)
           boolean_attr(:bool, database_attribute_name: "my_boolean")
+          epoch_time_attr(:ttl)
         end
       end
 
@@ -54,6 +55,7 @@ module Record
           item.id = 1
           item.date = '2015-12-14'
           item.body = 'Hello!'
+          item.ttl = Time.parse("2018-07-09 22:02:12 UTC")
           item.save!
           expect(api_requests).to eq([{
             table_name: "TestTable",
@@ -62,7 +64,8 @@ module Record
               "MyDate" => { s: "2015-12-14" },
               "body" => { s: "Hello!" },
               "list_nil_to_empty" => { l: [] },
-              "map_nil_to_empty" => { m: {} }
+              "map_nil_to_empty" => { m: {} },
+              "ttl" => { n: "1531173732" },
             },
             condition_expression: "attribute_not_exists(#H)"\
               " and attribute_not_exists(#R)",

spec/aws-record/record/marshalers/epoch_time_marshaler_spec.rb

@@ -0,0 +1,97 @@
+# Copyright 2016 Amazon.com, Inc. or its affiliates. All Rights Reserved.
+#
+# Licensed under the Apache License, Version 2.0 (the "License"). You may not
+# use this file except in compliance with the License. A copy of the License is
+# located at
+#
+#     http://aws.amazon.com/apache2.0/
+#
+# or in the "license" file accompanying this file. This file is distributed on
+# an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express
+# or implied. See the License for the specific language governing permissions
+# and limitations under the License.
+
+require 'spec_helper'
+require 'time'
+
+module Aws
+  module Record
+    module Marshalers
+      describe EpochTimeMarshaler do
+
+        context 'default settings' do
+          before(:each) do
+            @marshaler = EpochTimeMarshaler.new
+          end
+
+          describe 'type casting' do
+            it 'casts nil and empty string as nil' do
+              expect(@marshaler.type_cast(nil)).to be_nil
+              expect(@marshaler.type_cast('')).to be_nil
+            end
+
+            it 'passes through Time objects' do
+              expected = Time.at(1531173732)
+              input = Time.at(1531173732)
+              expect(@marshaler.type_cast(input)).to eq(expected)
+            end
+
+            it 'converts timestamps to Time' do
+              expected = Time.at(1531173732)
+              input = 1531173732
+              expect(@marshaler.type_cast(input)).to eq(expected)
+            end
+
+            it 'converts DateTimes to Time' do
+              expected = Time.parse("2009-02-13 23:31:30 UTC")
+              input = DateTime.parse("2009-02-13 23:31:30 UTC")
+              expect(@marshaler.type_cast(input)).to eq(expected)
+            end
+
+            it 'converts strings to Time' do
+              expected = Time.parse("2009-02-13 23:31:30 UTC")
+              input = "2009-02-13 23:31:30 UTC"
+              expect(@marshaler.type_cast(input)).to eq(expected)
+            end
+
+            it 'converts automatically to utc' do
+              expected = Time.parse("2016-07-20 23:31:10 UTC")
+              input = "2016-07-20 16:31:10 -0700"
+              expect(@marshaler.type_cast(input)).to eq(expected)
+            end
+
+            it 'raises when unable to parse as a Time' do
+              expect {
+                @marshaler.type_cast("that time when")
+              }.to raise_error(ArgumentError)
+            end
+          end
+
+          describe 'serialization for storage' do
+            it 'serializes nil as null' do
+              expect(@marshaler.serialize(nil)).to eq(nil)
+            end
+
+            it 'serializes Time in epoch seconds' do
+              t = Time.parse('2018-07-09 22:02:12 UTC')
+              expect(@marshaler.serialize(t)).to eq(1531173732)
+            end
+          end
+        end
+
+        context "use local time" do
+          before(:each) do
+            @marshaler = TimeMarshaler.new(use_local_time: true)
+          end
+
+          it 'does not automatically convert to utc' do
+            expected = Time.parse("2016-07-20 16:31:10 -0700")
+            input = "2016-07-20 16:31:10 -0700"
+            expect(@marshaler.type_cast(input)).to eq(expected)
+          end
+        end
+
+      end
+    end
+  end
+end