/// <summary>
/// Returns the information associated to a blob.
/// </summary>
/// <param name="blobPath"></param>
/// <returns></returns>
public async Task <BlobInfo> GetBlobInfoAsync(string blobPath)
{
BlobInfo result = null;
CloudBlobClient blobClient = m_LazyBlobClient.Value;
CloudBlob blob = new CloudBlob(GetAbsoluteBlobUri(blobPath), blobClient.Credentials);
//`ExistsAsync` also refreshes properties and metadata at the same times
if (await blob.ExistsAsync())
{
result = AzureBlob.FromBlobProperties(GetBlobPath(blob), blob.Properties, blob.Metadata);
}
return(result);
}
/// <summary>
/// Returns the list of blobs matching the specified path.
/// </summary>
/// <param name="blobPathPrefix"></param>
/// <returns></returns>
public async Task <List <BlobInfo> > ListBlobAsync(string blobPathPrefix)
{
//$root container is not implicitly supported, at least an explicit container name is expected
string prefix = blobPathPrefix ?? throw new ArgumentNullException(nameof(blobPathPrefix));
if (string.IsNullOrWhiteSpace(prefix))
{
throw new ArgumentException(nameof(blobPathPrefix));
}
CloudBlobClient blobClient = m_LazyBlobClient.Value;
BlobContinuationToken continuationToken = null;
//pad prefix path for container only with trailing slash '/', otherwise storage SDK list in $root container only
if (!prefix.Contains('/'))
{
prefix += '/';
}
var result = new List <BlobInfo>();
try
{
do
{
BlobResultSegment segment = await blobClient.ListBlobsSegmentedAsync(prefix, true, BlobListingDetails.Metadata, null, continuationToken, null, null);
continuationToken = segment.ContinuationToken;
result.AddRange(segment.Results.Cast <CloudBlob>().Select(b => AzureBlob.FromBlobProperties(GetBlobPath(b), b.Properties, b.Metadata)));
} while (continuationToken != null);
}
catch (StorageException ex) when(ex.RequestInformation.ErrorCode == BlobErrorCodeStrings.ContainerNotFound)
{
//swallow container not found and let the default return the currently empty list instead
}
return(result);
}
/// <summary>
/// Opens a stream for reading from the blob.
/// </summary>
/// <param name="blobPath">The relative path, from the storage root, to the blob.</param>
/// <exception cref="IdNotFoundException">The blob specified in <paramref name="blobPath"/> does not exist (<see cref="ErrorCodes.BlobNotFound"/>).</exception>
/// <returns></returns>
public async Task <BlobStreamDecorator> OpenBlobAsync(string blobPath)
{
CloudBlobClient blobClient = m_LazyBlobClient.Value;
CloudBlob blob = new CloudBlob(GetAbsoluteBlobUri(blobPath), blobClient.Credentials);
try
{
//blob properties and metadata are automatically fetched when opening the blob stream
Stream blobStream = await blob.OpenReadAsync();
BlobInfo blobInfo = AzureBlob.FromBlobProperties(GetBlobPath(blob), blob.Properties, blob.Metadata);
return(new BlobStreamDecorator(blobStream, blobInfo));
}
catch (StorageException ex) when(ex.RequestInformation.ErrorCode == BlobErrorCodeStrings.BlobNotFound || ex.RequestInformation.ErrorCode == BlobErrorCodeStrings.ContainerNotFound)
{
if (ex.RequestInformation.ErrorCode == BlobErrorCodeStrings.ContainerNotFound)
{
m_Logger.LogWarning($"Container '{blob.Container.Name}' does not exist");
}
throw new IdNotFoundException(ErrorCodes.BlobNotFound, blobPath);
}
}
