How can we load a list of Azure blob files recursively

Question

Hello guys,

Azure blob files are stored in a plain list without any physical folder structure, but we can create virtual folders where each file's folder path is a part of it's name.

It brings out another problem, how to retrieve a list of ALL files in virtual sub-folder, using only that folder's name?

TIA

Answer 1

Actually, there's a simpler way to do that and it is available in the library itself. If you look at CloudBlobContainer.ListBlobs method, it accepts two parameters:

1. prefix: This is the name of your directory. If it is a nested directory, you will need to specify the full path e.g. myfolder/mysubfolder.

2. useFlatBlobListing: Setting this value to true will ensure that only blobs are returned (including inside any sub folders inside that directory) and not directories and blobs.

var account = new CloudStorageAccount(new StorageCredentials(accountName, accountKey), true);
    var blobClient = account.CreateCloudBlobClient();
    var container = blobClient.GetContainerReference("blob-container-name");
    var blobs = container.ListBlobs(prefix: "container-directory", useFlatBlobListing: true);

You will get a list of all blobs belonging in the "container-directory" in blobs variable.

Hope this helps!!

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Thanks!!

Comments

To get to the Name property of the blob when I looped through the blobs I had to do this:

foreach (CloudBlockBlob blob in blobs)
{
     Console.WriteLine(blob.Name + " - " + blob.Uri.ToString());
}

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That's ittt? Well, I'll try and let you know! Thanks.

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Trying to get the size/length of the azure storage blob, file, queues& tables.

I am able to get the size of the blob by the below code but am not able to do it for others like files, queues & tables.

for (CloudBlobContainer cloudBlobContainer : cloudBlobContainers) {

                               Iterable<ListBlobItem> blobItems = cloudBlobContainer.listBlobs();

                                   for (ListBlobItem blobItem : blobItems) {
                                        if (blobItem instanceof CloudBlob) {
                                            CloudBlob blob = (CloudBlob) blobItem;
                                            size += blob.getProperties().getLength();
                                            logger.info("Size : "+blob.getProperties().getLength());
                                        }

                                    }

---

Hi Vyas, you can use this to get the length of blob queue:

try
{
    // Retrieve storage account from connection-string.
    CloudStorageAccount storageAccount =
       CloudStorageAccount.parse(storageConnectionString);

    // Create the queue client.
    CloudQueueClient queueClient = storageAccount.createCloudQueueClient();

    // Retrieve a reference to a queue.
    CloudQueue queue = queueClient.getQueueReference("myqueue");

   // Download the approximate message count from the server.
    queue.downloadAttributes();

    // Retrieve the newly cached approximate message count.
    long cachedMessageCount = queue.getApproximateMessageCount();

    // Display the queue length.
    System.out.println(String.format("Queue length: %d", cachedMessageCount));
}
catch (Exception e)
{
    // Output the stack trace.
    e.printStackTrace();
}