Example: Handling Binary Type Attributes Using the AWS SDK for .NET Low-Level API

using System;
using System.Collections.Generic;
using System.IO;
using System.IO.Compression;
using Amazon.DynamoDBv2;
using Amazon.DynamoDBv2.Model;
using Amazon.Runtime;

namespace Amazon.DynamoDBv2.Documentation
{
  class Program
  {
    private static string tableName = "Reply";
    private static AmazonDynamoDBClient client;

    static void Main(string[] args)
    {
      // Reply table primary key.
      string replyIdHashAttribute = "Amazon DynamoDB#DynamoDB Thread 1";
      string replyDateTimeRangeAttribute = Convert.ToString(DateTime.UtcNow);

      var config = new AmazonDynamoDBConfig();
      config.ServiceURL = System.Configuration.ConfigurationManager.AppSettings["ServiceURL"];
      client = new AmazonDynamoDBClient(config);

      try
      {
        CreateItem(replyIdHashAttribute, replyDateTimeRangeAttribute);
        RetrieveItem(replyIdHashAttribute, replyDateTimeRangeAttribute);
        // Delete item.
        DeleteItem(replyIdHashAttribute, replyDateTimeRangeAttribute);
        Console.WriteLine("To continue, press Enter");
        Console.ReadLine();
      }
      catch (AmazonDynamoDBException e) { Console.WriteLine(e.Message); }
      catch (AmazonServiceException e) { Console.WriteLine(e.Message); }
      catch (Exception e) { Console.WriteLine(e.Message); }
    }

    private static void CreateItem(string hashAttribute, string rangeAttribute)
    {
      MemoryStream compressedMessage = ToGzipMemoryStream("Some long extended message to compress.");
      var request = new PutItemRequest
      {
        TableName = tableName,
        Item = new Dictionary<string, AttributeValue>()
        {
          { "Id", new AttributeValue { S = hashAttribute }},
          { "ReplyDateTime", new AttributeValue { S = rangeAttribute }},
          { "Subject", new AttributeValue { S = "Binary type " }},
          { "Message", new AttributeValue { S = "Some message about the binary type" }},
          { "ExtendedMessage", new AttributeValue { B = compressedMessage }}
        }
      };
      client.PutItem(request);
    }

    private static void RetrieveItem(string hashAttribute, string rangeAttribute)
    {
      var request = new GetItemRequest
      {
        TableName = tableName,
        Key = new Dictionary<string, AttributeValue>()
        {
          { "Id", new AttributeValue { S = hashAttribute } },
          { "ReplyDateTime", new AttributeValue { S = rangeAttribute } }
        },
        ConsistentRead = true
      };
      var response = client.GetItem(request);

      // Check the response.
      var result = response.GetItemResult;
      var attributeList = result.Item; // attribute list in the response.
      Console.WriteLine("\nPrinting item after retrieving it ............");

      PrintItem(attributeList);
    }

    private static void DeleteItem(string hashAttribute, string rangeAttribute)
    {
      var request = new DeleteItemRequest
      {
        TableName = tableName,
        Key = new Dictionary<string, AttributeValue>()
        {
          { "Id", new AttributeValue { S = hashAttribute } },
          { "ReplyDateTime", new AttributeValue { S = rangeAttribute } }
        }
      };
      var response = client.DeleteItem(request);

      // Check the response.
      var result = response.DeleteItemResult;
    }

    private static void PrintItem(Dictionary<string, AttributeValue> attributeList)
    {
      foreach (KeyValuePair<string, AttributeValue> kvp in attributeList)
      {
        string attributeName = kvp.Key;
        AttributeValue value = kvp.Value;

        Console.WriteLine(
            attributeName + " " +
            (value.S == null ? "" : "S=[" + value.S + "]") +
            (value.N == null ? "" : "N=[" + value.N + "]") +
            (value.SS == null ? "" : "SS=[" + string.Join(",", value.SS.ToArray()) + "]") +
            (value.NS == null ? "" : "NS=[" + string.Join(",", value.NS.ToArray()) + "]") +
            (value.B == null ? "" : "B=[" + FromGzipMemoryStream(value.B) + "]")
        );
      }
      Console.WriteLine("************************************************");
    }

    private static MemoryStream ToGzipMemoryStream(string value)
    {
      MemoryStream output = new MemoryStream();
      using (GZipStream zipStream = new GZipStream(output, CompressionMode.Compress, true))
      using (StreamWriter writer = new StreamWriter(zipStream))
      {
        writer.Write(value);
      }
      return output;
    }

    private static string FromGzipMemoryStream(MemoryStream stream)
    {
      using (GZipStream zipStream = new GZipStream(stream, CompressionMode.Decompress))
      using (StreamReader reader = new StreamReader(zipStream))
      {
        return reader.ReadToEnd();
      }
    }

  }
}