Add ToJson for DynamoDBEvent

Libraries/src/Amazon.Lambda.DynamoDBEvents/Amazon.Lambda.DynamoDBEvents.csproj

@@ -6,7 +6,7 @@
     <TargetFrameworks>netcoreapp3.1;net8.0</TargetFrameworks>
     <Description>Amazon Lambda .NET Core support - DynamoDBEvents package.</Description>
     <AssemblyTitle>Amazon.Lambda.DynamoDBEvents</AssemblyTitle>
-    <VersionPrefix>3.0.0</VersionPrefix>
+    <VersionPrefix>3.1.0</VersionPrefix>
     <AssemblyName>Amazon.Lambda.DynamoDBEvents</AssemblyName>
     <PackageId>Amazon.Lambda.DynamoDBEvents</PackageId>
     <PackageTags>AWS;Amazon;Lambda</PackageTags>

Libraries/src/Amazon.Lambda.DynamoDBEvents/ExtensionMethods.cs

@@ -0,0 +1,157 @@
+using System.Collections.Generic;
+using System.IO;
+using System.Text;
+using System.Text.Json;
+using static Amazon.Lambda.DynamoDBEvents.DynamoDBEvent;
+
+namespace Amazon.Lambda.DynamoDBEvents
+{
+    /// <summary>
+    /// Extension methods for working with <see cref="DynamoDBEvent"/>
+    /// </summary>
+    public static class ExtensionMethods
+    {
+        /// <summary>
+        /// Converts a dictionary representing a DynamoDB item to a JSON string.
+        /// This may be useful when casting a DynamoDB Lambda event to the AWS SDK's 
+        /// higher-level document and object persistence classes.
+        /// </summary>
+        /// <param name="item">Dictionary representing a DynamoDB item</param>
+        /// <returns>Unformatted JSON string representing the DynamoDB item</returns>
+        public static string ToJson(this Dictionary<string, AttributeValue> item)
+        {
+            return ToJson(item, false);
+        }
+
+        /// <summary>
+        /// Converts a dictionary representing a DynamoDB item to a JSON string.
+        /// This may be useful when casting a DynamoDB Lambda event to the AWS SDK's 
+        /// higher-level document and object persistence classes.
+        /// </summary>
+        /// <param name="item">Dictionary representing a DynamoDB item</param>
+        /// <returns>Formatted JSON string representing the DynamoDB item</returns>
+        public static string ToJsonPretty(this Dictionary<string, AttributeValue> item)
+        {
+            return ToJson(item, true);
+        }
+
+        /// <summary>
+        /// Internal entry point for converting a dictionary representing a DynamoDB item to a JSON string.
+        /// </summary>
+        /// <param name="item">Dictionary representing a DynamoDB item</param>
+        /// <param name="prettyPrint">Whether the resulting JSON should be formatted</param>
+        /// <returns>JSON string representing the DynamoDB item</returns>
+        private static string ToJson(Dictionary<string, AttributeValue> item, bool prettyPrint)
+        {
+            if (item == null || item.Count == 0)
+            {
+                return "{}";
+            }
+
+            using var stream = new MemoryStream();
+            using var writer = new Utf8JsonWriter(stream, new JsonWriterOptions { Indented = prettyPrint});
+
+            WriteJson(writer, item);
+
+            writer.Flush();
+            return Encoding.UTF8.GetString(stream.ToArray());
+        }
+
+        /// <summary>
+        /// Writes a single DynamoDB attribute as a json. May be called recursively for maps.
+        /// </summary>
+        /// <param name="writer">JSON writer</param>
+        /// <param name="item">Dictionary representing a DynamoDB item, or a map within an item</param>
+        private static void WriteJson(Utf8JsonWriter writer, Dictionary<string, AttributeValue> item)
+        {
+            writer.WriteStartObject();
+
+            foreach (var attribute in item)
+            {
+                writer.WritePropertyName(attribute.Key);
+                WriteJsonValue(writer, attribute.Value);
+            }
+
+            writer.WriteEndObject();
+        }
+
+        /// <summary>
+        /// Writes a single DynamoDB attribute value as a json value
+        /// </summary>
+        /// <param name="writer">JSON writer</param>
+        /// <param name="attribute">DynamoDB attribute</param>
+        private static void WriteJsonValue(Utf8JsonWriter writer, AttributeValue attribute)
+        {
+            if (attribute.S != null)
+            {
+                writer.WriteStringValue(attribute.S);
+            }
+            else if (attribute.N != null)
+            {
+#if NETCOREAPP3_1  // WriteRawValue was added in .NET 6, but we need to write out Number values without quotes
+                using var document = JsonDocument.Parse(attribute.N);
+                document.WriteTo(writer);
+#else
+                writer.WriteRawValue(attribute.N);
+#endif
+            }
+            else if (attribute.B != null)
+            {
+                writer.WriteBase64StringValue(attribute.B.ToArray());
+            }
+            else if (attribute.BOOL != null)
+            {
+                writer.WriteBooleanValue(attribute.BOOL.Value);
+            }
+            else if (attribute.NULL != null)
+            {
+                writer.WriteNullValue();
+            }
+            else if (attribute.M != null)
+            {
+                WriteJson(writer, attribute.M);
+            }
+            else if (attribute.L != null)
+            {
+                writer.WriteStartArray();
+                foreach (var item in attribute.L)
+                {
+                    WriteJsonValue(writer, item);
+                }
+                writer.WriteEndArray();
+            }
+            else if (attribute.SS != null)
+            {
+                writer.WriteStartArray();
+                foreach (var item in attribute.SS)
+                {
+                    writer.WriteStringValue(item);
+                }
+                writer.WriteEndArray();
+            }
+            else if (attribute.NS != null)
+            {
+                writer.WriteStartArray();
+                foreach (var item in attribute.NS)
+                {
+#if NETCOREAPP3_1  // WriteRawValue was added in .NET 6, but we need to write out Number values without quotes
+                    using var document = JsonDocument.Parse(item);
+                    document.WriteTo(writer);
+#else
+                    writer.WriteRawValue(item);
+#endif
+                }
+                writer.WriteEndArray();
+            }
+            else if (attribute.BS != null)
+            {
+                writer.WriteStartArray();
+                foreach (var item in attribute.BS)
+                {
+                    writer.WriteBase64StringValue(item.ToArray());
+                }
+                writer.WriteEndArray();
+            }
+        }
+    }
+}

Libraries/test/EventsTests.NET6/EventsTests.NET6.csproj

@@ -5,6 +5,7 @@
     <PackageId>EventsTests31</PackageId>
     <GenerateRuntimeConfigurationFiles>true</GenerateRuntimeConfigurationFiles>
     <RootNamespace>EventsTests.NET6</RootNamespace>
+    <LangVersion>latest</LangVersion>
   </PropertyGroup>
 
 
@@ -54,13 +55,14 @@
   </ItemGroup>
 
   <ItemGroup>
+    <PackageReference Include="AWSSDK.DynamoDBv2" Version="3.7.301.14" />
     <PackageReference Include="Microsoft.NET.Test.Sdk" Version="17.0.0" />
     <PackageReference Include="xunit.runner.visualstudio" Version="2.4.3">
       <PrivateAssets>all</PrivateAssets>
       <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>
     </PackageReference>
     <PackageReference Include="xunit" Version="2.4.1" />
-    <PackageReference Include="AWSSDK.Core" Version="3.7.10.9" />
+    <PackageReference Include="AWSSDK.Core" Version="3.7.302.13" />
   </ItemGroup>
 
   <ItemGroup>

Libraries/test/EventsTests.NETCore31/EventsTests.NETCore31.csproj

@@ -6,6 +6,7 @@
     <GenerateRuntimeConfigurationFiles>true</GenerateRuntimeConfigurationFiles>
     <RuntimeIdentifiers>win7-x64;win7-x86</RuntimeIdentifiers>
     <RootNamespace>EventsTests31</RootNamespace>
+    <LangVersion>latest</LangVersion>
   </PropertyGroup>
 
 
@@ -54,10 +55,11 @@
   </ItemGroup>
 
   <ItemGroup>
+    <PackageReference Include="AWSSDK.DynamoDBv2" Version="3.7.301.14" />
     <PackageReference Include="Microsoft.NET.Test.Sdk" Version="15.0.0" />
     <PackageReference Include="xunit.runner.visualstudio" Version="2.2.0" />
     <PackageReference Include="xunit" Version="2.2.0" />
-    <PackageReference Include="AWSSDK.Core" Version="3.7.10.9" />
+    <PackageReference Include="AWSSDK.Core" Version="3.7.302.13" />
   </ItemGroup>
 
   <ItemGroup>