After enabling versioning in azure storage account. How can be download the versions of a blob using versionID in .net?

Question

After enabling versioning in azure storage account. How can be download the versions of a blob using versionID in .net?

Answer 1

@Rajat Saxena (NON EA SC ALT)

We have an example of list blob versions in .NET which you can modify to download the blob versions. Here is a sample that uses the DownloadTo method:

private static void DownloadBlobVersions(BlobContainerClient blobContainerClient, string blobName)
{
    try
    {
        // Call the listing operation, specifying that blob versions are returned.
        // Use the blob name as the prefix.
        var blobVersions = blobContainerClient.GetBlobs
            (BlobTraits.None, BlobStates.Version, prefix: blobName)
            .OrderByDescending(version => version.VersionId)
            .Where(blob => blob.Name == blobName);

        // Construct the URI for each blob version and download it to a local file.
        foreach (var version in blobVersions)
        {
            BlobUriBuilder blobUriBuilder = new BlobUriBuilder(blobContainerClient.Uri)
            {
                BlobName = version.Name,
                VersionId = version.VersionId
            };

            // Get a reference to the blob version using the URI.
            BlobClient blobClient = new BlobClient(blobUriBuilder.ToUri());

            // Download the blob version to a local file with the version ID as the suffix.
            string filePath = @"C:\Users\user\Downloads\" + blobName + "_" + version.VersionId;
            blobClient.DownloadTo(filePath);

            if ((bool)version.IsLatestVersion.GetValueOrDefault())
            {
                Console.WriteLine("Current version downloaded: {0}", filePath);
            }
            else
            {
                Console.WriteLine("Previous version downloaded: {0}", filePath);
            }
        }
    }
    catch (RequestFailedException e)
    {
        Console.WriteLine(e.Message);
        Console.ReadLine();
        throw;
    }
}

Hope this helps! Let me know if you have further questions.

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Answer 2

@Sumarigo-MSFT I would like to clarify the behavior of blob versioning in a scenario where it was initially disabled, then you updated the blob data, and finally, you enabled versioning for the first time. In this situation, the current version appears to be blank. Is this behavior expected?