Why is CloudBlockBlob.DownloadToStream always returning an empty stream?

azure, azure-blob-storage, c#, streaming

Solution

Ah, I figured it out...

The following lines:

long streamlen = stream.Length;
blockBlob.UploadFromStream(stream);

need to be changed to

long streamlen = stream.Length;  
stream.Position = 0;
blockBlob.UploadFromStream(stream);

Problem

I have the following code: ``` public static void UploadStreamToBlob(Stream stream, string containerName, string blobName) { CloudStorageAccount storageAccount = CloudStorageAccount.Parse(CloudConfigurationManager.GetSetting("StorageConnectionString")); CloudBlobClient blobClient = storageAccount.CreateCloudBlobClient(); CloudBlobContainer blobContainer = blobClient.GetContainerReference(containerName); blobContainer.CreateIfNotExists(); blobContainer.SetPermissions( new BlobContainerPermissions { PublicAccess = BlobContainerPublicAccessType.Blob }); CloudBlockBlob blockBlob = blobContainer.GetBlockBlobReference(blobName); long streamlen = stream.Length; <-- This shows 203 bytes blockBlob.UploadFromStream(stream); } ``` and ``` public static Stream DownloadStreamFromBlob(string containerName, string blobName) { CloudStorageAccount storageAccount = CloudStorageAccount.Parse(CloudConfigurationManager.GetSetting("StorageConnectionString")); CloudBlobClient blobClient = storageAccount.CreateCloudBlobClient(); CloudBlobContainer blobContainer = blobClient.GetContainerReference(containerName); Stream stream = new MemoryStream(); CloudBlockBlob blockBlob = blobContainer.GetBlockBlobReference(blobName); if (blockBlob.Exists()) { blockBlob.DownloadToStream(stream); long streamlen = stream.Length; <-- This shows 0 bytes stream.Position = 0; } return stream; } ``` I'm running this in the Azure emulator, which I have pointed to my Sql Server. From what I can tell, it appears that the UploadFromStream is sending the data correctly, however, if I try and run the DownloadStreamFromBlob, it returns a 0 length stream. The blockBlob.Exists is returning true, so I assume it's there. I just can't figure out why my stream is empty. Btw, I'm passing in test and test for containerName and blobName on both calls. Any ideas?

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