keras/keras_core/utils/file_utils.py
2023-04-30 15:11:54 -07:00

382 lines
13 KiB
Python

import hashlib
import os
import pathlib
import shutil
import tarfile
import urllib
import warnings
import zipfile
from urllib.request import urlretrieve
from keras_core.api_export import keras_core_export
from keras_core.utils import io_utils
from keras_core.utils.progbar import Progbar
def path_to_string(path):
"""Convert `PathLike` objects to their string representation.
If given a non-string typed path object, converts it to its string
representation.
If the object passed to `path` is not among the above, then it is
returned unchanged. This allows e.g. passthrough of file objects
through this function.
Args:
path: `PathLike` object that represents a path
Returns:
A string representation of the path argument, if Python support exists.
"""
if isinstance(path, os.PathLike):
return os.fspath(path)
return path
def resolve_path(path):
return os.path.realpath(os.path.abspath(path))
def is_path_in_dir(path, base_dir):
return resolve_path(os.path.join(base_dir, path)).startswith(base_dir)
def is_link_in_dir(info, base):
tip = resolve_path(os.path.join(base, os.path.dirname(info.name)))
return is_path_in_dir(info.linkname, base_dir=tip)
def filter_safe_paths(members):
base_dir = resolve_path(".")
for finfo in members:
valid_path = False
if is_path_in_dir(finfo.name, base_dir):
valid_path = True
yield finfo
elif finfo.issym() or finfo.islnk():
if is_link_in_dir(finfo, base_dir):
valid_path = True
yield finfo
if not valid_path:
warnings.warn(
"Skipping invalid path during archive extraction: "
f"'{finfo.name}'.",
stacklevel=2,
)
def extract_archive(file_path, path=".", archive_format="auto"):
"""Extracts an archive if it matches a support format.
Supports `.tar`, `.tar.gz`, `.tar.bz`, and `.zip` formats.
Args:
file_path: Path to the archive file.
path: Where to extract the archive file.
archive_format: Archive format to try for extracting the file.
Options are `"auto"`, `"tar"`, `"zip"`, and `None`.
`"tar"` includes `.tar`, `.tar.gz`, and `.tar.bz` files.
The default `"auto"` uses `["tar", "zip"]`.
`None` or an empty list will return no matches found.
Returns:
`True` if a match was found and an archive extraction was completed,
`False` otherwise.
"""
if archive_format is None:
return False
if archive_format == "auto":
archive_format = ["tar", "zip"]
if isinstance(archive_format, str):
archive_format = [archive_format]
file_path = path_to_string(file_path)
path = path_to_string(path)
for archive_type in archive_format:
if archive_type == "tar":
open_fn = tarfile.open
is_match_fn = tarfile.is_tarfile
if archive_type == "zip":
open_fn = zipfile.ZipFile
is_match_fn = zipfile.is_zipfile
if is_match_fn(file_path):
with open_fn(file_path) as archive:
try:
if zipfile.is_zipfile(file_path):
# Zip archive.
archive.extractall(path)
else:
# Tar archive, perhaps unsafe. Filter paths.
archive.extractall(
path, members=filter_safe_paths(archive)
)
except (tarfile.TarError, RuntimeError, KeyboardInterrupt):
if os.path.exists(path):
if os.path.isfile(path):
os.remove(path)
else:
shutil.rmtree(path)
raise
return True
return False
@keras_core_export("keras_core.utils.get_file")
def get_file(
fname=None,
origin=None,
untar=False,
md5_hash=None,
file_hash=None,
cache_subdir="datasets",
hash_algorithm="auto",
extract=False,
archive_format="auto",
cache_dir=None,
):
"""Downloads a file from a URL if it not already in the cache.
By default the file at the url `origin` is downloaded to the
cache_dir `~/.keras`, placed in the cache_subdir `datasets`,
and given the filename `fname`. The final location of a file
`example.txt` would therefore be `~/.keras/datasets/example.txt`.
Files in `.tar`, `.tar.gz`, `.tar.bz`, and `.zip` formats can
also be extracted.
Passing a hash will verify the file after download. The command line
programs `shasum` and `sha256sum` can compute the hash.
Example:
```python
path_to_downloaded_file = get_file(
origin="https://storage.googleapis.com/download.tensorflow.org/example_images/flower_photos.tgz",
extract=True,
)
```
Args:
fname: Name of the file. If an absolute path, e.g. `"/path/to/file.txt"`
is specified, the file will be saved at that location.
If `None`, the name of the file at `origin` will be used.
origin: Original URL of the file.
untar: Deprecated in favor of `extract` argument.
boolean, whether the file should be decompressed
md5_hash: Deprecated in favor of `file_hash` argument.
md5 hash of the file for verification
file_hash: The expected hash string of the file after download.
The sha256 and md5 hash algorithms are both supported.
cache_subdir: Subdirectory under the Keras cache dir where the file is
saved. If an absolute path, e.g. `"/path/to/folder"` is
specified, the file will be saved at that location.
hash_algorithm: Select the hash algorithm to verify the file.
options are `"md5'`, `"sha256'`, and `"auto'`.
The default 'auto' detects the hash algorithm in use.
extract: True tries extracting the file as an Archive, like tar or zip.
archive_format: Archive format to try for extracting the file.
Options are `"auto'`, `"tar'`, `"zip'`, and `None`.
`"tar"` includes tar, tar.gz, and tar.bz files.
The default `"auto"` corresponds to `["tar", "zip"]`.
None or an empty list will return no matches found.
cache_dir: Location to store cached files, when None it
defaults to the default directory `~/.keras/`.
Returns:
Path to the downloaded file.
**⚠️ Warning on malicious downloads ⚠️**
Downloading something from the Internet carries a risk.
NEVER download a file/archive if you do not trust the source.
We recommend that you specify the `file_hash` argument
(if the hash of the source file is known) to make sure that the file you
are getting is the one you expect.
"""
if origin is None:
raise ValueError(
'Please specify the "origin" argument (URL of the file '
"to download)."
)
if cache_dir is None:
cache_dir = os.path.join(os.path.expanduser("~"), ".keras")
if md5_hash is not None and file_hash is None:
file_hash = md5_hash
hash_algorithm = "md5"
datadir_base = os.path.expanduser(cache_dir)
if not os.access(datadir_base, os.W_OK):
datadir_base = os.path.join("/tmp", ".keras")
datadir = os.path.join(datadir_base, cache_subdir)
os.makedirs(datadir, exist_ok=True)
fname = path_to_string(fname)
if not fname:
fname = os.path.basename(urllib.parse.urlsplit(origin).path)
if not fname:
raise ValueError(
"Can't parse the file name from the origin provided: "
f"'{origin}'."
"Please specify the `fname` as the input param."
)
if untar:
if fname.endswith(".tar.gz"):
fname = pathlib.Path(fname)
# The 2 `.with_suffix()` are because of `.tar.gz` as pathlib
# considers it as 2 suffixes.
fname = fname.with_suffix("").with_suffix("")
fname = str(fname)
untar_fpath = os.path.join(datadir, fname)
fpath = untar_fpath + ".tar.gz"
else:
fpath = os.path.join(datadir, fname)
download = False
if os.path.exists(fpath):
# File found; verify integrity if a hash was provided.
if file_hash is not None:
if not validate_file(fpath, file_hash, algorithm=hash_algorithm):
io_utils.print_msg(
"A local file was found, but it seems to be "
f"incomplete or outdated because the {hash_algorithm} "
"file hash does not match the original value of "
f"{file_hash} "
"so we will re-download the data."
)
download = True
else:
download = True
if download:
io_utils.print_msg(f"Downloading data from {origin}")
class DLProgbar:
"""Manage progress bar state for use in urlretrieve."""
def __init__(self):
self.progbar = None
self.finished = False
def __call__(self, block_num, block_size, total_size):
if not self.progbar:
if total_size == -1:
total_size = None
self.progbar = Progbar(total_size)
current = block_num * block_size
if total_size is None:
self.progbar.update(current)
else:
if current < total_size:
self.progbar.update(current)
elif not self.finished:
self.progbar.update(self.progbar.target)
self.finished = True
error_msg = "URL fetch failure on {}: {} -- {}"
try:
try:
urlretrieve(origin, fpath, DLProgbar())
except urllib.error.HTTPError as e:
raise Exception(error_msg.format(origin, e.code, e.msg))
except urllib.error.URLError as e:
raise Exception(error_msg.format(origin, e.errno, e.reason))
except (Exception, KeyboardInterrupt):
if os.path.exists(fpath):
os.remove(fpath)
raise
# Validate download if succeeded and user provided an expected hash
# Security conscious users would get the hash of the file from a
# separate channel and pass it to this API to prevent MITM / corruption:
if os.path.exists(fpath) and file_hash is not None:
if not validate_file(fpath, file_hash, algorithm=hash_algorithm):
raise ValueError(
"Incomplete or corrupted file detected. "
f"The {hash_algorithm} "
"file hash does not match the provided value "
f"of {file_hash}."
)
if untar:
if not os.path.exists(untar_fpath):
status = extract_archive(fpath, datadir, archive_format="tar")
if not status:
warnings.warn("Could not extract archive.", stacklevel=2)
return untar_fpath
if extract:
status = extract_archive(fpath, datadir, archive_format)
if not status:
warnings.warn("Could not extract archive.", stacklevel=2)
# TODO: return extracted fpath if we extracted an archive,
# rather than the archive path.
return fpath
def resolve_hasher(algorithm, file_hash=None):
"""Returns hash algorithm as hashlib function."""
if algorithm == "sha256":
return hashlib.sha256()
if algorithm == "auto" and file_hash is not None and len(file_hash) == 64:
return hashlib.sha256()
# This is used only for legacy purposes.
return hashlib.md5()
def hash_file(fpath, algorithm="sha256", chunk_size=65535):
"""Calculates a file sha256 or md5 hash.
Example:
>>> hash_file('/path/to/file.zip')
'e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855'
Args:
fpath: Path to the file being validated.
algorithm: Hash algorithm, one of `"auto"`, `"sha256"`, or `"md5"`.
The default `"auto"` detects the hash algorithm in use.
chunk_size: Bytes to read at a time, important for large files.
Returns:
The file hash.
"""
if isinstance(algorithm, str):
hasher = resolve_hasher(algorithm)
else:
hasher = algorithm
with open(fpath, "rb") as fpath_file:
for chunk in iter(lambda: fpath_file.read(chunk_size), b""):
hasher.update(chunk)
return hasher.hexdigest()
def validate_file(fpath, file_hash, algorithm="auto", chunk_size=65535):
"""Validates a file against a sha256 or md5 hash.
Args:
fpath: path to the file being validated
file_hash: The expected hash string of the file.
The sha256 and md5 hash algorithms are both supported.
algorithm: Hash algorithm, one of `"auto"`, `"sha256"`, or `"md5"`.
The default `"auto"` detects the hash algorithm in use.
chunk_size: Bytes to read at a time, important for large files.
Returns:
Boolean, whether the file is valid.
"""
hasher = resolve_hasher(algorithm, file_hash)
if str(hash_file(fpath, hasher, chunk_size)) == str(file_hash):
return True
else:
return False