file_download.py

import copy
import fnmatch
import inspect
import io
import json
import os
import re
import shutil
import stat
import tempfile
import time
import uuid
import warnings
from contextlib import contextmanager
from dataclasses import dataclass
from functools import partial
from pathlib import Path
from typing import Any, BinaryIO, Dict, Generator, Literal, Optional, Tuple, Union
from urllib.parse import quote, urlparse

import requests
from filelock import FileLock

from huggingface_hub import constants

from . import __version__  # noqa: F401 # for backward compatibility
from .constants import (
    DEFAULT_ETAG_TIMEOUT,
    DEFAULT_REQUEST_TIMEOUT,
    DEFAULT_REVISION,
    DOWNLOAD_CHUNK_SIZE,
    ENDPOINT,
    HF_HUB_CACHE,
    HF_HUB_DISABLE_SYMLINKS_WARNING,
    HF_HUB_DOWNLOAD_TIMEOUT,
    HF_HUB_ENABLE_HF_TRANSFER,
    HF_HUB_ETAG_TIMEOUT,
    HF_TRANSFER_CONCURRENCY,
    HUGGINGFACE_CO_URL_TEMPLATE,
    HUGGINGFACE_HEADER_X_LINKED_ETAG,
    HUGGINGFACE_HEADER_X_LINKED_SIZE,
    HUGGINGFACE_HEADER_X_REPO_COMMIT,
    HUGGINGFACE_HUB_CACHE,  # noqa: F401 # for backward compatibility
    REPO_ID_SEPARATOR,
    REPO_TYPES,
    REPO_TYPES_URL_PREFIXES,
)
from .utils import (
    EntryNotFoundError,
    FileMetadataError,
    GatedRepoError,
    LocalEntryNotFoundError,
    RepositoryNotFoundError,
    RevisionNotFoundError,
    SoftTemporaryDirectory,
    build_hf_headers,
    get_fastai_version,  # noqa: F401 # for backward compatibility
    get_fastcore_version,  # noqa: F401 # for backward compatibility
    get_graphviz_version,  # noqa: F401 # for backward compatibility
    get_jinja_version,  # noqa: F401 # for backward compatibility
    get_pydot_version,  # noqa: F401 # for backward compatibility
    get_session,
    get_tf_version,  # noqa: F401 # for backward compatibility
    get_torch_version,  # noqa: F401 # for backward compatibility
    hf_raise_for_status,
    is_fastai_available,  # noqa: F401 # for backward compatibility
    is_fastcore_available,  # noqa: F401 # for backward compatibility
    is_graphviz_available,  # noqa: F401 # for backward compatibility
    is_jinja_available,  # noqa: F401 # for backward compatibility
    is_pydot_available,  # noqa: F401 # for backward compatibility
    is_tf_available,  # noqa: F401 # for backward compatibility
    is_torch_available,  # noqa: F401 # for backward compatibility
    logging,
    reset_sessions,
    tqdm,
    validate_hf_hub_args,
)
from .utils._headers import _http_user_agent
from .utils._runtime import _PY_VERSION  # noqa: F401 # for backward compatibility
from .utils._typing import HTTP_METHOD_T
from .utils.insecure_hashlib import sha256


logger = logging.get_logger(__name__)

# Regex to get filename from a "Content-Disposition" header for CDN-served files
HEADER_FILENAME_PATTERN = re.compile(r'filename="(?P<filename>.*?)";')


_are_symlinks_supported_in_dir: Dict[str, bool] = {}


def are_symlinks_supported(cache_dir: Union[str, Path, None] = None) -> bool:
    """Return whether the symlinks are supported on the machine.

    Since symlinks support can change depending on the mounted disk, we need to check
    on the precise cache folder. By default, the default HF cache directory is checked.

    Args:
        cache_dir (`str`, `Path`, *optional*):
            Path to the folder where cached files are stored.

    Returns: [bool] Whether symlinks are supported in the directory.
    """
    # Defaults to HF cache
    if cache_dir is None:
        cache_dir = HF_HUB_CACHE
    cache_dir = str(Path(cache_dir).expanduser().resolve())  # make it unique

    # Check symlink compatibility only once (per cache directory) at first time use
    if cache_dir not in _are_symlinks_supported_in_dir:
        _are_symlinks_supported_in_dir[cache_dir] = True

        os.makedirs(cache_dir, exist_ok=True)
        with SoftTemporaryDirectory(dir=cache_dir) as tmpdir:
            src_path = Path(tmpdir) / "dummy_file_src"
            src_path.touch()
            dst_path = Path(tmpdir) / "dummy_file_dst"

            # Relative source path as in `_create_symlink``
            relative_src = os.path.relpath(src_path, start=os.path.dirname(dst_path))
            try:
                os.symlink(relative_src, dst_path)
            except OSError:
                # Likely running on Windows
                _are_symlinks_supported_in_dir[cache_dir] = False

                if not HF_HUB_DISABLE_SYMLINKS_WARNING:
                    message = (
                        "`huggingface_hub` cache-system uses symlinks by default to"
                        " efficiently store duplicated files but your machine does not"
                        f" support them in {cache_dir}. Caching files will still work"
                        " but in a degraded version that might require more space on"
                        " your disk. This warning can be disabled by setting the"
                        " `HF_HUB_DISABLE_SYMLINKS_WARNING` environment variable. For"
                        " more details, see"
                        " https://huggingface.co/docs/huggingface_hub/how-to-cache#limitations."
                    )
                    if os.name == "nt":
                        message += (
                            "\nTo support symlinks on Windows, you either need to"
                            " activate Developer Mode or to run Python as an"
                            " administrator. In order to see activate developer mode,"
                            " see this article:"
                            " https://docs.microsoft.com/en-us/windows/apps/get-started/enable-your-device-for-development"
                        )
                    warnings.warn(message)

    return _are_symlinks_supported_in_dir[cache_dir]


# Return value when trying to load a file from cache but the file does not exist in the distant repo.
_CACHED_NO_EXIST = object()
_CACHED_NO_EXIST_T = Any
REGEX_COMMIT_HASH = re.compile(r"^[0-9a-f]{40}$")


@dataclass(frozen=True)
class HfFileMetadata:
    """Data structure containing information about a file versioned on the Hub.

    Returned by [`get_hf_file_metadata`] based on a URL.

    Args:
        commit_hash (`str`, *optional*):
            The commit_hash related to the file.
        etag (`str`, *optional*):
            Etag of the file on the server.
        location (`str`):
            Location where to download the file. Can be a Hub url or not (CDN).
        size (`size`):
            Size of the file. In case of an LFS file, contains the size of the actual
            LFS file, not the pointer.
    """

    commit_hash: Optional[str]
    etag: Optional[str]
    location: str
    size: Optional[int]


@validate_hf_hub_args
def hf_hub_url(
    repo_id: str,
    filename: str,
    *,
    subfolder: Optional[str] = None,
    repo_type: Optional[str] = None,
    revision: Optional[str] = None,
    endpoint: Optional[str] = None,
) -> str:
    """Construct the URL of a file from the given information.

    The resolved address can either be a huggingface.co-hosted url, or a link to
    Cloudfront (a Content Delivery Network, or CDN) for large files which are
    more than a few MBs.

    Args:
        repo_id (`str`):
            A namespace (user or an organization) name and a repo name separated
            by a `/`.
        filename (`str`):
            The name of the file in the repo.
        subfolder (`str`, *optional*):
            An optional value corresponding to a folder inside the repo.
        repo_type (`str`, *optional*):
            Set to `"dataset"` or `"space"` if downloading from a dataset or space,
            `None` or `"model"` if downloading from a model. Default is `None`.
        revision (`str`, *optional*):
            An optional Git revision id which can be a branch name, a tag, or a
            commit hash.

    Example:

    ```python
    >>> from huggingface_hub import hf_hub_url

    >>> hf_hub_url(
    ...     repo_id="julien-c/EsperBERTo-small", filename="pytorch_model.bin"
    ... )
    'https://huggingface.co/julien-c/EsperBERTo-small/resolve/main/pytorch_model.bin'
    ```

    <Tip>

    Notes:

        Cloudfront is replicated over the globe so downloads are way faster for
        the end user (and it also lowers our bandwidth costs).

        Cloudfront aggressively caches files by default (default TTL is 24
        hours), however this is not an issue here because we implement a
        git-based versioning system on huggingface.co, which means that we store
        the files on S3/Cloudfront in a content-addressable way (i.e., the file
        name is its hash). Using content-addressable filenames means cache can't
        ever be stale.

        In terms of client-side caching from this library, we base our caching
        on the objects' entity tag (`ETag`), which is an identifier of a
        specific version of a resource [1]_. An object's ETag is: its git-sha1
        if stored in git, or its sha256 if stored in git-lfs.

    </Tip>

    References:

    -  [1] https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/ETag
    """
    if subfolder == "":
        subfolder = None
    if subfolder is not None:
        filename = f"{subfolder}/{filename}"

    if repo_type not in REPO_TYPES:
        raise ValueError("Invalid repo type")

    if repo_type in REPO_TYPES_URL_PREFIXES:
        repo_id = REPO_TYPES_URL_PREFIXES[repo_type] + repo_id

    if revision is None:
        revision = DEFAULT_REVISION
    url = HUGGINGFACE_CO_URL_TEMPLATE.format(
        repo_id=repo_id, revision=quote(revision, safe=""), filename=quote(filename)
    )
    # Update endpoint if provided
    if endpoint is not None and url.startswith(ENDPOINT):
        url = endpoint + url[len(ENDPOINT) :]
    return url


def url_to_filename(url: str, etag: Optional[str] = None) -> str:
    """Generate a local filename from a url.

    Convert `url` into a hashed filename in a reproducible way. If `etag` is
    specified, append its hash to the url's, delimited by a period. If the url
    ends with .h5 (Keras HDF5 weights) adds '.h5' to the name so that TF 2.0 can
    identify it as a HDF5 file (see
    https://github.com/tensorflow/tensorflow/blob/00fad90125b18b80fe054de1055770cfb8fe4ba3/tensorflow/python/keras/engine/network.py#L1380)

    Args:
        url (`str`):
            The address to the file.
        etag (`str`, *optional*):
            The ETag of the file.

    Returns:
        The generated filename.
    """
    url_bytes = url.encode("utf-8")
    filename = sha256(url_bytes).hexdigest()

    if etag:
        etag_bytes = etag.encode("utf-8")
        filename += "." + sha256(etag_bytes).hexdigest()

    if url.endswith(".h5"):
        filename += ".h5"

    return filename


def filename_to_url(
    filename,
    cache_dir: Optional[str] = None,
    legacy_cache_layout: bool = False,
) -> Tuple[str, str]:
    """
    Return the url and etag (which may be `None`) stored for `filename`. Raise
    `EnvironmentError` if `filename` or its stored metadata do not exist.

    Args:
        filename (`str`):
            The name of the file
        cache_dir (`str`, *optional*):
            The cache directory to use instead of the default one.
        legacy_cache_layout (`bool`, *optional*, defaults to `False`):
            If `True`, uses the legacy file cache layout i.e. just call `hf_hub_url`
            then `cached_download`. This is deprecated as the new cache layout is
            more powerful.
    """
    if not legacy_cache_layout:
        warnings.warn(
            "`filename_to_url` uses the legacy way cache file layout",
            FutureWarning,
        )

    if cache_dir is None:
        cache_dir = HF_HUB_CACHE
    if isinstance(cache_dir, Path):
        cache_dir = str(cache_dir)

    cache_path = os.path.join(cache_dir, filename)
    if not os.path.exists(cache_path):
        raise EnvironmentError(f"file {cache_path} not found")

    meta_path = cache_path + ".json"
    if not os.path.exists(meta_path):
        raise EnvironmentError(f"file {meta_path} not found")

    with open(meta_path, encoding="utf-8") as meta_file:
        metadata = json.load(meta_file)
    url = metadata["url"]
    etag = metadata["etag"]

    return url, etag


def http_user_agent(
    *,
    library_name: Optional[str] = None,
    library_version: Optional[str] = None,
    user_agent: Union[Dict, str, None] = None,
) -> str:
    """Deprecated in favor of [`build_hf_headers`]."""
    return _http_user_agent(
        library_name=library_name,
        library_version=library_version,
        user_agent=user_agent,
    )


class OfflineModeIsEnabled(ConnectionError):
    pass


def _raise_if_offline_mode_is_enabled(msg: Optional[str] = None):
    """Raise a OfflineModeIsEnabled error (subclass of ConnectionError) if
    HF_HUB_OFFLINE is True."""
    if constants.HF_HUB_OFFLINE:
        raise OfflineModeIsEnabled(
            "Offline mode is enabled." if msg is None else "Offline mode is enabled. " + str(msg)
        )


def _request_wrapper(
    method: HTTP_METHOD_T, url: str, *, follow_relative_redirects: bool = False, **params
) -> requests.Response:
    """Wrapper around requests methods to add several features.

    What it does:
    1. Ensure offline mode is disabled (env variable `HF_HUB_OFFLINE` not set to 1). If enabled, a
       `OfflineModeIsEnabled` exception is raised.
    2. Follow relative redirects if `follow_relative_redirects=True` even when `allow_redirection=False`.

    Args:
        method (`str`):
            HTTP method, such as 'GET' or 'HEAD'.
        url (`str`):
            The URL of the resource to fetch.
        follow_relative_redirects (`bool`, *optional*, defaults to `False`)
            If True, relative redirection (redirection to the same site) will be resolved even when `allow_redirection`
            kwarg is set to False. Useful when we want to follow a redirection to a renamed repository without
            following redirection to a CDN.
        **params (`dict`, *optional*):
            Params to pass to `requests.request`.
    """
    # 1. Check online mode
    _raise_if_offline_mode_is_enabled(f"Tried to reach {url}")

    # 2. Force relative redirection
    if follow_relative_redirects:
        response = _request_wrapper(
            method=method,
            url=url,
            follow_relative_redirects=False,
            **params,
        )

        # If redirection, we redirect only relative paths.
        # This is useful in case of a renamed repository.
        if 300 <= response.status_code <= 399:
            parsed_target = urlparse(response.headers["Location"])
            if parsed_target.netloc == "":
                # This means it is a relative 'location' headers, as allowed by RFC 7231.
                # (e.g. '/path/to/resource' instead of 'http://domain.tld/path/to/resource')
                # We want to follow this relative redirect !
                #
                # Highly inspired by `resolve_redirects` from requests library.
                # See https://github.com/psf/requests/blob/main/requests/sessions.py#L159
                next_url = urlparse(url)._replace(path=parsed_target.path).geturl()
                return _request_wrapper(method=method, url=next_url, follow_relative_redirects=True, **params)
        return response

    # Perform request and return if status_code is not in the retry list.
    response = get_session().request(method=method, url=url, **params)
    hf_raise_for_status(response)
    return response


def http_get(
    url: str,
    temp_file: BinaryIO,
    *,
    proxies=None,
    resume_size: float = 0,
    headers: Optional[Dict[str, str]] = None,
    expected_size: Optional[int] = None,
    _nb_retries: int = 5,
):
    """
    Download a remote file. Do not gobble up errors, and will return errors tailored to the Hugging Face Hub.

    If ConnectionError (SSLError) or ReadTimeout happen while streaming data from the server, it is most likely a
    transient error (network outage?). We log a warning message and try to resume the download a few times before
    giving up. The method gives up after 5 attempts if no new data has being received from the server.
    """
    hf_transfer = None
    if HF_HUB_ENABLE_HF_TRANSFER:
        if resume_size != 0:
            warnings.warn("'hf_transfer' does not support `resume_size`: falling back to regular download method")
        elif proxies is not None:
            warnings.warn("'hf_transfer' does not support `proxies`: falling back to regular download method")
        else:
            try:
                import hf_transfer  # type: ignore[no-redef]
            except ImportError:
                raise ValueError(
                    "Fast download using 'hf_transfer' is enabled"
                    " (HF_HUB_ENABLE_HF_TRANSFER=1) but 'hf_transfer' package is not"
                    " available in your environment. Try `pip install hf_transfer`."
                )

    initial_headers = headers
    headers = copy.deepcopy(headers) or {}
    if resume_size > 0:
        headers["Range"] = "bytes=%d-" % (resume_size,)

    r = _request_wrapper(
        method="GET", url=url, stream=True, proxies=proxies, headers=headers, timeout=HF_HUB_DOWNLOAD_TIMEOUT
    )
    hf_raise_for_status(r)
    content_length = r.headers.get("Content-Length")

    # NOTE: 'total' is the total number of bytes to download, not the number of bytes in the file.
    #       If the file is compressed, the number of bytes in the saved file will be higher than 'total'.
    total = resume_size + int(content_length) if content_length is not None else None

    displayed_name = url
    content_disposition = r.headers.get("Content-Disposition")
    if content_disposition is not None:
        match = HEADER_FILENAME_PATTERN.search(content_disposition)
        if match is not None:
            # Means file is on CDN
            displayed_name = match.groupdict()["filename"]

    # Truncate filename if too long to display
    if len(displayed_name) > 40:
        displayed_name = f"(…){displayed_name[-40:]}"

    consistency_error_message = (
        f"Consistency check failed: file should be of size {expected_size} but has size"
        f" {{actual_size}} ({displayed_name}).\nWe are sorry for the inconvenience. Please retry download and"
        " pass `force_download=True, resume_download=False` as argument.\nIf the issue persists, please let us"
        " know by opening an issue on https://github.com/huggingface/huggingface_hub."
    )

    # Stream file to buffer
    with tqdm(
        unit="B",
        unit_scale=True,
        total=total,
        initial=resume_size,
        desc=displayed_name,
        disable=bool(logger.getEffectiveLevel() == logging.NOTSET),
    ) as progress:
        if hf_transfer and total is not None and total > 5 * DOWNLOAD_CHUNK_SIZE:
            supports_callback = "callback" in inspect.signature(hf_transfer.download).parameters
            if not supports_callback:
                warnings.warn(
                    "You are using an outdated version of `hf_transfer`. "
                    "Consider upgrading to latest version to enable progress bars "
                    "using `pip install -U hf_transfer`."
                )
            try:
                hf_transfer.download(
                    url=url,
                    filename=temp_file.name,
                    max_files=HF_TRANSFER_CONCURRENCY,
                    chunk_size=DOWNLOAD_CHUNK_SIZE,
                    headers=headers,
                    parallel_failures=3,
                    max_retries=5,
                    **({"callback": progress.update} if supports_callback else {}),
                )
            except Exception as e:
                raise RuntimeError(
                    "An error occurred while downloading using `hf_transfer`. Consider"
                    " disabling HF_HUB_ENABLE_HF_TRANSFER for better error handling."
                ) from e
            if not supports_callback:
                progress.update(total)
            if expected_size is not None and expected_size != os.path.getsize(temp_file.name):
                raise EnvironmentError(
                    consistency_error_message.format(
                        actual_size=os.path.getsize(temp_file.name),
                    )
                )
            return
        new_resume_size = resume_size
        try:
            for chunk in r.iter_content(chunk_size=DOWNLOAD_CHUNK_SIZE):
                if chunk:  # filter out keep-alive new chunks
                    progress.update(len(chunk))
                    temp_file.write(chunk)
                    new_resume_size += len(chunk)
                    # Some data has been downloaded from the server so we reset the number of retries.
                    _nb_retries = 5
        except (requests.ConnectionError, requests.ReadTimeout) as e:
            # If ConnectionError (SSLError) or ReadTimeout happen while streaming data from the server, it is most likely
            # a transient error (network outage?). We log a warning message and try to resume the download a few times
            # before giving up. Tre retry mechanism is basic but should be enough in most cases.
            if _nb_retries <= 0:
                logger.warning("Error while downloading from %s: %s\nMax retries exceeded.", url, str(e))
                raise
            logger.warning("Error while downloading from %s: %s\nTrying to resume download...", url, str(e))
            time.sleep(1)
            reset_sessions()  # In case of SSLError it's best to reset the shared requests.Session objects
            return http_get(
                url=url,
                temp_file=temp_file,
                proxies=proxies,
                resume_size=new_resume_size,
                headers=initial_headers,
                expected_size=expected_size,
                _nb_retries=_nb_retries - 1,
            )

        if expected_size is not None and expected_size != temp_file.tell():
            raise EnvironmentError(
                consistency_error_message.format(
                    actual_size=temp_file.tell(),
                )
            )


@validate_hf_hub_args
def cached_download(
    url: str,
    *,
    library_name: Optional[str] = None,
    library_version: Optional[str] = None,
    cache_dir: Union[str, Path, None] = None,
    user_agent: Union[Dict, str, None] = None,
    force_download: bool = False,
    force_filename: Optional[str] = None,
    proxies: Optional[Dict] = None,
    etag_timeout: float = DEFAULT_ETAG_TIMEOUT,
    resume_download: bool = False,
    token: Union[bool, str, None] = None,
    local_files_only: bool = False,
    legacy_cache_layout: bool = False,
) -> str:
    """
    Download from a given URL and cache it if it's not already present in the
    local cache.

    Given a URL, this function looks for the corresponding file in the local
    cache. If it's not there, download it. Then return the path to the cached
    file.

    Will raise errors tailored to the Hugging Face Hub.

    Args:
        url (`str`):
            The path to the file to be downloaded.
        library_name (`str`, *optional*):
            The name of the library to which the object corresponds.
        library_version (`str`, *optional*):
            The version of the library.
        cache_dir (`str`, `Path`, *optional*):
            Path to the folder where cached files are stored.
        user_agent (`dict`, `str`, *optional*):
            The user-agent info in the form of a dictionary or a string.
        force_download (`bool`, *optional*, defaults to `False`):
            Whether the file should be downloaded even if it already exists in
            the local cache.
        force_filename (`str`, *optional*):
            Use this name instead of a generated file name.
        proxies (`dict`, *optional*):
            Dictionary mapping protocol to the URL of the proxy passed to
            `requests.request`.
        etag_timeout (`float`, *optional* defaults to `10`):
            When fetching ETag, how many seconds to wait for the server to send
            data before giving up which is passed to `requests.request`.
        resume_download (`bool`, *optional*, defaults to `False`):
            If `True`, resume a previously interrupted download.
        token (`bool`, `str`, *optional*):
            A token to be used for the download.
                - If `True`, the token is read from the HuggingFace config
                  folder.
                - If a string, it's used as the authentication token.
        local_files_only (`bool`, *optional*, defaults to `False`):
            If `True`, avoid downloading the file and return the path to the
            local cached file if it exists.
        legacy_cache_layout (`bool`, *optional*, defaults to `False`):
            Set this parameter to `True` to mention that you'd like to continue
            the old cache layout. Putting this to `True` manually will not raise
            any warning when using `cached_download`. We recommend using
            `hf_hub_download` to take advantage of the new cache.

    Returns:
        Local path (string) of file or if networking is off, last version of
        file cached on disk.

    <Tip>

    Raises the following errors:

        - [`EnvironmentError`](https://docs.python.org/3/library/exceptions.html#EnvironmentError)
          if `token=True` and the token cannot be found.
        - [`OSError`](https://docs.python.org/3/library/exceptions.html#OSError)
          if ETag cannot be determined.
        - [`ValueError`](https://docs.python.org/3/library/exceptions.html#ValueError)
          if some parameter value is invalid
        - [`~utils.RepositoryNotFoundError`]
          If the repository to download from cannot be found. This may be because it doesn't exist,
          or because it is set to `private` and you do not have access.
        - [`~utils.RevisionNotFoundError`]
          If the revision to download from cannot be found.
        - [`~utils.EntryNotFoundError`]
          If the file to download cannot be found.
        - [`~utils.LocalEntryNotFoundError`]
          If network is disabled or unavailable and file is not found in cache.

    </Tip>
    """
    if HF_HUB_ETAG_TIMEOUT != DEFAULT_ETAG_TIMEOUT:
        # Respect environment variable above user value
        etag_timeout = HF_HUB_ETAG_TIMEOUT

    if not legacy_cache_layout:
        warnings.warn(
            "'cached_download' is the legacy way to download files from the HF hub, please consider upgrading to"
            " 'hf_hub_download'",
            FutureWarning,
        )

    if cache_dir is None:
        cache_dir = HF_HUB_CACHE
    if isinstance(cache_dir, Path):
        cache_dir = str(cache_dir)

    os.makedirs(cache_dir, exist_ok=True)

    headers = build_hf_headers(
        token=token,
        library_name=library_name,
        library_version=library_version,
        user_agent=user_agent,
    )

    url_to_download = url
    etag = None
    expected_size = None
    if not local_files_only:
        try:
            # Temporary header: we want the full (decompressed) content size returned to be able to check the
            # downloaded file size
            headers["Accept-Encoding"] = "identity"
            r = _request_wrapper(
                method="HEAD",
                url=url,
                headers=headers,
                allow_redirects=False,
                follow_relative_redirects=True,
                proxies=proxies,
                timeout=etag_timeout,
            )
            headers.pop("Accept-Encoding", None)
            hf_raise_for_status(r)
            etag = r.headers.get(HUGGINGFACE_HEADER_X_LINKED_ETAG) or r.headers.get("ETag")
            # We favor a custom header indicating the etag of the linked resource, and
            # we fallback to the regular etag header.
            # If we don't have any of those, raise an error.
            if etag is None:
                raise FileMetadataError(
                    "Distant resource does not have an ETag, we won't be able to reliably ensure reproducibility."
                )
            # We get the expected size of the file, to check the download went well.
            expected_size = _int_or_none(r.headers.get("Content-Length"))
            # In case of a redirect, save an extra redirect on the request.get call,
            # and ensure we download the exact atomic version even if it changed
            # between the HEAD and the GET (unlikely, but hey).
            # Useful for lfs blobs that are stored on a CDN.
            if 300 <= r.status_code <= 399:
                url_to_download = r.headers["Location"]
                headers.pop("authorization", None)
                expected_size = None  # redirected -> can't know the expected size
        except (requests.exceptions.SSLError, requests.exceptions.ProxyError):
            # Actually raise for those subclasses of ConnectionError
            raise
        except (
            requests.exceptions.ConnectionError,
            requests.exceptions.Timeout,
            OfflineModeIsEnabled,
        ):
            # Otherwise, our Internet connection is down.
            # etag is None
            pass

    filename = force_filename if force_filename is not None else url_to_filename(url, etag)

    # get cache path to put the file
    cache_path = os.path.join(cache_dir, filename)

    # etag is None == we don't have a connection or we passed local_files_only.
    # try to get the last downloaded one
    if etag is None:
        if os.path.exists(cache_path) and not force_download:
            return cache_path
        else:
            matching_files = [
                file
                for file in fnmatch.filter(os.listdir(cache_dir), filename.split(".")[0] + ".*")
                if not file.endswith(".json") and not file.endswith(".lock")
            ]
            if len(matching_files) > 0 and not force_download and force_filename is None:
                return os.path.join(cache_dir, matching_files[-1])
            else:
                # If files cannot be found and local_files_only=True,
                # the models might've been found if local_files_only=False
                # Notify the user about that
                if local_files_only:
                    raise LocalEntryNotFoundError(
                        "Cannot find the requested files in the cached path and"
                        " outgoing traffic has been disabled. To enable model look-ups"
                        " and downloads online, set 'local_files_only' to False."
                    )
                else:
                    raise LocalEntryNotFoundError(
                        "Connection error, and we cannot find the requested files in"
                        " the cached path. Please try again or make sure your Internet"
                        " connection is on."
                    )

    # From now on, etag is not None.
    if os.path.exists(cache_path) and not force_download:
        return cache_path

    # Prevent parallel downloads of the same file with a lock.
    lock_path = cache_path + ".lock"

    # Some Windows versions do not allow for paths longer than 255 characters.
    # In this case, we must specify it is an extended path by using the "\\?\" prefix.
    if os.name == "nt" and len(os.path.abspath(lock_path)) > 255:
        lock_path = "\\\\?\\" + os.path.abspath(lock_path)

    if os.name == "nt" and len(os.path.abspath(cache_path)) > 255:
        cache_path = "\\\\?\\" + os.path.abspath(cache_path)

    with FileLock(lock_path):
        # If the download just completed while the lock was activated.
        if os.path.exists(cache_path) and not force_download:
            # Even if returning early like here, the lock will be released.
            return cache_path

        if resume_download:
            incomplete_path = cache_path + ".incomplete"

            @contextmanager
            def _resumable_file_manager() -> Generator[io.BufferedWriter, None, None]:
                with open(incomplete_path, "ab") as f:
                    yield f

            temp_file_manager = _resumable_file_manager
            if os.path.exists(incomplete_path):
                resume_size = os.stat(incomplete_path).st_size
            else:
                resume_size = 0
        else:
            temp_file_manager = partial(  # type: ignore
                tempfile.NamedTemporaryFile, mode="wb", dir=cache_dir, delete=False
            )
            resume_size = 0

        # Download to temporary file, then copy to cache dir once finished.
        # Otherwise you get corrupt cache entries if the download gets interrupted.
        with temp_file_manager() as temp_file:
            logger.info("downloading %s to %s", url, temp_file.name)

            http_get(
                url_to_download,
                temp_file,
                proxies=proxies,
                resume_size=resume_size,
                headers=headers,
                expected_size=expected_size,
            )

        logger.info("storing %s in cache at %s", url, cache_path)
        _chmod_and_replace(temp_file.name, cache_path)

        if force_filename is None:
            logger.info("creating metadata file for %s", cache_path)
            meta = {"url": url, "etag": etag}
            meta_path = cache_path + ".json"
            with open(meta_path, "w") as meta_file:
                json.dump(meta, meta_file)

    return cache_path


def _normalize_etag(etag: Optional[str]) -> Optional[str]:
    """Normalize ETag HTTP header, so it can be used to create nice filepaths.

    The HTTP spec allows two forms of ETag:
      ETag: W/"<etag_value>"
      ETag: "<etag_value>"

    For now, we only expect the second form from the server, but we want to be future-proof so we support both. For
    more context, see `TestNormalizeEtag` tests and https://github.com/huggingface/huggingface_hub/pull/1428.

    Args:
        etag (`str`, *optional*): HTTP header

    Returns:
        `str` or `None`: string that can be used as a nice directory name.
        Returns `None` if input is None.
    """
    if etag is None:
        return None
    return etag.lstrip("W/").strip('"')


def _create_relative_symlink(src: str, dst: str, new_blob: bool = False) -> None:
    """Alias method used in `transformers` conversion script."""
    return _create_symlink(src=src, dst=dst, new_blob=new_blob)


def _create_symlink(src: str, dst: str, new_blob: bool = False) -> None:
    """Create a symbolic link named dst pointing to src.

    By default, it will try to create a symlink using a relative path. Relative paths have 2 advantages:
    - If the cache_folder is moved (example: back-up on a shared drive), relative paths within the cache folder will
      not brake.
    - Relative paths seems to be better handled on Windows. Issue was reported 3 times in less than a week when
      changing from relative to absolute paths. See https://github.com/huggingface/huggingface_hub/issues/1398,
      https://github.com/huggingface/diffusers/issues/2729 and https://github.com/huggingface/transformers/pull/22228.
      NOTE: The issue with absolute paths doesn't happen on admin mode.
    When creating a symlink from the cache to a local folder, it is possible that a relative path cannot be created.
    This happens when paths are not on the same volume. In that case, we use absolute paths.


    The result layout looks something like
        └── [ 128]  snapshots
            ├── [ 128]  2439f60ef33a0d46d85da5001d52aeda5b00ce9f
            │   ├── [  52]  README.md -> ../../../blobs/d7edf6bd2a681fb0175f7735299831ee1b22b812
            │   └── [  76]  pytorch_model.bin -> ../../../blobs/403450e234d65943a7dcf7e05a771ce3c92faa84dd07db4ac20f592037a1e4bd

    If symlinks cannot be created on this platform (most likely to be Windows), the workaround is to avoid symlinks by
    having the actual file in `dst`. If it is a new file (`new_blob=True`), we move it to `dst`. If it is not a new file
    (`new_blob=False`), we don't know if the blob file is already referenced elsewhere. To avoid breaking existing
    cache, the file is duplicated on the disk.

    In case symlinks are not supported, a warning message is displayed to the user once when loading `huggingface_hub`.
    The warning message can be disable with the `DISABLE_SYMLINKS_WARNING` environment variable.
    """
    try:
        os.remove(dst)
    except OSError:
        pass

    abs_src = os.path.abspath(os.path.expanduser(src))
    abs_dst = os.path.abspath(os.path.expanduser(dst))

    # Use relative_dst in priority
    try:
        relative_src = os.path.relpath(abs_src, os.path.dirname(abs_dst))
    except ValueError:
        # Raised on Windows if src and dst are not on the same volume. This is the case when creating a symlink to a
        # local_dir instead of within the cache directory.
        # See https://docs.python.org/3/library/os.path.html#os.path.relpath
        relative_src = None

    try:
        try:
            commonpath = os.path.commonpath([abs_src, abs_dst])
            _support_symlinks = are_symlinks_supported(os.path.dirname(commonpath))
        except ValueError:
            # Raised if src and dst are not on the same volume. Symlinks will still work on Linux/Macos.
            # See https://docs.python.org/3/library/os.path.html#os.path.commonpath
            _support_symlinks = os.name != "nt"
    except PermissionError:
        # Permission error means src and dst are not in the same volume (e.g. destination path has been provided
        # by the user via `local_dir`. Let's test symlink support there)
        _support_symlinks = are_symlinks_supported(os.path.dirname(abs_dst))

    if _support_symlinks:
        src_rel_or_abs = relative_src or abs_src
        logger.debug(f"Creating pointer from {src_rel_or_abs} to {abs_dst}")
        try:
            os.symlink(src_rel_or_abs, abs_dst)
        except FileExistsError:
            if os.path.islink(abs_dst) and os.path.realpath(abs_dst) == os.path.realpath(abs_src):
                # `abs_dst` already exists and is a symlink to the `abs_src` blob. It is most likely that the file has
                # been cached twice concurrently (exactly between `os.remove` and `os.symlink`). Do nothing.
                pass
            else:
                # Very unlikely to happen. Means a file `dst` has been created exactly between `os.remove` and
                # `os.symlink` and is not a symlink to the `abs_src` blob file. Raise exception.
                raise
    elif new_blob:
        logger.info(f"Symlink not supported. Moving file from {abs_src} to {abs_dst}")
        shutil.move(src, dst)
    else:
        logger.info(f"Symlink not supported. Copying file from {abs_src} to {abs_dst}")
        shutil.copyfile(src, dst)


def _cache_commit_hash_for_specific_revision(storage_folder: str, revision: str, commit_hash: str) -> None:
    """Cache reference between a revision (tag, branch or truncated commit hash) and the corresponding commit hash.

    Does nothing if `revision` is already a proper `commit_hash` or reference is already cached.
    """
    if revision != commit_hash:
        ref_path = Path(storage_folder) / "refs" / revision
        ref_path.parent.mkdir(parents=True, exist_ok=True)
        if not ref_path.exists() or commit_hash != ref_path.read_text():
            # Update ref only if has been updated. Could cause useless error in case
            # repo is already cached and user doesn't have write access to cache folder.
            # See https://github.com/huggingface/huggingface_hub/issues/1216.
            ref_path.write_text(commit_hash)


@validate_hf_hub_args
def repo_folder_name(*, repo_id: str, repo_type: str) -> str:
    """Return a serialized version of a hf.co repo name and type, safe for disk storage
    as a single non-nested folder.

    Example: models--julien-c--EsperBERTo-small
    """
    # remove all `/` occurrences to correctly convert repo to directory name
    parts = [f"{repo_type}s", *repo_id.split("/")]
    return REPO_ID_SEPARATOR.join(parts)


def _check_disk_space(expected_size: int, target_dir: Union[str, Path]) -> None:
    """Check disk usage and log a warning if there is not enough disk space to download the file.

    Args:
        expected_size (`int`):
            The expected size of the file in bytes.
        target_dir (`str`):
            The directory where the file will be stored after downloading.
    """

    target_dir = Path(target_dir)  # format as `Path`
    for path in [target_dir] + list(target_dir.parents):  # first check target_dir, then each parents one by one
        try:
            target_dir_free = shutil.disk_usage(path).free
            if target_dir_free < expected_size:
                warnings.warn(
                    "Not enough free disk space to download the file. "
                    f"The expected file size is: {expected_size / 1e6:.2f} MB. "
                    f"The target location {target_dir} only has {target_dir_free / 1e6:.2f} MB free disk space."
                )
            return
        except OSError:  # raise on anything: file does not exist or space disk cannot be checked
            pass


@validate_hf_hub_args
def hf_hub_download(
    repo_id: str,
    filename: str,
    *,
    subfolder: Optional[str] = None,
    repo_type: Optional[str] = None,
    revision: Optional[str] = None,
    library_name: Optional[str] = None,
    library_version: Optional[str] = None,
    cache_dir: Union[str, Path, None] = None,
    local_dir: Union[str, Path, None] = None,
    local_dir_use_symlinks: Union[bool, Literal["auto"]] = "auto",
    user_agent: Union[Dict, str, None] = None,
    force_download: bool = False,
    force_filename: Optional[str] = None,
    proxies: Optional[Dict] = None,
    etag_timeout: float = DEFAULT_ETAG_TIMEOUT,
    resume_download: bool = False,
    token: Union[bool, str, None] = None,
    local_files_only: bool = False,
    legacy_cache_layout: bool = False,
    endpoint: Optional[str] = None,
) -> str:
    """Download a given file if it's not already present in the local cache.

    The new cache file layout looks like this:
    - The cache directory contains one subfolder per repo_id (namespaced by repo type)
    - inside each repo folder:
        - refs is a list of the latest known revision => commit_hash pairs
        - blobs contains the actual file blobs (identified by their git-sha or sha256, depending on
          whether they're LFS files or not)
        - snapshots contains one subfolder per commit, each "commit" contains the subset of the files
          that have been resolved at that particular commit. Each filename is a symlink to the blob
          at that particular commit.

    If `local_dir` is provided, the file structure from the repo will be replicated in this location. You can configure
    how you want to move those files:
      - If `local_dir_use_symlinks="auto"` (default), files are downloaded and stored in the cache directory as blob
        files. Small files (<5MB) are duplicated in `local_dir` while a symlink is created for bigger files. The goal
        is to be able to manually edit and save small files without corrupting the cache while saving disk space for
        binary files. The 5MB threshold can be configured with the `HF_HUB_LOCAL_DIR_AUTO_SYMLINK_THRESHOLD`
        environment variable.
      - If `local_dir_use_symlinks=True`, files are downloaded, stored in the cache directory and symlinked in `local_dir`.
        This is optimal in term of disk usage but files must not be manually edited.
      - If `local_dir_use_symlinks=False` and the blob files exist in the cache directory, they are duplicated in the
        local dir. This means disk usage is not optimized.
      - Finally, if `local_dir_use_symlinks=False` and the blob files do not exist in the cache directory, then the
        files are downloaded and directly placed under `local_dir`. This means if you need to download them again later,
        they will be re-downloaded entirely.

    ```
    [  96]  .
    └── [ 160]  models--julien-c--EsperBERTo-small
        ├── [ 160]  blobs
        │   ├── [321M]  403450e234d65943a7dcf7e05a771ce3c92faa84dd07db4ac20f592037a1e4bd
        │   ├── [ 398]  7cb18dc9bafbfcf74629a4b760af1b160957a83e
        │   └── [1.4K]  d7edf6bd2a681fb0175f7735299831ee1b22b812
        ├── [  96]  refs
        │   └── [  40]  main
        └── [ 128]  snapshots
            ├── [ 128]  2439f60ef33a0d46d85da5001d52aeda5b00ce9f
            │   ├── [  52]  README.md -> ../../blobs/d7edf6bd2a681fb0175f7735299831ee1b22b812
            │   └── [  76]  pytorch_model.bin -> ../../blobs/403450e234d65943a7dcf7e05a771ce3c92faa84dd07db4ac20f592037a1e4bd
            └── [ 128]  bbc77c8132af1cc5cf678da3f1ddf2de43606d48
                ├── [  52]  README.md -> ../../blobs/7cb18dc9bafbfcf74629a4b760af1b160957a83e
                └── [  76]  pytorch_model.bin -> ../../blobs/403450e234d65943a7dcf7e05a771ce3c92faa84dd07db4ac20f592037a1e4bd
    ```

    Args:
        repo_id (`str`):
            A user or an organization name and a repo name separated by a `/`.
        filename (`str`):
            The name of the file in the repo.
        subfolder (`str`, *optional*):
            An optional value corresponding to a folder inside the model repo.
        repo_type (`str`, *optional*):
            Set to `"dataset"` or `"space"` if downloading from a dataset or space,
            `None` or `"model"` if downloading from a model. Default is `None`.
        revision (`str`, *optional*):
            An optional Git revision id which can be a branch name, a tag, or a
            commit hash.
        library_name (`str`, *optional*):
            The name of the library to which the object corresponds.
        library_version (`str`, *optional*):
            The version of the library.
        cache_dir (`str`, `Path`, *optional*):
            Path to the folder where cached files are stored.
        local_dir (`str` or `Path`, *optional*):
            If provided, the downloaded file will be placed under this directory, either as a symlink (default) or
            a regular file (see description for more details).
        local_dir_use_symlinks (`"auto"` or `bool`, defaults to `"auto"`):
            To be used with `local_dir`. If set to "auto", the cache directory will be used and the file will be either
            duplicated or symlinked to the local directory depending on its size. It set to `True`, a symlink will be
            created, no matter the file size. If set to `False`, the file will either be duplicated from cache (if
            already exists) or downloaded from the Hub and not cached. See description for more details.
        user_agent (`dict`, `str`, *optional*):
            The user-agent info in the form of a dictionary or a string.
        force_download (`bool`, *optional*, defaults to `False`):
            Whether the file should be downloaded even if it already exists in
            the local cache.
        proxies (`dict`, *optional*):
            Dictionary mapping protocol to the URL of the proxy passed to
            `requests.request`.
        etag_timeout (`float`, *optional*, defaults to `10`):
            When fetching ETag, how many seconds to wait for the server to send
            data before giving up which is passed to `requests.request`.
        resume_download (`bool`, *optional*, defaults to `False`):
            If `True`, resume a previously interrupted download.
        token (`str`, `bool`, *optional*):
            A token to be used for the download.
                - If `True`, the token is read from the HuggingFace config
                  folder.
                - If a string, it's used as the authentication token.
        local_files_only (`bool`, *optional*, defaults to `False`):
            If `True`, avoid downloading the file and return the path to the
            local cached file if it exists.
        legacy_cache_layout (`bool`, *optional*, defaults to `False`):
            If `True`, uses the legacy file cache layout i.e. just call [`hf_hub_url`]
            then `cached_download`. This is deprecated as the new cache layout is
            more powerful.

    Returns:
        Local path (string) of file or if networking is off, last version of
        file cached on disk.

    <Tip>

    Raises the following errors:

        - [`EnvironmentError`](https://docs.python.org/3/library/exceptions.html#EnvironmentError)
          if `token=True` and the token cannot be found.
        - [`OSError`](https://docs.python.org/3/library/exceptions.html#OSError)
          if ETag cannot be determined.
        - [`ValueError`](https://docs.python.org/3/library/exceptions.html#ValueError)
          if some parameter value is invalid
        - [`~utils.RepositoryNotFoundError`]
          If the repository to download from cannot be found. This may be because it doesn't exist,
          or because it is set to `private` and you do not have access.
        - [`~utils.RevisionNotFoundError`]
          If the revision to download from cannot be found.
        - [`~utils.EntryNotFoundError`]
          If the file to download cannot be found.
        - [`~utils.LocalEntryNotFoundError`]
          If network is disabled or unavailable and file is not found in cache.

    </Tip>
    """
    if HF_HUB_ETAG_TIMEOUT != DEFAULT_ETAG_TIMEOUT:
        # Respect environment variable above user value
        etag_timeout = HF_HUB_ETAG_TIMEOUT

    if force_filename is not None:
        warnings.warn(
            "The `force_filename` parameter is deprecated as a new caching system, "
            "which keeps the filenames as they are on the Hub, is now in place.",
            FutureWarning,
        )
        legacy_cache_layout = True

    if legacy_cache_layout:
        url = hf_hub_url(
            repo_id,
            filename,
            subfolder=subfolder,
            repo_type=repo_type,
            revision=revision,
            endpoint=endpoint,
        )

        return cached_download(
            url,
            library_name=library_name,
            library_version=library_version,
            cache_dir=cache_dir,
            user_agent=user_agent,
            force_download=force_download,
            force_filename=force_filename,
            proxies=proxies,
            etag_timeout=etag_timeout,
            resume_download=resume_download,
            token=token,
            local_files_only=local_files_only,
            legacy_cache_layout=legacy_cache_layout,
        )

    if cache_dir is None:
        cache_dir = HF_HUB_CACHE
    if revision is None:
        revision = DEFAULT_REVISION
    if isinstance(cache_dir, Path):
        cache_dir = str(cache_dir)
    if isinstance(local_dir, Path):
        local_dir = str(local_dir)
    locks_dir = os.path.join(cache_dir, ".locks")

    if subfolder == "":
        subfolder = None
    if subfolder is not None:
        # This is used to create a URL, and not a local path, hence the forward slash.
        filename = f"{subfolder}/{filename}"

    if repo_type is None:
        repo_type = "model"
    if repo_type not in REPO_TYPES:
        raise ValueError(f"Invalid repo type: {repo_type}. Accepted repo types are: {str(REPO_TYPES)}")

    storage_folder = os.path.join(cache_dir, repo_folder_name(repo_id=repo_id, repo_type=repo_type))
    os.makedirs(storage_folder, exist_ok=True)

    # cross platform transcription of filename, to be used as a local file path.
    relative_filename = os.path.join(*filename.split("/"))
    if os.name == "nt":
        if relative_filename.startswith("..\\") or "\\..\\" in relative_filename:
            raise ValueError(
                f"Invalid filename: cannot handle filename '{relative_filename}' on Windows. Please ask the repository"
                " owner to rename this file."
            )

    # if user provides a commit_hash and they already have the file on disk,
    # shortcut everything.
    if REGEX_COMMIT_HASH.match(revision):
        pointer_path = _get_pointer_path(storage_folder, revision, relative_filename)
        if os.path.exists(pointer_path):
            if local_dir is not None:
                return _to_local_dir(pointer_path, local_dir, relative_filename, use_symlinks=local_dir_use_symlinks)
            return pointer_path

    url = hf_hub_url(repo_id, filename, repo_type=repo_type, revision=revision, endpoint=endpoint)

    headers = build_hf_headers(
        token=token,
        library_name=library_name,
        library_version=library_version,
        user_agent=user_agent,
    )

    url_to_download = url
    etag = None
    commit_hash = None
    expected_size = None
    head_call_error: Optional[Exception] = None
    if not local_files_only:
        try:
            try:
                metadata = get_hf_file_metadata(
                    url=url,
                    token=token,
                    proxies=proxies,
                    timeout=etag_timeout,
                )
            except EntryNotFoundError as http_error:
                # Cache the non-existence of the file and raise
                commit_hash = http_error.response.headers.get(HUGGINGFACE_HEADER_X_REPO_COMMIT)
                if commit_hash is not None and not legacy_cache_layout:
                    no_exist_file_path = Path(storage_folder) / ".no_exist" / commit_hash / relative_filename
                    no_exist_file_path.parent.mkdir(parents=True, exist_ok=True)
                    no_exist_file_path.touch()
                    _cache_commit_hash_for_specific_revision(storage_folder, revision, commit_hash)
                raise

            # Commit hash must exist
            commit_hash = metadata.commit_hash
            if commit_hash is None:
                raise FileMetadataError(
                    "Distant resource does not seem to be on huggingface.co. It is possible that a configuration issue"
                    " prevents you from downloading resources from https://huggingface.co. Please check your firewall"
                    " and proxy settings and make sure your SSL certificates are updated."
                )

            # Etag must exist
            etag = metadata.etag
            # We favor a custom header indicating the etag of the linked resource, and
            # we fallback to the regular etag header.
            # If we don't have any of those, raise an error.
            if etag is None:
                raise FileMetadataError(
                    "Distant resource does not have an ETag, we won't be able to reliably ensure reproducibility."
                )

            # Expected (uncompressed) size
            expected_size = metadata.size

            # In case of a redirect, save an extra redirect on the request.get call,
            # and ensure we download the exact atomic version even if it changed
            # between the HEAD and the GET (unlikely, but hey).
            # Useful for lfs blobs that are stored on a CDN.
            if metadata.location != url:
                url_to_download = metadata.location
                # Remove authorization header when downloading a LFS blob
                headers.pop("authorization", None)
        except (requests.exceptions.SSLError, requests.exceptions.ProxyError):
            # Actually raise for those subclasses of ConnectionError
            raise
        except (
            requests.exceptions.ConnectionError,
            requests.exceptions.Timeout,
            OfflineModeIsEnabled,
        ) as error:
            # Otherwise, our Internet connection is down.
            # etag is None
            head_call_error = error
            pass
        except (RevisionNotFoundError, EntryNotFoundError):
            # The repo was found but the revision or entry doesn't exist on the Hub (never existed or got deleted)
            raise
        except requests.HTTPError as error:
            # Multiple reasons for an http error:
            # - Repository is private and invalid/missing token sent
            # - Repository is gated and invalid/missing token sent
            # - Hub is down (error 500 or 504)
            # => let's switch to 'local_files_only=True' to check if the files are already cached.
            #    (if it's not the case, the error will be re-raised)
            head_call_error = error
            pass
        except FileMetadataError as error:
            # Multiple reasons for a FileMetadataError:
            # - Wrong network configuration (proxy, firewall, SSL certificates)
            # - Inconsistency on the Hub
            # => let's switch to 'local_files_only=True' to check if the files are already cached.
            #    (if it's not the case, the error will be re-raised)
            head_call_error = error
            pass

    # etag can be None for several reasons:
    # 1. we passed local_files_only.
    # 2. we don't have a connection
    # 3. Hub is down (HTTP 500 or 504)
    # 4. repo is not found -for example private or gated- and invalid/missing token sent
    # 5. Hub is blocked by a firewall or proxy is not set correctly.
    # => Try to get the last downloaded one from the specified revision.
    #
    # If the specified revision is a commit hash, look inside "snapshots".
    # If the specified revision is a branch or tag, look inside "refs".
    if etag is None:
        # In those cases, we cannot force download.
        if force_download:
            raise ValueError(
                "We have no connection or you passed local_files_only, so force_download is not an accepted option."
            )

        # Try to get "commit_hash" from "revision"
        commit_hash = None
        if REGEX_COMMIT_HASH.match(revision):
            commit_hash = revision
        else:
            ref_path = os.path.join(storage_folder, "refs", revision)
            if os.path.isfile(ref_path):
                with open(ref_path) as f:
                    commit_hash = f.read()

        # Return pointer file if exists
        if commit_hash is not None:
            pointer_path = _get_pointer_path(storage_folder, commit_hash, relative_filename)
            if os.path.exists(pointer_path):
                if local_dir is not None:
                    return _to_local_dir(
                        pointer_path, local_dir, relative_filename, use_symlinks=local_dir_use_symlinks
                    )
                return pointer_path

        # If we couldn't find an appropriate file on disk, raise an error.
        # If files cannot be found and local_files_only=True,
        # the models might've been found if local_files_only=False
        # Notify the user about that
        if local_files_only:
            raise LocalEntryNotFoundError(
                "Cannot find the requested files in the disk cache and outgoing traffic has been disabled. To enable"
                " hf.co look-ups and downloads online, set 'local_files_only' to False."
            )
        elif isinstance(head_call_error, RepositoryNotFoundError) or isinstance(head_call_error, GatedRepoError):
            # Repo not found => let's raise the actual error
            raise head_call_error
        else:
            # Otherwise: most likely a connection issue or Hub downtime => let's warn the user
            raise LocalEntryNotFoundError(
                "An error happened while trying to locate the file on the Hub and we cannot find the requested files"
                " in the local cache. Please check your connection and try again or make sure your Internet connection"
                " is on."
            ) from head_call_error

    # From now on, etag and commit_hash are not None.
    assert etag is not None, "etag must have been retrieved from server"
    assert commit_hash is not None, "commit_hash must have been retrieved from server"
    blob_path = os.path.join(storage_folder, "blobs", etag)
    pointer_path = _get_pointer_path(storage_folder, commit_hash, relative_filename)

    os.makedirs(os.path.dirname(blob_path), exist_ok=True)
    os.makedirs(os.path.dirname(pointer_path), exist_ok=True)
    # if passed revision is not identical to commit_hash
    # then revision has to be a branch name or tag name.
    # In that case store a ref.
    _cache_commit_hash_for_specific_revision(storage_folder, revision, commit_hash)

    if os.path.exists(pointer_path) and not force_download:
        if local_dir is not None:
            return _to_local_dir(pointer_path, local_dir, relative_filename, use_symlinks=local_dir_use_symlinks)
        return pointer_path

    if os.path.exists(blob_path) and not force_download:
        # we have the blob already, but not the pointer
        if local_dir is not None:  # to local dir
            return _to_local_dir(blob_path, local_dir, relative_filename, use_symlinks=local_dir_use_symlinks)
        else:  # or in snapshot cache
            _create_symlink(blob_path, pointer_path, new_blob=False)
            return pointer_path

    # Prevent parallel downloads of the same file with a lock.
    # etag could be duplicated across repos,
    lock_path = os.path.join(locks_dir, repo_folder_name(repo_id=repo_id, repo_type=repo_type), f"{etag}.lock")

    # Some Windows versions do not allow for paths longer than 255 characters.
    # In this case, we must specify it is an extended path by using the "\\?\" prefix.
    if os.name == "nt" and len(os.path.abspath(lock_path)) > 255:
        lock_path = "\\\\?\\" + os.path.abspath(lock_path)

    if os.name == "nt" and len(os.path.abspath(blob_path)) > 255:
        blob_path = "\\\\?\\" + os.path.abspath(blob_path)

    Path(lock_path).parent.mkdir(parents=True, exist_ok=True)
    with FileLock(lock_path):
        # If the download just completed while the lock was activated.
        if os.path.exists(pointer_path) and not force_download:
            # Even if returning early like here, the lock will be released.
            return pointer_path

        if resume_download:
            incomplete_path = blob_path + ".incomplete"

            @contextmanager
            def _resumable_file_manager() -> Generator[io.BufferedWriter, None, None]:
                with open(incomplete_path, "ab") as f:
                    yield f

            temp_file_manager = _resumable_file_manager
            if os.path.exists(incomplete_path):
                resume_size = os.stat(incomplete_path).st_size
            else:
                resume_size = 0
        else:
            temp_file_manager = partial(  # type: ignore
                tempfile.NamedTemporaryFile, mode="wb", dir=cache_dir, delete=False
            )
            resume_size = 0

        # Download to temporary file, then copy to cache dir once finished.
        # Otherwise you get corrupt cache entries if the download gets interrupted.
        with temp_file_manager() as temp_file:
            logger.info("downloading %s to %s", url, temp_file.name)

            if expected_size is not None:  # might be None if HTTP header not set correctly
                # Check tmp path
                _check_disk_space(expected_size, os.path.dirname(temp_file.name))

                # Check destination
                _check_disk_space(expected_size, os.path.dirname(blob_path))
                if local_dir is not None:
                    _check_disk_space(expected_size, local_dir)

            http_get(
                url_to_download,
                temp_file,
                proxies=proxies,
                resume_size=resume_size,
                headers=headers,
                expected_size=expected_size,
            )

        if local_dir is None:
            logger.debug(f"Storing {url} in cache at {blob_path}")
            _chmod_and_replace(temp_file.name, blob_path)
            _create_symlink(blob_path, pointer_path, new_blob=True)
        else:
            local_dir_filepath = os.path.join(local_dir, relative_filename)
            os.makedirs(os.path.dirname(local_dir_filepath), exist_ok=True)

            # If "auto" (default) copy-paste small files to ease manual editing but symlink big files to save disk
            # In both cases, blob file is cached.
            is_big_file = os.stat(temp_file.name).st_size > constants.HF_HUB_LOCAL_DIR_AUTO_SYMLINK_THRESHOLD
            if local_dir_use_symlinks is True or (local_dir_use_symlinks == "auto" and is_big_file):
                logger.debug(f"Storing {url} in cache at {blob_path}")
                _chmod_and_replace(temp_file.name, blob_path)
                logger.debug("Create symlink to local dir")
                _create_symlink(blob_path, local_dir_filepath, new_blob=False)
            elif local_dir_use_symlinks == "auto" and not is_big_file:
                logger.debug(f"Storing {url} in cache at {blob_path}")
                _chmod_and_replace(temp_file.name, blob_path)
                logger.debug("Duplicate in local dir (small file and use_symlink set to 'auto')")
                shutil.copyfile(blob_path, local_dir_filepath)
            else:
                logger.debug(f"Storing {url} in local_dir at {local_dir_filepath} (not cached).")
                _chmod_and_replace(temp_file.name, local_dir_filepath)
            pointer_path = local_dir_filepath  # for return value

    return pointer_path


@validate_hf_hub_args
def try_to_load_from_cache(
    repo_id: str,
    filename: str,
    cache_dir: Union[str, Path, None] = None,
    revision: Optional[str] = None,
    repo_type: Optional[str] = None,
) -> Union[str, _CACHED_NO_EXIST_T, None]:
    """
    Explores the cache to return the latest cached file for a given revision if found.

    This function will not raise any exception if the file in not cached.

    Args:
        cache_dir (`str` or `os.PathLike`):
            The folder where the cached files lie.
        repo_id (`str`):
            The ID of the repo on huggingface.co.
        filename (`str`):
            The filename to look for inside `repo_id`.
        revision (`str`, *optional*):
            The specific model version to use. Will default to `"main"` if it's not provided and no `commit_hash` is
            provided either.
        repo_type (`str`, *optional*):
            The type of the repository. Will default to `"model"`.

    Returns:
        `Optional[str]` or `_CACHED_NO_EXIST`:
            Will return `None` if the file was not cached. Otherwise:
            - The exact path to the cached file if it's found in the cache
            - A special value `_CACHED_NO_EXIST` if the file does not exist at the given commit hash and this fact was
              cached.

    Example:

    ```python
    from huggingface_hub import try_to_load_from_cache, _CACHED_NO_EXIST

    filepath = try_to_load_from_cache()
    if isinstance(filepath, str):
        # file exists and is cached
        ...
    elif filepath is _CACHED_NO_EXIST:
        # non-existence of file is cached
        ...
    else:
        # file is not cached
        ...
    ```
    """
    if revision is None:
        revision = "main"
    if repo_type is None:
        repo_type = "model"
    if repo_type not in REPO_TYPES:
        raise ValueError(f"Invalid repo type: {repo_type}. Accepted repo types are: {str(REPO_TYPES)}")
    if cache_dir is None:
        cache_dir = HF_HUB_CACHE

    object_id = repo_id.replace("/", "--")
    repo_cache = os.path.join(cache_dir, f"{repo_type}s--{object_id}")
    if not os.path.isdir(repo_cache):
        # No cache for this model
        return None

    refs_dir = os.path.join(repo_cache, "refs")
    snapshots_dir = os.path.join(repo_cache, "snapshots")
    no_exist_dir = os.path.join(repo_cache, ".no_exist")

    # Resolve refs (for instance to convert main to the associated commit sha)
    if os.path.isdir(refs_dir):
        revision_file = os.path.join(refs_dir, revision)
        if os.path.isfile(revision_file):
            with open(revision_file) as f:
                revision = f.read()

    # Check if file is cached as "no_exist"
    if os.path.isfile(os.path.join(no_exist_dir, revision, filename)):
        return _CACHED_NO_EXIST

    # Check if revision folder exists
    if not os.path.exists(snapshots_dir):
        return None
    cached_shas = os.listdir(snapshots_dir)
    if revision not in cached_shas:
        # No cache for this revision and we won't try to return a random revision
        return None

    # Check if file exists in cache
    cached_file = os.path.join(snapshots_dir, revision, filename)
    return cached_file if os.path.isfile(cached_file) else None


@validate_hf_hub_args
def get_hf_file_metadata(
    url: str,
    token: Union[bool, str, None] = None,
    proxies: Optional[Dict] = None,
    timeout: Optional[float] = DEFAULT_REQUEST_TIMEOUT,
) -> HfFileMetadata:
    """Fetch metadata of a file versioned on the Hub for a given url.

    Args:
        url (`str`):
            File url, for example returned by [`hf_hub_url`].
        token (`str` or `bool`, *optional*):
            A token to be used for the download.
                - If `True`, the token is read from the HuggingFace config
                  folder.
                - If `False` or `None`, no token is provided.
                - If a string, it's used as the authentication token.
        proxies (`dict`, *optional*):
            Dictionary mapping protocol to the URL of the proxy passed to
            `requests.request`.
        timeout (`float`, *optional*, defaults to 10):
            How many seconds to wait for the server to send metadata before giving up.

    Returns:
        A [`HfFileMetadata`] object containing metadata such as location, etag, size and
        commit_hash.
    """
    headers = build_hf_headers(token=token)
    headers["Accept-Encoding"] = "identity"  # prevent any compression => we want to know the real size of the file

    # Retrieve metadata
    r = _request_wrapper(
        method="HEAD",
        url=url,
        headers=headers,
        allow_redirects=False,
        follow_relative_redirects=True,
        proxies=proxies,
        timeout=timeout,
    )
    hf_raise_for_status(r)

    # Return
    return HfFileMetadata(
        commit_hash=r.headers.get(HUGGINGFACE_HEADER_X_REPO_COMMIT),
        # We favor a custom header indicating the etag of the linked resource, and
        # we fallback to the regular etag header.
        etag=_normalize_etag(r.headers.get(HUGGINGFACE_HEADER_X_LINKED_ETAG) or r.headers.get("ETag")),
        # Either from response headers (if redirected) or defaults to request url
        # Do not use directly `url`, as `_request_wrapper` might have followed relative
        # redirects.
        location=r.headers.get("Location") or r.request.url,  # type: ignore
        size=_int_or_none(r.headers.get(HUGGINGFACE_HEADER_X_LINKED_SIZE) or r.headers.get("Content-Length")),
    )


def _int_or_none(value: Optional[str]) -> Optional[int]:
    try:
        return int(value)  # type: ignore
    except (TypeError, ValueError):
        return None


def _chmod_and_replace(src: str, dst: str) -> None:
    """Set correct permission before moving a blob from tmp directory to cache dir.

    Do not take into account the `umask` from the process as there is no convenient way
    to get it that is thread-safe.

    See:
    - About umask: https://docs.python.org/3/library/os.html#os.umask
    - Thread-safety: https://stackoverflow.com/a/70343066
    - About solution: https://github.com/huggingface/huggingface_hub/pull/1220#issuecomment-1326211591
    - Fix issue: https://github.com/huggingface/huggingface_hub/issues/1141
    - Fix issue: https://github.com/huggingface/huggingface_hub/issues/1215
    """
    # Get umask by creating a temporary file in the cached repo folder.
    tmp_file = Path(dst).parent.parent / f"tmp_{uuid.uuid4()}"
    try:
        tmp_file.touch()
        cache_dir_mode = Path(tmp_file).stat().st_mode
        os.chmod(src, stat.S_IMODE(cache_dir_mode))
    finally:
        tmp_file.unlink()

    shutil.move(src, dst)


def _get_pointer_path(storage_folder: str, revision: str, relative_filename: str) -> str:
    # Using `os.path.abspath` instead of `Path.resolve()` to avoid resolving symlinks
    snapshot_path = os.path.join(storage_folder, "snapshots")
    pointer_path = os.path.join(snapshot_path, revision, relative_filename)
    if Path(os.path.abspath(snapshot_path)) not in Path(os.path.abspath(pointer_path)).parents:
        raise ValueError(
            "Invalid pointer path: cannot create pointer path in snapshot folder if"
            f" `storage_folder='{storage_folder}'`, `revision='{revision}'` and"
            f" `relative_filename='{relative_filename}'`."
        )
    return pointer_path


def _to_local_dir(
    path: str, local_dir: str, relative_filename: str, use_symlinks: Union[bool, Literal["auto"]]
) -> str:
    """Place a file in a local dir (different than cache_dir).

    Either symlink to blob file in cache or duplicate file depending on `use_symlinks` and file size.
    """
    # Using `os.path.abspath` instead of `Path.resolve()` to avoid resolving symlinks
    local_dir_filepath = os.path.join(local_dir, relative_filename)
    if Path(os.path.abspath(local_dir)) not in Path(os.path.abspath(local_dir_filepath)).parents:
        raise ValueError(
            f"Cannot copy file '{relative_filename}' to local dir '{local_dir}': file would not be in the local"
            " directory."
        )

    os.makedirs(os.path.dirname(local_dir_filepath), exist_ok=True)
    real_blob_path = os.path.realpath(path)

    # If "auto" (default) copy-paste small files to ease manual editing but symlink big files to save disk
    if use_symlinks == "auto":
        use_symlinks = os.stat(real_blob_path).st_size > constants.HF_HUB_LOCAL_DIR_AUTO_SYMLINK_THRESHOLD

    if use_symlinks:
        _create_symlink(real_blob_path, local_dir_filepath, new_blob=False)
    else:
        shutil.copyfile(real_blob_path, local_dir_filepath)
    return local_dir_filepath