How to list subdirectories in Azure blob storage

Question

MS has announced directory like blob storage, and I'm trying to use it like directories. Having save some blobs by names:

Common\Service1\Type1\Object1
Common\Service1\Type1\Object2
Common\Service1\Type2\Object1
Common\Service1\Type2\Object2
Common\Service1\Type3\Object1
Common\Service1\Type3\Object2
Common\Service1\Type3\Object3

I'd like to have possibility to enumerate subdirectories, e.g. I have blobclient referenced to Common container name, and I would like to get subcontainers list Type1, Type2, Type3. Is it possible to get list of subdirectories in some directory. Using ListBlobs returns full list of blobs within current container.

Answer 1

If you would like to list all "subdirectories" in "Common\Service1" directory you can use something like this:

    var directory = blobContainer.GetDirectoryReference(@"Common/Service1");
    var folders = directory.ListBlobs().Where(b => b as CloudBlobDirectory != null).ToList();
    foreach (var folder in folders)
    {
        Console.WriteLine(folder.Uri);
    }

Full code sample:

    var random = new Random();
    CloudStorageAccount storageAccount = CloudStorageAccount.DevelopmentStorageAccount;
    var cloudBlobClient = storageAccount.CreateCloudBlobClient();
    CloudBlobContainer blobContainer = cloudBlobClient.GetContainerReference("test-container");
    blobContainer.CreateIfNotExists();
    string[] objects = new[]
                           {
                               @"Common\Service1\Type1\Object1", @"Common\Service1\Type1\Object2", @"Common\Service1\Type2\Object1",
                               @"Common\Service1\Type2\Object2", @"Common\Service1\Type3\Object1", @"Common\Service1\Type3\Object2",
                               @"Common\Service1\Type3\Object3"
                           };
    foreach (var newObject in objects)
    {
        var newBlob = blobContainer.GetBlockBlobReference(newObject);
        var buffer = new byte[1024];
        random.NextBytes(buffer);
        newBlob.UploadFromByteArray(buffer,0,buffer.Length);
    }

    var directory = blobContainer.GetDirectoryReference(@"Common/Service1");
    var folders = directory.ListBlobs().Where(b => b as CloudBlobDirectory != null).ToList();
    foreach (var folder in folders)
    {
        Console.WriteLine(folder.Uri);
    }

This will output Uri for Type1,Type2 and Type3 directory.

Answer 2

Building on b2zw2a's answer:

• The @ is only needed when using \, not /.
• Don't chain ToList() after ListBlobs(). ListBlobs() provides lazy loading and will give you better perf.
• Use OfType<CloudBlobDirectory>() to filter out only the type you want

Giving you:

var directory = blobContainer.GetDirectoryReference("Common/Service1");
var folders = directory.ListBlobs().OfType<CloudBlobDirectory>();
foreach (var folder in folders)
{
    Console.WriteLine(folder.Uri);
}