访问 azure 表实体

Question

大家好，我想使用 REST API 或使用 Odata 从 Windows Phone 访问 azure 表实体。 我写了一个代码，但这给了我 NULL 响应。每次我想访问一个表实体时，我都会调用 GetEntity 函数。下面是我正在使用的代码。 请如果有人知道此代码有什么问题或任何帮助尽快回复。

///////////获取实体函数。/////////

     private void GetEntity(String tableName, String partitionKey, String rowKey)
    {
        String requestMethod = "GET";

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


        String dateInRfc1123Format = DateTime.Now.ToString("R", System.Globalization.CultureInfo.InvariantCulture);

        String canonicalizedResource = String.Format("/{0}/{1}", AzureStorageConstants.Account, urlPath);
        String stringToSign = String.Format(
              "{0}\n\n\n{1}\n{2}",
              requestMethod,
              dateInRfc1123Format,
              canonicalizedResource);
        String authorizationHeader = CreateAuthorizationHeader(stringToSign);
        HttpWebResponse response;
        Uri uri = new Uri(AzureStorageConstants.TableEndPoint + urlPath);


        HttpWebRequest request = (HttpWebRequest)HttpWebRequest.Create(uri);
        request = (HttpWebRequest)WebRequest.Create(uri);
        request.Method = requestMethod;
        request.Headers[HttpRequestHeader.ProxyAuthorization] = null;
        request.Headers["Address"] = uri.ToString();
        request.Headers["Method"] = requestMethod;
        request.Headers["x-ms-date"]= DateTime.Now.ToString("R", System.Globalization.CultureInfo.InvariantCulture);
        request.Headers["x-ms-version"]= "2011-08-18";            
        request.Headers["Authorization"] = authorizationHeader;
        request.Headers["Accept-Charset"] = "UTF-8";
        request.Headers["ContentType"] = "application/atom+xml,application/xml";
        request.ContentType = "application/atom+xml,application/xml";
        request.Headers["DataServiceVersion"] = "1.0;NetFx";
        request.Headers["MaxDataServiceVersion"] = "1.0;NetFx";

       using (response = GetResponse(request))
        {
            Stream dataStream = response.GetResponseStream();
            using (StreamReader reader = new StreamReader(dataStream))
            {
                String responseFromServer = reader.ReadToEnd();
            }
        }
    }

// 获取响应函数。

       public HttpWebResponse GetResponse(HttpWebRequest request)
       {
        var dataReady = new AutoResetEvent(false);
        HttpWebResponse response = null;
        var callback = new AsyncCallback(delegate(IAsyncResult asynchronousResult)
        {
            response = (HttpWebResponse)request.EndGetResponse(asynchronousResult);
            dataReady.Set();
        });

        request.BeginGetResponse(callback, request);
            return response;
    }

////// 创建授权函数。///

      private String CreateAuthorizationHeader(String canonicalizedString)
    {
   String signature = string.Empty;
 using (HMACSHA256 hmacSha256 = new HMACSHA256(Convert.FromBase64String(AzureStorageConstants.Key))) 

 {
     Byte[] dataToHmac = System.Text.Encoding.UTF8.GetBytes(canonicalizedString);
     signature = Convert.ToBase64String(hmacSha256.ComputeHash(dataToHmac));
 }

String authorizationHeader = String.Format(
       CultureInfo.InvariantCulture,
       "{0} {1}:{2}",
       AzureStorageConstants.SharedKeyAuthorizationScheme,
       AzureStorageConstants.Account,
       signature);

return authorizationHeader;

}

////////AzureStorageConstants.

      public static class AzureStorageConstants
    {


     private static String TableAccount = "datablobs";
     private static String cloudEndPointFormat = "http://" + TableAccount + ".table.core.windows.net/";


    private static String cloudKey = "Primary Access Key";// Here actual key is written.
    private static string AzureStorage_SharedKeyAuthorizationScheme = "SharedKey";


        public static String Account
        {
            get { return TableAccount; }
        }

        public static string SharedKeyAuthorizationScheme
        {
            get { return AzureStorage_SharedKeyAuthorizationScheme; }
        }

        public static string Key
        {
            get { return  cloudKey; }
        }

        public static String TableEndPoint
        {
            get { return cloudEndPointFormat; }
        }
    }

Answer 1

有关解决方案，请参阅下面的链接，我已将解决方案发布在 http://social.msdn.microsoft.com/Forums/en-US/windowsazureconnectivity/thread/84415c36-9475-4af0-9f52-c534f5681432

Answer 2

我检查了您的代码，发现 GetEntity() 函数在创建签名以访问 Windows Azure 表存储方面确实存在一些问题，因此我将以下代码组合在一起，它确实有效。您只需替换您的 GetEntity() 并添加以下代码中包含的另外两个函数即可正常工作签名过程。

private string GetEntity(String tableName, String partitionKey, String rowKey)
{
    string result = "";
    String requestMethod = "GET";
    String urlPath = String.Format("{0}(PartitionKey='{1}',RowKey='{2}')",tableName, partitionKey, rowKey);
    DateTime now = DateTime.UtcNow;
    HttpWebResponse response;
    string uri = AzureStorageConstants.TableEndPoint + urlPath;
    HttpWebRequest request = (HttpWebRequest)HttpWebRequest.Create(uri);
    request.Method = requestMethod;
    request.ContentLength = 0;
    request.Headers.Add("x-ms-date", now.ToString("R", System.Globalization.CultureInfo.InvariantCulture));
    request.Headers.Add("x-ms-version", "2009-09-19");
    request.ContentType = "application/atom+xml";
    request.Headers.Add("DataServiceVersion", "1.0;NetFx");
    request.Headers.Add("MaxDataServiceVersion", "1.0;NetFx");
    request.Headers.Add("If-Match", "*");
    request.Headers.Add("Accept-Charset", "UTF-8");
    request.Headers.Add("Authorization", AuthorizationHeader(requestMethod, now, request));
    request.Accept = "application/atom+xml";
    using (response = request.GetResponse() as HttpWebResponse)
    {
        Stream dataStream = response.GetResponseStream();
        using (StreamReader reader = new StreamReader(dataStream))
        {
            result = reader.ReadToEnd();
        }
    }
    return result;
}

public string AuthorizationHeader(string method, DateTime now, HttpWebRequest request)
{
    string MessageSignature;
    MessageSignature = String.Format("{0}\n\n{1}\n{2}\n{3}",
        method,
        "application/atom+xml",
        now.ToString("R", System.Globalization.CultureInfo.InvariantCulture),
        GetCanonicalizedResource(request.RequestUri, AzureStorageConstants.Account)
        );
    byte[] SignatureBytes = System.Text.Encoding.UTF8.GetBytes(MessageSignature);
    System.Security.Cryptography.HMACSHA256 SHA256 = new System.Security.Cryptography.HMACSHA256(Convert.FromBase64String(AzureStorageConstants.Key));
    String AuthorizationHeader = "SharedKey " + AzureStorageConstants.Account + ":" + Convert.ToBase64String(SHA256.ComputeHash(SignatureBytes));
    return AuthorizationHeader;
}

public string GetCanonicalizedResource(Uri address, string accountName)
{
    StringBuilder str = new StringBuilder();
    StringBuilder builder = new StringBuilder("/");
    builder.Append(accountName);
    builder.Append(address.AbsolutePath);
    str.Append(builder.ToString());
    NameValueCollection values2 = new NameValueCollection();
    NameValueCollection values = HttpUtility.ParseQueryString(address.Query);
    foreach (string str2 in values.Keys)
    {
        ArrayList list = new ArrayList(values.GetValues(str2));
        list.Sort();
        StringBuilder builder2 = new StringBuilder();
        foreach (object obj2 in list)
        {
            if (builder2.Length > 0)
            {
                builder2.Append(",");
            }
            builder2.Append(obj2.ToString());
        }
        values2.Add((str2 == null) ? str2 : str2.ToLowerInvariant(), builder2.ToString());
    }
    ArrayList list2 = new ArrayList(values2.AllKeys);
    list2.Sort();
    foreach (string str3 in list2)
    {
        StringBuilder builder3 = new StringBuilder(string.Empty);
        builder3.Append(str3);
        builder3.Append(":");
        builder3.Append(values2[str3]);
        str.Append("\n");
        str.Append(builder3.ToString());
    }
    return str.ToString();
}

为了解决您与签名相关的问题，我从Storage_REST_CS sample 获取了代码，该代码具有通过 REST 接口访问 Windows Azure（Blob、表和队列）存储的出色实现。