# -------------------------------------------------------------------------
# Copyright (c) Microsoft Corporation. All rights reserved.
# Licensed under the MIT License. See License.txt in the project root for
# license information.
# --------------------------------------------------------------------------
from typing import Iterator, Optional
from ._deserialize import from_blob_properties
[docs]class StorageStreamDownloader(object):
"""A streaming object to download from Azure Storage.
:ivar str name:
The name of the file being downloaded.
:ivar ~azure.storage.filedatalake.FileProperties properties:
The properties of the file being downloaded. If only a range of the data is being
downloaded, this will be reflected in the properties.
:ivar int size:
The size of the total data in the stream. This will be the byte range if speficied,
otherwise the total size of the file.
"""
def __init__(self, downloader):
self._downloader = downloader
self.name = self._downloader.name
self.properties = from_blob_properties(self._downloader.properties) # pylint: disable=protected-access
self.size = self._downloader.size
def __len__(self):
return self.size
[docs] def chunks(self) -> Iterator[bytes]:
"""Iterate over chunks in the download stream.
:rtype: Iterator[bytes]
"""
return self._downloader.chunks()
[docs] def read(self, size: Optional[int] = -1) -> bytes:
"""
Read up to size bytes from the stream and return them. If size
is unspecified or is -1, all bytes will be read.
:param size:
The number of bytes to download from the stream. Leave unsepcified
or set to -1 to download all bytes.
:returns:
The requsted data as bytes. If the return value is empty, there is no more data to read.
:rtype: bytes
"""
return self._downloader.read(size)
[docs] def readall(self) -> bytes:
"""Download the contents of this file.
This operation is blocking until all data is downloaded.
:rtype: bytes
"""
return self._downloader.readall()
[docs] def readinto(self, stream) -> int:
"""Download the contents of this file to a stream.
:param stream:
The stream to download to. This can be an open file-handle,
or any writable stream. The stream must be seekable if the download
uses more than one parallel connection.
:returns: The number of bytes read.
:rtype: int
"""
return self._downloader.readinto(stream)