Question

I’m trying to get some information about Azure blob (last modified UTC date time). This information is stored CloudBlob.Properties.LastModifiedUtc property.

If I use method GetBlobReference() or GetBlockBlobReference(), the Properties of the blob are not initialized (LastModifiedUtc is DateTime.MinDate). If I use ListBlobs() the Properties are initialized correctly (LastModifiedUtc has correct value).

Am I doing something wrong when using GetBlobReference function? Is there some way how to get CloudBlob instance just for one specific blob? I know I can missue ListBlobs() and filter just the blob I’m interested in, or use ListBlobsWithPrefix() from class CloudBlobClient, but I would expect to get all the metadata when I ask for specific Blob Reference.

Code showing how I’m working with Azure blobs:

    string storageAccountName = "test";
    string storageAccountKey = @"testkey";
    string blobUrl = "https://test.blob.core.windows.net";
    string containerName = "testcontainer";
    string blobName = "testbontainer";

    var credentials = new StorageCredentialsAccountAndKey(storageAccountName, storageAccountKey);
    var cloudBlobClient = new CloudBlobClient(blobUrl, credentials);
    var containerReference = cloudBlobClient.GetContainerReference(string.Format("{0}/{1}", blobUrl, containerName));

    // OK - Result is of type CloudBlockBlob, cloudBlob_ListBlobs.Properties.LastModifiedUtc > DateTime.MinValue
    var cloudBlob_ListBlobs = containerReference.ListBlobs().Where(i => i is CloudBlob && ((CloudBlob)i).Name == blobName).FirstOrDefault() as CloudBlob;

    // WRONG - Result is of type CloudBlob, cloudBlob_GetBlobReference.Properties.LastModifiedUtc == DateTime.MinValue
    var cloudBlob_GetBlobReference = containerReference.GetBlobReference(string.Format("{0}/{1}/{2}", blobUrl, containerName, blobName));

    // WRONG - Result is of type CloudBlockBlob, cloudBlob_GetBlockBlobReference.Properties.LastModifiedUtc == DateTime.MinValue
    var cloudBlob_GetBlockBlobReference = containerReference.GetBlockBlobReference(string.Format("{0}/{1}/{2}", blobUrl, containerName, blobName));

Answer 1

I believe you have to make a seperate call to fetch the attributes/metadata. After you have the blob referrence, issue the following line to retrieve the attributes.

cloudBlob_GetBlobReference.FetchAttributes();