c# - Azure BLOB 存储 REST API 上传文件引发 403 - 禁止

Question

我正在尝试使用共享访问密钥(SAS) 将 PDF 上传到 Azure Blob 存储容器。代码运行良好，但突然开始抛出403 - Forbidden Exception。

响应状态消息：

服务器未能验证请求。确保 Authorization 标头的值正确形成，包括签名。

如此链接中所述，403 的可能原因之一可能是共享访问密钥已过期，因此我刷新了密钥并尝试使用新密钥，但仍然没有运气。

我正在调用UploadBlobToStorageContainer控制台应用程序（.NET Framework 4.6.2）的方法

代码：

    public string AzureStorageAccountName { get; set; }

    public string AzureStorageAccessKey { get; set; }

    public string X_MS_VERSION
    {
        get
        {
            return "2017-04-17";
        }
    }

    public string X_MS_CLIENT_REQUEST_ID
    {
        get
        {
            return _x_ms_client_request_id;
        }
    }

    public string BaseURI
    {
        get
        {
            return string.Format("https://{0}.blob.core.windows.net/", AzureStorageAccountName);
        }
    }

    private bool UploadBlobToStorageContainer(string filePath, string targetFolderPath, string containerName)
    {
        bool isUploaded = false;
        try
        {                
            FileInfo fileInfo = new FileInfo(filePath);
            long contentLength = fileInfo.Length;
            long range = contentLength - 1;
            string method = "PUT";
            string contentType = "application/pdf";
            string blobName = fileInfo.Name;
            string blobType = "BlockBlob";
            string dateString = DateTime.UtcNow.ToString("R", CultureInfo.InvariantCulture);
            string blobURI = BaseURI + containerName + "/" + blobName;
            string xmsHeader = $"x-ms-blob-type:{blobType}\nx-ms-date:{dateString}\nx-ms-version:{X_MS_VERSION}";
            string resHeader = $"/{AzureStorageAccountName}/{containerName}/{blobName}";

            if (!string.IsNullOrWhiteSpace(targetFolderPath))
            {
                blobName = targetFolderPath + "/" + fileInfo.Name;
            }
            
            if (WebRequest.Create(blobURI) is HttpWebRequest request)
            {
                request.Method = method;
                request.ContentLength = contentLength;
                request.Headers.Add("x-ms-blob-type", blobType);
                request.Headers.Add("x-ms-date", dateString);
                request.Headers.Add("x-ms-version", X_MS_VERSION);                    
                request.Headers.Add("Authorization", GetAuthorizationHeader(method, xmsHeader, resHeader, contentType, contentLength));

                using (Stream requestStream = request.GetRequestStream())
                {
                    byte[] fileContents = null;
                    using (FileStream fs = fileInfo.OpenRead())
                    {
                        fileContents = new byte[fs.Length];
                        fs.Read(fileContents, 0, fileContents.Length);
                        fs.Close();
                    }
                    requestStream.Write(fileContents, 0, fileContents.Length);
                }

                if (request.GetResponse() is HttpWebResponse response)
                {
                    if (response.StatusCode == HttpStatusCode.Created)
                    {
                        isUploaded = true;
                    }
                    else
                    {
                        isUploaded = false;
                    }
                }
            }
        }
        catch (Exception ex)
        {
            if (ex is WebException wex)
            {
                StringBuilder sb = new StringBuilder();
                if (wex.Response is HttpWebResponse exr)
                {
                    sb.Append("StatusCode: " + exr.StatusCode + " - ");
                    sb.Append("Description: " + exr.StatusDescription + " - ");
                }
                sb.Append("ErrorStatus: " + wex.Status);
                Log.LogMessage(LogLevel.ERROR, "AzureBlobApi: UploadBlobToContainer: File upload failed. Reason: " + sb.ToString());
            }
            Log.LogException(ex);
        }
        return isUploaded;
    }

    private string GetAuthorizationHeader(string method, string xmsHeader, string resHeader, string contentType, long contentLength)
    {
        //Do NOT REMOVE THE \n. It is a request header placeholder
        /*
            GET\n //HTTP Verb
            \n    //Content-Encoding
            \n    //Content-Language
            \n    //Content-Length (empty string when zero)
            \n    //Content-MD5
            \n    //Content-Type
            \n    //Date
            \n    //If-Modified-Since 
            \n    //If-Match
            \n    //If-None-Match
            \n    //If-Unmodified-Since
            \n    //Range
            x-ms-date:Fri, 26 Jun 2015 23:39:12 GMT
            x-ms-version:2015-02-21 //CanonicalizedHeaders
            /myaccount/mycontainer\ncomp:metadata\nrestype:container\ntimeout: 20    //CanonicalizedResource
        */
        
        string strToSign = $"{method}\n\n\n\n{contentLength}\n\n\n\n\n\n\n\n{xmsHeader}\n{resHeader}";

        string signatureString = GetHashedString(strToSign, AzureStorageAccessKey);

        string authorizationHeader = string.Format(
             CultureInfo.InvariantCulture,
             "{0} {1}:{2}",
             "SharedKey",
             AzureStorageAccountName,
             signatureString);

        return authorizationHeader;
    }

    private string GetHashedString(string signingString, string accessKey)
    {
        string encString = "";
        try
        {
            byte[] unicodeKey = Convert.FromBase64String(accessKey);
            using (HMACSHA256 hmacSha256 = new HMACSHA256(unicodeKey))
            {
                byte[] dataToHmac = Encoding.UTF8.GetBytes(signingString);
                encString = Convert.ToBase64String(hmacSha256.ComputeHash(dataToHmac));
            }
        }
        catch (Exception ex)
        {
            Log.LogMessage(LogLevel.ERROR, $"AzureBlobApi: GetHashedString: Exception getting hash string {ex.Message}");
        }
        return encString;
    }

标头

PUT



518262







x-ms-blob-type:BlockBlob
x-ms-date:Sun, 30 Aug 2020 08:43:31 GMT
x-ms-version:2017-04-17
/mystorage/documentcontainer/cricket/test document.pdf

任何帮助将非常感激。

谢谢 Raghunathan S

标签： c#http-status-code-403azure-blob-storageazure-rest-api

Answer 1

Http 403一般是认证失败引起的，请确保SAS有足够的权限在指定的容器中创建和写入blob，并确保容器本身已经存在（因为创建容器需要额外的权限），了解更多详情SAS 权限请参考创建服务 SAS和创建账户 SAS。

验证 SAS 是否具有足够权限的一种简单方法是blockBlob.UploadFromFile()在您的代码中调用 Azure 存储客户端库，并查看它是否有效或那里是否也报告了相同的错误。

要在 DMLib 中使用容器 SAS：

CloudBlockBlob blob = new CloudBlockBlob(new Uri("https://<storage>.blob.core.windows.net/<container_name/testaaa?st=2020-02-15T08%3A30%3A00Z&se=2020-02-20T08%3A30%3A00Z&sp=rwdl&sv=2016-05-31&sr=c&sig=<Replaced>"));
TransferManager.UploadAsync(@"c:\Test.pdf", blob).Wait();