OLE Data Extraction from Specific Drawing Object at Amazon S3 Storage

SaasposeApp.AppKey = "9a******************";
            SaasposeApp.AppSID = "77*********************";
            //specify product URI
            Product.BaseProductUri = @"api*saaspose*com/v1.0";
            try
            {
                int drawingObjectIndex = 1;
                string fileName = "SampleDrawingObject.doc";
                string saveFormat = "xls"; //Choose from jpeg, tiff, png and bmp
                string outputFile = "C:\\OutputDrawingObject." + saveFormat;
                string amazonS3StorageName = "MyAmazonS3Storage";
                string amazonS3BucketName = "MyS3Bucket"; // include folder name if file is not at root folder 

                //build URI
                string strURI = Product.BaseProductUri + "/words/" + fileName + "/drawingObjects/" + drawingObjectIndex;
                strURI += "/oleData?storage=" + amazonS3StorageName + "&folder=" + amazonS3BucketName;

                //sign URI
                string signedURI = Sign(strURI);

                //get response stream
                Stream responseStream = ProcessCommand(signedURI, "GET");

                using (Stream fileStream = System.IO.File.OpenWrite(outputFile))
                {
                    CopyStream(responseStream, fileStream);
                }
                responseStream.Close();
            }
            catch (Exception ex)
            {
                Console.WriteLine(ex.Message);
            } 

//Following are the required methods and classes 

        public static string Sign(string url)
        {
            try
            {
                // Add appSID parameter.
                UriBuilder builder = new UriBuilder(url);
                if (builder.Query != null && builder.Query.Length > 1)
                    builder.Query = builder.Query.Substring(1) + "&appSID=" + SaasposeApp.AppSID;
                else
                    builder.Query = "appSID=" + SaasposeApp.AppSID;
                // Remove final slash here as it can be added automatically.
                builder.Path = builder.Path.TrimEnd('/');
                // Compute the hash.

                byte[] privateKey = System.Text.Encoding.UTF8.GetBytes(SaasposeApp.AppKey);

                System.Security.Cryptography.HMACSHA1 algorithm = new System.Security.Cryptography.HMACSHA1(privateKey);
                //System.Text.ASCIIEncoding
                byte[] sequence = System.Text.ASCIIEncoding.ASCII.GetBytes(builder.Uri.AbsoluteUri);
                byte[] hash = algorithm.ComputeHash(sequence);
                string signature = Convert.ToBase64String(hash);
                // Remove invalid symbols.
                signature = signature.TrimEnd('=');
                signature = System.Web.HttpUtility.UrlEncode(signature);
                // Convert codes to upper case as they can be updated automatically.
                signature = System.Text.RegularExpressions.Regex.Replace(signature, "%[0-9a-f]{2}", e => e.Value.ToUpper());

                // Add the signature to query string.
                return string.Format("{0}&signature={1}", builder.Uri.AbsoluteUri, signature);
            }
            catch (Exception ex)
            {
                throw new Exception(ex.Message);
            }
        }
        public static Stream ProcessCommand(string strURI, string strHttpCommand)
        {
            try
            {
                Uri address = new Uri(strURI);
                System.Net.HttpWebRequest request = (System.Net.HttpWebRequest)System.Net.HttpWebRequest.Create(address);
                request.Method = strHttpCommand;
                request.ContentType = "application/json";
                request.ContentLength = 0;
                System.Net.HttpWebResponse response = (System.Net.HttpWebResponse)request.GetResponse();
                return response.GetResponseStream();
            }
            catch (System.Net.WebException webex)
            {
                throw new Exception(webex.Message);
            }
            catch (Exception Ex)
            {
                throw new Exception(Ex.Message);
            }
        }

        public static void CopyStream(Stream input, Stream output)
        {
            try
            {
                byte[] buffer = new byte[8 * 1024];
                int len;
                while ((len = input.Read(buffer, 0, buffer.Length)) > 0)
                {
                    output.Write(buffer, 0, len);
                }
            }
            catch (Exception ex)
            {
                throw new Exception(ex.Message);
            }
        }
    }


    public class Product
    {
public static string BaseProductUri { get; set; }
    }
    public class SaasposeApp
    {
public static string AppSID { get; set; }
public static string AppKey { get; set; }
    }