/WP7.0/BabelCam/C#/Libraries/WindowsPhoneCloud.StorageClient.C#/Credentials/StorageCredentialsAccountAndKey.cs

// ----------------------------------------------------------------------------------

// Microsoft Developer & Platform Evangelism

// 

// Copyright (c) Microsoft Corporation. All rights reserved.

// 

// THIS CODE AND INFORMATION ARE PROVIDED "AS IS" WITHOUT WARRANTY OF ANY KIND, 

// EITHER EXPRESSED OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE IMPLIED WARRANTIES 

// OF MERCHANTABILITY AND/OR FITNESS FOR A PARTICULAR PURPOSE.

// ----------------------------------------------------------------------------------

// The example companies, organizations, products, domain names,

// e-mail addresses, logos, people, places, and events depicted

// herein are fictitious.  No association with any real company,

// organization, product, domain name, email address, logo, person,

// places, or events is intended or should be inferred.

// ----------------------------------------------------------------------------------



namespace Microsoft.Samples.WindowsPhoneCloud.StorageClient.Credentials

{

    using System;

    using System.Collections.Generic;

    using System.Data.Services.Client;

    using System.Globalization;

    using System.Net;

    using System.Security.Cryptography;

    using System.Text;

    

    public class StorageCredentialsAccountAndKey : IStorageCredentials

    {

        private string accountName;

        private byte[] accountKey;



        public StorageCredentialsAccountAndKey(string accountName, string accountKey)

        {

            if (string.IsNullOrEmpty(accountName))

            {

                throw new ArgumentException("The account name cannot be empty", "accountName");

            }



            if (string.IsNullOrEmpty(accountKey))

            {

                throw new ArgumentException("The account key cannot be empty", "accountKey");

            }



            this.accountName = accountName;

            this.accountKey = Convert.FromBase64String(accountKey.ToString());

        }



        public void SignRequest(WebRequest webRequest, long contentLength)

        {

            if (webRequest != null)

            {

                webRequest.Headers["x-ms-date"] = this.GetDateHeader();

                webRequest.Headers["Authorization"] = GetAuthenticationHeader(webRequest, contentLength, this.accountName, this.accountKey);

            }

        }



        public void SignRequestLite(WebRequest webRequest)

        {

            if (webRequest != null)

            {

                this.AddAuthenticationHeadersLite(new RequestData { Method = webRequest.Method, RequestUri = webRequest.RequestUri }, webRequest.Headers);

            }

        }



        public void AddAuthenticationHeadersLite(RequestData requestData, WebHeaderCollection requestHeaders)

        {

            if (requestHeaders != null)

            {

                var xmsdate = this.GetDateHeader();

                requestHeaders["x-ms-version"] = "2009-09-19";

                requestHeaders["x-ms-date"] = xmsdate;

                requestHeaders["Authorization"] = GetAuthenticationHeaderLite(requestData, this.accountName, this.accountKey, xmsdate);

            }

        }



        internal virtual string GetDateHeader()

        {

            return DateTime.UtcNow.ToString("R", CultureInfo.InvariantCulture);

        }



        private static string GetCanonicalizedResourceVersion2(Uri address, string accountName)

        {

            var builder = new StringBuilder("/");

            builder.Append(accountName);

            builder.Append(address.AbsolutePath);



            var canonicalizedString = new CanonicalizedString(builder.ToString());

            var values = HttpUtility.ParseQueryString(address.Query);

            var allValues = new WebHeaderCollection();

            foreach (string key in values.AllKeys)

            {

                var list = new List<string>(values.GetValues(key));

                list.Sort();



                var innerBuilder = new StringBuilder();

                foreach (object obj2 in list)

                {

                    if (innerBuilder.Length > 0)

                    {

                        innerBuilder.Append(",");

                    }



                    innerBuilder.Append(obj2.ToString());

                }



                allValues.Add(string.IsNullOrEmpty(key) ? key : key.ToLowerInvariant(), innerBuilder.ToString());

            }



            var keyList = new List<string>(allValues.AllKeys);

            keyList.Sort();



            foreach (string key in keyList)

            {

                var innerBuilder = new StringBuilder(string.Empty);

                innerBuilder.Append(key);

                innerBuilder.Append(":");

                innerBuilder.Append(allValues[key]);

                canonicalizedString.AppendCanonicalizedElement(innerBuilder.ToString());

            }



            return canonicalizedString.Value;

        }



        private static string GetStandardHeaderValue(WebHeaderCollection headers, string headerName)

        {

            var headerValues = GetHeaderValues(headers, headerName);

            if (headerValues.Count != 1)

            {

                return string.Empty;

            }



            return (string)headerValues[0];

        }



        private static List<string> GetHeaderValues(WebHeaderCollection headers, string headerName)

        {

            var list = new List<string>();

            var values = headers.GetValues(headerName);

            if (values != null)

            {

                foreach (string value in values)

                {

                    list.Add(value.TrimStart(new char[0]));

                }

            }



            return list;

        }



        private static string CanonicalizeHttpRequest(string accountName, long contentLength, WebRequest webRequest)

        {

            var canonicalizedString = new CanonicalizedString(webRequest.Method);

            canonicalizedString.AppendCanonicalizedElement(GetStandardHeaderValue(webRequest.Headers, "Content-Encoding"));

            canonicalizedString.AppendCanonicalizedElement(GetStandardHeaderValue(webRequest.Headers, "Content-Language"));

            canonicalizedString.AppendCanonicalizedElement((contentLength == -1L) ? string.Empty : contentLength.ToString(CultureInfo.InvariantCulture));

            canonicalizedString.AppendCanonicalizedElement(GetStandardHeaderValue(webRequest.Headers, "Content-MD5"));

            canonicalizedString.AppendCanonicalizedElement(webRequest.ContentType);

            canonicalizedString.AppendCanonicalizedElement(!string.IsNullOrEmpty(GetStandardHeaderValue(webRequest.Headers, "x-ms-date")) ? string.Empty : GetStandardHeaderValue(webRequest.Headers, "Date"));

            canonicalizedString.AppendCanonicalizedElement(GetStandardHeaderValue(webRequest.Headers, "If-Modified-Since"));

            canonicalizedString.AppendCanonicalizedElement(GetStandardHeaderValue(webRequest.Headers, "If-Match"));

            canonicalizedString.AppendCanonicalizedElement(GetStandardHeaderValue(webRequest.Headers, "If-None-Match"));

            canonicalizedString.AppendCanonicalizedElement(GetStandardHeaderValue(webRequest.Headers, "If-Unmodified-Since"));

            canonicalizedString.AppendCanonicalizedElement(GetStandardHeaderValue(webRequest.Headers, "Range"));

            AddCanonicalizedHeaders(webRequest.Headers, canonicalizedString);

            AddCanonicalizedResourceVersion2(webRequest.RequestUri, accountName, canonicalizedString);

            return canonicalizedString.Value;

        }



        private static void AddCanonicalizedResourceVersion2(Uri address, string accountName, CanonicalizedString canonicalizedString)

        {

            var element = GetCanonicalizedResourceVersion2(address, accountName);



            canonicalizedString.AppendCanonicalizedElement(element);

        }



        private static void AddCanonicalizedHeaders(WebHeaderCollection headers, CanonicalizedString canonicalizedString)

        {

            var keyList = new List<string>();

            foreach (string key in headers.AllKeys)

            {

                if (key.ToLowerInvariant().StartsWith("x-ms-", StringComparison.Ordinal))

                {

                    keyList.Add(key.ToLowerInvariant());

                }

            }



            keyList.Sort();

            foreach (string key in keyList)

            {

                var builder = new StringBuilder(key);

                var colonAndComma = ":";

                foreach (string values in GetHeaderValues(headers, key))

                {

                    string value = values.Replace("\r\n", string.Empty);

                    builder.Append(colonAndComma);

                    builder.Append(value);

                    colonAndComma = ",";

                }



                canonicalizedString.AppendCanonicalizedElement(builder.ToString());

            }

        }



        private static string ComputeMacSha256(byte[] accountKey, string canonicalizedString)

        {

            var bytes = Encoding.UTF8.GetBytes(canonicalizedString);

            using (var hmacsha = new HMACSHA256(accountKey))

            {

                return Convert.ToBase64String(hmacsha.ComputeHash(bytes));

            }

        }



        private static string CanonicalizeHttpRequestLite(string accountName, string xmsdate, Uri requestUri)

        {

            if (string.IsNullOrEmpty(xmsdate))

            {

                throw new ArgumentException(

                        string.Format(

                        CultureInfo.CurrentCulture,

                        "Canonicalization did not find a non empty x-ms-date header in the WebRequest. Please use a WebRequest with a valid x-ms-date header in RFC 123 format (example request.Headers[\"x-ms-date\"] = DateTime.UtcNow.ToString(\"R\", CultureInfo.InvariantCulture))",

                        new object[0]),

                    "xmsdate");

            }



            var canonicalizedString = new CanonicalizedString(xmsdate);

            canonicalizedString.AppendCanonicalizedElement(GetCanonicalizedResourceLite(requestUri, accountName));



            return canonicalizedString.Value;

        }



        private static string GetCanonicalizedResourceLite(Uri address, string accountName)

        {

            var builder = new StringBuilder("/");

            builder.Append(accountName);

            builder.Append(address.AbsolutePath);



            var parsedQuery = HttpUtility.ParseQueryString(address.Query);

            var compQuery = parsedQuery["comp"] != null ? parsedQuery["comp"] : string.Empty;

            if (!string.IsNullOrEmpty(compQuery))

            {

                builder.Append("?comp=");

                builder.Append(compQuery);

            }



            return builder.ToString();

        }



        private static string GetAuthenticationHeader(WebRequest webRequest, long contentLength, string accountName, byte[] accountKey)

        {

            var canonicalizedString = CanonicalizeHttpRequest(accountName, contentLength, webRequest);

            var hmacsha256 = ComputeMacSha256(accountKey, canonicalizedString);



            return string.Format(CultureInfo.InvariantCulture, "SharedKey {0}:{1}", accountName, hmacsha256);

        }



        private static string GetAuthenticationHeaderLite(RequestData requestData, string accountName, byte[] accountKey, string xmsdate)

        {

            var canonicalizedString = CanonicalizeHttpRequestLite(accountName, xmsdate, requestData.RequestUri);

            var hmacsha256 = ComputeMacSha256(accountKey, canonicalizedString);



            return string.Format(CultureInfo.InvariantCulture, "SharedKeyLite {0}:{1}", accountName, hmacsha256);

        }

    }

}