Datetime handling - updated default for DynamoDB data model to return UTC by default.

Author: boblodgett

sdk/src/Services/DynamoDBv2/Custom/AWSConfigs.DynamoDB.cs

@@ -170,8 +170,9 @@ public partial class DynamoDBContextConfig
         /// <summary>
         /// If true, all <see cref="DateTime"/> properties are retrieved in UTC timezone while reading data from DynamoDB. Else, the local timezone is used.
         /// </summary>
-        /// <remarks>This setting is only applicable to the high-level library. Service calls made via <see cref="AmazonDynamoDBClient"/> will always return <see cref="DateTime"/> attributes in UTC.</remarks>
-        public bool? RetrieveDateTimeInUtc { get; set; }
+        /// <remarks>This setting is only applicable to the high-level library. Service calls made via <see cref="AmazonDynamoDBClient"/> will always 
+        /// return <see cref="DateTime"/> attributes in UTC. The default is true to return datetimes in UTC format.</remarks>
+        public bool? RetrieveDateTimeInUtc { get; set; } = true;
 
         /// <summary>
         /// Adds a TableAlias to the TableAliases property.

sdk/src/Services/DynamoDBv2/Custom/Conversion/SchemaV1.cs

@@ -252,11 +252,11 @@ protected override bool TryTo(DateTime value, out Primitive p)
         }
         protected override bool TryFrom(Primitive p, Type targetType, out DateTime result)
         {
-            if (DateTime.TryParseExact(p.StringValue, AWSSDKUtils.ISO8601DateFormat, CultureInfo.InvariantCulture, DateTimeStyles.AssumeUniversal, out result))
+            if (DateTime.TryParseExact(p.StringValue, AWSSDKUtils.ISO8601DateFormat, CultureInfo.InvariantCulture, DateTimeStyles.AssumeUniversal | DateTimeStyles.AdjustToUniversal, out result))
             {
                 return true;
             }
-            return DateTime.TryParse(p.StringValue, CultureInfo.InvariantCulture, DateTimeStyles.AssumeUniversal, out result);
+            return DateTime.TryParse(p.StringValue, CultureInfo.InvariantCulture, DateTimeStyles.AssumeUniversal | DateTimeStyles.AdjustToUniversal, out result);
         }
     }
 

sdk/src/Services/DynamoDBv2/Custom/DataModel/ContextInternal.cs

@@ -475,15 +475,15 @@ private object FromDynamoDBEntry(SimplePropertyStorage propertyStorage, DynamoDB
             if (conversion.HasConverter(targetType))
             {
                 var output = conversion.ConvertFromEntry(targetType, entry);
-                if (flatConfig.RetrieveDateTimeInUtc)
+                if (!flatConfig.RetrieveDateTimeInUtc)
                 {
                     if (targetType == typeof(DateTime))
                     {
-                        return ((DateTime)output).ToUniversalTime();
+                        return ((DateTime)output).ToLocalTime();
                     }
                     else if (targetType == typeof(DateTime?))
                     {
-                        return ((DateTime?)output)?.ToUniversalTime();
+                        return ((DateTime?)output)?.ToLocalTime();
                     }
                 }
                 return output;

sdk/test/NetStandard/IntegrationTests/IntegrationTests/DynamoDB/DataModelTests.cs

@@ -383,8 +383,7 @@ private async Task TestHashObjects()
                 Assert.Equal(product.KeySizes.Count, retrieved.KeySizes.Count);
                 Assert.NotNull(retrieved.CompanyInfo);
                 Assert.Equal(product.CompanyInfo.Name, retrieved.CompanyInfo.Name);
-                //TODO: this is coming back in UTC but the original is DateTimeKind.Unspecified
-                Assert.Equal(product.CompanyInfo.Founded, retrieved.CompanyInfo.Founded);
+                Assert.Equal(product.CompanyInfo.Founded.ToUniversalTime(), retrieved.CompanyInfo.Founded);
                 Assert.NotEqual(product.CompanyInfo.Revenue, retrieved.CompanyInfo.Revenue);
                 Assert.Equal(product.CompanyInfo.AllProducts.Count, retrieved.CompanyInfo.AllProducts.Count);
                 Assert.Equal(product.CompanyInfo.AllProducts[0].Id, retrieved.CompanyInfo.AllProducts[0].Id);