Azure rest api put blob

Question

I am trying to put a blob with Azure rest api. i made a "GET" request successfully but i had issues with "PUT" request. When i try to make "PUT" request i get a 404error (i have seen same post in stackoverflow but it didnt help me).i am not sure if the MessageSignature that i use is correct(i have tried MessageSignaturePut but didnt work). Any suggestions?

public void UploadBlobWithRestAPI(string uri,  DateTime now)
{
    string blobName = "test.txt";
    string method = "PUT";
    string sampleContent = "This is sample text.";
    int contentLength = Encoding.UTF8.GetByteCount(sampleContent);
    string queryString = (new Uri(uri)).Query;
    string blobContainerUri = uri.Substring(0, uri.Length - queryString.Length);
    string requestUri = string.Format(CultureInfo.InvariantCulture, "{0}/{1}{2}", blobContainerUri, blobName, queryString);
    HttpWebRequest request = (HttpWebRequest)WebRequest.Create(requestUri);
    string nnow = now.ToString("R", System.Globalization.CultureInfo.InvariantCulture);

    request.Method = method;
    request.Headers.Add("x-ms-version", "2015-02-21");
    request.Headers.Add("x-ms-date", nnow);
    request.ContentType = "text/plain; charset=UTF-8";
    request.Headers.Add("x-ms-blob-type", "BlockBlob");
    request.ContentLength = contentLength;

    using (Stream requestStream = request.GetRequestStream())
    {
        requestStream.Write(Encoding.UTF8.GetBytes(sampleContent), 0, contentLength);
    }

    request.Headers.Add("Authorization", AuthorizationHeader(method, now, request, "", ""));

    using (HttpWebResponse resp = (HttpWebResponse)request.GetResponse())
    {
        MessageBox.Show(resp.StatusCode.ToString());
    }
}


public string AuthorizationHeader(string method, DateTime now, HttpWebRequest request,
        string ifMatch = "", string md5 = "")
{
    string MessageSignature;
    string StorageKey = "xxx";
    string StorageAccount = "upgradedevstorage";

    MessageSignature = String.Format("{0}\n\n\n{1}\n{5}\n\n\n\n{2}\n\n\n\n{3}{4}",
        method,
        (method == "GET" || method == "HEAD") ? String.Empty : request.ContentLength.ToString(),
        ifMatch,
        GetCanonicalizedHeaders(request),
        GetCanonicalizedResource(request.RequestUri, StorageAccount),
        md5
        );

 ???   //string MessageSignaturePut= String.Format("{0}\n\n{1}\n\n{2}{3}",
    //    method,
    //    "text/plain; charset=UTF-8",
    //    GetCanonicalizedHeaders(request),
    //    GetCanonicalizedResource(request.RequestUri, StorageAccount)
    //    );

    byte[] SignatureBytes = System.Text.Encoding.UTF8.GetBytes(MessageSignature);

    System.Security.Cryptography.HMACSHA256 SHA256 =
        new System.Security.Cryptography.HMACSHA256(Convert.FromBase64String(StorageKey));

    string signature = Convert.ToBase64String(SHA256.ComputeHash(SignatureBytes));

    string AuthorizationHeader = "SharedKey " + StorageAccount
        + ":" + Convert.ToBase64String(SHA256.ComputeHash(SignatureBytes));

    return AuthorizationHeader;
}

Answer 1

Please consider the following code snippet. This should work for you.

void UploadBlobWithRestAPI() {

    string storageKey = "<your access key here>";
    string storageAccount = "<your storage account name here>";    
    string containerName = "<your container name here>";
    string blobName = "test.txt";

    string method = "PUT";
    string sampleContent = "This is sample text.";
    int contentLength = Encoding.UTF8.GetByteCount(sampleContent);

    string requestUri = $"https://{storageAccount}.blob.core.windows.net/{containerName}/{blobName}";

    HttpWebRequest request = (HttpWebRequest)WebRequest.Create(requestUri);

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

    request.Method = method;
    request.ContentType = "text/plain; charset=UTF-8";
    request.ContentLength = contentLength;

    request.Headers.Add("x-ms-version", "2015-12-11");
    request.Headers.Add("x-ms-date", now);
    request.Headers.Add("x-ms-blob-type", "BlockBlob");
    request.Headers.Add("Authorization", AuthorizationHeader(method, now, request, storageAccount, storageKey, containerName, blobName));

    using (Stream requestStream = request.GetRequestStream()) {
        requestStream.Write(Encoding.UTF8.GetBytes(sampleContent), 0, contentLength);
    }

    using (HttpWebResponse resp = (HttpWebResponse)request.GetResponse()) {
        MessageBox.Show(resp.StatusCode.ToString());
    }

}

public string AuthorizationHeader(string method, string now, HttpWebRequest request, string storageAccount, string storageKey, string containerName, string blobName) {

    string headerResource = $"x-ms-blob-type:BlockBlob\nx-ms-date:{now}\nx-ms-version:2015-12-11";
    string urlResource = $"/{storageAccount}/{containerName}/{blobName}";
    string stringToSign = $"{method}\n\n\n{request.ContentLength}\n\n{request.ContentType}\n\n\n\n\n\n\n{headerResource}\n{urlResource}";

    HMACSHA256 hmac = new HMACSHA256(Convert.FromBase64String(storageKey));
    string signature = Convert.ToBase64String(hmac.ComputeHash(Encoding.UTF8.GetBytes(stringToSign)));

    String AuthorizationHeader = String.Format("{0} {1}:{2}", "SharedKey", storageAccount, signature);
    return AuthorizationHeader;
}

And the traffic captured by Fiddler as follows: