Azure CloubdBlob的Properties.Length返回0 [英] Azure CloubdBlob's Properties.Length returns 0

问题描述

以下代码返回blob文件大小为0:

The following code returns blob file size of 0:

public long GetFileSize(string fileUrl)
{
    var blob = GetBlobContainer().GetBlobReference(fileUrl);
    return blob == null ? 0 : blob.Properties.Length;
}

，几乎找不到它.但是，我删除了Blob之后，我发现它已被删除.删除时有效:

, its almost as it does not find the blob. But of I delete the blob I see that it gets deleted. This works when deleting:

void DeleteFileFromBlob(string fileUrl, bool deleteSnapshots)
{
    var blob = GetBlobContainer().GetBlobReference(fileUrl);
    if (deleteSnapshots)
    {
        var options = new BlobRequestOptions { DeleteSnapshotsOption = DeleteSnapshotsOption.IncludeSnapshots };
        blob.DeleteIfExists(options);
    }
    else blob.DeleteIfExists();
}

它与上面的代码基本相同，因此似乎找到了blob.

Its basically the same code as the one above, so it seems that the blob is found.

如果我遍历blob，我将获得正确的blob文件大小，就像在计算存储的总字节数时所做的那样:

If I iterate through the blobs I get the correct blob file size, like I do when I calculate the total amount of stored bytes i my storage:

public long GetStorageUsageByteSize()
{
    var blobClient = GetBlobClient();
    return (from container in blobClient.ListContainers()
                      select
                      (from CloudBlob blob in
                           container.ListBlobs(new BlobRequestOptions { UseFlatBlobListing = true })
                       select blob.Properties.Length
                      ).Sum()
                     ).Sum();            
}

因此，我无法弄清楚当我将GetBlobReference与URL一起使用时，CloubdBlob :: Properties.Length为什么返回0的原因.

So, I cant figure out why the CloubdBlob::Properties.Length returns 0 when I use GetBlobReference with a url.

推荐答案

您似乎缺少对FetchAttributes方法的调用，该方法加载了Blob的元数据:

It looks like you're missing a call to the FetchAttributes method, which loads the blob's metadata:

blob.FetchAttributes(); 

参考: https://azure.microsoft.com/en-us/documentation/articles/storage-properties-metadata/

这篇关于Azure CloubdBlob的Properties.Length返回0的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！