Is there a way to know if a blob file exists inside a container without getting the whole list of blob objects ?
Thanks,
3 Answers
If you know the address of the blob, a tip from the Azure SDK is to first build a CloudBlockBlob (or a CloudPageBlob) and then call FetchAttributes. This call will throw a StorageClientException if it cannot locate the blob.
From the CloudBlobClient.GetBlockBlobReference documentation:
The FetchAttributes method executes a HEAD request to populate the blob's properties and metadata and as such is a lightweight option for determining whether the blob exists.
Comments
Starting from Windows Azure Storage Client Library 2.0, the blob contains method Exists(), e.g: blob.Exists()
the same is true for the BlobContainer.
Comments
This is the code that I'm using
public static bool Exists(this CloudBlob blob)
{
try
{
blob.FetchAttributes();
return true;
}
catch (StorageClientException e)
{
if (e.ErrorCode == StorageErrorCode.ResourceNotFound)
{
return false;
}
else
{
throw;
}
}
}
3 Comments
user94559
That probably comes from here: blog.smarx.com/posts/testing-existence-of-a-windows-azure-blob. :-) Also, it's in my smarx.WasStorageExtensions NuGet package.
Andrew Harry
Has this changed with SDK 1.7?
d.popov
This is no longer relevant, since in SDK2.x (2.3) they have removed it. They made a complete shit out of the library!!! stackoverflow.com/questions/14363564/… is showing how to handle these exceptions, but the Error code is inside a prop, that is NULL most of the time, which will THROW an exception when you try to handle the code !!! The fall-back is to use the status codes! Great improvement, right? The new SDK is awesome!
