Problems Authenticating to Storage Emulator with Signed REST

Question

Hi there,

I have method that simply makes a REST call to table storage and returns the raw ATOM feed to me.  It works great with the live table storage, but for some reason or another I do not seem to be able to get it to authenticate to the storage emulator.

I'm using the following code to create the signature...

HttpWebRequest request = (HttpWebRequest)HttpWebRequest.Create(uri);

request.Method = "GET";
request.ContentLength = 0;
request.Headers.Add("x-ms-date", DateTime.UtcNow.ToString("R", System.Globalization.CultureInfo.InvariantCulture));

// Now sign the request
string signature = "GET\n";

// Content-MD5
signature += "\n";

// Content-Type
signature += "\n";

// Date
signature += request.Headers["x-ms-date"] + "\n";

// Canonicalized Resource
// remove the query string
int q = pStrTableName.IndexOf("?");
if (q > 0) pStrTableName = TableName.Substring(0, q);

// Format is /{0}/{1} where 0 is name of the account and 1 is resources URI path
signature += "/" + cCSAAccount.Credentials.AccountName + "/" + pStrTableName;

// Hash-based Message Authentication Code (HMAC) using SHA256 hash
System.Security.Cryptography.HMACSHA256 hasher = null;
String key = "Eby8vdM02xNOcqFlqUwJPLlmEtlCDXJ1OUzFT50uSRZ6IFsuFq2UVErCz4I6tq/K1SZFPTOtr/KBHBeksoGMGw==";
hasher = new System.Security.Cryptography.HMACSHA256(Convert.FromBase64String(key));
 
// Authorization header
string authH = "SharedKey " + cCSAAccount.Credentials.AccountName + ":" + System.Convert.ToBase64String(hasher.ComputeHash(System.Text.Encoding.UTF8.GetBytes(signature)));

// Add the Authorization header to the request
request.Headers.Add("Authorization", authH);

 

Just to clarify that this is working great with live table storage, just not the emulator.

Thanks in advance.

Answer 1

I think the issue is in the following line of code:

// Format is /{0}/{1} where 0 is name of the account and 1 is resources URI path
signature += "/" + cCSAAccount.Credentials.AccountName + "/" + pStrTableName;

Please refer to the "Constructing the Canonicalized Resource String" section (read Note there) from here: http://msdn.microsoft.com/en-us/library/dd179428.aspx. Essentially your storage account name should appear twice in the code above when connecting to development storage.

Hope this helps.

Thanks

Gaurav Mantri

Cerebrata Software

http://www.cerebrata.com

 

 

 

 

Answer 2

Excellent thanks! That solved the problem :)