I am writing automatic tests and I need to check if the Upload succeeded.
How do I do that? How come there is no FileExist method?
Exists method for blobs have been added in the new Storage Client Library 2.0 release. Since you are using an older library version, you can instead use FetchAttributes. It will throw an exception if the blob does not exist.
On the other hand, as Magnus also mentioned, Upload* methods throw an exception if they do not succeed.
I recommend checking file size for case that forexample connection to server was closed before completing data transfer.
public bool WriteDocumentStream(String documentId, Stream dataStream, long length)
{
CloudBlobContainer container = BlobClient.GetContainerReference(ContainerName);
CloudBlob blob = container.GetBlobReference(documentId);
blob.UploadFromStream(dataStream);
blob.FetchAttributes();
bool success = blob.Properties.Length == length;
if (!success)
blob.Delete();
return success;
}
//length should be like this: context.Request.ContentLength
//(if request have ContentLength defined at headers)
Related
I want to download a storage blob from Azure and stream it to a client via an .NET Web-App. The blob was uploaded correctly and is visible in my Azure storage account.
Surprisingly, the following throws an exception within HttpBaseStream:
[...]
var blobClient = _containerClient.GetBlobClient(Path.Combine(fileName));
var stream = await blobClient.OpenReadAsync();
return stream;
-> When i step further and return a File (return File(stream, MediaTypeNames.Application.Octet);), the download works as intended.
I tried to push the stream into an MemoryStream, which also fails with the same exception:
[...]
var blobClient = _containerClient.GetBlobClient(Path.Combine(fileName));
var stream = new MemoryStream();
await blobClient.DownloadToAsync(stream);
return stream
->When i step further, returning the file results in a timeout.
How can i fix that? Why do i get this exception - i followed the official quickstart guide from Microsoft.
the following throws an exception within HttpBaseStream
It looks like the HTTP result type is attempting to set the Content-Length header and is reading Length to do so. That would be the natural thing to do. However, it would also be natural to handle the NotSupportedException and just not set Content-Length at all.
If the NotSupportedException only shows up when running in the debugger, then just ignore it.
If the exception is actually thrown to your code (i.e., causing the request to fail), then you'll need to follow the rest of this answer.
First, create a minimal reproducible example and report a bug to the .NET team.
To work around this issue in the meantime, I recommend writing a stream wrapper that returns an already-determined length, which you can get from the Azure blob attributes. E.g.:
public sealed class KnownLengthStreamWrapper : Stream
{
private readonly Stream _stream;
public KnownLengthStreamWrapper(Stream stream, long length)
{
_stream = stream;
Length = length;
}
public override long Length { get; private set; }
... // override all other Stream members and forward to _stream.
}
That should be sufficient to get your app working.
I tried to push the stream into an MemoryStream
This didn't work because you'd need to "rewind" the MemoryStream at some point, e.g.:
var stream = new MemoryStream();
await blobClient.DownloadToAsync(stream);
stream.Position = 0;
return stream;
Check this sample of all the blob options which i have already posted on git working as expected. Reference
public void DownloadBlob(string path)
{
storageAccount = CloudStorageAccount.Parse(CloudConfigurationManager.GetSetting("StorageConnectionString"));
CloudBlobClient client = storageAccount.CreateCloudBlobClient();
CloudBlobContainer container = client.GetContainerReference("images");
CloudBlockBlob blockBlob = container.GetBlockBlobReference(Path.GetFileName(path));
using (MemoryStream ms = new MemoryStream())
{
blockBlob.DownloadToStream(ms);
HttpContext.Current.Response.ContentType = blockBlob.Properties.ContentType.ToString();
HttpContext.Current.Response.AddHeader("Content-Disposition", "Attachment; filename=" + Path.GetFileName(path).ToString());
HttpContext.Current.Response.AddHeader("Content-Length", blockBlob.Properties.Length.ToString());
HttpContext.Current.Response.BinaryWrite(ms.ToArray());
HttpContext.Current.Response.Flush();
HttpContext.Current.Response.Close();
}
}
I want to update json file in Blob Storage on Azure, while WebClient.uploadData(url,data) it gives the error:
The remote server returned an error: (405) The resource doesn't support specified Http Verb..
The code something like this:
[Route("PostJsonData")]
[HttpPost]
public void PostJSONData(string value)
{
try
{
string url = #"https://apkupdates.blob.core.windows.net/polaadapk/keywords.json";
byte[] json1 = new WebClient().DownloadData(url);
string result = System.Text.Encoding.UTF8.GetString(json1);
byte[] array = System.Text.Encoding.ASCII.GetBytes(value);
WebClient myWebClient = new WebClient();
Stream postStream = myWebClient.OpenWrite(url, "POST");
postStream.Write(array, 0, array.Length);
myWebClient.UploadData(url, array);
postStream.Close();
}
catch (Exception ex)
{
throw ex;
}
}
As Gaurav already mentioned, you are using the wrong verb. However, I would highly recommend to use the existing SDK for .NET:
Azure Storage APIs for .NET
The SDK also implements a exponential retry policy to handly transient errors (503 - Service Unavailble) which you otherwise have to implement yourself.
The correct HTTP verb for uploading is a blob is PUT and not POST. Because you're using POST instead of a PUT you're getting this error.
Please change the following line of code:
Stream postStream = myWebClient.OpenWrite(url, "POST");
to
Stream postStream = myWebClient.OpenWrite(url, "PUT");
And you should not get this MethodNotAllowed (405) error. Please note that you may get 403 error because the request is not authenticated. I would recommend reading Storage Service REST API documentation before proceeding.
I am using Azure storage to store and retrieve images. I have this method to save an image (blob):
public void SaveBlob(string containerName, string blobName, byte[] blob)
{
// Retrieve reference to the blob
CloudBlockBlob blockBlob = GetContainer(containerName, true).GetBlockBlobReference(blobName);
using (var stream = new MemoryStream(blob, writable: false))
{
blockBlob.UploadFromStream(stream);
}
}
This is the GetContainer method:
public CloudBlobContainer GetContainer(string containerName, bool createIfNotExist)
{
if (string.IsNullOrEmpty(containerName))
return null;
// Retrieve a reference to a container. If container doesn't exist, optionally create it.
CloudBlobContainer container = this._blobClient.GetContainerReference(containerName);
if (container == null && !createIfNotExist)
return null;
// Create the container if it doesn't already exist. It will be private by default.
container.CreateIfNotExists(BlobContainerPublicAccessType.Off, null, null);
return container;
}
What's happening here is that when I attempt to save a blob, I get a reference to a container first. If the container doesn't exist, it is created, and then the blob is saved. Will I run into timing issues here if I have to create the container first and then save a blob to it immediately? My concern is that I might be attempting to save the blob to the container before Azure is finished creating it. Or maybe this isn't an issue?
Looking at your code, I don't think you will run into any timing issues because CreateIfNotExists method is a sync method and will only return when the container is created. Also with Azure Blob Storage (unlike Amazon S3), the method will either create the container immediately or throw an error if it fails to do so (or in other words Azure Storage is Strongly Consistent).
Also I think this piece of code is redundant:
if (container == null && !createIfNotExist)
return null;
As container will never be equal to null and thus this if condition will never be true.
After I use CloudBlob.BeginUploadFromStream() method to upload a file, I later get a StorageClientException with StorageErrorCode.ResourceNotFound when trying to retrieve the file for a download. If I upload the same file using CloudBlob.UploadFromStream() method, then the blob DOES exist and i can download it.
here's my download code:
var client = _storageAccount.CreateCloudBlobClient();
var container = client.GetContainerReference(BLOB_CONTAINER_DOCUMENTS_ADDRESS);
container.CreateIfNotExist();
string blobName = id.ToString();
var newBlob = container.GetBlobReference(blobName);
if (newBlob.Exists())
{
var stream = newBlob.OpenRead();
return stream;
}
else
{
throw new Exception("Blob does not exist!");
}
Exists is an extension method. I'm getting the StorageClientException with the error code ResourceNotFound when I use the BeginUploadFromStream() method
public static bool Exists(this CloudBlob blob)
{
try
{
blob.FetchAttributes();
return true;
}
catch (StorageClientException e)
{
if (e.ErrorCode == StorageErrorCode.ResourceNotFound)
{
return false;
}
else
{
throw;
}
}
}
And my call to upload
var blob = container.GetBlobReference(blobName);
This will NOT throw an exception when i later check if the blob exists
blob.UploadFromStream(fileStream);
This will
AsyncCallback uploadCompleted = new AsyncCallback(OnUploadCompleted);
blob.BeginUploadFromStream(fileStream, uploadCompleted, documentId);
EDIT
As suggested, i didn't have a call to EndUploadFromStream() method. Here is my updated call to upload:
blob.BeginUploadFromStream(fileStream, uploadCompleted, blob);
And my handler
private void OnUploadCompleted(IAsyncResult result)
{
var blob = (CloudBlob) result.AsyncState;
blob.EndUploadFromStream(result);
}
Running this, the EndUploadFromStream() method throws a WebException with the msg: "The request was aborted: The request was canceled." The InnerException is "Cannot close stream until all bytes are written."
Anyone have any idea what's going on here?
BeginUploadFromStream uploads the blob asynchronously, so your method proceeds while the blob uploads on a thread in the background. If the blob hasn't finished uploading -- or if Azure hasn't been told that the upload has completed -- you won't see the blob in storage. Only blobs uploaded through successfully completed transactions are visible.
Could you post the code for OnUploadCompleted?
It looks at first glance as if either the blob is still uploading -- or you've forgotten to call EndUploadFromStream() in your OnUploadCompleted method.
What it sounds like is happening is IIS is cancelling the thread that is being initiated to make the BeginUploadFromStream. Since the storage API is really just manipulating a bunch of REST calls under the hood you can think of these storage calls as web service calls and not like traditional IO.
Check out this topic on HttpKeepAlives, this might solve your problem but as the article pointed out it may impact performance of your site. So you may want to add logic to only enable the keep alive for the requests that are performing the upload.
http://www.jaxidian.org/update/2007/05/05/8/
I'm converting a website from a standard ASP.NET website over to use Azure. The website had previously taken an Excel file uploaded by an administrative user and saved it on the file system. As part of the migration, I'm saving this file to Azure Storage. It works fine when running against my local storage through the Azure SDK. (I'm using version 1.3 since I didn't want to upgrade during the development process.)
When I point the code to run against Azure Storage itself, though, the process usually fails. The error I get is:
System.IO.IOException occurred
Message=Unable to read data from the transport connection: The connection was closed.
Source=Microsoft.WindowsAzure.StorageClient
StackTrace:
at Microsoft.WindowsAzure.StorageClient.Tasks.Task`1.get_Result()
at Microsoft.WindowsAzure.StorageClient.Tasks.Task`1.ExecuteAndWait()
at Microsoft.WindowsAzure.StorageClient.CloudBlob.UploadFromStream(Stream source, BlobRequestOptions options)
at Framework.Common.AzureBlobInteraction.UploadToBlob(Stream stream, String BlobContainerName, String fileName, String contentType) in C:\Development\RateSolution2010\Framework.Common\AzureBlobInteraction.cs:line 95
InnerException:
The code is as follows:
public void UploadToBlob(Stream stream, string BlobContainerName, string fileName,
string contentType)
{
// Setup the connection to Windows Azure Storage
CloudStorageAccount storageAccount = CloudStorageAccount.Parse(GetConnStr());
DiagnosticMonitorConfiguration dmc = DiagnosticMonitor.GetDefaultInitialConfiguration();
dmc.Logs.ScheduledTransferPeriod = TimeSpan.FromMinutes(1);
dmc.Logs.ScheduledTransferLogLevelFilter = LogLevel.Verbose;
DiagnosticMonitor.Start(storageAccount, dmc);
CloudBlobClient BlobClient = null;
CloudBlobContainer BlobContainer = null;
BlobClient = storageAccount.CreateCloudBlobClient();
// For large file copies you need to set up a custom timeout period
// and using parallel settings appears to spread the copy across multiple threads
// if you have big bandwidth you can increase the thread number below
// because Azure accepts blobs broken into blocks in any order of arrival.
BlobClient.Timeout = new System.TimeSpan(1, 0, 0);
Role serviceRole = RoleEnvironment.Roles.Where(s => s.Value.Name == "OnlineRates.Web").First().Value;
BlobClient.ParallelOperationThreadCount = serviceRole.Instances.Count;
// Get and create the container
BlobContainer = BlobClient.GetContainerReference(BlobContainerName);
BlobContainer.CreateIfNotExist();
//delete prior version if one exists
BlobRequestOptions options = new BlobRequestOptions();
options.DeleteSnapshotsOption = DeleteSnapshotsOption.None;
CloudBlob blobToDelete = BlobContainer.GetBlobReference(fileName);
Trace.WriteLine("Blob " + fileName + " deleted to be replaced by newer version.");
blobToDelete.DeleteIfExists(options);
//set stream to starting position
stream.Position = 0;
long totalBytes = 0;
//Open the stream and read it back.
using (stream)
{
// Create the Blob and upload the file
CloudBlockBlob blob = BlobContainer.GetBlockBlobReference(fileName);
try
{
BlobClient.ResponseReceived += new EventHandler<ResponseReceivedEventArgs>((obj, responseReceivedEventArgs)
=>
{
if (responseReceivedEventArgs.RequestUri.ToString().Contains("comp=block&blockid"))
{
totalBytes += Int64.Parse(responseReceivedEventArgs.RequestHeaders["Content-Length"]);
}
});
blob.UploadFromStream(stream);
// Set the metadata into the blob
blob.Metadata["FileName"] = fileName;
blob.SetMetadata();
// Set the properties
blob.Properties.ContentType = contentType;
blob.SetProperties();
}
catch (Exception exc)
{
Logging.ExceptionLogger.LogEx(exc);
}
}
}
I've tried a number of different alterations to the code: deleting a blob before replacing it (although the problem exists on new blobs as well), setting container permissions, not setting permissions, etc.
Your code looks like it should work, but it has lots of extra functionality that is not strictly required. I would cut it down to an absolute minimum and go from there. It's really only a gut feeling, but I think it might be the using statement giving you grief. This enture function could be written (presuming the container already exists) as:
public void UploadToBlob(Stream stream, string BlobContainerName, string fileName,
string contentType)
{
// Setup the connection to Windows Azure Storage
CloudStorageAccount storageAccount = CloudStorageAccount.Parse(GetConnStr());
CloudBlobClient BlobClient = storageAccount.CreateCloudBlobClient();
CloudBlobContainer BlobContainer = BlobClient.GetContainerReference(BlobContainerName);
CloudBlockBlob blob = BlobContainer.GetBlockBlobReference(fileName);
stream.Position = 0;
blob.UploadFromStream(stream);
}
Notes on the stuff that I've removed:
You should set up diagnostics just once when you're app starts, not every time a method is called. Usually in the RoleEntryPoint.OnStart()
I'm not sure why you're trying to set ParallelOperationThreadCount higher if you have more instances. Those two things seem unrelated.
It's not good form to check for the existence of a container/table every time you save something to it. It's more usual to do that check once when your app starts or to have a process external to the website to make sure all the required containers/tables/queues exist. Of course if you're trying to dynamically create containers this is not true.
The problem turned out to be firewall settings on my laptop. It's my personal laptop originally set up at home and so the firewall rules weren't set up for a corporate environment resulting in slow performance on uploads and downloads.