CODEWITHSUNDEEP
c#azureazure-storageazure-blob-storage
Frank M
Frank M

Reputation: 533

Can enumerate and see blob in storage account but cannot access it

I'm working out of my local VS (2013 for one project, 2015 for the other.) I'm new to blobs and security, I had to pick up someone else's project which had slow upload speeds because they were uploading from the client browser to blob storage, and then taking the blob, creating a media asset and encoding the asset as mp4. Well I'm trying to put the encoding and creation of the media asset into a background process.

When I run localhost, I can upload and save to blob storage without a problem. I can see the blob in the Azure Portal, and have even set the access type on the blob to container. But when I try to retrieve the blob from background storage, it looks like I am getting a handle to the blob, but when I try to make a call to blob.FetchAttributes() I get a 404. I am using the correct storage connection string. There is a SAS token added to the URL (good for 1 year) and I have tried with and without the token.

I wrote this quick console app shown below, and when the blobs in the container are enumerated I see the blob that I uploaded, and that it has the correct size. Yet the call to blob.Exists() fails everytime. The redacted URL I am using for the fileName var to get the blob reference is being copied directly from the Azure portal. I have the correct credentials in my connection string, so I am not sure what is going on here. Any explanation would be greatly appreciated.

private static void ListBlobs()
{
    CloudStorageAccount storageAccount = CloudStorageAccount.Parse( CloudConfigurationManager.GetSetting("StorageConnectionString"));
    CloudBlobClient blobClient = storageAccount.CreateCloudBlobClient();
    var container=  blobClient.GetContainerReference("streamingfiles");

    // Loop over items within the container and output the length and URI.
    foreach (IListBlobItem item in container.ListBlobs(null, false))
    {
        if (item.GetType() == typeof(CloudBlockBlob))
        {
            CloudBlockBlob blob = (CloudBlockBlob)item;
            Console.WriteLine("Block blob of length {0}: {1}", blob.Properties.Length, blob.Uri);
        }
    }

    var fileName = "https://redacted.blob.core.windows.net/streamingfiles/47a49fb7-6f44-4f56-9695-37a4ddcd0f4a_56.mp4";//tried also with sas token
    var sourceCloudBlob = container.GetBlockBlobReference(fileName);

    if (sourceCloudBlob.Exists())
        Console.WriteLine("Exists");
    else
        Console.WriteLine("Does Not Exist"); //alwayd doesn't exist
}

Upvotes: 0

Views: 565

Answers (2)

Frank M
Frank M

Reputation: 533

I'm an idiot. What's the point of passing the full path to the file when I already am in the container: var fileName = "47a49fb7-6f44-4f56-9695-37a4ddcd0f4a_56.mp4";

Dev-One made me stop and think about it, but I can't mark that as correct.

Upvotes: 0

Sajal
Sajal

Reputation: 4401

An alternative to container.GetBlockBlobReference(fileName).Exists(); Set the flatBlobListing flag to true, since the blob structure are of flat hierarchy. 

// Loop over items within the container and output the length and URI.
foreach (IListBlobItem item in container.ListBlobs(null, true))
{
    if (item.GetType() == typeof(CloudBlockBlob))
    {
        CloudBlockBlob blob = (CloudBlockBlob)item;

        if (blob != null)
        {
            blob.FetchAttributes();
            Console.WriteLine("Fetching Attributes");
            string blobFilePath = blob.Uri.AbsolutePath.ToString();

            if(String.compare(blobFilePath, filename, true) == 0) 
            {
                Console.WriteLine("Exists");
            }
            else
            {
                Console.WriteLine("Does Not Exist")
            }

            Console.WriteLine("Block blob of length {0}: {1}", blob.Properties.Length, blob.Uri);
        }
    }
}

Upvotes: 0

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