Azure Table StorageをRESTで

アクセスするサンプル(ASP.NET)。
MSDNのAuthentication Schemesの項目でSharedKeyLiteの記述の理解に苦戦した。

using System;

using System.Net;

using System.IO;

using System.Text;

using System.Globalization;

using System.Security.Cryptography;
namespace WebRole1

{

    public partial class _Default : System.Web.UI.Page

    {

        public string tableEndPoint { get; set; }

        public string accountName { get; set; }

        public string sharedKey { get; set; }

        private string msVersion = "2009-09-19";
        protected void Button1_Click(object sender, EventArgs e)

        {

            this.tableEndPoint = "http://127.0.0.1:10002/devstoreaccount1/";

            this.accountName = "devstoreaccount1";

            this.sharedKey = "Eby8vdM02xNOcqFlqUwJPLlmEtlCDXJ1OUzFT50uSRZ6IFsuFq2UVErCz4I6tq/K1SZFPTOtr/KBHBeksoGMGw==";
            TextBox1.Text = GetEntity("SampleTable", "87743227-da94-41c2-b266-358a46072dfd", "11e48305-6284-4c79-b657-0d8a64859282");

        }
        private string GetEntity(String tableName, String partitionKey, String rowKey)

        {

            string path = String.Format("{0}(PartitionKey='{1}',RowKey='{2}')", tableName, partitionKey, rowKey);

            Uri uri = new Uri(this.tableEndPoint + path);

            string dateInRfc1123Format = DateTime.UtcNow.ToString("R");

            string authorizationHeader = CreateAuthorizationSharedKeyLiteHeader(uri.AbsolutePath, dateInRfc1123Format);
            HttpWebRequest request = (HttpWebRequest)WebRequest.Create(uri);

            request.Method = "GET";

            request.Headers.Add("x-ms-date", dateInRfc1123Format);

            request.Headers.Add("x-ms-version", this.msVersion);

            request.Headers.Add("Authorization", authorizationHeader);

            request.Headers.Add("Accept-Charset", "UTF-8");

            request.Headers.Add("DataServiceVersion", "1.0;NetFx");

            request.Headers.Add("MaxDataServiceVersion", "1.0;NetFx");

            request.Accept = "application/atom+xml,application/xml";

            //request.UserAgent = "Microsoft ADO.NET Data Services";
            using (HttpWebResponse response = (HttpWebResponse)request.GetResponse())

            {

                Stream dataStream = response.GetResponseStream();

                using (StreamReader reader = new StreamReader(dataStream))

                {

                    return reader.ReadToEnd();

                }

            }

        }
        private string CreateAuthorizationSharedKeyLiteHeader(string canonicalizedResource, string date)

        {

            string tosign = date + "\n/" + this.accountName + canonicalizedResource;

            string sig = MacSha(tosign, Convert.FromBase64String(this.sharedKey));
            return string.Format(CultureInfo.InvariantCulture, "{0} {1}:{2}", "SharedKeyLite", this.accountName, sig);

        }
        private static string MacSha(string canonicalizedString, byte[] key)

        {

            byte[] dataToMac = Encoding.UTF8.GetBytes(canonicalizedString);

            using (HMACSHA256 hmacsha1 = new HMACSHA256(key))

            {

                return Convert.ToBase64String(hmacsha1.ComputeHash(dataToMac));

            }

        }

    }

}

動作確認はDevelopment Fabricのみで実クラウドでは未確認。
参考:
MSDN Forum > Microsoft Visual Studio 2010 Beta 2 Forums > Windows Azure
Insert Entity (Azure Table Storage)
http://social.msdn.microsoft.com/Forums/en/windowsazure/thread/41578289-cfe2-41f1-94f0-c771da0aa84c