103 lines
3.6 KiB
Python
103 lines
3.6 KiB
Python
import hashlib
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import os
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import shutil
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import sys
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import tempfile
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from urllib.request import urlopen, Request
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try:
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from tqdm.auto import tqdm # automatically select proper tqdm submodule if available
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except ImportError:
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try:
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from tqdm import tqdm
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except ImportError:
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# fake tqdm if it's not installed
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class tqdm(object): # type: ignore
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def __init__(self, total=None, disable=False,
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unit=None, unit_scale=None, unit_divisor=None):
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self.total = total
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self.disable = disable
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self.n = 0
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# ignore unit, unit_scale, unit_divisor; they're just for real tqdm
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def update(self, n):
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if self.disable:
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return
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self.n += n
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if self.total is None:
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sys.stderr.write("\r{0:.1f} bytes".format(self.n))
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else:
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sys.stderr.write("\r{0:.1f}%".format(100 * self.n / float(self.total)))
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sys.stderr.flush()
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def __enter__(self):
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return self
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def __exit__(self, exc_type, exc_val, exc_tb):
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if self.disable:
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return
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sys.stderr.write('\n')
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def download_url_to_file(url, dst, hash_prefix=None, progress=True):
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r"""Download object at the given URL to a local path.
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Args:
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url (string): URL of the object to download
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dst (string): Full path where object will be saved, e.g. `/tmp/temporary_file`
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hash_prefix (string, optional): If not None, the SHA256 downloaded file should start with `hash_prefix`.
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Default: None
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progress (bool, optional): whether or not to display a progress bar to stderr
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Default: True
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Example:
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>>> torch.hub.download_url_to_file('https://s3.amazonaws.com/pytorch/models/resnet18-5c106cde.pth', '/tmp/temporary_file')
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"""
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file_size = None
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# We use a different API for python2 since urllib(2) doesn't recognize the CA
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# certificates in older Python
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req = Request(url, headers={"User-Agent": "torch.hub"})
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u = urlopen(req)
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meta = u.info()
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if hasattr(meta, 'getheaders'):
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content_length = meta.getheaders("Content-Length")
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else:
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content_length = meta.get_all("Content-Length")
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if content_length is not None and len(content_length) > 0:
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file_size = int(content_length[0])
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# We deliberately save it in a temp file and move it after
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# download is complete. This prevents a local working checkpoint
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# being overridden by a broken download.
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dst = os.path.expanduser(dst)
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dst_dir = os.path.dirname(dst)
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f = tempfile.NamedTemporaryFile(delete=False, dir=dst_dir)
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try:
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if hash_prefix is not None:
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sha256 = hashlib.sha256()
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with tqdm(total=file_size, disable=not progress,
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unit='B', unit_scale=True, unit_divisor=1024) as pbar:
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while True:
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buffer = u.read(8192)
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if len(buffer) == 0:
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break
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f.write(buffer)
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if hash_prefix is not None:
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sha256.update(buffer)
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pbar.update(len(buffer))
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f.close()
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if hash_prefix is not None:
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digest = sha256.hexdigest()
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if digest[:len(hash_prefix)] != hash_prefix:
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raise RuntimeError('invalid hash value (expected "{}", got "{}")'
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.format(hash_prefix, digest))
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shutil.move(f.name, dst)
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finally:
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f.close()
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if os.path.exists(f.name):
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os.remove(f.name)
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