b2sdk.transferer.parallel

class b2sdk.transferer.parallel.AbstractDownloaderThread(session, writer, part_to_download, chunk_size)

Bases: threading.Thread

__init__(session, writer, part_to_download, chunk_size)

Parameters

• session – raw_api wrapper

• writer – where to write data

• part_to_download – PartToDownload object

• chunk_size – internal buffer size to use for writing and hashing

abstract run()

Method representing the thread’s activity.

You may override this method in a subclass. The standard run() method invokes the callable object passed to the object’s constructor as the target argument, if any, with sequential and keyword arguments taken from the args and kwargs arguments, respectively.

class b2sdk.transferer.parallel.FirstPartDownloaderThread(response, hasher, *args, **kwargs)

Bases: b2sdk.transferer.parallel.AbstractDownloaderThread

__init__(response, hasher, *args, **kwargs)

Parameters

• response – response of the original GET call

• hasher – hasher object to feed to as the stream is written

run()

Method representing the thread’s activity.

You may override this method in a subclass. The standard run() method invokes the callable object passed to the object’s constructor as the target argument, if any, with sequential and keyword arguments taken from the args and kwargs arguments, respectively.

class b2sdk.transferer.parallel.NonHashingDownloaderThread(url, *args, **kwargs)

Bases: b2sdk.transferer.parallel.AbstractDownloaderThread

__init__(url, *args, **kwargs)

Parameters

url – url of the target file

run()

Method representing the thread’s activity.

You may override this method in a subclass. The standard run() method invokes the callable object passed to the object’s constructor as the target argument, if any, with sequential and keyword arguments taken from the args and kwargs arguments, respectively.

class b2sdk.transferer.parallel.ParallelDownloader(max_streams, min_part_size, *args, **kwargs)

Bases: b2sdk.transferer.abstract.AbstractDownloader

FINISH_HASHING_BUFFER_SIZE = 1048576

__init__(max_streams, min_part_size, *args, **kwargs)

Parameters

• max_streams – maximum number of simultaneous streams

• min_part_size – minimum amount of data a single stream will retrieve, in bytes

download(file, response, metadata, session)

Downloads a file from given url using parallel download sessions and stores it in the given download_destination.

Parameters

• file – an opened file-like object to write to

• response – The response of the first request made to the cloud service with download intent

Returns

is_suitable(metadata, progress_listener)

analyzes metadata (possibly against options passed earlier to constructor to find out whether the given download request should be handled by this downloader)

class b2sdk.transferer.parallel.PartToDownload(cloud_range, local_range)

Bases: object

Holds the range of a file to download, and the range of the local file where it should be stored.

__init__(cloud_range, local_range)

Initialize self. See help(type(self)) for accurate signature.

class b2sdk.transferer.parallel.WriterThread(file)

Bases: threading.Thread

__init__(file)

This constructor should always be called with keyword arguments. Arguments are:

group should be None; reserved for future extension when a ThreadGroup class is implemented.

target is the callable object to be invoked by the run() method. Defaults to None, meaning nothing is called.

name is the thread name. By default, a unique name is constructed of the form “Thread-N” where N is a small decimal number.

args is the argument tuple for the target invocation. Defaults to ().

kwargs is a dictionary of keyword arguments for the target invocation. Defaults to {}.

If a subclass overrides the constructor, it must make sure to invoke the base class constructor (Thread.__init__()) before doing anything else to the thread.

run()

Method representing the thread’s activity.

You may override this method in a subclass. The standard run() method invokes the callable object passed to the object’s constructor as the target argument, if any, with sequential and keyword arguments taken from the args and kwargs arguments, respectively.

b2sdk.transferer.parallel.gen_parts(cloud_range, local_range, part_count)

Generates a sequence of PartToDownload to download a large file as a collection of parts.