Allow to set DynamoDBEntryConversion per table (#3735)

Author: irina-herciu

generator/.DevConfigs/e5fd3631-e192-4dcb-931b-69d45722ae02.json

@@ -0,0 +1,11 @@
+{
+    "services": [
+        {
+            "serviceName": "DynamoDBv2",
+            "type": "patch",
+            "changeLogMessages": [
+                "Allow to set DynamoDBEntryConversion per table."
+            ]
+        }
+    ]
+}

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

@@ -30,42 +30,54 @@
 
 namespace Amazon.DynamoDBv2
 {
+
     /// <summary>
-    /// Available conversion schemas.
+    /// Specifies the conversion schema used to map the types to DynamoDB types.
+    /// This schema influences how items are serialized and deserialized when interacting with DynamoDB.
     /// </summary>
-    internal enum ConversionSchema
+    public enum ConversionSchema
     {
         /// <summary>
-        /// Default schema before 2014 L, M, BOOL, NULL support
-        /// 
-        /// The following .NET types are converted into the following DynamoDB types:
-        /// Number types (byte, int, float, decimal, etc.) are converted to N
-        /// String and char are converted to S
-        /// Bool is converted to N (0=false, 1=true)
-        /// DateTime and Guid are converto to S
-        /// MemoryStream and byte[] are converted to B
-        /// List, HashSet, and array of numerics types are converted to NS
-        /// List, HashSet, and array of string-based types are converted to SS
-        /// List, HashSet, and array of binary-based types are converted to BS
-        /// Dictionary{string,object} are converted to M
+        /// Indicates that no schema has been explicitly set.
+        /// </summary>
+        Unset = -1,
+
+        /// <summary>
+        /// Legacy conversion schema (and current default for context-level configurations).
+        ///
+        /// This schema pre-dates support for native DynamoDB types such as L (list), M (map), BOOL, and NULL.
+        /// Common .NET type mappings:
+        /// <ul>
+        /// <li><para>Number types (byte, int, float, decimal, etc.) → DynamoDB N (number)</para></li>
+        /// <li><para>string, char → S (string)</para></li>
+        /// <li><para>bool → N ("0" for false, "1" for true)</para></li>
+        /// <li><para>DateTime, Guid → S (string)</para></li>
+        /// <li><para>MemoryStream, byte[] → B (binary)</para></li>
+        /// <li><para>List, HashSet, array of numeric types → NS (number set)</para></li>
+        /// <li><para>List, HashSet, array of string types → SS (string set)</para></li>
+        /// <li><para>List, HashSet, array of binary types → BS (binary set)</para></li>
+        /// <li><para>Dictionary{string, object} → M (map)</para></li>
+        /// </ul>
         /// </summary>
         V1 = 0,
 
         /// <summary>
-        /// Schema fully supporting 2014 L, M, BOOL, NULL additions
+        /// Enhanced conversion schema that supports native DynamoDB types including L (list), M (map), BOOL, and NULL.
         /// 
-        /// The following .NET types are converted into the following DynamoDB types:
-        /// Number types (byte, int, float, decimal, etc.) are converted to N
-        /// String and char are converted to S
-        /// Bool is converted to BOOL
-        /// DateTime and Guid are converto to S
-        /// MemoryStream and byte[] are converted to B
-        /// HashSet of numerics types are converted to NS
-        /// HashSet of string-based types are converted to SS
-        /// HashSet of binary-based types are converted to BS
-        /// List and array of numerics, string-based types, and binary-based types
-        /// are converted to L type.
-        /// Dictionary{string,object} are converted to M
+        /// Common .NET type mappings:
+        /// <ul>
+        /// <li><para>Number types (byte, int, float, decimal, etc.) → DynamoDB N (number)</para></li>
+        /// <li><para>string, char → S (string)</para></li>
+        /// <li><para>bool → BOOL</para></li>
+        /// <li><para>DateTime, Guid → S (string)</para></li>
+        /// <li><para>MemoryStream, byte[] → B (binary)</para></li>
+        /// <li><para>HashSet of numeric types → NS (number set)</para></li>
+        /// <li><para>HashSet of string types → SS (string set)</para></li>
+        /// <li><para>HashSet of binary types → BS (binary set)</para></li>
+        /// <li><para>List, array (numeric, string, binary types) → L (list)</para></li>
+        /// <li><para>Dictionary{string, object} → M (map)</para></li>
+        /// </ul>
+        /// Recommended for applications that need full fidelity with native DynamoDB types.
         /// </summary>
         V2 = 1,
     }

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

@@ -52,22 +52,47 @@ public sealed class DynamoDBTableAttribute : DynamoDBAttribute
         /// </summary>
         public bool LowerCamelCaseProperties { get; set; }
 
+        /// <summary>
+        /// Gets and sets the <see cref="ConversionSchema"/> used for mapping between .NET and DynamoDB types.
+        /// 
+        /// The conversion schema determines how types are serialized and deserialized during data persistence. 
+        /// When resolving the effective schema, the following precedence is applied:
+        /// 1. If set on the operation configuration, it takes the highest precedence.
+        /// 2. If not set on the operation, but specified at the table level, the table configuration is used.
+        /// 3. If neither is set, the context-level configuration is used as the default fallback.
+        /// </summary>
+        public ConversionSchema Conversion { get; set; }
+
         /// <summary>
         /// Construct an instance of DynamoDBTableAttribute
         /// </summary>
         /// <param name="tableName"></param>
         public DynamoDBTableAttribute(string tableName)
-            : this(tableName, false) { }
+            : this(tableName, false, ConversionSchema.Unset)
+        {
+        }
 
         /// <summary>
         /// Construct an instance of DynamoDBTableAttribute
         /// </summary>
         /// <param name="tableName"></param>
         /// <param name="lowerCamelCaseProperties"></param>
         public DynamoDBTableAttribute(string tableName, bool lowerCamelCaseProperties)
+            : this(tableName, lowerCamelCaseProperties, ConversionSchema.Unset)
+        {
+        }
+
+        /// <summary>
+        /// Construct an instance of DynamoDBTableAttribute
+        /// </summary>
+        /// <param name="tableName"></param>
+        /// <param name="lowerCamelCaseProperties"></param>
+        /// <param name="conversion"></param>
+        public DynamoDBTableAttribute(string tableName, bool lowerCamelCaseProperties, ConversionSchema conversion)
         {
             TableName = tableName;
             LowerCamelCaseProperties = lowerCamelCaseProperties;
+            Conversion = conversion;
         }
     }
 

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

@@ -432,7 +432,7 @@ public DynamoDBFlatConfig(DynamoDBOperationConfig operationConfig, DynamoDBConte
             bool ignoreNullValues = operationConfig.IgnoreNullValues ?? contextConfig.IgnoreNullValues ?? false;
             bool retrieveDateTimeInUtc = operationConfig.RetrieveDateTimeInUtc ?? contextConfig.RetrieveDateTimeInUtc ?? true;
             bool isEmptyStringValueEnabled = operationConfig.IsEmptyStringValueEnabled ?? contextConfig.IsEmptyStringValueEnabled ?? false;
-            DynamoDBEntryConversion conversion = operationConfig.Conversion ?? contextConfig.Conversion ?? DynamoDBEntryConversion.CurrentConversion;
+            DynamoDBEntryConversion conversion = contextConfig.Conversion ?? DynamoDBEntryConversion.CurrentConversion;
             string tableNamePrefix = operationConfig.TableNamePrefix ?? contextConfig.TableNamePrefix ?? string.Empty;
 
             // These properties can only be set at the operation level
@@ -463,15 +463,16 @@ public DynamoDBFlatConfig(DynamoDBOperationConfig operationConfig, DynamoDBConte
             IndexName = indexName;
             QueryFilter = queryFilter;
             ConditionalOperator = conditionalOperator;
-            Conversion = conversion;
+            ContextConversion = conversion;
+            OperationConversion = operationConfig.Conversion;
             MetadataCachingMode = metadataCachingMode;
             DisableFetchingTableMetadata = disableFetchingTableMetadata;
             RetrieveDateTimeInUtc = retrieveDateTimeInUtc;
             DerivedTypeAttributeName = derivedTypeAttributeName;
 
             State = new OperationState();
         }
-
+        
         /// <summary>
         /// Property that directs DynamoDBContext to use consistent reads.
         /// If property is not set, behavior defaults to non-consistent reads.
@@ -552,10 +553,31 @@ public DynamoDBFlatConfig(DynamoDBOperationConfig operationConfig, DynamoDBConte
         public List<ScanCondition> QueryFilter { get; set; }
 
         /// <summary>
-        /// Conversion specification which controls how conversion between
+        /// Specifies the conversion behavior for .NET objects (entities) mapped to DynamoDB items.
+        /// 
+        /// This setting controls how conversion between .NET and DynamoDB types happens
+        /// on classes annotated with <see cref="DynamoDBTableAttribute"/>
+        /// </summary>
+        public DynamoDBEntryConversion ItemConversion { get; set; }
+
+        
+        /// <summary>
+        /// Operation Conversion specification which controls how conversion between
         /// .NET and DynamoDB types happens.
         /// </summary>
-        public DynamoDBEntryConversion Conversion { get; set; }
+        private DynamoDBEntryConversion OperationConversion { get; }
+
+        /// <summary>
+        /// Context Conversion specification which controls how conversion between
+        /// .NET and DynamoDB types happens.
+        /// </summary>
+        public DynamoDBEntryConversion Conversion => OperationConversion ?? ItemConversion ?? ContextConversion;
+
+        /// <summary>
+        /// Context Conversion specification which controls how conversion between
+        /// .NET and DynamoDB types happens.
+        /// </summary>
+        private DynamoDBEntryConversion ContextConversion { get; }
 
         /// <inheritdoc cref="DynamoDBContextConfig.DisableFetchingTableMetadata"/>
         public bool DisableFetchingTableMetadata { get; set; }
@@ -564,7 +586,7 @@ public DynamoDBFlatConfig(DynamoDBOperationConfig operationConfig, DynamoDBConte
         public bool RetrieveDateTimeInUtc { get; set; }
 
         // Checks if the IndexName is set on the config
-        internal bool IsIndexOperation { get { return !string.IsNullOrEmpty(IndexName); } }
+        internal bool IsIndexOperation => !string.IsNullOrEmpty(IndexName);
 
         // State of the operation using this config
         internal OperationState State { get; private set; }
@@ -584,6 +606,7 @@ public DynamoDBFlatConfig(DynamoDBOperationConfig operationConfig, DynamoDBConte
         /// </remarks>
         public string DerivedTypeAttributeName { get; set; }
 
+
         public class OperationState
         {
             private CircularReferenceTracking referenceTracking;

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

@@ -428,6 +428,9 @@ internal class ItemStorageConfig
         // indexName to GSIConfig mapping
         public Dictionary<string, GSIConfig> IndexNameToGSIMapping { get; set; }
 
+        // entity conversion
+        public DynamoDBEntryConversion Conversion { get; set; }
+
 
         public bool StorePolymorphicTypes => this.PolymorphicTypesStorageConfig.Any();
 
@@ -735,6 +738,10 @@ public ItemStorageConfig GetConfig([DynamicallyAccessedMembers(InternalConstants
 
                     if (tableCache.Cache.TryGetValue(actualTableName, out config))
                     {
+                        if (flatConfig == null)
+                            throw new ArgumentNullException("flatConfig");
+
+                        flatConfig.ItemConversion = config.Conversion;
                         return config;
                     }
                 }
@@ -759,6 +766,8 @@ public ItemStorageConfig GetConfig([DynamicallyAccessedMembers(InternalConstants
                     if (tableCache == null)
                     {
                         var baseStorageConfig = CreateStorageConfig(type, actualTableName: null, flatConfig);
+                        flatConfig.ItemConversion = baseStorageConfig.Conversion;
+
                         tableCache = new ConfigTableCache(baseStorageConfig);
                         Cache[type] = tableCache;
                     }
@@ -780,6 +789,7 @@ public ItemStorageConfig GetConfig([DynamicallyAccessedMembers(InternalConstants
                 }
 
                 config = CreateStorageConfig(type, actualTableName, flatConfig);
+                flatConfig.ItemConversion = config.Conversion;
                 tableCache.Cache[actualTableName] = config;
 
                 return config;
@@ -858,6 +868,13 @@ private static void PopulateConfigFromType(ItemStorageConfig config, [Dynamicall
                 if (string.IsNullOrEmpty(tableAttribute.TableName)) throw new InvalidOperationException("DynamoDBTableAttribute.Table is empty or null");
                 config.TableName = tableAttribute.TableName;
                 config.LowerCamelCaseProperties = tableAttribute.LowerCamelCaseProperties;
+
+                config.Conversion = tableAttribute.Conversion switch
+                {
+                    ConversionSchema.V1 => DynamoDBEntryConversion.V1,
+                    ConversionSchema.V2 => DynamoDBEntryConversion.V2,
+                    _ => config.Conversion
+                };
             }
 
             string tableAlias;

sdk/test/Services/DynamoDBv2/IntegrationTests/DataModelTests.cs

@@ -1114,6 +1114,45 @@ private void TestContextConversions()
 #pragma warning restore CS0618 // Re-enable the warning
             }
 
+            {
+
+#pragma warning disable CS0618 // Disable the warning for the deprecated DynamoDBContext constructors
+                ProductV2 productV2 = new ProductV2
+                {
+                    Id = 1,
+                    Name = "CloudSpotter",
+                    CompanyName = "CloudsAreGrate",
+                    Price = 1200,
+                    TagSet = new HashSet<string> { "Prod", "1.0" },
+                    CurrentStatus = Status.Active,
+                    FormerStatus = Status.Upcoming,
+                    Supports = Support.Unix | Support.Windows,
+                    PreviousSupport = null,
+                    InternalId = "T1000",
+                    IsPublic = true,
+                    AlwaysN = true,
+                    Rating = 4,
+                    Components = new List<string> { "Code", "Coffee" },
+                    KeySizes = new List<byte> { 16, 64, 128 },
+                    CompanyInfo = new CompanyInfo
+                    {
+                        Name = "MyCloud",
+                        Founded = new DateTime(1994, 7, 6),
+                        Revenue = 9001
+                    }
+                };
+              
+                using (var contextV1 = new DynamoDBContext(Client, new DynamoDBContextConfig { Conversion = conversionV1 }))
+                {
+                    var docV1 = contextV1.ToDocument(productV2, new ToDocumentConfig { Conversion = conversionV1 });
+                    var docV2 = contextV1.ToDocument(productV2, new ToDocumentConfig { });
+                    VerifyConversions(docV1, docV2);
+                }
+
+#pragma warning restore CS0618 // Re-enable the warning
+
+            }
+
             // Introduce a circular reference and try to serialize
             {
                 product.CompanyInfo = new CompanyInfo
@@ -2632,6 +2671,11 @@ public object FromEntry(DynamoDBEntry entry)
             }
         }
 
+        [DynamoDBTable("HashTable", false, ConversionSchema.V2)]
+        public class ProductV2 : Product
+        {
+        }
+
         /// <summary>
         /// Class representing items in the table [TableNamePrefix]HashTable
         /// </summary>